High temperature ceramic proton exchange membranes for direct methanol fuel cells

A novel inorganic proton exchange membrane based on H₃PW ₁₂O₄₀ (HPW)/MCM-41 mesoporous silica nanocomposites was successfully prepared by a simple vacuum-assisted impregnation method (VIM). The VIM-assembled HPW/MCM-41 electrolyte has a high proton conductivity of 0.018 and 0.045 Scm^-1 at 25 and 150°C, respectively. Single fuel cells based on VIM-30wt%HPW/MCM-41 composite membranes produced a peak power density of 95 mWcm^-2 at 100°C and 100% RH in H₂/O₂ and 90 mWcm^-2 at 150°C and a low relative humidy of 0.67%. The results demonstrate for the first time that the VIM-assembled HPW/MCM-41 mesoporous silica can be used as effective proton exchange membrane for elevated high temperature PEMFCs and DMFCs.