Journal: Materials

Article Title: Insights in the Ionic Conduction inside Nanoporous Metal-Organic Frameworks by Using an Appropriate Equivalent Circuit

doi: 10.3390/ma14164352

Figure Lengend Snippet: IL@HKUST-1. ( a ) Structure of IL of type [BMIM][TFSI] in HKUST-1 ( b ) and ( c ) Nyquist plots for the sample in the form of a MOF-pellet sandwiched between 2 gold electrodes ( b ), and in the form of a thin film on a glass substrate with interdigitated gold electrodes ( c ). The IL pore fillings are 50%, 80%, 95%, and 100%, as indicated. The black lines are the fits with the ( R-CPE dl )‖ CPE geo circuit. The frequency range is 100 Hz to 5 MHz ( b ), and 0.5 Hz to 5 MHz ( c ). Please note, for better visibility, the impedance values for 100%-loading in panel ( c ) are divided by 4, to allow the presentation in the same plot. The SURMOF sample was 0.25 µm thick, deposited on a substrate with IDEs of 10 µm gap distance and a total gap length of 1.69 m. The data of panel ( c ) are taken from with copyright permission from 2019 American Chemical Society.

Article Snippet: The substrates are glass sheets with deposited interdigitated gold electrodes (IDEs), obtained from DropSens (Metrohm DropSens, Oviedo, Spain).

Techniques:

Journal: Materials

Article Title: Insights in the Ionic Conduction inside Nanoporous Metal-Organic Frameworks by Using an Appropriate Equivalent Circuit

doi: 10.3390/ma14164352

Figure Lengend Snippet: Nyquist plots for the IL@HKUST-1 in the form of a thin film on a glass substrate with interdigitated gold electrodes, see c. The experimental data are shown as spheres, the grey-dotted lines are the fits with the ( R-CPE dl )‖ CPE geo circuit (same data as in c). The black-color-dashed lines are the best fits by Randles equivalent circuit. The IL pore fillings are 50%, 80%, 95%, and 100%, as indicated. The frequency range in panel ( a ) is 0.5 Hz to 5 MHz, and in panel ( b ) is 107 Hz to 5 MHz. Only the plotted data are used for the fitting by the models. Like in , the major reason for the poor description of the experimental data by the Randles circuit is the fact that the Warburg resistance of the Randles circuit results in a low-frequency ray with an angle of 45° in the Nyquist plots, which is often not the case in the experimental data. This results in poor fits, especially when the EIS data at the low-frequency range is recorded—see panel ( a ).

Article Snippet: The substrates are glass sheets with deposited interdigitated gold electrodes (IDEs), obtained from DropSens (Metrohm DropSens, Oviedo, Spain).

Techniques:

Journal: Materials

Article Title: Insights in the Ionic Conduction inside Nanoporous Metal-Organic Frameworks by Using an Appropriate Equivalent Circuit

doi: 10.3390/ma14164352

Figure Lengend Snippet: Nyquist plots of IL [BMIM][TFSI] in HKUST-1 SURMOF films. The SURMOF films are grown on the IDE substrates, whose surface has been treated in different ways before the SURMOF synthesis: One substrate has an OH-terminated MUD-SAM (green), one has a COOH-terminated MHDA-SAM (red) and one substrate was exposed to UV-ozone for 30 min before the SURMOF synthesis (blue). The black lines are the fits with the ( R-CPE dl )‖ CPE geo circuit, where the parameters are shown in . The substrates are glass sheets with IDEs of 10 µm gap distance and a total gap length of 1.69 m. The area of each electrode is approximately 17 mm 2 . The frequency range is 3.5 Hz to 5 MHz.

Article Snippet: The substrates are glass sheets with deposited interdigitated gold electrodes (IDEs), obtained from DropSens (Metrohm DropSens, Oviedo, Spain).

Techniques: