Fabricating highly active and stable tungsten carbide electrocatalyst for rechargeable zinc–air batteries: An approach of dual metal Co-adjusted the electronic structure

Abstract The slow kinetics of oxygen reduction reaction (ORR) severely effects the operation of the zinc-air battery. A suitable electrocatalyst (represented by platinum-based catalyst) is required to catalyze this reaction process. However, the limitation of poor stability and high cost from platinum-based materials have seriously hindered the commercial development of zinc-air batteries. Considering the importance of stability, tungsten carbide (WC) is an extremely attractive candidate material because of its high electrical conductivity and corrosion resistance. Herein, Fe, Co co-doped tungsten carbide/nitrogen-doped carbon catalyst (FeCo-WC/NC) was synthesized by hydrothermal assisted vacuum rapid calcination. The Fe and Co with d-orbital multi-electron transition metals can adjust the electronic structure of WC, reduce the energy barrier of oxygen reduction reaction, and improve the catalytic efficiency. FeCo-WC/NC exhibited a high limiting current density of 5.62 mA cm−2, a positive half-wave potential of 0.85 V and excellent stability. Zinc-air batteries successfully assembled by FeCo-WC/NC showed a power density of 122.52 mW cm−2, a specific capacity of 744 mAh g−1 and outstanding cyclical stability. This work may offer a facile fabrication of WC catalysts with the enhanced performance in the ORR and zinc-air battery.