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Abstract
Inorganic aerogels with low density, high porosity, large specific surface area, and superior mechanical properties are excellent candidate materials in fields such as thermal management, energy, catalysis, and biomedical applications. A comprehensive overview of existing elastic inorganic aerogels is provided, covering their structural units, preparation methods, mechanical performances, and applications. Meanwhile, based on the constituent building blocks and microstructures, a detailed analysis of the mechanical properties and guidelines for elastic design of aerogels is presented. Concluding with a succinct summary of prospective developmental direction, this review deliberates on the challenges and potential opportunities of elastic inorganic aerogels, with the intent of providing a versatile platform for designing new types of elastic inorganic aerogels for various applications.
KEYWORDS inorganic aerogels, compressive, stretchable, fabrication, mechanical performances, applications 1 Introduction Aerogels, which were ranked as one of top ten emerging technologies in chemistry 2022 by the International Union of Pure and Applied Chemistry (IUPAC), have garnered significant attention due to their characteristics such as low density, high porosity, and large specific surface area [1−5]. Among these, inorganic aerogels, owing to properties like high electrical conductivity of carbon and metallic materials, high-temperature resistance and piezoelectric behavior of ceramic material have emerged as excellent candidate materials in fields such as thermal management, energy, catalysis, and biomedical applications [6−9]. Since 1931, the definition of aerogels has been used to describe a class of highly porous materials formed by the sol–gel process and supercritical drying [10]. The three-dimensional (3D) network of these aerogels is usually formed by the controlled condensation of small sol nanoparticles (colloids) with a diameter of 1–3 nm, and the porosity is usually above 90%. It should be noted that due to the weak inter-particulate interactions of the traditional aerogels, the inferior mechanical properties (such as high brittleness) make them difficult to self-support, and remain a restriction for their practical applications [11, 12]. For instance, the most commonly encountered and commercial SiO2 nanoparticle aerogel often requires composite reinforcement with fibrous materials to achieve self-supporting structures [13−17]. Nevertheless, this composite material still exhibits poor structural stability and susceptibility to powdering [18, 19]. Extensive research has indicated that nano particles with smaller size exhibit toxicity upon absorption into the human body [20, 21]. The particulate nanomaterials are challenging to recycle and collect, posing a severe threat to the health of organisms upon release into the environment [22]. In this context, mixtures containing 1% or more of powdered substances, in particulate form with aerodynamic diameters ≤ 10 μm, were officially categorized as gategory 2 carcinogens by the European Union in February 2020 [23]. In order to overcome the inherent brittleness of inorganic aerogels, an increasing number of researchers have dedicated their efforts to the research of the field of elastic inorganic aerogels [7, 24−27]. Of particular note are encouraging results in the field of elastic inorganic aerogels, where a large number of such aerogels have been developed. For instance, a range of ceramic aerogels [28−32], carbon aerogels [33−37], and metallic aerogels [38−44] prepared by new methodologies including freeze-drying, chemical vapor deposition (CVD), 3D printing, templating, and foaming, have demonstrated remarkable compressive elasticity. Moreover, to cater to more intricate application environments and demands, elastic inorganic aerogels with bending and stretchability have also been reported [45−47]. Broadly speaking, although the traditional sol–gel process is absent in some cases, these 3D porous materials are widely accepted as aerogels as well since they possess the unique features of aerogels such as high porosity and large surface area. This outstanding elastic deformation capacity confers the ability to effectively mitigate strength degradation and residual stresses following mechanical loads, avoiding fracture or collapse during application. Moreover, the outstanding stretchability potential may provide opportunities for inorganic aerogels to be used in domains such as wearable electronic devices. This review predominantly focuses on the preparation criteria and mechanical properties of inorganic aerogels with outstanding Address correspondence to Fan Wu, dhfzwufan@163.com; Bin Ding, binding@dhu.edu.cn elasticity, aiming to comprehensively outline the latest advancements in the preparation of elastic inorganic aerogels. As shown in Fig. 1, we begin by summarizing existing elastic inorganic aerogels based on their structural units, preparation methods, mechanical performances and applications, while briefly elucidating the preparation methods and inherent characteristics of various constituent units. The existing preparation methods and corresponding microstructural features of elastic inorganic aerogels are introduced. Subsequently, based on the constituent building blocks and microstructures, a detailed analysis of the mechanical properties and guidelines for elastic design of aerogels is presented. Concluding with a succinct summary of prospective application domains, this paper deliberates on the challenges and potential opportunities associated with elastic inorganic aerogels, accentuating their significant potential and development space, with the intent of guiding future research endeavors. 2 Constituent units The mechanical properties of aerogels are generally governed by the microstructure and inherent properties of the constituent units [7, 48]. For instance, the brittle “pearl necklace” connection structure between nanoparticle units in traditional inorganic nanoparticle aerogels often leads to brittle fracture and pulverization under external forces [13]. To date, the attainment of elastic inorganic aerogels has often been achieved by selecting or synthesizing continuous and flexible one-dimensional (1D) nanowires, nanofibers with certain aspect ratios, and twodimensional (2D) layered materials to construct fine structural engineering [49−51]. For instance, many inorganic aerogel materials such as elastic SiC nanowire aerogels [52−55], ceramic nanofiber aerogels [56−61], graphene nanosheet aerogels [62−71], and boron nitride (BN) nanosheet aerogels [72−75] have been prepared by methods such as synthesizing nanowires extending up to several tens of micrometers in length through CVD, preparing flexible ceramic nanofibers using electrospinning, selecting graphene nanosheets with exceptional mechanical properties, and designing regular honeycomb cellular structures or parallel-stacked multi-arch configurations. As demonstrated in Tables 1 and 2, we have compiled a selection of representative elastic aerogels, outlining their structural constituents, mechanical properties, and preparation methods. 3 Preparation and structure of elastic inorganic aerogels The mechanical properties of aerogels are highly contingent upon their constituent units and microstructure. By employing diverse preparation methods, 1D and 2D constituent units can be prepared into elastic inorganic aerogels with various microstructures. In this section, we present recently reported methods and attributes for preparing elastic inorganic aerogels, encompassing methods such as gel drying, template-sacrificing, foaming sol–gel, CVD, 3D printing, freeze-drying, and electrospinning. 3.1 Gel drying method Gel drying involves the transformation of a precursor solution into a solid network saturated with liquid, followed by the removal of solvents from the wet gel using less invasive drying methods such as supercritical drying, in order to obtain an aerogel [76−83]. Currently, this method is primarily employed in the preparation Nano Res. 2024, 17(10): 8842–8862 8843 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research of elastic 1D inorganic nanowire and nanofiber aerogels. For instance, Yu et al. utilized cationic surfactant cetyltrimethylammonium bromide (CTAB) as a stabilizer between negatively charged bacterial cellulose nanofibers (BCNFs) and resorcinol-formaldehyde to form a uniform solution [84]. Subsequently, an overall resorcinol-formaldehyde (RF) gel was obtained through solvent thermal polymerization and CO2 supercritical drying. Elastic carbon nanofiber aerogels with exceptional elasticity were then obtained by carburization at 800 °C under an inert gas atmosphere (Fig. 2(a)). After RF pyrolysis, the joints between the fibers were welded, resulting in a randomly distributed nanofiber network structure with numerous robust joints (Figs. 2(b)−2(e)). Kim et al. utilized van der Waals forces between carbon nanotubes (CNTs) to prepare wet gels and subsequently obtained elastic carbon nanotube aerogels [85]. Jun et al. directly obtained porous nanowire hydrogels through a hydrothermal synthesis method, followed by supercritical drying to obtain elastic K2−xMn8O16 nanowire aerogels with Table 1 Units of inorganic aerogels with compressive properties Units Cyclic compressivenumbers and strain Plastic deformation Synthetic strategy References 1D Compressive Carbon nanofiber 1000-cycles, 70% 8% Gelation [84] 100-cycles, 50% 0 Electrospinning + freeze-drying [164] 500-cycles, 50% 9.4% Freeze-drying [111] 10000-cycles, 80% 6.5% Freeze-drying [113] Carbon nanofiber + nanosheet 3000-cycles, 50% 0 Freeze-drying [139] GO + tubular carbon nanofiber 50-cycles, 50% 5% Freeze-drying [165] Carbon nanofibers + SiC 1000-cycles, 60% 4% Gelation + CVD [114] Carbon nanofiber + FeS2 nanowire 1-cycle, 50% 0 CVD + freeze-drying [131] CNT 1000-cycles, 95% 9% Gelation + freeze-drying [166] CNT + SiO2 nanofiber 500-cycles, 60% 19% Freeze-drying [112] SiC nanowire 100-cycles, 10% 3% Template + 3D printing + CVD [126] SiC nanowire 100-cycles, 40% — Template + gelation [167] SiC nanowire 1000-cycles, 60% 6.5% CVD [91] SiC + SiO2 nanowire 10-cycles, 60% 0 CVD + freeze-drying [54] SiC/SiOx core−shell nanofibers 1000-cycles, 50% 9.2% CVD [93] Si3N4 nanofiber + SiOx nanowire 500-cycles, 50% 0 CVD + freeze-drying [57] SiO2 nanofiber 1000-cycles, 50% 3.1% Electrospinning + freeze-drying [134] SiO2 nanofiber + SiO2 nanoparticle 1000-cycles, 50% 19.8% Electrospinning + freeze-drying [121] ZrO2-SiO2 nanofiber 1000-cycles, 60% 1.2% Electrospinning + freeze-drying [58] ZrO2-Al2O3 nanofiber 1000-cycles, 60% 12.5% Electrospinning + freeze-drying [110] ZrO2-SiO2 nanofiber 1000-cycles, 60% 0 Electrospinning + freeze-drying [60] TiO2 nanofiber 100-cycles, 25% 4.8% Electrospinning + freeze-drying [23] h-BN/SiO2 nanofiber 1-cycle, 60% — Electrospinning + freeze-drying [122] Cu nanowire 1-cycle, 60% — Freeze-drying [38] Cu nanowire 1-cycle, 90% — Freeze-drying [40] Au Nanowire 1-cycle, 20% 9% Freeze-drying [41] Ag Nanowire 100-cycles, 20% 10% 3D printing freeze-drying [42] Carbon-wrapped metallic nanowire 10-cycles, 90% 0 Gelation + freeze-drying [133] 2D compressive GO 100-cycles, 95% — Freeze + gelation [140] GO 5-cycles, 30% 0 3D printing + freeze-drying [127] GO 100-cycles, 50% 0 Freeze-drying [138] GO 50-cycles, 50% 7% Freeze-drying [116] GO 1-cycle, 50% 0 Foaming [90] GO 1000-cycles, 70% 0 Foaming [89] Giant graphene oxide + CNT 1000-cycles, 50% 0 Freeze-drying [68] Graphene 10-cycles, 90% — Template + CVD [87] Graphene/Al2O3 200-cycles, 80% — Freeze-drying + ALD [124] rGO/carbon nanowire 100-cycles, 90% 0 Freeze-drying [136] Graphene + CNT 2000-cycles, 60% 0 Gelation [130] Mxene 50-cycles, 10% 1% 3D printing + freeze-drying [129] MXene/rGO 100-cycles, 50% 0 Freeze-drying [119] BN 10-cycles, 80% 0 Template [75] BN, SiC 100-cycles, 90% 4% Freeze-drying [2] 8844 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp interconnected ultra-long nanowire network structures [86]. These nanowire hydrogels self-assembled during the hydrothermal reaction process as nanowire length and concentration increased gradually. By adjusting raw materials and process parameters, this method can be used to prepare anatase TiO2 nanowire aerogels. 