锂离子二次电池负极材料Li_4Ti_(5-x)V_xO_(12)的合成及其电化学性能研究

Synthesis of Li_4Ti_(5-x)V_xO_(12) as an Anode Material for Lithium-ion Secondary Battery

为了提高锂离子二次电池负极材料Li_4Ti_5O_(12)的能量密度,本研究以LiOH·H_2O、TiO_2、NH_4VO_3为原料,采用水热法合成了一系列Li_4Ti_(5-x)V_xO_(12)(0≤x≤0.20)材料。对所合成的材料进行的分析测试表明,800℃是合成Li_4Ti_(5-x)V_xO_(12)(0≤x≤0.20)最适宜的热反应温度。实验结果还表明,钒掺入Li_4Ti_5O_(12)后,材料仍然保持了尖晶石型结构;同时材料的循环稳定性依然优越,且大倍率充放电特性得到显著改善。因此,与Li_4Ti_5O_(12)材料相比,钒掺杂的Li_4Ti_(5-x)V_xO_(12)材料具有更佳的倍率性能和更高的能量密度,更适用于动力锂离子电池。

With the attempt to raise the energy density of Li4Ti5O12, a prospective anode material for LIB, a series of vanadium-doping materials Li4Ti5-xVxO12（0≤x≤0.20） were synthesized by a hydrothermal method. LiOH·H2O, TiO2, and NH4VO3 were used as raw materials, which were mixed in different ratios and processed at several temperatures respectively. Results of analysis indicate that 800 ℃ is the most appropriate pyroreaction temperature. XRD shows that the V-doping materials keep pure spinel structure as Li4Ti5O12. According to the data obtained from electrochemical test, the cycling performance of the as-prepared materials Li4Ti5-xVxO12（0≤x≤0.20） is still superior and their rate capability is improved. In conclusion, it is found that conlpared with Li4Ti5O12, the vanadiun3-doping materials Li4Ti5-xVxO12 as-prepared in this study can substantially enhance the density and rate capability oflithiunl-ion batteries.