A method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction

Abstract

The present invention relates to the technical field of lithium batteries, and specifically relates to a method for regenerating waste lithium nickel cobalt manganese oxide cathode materials assisted by surface structure reconstruction. The regeneration method includes: mixing the lithium nickel cobalt manganese oxide cathode material powder after alkali soaking, drying, and calcination treatment with a surface precursor substance and a chelating agent in deionized water, heating to evaporate to dryness, calcining, mixing the obtained product with a lithium salt, and further calcining to obtain a regenerated lithium nickel cobalt manganese oxide cathode material with surface structure reconstruction. The surface structure reconstruction-assisted direct regeneration process provided by the present invention overcomes the difficulty in lithium supplementation kinetics, breaks through the limitations of the existing direct solid-phase sintering technology, and the electrochemical performance of the regenerated NCM cathode material product is superior to that of the NCM cathode material regenerated by the existing direct solid-phase sintering technology, reaching and being superior to the performance of commercial NCM cathode materials. In addition, it has significant fast charging performance under high-rate conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling and recycling of waste lithium-ion power batteries, and particularly relates to a method for regenerating waste lithium nickel cobalt manganese oxide cathode materials assisted by surface structure reconstruction. Background Art

[0002] Nowadays, lithium-ion batteries are widely used in new energy vehicles, energy storage and other fields. Due to its high energy density, excellent cycle performance and thermal stability, lithium nickel cobalt manganese oxide (NCM) materials are widely used as the cathode of lithium-ion batteries. However, the limited life cycle of lithium-ion batteries makes more and more lithium-ion batteries reach the end of their life and be scrapped, and these scrapped batteries urgently need effective recycling and reuse. The existing recycling and reuse methods mainly include pyrometallurgy, hydrometallurgy and direct recycling. Among them, pyrometallurgy and hydrometallurgy have the advantages of mature technology, but are accompanied by the risks of high energy consumption and environmental pollution. Direct recycling is a technology based on non-destructive and in-situ repair, and has been widely studied by scientists due to its simple steps and high recycling efficiency.

[0003] The existing direct recycling methods mainly include molten salt, hydrothermal and solid-phase sintering methods, etc. Among them, the solid-phase sintering method is to achieve lithium supplementation and structure repair by high-temperature sintering of lithium salts and waste NCM materials according to a certain stoichiometric ratio. Due to its similarity to the production process of the original industrial cathode materials, the solid-phase sintering method has the potential for large-scale industrial application. However, the failure structure on the surface of waste NCM materials significantly increases the difficulty of lithium supplementation kinetics, hinders structure repair, and results in poor direct regeneration effect of the materials.

[0004] There is no report on the surface structure reconstruction-assisted regeneration of waste NCM materials in the market at present. Using surface structure reconstruction to assist the direct regeneration of waste NCM materials has considerable foresight and will bring huge economic and environmental benefits. Summary of the Invention

[0005] Based on this, the present invention provides a method for regenerating waste lithium nickel cobalt manganese oxide cathode materials assisted by surface structure reconstruction, a regenerated lithium nickel cobalt manganese oxide cathode material and its application. The present invention can better recycle waste NCM materials through direct regeneration, breaking through the limitations of the existing direct solid-phase sintering process.

[0006] To achieve the above object, on the one hand, the present invention provides a method for regenerating waste lithium nickel cobalt manganese oxide cathode materials assisted by surface structure reconstruction, comprising the following steps:

[0007] S1. Immerse the waste lithium nickel cobalt manganese oxide cathode material powder in an alkaline solution, then filter, dry and calcine to obtain the pre-treated lithium nickel cobalt manganese oxide cathode material powder;

[0008] S2. Add the mixture of the pretreated lithium nickel cobalt manganese oxide cathode material powder, the surface precursor substance, and the chelating agent to deionized water, mix well, heat and evaporate to dryness to obtain a dry gel, and then calcine the dry gel to obtain the lithium nickel cobalt manganese oxide cathode material powder with a reconstructed surface structure;

[0009] Among them, the surface precursor substance is one or more of a manganese-based cathode (such as LiMn₂O₄), a boron-containing cathode (such as LiCo 0.5 Mn 0.5 BO₃), and its function is to form an effective lithium ion rapid transport channel on the material surface; the chelating agent is an organic acid with a coupling effect and no other impurities introduced;

[0010] S3. Mix the lithium nickel cobalt manganese oxide cathode material powder with the surface structure reconstructed with a lithium salt and perform a calcination treatment to obtain a regenerated lithium nickel cobalt manganese oxide cathode material with a reconstructed surface structure.

