Proton conductivity and performance in fuel cells of grafted membranes based on polymethylpentene with radiation-grafted crosslinked sulfonated polystyrene

摘要

In this work, a comparative study was carried out of the transport properties and performance in a hydrogen-air fuel cell of the membranes based on polymethylpentene (PMP) with grafted sulfonated polystyrene and the standard Nafion (R) 212 membrane. Grafted cation-exchange membranes (GCM) were obtained by radiation graft post-polymerization of styrene onto UV-exposed PMP film followed by sulfonation with chlorosulfonic acid. The proton-conductivity of the GCM membrane with an ion-exchange capacity of 2.9 +/- 0.1 meq/g reaches 21 +/- 1 mS cm(-1) at room temperature and 95% relative humidity, which is twice higher the conductivity of the Nafion (R) under the same conditions. The GCM-1 H-2-permeability of 2.06.10(-7) cm(2) s(-1) even slightly lower than that of the Nafion (R) 212 (2.14.10(-7) cm(2) s(-1)). A comparison of these membranes in the membrane electrode assemblies (MEA) of hydrogen-air fuel cells (FC) shows that the use of the grafted membranes with the high ion-exchange capacity is highly promising. The maximum performance of FC with grafted and Nafion (R) 212 membrane are both close to 180 mW/cm(2) at the current density of 400 mA/cm(2). At the same time, the high degree of crosslinking of sulfonated polystyrene leads to a decrease in conductivity and does not give an advantage in gas permeability. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.