Alloying Co Species into Ordered and Interconnected Macroporous Carbon Polyhedra for Efficient Oxygen Reduction Reaction in Rechargeable Zinc–Air Batteries

Abstract

Abstract Engineering non‐precious transition metal (TM)‐based electrocatalysts to simultaneously achieve an optimal intrinsic activity, high density of active sites, and rapid mass transfer ability for the oxygen reduction reaction (ORR) remains a significant challenge. To address this challenge, a hybrid composite consisting of Fe x Co alloy nanoparticles uniformly implanted into hierarchically ordered macro‐/meso‐/microporous N‐doped carbon polyhedra (HOMNCP) is rationally designed. The combined results of experimental and theoretical investigations indicate that the alloying of Co enables a favorable electronic structure for the formation of the *OH intermediate, while the periodically trimodal‐porous structured carbon matrix structure not only provides highly accessible channels for active site utilization but also dramatically facilitates mass transfer in the catalytic process. As expected, the Fe 0.5 Co@HOMNCP composite catalyst exhibits extraordinary ORR activity with a half‐wave potential of 0.903 V (vs reversible hydrogen electrode), surpassing most Co‐based catalysts reported to date. More remarkably, the use of the Fe 0.5 Co@HOMNCP catalyst as the air electrode in a zinc–air battery results in superior open‐circuit voltage and power density compared to a commercial Pt/C + IrO 2 catalyst. The results of this study are expected to inspire the development of advanced TM‐based catalysts for energy storage and conversion applications.