Method for realizing single-crystalline regeneration of spent positive electrode material by using vacuum cracking method

Abstract

A method for realizing single-crystalline regeneration of a spent positive electrode material by using a vacuum cracking method. The method comprises: fully mixing a spent polycrystalline ternary positive electrode material of a lithium ion battery with nickel stearate and a lithium salt, melting same, and then calcining same in vacuum so as to obtain a regenerated single-crystalline ternary positive electrode material. The present method not only compensates the loss of lithium of a spent single-crystalline ternary positive electrode material, but also converts insoluble residual Ni on the surface of the single-crystalline material during the "cracking" process of nickel stearate into LiNiO2 capable of providing discharge capacity, thus allowing the regenerated positive electrode material to exhibit more excellent electrochemical properties, and further reducing costs. The method is simple and easy to operate, and has modest requirements on regeneration reaction temperature, and while not needing long-time high-temperature calcination, the method can be used for simultaneously carrying out two processes polycrystalline cracking into single crystalline and lithium replenishment, thus involving low energy consumption, and being easy to popularize.

Description

A method for regenerating waste cathode materials into single crystals by vacuum cracking

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on November 1, 2023, with application number CN202311434349.1 and invention name “A method for single crystal regeneration of waste positive electrode materials using vacuum cracking method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the technical field of recycling waste lithium ion positive electrode materials, and in particular relates to a method for regenerating waste positive electrode materials into single crystals by adopting a vacuum cracking method. Background Art

[0003] Lithium-ion batteries are currently the newest generation of secondary batteries with the highest energy density. They are widely used in mobile communications and digital technology, and more recently, in new energy vehicles and energy storage. Future demand for lithium-ion batteries and materials is difficult to estimate. Ternary layered nickel cobalt manganese oxide (NCM) cathode materials combine the advantages of LiCoO2, LiNiO2, and LiMnO2, three lithium-ion battery cathode materials, with a significant synergistic effect among the three transition metals. With continued support from national policies, ternary cathode materials have become a rapidly growing global market in recent years due to their high energy density, long cycle life, and excellent safety. However, after nearly a thousand cycles of use, they irreversibly reach the end of their lifespan. Decommissioned lithium-ion batteries contain significant amounts of valuable metals such as lithium, nickel, cobalt, and manganese, making them considered "man-made minerals" from which metals can be extracted. Furthermore, my country's lithium resources face challenges in development and purification, resulting in low production and dependence on imports. Nickel ore is low-grade and has high mining costs, making the re-synthesis of ternary cathode materials expensive. If they are not recycled and reused properly, their heavy metal pollution, organic matter and fluorine pollution will make lithium-ion batteries an important source of environmental pollution, which is not conducive to the concept of comprehensive resource utilization and sustainable development. Recycling and reusing retired lithium-ion batteries can not only realize the resource utilization of limited resources and drive the development of a circular economy, but also avoid potential threats to human health and the ecological environment. It has multiple benefits in terms of resources, economy and society. Therefore, the recycling and regeneration of retired lithium-ion batteries has important significance and practical value.

[0004] Ternary cathode materials can be divided into single crystal and polycrystalline types based on their crystal structure. Polycrystalline is composed of many single crystal particles with different orientations. Its entire crystal structure is not permeated by the same lattice. Conventional polycrystalline ternary cathode materials exist in the form of secondary spherical particle agglomerates. Single crystal refers to a crystal that grows evenly in all directions from a single nucleus. Its internal structure is basically a complete lattice. Single crystal technology uses special precursors and sintering processes to achieve the special structure of the crystal formed by the ternary cathode material. On the basis of maintaining the existing capacity and charge and discharge platform, it tries to increase the single crystal particle size of the cathode material, thereby increasing its tap density, increasing the volume capacity of the lithium battery, and greatly improving the safety of the lithium battery, so that the quality of the lithium battery is greatly improved. During the cycling process of polycrystalline ternary cathode materials, the accumulation of lattice strain and defects lead to lattice distortion, and grain boundary fracture (intergranular fracture) is inevitably prone to occur during the cycling process. In addition, electrolyte contact along grain boundaries and cracks in secondary particles accelerate cathode-electrolyte side reactions, leading to a transition from a layered structure to a spinel structure, ultimately causing voltage and capacity degradation. Simultaneously, particle expansion and contraction can cause the entire secondary sphere to crack and break, dramatically altering the battery's electrochemical environment and shortening the cycle life. Because the connections between small single-crystal primary particles are relatively fragile, secondary particles can easily break during the cold pressing process, which can also lead to deterioration in battery performance. Single-crystal ternary cathode materials are typically composed directly of one or several large (2-5 μm) primary irregular block particles. The material lacks grain boundaries and has a smooth microscopic surface, resulting in better structural stability and high-temperature resistance. Furthermore, after compaction and high-temperature cycling, the material is less prone to breakage, resulting in superior high-temperature cycling stability. Considering the high cost of re-synthesizing ternary cathode materials, recycling spent polycrystalline cathode materials in single-crystal form not only reduces production costs compared to traditional recycling methods, but also releases a better internal structure and repairs broken morphologies. By utilizing the defects of waste polycrystalline layered cathode materials and converting them into single crystals for regeneration, the resulting single crystal layered cathode materials have excellent structural properties. This technology not only shortens the recycling process but also has greater economic benefits and broad application prospects.

