Metal coordination enhanced Ni–Co@N-doped porous carbon core–shell microsphere bi-functional electrocatalyst and its application in rechargeable zinc/air batteries

Abstract

Primary and rechargeable zinc/air batteries could be the next generation of energy storage devices because of their high power density and safety. The activity and durability of the catalyst play an important role in enhancing the electrochemical performance of the battery. Herein, Ni–Co@N-doped porous carbon (NC@NPC) core–shell microspheres are proposed as a bifunctional catalyst which exhibits significantly enhanced onset oxygen reduction reaction (ORR) potential (−0.19 V vs. Ag/AgCl) and oxygen evolution reaction (OER) current density (16.2 mA cm⁻² at 0.8 V vs. Ag/AgCl) due to the synergy of metallic Ni and Co. Namely, practical rechargeable NC@NPC loaded zinc/air battery testing using oxygen in air demonstrates desirable discharge voltages at current densities up to 80 mA cm⁻². Besides, steady charge and discharge voltages at the current density of 10 mA cm⁻² are obtained over 60 cycles.