Nano bowl-like cobalt-cobalt molybdenum carbide coated by N,P co-doped carbon as an advanced bifunctional oxygen electrocatalyst for rechargeable Zn-air batteries.

Abstract

Nano bowl-like Co-Co6Mo6C2 coated by N,P co-doped carbon (Co-Co6Mo6C2@NPC) is reported as an electrocatalyst for Zn-air batteries. Co-Co6Mo6C2@NPC only needs an overpotential of 210 mV at 10 mA cm-2 for the OER, and the half-wave potential for the ORR is 0.81 V. In addition, the Co-Co6Mo6C2@NPC based battery shows a large open-circuit voltage of 1.335 V and a maximum power density of 160.5 mW cm-2, as well as good stability. The improved catalytic performance can be ascribed to the co-existence of Co6Mo6C2 and Co species to improve the intrinsic catalytic activity, and the bowl-like nanostructure to facilitate the mass transfer.