锂离子电池负极材料Li_4Ti_5O_(12)的原位水解合成与表征

以TiCl_4水溶液和LiOH·H_2O为原料,采用原位水解与后续热处理相结合的方法制备尖晶石型锂离子电池用负极材料Li_4Ti_5O_(12).结果表明:从TiCl_4水溶液原位水解合成Li_4Ti_5O_(12)经历由TiCl_4→TiO_2→Li_2TiO_3→Li_4Ti_5O_(12) 3个阶段的原位相转变过程;TiCl_4水溶液的浓度及稳定性对合成Li_4Ti_5O_(12)的结构有较大的影响;随着TiCl_4浓度的增加,合成纯Li_4Ti_5O_(12)所需的水解时间延长;以0.5 mol/L TiCl_4水溶液水解1 h、以添加1.0 mol/L LiCl的0.5 mol/L TiCl_4水溶液水解3 h、以1.0 mol/L与1.5 mol/L TiCl_4水溶液水解5 h均可获得纯Li_4Ti_5O_(12);由低浓度TiCl_4水溶液合成的Li_4Ti_5O_(12)循环性能优良.

Synthesis and characterization of Li_4Ti_5O_(12) anode material for lithium ion batteries via in-situ hydrolysis

Spinel Li_4Ti_5O_(12) as an anode material for lithium ion batteries was synthesized via in-situ hydrolysis followed by heat treatment using aqueous TiCl_4 solution and LiOH·H2O as the raw materials. The results show that the synthesis of Li_4Ti_5O_(12) from aqueous TiCl_4 solution by in-situ hydrolysis consists of three-step in-situ phase transformation, that is TiCl_4→TiO_2→Li_2TiO_3→Li_4Ti_5O_(12). The concentration and stability of aqueous TiCl_4 solution have significant effects on the synthesis of Li_4Ti_5O_(12). With increasing TiCl_4 concentration, the hydrolysis time of TiCl_4 for the formation of Li_4Ti_5O_(12) increases. The optimal hydrolysis time for the synthesis of pure Li_4Ti_5O_(12) from TiCl_4 solutions with different Ti(Ⅳ) concentrations is found to be 1 h for 0.5 mol/L TiCl_4, 3 h for 0.5 mol/L TiCl_4 with addition of 1.0 mol/L LiCl and 5 h for both 1.0 mol/L and 1.5 mol/L TiCl_4. The products prepared from lower Ti(Ⅳ) concentration solutions show excellent cycling performance.