3.2 Template-sacrificing method The template-sacrificing method involves combining the target product with a porous substrate through methods such as CVD or coating, followed by removing the substrate to obtain porous framework materials or aerogel materials. For instance, Yin et al. employed CVD and nickel foam templates to prepare hierarchical structure 3D hollow tubular BN foams with an ultra-low density of 1.6 mg·cm−3 [75]. Bi et al. utilized mesoporous SiO2 bulk material as a template and grew tubular graphene through CVD onto the template, subsequently removing the template with an HF solution [87]. After high-temperature treatment, they obtained an elastic graphene aerogel with a 3D continuous hollow tubular network, as shown in the Figs. 3(a)−3(e), with a large pore size of approximately 3 μm. Additionally, Zhao et al. coated reduced graphene oxide (rGO) onto a PU sponge, followed by carburization under argon protection [88]. They selectively burned off low-crystallinity carbon in air to obtain a highly elastic graphene aerogel. This aerogel exhibited a porous structure formed by interconnected graphene sheets, with pore sizes around 300 μm. Comparing the pore structures of graphene aerogels prepared from mesoporous SiO2 bulk material and PU sponge, it can be observed that the microstructure of aerogels prepared through the template-sacrificing method is determined by the microstructure of the template material and is based on the inherited structure of the template material. 3.3 Foaming method The foaming method involves the in-situ nucleation and growth of bubbles within a solution through physical, chemical, or the addition of inert gas methods. The foaming method is employed to continuously prepare elastic 2D inorganic sheet aerogels under open conditions. As depicted in the Fig. 4(a), when the aqueous slurry of GO is air-dried directly, the large surface tension at the gas–liquid interface causes the GO sheets to tend to stack layer by layer, forming a 2D dense film. However, most methods for preparing 2D inorganic sheet aerogels, such as freeze-drying, are conducted in enclosed spaces, making it difficult to achieve lowenergy input and continuous production. Qu et al. developed a method for preparing elastic inorganic aerogel based on foaming method. They employed surfactant foaming to obtain large-sized and structurally intact graphene hydrogel blocks [89]. The formation of the hydrogel is attributed to π–π interactions and hydrogen bonding effects between GO. After simple freeze-drying and air-drying, elastic GO aerogels with pore sizes of 100–300 micrometers and a wall thickness of about 40 nm can be prepared (Figs. 4(d) and 4(e)). Furthermore, through process control (such as increasing GO concentration, reducing foaming rate, coating thickness, and drying temperature), the Ostwald ripening process is delayed, reducing the freezing step, and further achieving the direct casting of 3D porous graphene aerogels under open conditions [90]. By combining techniques such as scraping or 3D printing (Fig. 4(c)), inorganic 2D sheet aerogels with different shapes and sizes can be directly prepared. 3.4 Chemical vapor deposition method CVD is a method that involves the generation of chemical and transport reactions of gaseous substrate on solid surface, leading to the deposition of solid sediments. Su et al. [91, 92] conducted a study in which, under an argon pressure of 0.25 MPa and at a Nano Res. 2024, 17(10): 8842–8862 8845 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research temperature of 1450 °C, the SiO and CO gases produced by the thermal decomposition of siloxane reacted with active graphite sites. This reaction resulted in the nucleation and continuous growth of SiC nanowires (Figs. 5(a)−5(c)). As the growth direction of nanowires is random, the resulting material structure is an aerogel film composed of interwoven nanowires assemblies. Through further stacking and self-bonding, a 3D bulk elastic SiCbased nanowire aerogel can be obtained. Ren et al. [93] reported a method combining CVD and layer-by-layer self-assembly. After the growth and formation of SiC nanofibers, an excess of SiO gas was randomly deposited in layers onto the nanofiber network and underwent transformation into SiOx shell structures at low temperatures. Subsequent cycles of CVD led to self-assembly and stacking (each cycle producing a layered nanofiber membrane with a thickness of 0.2–0.5 mm), resulting in the preparation of elastic inorganic nanofiber aerogels assembled from SiC/SiOx core–shell nanofibers. In addition to SiC-based aerogels, CVD can also be used to prepare elastic carbon aerogels. Gui et al. [94] employed ferrocene as a catalyst and carbon source to grow CNT aerogel-like bulk materials on quartz substrates, reaching a thickness of 0.8–1 cm. Wang et al. [47] collected self-assembled CNT cotton-like networks in a reaction zone using a rotating drum, obtaining a CNT aerogel-like bulk material with dimensions of 1.5 m in length, 1 m in width, and a thickness of 5–10 mm (Figs. 5(d)−5(i)). Furthermore, CVD can prepare multiwalled nanotube forests and pullout ultrathin carbon nanotube aerogel sheets from the sidewalls of the forest [95], exhibiting a bulk density of 1.5 mg·cm−3 and a thickness of 20 μm. Figure 3 Template-sacrificing method. (a) Schematic illustration of Template-sacrificing method. (b)–(e) Microstructure of elastic graphene aerogels with a 3D continuous hollow tubular network prepared by template-sacrificing method. Reproduced with permission from Ref. [87], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2015. Figure 4 Foaming method. (a)–(c) Schematic illustration of foaming method. (d)–(e) Microstructure of elastic graphene aerogels with pore sizes of 100–300 micrometers and a wall thickness of about 40 nm prepared by foaming method. Reproduced with permission from Ref. [90], © American Chemical Society 2020. 8846 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp 3.5 Freeze-drying method Freeze-drying method is the most widely used method for preparing ultra-light porous materials, enabling the preparation of elastic aerogels from 1D inorganic nanowires, nanofibers, and 2D nanosheets [96−101]. As depicted in the Fig. 6(a), the freezedrying process involves assembling elemental units into a network structure within an aqueous suspension at low temperatures, followed by sublimating the ice directly into the vapor phase under vacuum conditions. During the low temperature freezing, as ice crystals nucleate and grow [102], uniformly dispersed elemental units become enriched at crystal interfaces, and due to crystal expansion, they are compressed into thin lamellae, forming a hierarchical structure [103−106]. Furthermore, the structure of inorganic aerogels can be precisely controlled through process parameters such as freezing conditions (cooling rate, freezing time, and freezing direction), solvent composition, and slurry conditions (types of elements, content, additives, etc.) [107−109]. Numerous types of elastic inorganic aerogels have been prepared, including 1D materials such as nanofibers [110−115] and nanowires [40, 42, 54]; 2D materials like graphene [116−118], Mxene [119], and BN; 1D/2D composite materials such as CNT/graphene [68], SiO2 nanofibers/BN nanosheets [120], demonstrating the compatibility and versatility of the freezedrying method. The essential requirement for preparing elastic inorganic aerogels is that the nanoscale constituents units exhibit excellent flexibility. In our previous work, various flexible inorganic nanofiber membrane materials were prepared using electrospinning techniques, and 2D membrane materials were reconstructed into ultra-light and super-elastic inorganic nanofiber aerogels using freeze-drying [115]. The structure of these aerogels mainly consists of porous cell walls and layered cellular structures assembled from nanofibers (Figs. 6(b)−6(i)). Additionally, we achieved elastic ceramic nanofiber aerogels with layered arch-shaped cells through impregnation stacking assembly and freeze-drying [58]. Further optimization of the application performance, composite aerogels were achieved by introducing zero-dimensional nanoparticles [18, 121] and 2D nanosheets [120, 122, 123]. Moreover, Zhang et al. [124] utilized freeze-drying to prepare graphene aerogels, then constructed an Al2O3 layer on the graphene surface through atomic deposition to obtain ceramic/graphene materials. 3.6 3D printing method The 3D printing method is an additive manufacturing method that allows for the high precise and high rapid construction of materials with designed structures, offering an avenue for customized macroscopic geometry and microscopic structure of aerogels. Currently, there are two main methods for 3D printing to prepare elastic inorganic aerogels: direct ink writing and 3D freeze printing. In direct ink writing, the focus lies in adjusting the rheological properties of the ink to exhibit shear-thinning behavior, ensuring smooth extrusion and shape retention. To mitigate structural collapse due to liquid surface tension during subsequent drying, supercritical drying or freeze drying can be employed to remove the solvent [125]. 3D freeze printing involves extruding the solution onto a low-temperature frozen substrate to maintain the shape, followed by freeze-drying to remove the ice and obtain highly porous aerogels [126−128]. In order to develop printable GO inks, Zhu et al. utilized two methods, namely, ammonium hydroxide gelation and direct crosslinking using RF solution, to induce shear-thinning behavior in the GO suspension (Figs. 7(a) and 7(b)) [125]. Hydrophilic SiO2 powder was subsequently added to the GO suspension to further increase its viscosity. The wet gel formed by direct printing using a direct ink writing (DIW) apparatus was subjected to supercritical Figure 5 Chemical vapor deposition. (a)–(c) An aerogel film composed of interwoven nanowires assemblies prepared by CVD. Reproduced with permission from Ref. [92], © American Chemical Society 2021. (d)–(i) CNT aerogel-like bulk material with cotton-like networks prepared by CVD. Reproduced with permission from Ref. [47], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2017. Nano Res. 2024, 17(10): 8842–8862 8847 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research drying for solvent removal, followed by high-temperature nitrogen atmosphere treatment for thermal reduction (Fig. 7(c)). Finally, the elastic graphene aerogel with randomly distributed large pores is obtained by using etching to remove SiO2 nanoparticles in hydrofluoric acid (Figs. 7(d)−7(f)). Gao et al. employed CaCl2 as a crosslinker for GO, and directly 3D printed the GO ink into shape using DIW at room temperature [128]. Subsequently, the elastic rGO aerogel was obtained by freeze-drying to remove the solvent and then reducing it. This aerogel was printed into 2D porous graphene frameworks, forming a truss structure and woodpile structure. Guo et al. employed DIW to 3D print templates based on carbon fiber, followed by the subsequent growth of SiC on the carbon fibers through CVD, resulting in SiC nanowire aerogels with distinct hierarchical structures [126]. Additionally, Lin et al. reported 3D freeze printing, which does not require ink with viscoelastic shear-thinning behavior. Extruded droplets are directly frozen upon contact with a pre-cooled substrate, enabling layer-bylayer deposition to print complex 3D architectures [129]. After freeze-drying to remove the ice, an elastic Mxene aerogel with layered cellular structure was obtained. Similarly, Yan et al. utilized 3D freeze printing to prepare Ag nanowire aerogels with certain elasticity [42]. 3.7 Electrospinning method Electrospinning is a technique that employs electrostatic forces to stretch and refine electrojets into nanofibers. Upon formation from the Taylor cone due to the effect of electrostatic forces, the electrojet undergoes instability and results in the formation of a 3D crimped structure. While this crimped structure favors the formation of 3D bulk structures, the weak rigidity of the jet due to solvent surface tension and slow solidification causes the 3D crimped structure to gradually straighten or collapse into a dense structure on the receptive substrate. This limitation has hindered the direct preparation of inorganic nanofiber aerogels through electrospinning. Recently, we have developed a distinctive electrofluidic processing method known as “3D reactive electrospinning” [45], enabling the direct spinning of ceramic nanofiber aerogels with interwoven crimped fiber structures (Figs. 8(a)−8(c)). By modulating the protonation degree of the inorganic sol, we can microscopically control the gelation rate between colloidal particles, achieving the precise control of jet solidification within milliseconds. Gelation during the spinning process leads to rapid jet solidification, suppressing the deformation and collapse of the 3D crimped nanofiber structure. Subsequently, by adjusting the vertical movement of the receiving substrate and spinneret hole, we enhance the interlacing of crimped nanofibers, yielding precursor nanofiber aerogels with a 3D interwoven crimped fiber structure (Figs. 8(d)−8(g)). Finally, high-temperature calcination in air results in stretchable and compressible ceramic nanofiber aerogels. In comparison to traditional electrospinning for ceramic nanofiber fabrication, this method exhibits a 5 to 10-fold increase in production rate of single-spinneret and can achieve large-scale production. Utilizing this method, we achieved the preparation of Figure 6 Freeze-drying method. (a) Schematic illustration of freeze-drying method. (b)–(i) SiO2 nanofibrous aerogels with porous cell walls and layered cellular structures prepared by freeze-drying method. Reproduced with permission from Ref. [115], © Si, Y. et al. 2018. 