[0005] Patent application number CN202110661097.0, "A method for regenerating waste ternary positive electrode materials into single crystals," involves splitting the secondary particles of waste ternary positive electrode materials into primary particles along the grain boundaries; calcining the ternary positive electrode materials that have been split into primary particles in molten salt to cause the primary particles to nucleate and grow into single crystal particles; removing the molten salt and annealing the ternary positive electrode materials that have grown into single crystal particles to obtain single crystal ternary positive electrode materials. Patent application number CN202210097582.4, "A method for regenerating polycrystalline ternary positive electrode materials into single crystals," involves uniformly mixing a polycrystalline ternary positive electrode material with a ball milling agent and placing it in a plasma ball mill for ball milling. After the ball-milled ternary positive electrode material is broken into small particles, the plasma ball milling product is washed, filtered, and dried. It is then uniformly mixed with lithium salt and calcined in molten salt. The calcined positive electrode material is removed, washed, dried, and annealed, ultimately obtaining a single crystal positive electrode material with good crystallinity and stable structure. Although the above two methods can regenerate the polycrystalline positive electrode materials of waste ternary lithium-ion batteries into single-crystalline ternary positive electrode materials, the method of the former patent application requires long-term high-temperature roasting to split them into single-crystalline particles. Although the latter patent application uses ball milling to split the polycrystalline ternary positive electrode materials into single-crystalline positive electrode materials, its lithium replenishment process is carried out during the subsequent molten salt calcination, and subsequent annealing treatment is required, which is too cumbersome.

[0006] The present invention aims to provide a method for converting waste ternary cathode materials into single-crystal ternary cathode materials by polycrystalline fission with low roasting temperature and simple method.

[0007] Summary of the Invention

[0008] The object of the present invention is to provide a method for regenerating waste positive electrode materials into single crystals by using a vacuum cracking method.

[0009] The purpose of the present invention is achieved in this way. A method for regenerating waste positive electrode materials into single crystals using a vacuum cracking method is to fully mix and melt waste ternary lithium-ion battery polycrystalline positive electrode materials with nickel stearate and lithium salt, and then calcine them under vacuum conditions to obtain regenerated single crystal ternary positive electrode materials.

[0010] The lithium salt is a combination of lithium carbonate, lithium nitrate and lithium sulfate, and the molar ratio of lithium carbonate, lithium nitrate and lithium sulfate is 3-5:2-3:1;

[0011] The mass ratio of waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate and lithium salt is 1:0.25-2:0.4-1.1.

[0012] Preferably, the molar ratio of lithium carbonate, lithium nitrate and lithium sulfate is 4:3:1, 3:2:1 or 5:3:1.

[0013] Preferably, the lithium salt is a combination of lithium carbonate, lithium nitrate and lithium sulfate, and the lithium salt is replaced by lithium carbonate or lithium nitrate.

[0014] Preferably, the mass ratio of the waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate and lithium salt is 1:2:0.4.

