Soft‐Pyrolysis Co–N‐Implanted Polymer to Gain High‐Density Co–Nx Sites on Carbons for Efficient Oxygen Reduction in Zn–Air Batteries

Abstract

A soft‐pyrolysis strategy by heating Co–N‐implanted covalent organic polymer combining on carbon nanotubes at ≤500 °C has been developed to obtain efficient Co–N–C electrocatalysts for oxygen reduction reaction (ORR). The prepared Co–N–C is highly active for ORR with a half‐wave potential of 0.91 V versus RHE in 0.1 m KOH electrolyte, superior to most of previously reported Co‐based electrocatalysts. When employing it as cathode electrocatalyst, the homemade Zn–air battery shows a peak power density of 304.2 mW cm−2, comparable to the parallel power density (250 mW cm−2) of Zn–air battery with Pt/C (20 wt%) electrocatalyst at cathode. The soft‐pyrolysis strategy not only helps to generate high density Co–Nx active sites on carbons but also facilitates the optimizing balance between active site densities, graphitization degree, and pore structure of Co–N–C catalysts. Herein, a simple and energy‐effective low‐temperature pyrolysis strategy to obtain high‐performance ORR electrocatalyst is provided.