Scalable production of high-performance electrocatalysts for electrochemical water splitting at large current densities

Electrochemical water splitting is a pivotal technology in the large-scale production of green hydrogen for sustainable future energy provisions. Highly active, stable electrocatalysts have been extensively explored, but the majority suffer from low current densities and small sizes, rendering them unsuitable for industrial applications. Recently, however, the scalable production of electrocatalysts with high performance at large current densities has made tremendous progress. In this review, the current achievements in developing outstanding large electrocatalysts for high-current-density water electrolysis are described in detail. First, we introduce the fundamentals of water electrolysis, the criteria for performance evaluation, and the requirements for producing electrocatalysts at scale under large current densities. Second, we summarize the key approaches for realizing large-sized electrocatalysts with excellent performance, including electrodeposition, corrosion engineering, and thermal treatment, as well as combinations of these methods. Finally, we offer perspectives on research challenges and propose directions for mass-producing high-performance electrocatalysts with large current densities for water electrolysis, to guide the further industrialization of water-electrolysis catalysts. • The fundamentals and evaluation criteria of large-current-density water electrolysis are described. • The key requirements for the scalable production of large-current-density electrocatalysts are laid out. • Synthetic approaches for developing large-sized electrocatalysts with large current densities are summarized in detail. • Challenges and directions are proposed for realizing large-sized catalysts toward large-current-density water electrolysis.