Synthesis And Charaeterization Of Anode Composites Lithium Titanate For Lithiumion Battery

As a high performance chemical power source, lithium-ion battery has an important position among small electrical equipment. Meanwhile, it is the most promising power supply for electric vehicles (EV) and hybrid electric vehicles (HEV). Recently, with the rapid development of EV and HEV, lithium-ion batteries are put forward higher requirements in higher power density, energy density, long cycling stability and safety. So, it is necessary to do the further research on electrode materials. This research focused on the anode material of lithium-ion battery lithium titanate. The Li4Ti5O12anode material has a good charge and discharge platform, the structural stability in the charge and discharge process, good reversibility and cycling stability. However, its poor electrical conductivity and small ion diffusion coefficient result in high polarization and low capacity during high-magnification charge and discharge process. Therefore, some modified researches of LTO were carried out in the research against these shortcomings.Acetylene black and the binary conductive agent of acetylene black and multi-walled carbon nanotube were introduced into LTO precursor utilizing the solid phase method of ball milling, which effectively reduced the particle size and made the particle distribution more uniform. A better ratio capability and cycle reversibility showed in electrochemical tests. Especially in composite material LTO/AB/MWCNTs, an embedded structure was formed by MWCNTs and LTO, and the synergistic effect of this embedded structure and the homogeneously-dispersed particles AB around LTO effectively increased the conductivity dimension of the material. The material has excellent electrochemical performance and good electrical conductivity compared with pure LTO and LTO/AB with the discharge capacity of116.3mAh/g at20C. The capacity maintained at161.1mAh/g after1000times of cycles at2C, only a4.8%loss of the capacity.LTO/C nano-composite material was prepared by sol-gel method and sol-hydrothermal method. The structure system not only improved the conductivity of the material, but also shortened the diffusion path of charges and effectively changed the electrochemical properties of LTO. From the electrochemical tests on LTO/C composite synthesized by sol-gel method, the capacity remained at138.7mAh/g and122.1mAh/g after500cycles at10C and20C, respectively. The specific capacity of micron-ball LTO/C nano-composite synthesized by sol-hydrothermal method was127.8mAh/g at20C. The capacity at5C was152.4mAh/g, and the specific capacity was147.2mAh/g after1000cycles, the material also showed excellent electrochemical performance.LTO was composited with2D-structure conductive agent graphene for the preparation of nano-structured composite material. The initial doff-lithium capacity was139.1mAh/g at5C. The specific capacity was133.4mAh/g after500cycles, and the specific capacity was115.6mAh/g after1000cycles; the product from the hydrothermal reaction of graphene oxide and ethylenediamine was composited with LTO to generate composite material LTO/NC/GNS which improved the dynamic performance of electrode material and showed better electrochemical performance than LTO/GNS. The initial lithium-intercalation capacity was144.9mAh/g. The capacity after500cycles was140mAh/g, and after1000cycles the capacity was120.5mAh/g.