Li4Ti5O12 epitaxial coating on LiNi0.5Mn1.5O4 surface for improving the electrochemical performance through solvothermal-assisted processing

摘要

During the charge-discharge of the LiNia(5)Mn(1.5)O(4) (LNMO) cathode in Li-ion batteries, Ni2+ and Mn2+ dissolve in the electrolyte to cause oxidative decomposition, which is the major cause for fast capacity fading and poor cycle performance. Reducing the direct contact area between the cathode material and the electrolyte is a direct solution to improve the cell performance. This paper focuses on a solvothermal method to coat the surface of LiNi0.5Mn1.5O4 hollow microspheres with TiO2 followed by TiO2 conversion into Li4Ti5O12 (LTO) using LiOH center dot H2O. The Li4Ti5O12 coating layer synthesized by this method demonstrates epitaxial growth on the outer surface of LiNia(5)Ma(1.5)O(4). The LTO-coated LNMO cathode exhibits capacity retention of 88.1% after 100 cycles at 0.5C rate, much higher than 62.2% for the bare LNMO counterpart, at elevated temperature of 55 degrees C. In addition, the Lit-ion mobility for the LTO-coated LNMO electrode is increased. (C) 2018 Published by Elsevier B.V.