Heterointerface-Enabled Anti-Reverse-Current Electrodes for Alkaline Water Electrolyzers at 1000 mA cm^-2

Achieving stable and efficient alkaline water electrolysis (AWE) under fluctuating renewable energy inputs is essential for large-scale green hydrogen production. However, frequent shutdown-induced reverse current (RC) effects pose significant challenges to electrode durability. Here, we introduce a gradient interlayer engineering strategy to develop robust AWE electrodes that intrinsically resist both electrochemical reconstruction and mechanical fatigue. By constructing a dense interlayer with Ni(112̅)/Ni₃S₂(1̅20) heterointerfaces, the electrode demonstrates high catalytic activity (1.79 V @1000 mA cm^-2─meeting the U.S. DOE 2026 target), excellent operational stability (>1500 h at 1000 mA cm^-2 in 30 wt % KOH at 80 °C), and exceptional RC resistance for 3600 accelerated startup/shutdown cycles. Mechanistic studies through cross-sectional characterizations and theoretical calculations reveal that the seamless interlayer at the catalyst-substrate interface enhances interfacial adhesion, mitigates lattice mismatch, and facilitates charge redistribution, ensuring robust stability and integrity even under operational strains and potential reversals. This work establishes interface crystallography as a design paradigm for durable electrodes, potentially overcoming the stability-activity dilemma toward industrially relevant electrolyzers coupled with fluctuating renewable energy sources.