Chemical modification of cation exchanger poly(styrene divinylbenzene) with sulfonated graphene oxide for proton coduction

A novel polymer electrolyte membrane has been prepared using copolymer sulfonated graphene oxide-poly(styrene divinylbenzene)–polyethylene (SGO-SPSD-PE). The membrane is characterized by FT-IR and SEM. Oxidative resistance, water uptake, ionic conductivity and methanol permeability are measured to evaluate its performance in a direct methanol fuel cell with cation exchanger membrane. The membranes were confirmed to retain 1–5% water vapour at 80–140 °C in air due to the hydrophilic of highly SPSD and SGO. The ionic conductivity and permeability of the membrane to methanol was found to increase with temperature increasing. The membrane SGO-SPSD–PE shows the proton conductivity of 2.74 × 10-2 S cm-1 at 100 °C without extra humidity supply and is very promising for high temperature with low humidity. The high proton conductivity is ascribed to the unique composition in which the heterocyclic polymer provides the proton motion by construction diffusion and the highly SGO-SPSD copolymer retains water vapour to lower the activation energy for proton conduction.