Unlocking the Potential of Tailored Hollow Carbon Spheres for High-Performance Zinc-Air Batteries

Abstract

A low-cost, highly stable, bifunctional electrocatalyst is crucial for advancing zinc-air battery technology. This study introduces a cobalt oxide-decorated nitrogen sulfur dual-doped hollow carbon sphere, as a promising candidate for the air cathode of a zinc-air battery. Synthesized using a novel single-step hard template method, the catalyst exhibits exceptional performance in both oxygen evolution and oxygen reduction reactions, rivaling commercial RuO₂ and Pt/C catalysts. This enhanced bifunctional activity is due to the synergistic effects of metal oxide decoration and heteroatom doping (nitrogen, sulfur). When integrated into a zinc-air battery, the catalyst delivers an impressive power density (205 mW cm^–2) and specific capacitance (737 mA h g^–1), surpassing commercial alternatives. The catalyst demonstrates exceptional long-term stability, maintaining its performance for over 160 h, a significant improvement compared with commercial Pt/C + RuO₂. These results highlight the outstanding stability and durability of cobalt oxide-decorated nitrogen sulfur dual-doped hollow carbon sphere as a promising candidate for air cathode materials in future zinc-air batteries.