Improvement on Proton Conductivity of Porous Silica/Gel Composite Electrolyte Membrane by Surface Sulfonation Method

Abstract

A direct methanol fuel cell (DMFC) has been expected as promising power sources for mobile and stationary applications. For practical applications of DMFC, however, it is necessary to restrain methanol cross-over caused by swelling of ion exchange membrane. We reported a composite electrolyte membrane consisting of gel electrolyte and three-dimensionally ordered silica matrix, which exhibited a low methanol cross-over due to the suppression of polymer expansion by the silica matrix. It is well known that silanol groups (Si-OH) react with various organosilane compounds. So, one can introduce desired properties on glass surfaces. In this study, we developed new conductive path for protons by surface modification of porous silica membrane and optimized its reaction condition.