High-nickel lithium ion battery positive electrode material, preparation method thereof and lithium ion battery

Abstract

The invention provides a positive electrode material of a high-nickel lithium ion battery, a preparation method thereof and a lithium ion battery, wherein, the method comprises the following steps: (1) a metal oxide is coated on the surface of the electrode material by a mixing or spray drying method to obtain a coated electrode material; The mass ratio of metal oxide to electrode material is (0.1-2): 100; (2) adding the coating electrode material obtained in the step (1) into water for stirring, wherein the mass ratio of the coating electrode material to water is (0.5-10): 1; Dehydration anddrying. The invention also provides a high-nickel lithium ion battery positive electrode material prepared by the method and a lithium ion battery using the positive electrode material. The method ofthe invention not only effectively reduces the residual alkali on the surface of the layered high-nickel positive electrode material, but also minimizes the destruction of the surface structure and the cycle performance of the material during the alkali reduction process. The layered high nickel positive electrode material prepared by the method has low residual alkali content, high reversible capacity and excellent cycling performance.

Description

technical field [0001] The invention belongs to the technical field of electrode material preparation and lithium-ion batteries, and in particular relates to a high-nickel lithium-ion battery cathode material, a preparation method thereof, and a lithium-ion battery. technical background [0002] Lithium-ion batteries have the advantages of high energy density, high discharge platform, long cycle life, and no memory effect. They have been widely used in mobile phones, cameras, notebook computers and other fields. At the same time, they have also begun to be used in power batteries such as electric bicycles and electric vehicles. Lithium cobalt oxide cathode material is the earliest cathode material to be commercialized, but cobalt resources are limited, expensive, and polluted, which limits its further development. Layered high-nickel composite oxide cathode material LiNi x m 1-x o 2 (where 0.6≤x≤1, M is one or more of Co, Mn, Al, Mg, Ti, V, Cr, Zr, Nb, Ga, Sr) because of ...

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Problems solved by technology

[0005] The above method has obvious defects: (1) Although water washing effectively reduces the pH value (alkali content) of the positive electrode material, the aqueous solution directly contacts the surface of the material to form Li 2 O, in the process of material storage, it will accelerate the reaction of material and moisture, and re-form Li 2 CO 3 and LiOH, so that the pH value increases, therefore, the alkali-reducing effect of the washed sample will be invalid after storage for a certain period of time; (2) the direct contact of the aqueous solution with the surface of the material will accelerate the continuous diffusion of the Li atoms inside the particles to the outside of the particles surface, while the Ni inside the material 3+ Spontaneous transformation into Ni 2+ , leading to a sharp decline in the cycle performance of the washed sample

[0007] However, the above method also has the following defects: among the selected oxyacids, phosphoric acid is relatively strong, and when it reacts with the free lithium compound on the surface, it will accelerate the continuous diffusion of Li atoms inside the particles to the surface of the particles; silicic acid, boric acid 1. The acidity of titanic acid is weak, and the reactivity with lithium salt is very weak. The alkali reduction mainly relies on the water in the solvent to directly contact the surface of the material to take away the lithium salt, which will also lead to a significant decline in the reversible capacity and cycle performance of the treated material.

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