Stable nickel-iron-phosphorus coating on nickel mesh for oxygen

Abstract

The widespread commercialization of water electrolysis for H₂ production is limited by the lack of high-performance, low-cost electrodes. Nickel-iron phosphide (NiFeP) is a promising oxygen evolution reaction (OER) electrocatalyst in alkaline media, but its practical use is hindered by insufficient activity at high current densities, poor long-term stability, and difficulty achieving uniform, robust loading on porous nickel mesh (NM), critical for industrial-scale fabrication. Herein, we report a electroless plating technique using tin (Sn) as a promoter under low-temperature conditions, which enables the in situ growth of amorphous nickel-iron-phosphorus on a smooth NM surface (NiFeP-Sn/NM). SnO₂, as the inner core, provides deposition sites for Ni/Fe on smooth NM, slowing Ni²⁺ oxidation, inhibiting active component leaching, and promoting collapse-resistant NiFeP agglomerates to balance activity and stability. As expected, NiFeP-Sn/NM exhibits excellent industrial OER performance. Compared with NiFeP/NM (332 mV) and Ni/NM (460 mV), NiFeP-Sn/NM can drive a current density of 100 mA cm^-2 with only 309 mV of overpotential. Importantly, stable operation under typical industrial conditions (500 mA cm^-2) is achieved during prolonged electrolyzer testing (the cell voltage is maintained at around 1.9 V), with no observable overpotential decay. This low-cost, scalable method solves NiFeP loading issues on NM, offering a feasible route for industrial production of high-performance OER electrodes and advancing water electrolysis commercialization.