Preparation and properties of PVC-PVP composite high temperature proton exchange membranes reinforced with PTFE for high temperature fuel cells

Proton exchange membrane fuel cell (PEMFC) operating above 100℃ can overcome the defects of low temperature operation, improve the ability of platinum catalyst to resist CO poisoning, accelerate electrode kinetics, simplify hydrothermal management system and improve heat recycling. In order to achieve both high proton conductivity and excellent mechanical properties of phosphoric acid (PA)-doped high temperature Proton exchange membrane (HT-PEM), we prepared a series of polytetrafluoroethylene (PTFE^®)-reinforced polyvinylpyrrolidone-polyvinyl chloride (PVP-PVC) composite membranes. By adjusting the ratio of PVP and PVC, the best composite membrane was found, and its physical and chemical properties were tested and characterized. SEM results showed that PVP-PVC was uniformly filled into the pores of PTFE^® membrane without bubbles and holes. The results of proton conductivity and mechanical property test show that PTFE^® enhanced membrane has good tensile strength and dimensional stability, and the proton conductivity increases with the increase of PVP content in the composite membrane. As a result, the proton conductivity of PA-doped PTFE^® reinforced composite membrane i.e. the mass ratio of PVP to PVC is 4 is as high as 0.161 S·cm⁻¹ at 160℃, and the maximum tensile strength of the membrane at room temperature is 15.6 MPa. At 160℃, the peak power density of the composite membrane is about 359 mW·cm⁻². These results indicate that PA-doped PTFE-reinforced composite membranes have the potential to be used as HT-PEM.