Investigation of proton conductivity in polymer nanocomposite films*

Proton-conducting membranes and solid electrolytes are critical components in many electrochemical devices, and the performance of such devices is often limited by proton transport. In this work, we study proton conductivity in polymer nanocomposite films. We experimentally observe multifold increase in proton conductivity in a composite of poly(ethylene oxide) (PEO) and cerium oxide (CeO₂) nanocrystals, in comparison to their individual counterparts. Employing kinetic Monte Carlo simulations, we model proton transport in such systems. Our results reveal the significance of percolation and connectivity of filler/polymer interface in such systems, with further scope for improving conductivity by tuning the morphology of nanocrystals. We also study the overall proton conductivity at different nanocrystal compositions, predicting an optimum composition for maximum proton conductivity.