8848 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp large size ceramic nanofiber aerogels measuring 170 cm in length, 130 cm in width, and 12 cm in height within 1 h. Among the current preparation methods, aerogels prepared by gel drying have smaller-scale structural units and smaller pore sizes. The structure of the materials prepared by the templatesacrificing method depends on the microstructure of the template material, and its molding is usually assisted by methods such as CVD or coating. Using bubbles and ice crystals as templates, the Figure 7 3D printing method. (a)–(c) 3D printing method based on direct ink writing. (d)–(f) GO aerogels prepared by 3D printing method. Reproduced with permission from Ref. [125], © Macmillan Publishers Limited 2015. Figure 8 Electrospinning. (a)–(c) Schematic illustration of 3D reactive electrospinning. (d)–(g) Microstructure of stretchable mullite nanofibrous aerogels with interwoven crimped nanofiber structures prepared by electrospinning. Reproduced with permission from Ref. [45], © Cheng, X. T. et al. 2022. Nano Res. 2024, 17(10): 8842–8862 8849 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research aerogels with customized structures could be obtained using the foaming method and the freeze-drying method. 3D printing method provides a new avenue to prepare aerogels with specific macroscopic geometry and microscopic structure with high precision. CVD and electrospinning method could prepare aerogels with high continuity building blocks and reversible bonding points, which is conducive to improving the multiple mechanical properties of aerogels. 4 Mechanical properties of elastic inorganic aerogels The elasticity of inorganic aerogels primarily depends on their constituent units and structure. Based on the aforementioned summaries, we find that the structure of aerogels is largely influenced by the preparation methods. Currently, the main constituent units capable of forming elastic inorganic aerogels are 1D nanowires, 1D nanofibers, 2D nanosheets, etc. Therefore, we will separately analyze the preparation and mechanical properties of 1D and 2D materials, transitioning from elasticity to flexibility and stretchability. 4.1 Elasticity of inorganic aerogels with 1D constituent units 4.1.1 Compressible inorganic aerogels As the most widely used method for preparing particle-based aerogel materials, the gel drying method has also been successfully applied to the preparation of 1D inorganic elastic aerogel materials. Examples include carbon nanotube, carbon nanofiber, and K2−xMn8O16 nanowire aerogels. For nanowires and nanofibers with lengths exceeding 10 μm, both direct synthesis and thermal treatment yield excellent elasticity in the resulting aerogels. For instance, K2−xMn8O16 with a density of 4 mg·cm−3 can recover to its initial shape after enduring 90% compressive strain, while the carbon nanofiber aerogel with a density of 9.2 mg·cm−3 shows only 8% plastic deformation after 1000 cycles of 70% compressive strain [86]. Yu et al. reported a kind of superelastic hard carbon aerogels composed merely of 1D nanofibers or nanowires [84]. Specifically, a variety of 1D nanofibers or nanowires were used as structural templates, which were joined by RF-derived hard carbon. Benefiting from the ultralong nanofiber network and the welded joints by the stiff hard carbon, the obtained aerogels exhibited superelasticity, as shown in Figs. 9(a) and 9(b), which contrasted with intrinsically brittle RF-based aerogels (with nanoparticle-stacked microstructure). Figure 9(c) illustrates the microstructure evolution during the compression. The structure became more compact, and the nanofibers bended slightly, which could almost completely recover after stress release. Kim et al. impregnated carbon nanotube hydrogels in a dilute solution of polyacrylonitrile, enabling penetration of low molecular weight polyacrylonitrile polymer into the hydrogel pores [130]. Subsequent supercritical drying and heat treatment resulted in graphene-wrapped carbon nanotube aerogels. These aerogels could recover their original shape after experiencing 90% compressive strain and exhibited no significant plastic deformation after 2000 cycles of 60% compressive strain. The preparation of 1D inorganic nano-unit elastic pure inorganic aerogels through 3D printing remains challenging. Guo et al. combined 3D printing and CVD methods to prepare SiC nanowire aerogels with certain elastic property [126]. This aerogel exhibited a layered microstructure with a scaffold diameter of approximately 460 micrometers and an average SiC nanowire diameter of around 132 nm. The aerogel displayed significant plastic deformation at 20% compressive strain, and after 100 compression cycles at 10% compressive strain, it still exhibited around 3% plastic deformation. Inorganic nanowire aerogels with excellent compressive elasticity can be prepared directly by CVD methods. For instance, SiC nanowire aerogels prepared by Su et al. had nanowire diameters of 20–50 nm, lengths ranging from tens to hundreds of micrometers, and bulk density of about 5 mg·cm−3 [91]. These aerogels demonstrated exceptional compressive elasticity, with only 6.5% plastic deformation after 1000 cycles of compression at 60% compressive strain. Simultaneously, their maximum stress, Young’s modulus, and energy loss coefficient remained almost constant. In-situ observations of the microstructure evolution during compression–recovery process revealed that the SiC nanowire aerogels underwent significant compression and densification upon loading stress (Figs. 10(a)−10(h)). The nanowires moved and deformed along the compression direction. Upon stress release, the nanowires returned to their initial positions and shapes without fracture or deformation. Thus, the excellent compressive resilience of inorganic aerogels directly prepared through CVD can be attributed to the high aspect ratio and flexibility of nanowires, 8850 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp allowing the nanowires with multiple deformation sites to transform the load into nanowire movement and bending deformation during compression, thereby avoiding structural fragmentation. Similarly, SiC aerogels prepared by Ren et al. experienced only 9.2% plastic deformation after 1000 cycles of 50% compression strain, with the maximum stress and Young’s modulus retention exceeding 90% (Figs. 10(i)−10(l)) [93]. Furthermore, CNT aerogels prepared by CVD methods with diameters of 20–30 nm exhibited no significant plastic deformation after undergoing 50% compressive strain. Subsequently, introducing FeS2 nanowires through freeze-drying and hydrothermal methods increased the compressive modulus and maximum stress with the increasing FeS2 contents. This composite aerogel displayed 8% plastic deformation at 70% large compressive strain [131]. In addition to 1D materials prepared by hydrothermal synthesis, CVD synthesis and natural 1D materials, inorganic nanofibers prepared through electrospinning are effective constituent units for preparing superelastic inorganic aerogels. In 2014, we firstly reported the construction of elastic ceramic/carbon inorganic aerogels by combining freeze-drying and electrospinning methods [132]. This aerogel exhibited only 14.5% plastic deformation after 1000 cycles of 60% strain. Subsequently, by optimizing the structure and composition, we reduced the plastic deformation to 4.3%. Moreover, we prepared ultra-light and superelastic ceramic nanofiber aerogels. As shown in the Figs. 11(a)−11(d), even after experiencing a large compression strain of 80%, this aerogel could still return to its initial state [115]. Following 500 cycles of 60% compression strain, it displayed only 12% plastic deformation, while maintaining an initial modulus and maximum stress of over 70%. Further insights gained from insitu scanning electron microscopy (SEM) and the Poisson’s ratio revealed that the superelastic of this aerogel primarily stemmed from the deformation behavior of pore inversion in a honeycomblike structure (Figs. 11(e)−11(g)). Even at 80% compression strain, the nanofiber cell walls largely avoided contact to enable lateral expansion, and the aerogel exhibited a slightly negative Poisson’s ratio (Fig. 11(h)). In comparison to the super-flexible SiO2, ceramic aerogels prepared with TiO2 nanofibers as constituent units exhibited a plastic deformation of 9.2% after 100 cycles of 40% strain, demonstrating the critical role of mechanical properties of constituent units in determining aerogel mechanical performance [23]. Moreover, considering the contribution of ceramic nanofiber length to structural mechanics, we directly stacked and freeze-dried nanofiber films to obtain ceramic nanofiber aerogels with a layered undulating cell structure. This aerogel achieved a maximum stress of 301 kPa at 80% strain and experienced only 1.2% plastic deformation after 1000 cycles of 60% strain [110]. Through in-situ compressive SEM observation, we discovered that the undulating cell structure deformed towards planarization after the aerogel underwent compressive force (Figs. 11(i) and 11(j)). Upon load release, the undulating cell structure recovered its original shape, maintaining the integrity of the aerogel’s structure and shape. Remarkably, this aerogel exhibited minimal plastic deformation after withstanding a weight load 8500 times than its own weight for 24 h, indicating exceptional structural durability. 4.1.2 Flexible, bendable and stretchable inorganic aerogels Currently, the preparation of inorganic aerogel materials with compressive elasticity through 1D materials has been extensively reported. However, the report of flexible, bendable, and stretchable inorganic aerogels remains limited. Wan et al. combined hydrothermal synthesis and freeze-drying to prepare Ag@C core–shell structured aerogel sponges with a 3D interconnected network structure, demonstrating excellent compressive elasticity and flexibility [133]. Undergoing 10 cycles of compression at 90% strain, no plastic deformation was observed. Additionally, the structure remained undamaged during bending and torsional deformation, as illustrated. Similarly, by adjusting the aspect ratio of length to diameter (L/d) of ceramic nanofibers, we prepared ceramic nanofiber aerogels that can fully recover after experiencing 85% bending strain (Fig. 12(a)) [134]. The Fig. 12(b) depicts that when the fiber diameter is short, significant cracking occurs after the ceramic nanofiber aerogel undergoes bending strain, while at an L/d ratio of 400, the aerogel structure remains Nano Res. 2024, 17(10): 8842–8862 8851 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research intact. Figure 12(c) shows that no cracks appear when the buckling strain increases to 85%. After bended to 1000 cycles, the maximum buckling stress of the aerogel remained ≥ 80% of the initial value (Fig. 12(d)). Preparing stretchable aerogels through freeze-drying still presents challenges, while using the CVD method can yield aerogel materials with certain tensile elasticity. Wang et al. employed the CVD method to prepare marshmallow-like pristine CNT foam, and further utilized CVD within the original CNT foam to establish junctions [47]. This aerogel-liked sponge can undergo stretching, compression, and twisting without fracturing. After multiple cycles of 25% tensile strain to 95% compressive strain, the material exhibited no significant plastic deformation. Amorphous carbon deposited at the nanotube junctions in the material anchored the nodes, preventing structural collapse from carbon nanotube detachment. However, with increasing deposition, the foam’s stiffness gradually increased, ultimately leading to loss of flexibility. This is attributed to excessive amorphous carbon hindering local bending and rotation of carbon nanotubes, causing stress concentration and structural damage. Similarly, Su et al. prepared SiC aerogels with a highly crimped nanowire network structure through CVD, capable of enduring 20% tensile strain without rupture [92]. After 100 cycles of stretching at 10% tensile strain, the aerogel exhibited only a 1% plastic deformation. Recently, we reported the preparation of ceramic nanofiber aerogels via reactive electrospinning, showcasing outstanding properties such as compressive elasticity, flexibility, and stretchability [45]. This aerogel showed no significant structural damage after undergoing 1000 cycles of compression strain (at 60% strain) and 1000 cycles of bulking strain (at 90% strain), and it could even be knotted like silk (Fig. 12(e)). Simultaneously, it could be stretched to 100% strain from its initial state without fracturing (Fig. 12(f)). As the tensile strain increased from 0% to 90%, the crimped ceramic nanofibers exhibited deflections, deformations, tight interlacing, and orientation caused by straightening (Fig. 12(g)). In contrast, the ceramic membrane with lamellar structure and straight nanofibers had smaller final strain (5%) and large module (Fig. 12(h)). The crimped ceramic nanofibers could be stretched from their original distance to 120% tensile strain without fracture (Fig. 12(i)), rendering the ceramic nanofibers robust for preventing breakage while the aerogels were stretched. At the nodes of the intertwined structure, stress was dispersed from one nanofiber to many others, preventing structural collapse (Fig. 12(j)). Additionally, after 1000 cycles of 40% tensile strain, no significant plastic deformation occurred in the aerogel, indicating structural stability (Fig. 12(k)). What’s more intriguing is that even after undergoing treatment at 1300 °C for 1 h, the aerogel could still endure 1000 cycles of stretching and recovery at 20% strain. 