Co-embedded carbon nanotubes modified N-doped carbon derived from poly(Schiff base) and zeolitic imidazole frameworks as efficient oxygen electrocatalyst towards rechargeable Zn-air battery

Abstract

Developing nonprecious-metal bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is greatly significant for rechargeable metal-air batteries. In this work, Co nanoparticles encapsulated in nitrogen-doped carbon nanotubes (CNTs) tangled with nitrogen-doped carbon (Co@CNT-NC) has been obtained via a facile in-situ growth-pyrolysis route with the hybrid of zeolitic-imidazole-framework-67 nanoparticles and a triazine-containing poly(Schiff-base). Benefiting from its high surface area (1458 m2 g−1), effective N dopant, interwoven with CNTs and the synergistic effects of Co nanoparticles and nitrogen-doped carbon matrix, the optimized Co@CNT-NC exhibits a superior bifunctional activity with a small potential difference (0.76 V) between OER and ORR. The assembled Co@CNT-NC-based zinc-air battery displays a high power density of 179.3 mW cm−2, a high energy density up to 949 mAh gZn−1 and outstanding long-term durability.