Preparing proton exchange membranes via incorporating silica-based nanoscale ionic materials for the enhanced proton conductivity

Proton exchange membranes (PEMs) have triggered growing attention in energy-related applications due to their fundamental and technological significance. In this work, silica-based nanoscale ionic materials (NIMs-SiO2) were synthesized and incorporated into sulfonated poly (ether-ether-ketone) (SPEEK) to prepare nanocomposite membranes. NIMs-SiO2 could not only provide extra proton transfer sites, but also enhanced the hydrophilicity of the membranes, leading to decrease of the activation energy. The nano-scale size (7 nm) and the functional groups of the NIMs-SiO2 lead to good interfacial adhesion with SPEEK, improving the mechanical properties of the membranes. Consequently, SPEEK/NIMs-SiO2 (5) exhibited the highest proton conductivity and peak power density, which were 1.92 and 1.51 folds higher than the pristine SPEEK membranes, respectively. The results showed the nanocomposite membranes had potential as alternative proton exchange membranes for corresponding devices.