Roll-to-Roll Production of Electrocatalysts Achieving High-Current Alkaline Water Splitting

Scalable production of electrocatalysts capable of performing high-current water splitting is crucial to support green energy utilization. We adopted acidic redox-assisted deposition (ARD) to realize the continuous roll-to-roll fabrication of a strongly adherent cobalt manganese oxyhydroxide (CMOH) film on Ni foam under ambient conditions in water. The as-fabricated products show uniform CMOH coverage and oxygen evolution activities with dimensions as large as 5 m length by 0.25 m width. Also, we converted CMOH into a metallic form (denoted as CM) with the preserved high adhesion to serve as a high-current hydrogen evolution electrocatalyst. Our results reveal that the insufficient adhesion of powder forms electrocatalysts (i.e., Pt and RuO2 as benchmarks), even with the binder, at high-current electrolysis (>1000 mA) can be solved using the fabricated CM||CMOH cell. With an active area of 1 cm × 1 cm assembly in anion exchange membrane (AEM) electrolyzers, we observed the remarkable record of alkaline electrolysis stably at 5000 mA. This result established a new benchmark record on the high-current water splitting research.