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Powder Technology, Volume 247, October 2013, Pages 204-210.
Wei Liu a, b, Jian Zhang a, Qian Wang a, b, Xiaohua Xiea, Yuwan Lou a, b, Xuewu Han a, Baojia Xia a, b
a- Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China and
b-University of Chinese Academy of Sciences, Beijing 100049, China.
Abstract
Microsized TiO2 activated by high-energy ball milling was used as starting material to synthesize spinel Li4Ti5O12 by a conventional solid-state method. The effects of TiO2 particle size on the structure, morphology and electrochemical performance of Li4Ti5O12 were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and electrochemical tests. The results indicate that the particle size and degree of crystallinity of TiO2 are significantly reduced by the mechanical activation of high-energy ball milling. The crystalline structure and morphology of Li4Ti5O12 highly depend on the properties of TiO2. The optimal Li4Ti5O12 sample exhibits a high rate capability of about 103.9 mAh/g at 10C rate and excellent cyclability at 1C rate, which could be ascribed to the smaller particle size and higher lithium-ion diffusion coefficient. Therefore, the microsized TiO2 activated by high-energy ball milling is suitable for the economic synthesis of Li4Ti5O12.
Additional information
As is well-known, Li4Ti5O12 anode material shows rapid charging-discharging, long life and high safety, compared with graphite anode material. But the price of Li4Ti5O12 (about 20-25 $/kg) is much higher than that of graphite (about 5-10 $/kg). In our opinion, using micro-sized TiO2 as starting materials is an efficient way to reduce the preparation cost of Li4Ti5O12. After activated by high-energy ball milling, micro-sized TiO2 has lower degree of crystallinity and smaller particle size, which is beneficial for the synthesis of Li4Ti5O12. We have investigated the effect of particle size of micro-sized TiO2 on the structure, morphology and electrochemical properties of Li4Ti5O12 in details. The rate capability synthesized by micro-sized TiO2 is even better than the samples synthesized by nano-sized TiO2 reported by other authors. It can be seen that micro-sized TiO2 activated by high energy ball milling is suitable for the economic synthesis of Li4Ti5O12 with good rate capability and cycle stability. Thus, this work may contribute to the industrial application of Li4Ti5O12.
