Polycrystal high-nickel positive electrode material used for lithium ion battery and preparation method for polycrystal high-nickel positive electrode material

Abstract

Disclosed is a polycrystal high-nickel positive electrode material used for a lithium ion battery. The polycrystal high-nickel positive electrode material comprises a base material with a layered structure and a coating layer which is arranged outside the base material and has a spinel structure; the general formula of the base material is LiNi<1-x-y>Co<x>M<y>O<2>, wherein M is at least one kind of Mn and Al; the coating layer is lithium manganese oxide; the mass percentage of the total impurity lithium on the surface of the base material is less than 0.085% based on the total mass percentage of the base material; the preparation method for the positive electrode material comprises the following steps of weighing Ni<1-x-y>Co<x>M<y>(OH)<2>, and mixing with a lithium source, then carrying out thermal treatment, cooling, crushing and sieving to obtain the base material; measuring the content of the residual impurity Li<2>CO<3> and LiOH on the surface of the base material, adding into the metal Mn compound according to the measurement result, and carrying out low-temperature thermal treatment in an oxygen atmosphere to obtain the polycrystal high-nickel positive electrode material used for the lithium ion battery. The polycrystal high-nickel positive electrode material provided by the invention has the advantages of low material alkalinity, low inflatable degree, excellent processing property and cycling performance, and the like.

Description

technical field [0001] The invention relates to a positive electrode material for a lithium battery and a preparation method thereof, in particular to a high-nickel positive electrode material for a lithium secondary battery and a preparation method thereof. Background technique [0002] High-nickel cathode materials have the advantages of high theoretical discharge specific capacity, good rate performance, low cost, and high safety, and are suitable for use as high-energy cathode materials for electric vehicles (EV), hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles. However, as the proportion of nickel content increases, the content of residual lithium salts on the surface of the material increases, and the degree of mixing of cations in the material increases. As a result, the slurry is prone to "jelly" phenomenon in the battery production process, and the storage performance Poor battery gas, poor cycle performance and other issues have seriously affect...

AI Technical Summary

Problems solved by technology

However, as the proportion of nickel content increases, the content of residual lithium salts on the surface of the material increases, and the degree of mixing of cations in the material increases. As a result, the slurry is prone to "jelly" phenomenon in the battery production process, and the storage performance Poor battery gas, poor cycle performance and other issues have seriously affected the commercialization of high-nickel materials

[0003] CN201110162133 Chinese patent discloses a liquid-phase precipitation method to prepare the core, the middle and the surface composite multi-phase manganese-based material xLi 2 MnO 3 ·LiNi 0.3 mn 0.7 o 2 y(MO), its content is highly controllable, the core composition is uniform, and it has the characteristics of high safety and long cycle life, but the oxide is an inert substance, which is not conducive to the migration of lithium ions and electrons, and is easy to cause the initial discharge capacity decline

[0004] Chinese Patent No. CN200910109331 and Chinese Patent No. CN201210359842 disclose that the lithium ion conductor compound coats the lithium battery ternary material matrix, and improves the processability and electrochemical performance by reducing the lithium impurities, but the lithium ion conductor compound does not exert capacity, which will reduce the first discharge Capacity and first charge and discharge efficiency

Images