Nickel-cobalt-manganese multi-doped lithium ion battery cathode material and preparation method thereof

Abstract

The invention discloses a nickel-cobalt-manganese multi-doped lithium ion battery cathode material with high compacted density and a preparation method thereof, belonging to the technical field of energy materials. The preparation method of the battery cathode material comprises the following steps: preparing a nickel-cobalt-manganese multi-doped intermediate by a coprecipitation method or a chemical synthesis method; mixing the multi-doped intermediate with lithium salts; after pretreatment, adding polyvinyl alcohol to the obtained mixture; uniformly mixing the polyvinyl alcohol and the mixture and then pressing the mixture into a cake; roasting the cake at 800-950 DEG C; taking the roasted cake out and carrying out cooling, pulverization and 400 meshes of sieving on the cake; then roasting obtained powder at 700-800 DEG C, taking the powder out and carrying out cooling, pulverization and sieving on the powder to obtain the battery cathode material. Granules of the battery cathode material are non-agglomerated single-crystal grains with a grain diameter of 0.6-30 microns, a chemical formula of LiNixCoyMnzM[(1-x-y-z)]O2, a degree of compaction of 3.5-3.7g / cm<3> and a primary discharge capacity of 150-165mAh / g, thus the battery cathode material has good cycle performance and higher safety performance.

Description

technical field [0001] The invention discloses a nickel-cobalt-manganese multiple-doped lithium-ion battery cathode material and a preparation method thereof, belonging to the technical field of energy materials. Background technique [0002] At present, the positive electrode material of lithium-ion batteries used in mobile phones and notebook computers is mostly lithium cobalt oxide. Lithium cobaltate has an initial discharge capacity of 140-145mAh / g and has good cycle performance. Since 1992, it has been widely used as the cathode material of lithium-ion batteries. After years of continuous improvement, the compacted density of lithium cobalt oxide cathode material has reached 3.6-3.8g / cm 3 , which can meet the requirements of laptop batteries for the capacity per unit volume of positive electrode materials. However, due to the shortage of cobalt resources, lithium cobalt oxide materials are expensive, and there are still defects such as difficulty in further increasing...

AI Technical Summary

Problems solved by technology

However, the preparation process of nickel-cobalt-lithium-manganese-manganese multi-element positive electrode material whose shape is polycrystalline particles is more complicated, although the prepared complex-crystalline particle nickel-cobalt-lithium manganese oxide multi-element positive electrode material has a higher tap density (tap density can reach 2.4g / cm), its compaction density can reach 3.2~3.4g / cm 3 , but it is difficult to further improve; and because the polycrystalline particles formed by the combination of multiple particles, the particle size is difficult to be uniform, and the particle size distribution is wide. In the process of preparing battery pole pieces, some fine particles are easy to fall off from the surface of the polycrystalline particles , leading to poor stability of the product; and the spherical polycrystalline particles have greater hygroscopicity, and are easy to absorb moisture when exposed to the air, which affects the performance of the product

Therefore, the nickel-cobalt-manganese multi-element cathode material of polycrystalline particles is difficult to be practically applied in high-end lithium-ion battery products (such as laptop batteries, etc.)

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