4.2 Elasticity of inorganic aerogels with 2D constituent units 4.2.1 Compressible inorganic aerogels Within 2D sheets, materials like graphene sheets, BN layers, and MXenes have been reported to enable the preparation of pure inorganic aerogels. For instance, Zhao et al. [88] demonstrated that graphene aerogels (ON/HG) prepared using a templatesacrificing method can return to their original state after experiencing significant compressive deformation. In contrast, graphene-coated PU-derived carbon aerogels (ON/G900) without calcination treatment collapsed completely after compression. This could be attributed to the stress concentration and brittle fracture resulting from the aggregation of particles in ON/G900. Similarly, Bi et al. achieved excellent compressive resilience with tubular graphene aerogels prepared using a template-sacrificing method, showing plastic deformation below 1% after undergoing 80% compression strain for 500 cycles [87]. Furthermore, Qu et al. [89, 90] demonstrated favorable compressive performance with graphene aerogels prepared through a foaming method. Even after Figure 11 Compressive properties of ceramic nanofibrous aerogels. (a)–(d) Compressive properties of SiO2 nanofibrous aerogels. (e) Sketch of the inversion of the nanofibrous cell walls under compression. SEM images showing the curvature radius of (f) a single cellular cell and (g) a single nanofiber. (h) Schematic illustration of the microstructure of a bent silica nanofiber Reproduced with permission from Ref. [115], © Si, Y. et al. 2018. (i) and (j) In-situ SEM images and schematic illustration of compressive process of ceramic nanofiber aerogels with a layered undulating cell structure. Reproduced with permission from Ref. [58], © American Chemical Society 2022. 8852 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp undergoing 1000 consecutive compression cycles at 70% strain, the aerogels maintained 99.3% of their original height and 96% of their maximum stress. 3D printing can prepare elastic aerogels with unique structures. Zhu et al. prepared a graphene aerogel framework using gelation method and 3D printing [125]. After 10 cycles of compression at 50% strain, no fractures occurred, and the maximum stress was maintained at 40%. Tang et al. used 3D freeze printing to prepare graphene aerogels that could recover to their initial state even after compression of 70%, demonstrating excellent compressibility [127]. During subsequent cyclic compression tests at 30% strain, no significant plastic deformation was observed after 5 compression cycles. Additionally, MXene aerogels prepared by Lin et al. maintained 88.8% of their maximum stress after 50 cycles of compression at 10% strain [129]. Freeze-drying is the most widely used method for preparing elastic inorganic aerogels. Among them, graphene aerogels with elasticity have gained significant attention. Currently, the optimization of freeze-dried graphene aerogels primarily focuses on enhancing the interactions between graphene layers and regulating their structure. The graphene aerogel annealed at 1000 °C could fully recover to their initial state after undergoing multiple cycles of compression at 98% strain [135]. In contrast, those annealed at 200 °C could not recover from large strain compression. High-temperature annealing can eliminate some of the oxygen-containing functional groups on GO sheets, leading to enhanced π–π stacking interactions between rGO layers. Jiang et al. [119] optimized the compressive elasticity of inorganic aerogels by annealing and adjusting the Mxene content in the rGO/Mxene. When the Mxene content exceeded 67%, the elastic recovery of the aerogel decreased due to excessive Mxene content hindering limited π–π stacking interactions. The inorganic aerogel with 50% Mxene content, annealed after 100 cycles of compression at 50% strain, exhibited no significant plastic deformation. Zhuo et al. [136] introduced a strong interaction (carbon welding) by constructing a layer of CNC, glucose, and urea carbonization between rGO layers, resulting in the formation of a flexible layer with reversible movement. Microstructural control of inorganic aerogels is an effective approach to optimize the mechanical properties of aerogel materials. As shown in Figs. 13(a)−13(d), Gao et al. prepared Cgraphene aerogels with multi-layered arched microstructures using freeze-drying [137]. After 10 cycles of compression at 80% strain, the aerogel could fully recover its initial height, exhibiting minimal variations in maximum stress and energy dissipation. In contrast, aerogels with disordered porous structures collapsed completely upon compression, with substantial energy dissipation. Aerogels possessing honeycomb-like cell structures showed elasticity during compression but exhibited certain plastic deformation, energy dissipation, and stress reduction. This is mainly due to irregular and multi-layered arched structures undergoing folding, bulking, or structural collapse under large compressive strains. C-graphene aerogels with multi-layered arched structures underwent rigorous cyclic compression (10,000 cycles at 80% strain) with only 7% plastic deformation, while maintaining a maximum stress of over 60%. The reason of the better compressive property was that the arch-shaped cylindrical thin-shell model can sustain large geometric deformation without yielding because of its small material strain, and it can also spring back to its original shape immediately, proved by mechanical simulations (Figs. 13(e)−13(g)). Similarly, Yang et al. [138], Min et al. [116], and Long et al. [139] obtained elastic graphene aerogels by controlling regular pore structures. Additionally, Xu et al. [140] achieved the preparation of elastic graphene aerogels under ambient conditions through a gelationassisted freezing method. The aerogel reached an ultra-high compressive strain of 99% under 1 MPa pressure and recovered to its initial shape. By adjusting the freezing temperature, they controlled over the Poisson’s ratio of aerogels, obtaining an inorganic aerogel with a negative Poisson’s ratio. Figure 12 Flexible, bendable, and stretchable properties of inorganic aerogels. (a)–(d) Bending properties of SiO2 nanofibrous aerogels with different aspect ratios of length to diameter. Reproduced with permission from Ref. [134], © Wiley-VCH GmbH 2020. (e)–(k) Flexible, bendable and stretchable properties of mullite nanofibrous aerogels with 3D interwoven crimped-nanofiber networks. Reproduced with permission from Ref. [45], © Cheng, X. T. et al. 2022. Nano Res. 2024, 17(10): 8842–8862 8853 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research Graphene/ceramic aerogels prepared by Zhang et al. [124] maintained elasticity and structural stability after 200 compressions at 80% strain. Moreover, overly thin ceramic wall layers exhibited limited elasticity, while excessively thick wall layers showed brittleness (Fig. 13(h)). Xu et al. [2] adjusted the wall thickness to prepare a double-layered superstructure in ceramic laminar aerogels, allowing them to recover their initial state after releasing stress at 95% compressive strain, as shown in the Figs. 13(i)−13(k). Simultaneously, the hyperbolic pattern structure caused the aerogel to undergo directed out-of-plane buckling of the unit walls during compression strain, exhibiting a negative Poisson’s ratio. 4.2.2 Bendable and stretchable inorganic aerogels It is highly challenging to prepare 2D nanosheet materials into bendable or stretchable aerogels. Similar to 1D nanomaterials, high aspect ratio 2D nanosheets can be prepared into flexible and bendable aerogels. Li et al. [141] prepared flexible and highly elastic BN nanobelt aerogels with an intertwined and entangled network structure from BN nanobelts obtained through hightemperature ammonolysis of trimeric cyanuric acid and boric acid, followed by freeze-drying. The BN nanobelts in this aerogel have widths ranging from 0.8 to 1.6 μm, thicknesses around 3.2 nm, and lengths of several hundred micrometers, displaying extremely high aspect ratios. Under 40% compressive strain, this aerogel exhibited a plastic deformation of 7.6% after 50 cycles and showed no fractures or damage following bending and twisting. Gao et al. [68] introduced CNTs with lengths reaching tens of micrometers into freeze-dried graphene aerogels, yielding a carbon aerogel with interconnected folded sheets. This aerogel displayed exceptional elasticity and a certain degree of stretchability, recovering to its initial state after 1000 cycles of 50% compressive strain and achieving an elongation at break of up to 16.5%. Moreover, Gao et al. [46] combined 3D printing and freezedrying to prepare a graphene/multi-walled carbon nanotube (MWNT) binary carbon aerogel with four hierarchical structural levels ranging from centimeters to molecular scales. The aerogel framework could be stretched to 100% strain and recover its initial state (Fig. 14(a)). Following 100 cycles of 100% strain stretching, the plastic deformation of the binary carbon aerogel was less than 1%, while the pure graphene aerogel exhibited a much higher plastic deformation of 65%. With an increase in the content of MWNTs, the energy loss of the binary carbon aerogel decreased from 0.3–0.6 to 0.15 for the pure graphene sample (Figs. 14(b) and 14(c)). This indicated minimal structural failure during cyclic stretching of the binary carbon aerogel. Furthermore, the aerogel maintained good fatigue resistance even under 200% cyclic stretching (Fig. 14(d)). During stretching, the 3D polygons expanded along the stretching direction, and the cell walls experienced reversible deformations including bending, twisting, stretching, and displacement. In-situ transmission electron microscopy (TEM) revealed that the thin walls intertwined with MWNTs and graphene did not separate after twisting, suggesting effective load transfer due to the strong connection achieved between graphene and MWNTs after chemical reduction (Figs. 14(e)−14(h)). These findings imply that the high stretchability of this binary aerogel stems from the combination effects of the multilayer hierarchical structure and the synergistic enhancement between MWNTs and graphene. Currently, the compression elasticity of inorganic aerogels can be easily achieved by enhancing the mechanical properties of building blocks and bonding points. Flexible structural units and rigid bonding points are most favorable for improving the resilience of the aerogels. However, the bending and stretching of inorganic aerogels are still difficult to achieve. Combined with the research reported so far, we believe that there are two key factors to improve the stretchability and bendability of inorganic aerogels: 1) Increase the aspect ratio of structural units and reduce the number of irreversible bonding points. The units with good continuity could improve the flexibility and stretching properties by sliding and entanglement; 2) for structural units that are short and the bonding points cannot be reduced, such as 2D graphene sheets, the flexibility and stretching properties of the material can be improved by macro-structural design, such as grid structure, Figure 13 Compressive properties of inorganic aerogels with 2D constituent units. (a)–(d) Compressive tests of graphene aerogels with different microstructures. (e) SEM images of multi-layered arched structures. (f) and (g) Strain (von Mises total strain) profiles of cylindrical shell under large geometry deformation using the finite element method. Reproduced with permission from Ref. [137], © Gao, H. L. et al. 2016. (h) Molecular dynamics (MD) simulations of deformability of hBNAGs with different wall thicknesses. (i)–(k) compressive properties of hBNAGs with different wall thicknesses. Reproduced with permission from Ref. [2], © Xu, X. et al. 2019. 8854 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp which could transform large strain into local small strain to realize the final stretchable and compressible properties. 