Developing Practical Catalysts for High-Current-Density Water Electrolysis

High-current-density water electrolysis is considered a promising technology for industrial-scale green hydrogen production, which is of significant value to energy decarbonization and numerous sustainable industrial applications. To date, substantial research advancements are achieved in catalyst design for laboratory-based water electrolysis. While the designed catalysts demonstrate remarkable performance at laboratory-based low current densities, they suffer from marked deteriorations in both activity and long-term stability under industrial-level high-current-density operations. To provide a timely assessment that helps bridge the gap between laboratory-scale fundamental research and industrial-scale practical water electrolysis technology, here the current advancements in various commercial water electrolyzers are first systematically analyzed, then the key parameters including work temperature, current density, lifetime of stacks, cell efficiency, and capital cost of stacks are critically evaluated. In addition, the impact of high current density on the electrocatalytic behavior of catalysts, including intrinsic activity, long-term stability, and mass transfer, is discussed to advance the catalyst design. Therefore, by covering a range of critical issues from fundamental material design principles to industrial-scale performance parameters, here the future research directions in the development of highly efficient and low-cost catalysts are presented and a procedure for screening laboratory-designed catalysts for industrial-scale water electrolysis is outlined.