Phosphorylated poly(ethylene-co-vinyl alcohol) doping for enhanced proton conductivity and mechanical properties of side chain–type sulfonated poly(aryl ether ketone) proton-exchange membranes

Phosphorylated poly (ethylene-co-vinyl alcohol) (PEVOH) was synthesized and blended with side chain–type sulfonated poly (aryl ether ketone) (SPAEK) to prepare SPAEK proton-exchange membranes with improved physicochemical and electrochemical properties. The results indicate that PEVOH doping helps improve the mechanical properties and proton conductivity of the membranes. The addition of PEVOH not only enhances proton transport but also provides proton transport channels for the membranes at a high temperature and low humidity, leading to excellent fuel cell performance and low ohmic resistance. The interaction between sulfonic acid and phosphonic acid side chain groups leads to the excellent nano-phase separation under microscopic morphology. This forms a large hydrogen bonding network between the acidic and amphoteric groups, which facilitates proton transport at low relative humidities.