CN-121983696-A - Controllable doping regeneration method for waste ternary material

CN121983696ACN 121983696 ACN121983696 ACN 121983696ACN-121983696-A

Abstract

The invention discloses a doping regeneration method of waste ternary materials, and belongs to the technical field of lithium battery material regeneration. The invention relates to a doping regeneration method of a waste ternary material, which comprises the steps of crushing a waste ternary positive plate, sorting to obtain a current collector and ternary powder respectively, adding magnesium oxide into the ternary powder, mixing, carrying out mechanical fusion to obtain a ternary material containing a magnesium oxide coating layer, carrying out first-stage sintering, adding lithium salt into the sintered ternary material, and carrying out second-stage sintering. According to the invention, the interface of the failure material is doped by utilizing a controllable and quantitative co-doping mode of Mg 2+ /F ‑ , and a doping proportion formula and a sintering condition formula of magnesium are established according to the Ni content, so that the repair and regeneration of the medium-high nickel ternary material are completed. Wherein, the introduced Mg 2+ /F ‑ element forms a co-doped structure at the interface, a more stable interface structure is newly built, and the problems of poor solid phase repair and regeneration performance and low quality of the high-nickel ternary material are solved.

Inventors

LIU KELU
WANG TAO
YANG LEI
LAI WENFENG
Yan Ruguo
Hua Runjie

Assignees

江西天奇金泰阁钴业有限公司

Dates

Publication Date: 20260505
Application Date: 20260129

Claims (10)

1. The doping regeneration method of the waste ternary material is characterized by comprising the following steps of: s1, crushing the waste ternary positive plates, and then sorting to obtain a positive current collector and ternary powder respectively; S2, adding magnesium oxide into the ternary powder material in the step S1, mixing, and then mechanically fusing to obtain a ternary material containing a magnesium oxide coating layer; s3, performing first-stage sintering on the ternary material of the S2 coating layer containing the magnesium oxide to obtain a sintered ternary material; and S4, adding lithium salt into the sintered ternary material, mixing, and performing second-stage sintering to obtain the regenerated ternary material.
2. A doping regeneration method according to claim 1, wherein in S1, the ternary material of the ternary lithium battery comprises at least one of a middle-nickel ternary material and a high-nickel ternary material.
3. A doping regeneration method according to claim 1, wherein in S2, the average particle diameter of the magnesium oxide is 15 to 25nm, and/or the specific surface area of the magnesium oxide is 60 to 150m 2 /g.
4. A doping regeneration method according to any one of claims 1 to 3, wherein the addition amount of the magnesium oxide in the ternary material is calculated according to formula (1); Formula (1); In the formula (1), M Mg represents the molar mass of magnesium element, M MgO represents the molar mass of magnesium oxide, and the doping amount of Mg element refers to the mass fraction of the magnesium element doped in the regenerated ternary material in unit weight percent; the numerical value of the doping amount of the Mg element is calculated according to the formula (2); The numerical value of the doping amount of Mg element=0.05N-0.15 formula (2); Wherein, the Formula (3); Wherein n Ni is the molar quantity of Ni element in the ternary powder material, and n Ni +n Co+ n Mn is the total molar quantity of Ni+Co+Mn in the ternary material.
5. The doping regeneration method according to claim 1, wherein in S2, the time of the mechanical fusion is 15 to 35min.
6. The doping regeneration method according to claim 1, wherein in S3, the first stage sintering is performed at a rate of 2 to 3 ℃ per minute, and the temperature is raised to 400 to 450 ℃ and maintained for 2 to 3 hours.
7. A doping regeneration method according to claim 1, wherein in S4, the lithium salt comprises at least one of lithium hydroxide and lithium carbonate.
8. A doping regeneration method according to claim 1 or 7, wherein the addition amount of the lithium salt is 0.15 to 0.25wt% of the total amount of the ternary material after sintering in step S3.
9. The doping regeneration method according to claim 1, wherein in S4, the second stage sintering is performed by heating to a temperature T at 4-8 ℃ per min and then maintaining the temperature; the unit of the temperature T is the temperature, and the T is calculated according to the formula (4); T=876 to 17×n formula (4); Wherein N is calculated by the formula (3); Formula (3); Wherein n Ni is the molar quantity of Ni element, n Ni +n Co+ n Mn is the total molar quantity of Ni+Co+Mn; The heat preservation time is H, and the unit is H; Wherein h=10.5 0.5N formula (5); Wherein N is calculated by the formula (3); The sintering atmosphere is an oxygen atmosphere.
10. A ternary material prepared by the doping regeneration method of any one of claims 1-9.

