High-compaction and high-energy-density ultrahigh-nickel ternary positive electrode material

Abstract

The invention discloses a high-compaction and high-energy-density ultrahigh-nickel ternary positive electrode material, the general formula of the positive electrode material is LinNiaCobMncMdNeO2, and the positive electrode material comprises a polycrystalline material and a single crystal material; the polycrystalline material accounts for 45-90 parts by weight, and the single crystal material accounts for 10-55 parts by weight; the D50 of the polycrystalline material and the D50 of the single crystal material meet the relational expression: K=(D1-D2) / D2, wherein K is more than or equal to 0 and less than or equal to 4. The ternary positive electrode material has the beneficial effects that: the polycrystalline material and the single crystal material with different particle sizes are mixed according to a proper ratio, so that the single crystal material can be fully filled in gaps of the polycrystalline material, a washing link is canceled in the preparation process, a dry process is adopted, a coating agent reacts with free lithium on the surface of the material to generate a fast ion conductor to coat the surface of the material, so that the specific discharge capacity is improved, the production process is simplified, the cost is reduced, and meanwhile, the cycle and DCR performance is improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to an ultra-high nickel ternary positive electrode material with high compaction and high energy density. Background technique [0002] Lithium-ion batteries are widely used in digital products and power markets such as smartphones and notebook computers due to their high operating voltage, high energy density and long life. In recent years, with the continuous development of power lithium-ion batteries, consumers have put forward higher requirements for the energy density, cycle performance and safety performance of power batteries. At present, the positive electrode material studied has a layered structure mainly LiCo0 2 ,LiNiO 2 ,LiMnO 2 , LiMn with spinel structure 2 o 4 , LiFePO with olivine structure 4 wait. Among them, layered ternary LiNi x co y mn z o 2 Due to its high energy density, cathode materials have attracted the attention of the market. T...

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Problems solved by technology

By mixing polycrystalline and single crystal products of positive electrode materials with a Ni content of more than 92%, it is possible to achieve higher energy density while achieving high compaction density. Currently, there is no patent in this regard;

[0005] 2. At present, due to the high Ni content of high-nickel single crystal materials, there is a large amount of residual lithium on the surface of the material, which needs to be removed by water washing, but water washing will damage the surface of the material, resulting in a decline in cycle performance, and a rapid increase in DCR. It is difficult to achieve mass production. In the patent CN111630002B, the single crystal material undergoes a wet grinding step, that is, there is a water washing step. The patent CN110010889A also undergoes a water washing step. The process is complicated and not suitable for implementation;

[0006] 3. For the mixed positive electrode materials with different particle sizes, there is currently a lack of research on the relationship between their particle sizes and the performance of the mixed materials. Patent CN111630002B puts forward requirements for the span of particles, but does not explore the particle size relationship between polycrystalline and single crystal For the impact on material properties, the patent CN109888235A mixed single crystal and polycrystalline materials with different particle sizes, but also did not explore the effect of the particle size relationship between the two on material properties

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