[0011] The inventor's research found that the treatment in step S2 can reconstruct the surface structure of the failed NCM material. Specifically, using the chelation of the above organic acid with transition metals (Ni, Co, Mn) to reconstruct the surface structure of the material, a lithium ion rapid transport channel is constructed for the material, significantly improving the lithiation effect and structure repair effect in the solid-phase sintering process, thus breaking through the limitations of the existing direct solid-phase sintering process.

[0012] The present invention first directly regenerates and repairs waste NCM materials through surface structure reconstruction assistance, and can directly recycle retired NCM batteries on the market. The process flow is short, the operation is simple, the pollution can be greatly reduced, the production cost can be saved, and the regenerated NCM cathode material has excellent performance, especially the fast charging ability at high rates.

[0013] As a further preferred technical solution of the present invention, in step S1, the waste lithium nickel cobalt manganese oxide cathode material powder is LiNi with a layered structure x Co y Mn z O₂, x + y + z = 1, which includes but is not limited to a mixture of one or more of LCO, LNO, NCM111, NCM523, NCM622, NCM8 series, and NCM9 series.

[0014] As a further preferred technical solution of the present invention, in step S1: the alkaline solution is sodium hydroxide, potassium hydroxide, or lithium hydroxide, with a concentration of 0.001 - 5 mol / L; and / or, the waste lithium nickel cobalt manganese oxide cathode material powder is soaked in the alkaline solution, and stirring is carried out at normal temperature and pressure, and the stirring time is 2 - 12 h.

[0015] As a further preferred technical solution of the present invention, in step S1: the temperature of the drying treatment is 50 - 80 °C, and the time is 1 - 5 h; and / or, the temperature of the calcination treatment is 300 - 500 °C, and the time is 1 - 4 h.

[0016] As a further preferred technical solution of the present invention, in step S2, the addition amount of the surface precursor substance is 1 - 5% of the mass of the pre-treated lithium nickel cobalt manganese oxide cathode material powder, and the mass ratio of the pre-treated lithium nickel cobalt manganese oxide cathode material powder to the addition amount of deionized water is 1 - 5 g / L.

[0017] As a further preferred technical solution of the present invention, in step S2, the chelating agent is citric acid or oxalic acid. Further, since the dosage of the chelating agent is related to the number of functional groups, the addition amount of citric acid is 10 - 20% of the mass of the pre-treated lithium nickel cobalt manganese oxide cathode material powder, and the addition amount of oxalic acid is 15 - 30% of the mass of the pre-treated lithium nickel cobalt manganese oxide cathode material powder.

[0018] As a further preferred technical solution of the present invention, in step S2: the temperature of the heating treatment is 60 - 125 °C, and the heating method is water bath, oil bath or silicone bath; and / or, the temperature of the calcination treatment is 150 - 400 °C.

[0019] As a further preferred technical solution of the present invention, in step S3: the lithium salt is one or more of lithium hydroxide, lithium carbonate, lithium acetate, and lithium nitrate; and / or, the temperature of the calcination treatment is 800 - 1000 °C, and the calcination atmosphere is an oxidizing atmosphere containing oxygen (such as oxygen or air).

[0020] According to another aspect of the present invention, the present invention also provides a regenerated lithium nickel cobalt manganese oxide cathode material prepared by the above method.

[0021] According to still another aspect of the present invention, the present invention also provides an application of the regenerated lithium nickel cobalt manganese oxide cathode material in a lithium nickel cobalt manganese oxide battery.

[0022] Compared with the existing direct solid-phase sintering technology, the present invention achieves the following technical effects:

[0023] (1) The process of surface structure reconstruction-assisted direct regeneration provided by the present invention performs surface structure reconstruction on the waste NCM cathode material, reconstructs a fast lithium replenishment channel, and promotes subsequent structure repair, enabling efficient direct regeneration of the waste NCM cathode material;

[0024] (2) The surface structure reconstruction-assisted direct regeneration process provided by the present invention overcomes the difficulties in lithium supplementation kinetics, breaks through the limitations of the existing direct solid-phase sintering technology. The electrochemical performance of the regenerated NCM cathode material product is superior to that of the NCM cathode material regenerated by the existing direct solid-phase sintering technology, reaching and exceeding the performance of commercial NCM cathode materials. In addition, it also has a fast charging performance significantly superior to that of commercial NCM cathode materials.

