Preparation and electrochemical lithium storage properties of Cu2SnS3@C nanocomposites

Abstract

Cu₂SnS₃, recognized as a conversion and alloy type anode material for lithium-ion batteries, possesses a high theoretical specific capacity of 784 mAh g⁻¹ and exhibits a distinct lithium storage mechanism. However, its intrinsically low electrical conductivity and pronounced volume expansion during cycling pose significant challenges to its practical battery performance. To address these limitations, Cu₂SnS₃@C (CTS@C) nanomaterials were synthesized by a one-step microwave-assisted method, utilizing ethylene glycol as a solvent and glucose as a carbon precursor. The incorporation of a carbon coating has been demonstrated to markedly improve the conductivity of the material and mitigate the volume expansion associated with lithium insertion and extraction. Electrochemical tests revealed that the CTS@C electrode exhibits superior electrochemical performance. Specifically, the CTS@C electrodes exhibited an initial discharge capacity of 612.8 mAh g⁻¹, with a retention of 295.8 mAh g⁻¹ after 500 cycles at a current density of 500 mA g⁻¹. The carbon coating not only effectively enhances the conductivity of the electrode material, but also accelerates the electrochemical reaction rate, and enhances the diffusion rate of lithium ions, thereby significantly improving the electrochemical performance of the battery.