纯相Li4Ti5O12水热合成及其电化学性能

Hydrothermal Synthesis of Pure Li_4Ti_5O_(12)and Its Electrochemical Performance

以纳米级锐钛矿型二氧化钛(TiO2)和氢氧化锂(LiOH)为原料,利用水热法合成了尖晶石型Li4Ti5O12材料,并研究了LiOH浓度、水热反应时间及热处理温度对Li4Ti5O12样品结构和电化学性能的影响,分析了Li4Ti5O12的形成过程.采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)分析样品材料结构,观察材料形貌.结果表明,LiOH浓度0.2 mol.L-1、水热反应时间12 h及煅烧温度700℃可得到纯相尖晶石型Li4Ti5O12,该样品1C倍率放电比容量为146.3 mAh.g-1,40C高倍率其放电比容量仍有101.3 mAh.g-1.

Spinel Li4Ti5O12 was prepared by hydrothermal method using commercial anatase （TiO2） and lithium hydroxide （LiOH） as raw materials. The effects of LiOH concentration, hydrothermal reaction time and calcination temperature on the structure and electrochemical performance of Li4Ti5O12 were investigated. The formation process of Li4Ti5O12 was also proposed. The microstructure and morphology were characterized by XRD, SEM, TEM techniques, and the electrochemical performance was analyzed by galvanostatic charge-discharge test. The results show that the pure phase spinel Li4Ti5O12 can be obtained when the LiOH concentration is 0.2 mol .L^-1, the hydrothermal time is 12 h, and the calcination temperature is 700 ℃. The LiaTi5O12 annealed at 700 ℃ has excellent electrochemical performance. The discharge specific capacity reached 146.3 mall. g^-1 at the current density of 1 C, and exhibited superior high-rate performance of 101.3 mAh-g^-1 at 40C.