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

Abstract

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.