A visible-light-driven CoS2/CuS@CNT-C3N4 photocatalyst for high-performance rechargeable zinc-air batteries beyond 500 mW cm–2

Abstract

ABSTRACT

Storing solar energy in battery systems is crucial to achieving a green and sustainable society. However, the efficient development of photo-enhanced zinc-air batteries (ZABs) is limited by the rapid recombination of photogenerated carriers on the photocathode. In this work, the visible-light-driven CoS₂/CuS@CNT-C₃N₄ photocatalyst with unique petal-like layer structure was designed and developed, which can be used as air electrode for visible-light-driven ZABs. The superior performance of ZABs assembled by CoS₂/CuS@CNT-C₃N₄ was mainly attributed to the successful construction of Schottky heterojunction between g-C₃N₄ and carbon nanotubes (CNTs), which accelerates the transfer of electrons from g-C₃N₄ to CoS₂/CuS cocatalysts, improves the carrier separation ability, and extends the carrier lifetime. Thereinto, the visible-driven ZABs assembled by CoS₂/CuS@CNT-C₃N₄ photocatalyst has a power density of 588.90 mW cm^–2 and a charge-discharge cycle of 643 h under visible light irradiation, which is the highest performance ever reported for photo-enhanced ZABs. More importantly, the charge-discharge voltage drop of ZABs was only 0.54 V under visible light irradiation, which is significantly lower than the voltage drop (0.94 V) in the dark. This study provides a new idea for designing efficient and stable visible-light-driven ZABs cathode catalysts.