Vanadium Sulfide on Reduced Graphene Oxide Layer as a Promising Anode for Sodium Ion Battery.

As an alternative system of rechargeable lithium ion batteries, sodium ion batteries revitalize researchers' interest due to the low cost, abundant sodium resources, and similar storage mechanism to lithium ion batteries. VS4 has emerged as a promising anode material for SIBs due to low cost and its unique linear chains structure that can offer potential sites for sodium storage. Herein, we present the growth of VS4 on reduced graphene oxide (rGO) as SIBs anode for the first time. The VS4/rGO anode exhibits promising performance in SIBs. It delivers a reversible capacity of 362 mAh g(-1) at 100 mA g(-1) and a good rate performance. We also investigate the sodium storage behavior of the VS4/rGO. Different than most transition metal sulfides, the VS4/rGO composite experiences a three-step separation mechanism during the sodiation process (VS4 to metallic V and Na2S, then the electrochemical mechanism is akin to Na-S). The VS4/rGO composite proves to be a promising material for rechargeable SIBs.