5 Application researches of elastic aerogels 5.1 Sensing and electronic applications Due to their unique porous structures, elastic inorganic aerogels find extensive applications in electrode materials and sensor domains [142−147]. For instance, Lin et al. employed 3D MXene aerogels as electrodes to assemble micro-supercapacitors, demonstrating that enhancing the specific surface area of active material and altering the orientation of Mxene flakes effectively improve the electrochemical performance of electrode materials [148]. Gao et al. prepared GO aerogels with wrinkled porous structures for supercapacitor electrodes, as illustrated in the Fig. 15(a) [128]. Quasi-rectangular cyclic voltammetry (CV) curves confirmed their double-layer capacitance behavior. Moreover, the gradient porous structure of freeze-dried aerogels has been proven to facilitate rapid electrolyte ion diffusion. This GO aerogel exhibited higher capacitance retention and charge–discharge current density than most graphene-based supercapacitors (Fig. 15(b)). Han et al. utilized FeS2 nanowires and carbon nanotubes network aerogels as independent strain sensors and anodes for high-performance lithium-ion batteries [131]. As depicted in the Figs. 15(c) and 15(d), when connected to the fingertip of a robot, the double network nanowire aerogel accurately captured gestures such as gripping with four fingers, three fingers, and two fingers, demonstrating excellent sensitivity. Sun et al. prepared compressible and bendable carbon aerogels (Fig. 15(e)) for highly sensitive bend sensors under small strains [136]. As shown in the Fig. 15(f), the increase in bending angle led to significant resistance changes in the aerogel. When used to capture arterial signals, the sharp and regular signals obtained highlighted its immense potential in wearable sensors (Fig. 15(h)). Gao et al. produced carbon aerogels capable of full-range strain sensing (as shown in the Fig. 15(g), ranging from 20% compression to 100% extension) [46]. These aerogels exhibited distinct resistance changes under stress, with the resistance change pattern remaining nearly unchanged after 100 cycles (Figs. 15(i) and 15(j)). When attached to the joints of a snake-like robot, they accurately detected strain variations, including linear, crescent, S-shaped, and reverse Sshaped changes (Fig. 15(k)). 5.2 Thermal insulation applications Heat transfer in thermal insulation materials primarily involves heat convection, heat radiation, and solid conduction [149−151]. The porous structure and ultra-low density of elastic aerogels effectively reduce gas convection and solid conduction, making them ideal materials for high-temperature thermal insulation [152−154]. SiC nanowire aerogels prepared by Pan et al. exhibit anisotropic heat conductivity due to aligned gas transport channels in the axial direction, tortuous solid conduction paths in the radial direction, and stacking interfaces between nanowires (Fig. 16(a)) [54]. The radial and axial heat conductivities of the aerogel are 14 and 35 mW·m−1·K−1, respectively. Duan et al. prepared double-negative-index ceramic aerogels hBNAGs with 10 nm interfacial gaps in double panes, which effectively increase solid conduction paths and reduce heat conduction and convection (Fig. 16(b)) [2]. Similarly, our ceramic nanofibrous aerogels also demonstrate excellent high-temperature insulation performance. As shown in the Fig. 16(c), compared to iron, glass, and Al2O3 ceramic plates of the same thickness, our SiO2 nanofibrous aerogel provides better protection for petals on a 350 °C hotplate (Fig. 16(d)) [115]. After 30 min of heating on a 350 °C hotplate, the surface temperature of the 15 mm thick aerogel is only 63 °C. Furthermore, our mullite nanofibrous aerogels exhibit a backside temperature of only 121 °C when subjected to a butane flame at 1300 °C for 10 min (Fig. 16(e)) [45]. To further enhance the thermal insulation performance of elastic aerogels, we employ particle aerogels to construct closed-layer plug pores within them, further optimizing their high-temperature insulation capabilities [58]. This aerogel (1 cm thick), subjected to a butane flame for 5 min, exhibits an excellent high-temperature insulation Figure 14 Stretchable properties of inorganic aerogels with 2D constituent units. (a)–(c) Stretchable properties of carbon aerogel with increasing dose of MWNTs. (d) Cyclical tensile–release curves for a designed carbon aerogel with stretchable ratio of 200%. (e)–(h) The stretchable carbon aerogel exhibits recoverable tensile deformation in four orders of hierarchy. Reproduced with permission from Ref. [46], © Guo, F. et al. 2018. Nano Res. 2024, 17(10): 8842–8862 8855 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research performance with a backside temperature of only 67 °C. 5.3 Other applications In addition to its utilization in the fields of electrodes, sensors, and thermal insulation, elastic aerogels show promising prospects in applications such as seawater desalination, microwave absorption, oil absorption, and electrocatalytic nitrogen fixation [155−158]. The CNTs@SiO2 aerogel prepared by us exhibits high absorption with a value of 98% [112]. Under 1-sun illumination, it can elevate the temperature of water by 5.5 °C higher than that of pure water, as shown in the Fig. 17(a). When applied to the solar evaporator (Fig. 17(b)) we constructed, this aerogel achieves an evaporation rate of 1.5 kg·m−2·h−1. To further enhance the salt resistance of aerogels for desalination, we have developed an elastic inorganic aerogel inspired by reed leaves, demonstrating strong resistance to salinity [159]. Furthermore, we have created SiO2 nanofiber and BN nanoplate composite elastic aerogels for noise absorption, which exhibit excellent low-frequency microwave absorption performance (with a noise power coefficient of 0.59) [122]. As illustrated in the Fig. 17(c), compared to commercially available acoustic glass fiber felts, the layered structure of our composite aerogel results in lower volume density and superior sound absorption performance. Wang et al. prepared SiC aerogels with a density of 76 mg·cm3, achieving a minimum reflection loss of −43 dB and an effective absorption bandwidth of 2 GHz for a thickness of 4 mm [53]. Similarly, Liao et al. prepared Carbonwrapped metallic nanowire aerogels which, at an extremely low density of 3.82 mg·cm3, exhibit an EMI shielding efficiency of 70.1 dB in the frequency range of 8.2–18 GHz (Fig. 17(d)) [133]. Due to the unique oil-repellent and hydrophobic properties of graphene aerogels prepared by Liu et al. [118, 160], graphene aerogel microspheres and carbon aerogels prepared by Gao et al. [68, 161] have demonstrated excellent oil absorption characteristics. As depicted in the Fig. 17(e), for both toluene with lower density than water and dichloromethane with higher density than water, carbon aerogels achieve rapid adsorption. Additionally, we have explored the application of inorganic aerogels in the field of electrocatalytic nitrogen fixation [23]. By utilizing Li reduction on TiO2 aerogels to construct abundant oxygen vacancies, the aerogel achieves a NH3 production rate of 4.19 × 10−10 mol·s−1·cm−2 at the optimal potential (−0.55 V vs. RHE). As shown in the Figs. 17(f)−17(h), during cyclic electrocatalytic nitrogen fixation testing and a prolonged 24 h catalytic process, the NH3 production rate remains remarkably stable, demonstrating excellent reproducibility and long-term durability of its catalytic performance. Through simulated calculations on (101) crystal facets of TiO2 with and without oxygen vacancies, the surface with oxygen vacancies exhibits lower free energy during N2 reduction and a significantly reduced potential barrier during the thermodynamic process of nitrogen reduction, further confirming the outstanding electrocatalytic nitrogen fixation performance of this aerogel. 6 Prospects Compared with traditional brittle and hard inorganic aerogels, elastic aerogels prepared through various methods not only Figure 15 (a) CV curves for GO aerogels at scan rates from 10 to 500 mV·s−1. (b) The comparison of different graphene-based materials for supercapacitor electrodes Reproduced with permission from Ref. [128], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2018. (c) Robot hand with four fingertips attached with FeS2 nanowires and carbon nanotubes network aerogels. (d) Real-time current response of FeS2 nanowires and carbon nanotubes network aerogels attached on the robot hand to three hand gestures: four-fingers, two-fingers, and one-finger clenched. Reproduced with permission from Ref. [131], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2019. (e) Digital images of carbon aerogels before and after bending. (f) Bending-induced resistance as a function of tiny angle. (g) Flexible pressure sensor for biomonitoring with clear pulse signal at an interval of about 1.08s. Reproduced with permission from Ref. [136], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2018. (h) Stress–strain curves of stretchable carbon aerogels in a full strain range from +100% to −14%. (i) and (j) The evolution of resistance in the first 5 cycles and 100 cycles of stretchable carbon aerogels. (k) A three-localized carbon aerogels strain sensor array works as the logic sensor to identify the movement and configuration of a snake-like robot. Reproduced with permission from Ref. [46], © Guo, F. et al. 2018. 8856 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp possess reversible compressibility but can also exhibit flexural and stretchable properties. By combining the characteristics of constituent units such as carbon, ceramics, or metals with the features of low density, high porosity, and large specific surface area inherent to aerogel structures, elastic inorganic aerogels have found applications in diverse fields including batteries, sensors, Figure 16 (a) Schematic illustration showing the mechanism to achieve thermal superinsulation of SiC aerogels with a nanowire-assembled anisotropic and hierarchical microstructure. Reproduced with permission from Ref. [54], © Su, L. et al. 2020. (b) The extra tortuous solid conduction path in double-paned hBNAGs. Reproduced with permission from Ref. [2], © Xu, X. et al. 2019. (c)–(e) Thermal insulation of SiO2 nanofibrous aerogels and mullite aerogels. Reproduced with permission from Ref. [115], © Si, Y. et al. 2018. Reproduced with permission from Ref. [45], © Cheng, X. T. et al. 2022. Figure 17 (a) IR photographs of the aerogel and pure water under 1-sun illumination from 0 to 30 min. (b) Photograph of a solar evaporator with a considering cover. Reproduced with permission from Ref. [112], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2020. (c) Comparisons between SiO2/BN composite aerogels and commercial glass fiber mats. Reproduced with permission from Ref. [122], © American Chemical Society 2022. (d) SE absorption performance comparison of sponge in the frequency range of 8.2–12.4 GHz. Reproduced with permission from Ref. [133], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2018. (e) Snapshots of the adsorption process for toluene floating on water and chloroform on the bottom of the container. Reproduced with permission from Ref. [118], © WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2017. (f) Ammonia yields and Faradaic efficiencies of c-TiO2 aerogels. (g) Chronoamperometry curve of c-TiO2 aerogels. (h) Possible reaction mechanisms of nitrogen adsorption and reduction on the (101) plane of anatase TiO2 with and without OVs. Reproduced with permission from Ref. [23], © Wiley-VCH GmbH 2020. Nano Res. 2024, 17(10): 8842–8862 8857 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research thermal insulation, microwave absorption, oil absorption, seawater desalination, filtration, and air purification. Elastic inorganic aerogels have emerged as a novel developmental direction for optimizing aerogel material properties and expanding the scope of aerogel applications. In our view, the development of elastic inorganic aerogels should primarily focus on the following three directions: (1) Presently, carbon materials stand out as the most mechanically superior constituent units in elastic inorganic aerogels. However, other highly functional constituent units such as Mxene, ceramics, perovskites, and metals require further enhancement of their structural strength and flexibility. (2) Existing elastic inorganic aerogels often exhibit lower stiffness, but many practical applications demand certain levels of material hardness. Nature has served mankind as a great source of inspiration by virtue of millions of engineered, well-coordinated, and crafted processes, materials, and designs. Nature nacre has a “brick-and-mortar” microstructure and abundant interfacial interactions, showing high fracture toughness and excellent strength. Recently, a mesoscale “assembly-and-mineralization” approach inspired by the layer structure of nacre has been reported to fabricate bulk synthetic nacre with good ultimate strength and toughness [162]. This design provides a new idea for the fabrication of robust composite materials with hierarchically ordered structures, which guide us for investigating elastic inorganic with certain hardness or strength. (3) Current applications of inorganic aerogels lean toward foundational material characterization, thus requiring consideration of the complex performance, mechanics, and device requirements in practical application scenarios. For example, photoactive material with photo-responsiveness could enable on-demand drug administration. Gold nanorods with localized surface plasmon resonance phenomena are one of the most promising plasmonic photothermal therapy agents that could damage cancer cells or bacteria while reducing the risk of damaging healthy cells. Electrospinning shows great potential in the preparation of photoactive materials [163]. Hence, focusing on engineering applications, optimizing the structure and properties of elastic inorganic aerogels, or further compositing with other materials to develop devices with practical value become crucial. This approach should also consider the optimization of material synthesis processes to reduce production costs and time, thereby playing a significant role in advancing the practical utility of elastic inorganic aerogels. References Liu, Y. T.; Ding, B. Ultralight and superelastic ceramic nanofibrous aerogels: A new vision of an ancient material. Sci. Bull. 2023, 68, 753–755. [1] Xu, X.; Zhang, Q. Q.; Hao, M. L.; Hu, Y.; Lin, Z. Y.; Peng, L. L.; Wang, T.; Ren, X. X.; Wang, C.; Zhao, Z. P. et al. Double-negativeindex ceramic aerogels for thermal superinsulation. Science 2019, 363, 723–727. [2] Olsson, R. T.; Azizi Samir, M. A. S.; Salazar-Alvarez, G.; Belova, L.; Ström, V.; Berglund, L. A.; Ikkala, O.; Nogués, J.; Gedde, U. W. Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nanofibrils as templates. Nat. Nanotechnol. 2010, 5, 584–588. [3] Du, R.; Fan, X. L.; Jin, X. Y.; Hübner, R.; Hu, Y.; Eychmüller, A. Emerging noble metal aerogels: State of the art and a look forward. Matter 2019, 1, 39–56. [4] Yan, Z. S.; Liu, X. Y.; Ding, B.; Yu, J. Y.; Si, Y. Interfacial engineered superelastic metal-organic framework aerogels with vander-Waals barrier channels for nerve agents decomposition. Nat. Commun. 2023, 14, 2116. [5] Ziegler, C.; Wolf, A.; Liu, W.; Herrmann, A. K.; Gaponik, N.; Eychmüller, A. Modern inorganic aerogels. Angew. Chem., Int. Ed. [6] 2017, 56, 13200–13221. Xu, X.; Fu, S. B.; Guo, J. R.; Li, H.; Huang, Y.; Duan, X. F. Elastic ceramic aerogels for thermal superinsulation under extreme conditions. Mater. Today 2021, 42, 162–177. [7] Zhuang, L.; Lu, D.; Zhang, J. J.; Guo, P. F.; Su, L.; Qin, Y. B.; Zhang, P.; Xu, L.; Niu, M.; Peng, K. et al. Highly cross-linked carbon tube aerogels with enhanced elasticity and fatigue resistance. Nat. Commun. 2023, 14, 3178. [8] Shi, Q. R.; Zhu, C. Z.; Tian, M. K.; Su, D.; Fu, M. S.; Engelhard, M. H.; Chowdhury, I.; Feng, S.; Du, D.; Lin, Y. H. Ultrafine Pd ensembles anchored-Au2Cu aerogels boost ethanol electrooxidation. Nano Energy 2018, 53, 206–212. [9] Kistler, S. S. Coherent expanded aerogels and jellies. Nature 1931, 127, 741. [10] Gonçalves, W.; Morthomas, J.; Chantrenne, P.; Perez, M.; Foray, G.; Martin, C. L. Elasticity and strength of silica aerogels: A molecular dynamics study on large volumes. Acta Mater. 2018, 145, 165–174. [11] Matter, F.; Luna, A. L.; Niederberger, M. From colloidal dispersions to aerogels: How to master nanoparticle gelation. Nano Today 2020, 30, 100827. [12] Wang, L. B.; Song, G. M.; Qiao, X. X.; Xiong, G.; Liu, Y. M.; Zhang, J. C.; Guo, R. L.; Chen, G. X.; Zhou, Z.; Li, Q. F. Facile fabrication of flexible, robust, and superhydrophobic hybrid aerogel. Langmuir 2019, 35, 8692–8698. [13] Ghica, M. E.; Almeida, C. M. R.; Fonseca, M.; Portugal, A.; Durães, L. Optimization of polyamide pulp-reinforced silica aerogel composites for thermal protection systems. Polymers 2020, 12, 1278. [14] Peng, F.; Jiang, Y. G.; Feng, J.; Cai, H. F.; Feng, J. Z.; Li, L. J. Thermally insulating, fiber-reinforced alumina-silica aerogel composites with ultra-low shrinkage up to 1500 °C. Chem. Eng. J. 2021, 411, 128402. [15] Huang, Y. J.; He, S.; Chen, G. N.; Shi, X. J.; Yang, X. B.; Dai, H. M.; Chen, X. F. Mechanical reinforced fiber needle felt/silica aerogel composite with its flammability. J. Sol-Gel Sci. Technol. 2018, 88, 129–140. [16] Li, J.; Lei, Y.; Xu, D. D.; Liu, F. H.; Li, J. W.; Sun, A. H.; Guo, J. J.; Xu, G. J. Improved mechanical and thermal insulation properties of monolithic attapulgite nanofiber/silica aerogel composites dried at ambient pressure. J. Sol-Gel Sci. Technol. 2017, 82, 702–711. [17] Dou, L. Y.; Cheng, X. T.; Zhang, X. X.; Si, Y.; Yu, J. Y.; Ding, B. Temperature-invariant superelastic, fatigue resistant, and binarynetwork structured silica nanofibrous aerogels for thermal superinsulation. J. Mater. Chem. A 2020, 8, 7775–7783. [18] Woignier, T.; Primera, J.; Alaoui, A.; Etienne, P.; Despestis, F.; Calas-Etienne, S. Mechanical properties and brittle behavior of silica aerogels. Gels 2015, 1, 256–275. [19] Setyawati, M. I.; Tay, C. Y.; Chia, S. L.; Goh, S. L.; Fang, W.; Neo, M. J.; Chong, H. C.; Tan, S. M.; Loo, S. C. J.; Ng, K. W. et al. Titanium dioxide nanomaterials cause endothelial cell leakiness by disrupting the homophilic interaction of VE-cadherin. Nat. Commun. 2013, 4, 1673. [20] Riedle, S.; Wills, J. W.; Miniter, M.; Otter, D. E.; Singh, H.; Brown, A. P.; Micklethwaite, S.; Rees, P.; Jugdaohsingh, R.; Roy, N. C. et al. A murine oral-exposure model for Nano- and microparticulates: Demonstrating human relevance with food-grade titanium dioxide. Small 2020, 16, 2000486. [21] Zhu, Y.; Liu, X. L.; Hu, Y. L.; Wang, R.; Chen, M.; Wu, J. H.; Wang, Y. Y.; Kang, S.; Sun, Y.; Zhu, M. X. Behavior, remediation effect and toxicity of nanomaterials in water environments. Environ. Res. 2019, 174, 54–60. [22] Zhang, M.; Wang, Y.; Zhang, Y. Y.; Song, J.; Si, Y.; Yan, J. H.; Ma, C. L.; Liu, Y. T.; Yu, J. Y.; Ding, B. Conductive and elastic TiO2 nanofibrous aerogels: A new concept toward self-supported electrocatalysts with superior activity and durability. Angew. Chem., Int. Ed. 2020, 59, 23252–23260. [23] Su, L.; Niu, M.; Lu, D.; Cai, Z. X.; Li, M. Z.; Wang, H. J. A review on the emerging resilient and multifunctional ceramic aerogels. J. Mater. Sci. Technol. 2021, 75, 1–13. [24] Quero, F.; Rosenkranz, A. Mechanical performance of binary and[25] 8858 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp ternary hybrid MXene/nanocellulose hydro- and aerogels-a critical review. Adv. Mater. Interfaces 2021, 8, 2100952. Moner-Girona, M.; Martínez, E.; Esteve, J.; Roig, A.; Solanas, R.; Molins, E. Micromechanical properties of carbon-silica aerogel composites. Appl. Phys. A 2002, 74, 119–122. [26] Chang, X. Y.; Cheng, X. T.; Zhang, H.; Li, W. J.; He, L. J.; Yin, X.; Liu, X. Y.; Yu, J. Y.; Liu, Y. T.; Ding, B. Superelastic carbon aerogels: An emerging material for advanced thermal protection in extreme environments. Adv. Funct. Mater. 2023, 33, 2215168. [27] Yan, M. Y.; Cheng, X. D.; Shi, L.; Pan, Y. L.; He, P.; Zhang, Z. X.; Lun, Z.; Fu, Y. Y.; Zhang, H. P. Bioinspired SiC aerogels for super thermal insulation and adsorption with super-elasticity over 100,000 times compressions. Chem. Eng. J. 2023, 455, 140616. [28] Benad, A.; Jürries, F.; Vetter, B.; Klemmed, B.; Hübner, R.; Leyens, C.; Eychmüller, A. Mechanical properties of metal oxide aerogels. Chem. Mater. 2018, 30, 145–152. [29] Rewatkar, P. M.; Taghvaee, T.; Saeed, A. M.; Donthula, S.; Mandal, C.; Chandrasekaran, N.; Leventis, T.; Shruthi, T. K.; Sotiriou-Leventis, C.; Leventis, N. Sturdy, monolithic SiC and Si3N4 aerogels from compressed polymer-cross-linked silica xerogel powders. Chem. Mater. 2018, 30, 1635–1647. [30] Yan, M. Y.; Zhang, H. P.; Fu, Y. Y.; Pan, Y. L.; Lun, Z.; Zhang, Z. X.; He, P.; Cheng, X. D. Implementing an air suction effect induction strategy to create super thermally insulating and superelastic SiC aerogels. Small 2022, 18, 2201039. [31] An, L.; Wang, J. Y.; Petit, D.; Armstrong, J. N.; Hanson, K.; Hamilton, J.; Souza, M.; Zhao, D. H.; Li, C. N.; Liu, Y. Z. et al. An all-ceramic, anisotropic, and flexible aerogel insulation material. Nano Lett. 2020, 20, 3828–3835. [32] Shu, X. F.; Yan, S. C.; Fang, B.; Song, Y. N.; Zhao, Z. J. A 3D multifunctional nitrogen-doped RGO-based aerogel with silver nanowires assisted self-supporting networks for enhanced electromagnetic wave absorption. Chem. Eng. J. 2023, 451, 138825. [33] Li, X.; Zhu, L. T.; Kasuga, T.; Nogi, M.; Koga, H. Frequencytunable and absorption/transmission-switchable microwave absorber based on a chitin-nanofiber-derived elastic carbon aerogel. Chem. Eng. J. 2023, 469, 144010. [34] Deng, Z. J.; Gao, C. Q.; Feng, S.; Zhang, H. F.; Liu, Y. W.; Zhu, Y.; Wang, J. Z.; Xiang, X.; Xie, H. Y. Highly compressible, lightweight and robust Nitrogen-doped graphene composite aerogel for sensitive pressure sensors. Chem. Eng. J. 2023, 471, 144790. [35] Cheng, Y. J.; Sun, X. X.; Yang, S.; Wang, D.; Liang, L.; Wang, S. S.; Ning, Y. H.; Yin, W. L.; Li, Y. B. Multifunctional elastic rGO hybrid aerogels for microwave absorption, infrared stealth and heat insulation. Chem. Eng. J. 2023, 452, 139376. [36] Yang, G. H.; Huang, Z. Z.; McCarthy, A.; Huang, Y. Y.; Pan, J. Y.; Chen, S. X.; Wan, W. B. Super-elastic carbonized mushroom aerogel for management of uncontrolled hemorrhage. Adv. Sci. 2023, 10, 2207347. [37] Xu, X. J.; Wang, R. R.; Nie, P.; Cheng, Y.; Lu, X. Y.; Shi, L. J.; Sun, J. Copper nanowire-based aerogel with tunable pore structure and its application as flexible pressure sensor. ACS Appl. Mater. Interfaces 2017, 9, 14273–14280. [38] Gao, H. L.; Xu, L.; Long, F.; Pan, Z.; Du, Y. X.; Lu, Y.; Ge, J.; Yu, S. H. Macroscopic free-standing hierarchical 3D architectures assembled from silver nanowires by ice templating. Angew. Chem., Int. Ed. 2014, 53, 4561–4566. [39] Jung, S. M.; Preston, D. J.; Jung, H. Y.; Deng, Z. T.; Wang, E. N.; Kong, J. Porous Cu nanowire aerosponges from one-step assembly and their applications in heat dissipation. Adv. Mater. 2016, 28, 1413–1419. [40] Qian, F.; Troksa, A.; Fears, T. M.; Nielsen, M. H.; Nelson, A. J.; Baumann, T. F.; Kucheyev, S. O.; Han, T. Y. J.; Bagge-Hansen, M. Gold aerogel monoliths with tunable ultralow densities. Nano Lett. 2020, 20, 131–135. [41] Yan, P. L.; Brown, E.; Su, Q.; Li, J.; Wang, J.; Xu, C. X.; Zhou, C.; Lin, D. 3D printing hierarchical silver nanowire aerogel with highly compressive resilience and tensile elongation through tunable Poisson’s ratio. Small 2017, 13, 1701756 [42] Qian, F.; Lan, P. C.; Freyman, M. C.; Chen, W.; Kou, T. Y.; Olson,[43] T. Y.; Zhu, C.; Worsley, M. A.; Duoss, E. B.; Spadaccini, C. M. et al. Ultralight conductive silver nanowire aerogels. Nano Lett. 2017, 17, 7171–7176. Zheng, Y. Y.; Yang, J.; Lu, X. B.; Wang, H. L.; Dubale, A. A.; Li, Y.; Jin, Z.; Lou, D. Y.; Sethi, N. K.; Ye, Y. H. et al. Boosting both electrocatalytic activity and durability of metal aerogels via intrinsic hierarchical porosity and continuous conductive network backbone preservation. Adv. Energy Mater. 2021, 11, 2002276. [44] Cheng, X. T.; Liu, Y. T.; Si, Y.; Yu, J. Y.; Ding, B. Direct synthesis of highly stretchable ceramic nanofibrous aerogels via 3D reaction electrospinning. Nat. Commun. 2022, 13, 2637. [45] Guo, F.; Jiang, Y. Q.; Xu, Z.; Xiao, Y. H.; Fang, B.; Liu, Y. J.; Gao, W. W.; Zhao, P.; Wang, H. T.; Gao, C. Highly stretchable carbon aerogels. Nat. Commun. 2018, 9, 881. [46] Wang, H.; Lu, W. B.; Di, J. T.; Li, D.; Zhang, X. H.; Li, M.; Zhang, Z. G.; Zheng, L. X.; Li, Q. W. Ultra-lightweight and highly adaptive all-carbon elastic conductors with stable electrical resistance. Adv. Funct. Mater. 2017, 27, 1606220. [47] Dou, L.; Si, Y.; Yu, J. Y.; Ding, B. Semi-template based, biomimetic-architectured, and mechanically robust ceramic nanofibrous aerogels for thermal insulation. Nano Res. 2022, 15, 5581–5589. [48] Tang, X. W., Zhou, H., Cai, Z. C., Cheng, D. D., He, P. S., Xie, P. W., Zhang, D., Fan, T. X. Generalized 3D printing of graphenebased mixed-dimensional hybrid aerogels. ACS Nano 2018, 12, 3502–3511 [49] Ye, Z. M.; Zhao, B.; Wang, Q.; Chen, K.; Su, M.; Xia, Z. Y.; Han, L.; Li, M.; Kong, X. B.; Shang, Y. Y. et al. Crack-induced superelastic, strength-tunable carbon nanotube sponges. Adv. Funct. Mater. 2023, 33, 2303475. [50] Guo, H. L.; Fei, Q. Y.; Lian, M.; Zhu, T. Y.; Fan, W.; Li, Y. M.; Sun, L.; de Jong, F.; Chu, K. B.; Zong, W. et al. Weaving aerogels into 3D ordered hyperelastic hybrid carbon assemblies. Adv. Mater. 