A Facile Process for Surface Modification with Lithium Ion Conducting Material of Li2TiF6 for LiMn2O4 in Lithium Ion Batteries

Abstract

A facile method for surface coating with Li2TiF6 which has a high lithium-ion conductivity, on LiMn2O4 spinel cathode material for high performance lithium ion batteries. The surface coating is performed by using a co-precipitation method with Li2CO3 powder and H2TiF6 solution under room temperature and atmospheric pressure without special equipment. Total coating amount of Li2TiF6 is carefully controlled from 0 to 10 wt.% based on the active material of LiMn2O4. They are evaluated by a systematic combination of analyses comprising with XRD, SEM, TEM and ICP. It is found that the surface modification of Li2TiF6 is very beneficial to high cycle life and excellent rate capability by reducing surface failure and supporting lithium ions transportation on the surface. The best coating condition is found to have a high cycle life of 103 mAh g(-1) at the 100th cycle and a rate capability of 102.9 mAh g(-1) under 20 C. The detail electrochemical behaviors are investigated by AC impedance and galvanostatic charge and discharge test.