In-situ doping and coating upgrading regeneration method for waste ternary positive electrode material

Abstract

The invention discloses an in-situ doping, coating, upgrading and regenerating method for a waste ternary positive electrode material, and belongs to the technical field of battery recovery. The method comprises the following steps: calcining the waste ternary positive electrode material in an oxidizing atmosphere to obtain a pure-phase intermediate; ball-milling and mixing the pure-phase intermediate with a lithium source and M oxides (aluminum oxide, silicon dioxide and the like) to form a mixture; according to the method, in-situ doping, coating, upgrading and regeneration of the waste ternary positive electrode material are realized through a pyrogenic process, and the obtained regenerated ternary positive electrode material has excellent electrochemical performance and cycling stability.

Description

Technical Field

[0001] This invention relates to a method for regenerating waste ternary cathode materials, and more particularly to a method for upgrading and regenerating waste ternary cathode materials to prepare doped and coated ternary cathode materials, belonging to the field of waste battery recycling technology. Background Technology

[0002] Ternary cathode materials, as one of the key cathode materials in lithium-ion battery systems, exhibit high theoretical specific capacity and energy density, and have been widely used in daily life. However, due to the limited cycle life (8-10 years) of ternary cathode materials, large-scale retirement of these materials has been implemented in recent years. Waste ternary cathode materials contain abundant elements such as Ni, Co, Mn, and Li, making them economically valuable. Currently, the processing of ternary cathode materials mainly involves element extraction and direct regeneration. Element extraction primarily involves dissociating the ternary cathode material structure using pyrometallurgical or hydrometallurgical methods to obtain a solution rich in metal elements, followed by extraction and purification processes. While this process is relatively mature, it suffers from high energy consumption and heavy pollution. Direct regeneration, as a novel recycling technology, is based on the failed crystalline phase structure and uses structural restoration to restore the material's structure and performance. This process boasts high element utilization, low energy consumption, and minimal pollution. However, many current ternary cathode materials are produced using processes from over 10 years ago, and even if their performance is fully restored, it is difficult to achieve the performance indicators of ternary materials produced using current technologies. For example, Chinese patent application (publication number: CN112939096A) discloses a direct repair method for ternary cathode materials from spent lithium-ion batteries. Specifically, the ternary powder to be repaired is mixed evenly with supplementary elements and then directly subjected to high-temperature calcination. This reduces Li-Ni mixing caused by cycling and repairs the damaged layered crystal structure. The repaired ternary cathode material exhibits high discharge specific capacity and good cycle performance. While this method can repair ternary cathode materials to their initial level, its performance is not upgraded or regenerated. Summary of the Invention

[0003] To address the technical deficiencies of existing technologies, the present invention aims to provide a method for in-situ doping and coating upgrade and regeneration of waste ternary cathode materials. This method achieves in-situ doping and coating upgrade and regeneration of waste ternary cathode materials through pyrometallurgical processes, and the resulting regenerated ternary cathode materials exhibit excellent electrochemical performance and cycle stability.

[0004] To achieve the above-mentioned technical objectives, the present invention provides a method for in-situ doping and coating upgrade and regeneration of waste ternary cathode materials, which includes the following steps: S1: Place the waste ternary cathode material in an oxidizing atmosphere for calcination. A pure-phase intermediate was obtained;

[0005] S2: The pure phase intermediate is ball-milled and mixed with a lithium source and M oxide to form a mixture; the M oxide includes at least one of aluminum oxide, silicon dioxide, molybdenum oxide, tungsten oxide, vanadium pentoxide, and boron oxide;

[0006] S3: Calcination of the mixture under an oxidizing atmosphere. This yields recycled ternary cathode materials.

