Relaxation phenomena and conductivity mechanisms in anion-exchange membranes derived from polyketone
| Autor: | Angeloclaudio Nale, Fosca Conti, Vito Di Noto, Gianni Cavinato, Gioele Pagot, Yannick Herve Bang, Keti Vezzù, Enrico Negro, Graeme Nawn |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
General Chemical Engineering 02 engineering and technology Dielectric Conductivity 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Ion Delocalized electron Membrane Chemical physics Polyketone Percolation Electrochemistry Relaxation (physics) 0210 nano-technology |
| Popis: | A polyketone-b-poly[N-(4 methyl-methylpyridium)-ethylenepyrrole+][X−], with X− = I− or OH−, is investigated as an example of anion-exchange membrane with potential applications in fuel cells. The polyketone starting material PK and the functionalized polyketones Pyr-FPKmI and Pyr-FPKmOH are investigated via Broadband Electrical Spectroscopy (BES) to understand the conductivity mechanism. BES signals are collected in the frequency range of 10−2 – 107 Hz and from −100° to 120 °C. BES measurements reveal the presence of up to three interdomain polarizations phenomena, one electrode polarization event and two β dielectric relaxation modes for both wet Pyr-FPKmI and Pyr-FPKmOH. Ion conductivity for Pyr-FPKmI and Pyr-FPKmOH is found to be 0.0086 and 0.0105 S cm−1 at 80 °C, respectively. The overall conductivity mechanism is attributed to the superposition of two conduction pathways, via delocalization bodies and via interdomain percolation pathways, which are associated with two different physical phenomena. |
| Databáze: | OpenAIRE |
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