MnOx anchored on N and O co-doped carbon nanotubes encapsulated with FeCo alloy as highly efficient bifunctional electrocatalyst for rechargeable Zinc–Air batteries

Abstract Currently, development of OER/ORR bifunctional electric catalysts with low cost, high catalytic activity and stability is the key step to promote the practical application of zinc-air batteries. Herein, composite catalyst with manganese oxide on N and O co-doped carbon nanotubes encapsulated with FeCo alloy (CoFe@CNT/MnO) was prepared in situ on CFP by hydrothermal and CVD pyrolysis methods. Owing to rich C O functional group on in situ growing carbon nanotubes with 3D open structure, alloying effect of CoFe core metal embedded in carbon nanotube and the contribution of MnO supported on carbon nanotubes to ORR performance and stability, the CoFe@CNT/MnO catalyst exhibits low overpotential of 193 mV at the current density of 10 mA/cm2 for OER, larger diffusion-limited current density of 5.75 mA/cm2 and half-wave potential (E1/2 = 0.85 V) for ORR, high specific capacity (810 mAh/gZn) and peak power density (164 mW/cm2) with the Zn-air battery and superior stability. Moreover, the peak power density of the single CoFe@CNT/MnO-based quasi-solid state ZAB could reach 142 mW/cm2, and two quasi-solid state ZABs connected in series can power a mini fan.