Study On Preparation And Modification Of Li₄Ti₅O₁₂ And Transitional Metal Oxide Energy Storage Material

With the popularization of new energy vehicles, lithium-ion battery has become the first choice for motivation equipment of hybrid vehicles.Well, energy storage materials of lithium titanate battery is Li4Ti5O12 which is so called "zero strain" electrode materials. It possess many advantages, such as superior cycling performance, fast charging capability, long service life and clean, which makes it popular in the market. Besides, as potential energy electrode materials, the transition metal oxides are equiped with high theoretical capacity, and also attract many scientists’ attention.On the basis of summarizing the research progress of lithium ion battery anode materials, this paper introduces some new synthesis technologies of new energy storage materials.Such as, Li4Ti5O12, TiO2, NiO and their modification materials. Moreover, a variety of electrochemical test methods, SEM, EDS, TEM, XRD and other modern testing technology are used together on the lithium titanate and transition metal oxides tests.A series of Li-Ti-O compounds are prepared by atmospheric-pressure hydrolysis ion exchange synthesis method. The amount of Li+ in precursor directly affects compound composition, structure and morphology of Li-Ti-O.Synthetic Li4Ti5O12, Li4Ti5O12-Li2TiO3 and Li4Ti5O12-Ti O2 are equiped with porous sword shape morphology.Especially, the porous sword shape Li4Ti5O12 materials show high capacity, excellent performance and cycle performance.The synthetic Ti O2 prepared by atmospheric-pressure hydrolysis ion exchange method has flower microstructure. The diameter of each flower microstructure unit is between 0.5um and 2um. Each flower has many whiskers which diameter is about 20-100 nm.The methods for synthesis of porous microstructure is beneficial for electrolyte to soak into active material. Its nano-sized whisker can wake the "size effect" and the diffusion resistance of lithium ion to improve lithium ionic conductivity.Particularly, the amorphous samples show the best electrochemical performance.It delivers an initial discharge capacity of 350 mAh g-1. After 50 times cycle,the amorphous samples have 207.7 mAh g-1 the reversible capacity at 0.1C.The 3D porous structure NiO nanofibers anode materials with electrochemical activity are synthesized by sol-gel and electrospinning method. The initial charge and discharge specific capacity of NiO nanofibers active materials obtained under different sintering temperature are higher than the NiO theory capacity(718 mAh/g).But their irreversible capacity loss is larger for the first time. Electrochemical tests show that the PVP-Ni(Ac)2 sintered at 500 ?C reveals the optimal electrocheimcal performance. After 50 cycles, the discharge specific capacity still remains 334 mAh g-1 at 0.1C.In this paper, nickel oxide and lithium titanate are composited to modify anode materials, obtaining good effect. The specific capacity, cycle and ratio performance of substrate materials are improved.The experiment show that LTONiO(5%) sample in four groups shows the best cycle and rate performance. After 308 cycles, the discharge specific capacity still remains 187.6 mAh g-1 at 20 C. Moreover, LTONiO(10%) sample delivers the discharge capacity of 153.8 mAh g-1 under similar confidion. They all show better performance than pure LTO which is 120.9 mAh g-1.The lithium titanate and nickel oxide composite will have good application prospect.