Soft‐pyrolysis Co‐N‐implanted polymer to gain high density Co‐Nx sites on carbons for efficient oxygen reduction in Zn‐air batteries

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–N x 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.