Abstract: Hydrogen energy, whether in generation plants or utilization facilities, plays a decisive role in the mission to achieve net-zero greenhouse gas emissions, all to minimize pollution. The growing demand for clean energy carrier steadily accelerates the development of hydrogen production processes, and therein proton exchange membrane (PEM) water electrolysis is deemed a promising long-term strategy for hydrogen preparation and collection. This review retrospects recent developments and applications of bipolar plates (BPs) as key components in PEM fuel cells and water electrolysers. The main content includes multifaceted challenges in the R&D or fabrication of BPs and potential future trends have also been proposed. Specific details cover the BPs matrix (metallic materials and carbon composites) and the surface coating types (metal and compound coatings, carbon-based coatings, and polymer coatings), as well as the influence of flow field design for mass transport. Long-term development and feasible researches of BPs are prospected. Especially in the following aspects: (1) Structural and functional integration of components, such as material fabrication and flow field geometry optimization using 3D printing technology; (2) Introduction of environment-friendly renewable energy for hydrogen production; (3) Research on hydrogen energy reversible systems; (4) Composition optimization of surface coatings based on computational materials science and (5) systematic design expected to evolve into the next generation of BPs.

Key words: PEM water electrolyser, Bipolar plates, Corrosion, Coatings, Interfacial contact resistance