[0015] Preferably, the following steps are implemented:

[0016] 1) mixing a waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate, and a lithium salt, and heating the mixture with stirring at 90-120° C. for 8-12 hours to obtain a waste ternary lithium-ion battery polycrystalline positive electrode material partially infiltrated with nickel stearate;

[0017] 2) placing the partially nickel stearate-infiltrated waste ternary lithium-ion battery polycrystalline positive electrode material in a vacuum atmosphere at a heating rate of 2-10° C. / min to 360-420° C. and sintering for 5-8 hours to obtain a waste single crystal ternary positive electrode material;

[0018] 3) The waste single crystal ternary positive electrode material is uniformly mixed in a mortar, calcined at 400-450°C for 3-6 hours in an oxygen atmosphere, then heated to 650-700°C and calcined for 6-12 hours, cooled with the furnace, washed with water, filtered, and dried at 80°C, calcined in an oxygen atmosphere at 650-700°C for 2-6 hours, and cooled with the furnace to obtain a regenerated single crystal ternary positive electrode material.

[0019] The beneficial effects of the present invention are:

[0020] 1. The method of the present invention adopting vacuum cracking method to realize single crystal regeneration of waste positive electrode materials can not only compensate for the lithium loss of single crystal waste ternary positive electrode materials, but also convert the insoluble residual Ni on the surface of the single crystal material during the "explosion" process of nickel stearate into LiNiO2 that can provide discharge capacity, so that the regenerated positive electrode material exhibits more excellent electrochemical performance, while further reducing the cost.

[0021] 2. The method of the present invention is simple, safe and easy to operate, does not require ball milling, has a short cycle, and does not require high regeneration reaction temperature (the maximum roasting temperature is only 650°C). It does not require long-term high-temperature roasting to simultaneously carry out the two processes of polycrystalline fission single crystal and lithium replenishment. The residual nickel is also reasonably converted and its value is brought into play. It has low energy consumption and is pollution-free, making it suitable for promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a SEM image of polycrystalline cathode material SNCM of waste ternary lithium-ion batteries;

[0023] FIG2 is a SEM image of the waste single crystal ternary cathode material SNCM-S of Example 1;

[0024] FIG3 is a SEM image of the regenerated polycrystalline ternary cathode material RNCM of Comparative Example 1;

[0025] FIG4 is a SEM image of the waste single crystal ternary cathode material SNCM-S1 of Comparative Example 2;

[0026] Figure 5 is a SEM image of the waste single crystal ternary cathode material SNCM-S2 of Comparative Example 3;

[0027] FIG6 is a SEM image of the regenerated single crystal ternary cathode material RSNCM of Example 1;

[0028] Figure 7 is a SEM image of the regenerated single crystal ternary cathode material RSNCM-1 of Comparative Example 2;

[0029] Figure 8 is a SEM image of the regenerated single crystal ternary cathode material RSNCM-2 of Comparative Example 3;

[0030] FIG9 is an SEM image of the regenerated single crystal ternary cathode material RSNCM-4 of Example 5;

[0031] FIG10 is an XRD pattern of the recycled single crystal cathode material (RSNCM) and the waste material (SNCM) prepared in Example 1;

[0032] 11 is a graph showing the electrochemical cycling performance of the recycled single crystal cathode material (RNCM) prepared in Example 1 and Comparative Example 1, the recycled cathode material (RSNCM-1) prepared in Comparative Example 2, and the waste material (SNCM). DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited in any way. Any changes or improvements made based on the teachings of the present invention fall within the scope of protection of the present invention.

[0034] The present invention discloses a method for regenerating waste cathode materials into single crystals by using a vacuum cracking method. The method comprises the following steps: fully mixing waste lithium-ion battery polycrystalline ternary cathode materials with nickel stearate and lithium salt, melting the mixture, and calcining the mixture under vacuum conditions to obtain regenerated single crystal ternary cathode materials.

[0035] The lithium salt is a combination of lithium carbonate, lithium nitrate and lithium sulfate, and the molar ratio of lithium carbonate, lithium nitrate and lithium sulfate is 3-5:2-3:1;

[0036] The mass ratio of waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate and lithium salt is 1:0.25-2:0.4-1.1.

