The Research Of The Preparation And Electrochemical Performance Of Anode Materials Li₄Ti₅O₁₂/TiN For Lithium Ion Batteries

Spinel Li₄Ti₅O₁₂has drawn extensive attention due to its easy preparation, low rawmaterial cost, environmental friendliness and excellent safety.In this dissertation, Li₄Ti₅O₁₂was synthesized by a solid-state reaction methodthrough the different calcined way. The sample that was prepared by a calcined way ofdirect-take-direct-put in a muffle furnace and calcined30minutes exhibits a bestelectrochemical performance.In order to improve the rate performance of the Li₄Ti₅O₁₂, through heat treatmenton Li₄Ti₅O₁₂with urea as nitrogen source, little blue Li₄Ti₅O₁₂/TiN was prepared. Thefact that no characteristic peaks of TiN could be detected in the XRD spectra, indicatethat only a thin layer or small amount of TiN is formed on the surface of the Li₄Ti₅O₁₂.The TiN was formed on the surface of Li₄Ti₅O₁₂sample, which was also confirmed byRaman spectroscopy and HR-TEM. The existence of TiN has positive impact on theelectronic conductivity of Li₄Ti₅O₁₂sample, was also proved by EIS. Electrochemicalperformance results show that: the rate capability and cycle-life of Li₄Ti₅O₁₂/TiN hasgreatly improved, the electrochemical performance is the best when6%urea added. Thedischarge capacity is115.4mAh/g at a charge and diacharge rate of10C.After684cycles at a rate of3C, the discharge capacity is140.3mAh/g and the capacity retentionrate is85%.The Li₄Ti₅O₁₂sample was prepared by the spray drying method, Electrochemicalperformance results show that: the sample that was synthesized by this method has goodelectrochemical properties than the sample that was synthesized by ball grindingmethod.