Cobalt loaded on concave hollow carbon octadecahedron for zinc–air batteries

Abstract

For the development of high-performance zinc–air batteries, it is necessary to increase the kinetics of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) as much as possible. In this work, different coordination structures of Co loaded on concave hollow carbon octadecahedron (CNQD/CoNBs) were prepared by adding g-C3N4 into the synthesis process of Co-based zeolitic imidazolate framework and adjusting the stress balance of the framework structure in the pyrolysis process. This method can greatly increase the specific surface area and the number of micropores of the material for exposing more active sites to accelerate the reaction kinetics. The prepared catalyst shows excellent bi-functional performance for OER and ORR, and it is applied in efficient rechargeable zinc–air battery to achieve high discharge power density of 210 mW/cm2 and favorable stability over long charge/discharge cycles. This research provides an effective strategy to design high-efficiency bi-functional electrocatalysts.