li z ni x co y mn 1‑x‑y o 2 Material Compounding Method

Abstract

The invention relates to a compounding method for a LizNixCoyMn (1-x-y) O2 material. The compounding method comprises the following steps of: 1, preparing compact small-grained spherical LizNixCoyMn (1-x-y) O2 powder; 2, preparing compact large-grained spherical LizNixCoyMn (1-x-y) O2 powder; and 3, compounding the two LizNixCoyMn (1-x-y) O2 materials. According to the compounding method provided by the invention, the two LizNixCoyMn (1-x-y) O2 powders with different size distributions and tap densities are compounded and mixed for optimizing the grain size distribution of the material; the large and small particles are tightly matched for solving the problem that the compaction density and energy density are low when a ternary material is independently utilized; and the mass density is higher than 600 mAh / cm<3>, specific surface area is smaller than 0.23g / m<2>, safety and cyclicity of the material are improved. Besides, the compounding method has a simple process and low cost, is very suitable for industrial operation, and has an extensive development prospect.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery cathode materials, in particular to a Li Z Ni X co Y mn 1-X-Y o 2 Material compounding method. Background technique [0002] Due to its high energy density and high compaction density, lithium cobalt oxide has always been the mainstream cathode material for lithium-ion batteries. After about 30 years of development, the performance of lithium cobalt oxide has reached its limit. Today, with the sudden emergence of new materials with high energy density, the energy density of lithium cobalt oxide has been difficult to meet the energy density requirements of current 3C products; in terms of compaction density, lithium cobalt oxide has good electrode processing performance, and the shape control has tended to Perfect, its compaction density has reached its own limit at present, and there is almost no room for further improvement, and lithium cobalt oxide still has unsatisfactory safet...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problems of poor overcharge resistance and safety of lithium cobalt oxide and high material cost due to the dependence on too much precious metal cobalt, people have developed a ternary material Li Z Ni X co Y mn 1-X-Y o 2 , the material has the advantages of high specific capacity, good cycle performance, good safety and low price

However, the secondary agglomerates of the small particles of the material are easily broken during rolling. Even if the primary particles of the agglomerates are enlarged, it is difficult to ensure that the material remains unbroken under high pressure. The contact between the junction agent and the conductive agent is not tight, which will cause polarization and deteriorate the performance of the electrode, so this material is not suitable for use alone

At present, most battery manufacturers use this ternary material in combination with lithium cobalt oxide. Since there is a large particle of single crystal lithium cobalt oxide to provide support for the ternary material, it ensures good electrode processing performance of the mixed positive electrode material. Mixed positive electrode materials The compaction density of lithium cobalt oxide is slightly lower than that of lithium cobalt oxide, and the energy density is slightly higher than that of lithium cobalt oxide. However, the mixed positive electrode material still has problems such as multiple sintering, complicated process, high energy consumption, and poor matching of mixed powder.

[0004] After searching, it was found that the Chinese invention patent with the application number 200910110132.9, the publication number CN101707252A, and the name "polycrystalline cobalt-nickel-manganese ternary positive electrode material and its preparation method, and secondary lithium-ion battery" produced polycrystalline cobalt through high-temperature fusion Nickel-manganese ternary cathode material, which grows different cathode materials into a whole, combines the advantages of mixed materials, shows good electrochemical performance, and the compacted density can reach 3.9g / cm 3 Above, the energy density of a single pole piece is greater than 570mAh / cm 3 (Polar sheet energy density mAh / cm 3 =Initial discharge capacity mAh / g X compacted density g / cm 3 ); but this material still has not got rid of the technical state of co-firing with lithium cobaltate, and the safety of the material has not improved, although it is about 570mAh / cm2 with lithium cobaltate 3 The unit energy density is equivalent, but due to multiple sintering and mixing, and the use of more cobalt, its technical advantages are weakened

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