[0007] The key to the technical solution of this invention lies in the following: the waste ternary cathode material is first oxidized and calcined. During the oxidation and calcination process, not only can the residual conductive carbon, organic fluorine impurities and other impurities in the waste ternary cathode material be removed, but the crystal reconstruction of the ternary cathode material can also be achieved through high temperature to obtain a single pure phase intermediate. The intermediate is further regenerated through high temperature. The key to the high temperature regeneration process is the in-situ introduction of M oxide, which is an acidic or amphoteric oxide, as a doping and coating source. The M oxide (MO) and Li2O (lithium source decomposition product) can be used to form a new phase Li-MO compound that is uniformly coated on the surface of the ternary cathode material under high temperature. Since the Li-MO compound coating layer is rich in lithium, it can act as a conductor of lithium ions and provide a transport path for the rapid migration of lithium elements at the surface interface. In particular, this invention makes full use of the physicochemical defects on the surface of waste ternary cathode materials to form physicochemical bonds with Li-MO compounds. While repairing the surface defects of waste ternary cathode materials, it can improve the bonding stability of the coating layer and form a uniform coating layer, effectively improving the cycle stability of the recycled ternary cathode material.

[0008] As a preferred embodiment, the calcination The conditions are: temperature 350℃~800℃, time 0.5h~8h. If the calcination temperature is too low or the calcination time is too short, the residual conductive carbon, organic fluorine impurities, and other impurities in the waste ternary cathode material cannot be effectively removed, resulting in a high content of residual impurities in the regenerated ternary cathode material. The presence of these impurities will also affect the formation of the subsequent Li-MO compound coating layer, ultimately leading to poor electrochemical performance of the regenerated ternary cathode material. If the calcination temperature is too high or the calcination time is too long, premature repair of the crystal phase will occur, making it difficult for impurities introduced from the oxides to enter the bulk structure of the ternary cathode material. Calcination The conditions are further optimized as follows: temperature 450℃~600℃, time 2h~6h. Calcination. It can be carried out in an air atmosphere or an oxygen atmosphere.

[0009] As a preferred embodiment, the lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium nitrate. The preferred lithium source readily decomposes into active Li₂O at high temperatures, and Li₂O can form a new phase, Li-MO compound, with M oxide.

[0010] As a preferred embodiment, the amount of lithium source used is 1.0 to 1.3 times the molar lithium deficiency of the waste ternary cathode material. The molar lithium deficiency of the waste ternary cathode material is obtained directly by ICP testing. If the amount of lithium source added is too low relative to the waste ternary cathode material, lithium source loss will occur during high-temperature calcination, resulting in insufficient lithium content and numerous vacancy defects in the recycled material. If the amount of lithium source added is too high relative to the waste ternary cathode material, it will result in a large amount of residual lithium in the recycled material, affecting the electrochemical performance of the recycled material, especially causing severe side reactions. The amount of lithium source used is further preferably 1.05 to 1.2 times the molar lithium deficiency of the waste ternary cathode material.

[0011] As a preferred embodiment, the amount of M oxide used is 0.5-10% of the mass of the waste ternary cathode material. If the amount of M oxide added is too small relative to the waste ternary cathode material, the M oxide will mainly enter the defects of the waste ternary cathode material, acting as a dopant and making it difficult to form a coating layer. If the amount of M oxide added is too large relative to the waste ternary cathode material, some of the M oxide will not be able to react effectively with the lithium source, resulting in the formation of M metal oxide impurities in the recycled ternary cathode material, affecting the subsequent electrochemical performance. The amount of M oxide used is further preferably 1.0-5.0% of the mass of the waste ternary cathode material.

[0012] As a preferred embodiment, the calcination The process includes two sintering stages. The first sintering stage is performed at a temperature of 400℃ to 800℃ for 0.5 to 8.0 hours; the second sintering stage is performed at a temperature of 700℃ to 1000℃ for 5 to 24 hours. As a preferred embodiment, the first sintering stage is performed at a temperature of 450℃ to 650℃ for 2.0 to 6.0 hours; the second sintering stage is performed at a temperature of 800℃ to 950℃ for 6 to 12 hours.

[0013] calcination The sintering process is carried out in an air or oxygen atmosphere, with oxygen providing a sufficient oxidation environment, making it the preferred atmosphere. The first stage of sintering primarily aims to decompose the lithium salt to form active Li₂O, promoting the formation of Li-MO compounds. If the sintering temperature is too low or the sintering time is too short, it is detrimental to the formation of Li-MO compounds, making it difficult to form a uniform coating layer. If the sintering temperature is too high or the sintering time is too long, it can lead to localized agglomeration of the coating layer, resulting in uneven and imperfect coating. The second stage of sintering primarily aims to repair defects in the ternary cathode material. If the sintering temperature is too low or the sintering time is too short, it can lead to incomplete crystal phase repair in the recycled material, resulting in numerous defect sites. If the sintering temperature is too high or the time is too long, it can cause the collapse of the layered structure inside the ternary cathode material, leading to poor electrochemical performance.

