Synthesis of highly stable PTFE-ZrP-PVA composite membrane for high-temperature direct methanol fuel cell

Abstract

A composite membrane was synthesized by functionalizing the Polytetrafluoroethylene film with inorganic Zirconium Phosphate and polyvinyl alcohol. The hybrid method of pore infiltration and layer by layer coating was adopted to obtain the membrane. Hydrophilicity of the PTFE support was increased by chemical treatment. The proton conductivity of the membrane was increased considerably by using chemically treated hydrophilic support. The composition of ZrP and PVA in the solution (sol) was optimized with respect to methanol crossover and proton conductivity. The top view of the membrane surface morphology was observed by using SEM and EDX revealed the presence of 31.9% Zirconium and 26.44% Phosphate in the synthesized membrane. The membrane top layer functional groups were analyzed by FT-IR and the spectra confirm the incidence of functional groups related to ZrP and PVA. Thermal stability of the membrane was analyzed using TGA-DTA and it was stable up to 140 °C. The membrane was mechanically stabile with a mechanical strength of 44 MPa. The membrane possessed proton conductivity of 28.1 mS cm−1 and low methanol permeability (14.5 × 10-7 cm2 s−1) at 80 °C.