Abstract:Zr4+ doped Li4Ti5O12 was synthesized from Li2CO3, ZrO2 and tetrabutyl titanate by a modified solid-state method. The effects of the in-situ coating, high energy ball-milling and Zr-doping on crystalline structure, particle size, morphology and electrochemical performance of Li4Ti5O12 were investigated. The samples were tested by XRD, SEM and electrochemical workstation. The results show that the in-situ coating and ball-milling can decrease the particle size and prevent the aggregation of nanoparticles. Zr-doping obviously improves the rate capability of Li4Ti5O12 via the generation of less electrode polarization and higher Li+ diffusion coefficient. Li4Ti4.95Zr0.05O12 exhibits an excellent rate capability and cycling stability. At the charge-discharge rate of 0.5 and 40C, its discharge capacities are 176 and 52 mAh·g-1, respectively. After 10 cycles, there is less than 0.5% reduction in reversible capacity at 1, 2, 5, 10, 20 and 40 C. Compared to Ce-doping, it also shows better crystallization and electrochemical performance due to its smaller ionic radius.