Facile self-assembly of carbon-free vanadium sulfide nanosheet for stable and high-rate lithium-ion storage

Metal sulfides are recognized as potential candidates for the anode materials of lithium ion batteries (LIBs) because of their high theoretical capacity. However, the low reaction kinetics of metal sulfides leads to their poor cycle life and rate performance, which limits their practical application in the field of energy storage. In this work, we synthesized a self-assembled carbon-free vanadium sulfide (V₃S₄) nanosheet via a facile and efficient method. The unique mesoporous nanostructure of V₃S₄ can not only accelerate the migration of ions/electrons, but also alleviate the volume expansion during the lithium ion insertion/extraction process. When used as the anode material of LIBs, the carbon-free V₃S₄ electrode exhibits remarkable electrochemical performance with ultra-high charge capacity (1099.3 mAh g^-1 at 0.1 A g^-1), superior rate capability (668.8 mAh g^-1 at 2 A g^-1 and 588.8 mAh g^-1 at 5 A g^-1) and impressive cycling ability (369.6 mAh g^-1 after 200 cycles at 10 A g ^-1), which is very competitive compared with those of most metal sulfides-based anode materials reported so far. The strategy in this work provides inspiration for the rational design of advanced nanostructured electrode materials for energy storage devices.