Description

Controllable doping regeneration method for waste ternary material Technical Field The invention relates to the technical field of recycling of waste lithium batteries, in particular to a controllable doping regeneration method of waste ternary materials. Background With the continuous expansion of the demand of high-energy density power lithium batteries, the application volume of ternary materials is gradually increased. The ternary battery production and manufacturing process can generate a large amount of leftover pole piece materials, and due to the instability of the chemical properties of the ternary materials, the leftover materials react with moisture and carbon dioxide in the air to fail in the storage and transportation processes, oxygen loss and lithium precipitation occur in the failure process, and rock salt phase impurities (mainly NiO) are formed on the surface. For the middle and high nickel ternary material, the problem of element re-uniform distribution is difficult to solve by the current solid phase repair mode of the waste ternary material, and the problem is that the valence of nickel in the middle and high nickel ternary material is partially +3, and the conversion energy barrier of Ni 2+→Ni3+ in the solid phase sintering process is higher, so that the mixed phase NiO cannot completely convert Ni 3+ in the sintering process, and unconverted Ni 2+ can enter the Li + position more easily, so that Li +/Ni2+ mixed discharge is formed. On the other hand, the recycled material contains a large amount of F impurities, the part of F impurities are difficult to remove, and during the sintering process, a large amount of F elements are doped into the material (the F introduction amount reaches 0.5-0.8 wt%) to further inhibit the oxidation of Ni 2+ and enter a metal layer, so that part of Ni 2+ enters Li + to form more Li +/Ni2+ mixed rows, and the mixed row structure can lead to the capacity reduction of the material and the reduction of the cycle life. Elemental doping is an effective means of improving the performance of ternary materials, and at present, doping of elements such as aluminum, titanium, zirconium, magnesium, lanthanum, fluorine and the like has been demonstrated to improve the stability of ternary materials. Wherein, magnesium doping can change the valence state of transition metal, and new electron holes are manufactured, thereby improving the conductivity of the material, and meanwhile, fluorine doping can strengthen the bond energy of metal-oxygen bonds and reduce the surface side reaction activity. In the patent CN 114314691A, CN 118431605A, CN 112993260B, CN 113611857B, mg element is doped into a metal layer in situ by means of spray pyrolysis and hydrothermal precipitation, F is doped into an oxygen position, so that the Mg-F doped ternary material is prepared, and the chemical property of the ternary material is improved. Mg, F doping has been shown to be effective for materials. However, for the recycled waste ternary material, how to shield the side effect of fluorine element, and quantitatively and controllably form fluorine and magnesium co-doping, and simultaneously, the repair and regeneration of the middle-high nickel ternary material are completed, which is an unsolved technical problem in the field of repair and regeneration at present. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a controllable doping regeneration method of waste ternary materials. According to the method, the interface of the failure material is doped in a controllable and quantitative co-doping mode of Mg 2+/F-, and a magnesium doping proportion formula and a relation between sintering temperature and sintering time are established according to the Ni content in the ternary material to be regenerated, so that the repair and regeneration of the medium-high nickel ternary material are completed. The Mg 2+/F- is introduced to form a co-doped structure at the interface of the ternary material, a more stable interface structure is newly built, the problems of poor solid-phase repair regeneration performance and low quality of the high-nickel ternary material are solved, and the battery prepared from the regenerated ternary material has excellent cycle stability. The technical scheme of the invention is as follows: the invention provides a doping regeneration method of waste ternary materials, which comprises the following steps: s1, crushing the waste ternary positive plates, and then sorting to obtain a positive current collector and ternary powder respectively; S2, adding magnesium oxide into the ternary powder material in the step S1, mixing, and then mechanically fusing to obtain a ternary material containing a magnesium oxide coating layer; s3, performing first-stage sintering on the ternary material of the S2 coating layer containing the magnesium oxide to obtain a sintered ternary material; and S4, adding lithium salt into the sintered ternary mate