Li2ZrO3-coated Li4Ti5O12 with nanoscale interface for high performance lithium-ion batteries

Zr doped sample of Li4Ti4.99Zr0.01O12 (LZTO) and Li2ZrO3 (LZO) coated Li4Ti5O12 (LTO) are prepared by a solid-state method. The lattice structure of LTO is remained after doping element of Zr and coating layer of LZO. The crystal structure and electrochemical performance of the material are investigated by X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM), cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT) and charge-discharge tests, respectively. Zr-doping and LZO coating play the positive role in improving the diffusion ability of lithium cations. LZTO and LZO-LTO show much improved specific capacity and rate capability compared with pristine sample of LTO. LZO-LTO has the smallest voltage differential (Delta V) of the redox peaks because the coating of Li2ZrO3 is helpful for the diffusion ability of lithium ions during charge/discharge processes. LZTO and LZO-LTO as electrode deliver the initial capacities of 164.8, 168.1 mAh g(-1), respectively, which are much higher than 150.2 mAh g(-1) of intrinsic sample of LTO. Even at the current density of 2 A g(-1), LTZO and LZO-LTO offer capacity of 96 and 106 mAh g(-1), which are much higher than 33 mAh g(-1) of LTO. The improved electrochemical performance is attributed to the improved diffusion ability of lithium. During the whole discharge process, the lowest value of LTO is 5.97 x 10(-17) cm(2) s(-1) that is much lower than 7.80 x 10(-16) cm(2) s(-1) in LZTO and 1.85 x 10(-15) cm(2) s(-1) in LZO-LTO, respectively. (C) 2016 Elsevier B.V. All rights reserved.