FeCo alloy modified MoN electrocatalyst with excellent ORR and OER activities for Zn-air battery

Abstract

Regarded as a burgeoning energy conversion and storage device, Zn-air battery achieves charge/discharge through oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). However, the sluggish kinetics of ORR and OER affects charge/discharge performance of Zn-air battery significantly. MoN-based electrocatalysts exhibit ORR and OER activities. However, it is necessary to further improve their performance when they are used in Zn-air battery. Herein, bifunctional electrocatalyst, namely FeCo/MoN@NCNTs (NCNTs = N-doped carbon nanotubes), is synthesized, with FeCo and MoN particles evenly distributed in NCNTs. It shows typical four-electron character in ORR with perfect activity. In OER, it exhibits low overpotential and Tafel slope. In both ORR and OER, FeCo/MoN@NCNTs demonstrates high stability. When taken as electrocatalyst in Zn-air battery, it achieves a peak power density of 100.4 mW cm⁻². At 1 mA cm⁻², the specific capacitance and energy density reach 860.2 mAh g⁻¹ and 1101.1 Wh kg⁻¹. This Zn-air battery also exhibits high rating capacity and stability. By developing an excellent bifunctional electrocatalyst for Zn-air battery, this study contributes a feasible solution to enhancing the ORR and OER activities of MoN-based electrocatalyst.