Molecular engineering of organic-inorganic interface towards high-performance polyelectrolyte membrane via amphiphilic block copolymer

Fast proton transport, good stability and high fuel-blocking property in solid polyelectrolytes is of critical significance for a number of energy-conversion devices. However, the simultaneous enhancement of these properties has proved to be extremely challenging. Herein, we report a novel strategy to remarkably increase the comprehensive properties of Nafion-based mixed-matrix polyelectrolyte membranes through engineering organic-inorganic interfaces using amphiphilic block copolymer functionalized nanoparticles, SiO2 nanoparticles grafted with sulfonated polystyrene-b-polyperfluroallylbenzene. The amphiphilic block copolymer on nanoparticles imparts favorable interactions between the nanoparticles and amphiphilic Nafion, and thus facilitates the dispersion of nanoparticles and the reorganization of ion clusters. As a result, the mixed-matrix polyelectrolyte membrane with 2.5 wt% filler loading exhibits proton conductivities of 327 mS cm−1 at 80 °C, 100% RH, and 63 mS cm−1 at 80 °C, 50% RH, which is one of the highest proton conductivities ever reported. Moreover, the membrane also shows pronounced enhancements in thermal stability, dimensional stability, methanol-blocking property, and mechanical strength, in comparison with those of Nafion.