Ultra-small CoxSy nanoparticles adhered to 3D-reduced graphene oxide as attractive anodes for lithium-ion batteries

Abstract

A novel composite anode material, Co_xS_y/G, has been developed through a novel hydrothermal synthesis method complemented by an innovative high-temperature vulcanization technique. This process facilitates the deposition of CoxSy nanoparticles, each less than 10 nm in size, onto a substrate of 3D rGO. This composite material combines the robust lithium storage capacity of CoxSy nanoparticles with the exceptional electrical conductivity and mechanical resilience of the 3D rGO framework, resulting in a significantly enhanced specific surface area and optimized mesoporous structure for CoxSy/G. Furthermore, it exhibits excellent electrochemical performance in lithium-ion batteries. Specifically, the CoxSy/G composites achieve a discharge capacity of 748.5 mA h g⁻¹ at 50 mA g⁻¹ , notably exceeding the 647 mA h g⁻¹ capacity demonstrated by pure CoxSy. Furthermore, these composites maintain an extraordinary cycle retention rate of 112.4 % after undergoing 500 charge-discharge cycles at a continuous rate of 0.5 A g⁻¹ . The reduced charge transfer resistance noted after cycling underscores the material’s enhanced performance attributes. This innovative creation of CoxSy/G composites offers critical insights and potential strategies for further development in the field of lithium-ion cobalt-sulfur electrodes.