Materials and flow fields of bipolar plates in polymer electrolyte membrane water electrolysis: A review

Hydrogen serves as an efficient energy vector with advantages such as high energy density, greenness, and cleanliness. Hydrogen generation from water electrolysis with renewable energy is an effective approach for achieving renewable energy consumption and green hydrogen energy production. Polymer electrolyte membrane water electrolysis (PEMWE) is capable of presenting the merits of high current density, high productivity, superior gas purity, low energy consumption and high safety. The development of PEMWE is an important part of achieving the coupling of renewable energy, electric energy and hydrogen energy. As a crucial component of PEMWE, bipolar plates (BPs) constitute the mechanical support of the whole cell and provide a channel for electron transport and material supply. These channels determine the electrochemical and hydrodynamic response of a PEMWE. This work reviews the latest developments and applications of BPs, with a focus on the challenges of flow field structure and material fabrication. The specific content covers the BP matrix, types of surface layers, and effect of flow field design on mass transfer. Extended-term growth and feasibility studies of BPs, which can provide a reference and guidance for the configuration of high-behavior flow fields in PEMWEs in the long run, are envisioned.