Li4Ti5O12 composited with Li2ZrO3 revealing simultaneously meliorated ionic and electronic conductivities as high performance anode materials for Li-ion batteries

摘要

Li4Ti5O12 (LTO) is inherently a poor ionic and electronic conductor, and the modification methods available could solely meliorate either ionic or electronic conductivity. In order to simultaneously improve both the ionic and electronic conductivities, LTO was composited with Li2ZrO3 accompanying with superficial Zr4+ doping by the simple reaction between Zr(NO3)(4).5H(2)O and LiNO3 on the LTO surface. From the comparative experiments, the as-modified LTO with a Li2ZrO3/LTO mass ratio of 0.009 and sintered at 750 degrees C exhibits the most excellent rate performance (achieving capacities of 1553, 149.6, 145.4,139.6,130.2 and 153.2 mAh g(-1) at 100, 200, 400, 800,1600 and 100 mA g(-1), respectively) and long-term cyclability (retaining a capacity of 102 mAh g(-1) after the 2000th cycle at 500 mA g(-1)). By the detailed structural characterization and electrochemical impedance spectra analysis, the formation of the tetragonal Li2ZrO3 with good ionic conductivity and the superficial Zr4+ doping with improved electronic conductivity is responsible for the markedly enhanced cycling and rate performance of LTO. (C) 2017 Elsevier B.V. All rights reserved.