[0014] The waste ternary cathode material of this invention is obtained from decommissioned ternary electrode sheets provided by a company. Waste ternary phosphate powder is obtained through separation using existing conventional techniques.

[0015] The ball milling and other processes involved in this invention are conventional operating procedures in the prior art, and their purpose is to ensure that different components are mixed evenly.

[0016] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects:

[0017] This invention achieves in-situ doping and coating upgrade and regeneration of waste ternary cathode materials through a single pyrometallurgical process. The resulting regenerated ternary cathode material has excellent electrochemical performance and cycle stability.

[0018] The method for regenerating waste ternary cathode materials of the present invention is simple, low-cost, and produces no secondary pollution, which is conducive to industrial production. Attached Figure Description

[0019] Figure 1 XRD pattern of the regenerated ternary cathode material in Example 1; from Figure 1 As can be seen, the recycled ternary cathode material exhibits a good crystal structure, and the lithium-nickel mixture is only 3.0%, which is much lower than that of the waste ternary cathode material before repair (8.0%). This indicates that the crystal structure of the recycled ternary cathode material has been effectively repaired. Furthermore, no other impurity peaks were found in the XRD of the recycled material, indicating that the added M metal oxide has been completely combined with the ternary cathode material and is highly uniformly dispersed on the surface or in the bulk structure of the ternary cathode material.

[0020] Figure 2 Transmission electron microscopy of the regenerated ternary cathode material in Example 1; from Figure 2 As can be seen, the surface of the recycled ternary cathode material has a layer of material with a structure different from the bulk phase, which is the formed coating layer structure.

[0021] Figure 3 Cycle stability of the regenerated ternary cathode material in Example 1; from Figure 3 As can be seen, the cycle stability of the regenerated ternary cathode material is such that, after 100 cycles at a current density of 1.0C, the capacity retention rate of the regenerated material is 82.5%. Detailed Implementation

[0022] The following examples are used to illustrate the content of this invention, but are not intended to limit the scope of protection of the claims of this invention.

[0023] Although this specification describes specific embodiments, it does not imply that each embodiment contains only one independent technical solution. This descriptive method is for clarity only, and those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. Such other embodiments are also within the protection scope of this invention.

[0024] Comparative Example 1:

[0025] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0026] S2. 100g of waste ternary cathode material A and 0.149mol of lithium hydroxide are ball-milled to obtain mixture B;

[0027] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0028] Example 1:

[0029] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0030] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0031] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0032] Example 2:

[0033] S1. Waste lithium-ion battery ternary 622 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.141 mol.

[0034] S2. 100g of waste ternary cathode material A is ball-milled with 0.141 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B.

[0035] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0036] Example 3:

[0037] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 350℃ for 0.5 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0038] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0039] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0040] Example 4:

[0041] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 800℃ for 8 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0042] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0043] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0044] Example 5:

[0045] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0046] S2. 100g of waste ternary cathode material A is ball-milled with 0.074 mol of lithium carbonate and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0047] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0048] Example 6:

[0049] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0050] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% aluminum oxide (based on the amount of ternary cathode material added) to obtain mixture B.

[0051] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0052] Example 7:

[0053] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0054] S2. 100g of waste ternary cathode material A is ball-milled with 0.135 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0055] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0056] Example 8:

[0057] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0058] S2. 100g of waste ternary cathode material A is ball-milled with 0.176 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B.

[0059] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0060] Example 9:

[0061] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0062] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 0.5% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0063] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an air environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0064] Example 10:

[0065] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0066] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 10.0% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0067] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0068] Example 11:

[0069] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0070] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0071] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an air environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0072] Example 12:

[0073] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0074] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0075] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 400℃ for 0.5h and the second stage sintering conditions are 900℃ for 8h. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0076] Example 13:

[0077] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0078] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0079] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 800℃ for 8 hours and the second stage sintering conditions are 900℃ for 8 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0080] Example 14:

[0081] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0082] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0083] S3. The slurry mixture B is placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 700℃ for 5 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0084] Example 15:

[0085] S1. Waste lithium-ion battery ternary 811 series materials were placed in air and calcined at 500℃ for 3 hours to remove residual acetylene black, organic fluorine impurities, etc., to obtain relatively pure waste ternary cathode material A. ICP testing showed that the lithium deficiency content per 100g of waste ternary material was 0.135 mol.

