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

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

Keywords:

Copolymer sulfonated graphene oxide-poly(styrene divinylbenzene)–polyethylene , Polymer electrolyte membrane , Methanol permeability , Iionic conductivity