[0025] (3) The surface structure reconstruction-assisted direct regeneration process provided by the present invention is simple, can be optimized based on the current industrial cathode material production line, can perfectly match the current production equipment and process of cathode materials, and is suitable for large-scale industrial applications.

[0026] (4) The reagents used in the surface structure reconstruction-assisted direct regeneration process provided by the present invention are all green and environmentally friendly reagents that do not cause environmental pollution. The regeneration process is environmentally friendly, and the whole process is green and efficient. Brief Description of the Drawings

[0027] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0028] Figure 1 SEM comparison diagram of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 of the present invention.

[0029] Figure 2 TEM comparison diagram of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 of the present invention.

[0030] Figure 3 XRD comparison diagram of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 of the present invention and NCM after direct solid-phase sintering in Comparative Example 1.

[0031] Figure 4 First-cycle charge-discharge curve diagram of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 of the present invention and NCM after direct solid-phase sintering in Comparative Example 1.

[0032] Figure 5 Cycling performance comparison diagram of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 of the present invention and NCM after direct solid-phase sintering in Comparative Example 1.

[0033] Figure 6 Rate performance comparison diagram of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 of the present invention and NCM after direct solid-phase sintering in Comparative Example 1.

[0034] The realization of the object, functional characteristics and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the drawings. Detailed Description of the Embodiments

[0035] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0036] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which the present invention pertains. The test reagents used in the following embodiments are all conventional biochemical reagents unless otherwise specified; the experimental methods are all conventional methods unless otherwise specified.

[0037] I. The raw material sources of the examples and comparative examples are as follows:

[0038] Unless otherwise specified, the raw material substances used in the examples of the present invention and Comparative Example 1 are all commercially available. Among them, the waste lithium nickel cobalt manganese oxide cathode material is purchased from a battery disassembly manufacturer (Hebei Zhonghua Lithium Battery Technology Co., Ltd.).

[0039] II. The test methods for the various performances of the regenerated lithium nickel cobalt manganese oxide (NCM) cathode material are as follows:

[0040] The regenerated NCM cathode material is configured into a positive electrode slurry, and the mass ratio of the ingredients is regenerated NCM cathode material: conductive agent SP: binder PVDF: NMP = 80:10:10:100. It is coated on aluminum foil, vacuum dried at 80 °C for 12 h, and then cut into electrode sheets. Subsequently, CR2032 coin cells are assembled in a glove box according to the assembly process of coin cells.

[0041] (1) Specific capacity performance test: It is tested through a Neware battery test system. The charging cut-off voltage is 4.3 V, and the lowest discharge cut-off voltage is 2.6 V.

[0042] (2) Long cycle stability test: It is tested through a Neware battery test system, and the set rate is 0.5 C.

[0043] (3) Rate performance test: It is tested through a Neware battery test system, and the tests are carried out at rates of 0.5 C, 1 C, 2 C, 5 C, 10 C, and 15 C respectively, with 5 cycles for each rate.

[0044] Example 1

[0045] A regeneration process for waste lithium nickel cobalt manganese oxide cathode material assisted by surface structure reconstruction, and its specific process method is as follows:

[0046] S1. Immerse the waste NCM cathode material powder in sodium hydroxide solution and stir for 12 h. Then, conduct filtration. After washing the filtrate with deionized water and ethanol, dry it in an oven at 80 °C. Calcinate the dried powder at 400 °C for 2 h to obtain the pre-treated NCM cathode material powder.

[0047] S2. Mix 200 mg of the pre-treated NCM cathode material powder, 6 mg of lithium manganate (LiMn2O4), and 40 mg of citric acid (C6H8O7), dissolve them in 100 ml of deionized water, and heat them in an oil bath at 80 °C until the solvent is completely evaporated to obtain a dry gel. Then, calcinate the dry gel at 300 °C for 2 h to obtain a material powder with a manganese-rich spinel structure on the surface. This manganese-rich spinel structure has high ionic conductivity and electronic conductivity, providing a fast lithium-ion replenishment channel during the regeneration process.

[0048] S3. Mix 100 mg of the material powder with the surface structure reconstructed and 20 mg of lithium hydroxide (LiOH). First, calcinate it at 500 °C for 2 h, and then calcinate it at 900 °C for 4 h. Cool it down to room temperature to obtain the regenerated NCM material with the surface structure reconstructed.