[0037] The method is implemented in the following steps:

[0038] 1) mixing a waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate, and a lithium salt, and heating the mixture with stirring at 90-120° C. for 8-12 hours to obtain a waste ternary lithium-ion battery polycrystalline positive electrode material partially infiltrated with nickel stearate;

[0039] 2) placing the partially nickel stearate-infiltrated waste ternary lithium-ion battery polycrystalline positive electrode material in a vacuum atmosphere at a heating rate of 2-10° C. / min to 360-420° C. and sintering for 5-8 hours to obtain a waste single crystal ternary positive electrode material;

[0040] 3) The waste single crystal ternary positive electrode material is uniformly mixed in a mortar, calcined at 400-450°C for 3-6 hours in an oxygen atmosphere, then heated to 650-700°C and calcined for 6-12 hours, cooled with the furnace, washed with water, filtered, and dried at 80°C, calcined in an oxygen atmosphere at 650-700°C for 2-6 hours, and cooled with the furnace to obtain a regenerated single crystal ternary positive electrode material.

[0041] Example 1

[0042] 2g of waste lithium-ion battery polycrystalline ternary positive electrode material SNCM was evenly mixed with 2g of nickel stearate and 0.738g of Li2CO3, 0.517g of LiNO3, and 0.275g of Li2SO4 (molar ratio of 4:3:1), stirred at 100℃ in an electric constant temperature oil bath for 10h, and then heated at 400℃ in a vacuum environment of a tube furnace at a heating rate of 2℃ / min for 6h to obtain waste single crystal ternary positive electrode material.

[0043] The waste single crystal ternary positive electrode materials are evenly mixed in a mortar, calcined at 450°C in an oxygen atmosphere for 5 hours, then heated to 650°C and calcined for 12 hours. After washing, filtering, and drying at 80°C, they are calcined at 650°C in an oxygen atmosphere for 4 hours. The resulting solid is the recycled single crystal ternary positive electrode material.

[0044] Example 2

[0045] 2g of waste lithium-ion battery polycrystalline ternary positive electrode material SNCM was evenly mixed with 0.5g of nickel stearate and 0.738g of Li2CO3, 0.738g of LiNO3, and 0.550g of Li2SO4 (molar ratio of 2:2:1), stirred at 120℃ in an electric constant temperature oil bath for 8h, and then heated at 360℃ in a vacuum environment of a tube furnace at a heating rate of 2℃ / min for 8h to obtain waste single crystal ternary positive electrode material.

[0046] The waste single crystal ternary positive electrode material was evenly mixed in a mortar, calcined at 400°C in an oxygen atmosphere for 4 hours, then heated to 700°C and calcined for 10 hours. After washing, filtering, and drying at 80°C, it was calcined at 700°C in an oxygen atmosphere for 2 hours to obtain a regenerated single crystal ternary positive electrode material.

[0047] Example 3

[0048] 2g of waste lithium-ion battery polycrystalline ternary positive electrode material SNCM was evenly mixed with 1g of nickel stearate and 0.246g of Li2CO3, 0.460g of LiNO3, and 0.366g of Li2SO4 (molar ratio of 3:2:1), stirred at 110℃ in an electric constant temperature oil bath for 10h, and then heated at 380℃ in a vacuum environment of a tube furnace at a heating rate of 2℃ / min for 7h to obtain waste single crystal ternary positive electrode material.

[0049] The waste single crystal ternary positive electrode materials were evenly mixed in a mortar, calcined at 425°C in an oxygen atmosphere for 6 hours, then heated to 650°C and calcined for 8 hours. After washing, filtering, and drying at 80°C, they were calcined at 650°C in an oxygen atmosphere for 6 hours to obtain recycled single crystal ternary positive electrode materials.

[0050] Example 4

[0051] 2g of waste lithium-ion battery polycrystalline ternary positive electrode material SNCM was evenly mixed with 4g of nickel stearate and 0.739g of Li2CO3, 0.414g of LiNO3, and 0.220g of Li2SO4 (molar ratio of 5:3:1), stirred at 90℃ in an electric constant temperature oil bath for 12h, and then heated at 420℃ in a vacuum environment of a tube furnace at a heating rate of 2℃ / min for 5h to obtain waste single crystal ternary positive electrode material.

[0052] The waste single crystal ternary positive electrode material was evenly mixed in a mortar, calcined at 450°C in an oxygen atmosphere for 5 hours, then heated to 650°C and calcined for 12 hours. After washing with water, filtering, and drying at 80°C, it was calcined at 700°C in an oxygen atmosphere for 6 hours to obtain a pretreated regenerated single crystal positive electrode material. The pretreated regenerated single crystal positive electrode material was washed with water and dried, and calcined at 700°C in an oxygen atmosphere for 4 hours to obtain a regenerated single crystal ternary positive electrode material.

