Accelerating OH^- Transport for 5000-Hour-Stable Kilowatt-Scale Alkaline Water Electrolysis.

Abstract

Enhancing the continuous supply of OH^- reactants to anode catalytic sites under high current density is critical for the development of alkaline water electrolyzer (AWE). Herein, a strategy for promoting OH^- transport is demonstrated by using rare earth oxide clusters (REO_x) to reconfigure interfacial hydrogen bond networks. This structural modulation achieves a nearly threefold increase in the OH^- transport rate. Mechanistic analysis reveals that the incorporation of rare earth weakens the charge-dipole interaction between the oxygen in the ^*OH intermediate and interfacial H₂O molecules, promoting the transition from a rigid, ordered interfacial water structure to a more isolated, loose configuration. A linear correlation among the proportions of isolated water species, OH^- transport rates, and OER activity across a series of REO_x/NiCo₂S₄ catalysts supports this mechanism. A kilowatt-scale AWE consisting of 17 cells with a total active area of 1334 cm² was assembled using a DyO_x/NiCo₂S₄ anode. For the first time, the system operated stably for over 5,000 h at a current of 39.25 A under industrial operating conditions, achieving a cumulative hydrogen output of 1,400 Nm³. This work highlights the potential of manipulating the electrode-electrolyte interface to enhance catalyst performance in producing industrial-scale green hydrogen.