Preparation And Performance Research Of Lithium Ion Battery Anode Material Li₄Ti₅O₁₂

Spinel Li4Ti5O12 is a promising lithium ion battery anode material. It has some evident advantages:there is negligible volume change during charge/discharge process (the so-called "zero-strain insertion material"), so it possesses excellent reversibility; its Li-insertion potential is at about 1.55V vs. Li+/Li, which is high than the reduction voltage of common electrolyte; the diffusion coefficient is 2×10-11 cm2/s, so it has excellent lithium ion mobility that promising for high-rate battery applications. Furthermore, this material accommodates Li+ with theoretical capacity of 175 mAh/g. Compared with graphite anode material, Li4Ti5O12 is considered to be of better rate performance and safety.Anatase TiO2 and Li2CO3 were used as raw material to synthesize Li4Ti5O12 by solid-state method to study the optimal synthesis conditions of Li4Ti5O12. The moral ratio of n(Li)/n(Ti) was 0.84. Water was used as dispersant and ball-milling was used as mixing method. The result showed that the optimal synthesis conditions of Li4Ti5O12 were sintering 12h under 800℃. The initial discharge capacity at 0.5C was 135.8 mAh/g.Li4Ti5O12/C composite was prepared with the optimal synthesis conditions above and Li-citrate was used as carbon source and part of lithium source. The average particle size of as-prepared material was 70nm, while that of virgin Li4Ti5O12 synthesized under the same conditions was 600nm. The material showed excellent electrochemical performances, especially high-rate performances. The initial discharge capacity at 20C was 121.1 mAh/g, and after 100 cycles, it was still 106.1 mAh/g.PITT method was used to measure Li+ diffusion coefficient of Li4Ti5O12. The result showed that DLi+, ranged from 10-12 to 10-10cm2s-1 at various electrode potentials; core/shell structure was formed during charging/discharging process.