Structural and electrochemical performances of Li4Ti5−xZrxO12 as anode material for lithium-ion batteries

Zr-doped Li4Ti5O12 in the form of Li4Ti5−xZrxO12 (x = 0, 0.05, 0.1 and 0.2) was prepared by solid-state reaction in an air atmosphere. The dopant Zr partly entered the lattice structure of Li4Ti5O12, and the excessive part existed as the impurity of ZrO2. Zr-doping did not change the electrochemical reaction process of Li4Ti5O12, but greatly affected its morphology and particle size. The particle size of the Zr-doped Li4Ti5O12 sample was less than 100 nm and had less agglomeration. Zr-doping obviously improved the rate capability of Li4Ti5O12 via the generation of small particle size and less agglomeration, however, a high amount of Zr-doping was adverse to the electrochemical performance probably due to much ZrO2 impurity contained in the Li4Ti5O12. Li4Ti4.9Zr0.1O12 exhibited a relatively good rate capability and cycling stability. At the charge–discharge rate of 5C, 10C and 20C, its discharge capacities were 143 mAh/g, 132 mAh/g and 118 mAh/g, respectively. After 100 cycles at 5C, it remained at 141 mAh/g.