| In recent years layer rich lithium manganese base positive materials Li[Li1/3-2x/3NixMn2/3-x/3]O2(x=0.275,0.35) with its high discharge specific capacity good structural stability and lower cost has becoming one of the hot topics in the study of material. But some of the material structure doping components influence on the performance of the remains to be further investigation. This thesis research Li[Li1/3-2x/3NixMn2/3-x/3]O2(x=0.275,0.35) of the preparation, through the optimized synthesis process and magnesium oxide, oxidation silicon, calcium oxide and modification of doping anion method, with the hope of enhance the comprehensive performance of materials.This paper, by orthogonal experiment roasting temperature and time of heat treatment, and draw the conclusion that the most appropriate roasting system:the three sections of roasting way, of which20℃to500℃of warming rate is2.5℃/min insulation time for four hours,500℃to750℃to900℃temperature period for the heating rate5℃/min, holding time ratio for4:16. The synthesis of Li-ion battery anode materials [Li0.15Ni0.275Mno0575]02has the following the electrochemical properties:25℃, in constant temperature under4.6V into4.2V circulation,1C rate to charge and discharge conditions, materials for the first time specific capacity discharge146.6mAh/g,100cycles specific capacity discharge for143mAh/g, capacity to keep rate was97.54%, but the first charge and discharge irreversible capacity is higher. Li-ion battery anode materials [Li0.15Ni0.275Mn0.575]02first discharge specific capacity144.1mAh/g,250cycles specific capacity damping for122mAh/g.This paper studies, the doping magnesium oxide, lithium manganese base layer rich positive influence of material[Li0.15Ni0.275Mn0.575]02and Li [Li0.1Ni0.35Mn0.55]O2. The results showed that2%MgO materials doped in Li [Li0.15Ni0.275Mn0.575]O2samples show good electrochemical performance, in constant temperature25℃1C rate,4.6V forming and2.5V-4.2V cycle for the first time specific discharge capacity143.9mAh/g, after200times cycles keep142.0mAh/g, material attenuation to minimum and the stability of the circulation by the best. Doping2%MgO and2%LiF sample after200cycles specific discharge capacity can slightly increase. Doped with1%MgO materials Li1Li0.1Ni0.35Mn0.55]O2samples for the first time specific discharge capacity146.8mAh/g after500cycles keep125.5mAh/g, material attenuation to minimum and the stability of the circulation by the best. The material Li[Lio.i5Nio.275Mno.575]02doped after CaO electrochemical performance fell sharply.This paper studies the doping oxidation silicon to lithium manganese base layer rich positive influence of materials [Li0.15Ni0.275Mn0.575]O2and Li [Li0.1Ni0.35Mn0.55]O2. The results showed that the materials Li[Li0.15Ni0.275Mn0.575]O2doped1%SiO2have certain ascend the structure stability, in constant temperature25℃1C rate,4.6V forming and2.5V-4.2V cycle for the first time specific discharge capacity146.7mAh/g, after200times cycles keep142.0mAh/g, material attenuation to minimum and the stability of the circulation by the best. When doping amount1%SiO2materials Li[Li0.1Ni0.35Mn0.55]O2can improve the rate of performance and cycle material performance, the very piece of thermal stability also to have certain ascend. |
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