Fuel Cell Membranes Based on Polymer-Modified Silica Colloidal Crystals and Glasses: Proton Conductivity and Fuel Cell Performance

Abstract

We describe a hybrid organic-inorganic fuel cell membrane material based on silica colloidal crystal and using EEMA/SPM co-polymers. We demonstrate that there is an S-shaped dependence of proton conductivity on the amount of sulfonyl groups in the copolymer for the copolymer-modified membranes and that there is no significant increase in proton conductivity with increasing amount of sulfonated monomer content above 60%. The studies of fuel cell potential dependence on the degree of sulfonation show that the presence of non-ionic moieties improves the performance of fuel cell, likely due to the reduction of methanol cross-over through the membrane. The fuel cells using the polymer-modified silica colloidal membranes perform better than Nafion 117.