Review on proton conducting membrane for PEM water electrolyser: A sustainable approach for green hydrogen production

Abstract

Water electrolysis with proton exchange membranes (PEMs) holds great promise for producing green hydrogen, but the industry still leans heavily on expensive perfluorosulfonic acid membranes like Nafion. In this review, we dive into both established PFSA materials (Nafion, Aquivion, and PFSA–polymer composites) and emerging hydrocarbon-based alternatives (sulfonated poly(arylene ether sulfone), sulfonated poly(ether ether ketone), polyphenylene sulfone, and related systems). Rather than merely listing developments, we uncover how modifications at the molecular level-backbone chemistry, side-chain length, reinforcement by inorganic fillers, and crosslinking- translate into real gains in proton conductivity, mechanical strength, and chemical resilience. We also examine how these membranes behave under the harsh, acidic conditions of a working PEM water electrolyser, pinpointing the main pathways of performance loss (delamination, excessive swelling, and chemical degradation). Drawing on the latest studies, we highlight novel composite strategies-such as hybrid organic–inorganic networks and graft-copolymer architectures-that bring hydrocarbon membranes closer to PFSA benchmarks, often at dramatically lower cost. Finally, we sketch out future directions: designing acid-stable ion channels, refining scalable synthesis techniques, and integrating advanced reinforcement approaches to bridge the gap between lab-scale promise and industrial reality. By illuminating these structure–property links and proposing targeted research avenues, this review charts a clear path toward affordable, high-performance PEMs for a truly sustainable hydrogen economy.