[0086] S2. 100g of waste ternary cathode material A is ball-milled with 0.149 mol of lithium hydroxide and 2% by mass of silicon dioxide (based on the amount of ternary cathode material added) to obtain mixture B;

[0087] S3 and slurry mixture B are placed in a tube furnace and subjected to high-temperature two-stage sintering in an oxygen environment. The first stage sintering conditions are 500℃ for 5 hours and the second stage sintering conditions are 1000℃ for 24 hours. After natural cooling, the resulting material is an upgraded regenerated material with doping and coating synergy.

[0088] The electrochemical performance test results of the regenerated ternary lithium batteries in Comparative Example 1 and Examples 1-15 are shown in Table 1:

[0089] 1) Sample preparation

[0090] Regenerated lithium manganese iron phosphate and acetylene black were mixed and added to a pre-prepared PVDF gel (dissolved in NMP). The mass ratio of regenerated material, acetylene black, and PVDF was 8 / 1 / 1. The resulting slurry was coated onto aluminum foil and then dried in a vacuum oven at 100°C for 12 hours. The resulting electrode was cut into small round pieces using a slicing machine to become the obtained positive electrode material. The aluminum foil was loaded with 2 mg of C14. -2 Active substances.

[0091] The obtained positive electrode sheet, electrolyte, lithium metal, battery casing, separator, etc., are placed in an argon-filled glove box for battery assembly. After sealing, the resulting battery is an assembled coin cell.

[0092] Note: All embodiments use the above-described electrode material preparation method.

[0093] 2) Testing Methods

[0094] After the obtained button cells were left to stand for 8 hours, they were placed on the blue electrode test channel for electrochemical performance testing, with the voltage range set to 2.8~4.3 V. The obtained data are directly displayed on the blue electrode tester and can be directly used.

[0095]

Claims

1. A method for in-situ doping and coating upgrade and regeneration of waste ternary cathode materials, characterized in that: Includes the following steps: S1: Place the waste ternary cathode material in an oxidizing atmosphere for calcination. A pure-phase intermediate was obtained; S2: The pure phase intermediate is ball-milled and mixed with the lithium source and M oxide to form a mixture; The M oxide includes at least one of aluminum oxide, silicon dioxide, molybdenum oxide, tungsten oxide, and vanadium pentoxide; S3: Calcination of the mixture under an oxidizing atmosphere. This yields recycled ternary cathode materials.

2. The method for in-situ doping and coating upgrade and regeneration of waste ternary cathode materials according to claim 1, characterized in that: The calcination The conditions are: temperature 350℃~800℃, time 0.5h~8h.

3. The method for in-situ doping and coating upgrading and regeneration of waste ternary cathode materials according to claim 1, characterized in that: The lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium nitrate.

4. A method for in-situ doping and coating upgrading and regeneration of waste ternary cathode materials according to claim 1 or 3, characterized in that: The amount of lithium source used is 1.0 to 1.3 times the molar amount of lithium deficiency in the waste ternary cathode material.

5. The method for in-situ doping and coating upgrading and regeneration of waste ternary cathode materials according to claim 1, characterized in that: The amount of the M oxide used is 0.5 to 10% of the mass of the waste ternary cathode material.

6. The method for in-situ doping and coating upgrade regeneration of waste ternary cathode materials according to claim 1, characterized in that: The calcination The process includes two sintering stages. The conditions for the first sintering stage are: temperature of 400℃~800℃ and time of 0.5h~8.0h; the conditions for the second sintering stage are: temperature of 700℃~1000℃ and time of 5h~24h.

7. The method for in-situ doping and coating upgrading and regeneration of waste ternary cathode materials according to claim 6, characterized in that: The conditions for the first stage of sintering are: temperature 450℃~650℃, time 2.0h~6.0h; the conditions for the second stage of sintering are: temperature 800℃~950℃, time 6h~12h.

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