Modifying method of ternary anode material

Abstract

The invention discloses a modifying method of a ternary anode material. The modifying method is characterized by comprising the following steps: (1), adding the ternary anode material LiNixCoyMnzO2 into an acetic acid solution, stirring for 20 min-40 min, and then washing and drying, wherein x is not less than 0.3 and not more than 1, y is not less than 0 and not more than 0.5, z is not less than 0 and not more than 0.5, and (x+y+z) is equal to 1; (2), adding a lanthanum element into the dried ternary anode material, wherein the lanthanum element is metal lanthanum or a compound of metal lanthanum of which the mass is 0.5%-2% of the mass of the ternary anode material; then adding distilled water, uniformly stirring to form slurry; and (3), directly heating the slurry material in an air atmosphere to 600-900 DEG C according to a heating rate step by step, sintering for 2-8 hours, cooling to the room temperature, grinding and sieving to obtain the lanthanum oxide-coated ternary anode material.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for modifying a ternary positive electrode material. Background technique [0002] Due to the advantages of small size, light weight, long cycle life, large specific energy and no memory effect, lithium-ion batteries have been widely used in portable electronic products and new energy vehicles. The positive electrode material is one of the core parts of lithium-ion batteries. , which greatly affects the performance of lithium-ion batteries. [0003] At present, among the cathode materials of lithium-ion batteries, the most studied is LiCoO 2 , LiNiO 2 and LiMn 2 o 4 . LiCoO 2 It is the earliest lithium-ion battery cathode material to realize industrialization and commercial application, but cobalt is a rare resource, expensive, and has certain pollution to the environment; LiNiO 2 Although the theoretical specific capacity is high, the synthesis is d...

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Problems solved by technology

[0004] Although the lithium-nickel-cobalt-manganese composite oxide ternary cathode material has many advantages mentioned above, due to its Ni 2+ with Li + The ionic radius is relatively close, and it is easy to appear Ni 2+ with Li + The mixing phenomenon makes the material prone to lithium precipitation in the air, and forms Li on the surface of the ternary material. 2 CO 3 Lithium compounds such as LiOH make the PH value of the ternary material higher, resulting in poor electrochemical performance of the material

If the pH value is too high, on the one hand, it is not conducive to the dispersion and stirring of the slurry; on the other hand, if the pH value is too high, the material will react with aluminum foil to form Al(OH) 3 , producing flocculent precipitates, for Li + At the same time, the released gas will cause the battery to bulge during the charging and discharging process, especially at high temperature, which will have a serious impact on the capacity, cycle life, and rate performance of the battery. influences

At present, the traditional coating generally adopts the solid phase coating method, and the coating cannot be uniformly coated on the surface of the material, resulting in the erosion of fluoride and transition metals on the surface of some positive active particles of the material during the charge and discharge process. The dissolution of ions causes the surface layered structure to collapse and cycle performance to deteriorate

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