Investigation On Synthesis And Modification Of Li₄Ti₅O₁₂ As The Anode Material For Lithium-Ion Batteries

Due to the advantages of no-pollution, high power density, low self-discharge, lithium-ion battery has been widely applicated in the fields of mobile telephone, portable electronic products, and hybrid kinetic vehicles. Li4Ti5O12 used as lithium-ion battery anode material has a spinel structure, it is a kind of insertion electrode material. It has been regarded as the most promising cathode material in the lithium-ion battery result from its high stability, fast charge-discharge and high security.In this paper, the phylogeny, structure and work principium of lithium-ion batteries were summarized. The lithium-ion battery materials containing cathode and anode materials were introduced. The material characteristics, construction and lithium insertion mechanism, merits and drawbacks, synthesis methods and application of anode material Li4Ti5O12 were generally described. In the experiment,the Li4Ti5O12 samples were obtained by sintering Li2CO3 and amorphous TiO2 at different temperatures for 16h..The results of TG-DSC, XRD and SEM analysis showed that the calcination temperature should be mastered in 800℃～900℃to obtain pure Li4Ti5O12 phase. In contrast of the performance of Li4Ti5O12 samples seperately perapared by Li2CO3 and LiNO3, it can be detected that Li2CO3 was the optimal original lithium material.The Li4Ti5O12 samples perapared by sintering Li2CO3 and anatase TiO2 with variational value of Li/Ti at different temperatures for 16h were measured by electrochemical performance test, XRD and SEM. It confirmed that the electrochemical peformance, crystal structure and surface morphology were changed along with the increasing content of lithium, and the Li4Ti5O12 sample with 2% excessive Li calcinated at 875℃had the best capability.Because of low inherency conductivity of Li4Ti5O12 material, for the sake of enhancing its capability, the electronic conductivity and ion conductibility should be improved by modification. In this experiment, carbon coating and Mg-doping were used to modify the Li4Ti5O12 samples including different Li content..The electrochemical performance research, phase construction and morphology characterization were performed on the products. In conclusion, the charge-discharge capacibility of Li4Ti5O12/C sample changed a little while the impedance was 10 times more than Li4Ti5O12 sample resulting into reduce the conductivity and diffusion speed of Li ion. And, falling charge-discharge capacity, increasing impedance and particle size were reflected in the Mg-doping Li4Ti5O12 samples while the content of Mg dopped in the samples increased. Contrastively, the sample obtained at 875℃with 1% Mg relative to Li has the best performance.