Recent Development and Challenges of Bipolar Membranes for High Performance Water Electrolysis

Bipolar membranes (BPMs) are a class of special ion exchange membranes consisting of a cation-exchange layer (CEL) and an anion-exchange layer (AEL). BPMs can selectively transport both cations (e.g., H+) and anions (e.g., OH–) simultaneously, enabling hydrogen production in acids and oxygen evolution in alkalis. The unique properties of BPMs enable promising applications in water electrolysis (WE) and have, therefore, attracted a lack of research attention in recent years. In this review, critical challenges for their potential applications in WE systems are highlighted, including chemical/mechanical stability, ionic conductivity, ion exchange capacity, water dissociation, transport efficiency, etc. Drawing upon recent research findings, a number of promising strategies have been identified for enhancing the performance of BPMWE systems. These include the optimization of AEL and CEL polymer chemistry, the construction of asymmetric membrane structures, the incorporation of water dissociation (WD) catalysts, and the design of 2D/3D structures at the bipolar junction as well as advanced fabrication techniques. In summary, this review offers valuable insights for advancing the development and practical implementation of BPM technology in WE systems and other energy-related domains.