In situ constructed bimetallic sulfide heterostructures on 3D graphene for efficient lithium storage

Abstract

Metal sulfides are receiving increasing interest for lithium-ion batteries owing to their good reaction reversibility and high reversible theoretical capacity. However, their development still stays at the infancy stage due to the low conductivity and the volume change during charging and discharging processes, resulting in poor rate performance and cycling stability. Herein, a bimetallic sulfide heterostructured SnS/CoS embedded in reduced graphene oxide substrate (SnS/CoS@rGO) is designed by an ingenious design of a one-step method. The rich interphase boundaries in SnS/CoS heterostructures can significantly improve ionic and electronic diffusion kinetics because of the built-in electric field. In addition, the three-dimensional rGO substrate provides extra efficient transfer paths for electrons and ions, and can buffer volume changes to maintain outstanding structural stability. As a result, the SnS/CoS@rGO electrode exhibits high reversible capacity of 1223 mAh g⁻¹ after 400 cycles at a current density of 500 mA g⁻¹. Even at a current density of 1 A g⁻¹, the capacity remains at 846 mAh g⁻¹ after 400 cycles.