Rechargeable zinc-air batteries, which are cost-effective, environmental compatibility, and have high energy density, are promising energy storage devices for renewable energy and power sources for electric transportation. However, the critical issues that impede the commercialization of rechargeable zinc–air batteries are limited charge and discharge cycles and the sluggish kinetics of oxygen reduction and evolution reactions, which affect the round trip efficiency. Over the past years, numerous efforts have been devoted to develop earth-abundant materials as bifunctional catalysts towards both OER and ORR. But a suitable bifunctional catalyst has not really been found yet. Therefore, the rechargeable zinc–air battery with cobalt oxide nanoparticles as a bifunctional catalyst are investigated. The result shows that the rechargeable zinc-air batteries in a two-electrode configuration exhibited a small charge–discharge voltage polarization of ~0.70 V at 5 mA cm⁻², high reversibility and stability during battery discharge, charge, and cycling processes.