LITHIUM TITANATE COMPOSITE MATERIAL, PREPARATION METHOD THEREOF, NEGATIVE ACTIVE SUBSTANCE AND LITHIUM ION SECONDARY BATTERY CONTAINING THE SAME

摘要

Provided is a composite material having spinel structured lithium titanate, wherein the lithium titanate has a microcrystalline grain diameter of about 36-43 nm and an average particle diameter of about 1-3 μm. The composite material comprises a small amount of TiO2 and Li2—TiO3 impurity phases. Also provided is a method for preparing the composite material, which comprises the steps: mixing titanium dioxide particles and soluble lithium sources with water to form a mixture, removing water and then sintering the mixture in an inert gas at a constant temperature, and cooling the sintered mixture, wherein the titanium dioxide particles have D50 of not greater than 0.4 μm and D95 of less than 1 μm. Further provided are a negative active substance comprising the composite material and a lithium ion secondary battery containing the negative active substance.