Synthesis and electrochemical properties of LiV_3O_8 via an improved sol-gel process

摘要

LiV_3O_8 cathode material was synthesized via a hydrothermal improved sol-gel process using LiOH, NH4VO3 and oxalic acid as raw materials. The thermal decomposition process of the as-prepared LiV_3O_8 precursor was investigated by thermogravimetric (TG) and differential scanning calorimetry (DSC). The structure, morphology and electrochemical performance of the as-synthesized LiV_3O_8 samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and the galvanostatic charge-discharge test. The effects of synthesis conditions on phases, structure and electrochemical performance of the LiV_3O_8 samples were particularly discussed. Result shows that pure LiV_3O_8 sample can be obtained at 300 °C, which is much lower than that of normal citric assisted sol-gel method. The sample synthesized at 350 °C exhibits the best electrochemical performance, which can present an initial discharge capacity of 301.1 mAh/g at a current density of 50 mA/g and maintain 271.6 mA/g (about 90.2% of its initial value) after 10 cycles.