CeO2-Decorated Co@NCNT Heterostructures as an Advanced Air Electrode for High-Performance Zinc-Air Batteries

Abstract Nitrogen-doped carbon nanotube (NCNT)-supported cobalt-based catalysts are recognized as promising and viable alternatives to platinum-group metals for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, the electrocatalytic performance of monometallic Co@NCNT catalysts is still insufficient to meet the rigorous demands of practical applications. In this work, CeCo-ZIF was first synthesized using a facile one-step hydrothermal process. Subsequently, dicyandiamide (DCD) was introduced as the nitrogen source, and the Co@NCNT/CeO2 composite catalyst was successfully fabricated via a sintering process. The synergistic effect among Co, NCNTs, and CeO2 effectively overcomes the inherent drawbacks of single Co@NCNT catalysts. Benefiting from the outstanding oxygen storage/release capability of CeO2, the Co@NCNT/CeO2 composite optimizes the electronic structure of Co active sites. When employed as the cathode catalyst for zinc-air batteries, it delivers a higher open-circuit voltage of 1.48 V, a superior specific capacity (806.63 mAh·g–1) compared with commercial catalysts, and outstanding cycling stability exceeding 250 h, demonstrating broad application prospects in high-performance zinc-air batteries.