Enabling High Initial Coulombic Efficiency for Li-ion Storage via 3D SnS2@rGO Anode With Tailorable Cavity Size

Abstract

The construction of a 3D conductive structure with cavities is an effective strategy to suppress volume change and shuttle effect of tin sulfide materials during lithium storage, while the influence of cavity size on its electrochemical properties is yet to be clarified due to the lack of controllable methods. Herein, a 3D network-structured hybrid material is reported by a template-induced self-assembly strategy, featuring adjustable spherical cavities with uniformly anchored ultrafine SnS₂ nanosheets inside (3D-SnS₂@rGO), which allows for an ideal cavity volume occupancy rate of 98%. Moreover, the integrated and interconnected 3D cavity structure raises lithium-ion diffusion kinetics and provides transport pathways for electrons. The optimal 3D-SnS₂@rGO material demonstrates superior initial coulombic efficiency (ICE) of 88% and a notable reversible capacity of 1274 mAh g⁻¹ at 0.5 A g⁻¹ along with an excellent capacity retention rate of 102% over 340 cycles. Even after 1000 and 2500 cycles at the current densities of 1 and 5 A g⁻¹, it maintains capacities of 910 and 410 mAh g⁻¹, indicating outstanding volume adaptability and space utilization. Additionally, this facile method can be applied to synthesize other high-performance anode materials (such as MoS₂) with similar integrated 3D structure and high ICE, indicating its good scalability.