Self-template synthesized ZIF-derived polyhedron-connected porous Co-N-C as oxygen reduction catalyst for Zn-Air batteries

Abstract

The strategic development of high-efficiency electrocatalysts for the oxygen reduction reaction (ORR) remains a pivotal challenge in advancing high-performance zinc-air batteries (ZABs) towards commercial viability. In this work, we developed a template-directed synthesis of Co, N-co-doped polyhedral carbon 3D frameworks (Co-N-C-x) through controlled pyrolysis of Co-ZIF precursors grown on Co-ZnO nanorod self-template. Owing to its unique carbon skeleton architecture and uniform dispersion of Co and N species, the optimized catalyst (Co-N-C-7%) exhibits enhanced ion/electron-transfer kinetics, improved mass transport capabilities. Consequently, the Co-N-C-7% catalyst exhibits superior ORR performance, achieving a half-wave potential (E1/2 = 0.878 V vs. RHE) that is 3 mV higher than commercial 20 wt% Pt/C (E1/2 = 0.875 V vs. RHE), along with exceptional stability. When applied in ZABs, the Co-N-C-7% cathode delivers a higher peak power density (178 mW cm-2) compared to Pt/C-based counterparts (152 mW cm-2). This work provides a simple and reliable control scheme for designing cost-effective, high-performance, and durable ORR electrocatalysts.