[0049] Figure 1 The SEM images of the waste NCM, the NCM with the surface structure reconstructed, and the NCM regenerated with the assistance of surface structure reconstruction in Example 1 are shown. It can be seen that a manganese-rich spinel structure is chelated on the surface of the waste NCM. This structure opens up a fast lithium replenishment channel inside the material, significantly improving the lithiation and structure repair effects during the subsequent sintering process.

[0050] Figure 2 The TEM images of the waste NCM and the NCM regenerated with the assistance of surface structure reconstruction in Example 1 are shown. It can be seen that there are a large number of disordered lithium-nickel anti-sites inside the waste NCM particles, and there is a rock salt phase on the surface, which hinders the lithium replenishment channel. In contrast, the NCM particles regenerated with the assistance of surface structure reconstruction have a consistent layered structure inside and a manganese-rich spinel structure on the surface. On the one hand, this surface structure effectively improves the lithiation process during the sintering regeneration process, enhances the regeneration repair effect, and overcomes the limitations of the solid-phase sintering method. On the other hand, this structure can also effectively accelerate the lithium-ion deintercalation rate during the charge and discharge process, improving the fast charging performance of the material.

[0051] Figure 3The XRD comparison diagrams of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 are shown. It can be seen that the intensity ratio of (003) to (104) increases from 1.25 to 1.49, indicating that after surface structure reconstruction-assisted regeneration, the structure of the material changes and the degree of lithium-nickel mixing decreases.

[0052] Figure 4 The first charge-discharge curves of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 are shown. It can be seen that the discharge specific capacity increases from 107 mAh g -1 to 152 mAh g -1 , indicating that after surface structure reconstruction-assisted regeneration, the capacity of the material basically recovers to the capacity level before failure.

[0053] Figure 5 The cycle performance comparison diagrams of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 are shown. It can be seen that after 300 cycles, the waste NCM material has basically no capacity, while the regenerated NCM material in Example 1 still has a capacity retention rate of 83%, indicating that after surface structure reconstruction-assisted regeneration, the material exhibits excellent cycle performance.

[0054] Figure 6 The rate performance comparison diagrams of NCM before and after surface structure reconstruction-assisted regeneration in Example 1 are shown. It can be seen that under high rate conditions of 5 C, 10 C, and 15 C, the waste NCM material has basically no capacity, and the regenerated NCM material in Example 1 still exhibits discharge specific capacities of 122 mAh g -1 , 103 mAh g -1 , 87 mAh g -1 , indicating that after surface structure reconstruction, the rich manganese spinel structure on the material surface provides fast lithium ion channels, significantly improving the performance of the regenerated material under high rate conditions.

[0055] Example 2

[0056] S1. Immerse the waste NCM cathode material powder in sodium hydroxide solution and stir for 12 h, then perform filtration treatment. Wash the filtrate with deionized water and ethanol and dry it in a drying oven at 80 °C. Calcinate the dried powder at 400 °C for 2 h to obtain the pre-treated NCM cathode material powder.

[0057] S2. Mix 200 mg of the pre-treated NCM cathode material powder with 6 mg of lithium cobalt manganese boron oxide (LiCo 0.5 Mn 0.5100 mg of boric acid (H₃BO₃) is mixed with 40 mg of citric acid (C₆H₈O₇), dissolved in 100 ml of deionized water, and heated in an oil bath at 80 °C until the solvent is evaporated to obtain a dry gel. Then, the dry gel is calcined at 300 °C for 2 h to obtain a material powder with a boron-rich olivine structure on the surface. This boron-rich olivine structure can provide a one-dimensional directional fast lithium-ion transport channel during the regeneration process.

[0058] S3. Mix 100 mg of the material powder with the surface structure reconstructed with 20 mg of lithium hydroxide (LiOH). First, calcine it at 500 °C for 2 h, and then calcine it at 900 °C for 4 h. Cool it down to room temperature to obtain the regenerated NCM material with the surface structure reconstructed.

[0059] Example 3

[0060] S1. Immerse the waste NCM cathode material powder in a sodium hydroxide solution and stir for 12 h. Then, perform a filtration treatment. Wash the filtrate with deionized water and ethanol and dry it in an oven at 80 °C. Calcinate the dried powder at 400 °C for 2 h to obtain the pre-treated NCM cathode material powder.