2023, 35, 2301418. [51] Han, L.; Li, X. J.; Li, F. L.; Zhang, H. J.; Liu, X. Y.; Li, G. Q.; Jia, Q. L.; Zhang, S. W. In-situ preparation of SiC reinforced Si3N4 ceramics aerogels by foam-gelcasting method. Ceram. Int. 2022, 48, 1166–1172 [52] Liang, C. Y.; Wang, Z. J. Eggplant-derived SiC aerogels with highperformance electromagnetic wave absorption and thermal insulation properties. Chem. Eng. J. 2019, 373, 598–605. [53] Su, L.; Wang, H. J.; Niu, M.; Dai, S.; Cai, Z. X.; Yang, B. G.; Huyan, H. X.; Pan, X. Q. Anisotropic and hierarchical SiC@SiO2 nanowire aerogel with exceptional stiffness and stability for thermal superinsulation. Sci. Adv. 2020, 6, eaay6689. [54] Liang, X. P.; Shao, Z. J.; Wu, Z.; Wang, J. Y. Flexible SiC nanowire aerogel with excellent thermal insulation properties. Ceram. Int. 2022, 48, 22172–22178. [55] Zong, D. D.; Bai, W. Y.; Yin, X.; Yu, J. Y.; Zhang, S. C.; Ding, B. Gradient pore structured elastic ceramic nanofiber aerogels with cellulose nanonets for noise absorption. Adv. Funct. Mater. 2023, 33, 2301870. [56] Tong, Z. W.; Zhang, B. J.; Yu, H. J.; Yan, X. J.; Xu, H.; Li, X. L.; Ji, H. M. Si3N4 Nanofibrous aerogel with in situ growth of SiOx coating and nanowires for oil/water separation and thermal insulation. ACS Appl. Mater. Interfaces 2021, 13, 22765–22773. [57] Zhang, X. X.; Cheng, X. T.; Si, Y.; Yu, J. Y.; Ding, B. All-ceramic and elastic aerogels with nanofibrous-granular binary synergistic structure for thermal superinsulation. ACS Nano 2022, 16, 5487–5495. [58] Fu, Q. X.; Si, Y.; Duan, C.; Yan, Z. S.; Liu, L. F.; Yu, J. Y.; Ding, B. Highly carboxylated, cellular structured, and underwater superelastic nanofibrous aerogels for efficient protein separation. Adv. Funct. Mater. 2019, 29, 1808234. [59] Zhang, X. X.; Cheng, X. T.; Si, Y.; Yu, J. Y.; Ding, B. Elastic and highly fatigue resistant ZrO2-SiO2 nanofibrous aerogel with low energy dissipation for thermal insulation. Chem. Eng. J. 2022, 433, 133628. [60] Zhang, X.; Liu, C.; Zhang, X. X.; Si, Y.; Yu, J. Y.; Ding, B. Super strong, shear resistant, and highly elastic lamellar structured ceramic nanofibrous aerogels for thermal insulation. J. Mater. Chem. A 2021, 9, 27415–27423. [61] Nano Res. 2024, 17(10): 8842–8862 8859 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research Tang, H.; Gao, P. B.; Bao, Z. H.; Zhou, B.; Shen, J.; Mei, Y. F.; Wu, G. M. Conductive resilient graphene aerogel via magnesiothermic reduction of graphene oxide assemblies. Nano Res. 2015, 8, 1710–1717. [62] Yang, G. C.; Yang, Y. W.; Chen, T. D.; Wang, J. Q.; Ma, L. M.; Yang, S. R. Graphene/MXene composite aerogels reinforced by polyimide for pressure sensing. ACS Appl. Nano Mater. 2022, 5, 1068–1077. [63] Qin, Y. Y.; Peng, Q. Y.; Ding, Y. J.; Lin, Z. S.; Wang, C. H.; Li, Y.; Xu, F.; Li, J. J.; Yuan, Y.; He, X. D. et al. Lightweight, superelastic, and mechanically flexible graphene/polyimide nanocomposite foam for strain sensor application. ACS Nano 2015, 9, 8933–8941. [64] Wang, C. H.; Chen, X.; Wang, B.; Huang, M.; Wang, B.; Jiang, Y.; Ruoff, R. S. Freeze-casting produces a graphene oxide aerogel with a radial and centrosymmetric structure. ACS Nano 2018, 12, 5816–5825. [65] Zhao, J. X.; Zhang, Y.; Zhao, X. X.; Wang, R. T.; Xie, J. X.; Yang, C. F.; Wang, J. J.; Zhang, Q. C.; Li, L. L.; Lu, C. H. et al. Direct ink writing of adjustable electrochemical energy storage device with high gravimetric energy densities. Adv. Funct. Mater. 2019, 29, 1900809. [66] Qiu, L.; Liu, D. Y.; Wang, Y. F.; Cheng, C.; Zhou, K.; Ding, J.; Truong, V. T.; Li, D. Mechanically robust, electrically conductive and stimuli-responsive binary network hydrogels enabled by superelastic graphene aerogels. Adv. Mater. 2014, 26, 3333–3337. [67] Sun, H. Y.; Xu, Z.; Gao, C. Multifunctional, ultra-flyweight, synergistically assembled carbon aerogels. Adv. Mater. 2013, 25, 2554–2560. [68] Li, X. H.; Liu, P. F.; Li, X. F.; An, F.; Min, P.; Liao, K. N.; Yu, Z. Z. Vertically aligned, ultralight and highly compressive allgraphitized graphene aerogels for highly thermally conductive polymer composites. Carbon 2018, 140, 624–633. [69] Lin, Z. Z.; Du, Y. Z.; Chi, C.; Dang, H.; Song, D. X.; Ma, W. G.; Li, Y. S.; Zhang, X. Energy-dependent carrier scattering at weak localizations leading to decoupling of thermopower and conductivity. Carbon 2022, 194, 62–71. [70] Pei, S. F.; Wei, Q. W.; Huang, K.; Cheng, H. M.; Ren, W. C. Green synthesis of graphene oxide by seconds timescale water electrolytic oxidation. Nat. Commun. 2018, 9, 145. [71] Yang, W.; Wang, N. N.; Ping, P.; Yuen, A. C. Y.; Li, A.; Zhu, S. E.; Wang, L. L.; Wu, J.; Chen, T. B. Y.; Si, J. Y. et al. Novel 3D network architectured hybrid aerogel comprising epoxy, graphene, and hydroxylated boron nitride nanosheets. ACS Appl. Mater. Interfaces 2018, 10, 40032–40043. [72] Wang, J. M.; Liu, D.; Li, Q. X.; Chen, C.; Chen, Z. Q.; Song, P. G.; Hao, J.; Li, Y. W.; Fakhrhoseini, S.; Naebe, M. et al. Lightweight, superelastic yet thermoconductive boron nitride nanocomposite aerogel for thermal energy regulation. ACS Nano 2019, 13, 7860–7870. [73] Zeng, X. L.; Ye, L.; Yu, S. H.; Sun, R.; Xu, J. B.; Wong, C. P. Facile preparation of superelastic and ultralow dielectric boron nitride nanosheet aerogels via freeze-casting process. Chem. Mater. 2015, 27, 5849–5855. [74] Yin, J.; Li, X. M.; Zhou, J. X.; Guo, W. L. Ultralight threedimensional boron nitride foam with ultralow permittivity and superelasticity. Nano Lett. 2013, 13, 3232–3236. [75] Li, X.; Dong, G. Q.; Liu, Z. W.; Zhang, X. T. Polyimide aerogel fibers with superior flame resistance, strength, hydrophobicity, and flexibility made via a universal sol–gel confined transition strategy. ACS Nano 2021, 15, 4759–4768. [76] Wen, D.; Liu, W.; Haubold, D.; Zhu, C. Z.; Oschatz, M.; Holzschuh, M.; Wolf, A.; Simon, F.; Kaskel, S.; Eychmüller, A. Gold aerogels: Three-dimensional assembly of nanoparticles and their use as electrocatalytic interfaces. ACS Nano 2016, 10, 2559–2567. [77] Françon, H.; Wang, Z.; Marais, A.; Mystek, K.; Piper, A.; Granberg, H.; Malti, A.; Gatenholm, P.; Larsson, P. A.; Wågberg, L. Ambient-dried, 3D-printable and electrically conducting cellulose nanofiber aerogels by inclusion of functional polymers. Adv. Funct. Mater. 2020, 30, 1909383. [78] Toivonen, M. S.; Kaskela, A.; Rojas, O. J.; Kauppinen, E. I.; Ikkala, O. Ambient-dried cellulose nanofibril aerogel membranes with high tensile strength and their use for aerosol collection and templates for transparent, flexible devices. Adv. Funct. Mater. 2015, 25, 6618–6626. [79] Li, K.; Wang, S. N.; Chen, H.; Yang, X.; Berglund, L. A.; Zhou, Q. Self-densification of highly mesoporous wood structure into a strong and transparent film. Adv. Mater. 2020, 32, 2003653. [80] Hüsing, N.; Schubert, U. Aerogels-airy materials: Chemistry, structure, and properties. Angew. Chem., Int. Ed. 1998, 37, 22–45. [81] Martín-Illán, J. Á.; Rodríguez-San-Miguel, D.; Castillo, O.; Beobide, G.; Perez-Carvajal, J.; Imaz, I.; Maspoch, D.; Zamora, F. Macroscopic ultralight aerogel monoliths of imine-based covalent organic frameworks. Angew. Chem., Int. Ed. 2021, 60, 13969–13977. [82] Hou, X. B.; Zhang, R. B.; Fang, D. N. Novel whisker-reinforced Al2O3-SiO2 aerogel composites with ultra-low thermal conductivity. Ceram. Int. 2017, 43, 9547–9551. [83] Yu, Z. L.; Qin, B.; Ma, Z. Y.; Huang, J.; Li, S. C.; Zhao, H. Y.; Li, H.; Zhu, Y. B.; Wu, H. A.; Yu, S. H. Superelastic hard carbon nanofiber aerogels. Adv. Mater. 2019, 31, 1900651. [84] Kim, K. H.; Tsui, M. N.; Islam, M. F. Graphene-coated carbon nanotube aerogels remain superelastic while resisting fatigue and creep over −100 to +500 °C. Chem. Mater. 2017, 29, 2748–2755. [85] Jung, S. M.; Jung, H. Y.; Fang, W. J.; Dresselhaus, M. S.; Kong, J. A facile methodology for the production of in situ inorganic nanowire hydrogels/aerogels. Nano Lett. 2014, 14, 1810–1817. [86] Bi, H.; Chen, I. W.; Lin, T. Q.; Huang, F. Q. A new tubular graphene form of a tetrahedrally connected cellular structure. Adv. Mater. 2015, 27, 5943–5949. [87] Zhao, J.; Zhang, Y. Z.; Chen, J. Y.; Zhang, W. L.; Yuan, D.; Chua, R.; Alshareef, H. N.; Ma, Y. W. Codoped holey graphene aerogel by selective etching for high-performance sodium-ion storage. Adv. Energy Mater. 2020, 10, 2000099. [88] Yang, H. S.; Li, Z. L.; Lu, B.; Gao, J.; Jin, X. T.; Sun, G. Q.; Zhang, G. F.; Zhang, P. P.; Qu, L. T. Reconstruction of inherent graphene oxide liquid crystals for large-scale fabrication of structure-intact graphene aerogel bulk toward practical applications. ACS Nano 2018, 12, 11407–11416. [89] Yang, H. S.; Jin, X. T.; Sun, G. Q.; Li, Z. L.; Gao, J.; Lu, B.; Shao, C. X.; Zhang, X. Q.; Dai, C. L.; Zhang, Z. P. et al. Retarding ostwald ripening to directly cast 3D porous graphene oxide bulks at open ambient conditions. ACS Nano 2020, 14, 6249–6257. [90] Su, L.; Wang, H. J.; Niu, M.; Fan, X. Y.; Ma, M. B.; Shi, Z. Q.; Guo, S. W. Ultralight, recoverable, and high-temperature-resistant SiC nanowire aerogel. ACS Nano 2018, 12, 3103–3111. [91] Su, L.; Wang, H. J.; Jia, S. H.; Dai, S.; Niu, M.; Ren, J. Q.; Lu, X. F.; Cai, Z. X.; Lu, D.; Li, M. Z. et al. Highly stretchable, crackinsensitive and compressible ceramic aerogel. ACS Nano 2021, 15, 18354–18362. [92] Ren, B.; Liu, J. J.; Rong, Y. D.; Wang, L.; Lu, Y. J.; Xi, X. Q.; Yang, J. L. Nanofibrous aerogel bulk assembled by cross-linked SiC/SiOx core–shell nanofibers with multifunctionality and temperature-invariant hyperelasticity. ACS Nano 2019, 13, 11603–11612. [93] Gui, X. C.; Wei, J. Q.; Wang, K. L.; Cao, A. Y.; Zhu, H. W.; Jia, Y.; Shu, Q. K.; Wu, D. H. Carbon nanotube sponges. Adv. Mater. 2010, 22, 617–621. [94] Aliev, A. E.; Oh, J.; Kozlov, M. E.; Kuznetsov, A. A.; Fang, S. L.; Fonseca, A. F.; Ovalle, R.; Lima, M. D.; Haque, M. H.; Gartstein, Y. N. et al. Giant-stroke, superelastic carbon nanotube aerogel muscles. Science 2009, 323, 1575–1578. [95] Hu, H.; Zhao, Z. B.; Wan, W. B.; Gogotsi, Y.; Qiu, J. S. Ultralight and highly compressible graphene aerogels. Adv. Mater. 2013, 25, 2219–2223. [96] Rawson, S. D.; Bayram, V.; McDonald, S. A.; Yang, P.; Courtois, L.; Guo, Y.; Xu, J. Q.; Burnett, T. L.; Barg, S.; Withers, P. J. Tailoring the microstructure of lamellar Ti3C2Tx MXene aerogel by compressive straining. ACS Nano 2022, 16, 1896–1908. [97] Wang, L.; Zhang, M. Y.; Yang, B.; Tan, J. J.; Ding, X. Y. Highly compressible, thermally stable, light-weight, and robust aramid [98] 8860 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp nanofibers/Ti3AlC2 MXene composite aerogel for sensitive pressure sensor. ACS Nano 2020, 14, 10633–10647. Zhang, H. J.; Lin, C.; Han, T.; Du, F. P.; Zhao, Y. H.; Li, X. P.; Sun, Y. H. Visualization of the formation and 3D porous structure of Ag doped MnO2 aerogel monoliths with high photocatalytic activity. ACS Sustain. Chem. Eng. 2016, 4, 6277–6287. [99] Zhao, J.; Pan, R. J.; Sun, R.; Wen, C. Y.; Zhang, S. L.; Wu, B.; Nyholm, L.; Zhang, Z. B. High-conductivity reduced-grapheneoxide/copper aerogel for energy storage. Nano Energy 2019, 60, 760–767. [100] Zhu, X. Y.; Yang, C.; Wu, P. W.; Ma, Z. Q.; Shang, Y. Y.; Bai, G. Z.; Liu, X. Y.; Chang, G.; Li, N.; Dai, J. J. et al. Precise control of versatile microstructure and properties of graphene aerogel via freezing manipulation. Nanoscale 2020, 12, 4882–4894. [101] Lupi, L.; Hudait, A.; Peters, B.; Grünwald, M.; Mullen, R. G.; Nguyen, A. H.; Molinero, V. Role of stacking disorder in ice nucleation. Nature 2017, 551, 218–222. [102] Freytag, A.; Sánchez-Paradinas, S.; Naskar, S.; Wendt, N.; Colombo, M.; Pugliese, G.; Poppe, J.; Demirci, C.; Kretschmer, I.; Bahnemann, D. W. et al. Versatile aerogel fabrication by freezing and subsequent freeze-drying of colloidal nanoparticle solutions. Angew. Chem., Int. Ed. 2016, 55, 1200–1203. [103] Fears, T. M.; Hammons, J. A.; Sain, J. D.; Nielsen, M. H.; Braun, T.; Kucheyev, S. O. Ultra-low-density silver aerogels via freezesubstitution. APL Mater. 2018, 6, 091103. [104] Zhong, W. B.; Jiang, H. Q.; Yang, L. Y.; Yadav, A.; Ding, X. C.; Chen, Y. L.; Li, M. F.; Sun, G.; Wang, D. Ultra-sensitive piezoresistive sensors constructed with reduced graphene oxide/polyolefin elastomer (RGO/POE) nanofiber aerogels. Polymers 2019, 11, 1883. [105] Alhwaige, A. A.; Herbert, M. M.; Alhassan, S. M.; Ishida, H.; Qutubuddin, S.; Schiraldi, D. A. Laponite/multigraphene hybridreinforced poly(vinyl alcohol) aerogels. Polymer 2016, 91, 180–186. [106] Li, W. L.; Lu, K.; Walz, J. Y. Freeze casting of porous materials: Review of critical factors in microstructure evolution. Int. Mater. Rev. 2012, 57, 37–60. [107] Bai, H.; Chen, Y.; Delattre, B.; Tomsia, A. P.; Ritchie, R. O. Bioinspired large-scale aligned porous materials assembled with dual temperature gradients. Sci. Adv. 2015, 1, e1500849. [108] Deville, S.; Saiz, E.; Nalla, R. K.; Tomsia, A. P. Freezing as a path to build complex composites. Science 2006, 311, 515–518. [109] Zhang, X. X.; Wang, F.; Dou, L.; Cheng, X. T.; Si, Y.; Yu, J. Y.; Ding, B. Ultrastrong, superelastic, and lamellar multiarch structured ZrO2-Al2O3 nanofibrous aerogels with high-temperature resistance over 1300 °C. ACS Nano 2020, 14, 15616–15625. [110] Chen, Z. H.; Zhuo, H.; Hu, Y. J.; Lai, H. H.; Liu, L. X.; Zhong, L. X.; Peng, X. W. Wood-derived lightweight and elastic carbon aerogel for pressure sensing and energy storage. Adv. Funct. Mater. 