Lithium reaction mechanism and high rate capability of VS4-graphene nanocomposite as an anode material for lithium batteries

A graphene-attached VS4 composite prepared by a simple hydrothermal method is studied in terms of its lithium reaction mechanism and high rate capability. The nanocomposite exhibits a good cycling stability and an impressive high-rate capability for lithium storage, delivering a comparable capacity of 630 and 314 mA h g(-1), even at high rates of 10 and 20 C (=10 and 20 A g(-1), or 10 and 20 mA cm(-2)), respectively. In addition, full-cell (LiMn2O4/VS4-graphene) test results also exhibited a good capacity retention. The mechanism of Li storage is systematically studied and a conversion reaction with an irreversible phase change during the initial discharge-charge process is proposed.