[0061] S2. Mix 200 mg of the pre-treated NCM cathode material powder, 6 mg of lithium manganate (LiMn₂O₄), and 60 mg of oxalic acid (H₂C₂O₄), dissolve them in 100 ml of deionized water, and heat in an oil bath at 80 °C until the solvent is evaporated to obtain a dry gel. Then, calcine the dry gel at 300 °C for 2 h to obtain a material powder with a manganese-rich spinel structure on the surface.

[0062] S3. Mix 100 mg of the material powder with the surface structure reconstructed with 20 mg of lithium hydroxide (LiOH). First, calcine it at 500 °C for 2 h, and then calcine it at 900 °C for 4 h. Cool it down to room temperature to obtain the regenerated NCM material with the surface structure reconstructed.

[0063] Comparative Example 1

[0064] S1. Immerse the waste NCM cathode material powder in a sodium hydroxide solution and stir for 12 h. Then, perform a filtration treatment. Wash the filtrate with deionized water and ethanol and dry it in an oven at 80 °C. Calcinate the dried powder at 400 °C for 2 h to obtain the pre-treated NCM cathode material powder;

[0065] S2. Mix 100 mg of the pretreated NCM cathode material powder with 20 mg of lithium hydroxide (LiOH), first calcine it at a temperature of 500 °C for 2 h, then calcine it at a temperature of 900 °C for 4 h, and cool it down to room temperature to obtain the regenerated NCM material by the direct solid-phase sintering method.

[0066] Figure 3 The XRD comparison diagrams of the NCMs in Example 1 and Comparative Example 1 are shown. It can be seen that compared with Comparative Example 1, the intensity ratio of (003) to (104) in Example 1 increased from 1.38 to 1.49, indicating that compared with the direct solid-phase sintering method, after the surface structure reconstruction-assisted regeneration, the degree of lithium-nickel mixing in the structure of the regenerated NCM material is further reduced, and the layered structure is better repaired.

[0067] Figure 4 The first charge-discharge curves of the NCMs in Example 1 and Comparative Example 1 are shown. It can be seen that the discharge specific capacity of the NCM in Comparative Example 1 is 138 mAh g -1 , while the discharge specific capacity of the NCM in Example 1 reaches 152 mAh g -1 , indicating that compared with the direct solid-phase sintering method, after the surface structure reconstruction-assisted regeneration, the capacity of the regenerated NCM material in Example 1 is restored to a better level.

[0068] Figure 5 The cycling performance comparison diagrams of the NCMs in Example 1 and Comparative Example 1 are shown. It can be seen that after 300 cycles, the capacity retention rate of the NCM in Comparative Example 1 is 67%, while the regenerated NCM material in Example 1 still has a capacity retention rate of 83%, indicating that after the surface structure reconstruction-assisted regeneration, the cycling performance of the NCM material has been significantly improved.

[0069] Figure 6 The rate performance comparison diagrams of the NCMs in Example 1 and Comparative Example 1 are shown. It can be seen that under the high rate conditions of 5 C, 10 C, and 15 C, the regenerated NCM material in Comparative Example 1 shows discharge specific capacities of 94 mAh g -1 , 74 mAh g -1 , 54 mAh g -1 , while the regenerated NCM material in Example 1 shows discharge specific capacities of 122 mAh g -1 , 103 mAh g -1 , 87 mAh g -1 , indicating that compared with Comparative Example 1, after the surface structure reconstruction, the fast ion channels provided by the manganese-rich spinel structure on the material surface significantly improve the performance of the regenerated material under high rate conditions.

[0070] The electrochemical properties of the recycled NCM materials provided in Examples 1-3 and Comparative Example 1 were tested and compared with the test results of the waste NCM materials before recycling and the commercial lithium nickel cobalt manganese oxide cathode material CNCM523. The results are shown in Table 1:

[0071] Table 1. Performance test results of examples and comparative examples

[0072]

[0073] The test data in Table 1 regarding the discharge specific capacity under 0.5C charge-discharge conditions and the capacity retention rate after 300 cycles under 0.5C charge-discharge conditions show that by using the surface structure reconstruction-assisted direct regeneration and repair process in Examples 1-3 of the present invention, the electrochemical properties of the obtained recycled NCM materials are significantly improved, capable of meeting and exceeding the commercial use standards, and having obvious advantages compared with Comparative Example 1.