2020, 30, 1910292. [111] Dong, X. Y.; Cao, L. T.; Si, Y.; Ding, B.; Deng, H. B. Cellular structured CNTs@SiO2 nanofibrous aerogels with vertically aligned vessels for salt-resistant solar desalination. Adv. Mater. 2020, 32, 1908269. [112] Li, C.; Ding, Y. W.; Hu, B. C.; Wu, Z. Y.; Gao, H. L.; Liang, H. W.; Chen, J. F.; Yu, S. H. Temperature-invariant superelastic and fatigue resistant carbon nanofiber aerogels. Adv. Mater. 2020, 32, 1904331. [113] Lu, D.; Niu, M.; Zhuang, L.; Su, L.; Guo, P. F.; Gao, H. F.; Xu, L.; Cai, Z. X.; Li, M. Z.; Peng, K. et al. Strong, superelastic and multifunctional SiC@ pyrolytic carbon nanofibers aerogels. Carbon 2022, 192, 219–226. [114] Si, Y.; Wang, X. Q.; Dou, L.; Yu, J. Y.; Ding, B. Ultralight and fireresistant ceramic nanofibrous aerogels with temperature-invariant superelasticity. Sci. Adv. 2018, 4, eaas8925. [115] Min, P.; Li, X. F.; Liu, P. F.; Liu, J.; Jia, X. Q.; Li, X. P.; Yu, Z. Z. Rational design of soft yet elastic lamellar graphene aerogels via bidirectional freezing for ultrasensitive pressure and bending sensors. Adv. Funct. Mater. 2021, 31, 2103703. [116] Moon, I. K.; Yoon, S.; Chun, K. Y.; Oh, J. Highly elastic and conductive N-doped monolithic graphene aerogels for [117] multifunctional applications. Adv. Funct. Mater. 2015, 25, 6976–6984. Li, C. W.; Jiang, D. G.; Liang, H.; Huo, B. B.; Liu, C. Y.; Yang, W. R.; Liu, J. Q. Superelastic and arbitrary-shaped graphene aerogels with sacrificial skeleton of melamine foam for varied applications. Adv. Funct. Mater. 2018, 28, 1704674. [118] Jiang, D. G.; Zhang, J. Z.; Qin, S.; Wang, Z. Y.; Usman, K. A. S.; Hegh, D.; Liu, J. Q.; Lei, W. W.; Razal, J. M. Superelastic Ti3C2Tx MXene-based hybrid aerogels for compression-resilient devices. ACS Nano 2021, 15, 5000–5010. [119] Zong, D. D.; Cao, L. T.; Yin, X.; Si, Y.; Zhang, S. C.; Yu, J. Y.; Ding, B. Flexible ceramic nanofibrous sponges with hierarchically entangled graphene networks enable noise absorption. Nat. Commun. 2021, 12, 6599. [120] Dou, L.; Zhang, X. X.; Cheng, X. T.; Ma, Z. M.; Wang, X. Q.; Si, Y.; Yu, J. Y.; Ding, B. Hierarchical cellular structured ceramic nanofibrous aerogels with temperature-invariant superelasticity for thermal insulation. ACS Appl. Mater. Interfaces 2019, 11, 29056–29064. [121] Cao, L. T.; Shan, H. R.; Zong, D. D.; Yu, X.; Yin, X.; Si, Y.; Yu, J. Y.; Ding, B. Fire-resistant and hierarchically structured elastic ceramic nanofibrous aerogels for efficient low-frequency noise reduction. Nano Lett. 2022, 22, 1609–1617. [122] Zong, D. D.; Bai, W. Y.; Geng, M.; Yin, X.; Yu, J. Y.; Zhang, S. C.; Ding, B. Bubble templated flexible ceramic nanofiber aerogels with cascaded resonant cavities for high-temperature noise absorption. ACS Nano 2022, 16, 13740–13749. [123] Zhang, Q. Q.; Lin, D.; Deng, B. W.; Xu, X.; Nian, Q.; Jin, S. Y.; Leedy, K. D.; Li, H.; Cheng, G. J. Flyweight, superelastic, electrically conductive, and flame-retardant 3D multi-nanolayer graphene/ceramic metamaterial. Adv. Mater. 2017, 29, 1605506. [124] Zhu, C.; Han, T. Y. J.; Duoss, E. B.; Golobic, A. M.; Kuntz, J. D.; Spadaccini, C. M.; Worsley, M. A. Highly compressible 3D periodic graphene aerogel microlattices. Nat. Commun. 2015, 6, 6962. [125] Guo, P. F.; Su, L.; Peng, K.; Lu, D.; Xu, L.; Li, M. Z.; Wang, H. J. Additive manufacturing of resilient SiC nanowire aerogels. ACS Nano 2022, 16, 6625–6633. [126] Tang, X. W.; Zhou, H.; Cai, Z. C.; Cheng, D. D.; He, P. S.; Xie, P. W.; Zhang, D.; Fan, T. X. Generalized 3D printing of graphenebased mixed-dimensional hybrid aerogels. ACS Nano 2018, 12, 3502–3511. [127] Jiang, Y. Q.; Xu, Z.; Huang, T. Q.; Liu, Y. J.; Guo, F.; Xi, J. B.; Gao, W. W.; Gao, C. Direct 3D printing of ultralight graphene oxide aerogel microlattices. Adv. Funct. Mater. 2018, 28, 1707024. [128] Tetik, H.; Orangi, J.; Yang, G.; Zhao, K. R.; Mujib, S. B.; Singh, G.; Beidaghi, M.; Lin, D. 3D printed MXene aerogels with truly 3D macrostructure and highly engineered microstructure for enhanced electrical and electrochemical performance. Adv. Mater. 2022, 34, 2104980 [129] Kim, K. H.; Oh, Y.; Islam, M. F. Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue. Nat. Nanotechnol. 2012, 7, 562–566. [130] Wang, Z. P.; Wang, Y. S.; Chen, Y. J.; Yousaf, M.; Wu, H. S.; Cao, A. Y.; Han, R. P. S. Reticulate dual-nanowire aerogel for multifunctional applications: A high-performance strain sensor and a high areal capacity rechargeable anode. Adv. Funct. Mater. 2019, 29, 1807467. [131] Si, Y.; Yu, J. Y.; Tang, X. M.; Ge, J. L.; Ding, B. Ultralight nanofibre-assembled cellular aerogels with superelasticity and multifunctionality. Nat. Commun. 2014, 5, 5802. [132] Wan, Y. J.; Zhu, P. L.; Yu, S. H.; Sun, R.; Wong, C. P.; Liao, W. H. Anticorrosive, ultralight, and flexible carbon-wrapped metallic nanowire hybrid sponges for highly efficient electromagnetic interference shielding. Small 2018, 14, 1800534. [133] Dou, L.; Zhang, X. X.; Shan, H. R.; Cheng, X. T.; Si, Y.; Yu, J. Y.; Ding, B. Interweaved cellular structured ceramic nanofibrous aerogels with superior bendability and compressibility. Adv. Funct. Mater. 2020, 30, 2005928. [134] Qiu, L.; Huang, B.; He, Z. J.; Wang, Y. Y.; Tian, Z. M.; Liu, J. Z.; Wang, K.; Song, J. C.; Gengenbach, T. R.; Li, D. Extremely low [135] Nano Res. 2024, 17(10): 8842–8862 8861 www.theNanoResearch.com | www.Springer.com/journal/12274 | Nano Research density and super-compressible graphene cellular materials. Adv. Mater. 2017, 29, 1701553. Zhuo, H.; Hu, Y. J.; Tong, X.; Chen, Z. H.; Zhong, L. X.; Lai, H. H.; Liu, L. X.; Jing, S. S.; Liu, Q. Z.; Liu, C. F. et al. A supercompressible, elastic, and bendable carbon aerogel with ultrasensitive detection limits for compression strain, pressure, and bending angle. Adv. Mater. 2018, 30, 1706705. [136] Gao, H. L.; Zhu, Y. B.; Mao, L. B.; Wang, F. C.; Luo, X. S.; Liu, Y. Y.; Lu, Y.; Pan, Z.; Ge, J.; Shen, W. et al. Super-elastic and fatigue resistant carbon material with lamellar multi-arch microstructure. Nat. Commun. 2016, 7, 12920. [137] Yang, M.; Zhao, N. F.; Cui, Y.; Gao, W. W.; Zhao, Q.; Gao, C.; Bai, H.; Xie, T. Biomimetic architectured graphene aerogel with exceptional strength and resilience. ACS Nano 2017, 11, 6817–6824. [138] Long, S. S.; Feng, Y. C.; He, F. L.; Zhao, J. Z.; Bai, T.; Lin, H. B.; Cai, W. L.; Mao, C. W.; Chen, Y. H.; Gan, L. H. et al. Biomassderived, multifunctional and wave-layered carbon aerogels toward wearable pressure sensors, supercapacitors and triboelectric nanogenerators. Nano Energy 2021, 85, 105973. [139] Xu, X.; Zhang, Q. Q.; Yu, Y. K.; Chen, W. L.; Hu, H.; Li, H. Naturally dried graphene aerogels with superelasticity and tunable Poisson’s ratio. Adv. Mater. 2016, 28, 9223–9230. [140] Li, G. Y.; Zhu, M. Y.; Gong, W. B.; Du, R.; Eychmüller, A.; Li, T. T.; Lv, W. B.; Zhang, X. T. Boron nitride aerogels with superflexibility ranging from liquid nitrogen temperature to 1000 °C. Adv. Funct. Mater. 2019, 29, 1900188. [141] Sun, J. Z.; Du, H.; Chen, Z. J.; Wang, L. L.; Shen, G. Z. MXene quantum dot within natural 3D watermelon peel matrix for biocompatible flexible sensing platform. Nano Res. 2022, 15, 3653–3659. [142] Wu, C. X.; Zhang, Z. F.; Chen, Z. H.; Jiang, Z. M.; Li, H. Y.; Cao, H. J.; Liu, Y. S.; Zhu, Y. Y.; Fang, Z. B.; Yu, X. R. Rational design of novel ultra-small amorphous Fe2O3 nanodots/graphene heterostructures for all-solid-state asymmetric supercapacitors. Nano Res. 2021, 14, 953–960. [143] Zhu, S.; Ni, J. F.; Li, Y. Carbon nanotube-based electrodes for flexible supercapacitors. Nano Res. 2020, 13, 1825–1841. [144] Afroze, J. D.; Tong, L. Y.; Abden, M. J.; Yuan, Z. W.; Chen, Y. Hierarchical honeycomb graphene aerogels reinforced by carbon nanotubes with multifunctional mechanical and electrical properties. Carbon 2021, 175, 312–321. [145] Zhang, Q. Q.; Wang, Y.; Zhang, B. Q.; Zhao, K. R.; He, P. G.; Huang, B. Y. 3D superelastic graphene aerogel-nanosheet hybrid hierarchical nanostructures as high-performance supercapacitor electrodes. Carbon 2018, 127, 449–458 [146] Im, H.; Kim, T.; Song, H.; Choi, J.; Park, J. S.; Ovalle-Robles, R.; Yang, H. D.; Kihm, K. D.; Baughman, R. H.; Lee, H. H. et al. Highefficiency electrochemical thermal energy harvester using carbon nanotube aerogel sheet electrodes. Nat. Commun. 2016, 7, 10600. [147] Shang, T. X.; Lin, Z. F.; Qi, C. S.; Liu, X. C.; Li, P.; Tao, Y.; Wu, Z. T.; Li, D. W.; Simon, P.; Yang, Q. H. 3D macroscopic architectures from self-assembled MXene hydrogels. Adv. Funct. Mater. 2019, 29, 1903960. [148] An, L.; Armstrong, J. N.; Hu, Y.; Huang, Y. L.; Li, Z.; Zhao, D. H.; Sokolow, J.; Guo, Z. P.; Zhou, C.; Ren, S. Q. High temperature ceramic thermal insulation material. Nano Res. 2022, 15, 6662–6669. [149] Hu, F.; Wu, S. Y.; Sun, Y. G. Hollow-structured materials for thermal insulation. Adv. Mater. 2019, 31, 1801001. [150] Wang, F.; Dou, L.; Dai, J. W.; Li, Y. Y.; Huang, L. Q.; Si, Y.; Yu, J. Y.; Ding, B. In situ synthesis of biomimetic silica nanofibrous aerogels with temperature-invariant superelasticity over one million compressions. Angew. Chem., Int. Ed. 2020, 59, 8285–8292. [151] Zhang, E. S.; Zhang, W. L.; Lv, T.; Li, J.; Dai, J. X.; Zhang, F.;[152] Zhao, Y. M.; Yang, J. Y.; Li, W. J.; Zhang, H. Insulating and robust ceramic nanorod aerogels with high-temperature resistance over 1400 °C. ACS Appl. Mater. Interfaces 2021, 13, 20548–20558. Yang, H. S.; Li, Z. L.; Sun, G. Q.; Jin, X. T.; Lu, B.; Zhang, P. P.; Lin, T. Y.; Qu, L. T. Superplastic air-dryable graphene hydrogels for wet-press assembly of ultrastrong superelastic aerogels with infinite macroscale. Adv. Funct. Mater. 2019, 29, 1901917. [153] Yu, H. J.; Tong, Z. W.; Zhang, B. J.; Chen, Z. W.; Li, X. L.; Su, D.; Ji, H. M. Thermal radiation shielded, high strength, fire resistant fiber/nanorod/aerogel composites fabricated by in-situ growth of TiO2 nanorods for thermal insulation. Chem. Eng. J. 2021, 418, 129342. [154] Li, J. J.; Yang, S.; Jiao, P. Z.; Peng, Q. Y.; Yin, W. L.; Yuan, Y.; Lu, H. B.; He, X. D.; Li, Y. B. Three-dimensional macroassembly of hybrid C@CoFe nanoparticles/reduced graphene oxide nanosheets towards multifunctional foam. Carbon 2020, 157, 427–436. [155] Meng, X. Y.; Peng, X. L.; Wei, Y.; Ramakrishna, S.; Sun, Y. M.; Dai, Y. Q. Smart-simulation derived elastic 3D fibrous aerogels with rigid oxide elements and all-in-one multifunctions. Chem. Eng. J. 2022, 437, 135444. [156] Jin, X.; Al-Qatatsheh, A.; Subhani, K.; Salim, N. V. Biomimetic and flexible 3D carbon nanofiber networks with fire-resistant and high oil-sorption capabilities. Chem. Eng. J. 2021, 412, 128635. [157] Wang, C. H.; He, X. D.; Shang, Y. Y.; Peng, Q. Y.; Qin, Y. Y.; Shi, E. Z.; Yang, Y. B.; Wu, S. T.; Xu, W. J.; Du, S. Y. et al. Multifunctional graphene sheet-nanoribbon hybrid aerogels. J. Mater. Chem. A 2014, 2, 14994–15000. [158] Dong, X. Y.; Si, Y.; Chen, C. J.; Ding, B.; Deng, H. B. Reed leaves inspired silica nanofibrous aerogels with parallel-arranged vessels for salt-resistant solar desalination. ACS Nano 2021, 15, 12256–12266. [159] Kang, W. W.; Cui, Y.; Qin, L.; Yang, Y. Z.; Zhao, Z. B.; Wang, X. Z.; Liu, X. G. A novel robust adsorbent for efficient oil/water separation: Magnetic carbon nanospheres/graphene composite aerogel. J. Hazard. Mater. 2020, 392, 122499. [160] Zhao, X. L.; Yao, W. Q.; Gao, W. W.; Chen, H.; Gao, C. Wet-spun superelastic graphene aerogel millispheres with group effect. Adv. Mater. 2017, 29, 1701482. [161] Mao, L. B.; Gao, H. L.; Yao, H. B.; Liu, L.; Cölfen, H.; Liu, G.; Chen, S. M.; Li, S. K.; Yan, Y. X.; Liu, Y. Y. et al. Synthetic nacre by predesigned matrix-directed mineralization. Science 2016, 354, 107–110. [162] Bayan, M. A. H.; Dias, Y. J.; Rinoldi, C.; Nakielski, P.; Rybak, D.; Truong, Y. B.; Yarin, A. L.; Pierini, F. Near-infrared light activated core-shell electrospun nanofibers decorated with photoactive plasmonic nanoparticles for on-demand smart drug delivery applications. J. Polym. Sci. 2023, 61, 521–533. [163] Zhang, M.; Yang, D. Z.; Zhang, S. Y.; Xu, T.; Shi, Y. Z.; Liu, Y. X.; Chang, W.; Yu, Z. Z. Elastic and hierarchical carbon nanofiber aerogels and their hybrids with carbon nanotubes and cobalt oxide nanoparticles for high-performance asymmetric supercapacitors. Carbon 2020, 158, 873–884. [164] Kang, S.; Qiao, S. Y.; Cao, Y. T.; Hu, Z. M.; Yu, J. R.; Wang, Y. Compression strain-dependent tubular carbon nanofibers/graphene aerogel absorber with ultrabroad absorption band. Chem. Eng. J. 2022, 433, 133619. [165] Zou, J. H.; Liu, J. H.; Karakoti, A. S.; Kumar, A.; Joung, D.; Li, Q.; Khondaker, S. I.; Seal, S.; Zhai, L. Ultralight multiwalled carbon nanotube aerogel. ACS Nano 2010, 4, 7293–7302. [166] Lu, D.; Su, L.; Wang, H. J.; Niu, M.; Xu, L.; Ma, M. B.; Gao, H. F.; Cai, Z. X.; Fan, X. Y. Scalable fabrication of resilient SiC nanowires aerogels with exceptional high-temperature stability. ACS Appl. Mater. Interfaces 2019, 11, 45338–45344. [167] 8862 Nano Res. 2024, 17(10): 8842–8862 | www.editorialmanager.com/nare/default.asp
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