Plasma Induced Atomic‐Scale Soldering Enhanced Efficiency and Stability of Electrocatalysts for Ampere‐Level Current Density Water Splitting

Abstract Industrial water electrolysis typically operates at high current densities, the efficiency and stability of catalysts are greatly influenced by mass transport processes and adhesion with substrates. The core scientific issues revolve around reducing transport overpotential losses and enhancing catalyst‐substrate binding to ensure long‐term performance. Herein, vertical Ni‐Co‐P is synthesized and employed plasma treatment for dual modification of its surface and interface with the substrate. The (N)Ni‐Co‐P/Ni₃N cathode exhibits an ultra‐low overpotential of 421 mV at 4000 mA cm⁻², and the non‐noble metal system only requires a voltage of 1.85 V to reach 1000 mA cm⁻². When integrated into an anion exchange membrane (AEM) electrolyzer, it can operate stably for >300 h at 500 mA cm⁻². Under natural light, the solar‐driven AEM electrolyzer operates at a current density up to 1585 mA cm⁻² with a solar‐to‐hydrogen efficiency (SHT) of 9.08%. Density functional theory (DFT) calculations reveal that plasma modification leads to an “atomic‐scale soldering” effect, where the Ni₃N strong coupling with the Co increases free charge density, simultaneously enhancing stability and conductivity. This research offers a promising avenue for optimizing ampere‐level current density water splitting, paving the way for efficient and sustainable industrial hydrogen production.