Strong interaction and confine effect of manganese oxide-cobalt embedded in self-templated nitrogen-doped carbon enable ultra-stable zinc-air batteries

Abstract

Developing efficient bifunctional oxygen electrocatalysts with high stability is of great significance for the implementation of rechargeable Zn–air batteries. Herein, MOC-NC bifunctional electrocatalyst with active MnO–Co components embedded in the N-doped carbon sphere is prepared by facile hydrothermal conversion and post-pyrolysis process. The strong interaction between MnO and Co, and confine effect induced by the microstructure endow the fabricated MOC-NC composite with modified electronic configuration, improved conductivity, and significantly reinforced stability. Consequently, the MOC-NC electrocatalyst exhibits good activity and ultrahigh stability for oxygen electrocatalysis. Moreover, when the catalyst was applied to the cathode electrode for the zinc-air battery, it shows excellent performance (specific capacity of 718 ​Wh kgZn−1, power density of 152.3 ​mW ​cm−2) and extraordinary long-term stability (after 200 ​h of charge and discharge cycling, the round-trip efficiency still maintains at 44%). The present work demonstrates a strategy for synthesizing ultrastable bifunctional non-precious metal electrocatalysts for oxygen electrocatalysis.