Bimetallic Sulfide SbS/FeS Heterostructure Anchored in a Carbon Skeleton for Fast and Stable Sodium Storage.

Sodium-ion batteries (SIBs) are a promising substitute for lithium batteries due to their abundant resources and low cost. Metal sulfides are regarded as highly attractive anode materials due to their superior mechanical stability and high theoretical specific capacity. Guided by the density functional theory (DFT) calculations, 3D porous network shaped SbS/FeS composite materials with reduced graphene oxide (rGO) through a simple solvothermal and calcination method, which is predicted to facilitate favorable Na ion diffusion, is synthesized. Benefiting from the well-designed structure, the resulting SbS/FeS exhibit a remarkable reversible capacity of 536 mAh g after 2000 cycles at a current density of 5 A g and long high-rate cycle life of 3000 cycles at a current density of 30 A g as SIBs anode. In situ and ex situ analyses are carried out to gain further insights into the storage mechanisms and processes of sodium ions in SbS/FeS@rGO composites. The significantly enhanced sodium storage capacity is attributed to the unique structure and the heterogeneous interface between SbS and FeS. This study illustrates that combining rGO with heterogeneous engineering can provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs.