WANG Yaping 1, 3, NAN Hui 2, YANG Pan 3, ZHAO Xiaochong 3, LAI Xinchun 3, WANG Gang 1
(1. Institute of Chemical Engineering, Qinghai University, Xining 810016, Qinghai, China; 2. Institute of Mechanical Engineering, Qinghai University, Xining 810016, Qinghai, China; 3. Science and Technology on Surface Physics and Chemistry Laboratory,Mianyang 621907, Sichuan, China)
Abstract:Lithium-ion battery is one of secondary batteries with the best comprehensive properties. In this paper, lithium titanate nanoparticles are prepared via a solvothermal method. The influences of Ti-Li ratio, solvent thermal treatment temperature, and calcination temperature on material structure are studied systematically. X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and galvanostatic current charge-discharge test are applied to analyze the crystallinity, morphology and electrochemical performance of spinellithium titanate. It is found that the calcination temperature plays the key role to synthesis of the spinel-lithium titanate. When calcined at 800 ℃, the as-prepared samples show uniform size, high crystallinity and purity of Li4Ti5O12 phase. A specific discharge capacity is around 107 mAh/g at a rate of 3C, and still remains 70 mAh/g after 100 cycles, which has less than 0.35% discharge capacity loss. In addition, the coulombic efficiency is close to 100% after 50 cycles, showing good high-rate charge-discharge properties and cycle stability performance.
Key words: lithium-ion battery; spinel-lithium titanate; solvothermal method; nanoparticles