Author: Xiaohong Zou (The Hong Kong Polytechnic University) - Rechargeable zinc-air batteries have emerged as the promising next-generation energy storage technology due to their exceptional theoretical energy density , enhanced safety profile, cost-effectiveness, and environmental compatibility compared to conventional battery systems. Nevertheless, the practical implementation of zinc-air batteries faces significant challenges arising from sluggish oxygen redox kinetics at the air cathode, particularly during the oxygen evolution reaction processes. This kinetic limitation manifests as elevated charge overpotentials and reduced cycle stability, substantially compromising overall battery performance. Consequently, substantial research efforts are directed toward developing alternative electrocatalysts that simultaneously satisfy three critical requirements: (1) cost-effective synthesis from earth-abundant elements, (2) superior catalytic activity for oxygen evolution reaction, and (3) robust structural durability throughout extended charge-discharge cycling. Significant research has focused on developing transition metal-based oxygen evolution reaction electrocatalysts, such as oxides, layered double hydroxides, nitrides, and sulfides, to mitigate high charge potentials in Zn-air batteries. Herein, we synthesized ultrasmall Ni3Fe oxide nanoparticles anchored on polyaniline via solvothermal synthesis and calcination. The Ni3Fe- polyaniline interfacial interaction, mediated by Ni-N bonds, strengthens Ni-O covalency, thereby optimizing charge redistribution. Additionally, polyaniline conductive framework facilitates synergistic electron transfer, ion diffusion, and gas release, collectively enhancing oxygen evolution reaction kinetics and sustained stability for Zn-air batteries. This work elucidates the critical role of catalyst-support electronic coupling in amplifying oxygen evolution reaction activity, providing a design blueprint for advanced electrocatalysts for rechargeable Zn-air batteries.
