Improvement of Surface Proton Conductivity for Three-Dimensionally Ordered Macroporous Silica Membrane

Direct methanol fuel cells (DMFCs) have been expected as portable power sources for various kinds of mobile tools because they can utilize methanol without reforming equipment of methanol to hydrogen. However, DMFC has some problems for practical applications. For example, it is necessary to restrain methanol cross-over caused by swelling of ion exchange membrane. Crossover leads to a voltage drop of fuel cell and lowers fuel utilization. Recently, we reported a composite electrolyte membrane prepared by using an ordered porous silica membrane whose pores were filled by gel polymer electrolyte. It exhibited an excellent low methanol cross-over due to a 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.