Enhancing the performance of Li sub(3)VO sub(4) by combining nanotechnology and surface carbon coating for lithium ion batteries

With a large capacity and low voltage, Li sub(3)VO sub(4) has recently attracted much attention as a new insertion-type anode material for lithium-ion batteries. However, the poor electronic conductivity of Li sub(3)VO sub(4) leads to a large amount of inactive conduct agents in the electrode, which definitely sacrifice the electrode capacity and limit the rate performance. In this work, we propose a strategy in which Li sub(3)VO sub(4) is first broken into nanometer scale particles by high energy ball milling to increase the active surface and shorten the Li super(+) diffusion distance, and then the particle surface was homogeneously coated with nanolayered carbon viaa chemical vapor deposition (CVD) method for electronic conductivity enhancement. The obtained nanosized Li sub(3)VO sub(4) is uniformly coated by similar to 5 nm carbon layers. Compared to the untreated counterpart, the modified Li sub(3)VO sub(4), dued to the synergetic effects of the nanometer scale and the carbon coating, exhibits an increased first Coulombic efficiency from 68.8% to 79.5%, a higher reversible capacity from 225 to 315 mA h g super(-1) and a superior rate performance. Importantly, the carbon-coated nanosized Li sub(3)VO sub(4) with only 5% conductive additive exhibits better performances than the microsized raw Li sub(3)VO sub(4) with 10% conductive additive, showing the important effects of particle size and electronic conductivity on the electrochemical properties of Li sub(3)VO sub(4).