[0053] Example 5

[0054] The method of this embodiment is basically the same as that of Example 1, and the lithium salt is 0.8 g of lithium carbonate (Li2CO3).

[0055] Example 6

[0056] The method of this embodiment is basically the same as that of Example 1, and the lithium salt is 0.6 g of lithium nitrate (LiNO3).

[0057] Comparative Example 1

[0058] In this comparative example, nickel stearate was not added, and the other steps were the same as those in Example 1.

[0059] Comparative Example 2

[0060] In this comparative example, the heating rate under vacuum environment is 5°C / min, and the other steps are the same as those in Example 1.

[0061] Comparative Example 3

[0062] In this comparative example, the heating rate under vacuum environment is 10°C / min, and the other steps are the same as those in Example 1.

[0063] Test Example 1

[0064] The waste single crystal positive electrode materials and the regenerated positive electrode materials prepared in Example 1, Example 5 and Comparative Examples 1, 2 and 3 were subjected to SEM detection, and the detection results are shown in Figures 1-9.

[0065] As can be seen from Figures 1-9, the waste ternary lithium-ion battery polycrystalline positive electrode material SNCM (Figure 1) is a spherical secondary particle formed by the accumulation of primary particles. The particle size is 8-10nm, and cracks appear on the surface and white flocs are attached, which may be residual PVDF and conductive carbon. The waste single crystal positive electrode material obtained in Example 1 (Figure 2) "explodes" into large-area independent primary particles, and the material obtained in Comparative Example 1 (Figure 3) is still in the form of secondary particles, and has not "exploded" into single crystal particles, and the surface microcracks have not been completely repaired. The "exploded" waste single crystal positive electrode material particles obtained in Comparative Examples 2 and 3 still retain larger spherical secondary particles (Figures 4-5), indicating that the excessively high heating rate cannot fully ensure that the polycrystalline particles are better "exploded" into primary particles. The regenerated single crystal positive electrode material (Figure 6) obtained by regeneration in Example 1 presents primary particles, and the surface of the regenerated material is smooth, without cracks and impurities, and single crystal LiNiO2 is present. The synthesized single crystal LiNiO2 is a long strip of primary particles, which is significantly different from the primary particles of the ternary material, but has a smooth surface and no impurities and cracks. However, since Comparative Examples 2 and 3 do not "explode" into primary particles (Figures 7-8) during the single crystallization process, the regenerated materials agglomerate over a large area, and the synthesized LiNiO2 and the single crystal ternary positive electrode material agglomerate together and adhere to the surface of the polycrystalline material that has not been exploded, which is not conducive to the deintercalation of lithium ions, and will greatly affect the electrochemical properties of the regenerated materials and cannot meet the material requirements.

[0066] In contrast, the regenerated positive electrode material ( FIG9 ) obtained after regeneration using lithium carbonate (Li 2 CO 3 ) as the sole lithium source in Example 5 has no microcracks, and the crystal surface is relatively clear, but there is still a small-scale agglomeration phenomenon, and a small amount of lithium salt is attached, so the lithium ion transmission resistance is increased, and the degree of repair of the positive electrode material is not as good as that in Example 1.

[0067] Test Example 2

[0068] The waste lithium-ion battery ternary cathode material (SNCM) and the recycled single crystal cathode material (RSNCM) prepared in Example 1 were subjected to XRD detection, and the detection results are shown in FIG10 .

[0069] As shown in Figure 10, the spectra of SNCM and RSNCM both show similar diffraction peaks, which are basically consistent with the standard LiNiO2 spectrum PDF#09-0063, and are typical hexagonal layered LiNiO2 structures with R-3m space group. The diffraction peaks of SNCM material become flatter than those of RSNCM material, and (006) and (012) merge, (108) and (110) merge, and the splitting is not obvious. These phenomena all indicate that the crystallinity of the waste polycrystalline positive electrode (SNCM) material has decreased and the crystal structure has been damaged to a certain extent, which may be caused by irreversible phase transition during the charge and discharge process. The XRD spectrum of the regenerated RSNCM material shows sharper diffraction peaks, and the splitting of the (006) / (012) and (108) / (110) diffraction characteristic peaks is more obvious, indicating that the material has a better layered structure. The sharper diffraction peaks also indicate that the crystallinity of the material has been largely restored. In addition, no other impurity peaks were found in the XRD pattern of the SRNCM material, which indicates that the method of the present invention does not introduce new impurity phases and effectively converts the residual Ni compounds on the surface into LiNiO2 that can provide capacity, which is consistent with the SEM analysis in Figure 5 above.