[0074] In summary, the present invention reconstructs the surface structure of waste NCM materials, constructs fast lithium-ion channels on the particle surface, reduces the lithiation energy barrier during the recycling process, realizes uniform lithiation inside the materials, and promotes the subsequent structure repair process. By accelerating the lithiation process and promoting structure repair, the NCM materials regenerated with the assistance of surface structure reconstruction exhibit excellent electrochemical properties, and their discharge specific capacity and cycling performance are superior to those of the materials regenerated by the direct solid-phase sintering method. In addition, the rate performance of the recycled NCM materials is far superior to that of the NCM materials regenerated by the direct solid-phase sintering method. Compared with traditional recycling methods (wet method, pyrometallurgy), the recycling process of the present invention is simple, has little pollution, and can be applied to large-scale industrial applications. Therefore, the surface structure reconstruction-assisted direct recycling process of waste NCM cathode materials of the present invention has obvious advantages compared with Comparative Example 1 and can effectively meet the high standards of customers and the market.

[0075] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The protection scope of the present invention is only defined by the appended claims.

Claims

1. A method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction, characterized in that, It includes the following steps: S1. Immerse the waste lithium nickel cobalt manganese oxide cathode material powder in an alkaline solution, then filter, dry, and calcine it to obtain the pre-treated lithium nickel cobalt manganese oxide cathode material powder; S2. Add the mixture of the pre-treated lithium nickel cobalt manganese oxide cathode material powder, the surface precursor substance, and the chelating agent to deionized water and mix evenly. Heat and evaporate to dryness to obtain a dry gel, and then calcine the dry gel to obtain the lithium nickel cobalt manganese oxide cathode material powder with a reconstructed surface structure. Among them, the surface precursor substance is one or more of a manganese-based cathode and a boron-containing cathode substance; S3. Mix the lithium nickel cobalt manganese oxide cathode material powder with a reconstructed surface structure with a lithium salt and perform a calcination treatment to obtain a regenerated lithium nickel cobalt manganese oxide cathode material with a reconstructed surface structure; In step S2, the chelating agent is citric acid or oxalic acid. The addition amount of citric acid is 10-20% of the mass of the pre-treated lithium nickel cobalt manganese oxide cathode material powder, and the addition amount of oxalic acid is 15-30% of the mass of the pre-treated lithium nickel cobalt manganese oxide cathode material powder. The mass ratio of the pre-treated lithium nickel cobalt manganese oxide cathode material powder to the addition amount of deionized water is 1-5 g / L.

2. The method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction according to claim 1, characterized in that In step S1, the waste lithium nickel cobalt manganese oxide cathode material powder is LiNi with a layered structure x Co y Mn z O2, where x + y + z = 1 3. The method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction according to claim 1, wherein In step S1: The alkaline solution is sodium hydroxide, potassium hydroxide, or lithium hydroxide, and the concentration is 0.001-5 mol / L; and / or, when the waste lithium nickel cobalt manganese oxide cathode material powder is immersed in the alkaline solution, stirring is carried out at normal temperature and pressure, and the stirring time is 2-12 h.

4. The method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction according to claim 1, characterized in that, In step S1: The temperature of the drying treatment is 50-80 °C, and the time is 1-5 h; and / or, the temperature of the calcination treatment is 300-500 °C, and the time is 1-4 h.

5. The method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction according to claim 1, characterized in that, In step S2, the addition amount of the surface precursor substance is 1-5% of the mass of the pre-treated lithium nickel cobalt manganese oxide cathode material powder.

6. The method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction according to claim 1, characterized in that In step S2: The temperature of the heat evaporation to dryness treatment is 60-125 °C; and / or, the temperature of the calcination treatment is 150-400 °C.

7. The method for assisting the regeneration of waste lithium nickel cobalt manganese oxide cathode materials by surface structure reconstruction according to claim 1, characterized in that In step S3: The lithium salt is one or more of lithium hydroxide, lithium carbonate, lithium acetate, and lithium nitrate; and / or, the temperature of the calcination treatment is 800-1000 °C, and the calcination atmosphere is an oxidizing atmosphere containing oxygen.

8. A regenerated lithium nickel cobalt manganese oxide cathode material, characterized in that, It is prepared by using the method described in any one of claims 1-7.

9. An application of the regenerated lithium nickel cobalt manganese oxide cathode material as described in claim 8 in a lithium nickel cobalt manganese oxide battery.

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