Construction of stacked CoS1.097/V3S4 heterojunction nanosheets towards the enhanced reaction kinetics and cycling stability of sodium-ion batteries

In recent years, sodium-ion batteries (SIBs) have gained significant attention as a viable alternative to lithium-ion batteries due to the abundance of sodium, its low cost, and its similar electrochemical behavior compared to lithium. A key approach to enhancing SIB anode performance is designing stable electrode structures that minimize sodium ion-diffusion pathways. In this study, we synthesized a sheet-like stacked CoS_1.097/V₃S₄ heterostructure via a hydrothermal method. The CoS_1.097/V₃S₄ composite combines the high specific capacity of CoS_1.097 with the excellent cycling stability of V₃S₄. Notably, the heterojunction generates an integrated electric field that reduces activation energy, accelerates charge transfer, and enhances reaction kinetics. The CoS_1.097/V₃S₄ heterostructure exhibits an initial discharge capacity of 833.8 mAh g⁻¹ at 0.5 A g⁻¹ and a reversible capacity of 505.8 mAh g⁻¹ after 100 cycles. Impressively, even at a high current density of 5 A g⁻¹, the electrode retains a capacity of 330.8 mAh g⁻¹ after 1000 cycles. This study demonstrates a promising approach for developing SIB anode materials with superior performance, high reversibility, and long-term cycling durability, supported by the synergistic effect of the CoS_1.097/V₃S₄ heterojunction.