On-site crosslinked quaternized poly(vinyl alcohol) as ionomer binder for solid alkaline fuel cells

Water-soluble polyvinyl alcohol functionalized with quaternary ammonium groups and crosslinked quatemized polyvinyl alcohol were synthesized and used to prepare an ionomer binder solution having a low boiling point and high dielectric constant solvent to be used in electrodes for solid alkaline fuel cells. The polyvinyl alcohol was quatemized to have anion-conducting ability using glycidyltrimethylammonium chloride. To prevent washing-out of the water-soluble anion-conducting ionomer during fuel cell operations, the quatemized poly(vinyl alcohol) was successfully crosslinked by using an on-site crosslinking method. The highest ionic conductivity of the ionomer was 2.3 x 10(-2) S cm(-1), and its ion exchange capacity was 1.2 meq g(-1) at room temperature. The electrodes were fabricated by a spray method on anion-exchangeable membranes, and membraneelectrode assemblies were operated at 50 degrees C in ambient pressure and were characterized by voltage-current relationship and cyclic voltammetry. The highest performance of the membrane-electrode assemblies having the electrode with the ionomer of 25 wt.% in dry weight basis was 172.8 mW cm(-2) at 0.485 V. As a result, the anionic binder electrodes introduced by the on-site crosslinking were successfully functioned both to conduct OH ions between electrodes and an electrolyte and to move electron to an external circuit by forming three phase boundary at the electrode of the membrane-electrode assemblies. Copyright (C), 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.