Mn-doped Co nanoparticles on wood-derived monolithic carbon for rechargeable zinc–air batteries

Abstract

The large-scale applications of zinc–air batteries (ZABs) as vital energy storage devices have been limited by the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the air electrode. Herein, Mn-doped Co nanoparticles on cedarwood-derived carbon (CoMn-N@NCW) are fabricated as a bifunctional catalyst to boost the reaction kinetics. The as-prepared catalyst shows a half-wave potential of 0.885 V for the ORR and an overpotential of 335 mV at 10 mA cm⁻² for the OER in alkaline electrolytes. ZABs based on the catalyst exhibit a high peak power density of 186 mW cm⁻² and a robust lifetime of 600 h. The quasi-solid-state ZABs assembled with CoMn-N@NCW exhibit a splendid open-circuit voltage of 1.493 V and a long-term cycling stability of 70 h. Oxygen electrocatalytic kinetics are improved by the electronic modulation of cobalt from adjacent manganese and the rapid mass transfer of porous biomass carbon. This work provides a remarkable inspiration to prepare a practically applicable oxygen electrode for ZABs.