Mitigating Hydrogen Crossover in Proton Exchange Membranes by integrating 2D materials

Abstract

Conventional proton exchange membranes (PEMs) used in PEM fuel cells conduct protons efficiently while preventing hydrogen from crossing over from the anode to the cathode. However, reducing hydrogen crossover often leads to increased resistance or mechanical instability. In this work, polytetrafluoroethylene (PTFE) reinforced perfluorosulfonic acid (PFSA) membrane (Nafion HP) was used as a stable platform to integrate an atomically thin graphene layer aimed at improving gas barrier properties without compromising proton transport. Graphene was incorporated in single layer and sandwich configurations within the membrane structure, and the resulting membranes were evaluated using electrochemical measurements. The performance was directly compared with conventional, non-reinforced PEMs such as Nafion N211 to assess relative improvements. The graphene integrated Nafion HP membranes showed 30% reduction in hydrogen crossover while maintaining similar ionic resistance and overall cell performance compared to both their reinforced controls and conventional N211 membranes which shows 30-50% crossover reduction. These findings demonstrate that combining reinforced PEMs with ultrathin two-dimensional materials can improve transport selectivity, offering an alternate route to enhancing fuel cell efficiency without introducing major performance tradeoffs.