Metal‐organic framework‐derived Fe/Cu‐substituted Co nanoparticles embedded in CNTs‐grafted carbon polyhedron for Zn‐air batteries

Abstract

AbstractMetal‐organic frameworks (MOFs) and MOF‐derived materials have attracted great attention as alternatives to noble‐metal based electrocatalysts owing to their intriguing structure properties, especially for high efficiency and stable oxygen reduction reaction (ORR). Herein, we employed a one‐pot reaction to make a multimetal (Fe, Co, Cu, and Zn) mixed zeolitic imidazolate framework (MM‐ZIF) via adopting a simple in situ redox reaction. Further pyrolysis of the target MM‐ZIF, a highly porous carbon polyhedron (FC‐C@NC) grafted with abundant carbon nanotubes was obtained, in which ultrasmall Co nanoparticles with partial lattice sites substituted by Fe and Cu were embedded. The obtained FC‐C@NC possessed large surface area, highly porous structure, widely‐spread metal active sites, and conductive carbon frameworks, contributing to outstanding ORR activity and long‐term stability. It displayed superior tolerance to methanol crossover and exceeded the commercial Pt/C catalyst and most previously reported non‐noble‐metal catalysts. Impressively, the as‐produced FC‐C@NC‐based zinc‐air battery afforded an open‐circuit potential of 1.466 V, a large specific capacity of 659.5 mAh/g, and a high gravimetric energy density of 784.3 Wh/kgZn, significantly outperforming the Pt/C‐based cathode.