Titania Hollow Micro-nanostructure: Synthesis And Applications In Lithium Ion Batteries

Because of so many advantages such as high energy density, long cycle life, no pollutions, lithium-ion batteries have important applications in portable electric devices and power batteries. The evolution of anode materials is relatively mature. Nowdays commercial anode materials are mostly intercalated-lithium carbon materials such as graphite carbon materials and intermediate phase carbon microspheres, etc. But the carbon materials also have their disadvantages. As anode materials of power battery, the first principle is low fading after long time and fast charging-discharging cycles. So long cycle life, the stability and safety in high rates are essential for anode material. In the anode materials, titanium based (mainly including TiO2and Li4Ti5O12) materials exhibit extremely high cycle life, low price, excellent safety and rates performance. The followings are main contents and results:1. Mesocrystal NH4TiOF3nanobricks were obtained with hydrothermal method by adding NH4F and Ti(OC4H9)4in HAc solution. Treating with H3BO3solution, they transformed to hollow TiO2nanobrick structure with ordered arranging nanothorns. The experimental results demonstrate this structure is helpful to improve the photocatalytic activity in degrading organic dyes. That’s because the hollow nanobrick has the hierarchical structure, large specific surface and high crystallinity. In lithium-ion batteries measurement, the hollow TiO2nanobrick exhibited high first discharge capacity.2. TiO2hollow nanospheres were obtained successfully by bubble template. Ti(SO4)2were used as titanium source, H2O2were used as bubble generating material to produce O2, and NH4Cl were used as catalytic in the decomposing of H2O2. And in the lithium-ion batteries measurement, the hollow nanospheres showed high first discharge capacity and high coulombic efficiency.3. Some kinds of titanium coordination microspheres assembled by ultrathin nanosheets were synthesized by adding some additives in HAc-TBT system. Through post thermal treating, the products turned into pure anatase TiO2with the microstructure unchanged. Also, the products exhibited excellent cycle capacity and rate performance. The superior property is related to their unique hierarchical micro-nanostructure.