Intermittent polarity inversion of stainless-steel paired electrodes for efficient and durable water electrolysis

Designing robust and cost-effective catalysts through straightforward and replicable techniques is crucial for advancing water electrolysis. In this study, we introduce a dynamic polarization control method for the continuous activation of stainless steel (SS) substrates to achieve high water-splitting performance and durability. By applying periodic inverted current density during high-current-density operation (0.5 or 1 A cm(-2)) on bare SS adopted as both cathode and anode substrates, a NiFe-based oxide structure favorable for the hydrogen evolution reaction is formed at the cathode, while a Fe-incorporated NiOOH structure with high efficacy for the oxygen evolution reaction develops at the anode. Implemented in an anion exchange membrane water electrolysis system, this inverted polarization approach applied for the SS paired electrolyzer system successfully maintains a cell voltage of approximately 1.9 V for 500 h at a current density of 1 A cm(-2) using bare SS for both electrodes.