METHOD FOR PREPARING AN ELECTRODE ACTIVE MATERIAL FOR IMPROVING THE PROPERTIES OF A BATTERY, AND LITHIUM SECONDARY BATTERY INCLUDING THE ELECTRODE ACTIVE MATERIAL PREPARED THEREBY
A method of preparing an electrode active material for manufacturing a lithium secondary battery exhibiting stable charging/discharging efficiency and life-cycle characteristics even during high-speed charging/discharging cycles is provided. Also, a method of controlling both a composition ratio (Ti/Li) of surface elements and a composition of a lithium element in a lithium titanium oxide which is known to be an electrode active material having a relatively stable structure is provided. The lithium secondary battery using the lithium titanium oxide manufactured by the method as the electrode active material can be stably used by maintaining charging/discharging efficiency and charging capacity even during the high-speed charging/discharging cycles.
1 . A method of preparing a lithium titanium oxide (LTO), wherein a composition ratio (Ti/Li) of a titanium element to a lithium element in a surface of the LTO is controlled to be greater than or equal to 0.8.
2 . The method of claim 1 , wherein a composition of the lithium element in the surface of the LTO is controlled to be less than 20%.
3 . The method of claim 1 , comprising:
mixing a lithium compound and a titanium compound; and
thermally treating the reaction mixture at a temperature of 700° C. to 900° C. for 4 to 8 hours.
4 . The method of claim 3 , wherein the mixing of the lithium compound and the titanium compound is performed by introducing the lithium compound and the titanium compound into a solvent and stirring the lithium compound and the titanium compound in a slurry phase.
5 . The method of claim 3 , wherein the mixing of the lithium compound and the titanium compound is performed by uniformly mixing the powdery lithium compounds and titanium compounds.
6 . The method of claim 3 , wherein the thermal treatment of the reaction mixture is performed in a closed container under a general ambient atmosphere.
7 . A lithium secondary battery comprising the lithium titanium oxide (LTO) prepared by the method of claim 1 as an electrode active material.