Ni-doped Mn2O3 microspheres as highly efficient electrocatalyst for oxygen reduction reaction and Zn-air battery

Herein, Ni-doped Mn2O3 microspheres are successfully synthesized via the facile coprecipitation of metal ions and ammonium bicarbonates, followed by a heat treatment process. Ni-doped Mn2O3 exhibits outstanding catalytic performance toward the oxygen reduction reaction (ORR) in alkaline media with a half-wave potential of 0.801 V, limiting current density of 6.02 mA cm−2 at 0.6 V vs. RHE, outstanding long-term durability, and strong tolerance to methanol. Furthermore, a Zn–air primary battery using Ni-doped Mn2O3 as an air cathode shows high open-circuit voltage of 1.52 V and high power density of 88.2 mW cm−2, outperforming the commercial Pt/C cathode. The exceptional performance of the Ni-doped Mn2O3 microspheres is ascribed to the hierarchical structure, optimized particle size, and Ni incorporation into Mn2O3. The proposed synthesis strategy provides a new methodology for the design and fabrication of electrochemically active transition metal-doped materials as efficient electrocatalysts for a variety of energy storage and conversion reactions.