Spherical layered nickel-cobalt-manganese oxide lithium-ion battery cathode material

Abstract

The invention relates to spherical lamellar cathode material for a lithium nickel manganese cobalt oxide lithium ion battery. The cathode material contains LiZNixCoyMn1-X-YO2, and is characterized in that the LiZNixCoyMn1-X-YO2 is compounded by small dense spherical particles and big dense spherical particles of LiZNixCoyMn1-X-YO2. By compounding two types of LiZNixCoyMn1-X-YO2 with different particle size distributions and tap densities, the invention optimizes the particle distribution of the cathode material, and the big particles and the small particles are tightly bound, so the problems of low compaction density and energy density of ternary material when the material is used alone are solved. The spherical lamellar cathode material reaches the mass density of 600mAh / cm<3> and the specific surface area of the cathode material is less than 0.25m<2> / g. The safety property and the cycle performance of the cathode material are improved while the electrochemical activity of the cathode material remains unchanged, and the cathode material is simple in production process and low in cost. Therefore, the spherical lamellar cathode material is suitable for industrial production and has a broad development prospect.

Description

technical field [0001] The invention belongs to the technical field of positive electrode materials for lithium ion batteries, in particular to a spherical layered nickel cobalt manganese oxide lithium lithium ion battery positive electrode material. 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 improvem...

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 caused by 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 compaction 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 its technical advantages are weakened due to multiple sintering and mixing, as well as the use of more cobalt

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