Novel cobalt-doped molybdenum oxynitride quantum dot@N-doped carbon nanosheets with abundant oxygen vacancies for long-life rechargeable zinc-air batteries†

Rechargeable zinc-air batteries (ZABs) have emerged as promising alternatives for conventional Li-ion batteries due to their high energy density and low manufacturing cost. However, Pt/C and RuO2-based conventional rechargeable ZABs are mainly constrained by the sluggish kinetics of oxygen reduction/oxygen evolution reactions (ORR/OER), limiting commercialization possibilities. Herein, a new type of oxygen vacancies enriched cobalt-doped molybdenum oxynitride quantum dot-anchored N-doped carbon nanosheets (V-O-CMON@NCNs) was demonstrated as an advanced air-cathode for long-life rechargeable ZABs. Such V-O-CMON@NCN catalyst has an exceptional ORR performance with a high half-wave potential of 0.857 V and tremendous OER performance with an ultrasmall overpotential of 240 mV at a current density of 10 mA cm(-2), outperforming conventional Pt/C and RuO2 catalysts. As proof of concept, rechargeable ZABs with an optimal V-O-CMON@NCN-800 air-cathode showed an ultrahigh specific capacity of 721.2 mA h g(Zn)(-1) at a current density of 5 mA cm(-2), a tremendous peak power density of 143.7 mW cm(-2), and ultralong cycling life of 500 h. These consequences suggest that the oxygen vacancies enriched V-O-CMON@NCN can serve as promising bifunctional catalysts for next-generation metal-air batteries and other energy-related applications.

Automated summary

The oxygen vacancies enriched V-O-CMON@NCN catalyst has shown exceptional performance as an advanced air-cathode for rechargeable zinc-air batteries, surpassing conventional Pt/C and RuO2 catalysts in both oxygen reduction and oxygen evolution reactions. The rechargeable ZABs with V-O-CMON@NCN-800 air-cathode exhibited high specific capacity, peak power density, and long cycling life, suggesting the potential of V-O-CMON@NCN as promising bifunctional catalysts for next-generation metal-air batteries and other energy-related applications.