| Due to the same lattice structure and the adjacent in the periodic table, LiCoO2, LiNiO2, LiMnO2has a good Structural complementarity and can be mixed together in various proportation.As a cathode material for LIB (Lithium ion battery), layered three element material provides attracting advantages Including larger reversible capacity, better cycle performance, safety and cheap cost.In this paper, Ni0.5Co0.2Mn0.3(OH)2and Li2CO3are chosen as raw materials. To pursue an industrial production of high performance LiNi0.5Co0.2Mn0.3O2, improved the methods of mixing and modified sintering process are studied. The main contents are as follows:(1) Selection and development of equipments. The precursors mixing is one of the key steps of this industrial route. It is very important to mix micron Ni0.5Co0.2Mn0.3(OH)2, Li2CO3and bond them together without destroying their morphology. According to the requirements of mixing, the traditional double screw cone blender and oblique grinding mixer were abandoned, while a high precision efficient mixer was used. The high speed and homogenous mixed can be obtained by using this new mixer which confirms that the precursors can go through a random3D ball milling process. Calcination is another crucial step. The traditional mesh belt furnace and push plate furnace are abandoned, while developed a sealed rotary roaster, which can let the material claimed uniformly and fully contract with oxygen to make sure it’s excellent performance.(2) Presintering time, calcinations temperature, calcinations time, calcinations atmosphere and the proportion of Li have been studied. The effects of different process parameters on the physical and chemical properties of material are investigated on the basis of XRD, SEM, EIS and charge-discharge test. The best equipment parameters are listed as following:The calcinations atmosphere is O2; the proportion of Li is1.1:1.Two sinter step; In1st step, the sinter time is7hours and sinter temperature is600℃, In2nd step, the sinter time is12hours and sinter temperature is900℃.The material synthesized by optimum technological parameters has a high degree of crystalline. It’s first discharge capacity is199mAh/g in the voltage range of2.5V-4.6V.(3) The Precursors from three different manufacturers are tested and compared. Firstly, particle size distribution and SEM of the Precursors are analyzed, secondly. The materials synthesized by different Precursors with best optimum technological parameters are characterized. The analysis results show that the performance of the material is greatly impacted by its morphology and particle size distribution of precursor.The product particle size distribution was determined by its precursor’s particle size. This is an important factor which can influence its tap density. The morphology of the precursor is also a direct impact on the morphology of the final material. A smooth spherical which has some micropores in the density surface is the ideal morphology for precursor. The smooth and density spherical precursor ensure the material has the same ideal morphology. It is beneficial to enhance the tap density of the material. The microporous in the surface facilitate the reaction between precursor and Li2CO3. |
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