Effect of treated temperature on structure and performance of LiCoO2 coated by Li4Ti5O12

The Li4Ti5O12 (LTO)-coated LiCoO2 powders treated at different temperatures (t = 500, 600, 700 and 900 °C) and coated contents (x = 0, 3%, 5%, 10% and 15%) were prepared. The effects of treated temperatures on structure and performance of LiCoO2 coated by LTO particles have been investigated by X-ray diffraction (XRD) and the galvanostatic charge–discharge test at the high upper voltage limit of 4.5 V. 3 wt.% and 5 wt.% LTO-coated materials expose the absence of secondary phase peaks in the range of the diffraction patterns below 700 °C, and distinct additional peaks start appearing when the treated temperature arrives at 900 °C. The diffraction patterns of the 15 wt.% LTO-coated LiCoO2 shift toward higher angles compared to the other coated and bare LiCoO2. The 3 wt.% LTO-coated LiCoO2 cathodes treated at 500, 700 and 900 °C exhibit discharge capacities of 157, 162 and 140 mAh g− 1, respectively, versus capacities of 82 mAh g− 1 for the uncoated cathodes after 40 cycles. The LTO coatings are shown to suppress the capacity fade by reducing cell polarization.