Abstract:A sol−gel method using lauric acid as surfactant was used to synthesize Li₄Ti₅O₁₂ nanocrystals with an ultra-fine particle size distribution between 120 and 250 nm. In order to obtain the electrode materials with the best electrochemical performance, the content of lauric acid during Li₄Ti₅O₁₂ synthesis was systematically studied. The physical and electrochemical properties of the synthesized samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), laser particle size analysis, alternating current impedance (AC) and galvanostatic charge-discharge experiments. The highly dispersed Li₄Ti₅O₁₂ nanocrystals obtained at 800 °C for 10 h can deliver a specific capacity of 163.3 mA∙h/g at 1C rate without obvious capacity fade up to 50 cycles. The results suggest that well dispersed Li₄Ti₅O₁₂ nanocrystals shorten the Li-ion diffusion length and enhance the electrochemical kinetics of the samples, which are very crucial to high rate capability.

Key words: lithium-ion battery; lithium titanate; nanocrystals; surfactant; sol-gel method