[0070] Test Example 3

[0071] The battery cycling performance of the waste lithium-ion battery ternary cathode material (SNCM), the recycled single crystal cathode material (RSNCM) prepared in Example 1, the recycled cathode material (RNCM) prepared in Comparative Example 1, and the recycled single crystal cathode material (RSNCM-1) prepared in Comparative Example 2 were tested. The battery cycling results are shown in Table 1 and Figure 11.

[0072] The results show that the first cycle discharge capacity of the regenerated single crystal ternary cathode material (RSNCM) in Example 1 can reach 206.198 mAh g -1 , which is significantly higher than the 162.687 mAhg of the recycled positive electrode material (RNCM) prepared in Comparative Example 1. -1 , and 192.772mAhg of the recycled single crystal cathode material RSNCM-1 in comparative example 2 -1This is due to the partial capacity provided by the conversion of residual Ni to LiNiO2, while the capacity of the original waste single-crystal cathode material is restored after sufficient lithium compensation. After 100 cycles, the capacity retention rate of the RSNCM material is 86.7%, significantly higher than that of the recycled cathode material (RNCM) prepared in Comparative Example 1 and the recycled single-crystal cathode material (RSNCM-1) prepared in Comparative Example 2, indicating that the electrochemical performance of the material has been restored and can meet the requirements of use.

[0073] Table 1 Battery charge and discharge test of the regenerated positive electrode materials prepared in Example 1, Comparative Example 1 and Comparative Example 2

[0074] Test results

[0075] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for regenerating waste positive electrode materials into single crystals by vacuum cracking, characterized in that: The waste ternary lithium-ion battery polycrystalline positive electrode material is fully mixed with nickel stearate and lithium salt, and then melted and calcined under vacuum conditions to obtain a regenerated single crystal ternary positive electrode material; The lithium salt is a combination of lithium carbonate, lithium nitrate and lithium sulfate, and the molar ratio of lithium carbonate, lithium nitrate and lithium sulfate is 3-5:2-3:1; The mass ratio of polycrystalline positive electrode material, nickel stearate and lithium salt of waste ternary lithium-ion batteries is 1:0.25-2:0.4-1.

1.

2. The method for realizing single crystal regeneration of waste positive electrode materials by vacuum cracking method according to claim 1, characterized in that: The molar ratio of lithium carbonate, lithium nitrate and lithium sulfate is 4:3:1, 3:2:1 or 5:3:

1.

3. The method for realizing single crystal regeneration of waste positive electrode materials by vacuum cracking method according to claim 1 or 2, characterized in that: The lithium salt is a combination of lithium carbonate, lithium nitrate and lithium sulfate, and the lithium salt is replaced by lithium carbonate or lithium nitrate.

4. The method for realizing single crystal regeneration of waste positive electrode materials by vacuum cracking method according to claim 1 or 2, characterized in that: The mass ratio of the waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate and lithium salt is 1:2:0.

4.

5. The method for realizing single crystal regeneration of waste positive electrode materials by vacuum cracking method according to claim 1, characterized in that: To achieve this, follow these steps: 1) Mixing waste ternary lithium-ion battery polycrystalline positive electrode material, nickel stearate and lithium salt, and stirring and heating at 90-120° C. for 8-12 hours to obtain waste ternary lithium-ion battery polycrystalline positive electrode material partially infiltrated with nickel stearate; 2) placing the waste ternary lithium-ion battery polycrystalline positive electrode material partially infiltrated with nickel stearate in a vacuum atmosphere, heating the temperature to 360-420° C. at a heating rate of 2-10° C. / min, and sintering for 5-8 hours to obtain a waste single crystal ternary positive electrode material; 3) After uniformly mixing the waste single crystal ternary positive electrode material in a mortar, calcining at 400-450° C. for 3-6 hours in an oxygen atmosphere, heating to 650-700° C. for calcining for 6-12 hours, cooling with the furnace, washing, filtering, drying at 80° C., calcining at 650-700° C. for 2-6 hours, cooling with the furnace, and obtaining a regenerated single crystal ternary positive electrode material.

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