A stable alkaline anion exchange membrane water electrolyzer based on a self-healing anode

Designing high-efficiency, stable, and low-cost noble-metal-free water-splitting devices for hydrogen production and understanding their catalytic mechanism are of great significance to solving the energy crisis. Herein, borate-intercalated nickel cobalt iron oxyhydroxide (NiCoFe–Bi) deposited on nickel foam (NF) anode is successfully synthesized via one-step electrodeposition. In the half-cell test, the NiCoFe–Bi/NF anode exhibits an overpotential of 340 mV for OER at the current density of 500 mA cm−2 with a Tafel slope of 30.0 mV/dec at 50 °C. Owing to the unique self-healing mechanism of Fe active centers during the electrolysis process, when coupled with a Co3S4 nanosheet/NF cathode, the resulting anion exchange membrane water electrolyzer (AEMWE) achieved stable hydrogen production for over 100 h with an operating current density of 500 mA/cm2 and a cell voltage of 1.98 V at 50 °C. These results demonstrate the high durability and efficiency of the self-healing catalyst under operational conditions, paving a pathway for industrial applications of AEMWE for hydrogen production.