Fluctuation-tolerant non-precious bifunctional Ni–Co–B monolithic electrodes for industrial-scale anion exchange membrane water electrolysis

Abstract

To address the stability challenges faced during anion exchange membrane water electrolysis (AEM-WE) using intermittent renewable energy, a fluctuation-tolerant bifunctional nickel–cobalt–boron (a-NiCoB) monolithic electrode was successfully developed in this study. The unique homogeneous monolithic design of the electrode eliminates the traditional fragile substrate–catalyst heterogeneous interfaces, leading to remarkable stability against the vigorous bubble impact at high current densities over 4 A cm⁻². Meanwhile, the synergy between Co-doping and in situ surface reconstruction facilitates precise electronic structure modulation, effectively suppressing active Ni dissolution. Consequently, the a-NiCoB electrode exhibits superior catalytic activity and robust stability under fluctuating conditions in a 1 M KOH electrolyte, delivering ultralow overpotentials at 100 mA cm⁻² (HER (hydrogen evolution reaction): 72 mV; OER (oxygen evolution reaction): 254 mV) and its HER/OER performance remains undegraded after 350 h and 10 500 intensive start–stop cycles at 1 A cm⁻². The AEM electrolyzer, with a-NiCoB as both the anode and the cathode, requires only 1.82 V to reach 1000 mA cm⁻² in 1 M KOH at 60 °C. Encouragingly, it can also sustain a vigorous fluctuating load between 50 and 2000 mA cm⁻² over 1440 cycles and the accelerated startup/shutdown cycle with negligible decay. This work synergistically optimizes activity and durability through structural design and compositional regulation, offering a highly promising technological pathway for the scalable development of green hydrogen energy.