Study On Coating Modification Of TiO 2 / Sub - Nanosheets And The Negative Performance Of Lithium Ion Batteries

The two lithium ion battery for energy density and power density with high green power energy has become one of the most promising candidate. But the traditional lithium ion batteries tend to poor rate performance of graphite as the electrode material, simply can not meet the demand, equipment and its surface in low voltage or charge/discharge occurs when the lithium dendrite, and short circuited or even explosion hazards, the focus of the current study is to develop a lithium capacity high magnification and cycle performance excellent new materials to replace graphite electrodes.TiO₂ has the advantages of simple preparation, rich source, low price, no pollution, so it is often used as a semiconductor material for the scholars to study in different fields. But the current electronic conductivity and lithium ion TiO₂ dispersion rate is very low, will lead to its widespread application in the lithium ion battery. In order to overcome this defect, this paper using the hydrothermal method. The prepared TiO₂ nanosheets coated by carbon and metal oxide will be a high-performance anode material for Li-ion batteries.（1） Different Crystal structure’s TiO₂ nanosheets were prepared by three-step hydrothermal method. The microstructure and morphology of the as-prepared TiO₂ nanosheets were studied in terms of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, X-ray photoelectron spectroscopy （XPS） and Transmission electron microscope （TEM）. Furthermore, the electrochemical performances of the as-prepared TiO₂ nanosheets were investigated in terms of galvanostatic charge/discharge and alternative current （AC） impedance spectroscope. The results showed that anatase and rutile mixed phases TiO₂ nanosheets electrode delivered an initial discharge capacity of about 206 mAh/g, higher than 173 mAh/g of the bare anatase phase TiO₂ nanosheets electrode. Meanwhile, anatase and rutile mixed phases TiO₂ nanosheets electrode displayed better cycle stabilities and rate performances than bare anatase phase nanosheets TiO₂ electrode.（2） C@TiO₂、MnO₂@C@TiO₂ and Fe2O3@C@TiO₂ nanosheets were prepared by hydrothermal method with coat or load. The microstructure and morphology of the as-prepared three kinds of nanosheets were studied in terms of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, X-ray photoelectron spectroscopy （XPS） and Transmission electron microscope （TEM）. Furthermore, the electrochemical performances of the as-prepared three kinds of nanosheets were investigated in terms of galvanostatic charge/discharge and alternative current （AC） impedance spectroscope. The results showed that Fe2O3@C@TiO₂ nanosheets have the best performance as anode material for Li-ion batteries in the three kinds of nanosheets.Its electrode delivered an initial discharge capacity of about 891 mAh/g, delivered an initial charge capacity of about 729 mAh/g, impedance is 38 Ω. Meanwhile, Fe2O3@C@TiO₂ nanosheets electrode displayed better cycle stabilities and rate performances than another two nanosheets electrode.