Synthesis and electrochemical properties of highly dispersed Li4Ti5O12 nanocrystalline for lithium secondary batteries
(1. College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009, China;
2. National Engineering Research Center for Nanotechnology, Shanghai 200241, China)
2. National Engineering Research Center for Nanotechnology, Shanghai 200241, China)
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