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Spinel lithium titanate Li4Ti5O12 material has excellent cycle life, good safety performance, ease of preparation, environmental friendly, is considered to be the most promising one of the anode material of lithium-ion batteries. However, Li4Ti5O12 material due to the low conductivity magnification poor performance, to become the biggest obstacle of its commercial application. In this paper on the basis of the preparation of pure phase Li4Ti5O12 material, by surface modification to improve the performance of the magnification. The Li2CO3 and Ti02 raw material calcined at 850 ℃ for 12 hours spinel Li4Ti5O12 anode materials were prepared by high temperature solid-phase method. Experimental results show that: Li4Ti5O12 particles synthesized compacting and stacked together, uneven grain size distribution, particle diameter of about 1-4 microns, the initial discharge capacity of the test battery for 145.4mAh / g, the capacity retention rate after 100 cycles of approximately sol - gel prepared Li4Ti5Ol2 anode material, 80% of the calcination temperature, holding time, different lithium salts and dispersant polyethylene glycol (PEG) on the electrochemical properties of Li4Ti5O12. The XRD tests show prepared Li4Ti5Ol2 spinel structure; galvanostatic charge-discharge tests show that synthetic Li4Ti5O12 discharge capacity increases with the calcination temperature and holding time, but when the calcination temperature is higher than 700 ℃, holding time more than 6h, the specific discharge capacity of the product but decreased; using lithium metal than the lithium acetate, lithium source synthesis Li4Ti5O12 material particles, high discharge capacity, serious agglomeration; using polyethylene glycol (PEG) as a dispersant, effectively prevents the agglomeration of the particles grow up, thereby improving the the agglomeration caused due to the smaller particles of material and improve the Li4Ti5012 the dispersibility of the particles of the material and specific surface area, not only increases the electrode - electrolyte contact area, the mixing of the active material and the carbon black is also more uniform, thereby improving the Li4Ti5O12 material magnification performance. The optimum conditions: lithium metal, lithium source, polyethylene glycol (PEG) as a dispersing agent, the calcination temperature of 700 ° C, holding time of 6h. Synthetic material using this process for the first time specific discharge capacity for 168.3mAh / g after 100 cycles, the capacity retention rate of 97%, better than the high-temperature solid-phase material prepared by electrochemical performance. Li4Ti5O12 material surface coated with a conductive material carbon, titanium nitride, antimony tin oxide (ATO) method to improve the a Li4Ti5O12 rate performance of the negative electrode material. The experimental results show that: the coated carbon, titanium nitride, antimony tin oxide (ATO), to improve the initial discharge capacity of the material; discharging magnification 5C, the discharge capacity after 10 cycles were 127.3 mAh/g.111.0 mAh / g, 88.1 mAh / g, compared to pure phase Li4Ti5O12 material 5C rate discharge capacity 76.0mAh / g, and rate performance has been improved in different degrees, wherein the effect of improving the carbon coating is preferably followed by titanium nitride, ATO The effect is not obvious.
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