Effects of different carbon coatings on the ion transport mechanism and electrochemical performance of Li4Ti5O12 anode for Lithium ion batteries

Li4Ti5O12 (LTO) nanoparticles coated with two types of carbon were synthesized for the anode of lithium ion batteries (LIBs). One type was LTO coated with crystalline carbon from graphite-based mesocarbon microbeads (LTO-MCMB), and the other type was LTO coated with amorphous carbon (LTO-AMC). Transmission electron microscopy (TEM) results indicate that MCMB and amorphous carbon were uniformly coated on the LTO nanoparticles surface using a facile solid-state synthesis method. Electrochemical characterization results show that the rate capability and cycle performance of LTO-MCMB were better than those of LTO-AMC. For example, at an extremely fast charge and discharge rate of 20C (similar to 3 min charge or discharge), LTO-MCMB with 3 wt% MCMB still maintained a high specific capacity of 117 mAh g(-1), compared with 91 mAh g(-1) for LTO-AMC, demonstrating that particle surface engineering at the nanoscale is an efficient method to improve the energy storage performance of the anode material.