Vanadium sulfide embedded in carbon fibers via electrospinning for high performance potassium-ion batteries with enhanced cycling stability

Abstract

Vanadium sulfide is regarded as a promising anode material for potassium-ion batteries (PIBs) owing to its high theoretical specific capacity. However, the capacity fades rapidly owing to the large volume variations accompanied by the insertion and extraction of potassium ions into/from vanadium sulfide. To solve these issues, we confined vanadium sulfide into carbon fibers via the electrospinning method, where the vanadium sulfide distributes homogeneously in the carbon fibers, which will accommodate the volume change. Consequently, a specific capacity of 430 mAh g⁻¹ can be achieved at a current density of 100 mA g⁻¹ after 100 cycles for vanadium sulfide in PIBs, which is much higher than that of pure vanadium sulfide (187 mAh g⁻¹). Even after 300 cycles at a high current density of 2 A g⁻¹, the specific capacity can still be maintained at 315 mAh g⁻¹. These results demonstrate that confining vanadium sulfide into carbon fibers is an effective method to improve the electrochemical performance, which can also be applied to other anode materials of PIBs.