Poly-active centric Co3O4-CeO2/Co-N-C composites as superior oxygen reduction catalysts for Zn-air batteries

Abstract

Zinc-air battery is one of the most promising next-generation energy conversion and storage systems. Green and low-cost catalysts with high oxygen reduction reaction (ORR) catalytic activity are desired to meet the requirements of Zinc-air batteries. Herein, poly-active centric Co3O4-CeO2/Co-N-C (ketjenblack carbon) catalysts were prepared by a facile method. The Co3O4 and CeO2 nanoparticles are uniformly anchored on the surface of Co and N doped carbon support. The half-wave potential of Co3O4-CeO2/Co-N-C in the rotating disk electrode testing is close to that of Pt/C. The Zn-air battery using Co3O4-CeO2/Co-N-C as the cathode catalyst can provide a high specific capacity of 728 mA h g−1 at 20 mA cm−2 and maintain a stable discharge voltage. The remarkable catalytic performance is mainly attributed to the synergistic effect among Co3O4, CeO2 and Co-N-C, the outstanding electrical conductivity and the large surface area. Benefitting from the high catalytic activity, environmental friendliness and the facile synthesis process, Co3O4-CeO2/Co-N-C catalyst lends itself well to a great prospect in the application of metal-air batteries.