Preparation And Properties Of Li-ion Battery Anode Materials Li₄Ti₅O₁₂

As the lithium ion batteries are widely used in the widespread portable electrical devices, and almost all the commercial anode materials are carbon materials. However, the irreversible capacity of carbon is considerable, and there are also potential dangers of carbon anode. Spinel type lithium titanate (Li4Ti5O12) is the most attractive candidate for anode of lithium ion batteries. When used as anode, the structural change of lithium titanate after Li+insertion is negligible, because the lattice parameters of this change are less than0.5%. Comparing with carbon anode, the Li4Ti5O12possess a very long life, a very flat charge-discharge voltage platform and also a high safety.Pure lithium titanate and pilot-scale production were synthesized by solid state composition in this thesis. And the key equipments and processing parameters in large scale production were defined by the pilot study of Li4Ti5O12material through solid state. And sorts of properties of the Li4Ti5O12were tested. Concretely, the temperature and time of composition, the parameters of ball milling and different lithium sources of the pure lithium titanate were studied in detail. The crystal structure of Li4Ti5O12was described by XRD and the morphology was studied via SEM, then the size distribution of Li4Ti5O12particle was analyzed by a laser particle size analyzer. Furthermore, the electrochemical performances were researched in detail by the battery test system. The results were as follows:1.The results of the electrochemical test of the pure lithium titanate showed that the influences of the temperature and time of the sintering were notable. And the product which presintered at750℃for6h and then sintered at850℃for15h possessed the best performance. A higher or lower temperature would lead to impure products and disappointed performances. And also the time a played very important roles in the ball milling. And the product which ball milled with absolute ethyl alcohol as dispersant for6h did the best. 2. The key equipments and processing parameters in large scale production were defined by the pilot study of L14Ti5O12material through the solid state approach. And the former material’s grain size is normal distribution. It is the most important that all the performances of this material meet the requirements of merchantable Li-ion batteries. The feasibility of this new method to synthesize Li4Ti5O12material was proved and the technology parameters and indexes also were fixed. A general method with low cost and high efficiency has been provided to produce cathode materials in large scale, which has great significance theoretically and practically.