Hybrid polyelectrolytes based on stable sulfonated polynorbornene with higher proton conductivity and lower methanol permeability

Hybrid cross-linked membranes based sulfonated copoly(norbornene)s bearing sultone pendant and a zwitterionic silica are synthesized by sol-gel method. The membranes possess good stabilities, high proton conductivity up to 6.34 × 10−2 S cm−1 and comparable selectivity parameter. A maximum power density of 50.2 mW cm−2 is achieved for direct methanol fuel cells.