A new approach to synthesize MoO2@C for high-rate lithium ion batteries

Abstract

A MoO₂@C nanocomposite was prepared using oleic acid to reduce the MoO₃ precursor and to simultaneously coat the resultant one-dimensional MoO₂ nanorods with carbon layers. The MoO₂@C composite has a mesoporous structure with a surface area of 45.7 m² g⁻¹, and a typical pore size of 3.8 nm. When applied as an anode for lithium ion batteries, the MoO₂@C electrode exhibits not only high reversible capacity, but also remarkable rate capability and excellent cycling stability. A high capacity of 1034 mA h g⁻¹ was delivered at 0.1 A g⁻¹. And at a super-high specific current of 22 A g⁻¹, a capacity of 155 mA h g⁻¹ was still obtained. When cycled at 0.5 and 10 A g⁻¹, the Li/MoO₂@C half cells retained 861 and 312 mA h g⁻¹ capacity after 140 and 268 cycles, respectively. The mesoporous nature of the MoO₂@C nanocomposite and the thin-layer carbon coating are believed to contribute to the enhanced electrochemical performance, which not only feature the efficient four-electron conversion reaction for Li⁺ storage, but also effectively tolerate volume expansion during the cycling.