Lithium-ion Battery Anode Material For Li <sub> 4 </ Sub> Ti <sub> 5 </ Sub> The O <sub> 12 </ Sub> Of Preparation And Performance

The spinel Li4Ti5O12 has been demonstrated as one of the most promising anode material candidates for lithium ion batteries, due to its excellent cyclability, very good safety, easy preparation, environmental friendliness and so on. However, a major obstacle to its commercial application is the low conductivity of Li4Ti5O12 which exhibited poor rate performance. In the paper, pure Li4Ti5O12 was symhesized by different methods and the rate performance of Li4Ti5O12 was improved by coating substance which has good conductivity.Spinel Li4Ti5O12 was synthesized by solid state reaction using Li2CO3 and TiO2 as raw materials for 850℃,12 hours. The results showed that particle of Li4Ti5O12 were dense and the particle size was 1～4μm. The initial discharge capacity of the cell was 145.4 mAh/g, it retained 80% after 100 cycles.The effect of sintering temperature, sintering time, Li materials and polyethylene glycol(PEG) to Li4Ti5O12 which synthesized by sol-gel method were studied. The XRD test indicated that the spinel lithium titanate composite Li4Ti5O12 was successfully synthesized. The charge-discharge test showed that the capacity of Li4Ti5O12 was increased with elevation of heating temperatures and time. However, the capacity of Li4Ti5O12 was fall when the temperature over 700℃and the time over 6 hours. The particle was smaller, more disperse when using lithium than CH3COOLi·2H2O. By adding PEG to improve the dispersivity and the specific surface area of the Li4Ti5O12, the electrode-electrolyte contact area was increased; meanwhile, more homogeneous mixing of the active materials with carbon black was achieved. Thus the high rate performance of Li4Ti5O12 was improved. Therefore, the ideal experiment parameters are 700℃,6 hours, using lithium as raw materials, and adding PEG as a dispersant.The rate performance of Li4Ti5O12 was improved by coating carbon, TiN and antimony doped Tin oxide(ATO) which increased the electronic conductivity of Li4Ti5O12. The results showed that initial discharge capacity of the cell was increased. When tested at a rate of 5C, they still retained a discharge capacity of 127.3 mAh/g,111.0 mAh/g,88.1 mAh/g, respectively, after 10 cycles, better than 76.0 mAh/g of the pure Li4Ti5O12 Obviously, the material coating carbon got the best performance, and the rate performance of Li4Ti5O12 by coating antimony doped Tin oxide(ATO) was not obvious.