Electrochemical performance and Li+ insertion/extraction mechanism of carbon-coated cerium metavanadate as a novel anode for lithium-ion batteries

Abstract

The novel CeVO3 anode material is synthesized successfully by simple sol-gel method. The crystal structure is determined by the X-ray diffraction, where the CeVO3 possesses a stable framework and a good lithium-ion migration pathway. The corresponding electrochemical measurement shows that pure CeVO3 presents a low reversible discharge capacity and poor rate performance due to the low electronic conductivity. In order to improve the electrochemical properties, the carbon-coated CeVO3 samples are also prepared choosing sucrose as carbon source with 9.5% carbon content. The added carbon inhibits the particle growth and increases the conductivity. By carbon-coating, the corresponding electronic conductivity of the CeVO3 is increased by one order of magnitude and the lithium diffusion coefficient is increased from 6.55 × 10−11 cm2 s−1 to 2.26 × 10−10 cm2 s−1, resulting in the improvement of discharge specific capacity and rate performance. In addition, using In-situ XRD method, we determine the Li ions insertion/extraction mechanism of the CeVO3 material which can be interpreted as a solid-solution behavior. Finally, using nudged elastic band method, we calculate the possible migration paths for lithium diffusion in CeVO3 crystal which most likely prefers to along the diagonal direction of z axis and x axis.