| Lithium ion secondary battery is an excellent chemical power supply. Its rapid development in last decades was mainly attributed to the improvement and progress of cathode material. Up till now, LiCoO2 served as cathode material, with layer structure like α-NaFeO2, has being already extensively used in small sized commercial lithium ion battery. Although the cyclic property, and discharge capacity at multiple ratio current were good for LiCoO2, but the insecurity under over charge condition restrict its application in large sized lithium batteries, except of the limiting factors of resources and prize related with cobalt. LiNiO2 with layer structure was believed to be an attractive potential cathode material, due to its low prize, high specific capacity and environment benign. But it is difficult to produce stoichiometric LiNiO2 with pure phase, and its crystal structure is instable during charge-discharge cycle that leading to the loss of capacity gradually, all these obstruct the practical application of LiNiO2. In order to modify the crystal structure stability of LiNiO2 and improve its electrochemical property, an useful method commonly used in the field of researching LiNiO2 based cathode material was partially substituting the Ni atom in LiNiO2 by variety elements to form solid solution of multi-components.The main point of this thesis was to investigate the technology for preparing the cathode material with layer structure for lithium ion battery, such as LiNi0.8-xCo0.2AlxO2 based on LiNixCo1-xO2 and LiNi1/3Co1/3Mn1/3O2 based on LiNi0.5Mn0.5O2, and to study the relation between the technique parameters and the performance feature of the yields.1. Research on the material based on LiNixCo1-xO2Different methods for preparing LiNi0.8-xCo0.2AlxO2 and the performance feature of the target products were compared, from the views of crystal structure, thermal stability and electrochemical property, by means of X-ray diffraction (XRD), thermal gravimetric analysis (TGA), cyclic voltammogram (CVA) and charge-discharge of simulated cell. The results are showed as follow.1.1 LiNiO2 can't be prepared by a low temperature solid state reaction from trivalence nickelates and lithium hydroxide. When Co is doped, LiNi0.8Co0.2O2 , with LiNiO2 structure, is synthesized in air. When Co and Al are doped at the same time, LiNi0.7Co0.2Al0.1O2 with LiNiO2 structure is easily received by two-step calcination in air (the 1 st step:600℃ 6h;the 2nd step: 750℃10h). LiNi0.7Co0.2Al0.1O2 synthesized by sol-gel method has large particle size and small agglomerates.1.2 LiNi0.7Co0.2Al0.1O2 with well-ordered hexagonal structure is synthesized by two-step calcination in air from different nickel resources. With the same 1 st step calcination condition, the 2 nd step calcination temperature is 700,750 and 800℃ for β -NiOOH, Ni2O3 and Ni(OH)2 respectively . In addition, the cell volumes fortrivalence nicklates resources are smaller than that for Ni(OH)2, and I(003)/I(104) is larger than that for Ni(OH)2. All indicates that LiNi0.7Co0.2Al0.1O2 from trivalence nickelates resources has a better crystal and better layered structure.
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