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 by 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 vigorous bubble impact at high current density 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 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 10500 intensive start-stop cycles at 1 A cm−2. AEM electrolyzer with a-NiCoB as both anode and cathode, requires only 1.82 V to reach 1000 mA cm−2 in 1 M KOH at 60 oC. Encouragingly, it can also sustain vigorous fluctuating load between 50-2000 mA cm−2 over 1,440 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.