Method for regulating crystal phase defect in direct regeneration process of waste ternary material

Abstract

The invention discloses a method for regulating and controlling crystal phase defects in a direct regeneration process of a waste ternary material, and belongs to the technical field of waste battery recovery. The method comprises the following steps: placing a waste ternary material with lattice defects in an oxidizing atmosphere for impurity removal and calcination to obtain a decarbonized and defluorinated waste ternary material; and ball-milling and mixing the decarbonized and defluorinated waste ternary material, a lithium source and a fluorine-free carbon source, and carrying out two-stage pyrogenic process calcination in an oxygen-containing atmosphere to obtain the regenerated ternary material. According to the method, direct regeneration of the waste ternary material is achieved through a solid-phase sintering method under the condition that no miscellaneous elements are introduced, and the regenerated ternary material is excellent in electrochemical performance and can be compared favorably with a commercial ternary positive electrode material.

Description

Technical Field

[0001] This invention relates to a method for regenerating waste ternary materials, and particularly to a method for controlling crystal phase defects during the direct regeneration of waste ternary materials, belonging to the field of waste battery recycling technology. Background Technology

[0002] Lithium-ion battery ternary materials (LiNi) x Co y Mn z O2 (Lithium-ion batteries) have high capacity and high energy density, making them one of the most widely used commercial cathode materials. However, after long-term charge-discharge cycles, ternary electrode materials will exhibit harmful behaviors such as lithium migration, interlayer damage, and lithium-nickel reverse positioning, leading to a decline in the electrochemical performance of ternary materials and ultimately forcing the retirement of commercial ternary batteries.

[0003] Currently, the cycle life of commercially available ternary lithium batteries is 5-8 years, and it is estimated that by 2030, the total amount of retired commercial ternary lithium batteries will reach 1 million tons per year. Waste ternary lithium batteries contain abundant nickel, cobalt, manganese, and lithium elements, making them economically valuable. Current recycling methods for waste ternary lithium batteries mainly include pyrometallurgical, hydrometallurgical, and direct recycling processes. The pyrometallurgical process primarily alloys the metal elements in the waste ternary materials at high temperatures, followed by acid leaching to promote element separation. The hydrometallurgical process mainly uses large amounts of acid to completely dissociate the waste ternary materials, followed by separate extraction and removal of the elements.

[0004] However, the aforementioned element extraction methods, categorized as element extraction methods, suffer from problems such as high pollution and energy consumption, resulting in low economic value. Direct regeneration technology, as a novel recycling method, has received widespread attention. It primarily restores the performance of recycled materials by recovering and controlling the failed crystalline phase. However, current waste battery materials originate from manufacturing processes dating back over 10 years, resulting in poor intrinsic properties that fail to meet the demands of modern energy storage systems. Therefore, there is an urgent need for upgraded regeneration research on waste battery materials. The presence of crystalline phase defects is a key factor affecting recycled materials. Traditional defect control methods mostly involve introducing impurities through doping. However, national standards impose strict content controls on impurities, and the introduction of impurities reduces the stability of the layered structure of recycled materials and triggers some side reactions.

[0005] Therefore, there is an urgent need to develop a method for controlling crystal phase defects without introducing impurities during the direct regeneration process. Summary of the Invention

[0006] To address the technical deficiencies in existing technologies, the present invention aims to provide a method for controlling crystal phase defects during the direct regeneration of waste ternary materials. This method uses waste ternary materials as direct raw materials and achieves direct regeneration of waste ternary materials without introducing impurities through solid-state sintering. Furthermore, the regenerated ternary materials exhibit excellent electrochemical performance, comparable to commercial ternary cathode materials.

[0007] To achieve the above-mentioned technical objectives, this invention provides a method for controlling crystal phase defects during the direct regeneration of waste ternary materials. This invention involves placing waste ternary materials with crystal defects in an oxidizing atmosphere for impurity removal and calcination to obtain decarbonized and defluorinated waste ternary materials. The decarbonized and defluorinated waste ternary materials are then ball-milled and mixed with a lithium source and a non-fluorinated carbon source, and then placed in an oxygen-containing atmosphere for two-stage pyrometallurgical calcination to obtain regenerated ternary materials.

[0008] The key to this invention lies in the following: pyrometallurgical sintering in an oxidizing atmosphere removes fluorine and carbon, followed by lithium and carbon replenishment, and then two-stage pyrometallurgical calcination. This process effectively controls defects in the material while restoring the crystal phase. In this method, although the original waste battery material carries a small amount of carbon components, including inorganic carbon black and organic carbon sources, these components cannot be directly used as defect adjusters in direct regeneration. This is because direct regeneration requires the addition of an additional lithium source for lithium replenishment. The fluorine in the PVDF of the organic carbon source will preferentially react with the lithium in the replenished lithium source, generating the byproduct lithium fluoride (LiF), leading to the failure of lithium replenishment in the final direct regeneration. Therefore, in this invention, the organic and inorganic carbon sources in the waste battery material are first removed by medium-temperature calcination in an oxidizing atmosphere, resulting in relatively pure waste ternary materials. Subsequently, in direct regeneration, by supplementing with non-F-containing carbon and lithium sources, the waste battery material is regenerated and upgraded in situ, and internal crystal phase defects are repaired, ultimately yielding high-performance regenerated ternary materials. The lithium-nickel mixture rate of the waste ternary materials used in this invention is above 7.0%, while the lithium-nickel mixture rate of the recycled ternary materials obtained through the remediation method of this invention can be reduced to below 4.4%. Simultaneously, the oxygen vacancy concentration is effectively controlled. Compared to recycled ternary materials without the addition of non-fluorinated carbon sources, the oxygen vacancy rate can be gradually adjusted with the addition of non-fluorinated carbon sources, ultimately achieving the desired electrochemical performance.

[0009] As a preferred embodiment, the particle size of the non-fluorinated carbon source is less than 1 micrometer. If the particle size of the non-fluorinated carbon source in this invention is too large, insufficient contact with the waste ternary material will lead to localized thermal carbon reduction, resulting in severe manganese segregation within the material and difficulty in restoring the crystal phase. Further, the particle size of the non-fluorinated carbon source is 200-500 nm.

[0010] As a preferred embodiment, the non-fluorinated carbon source includes at least one selected from silica, acetylene black, carbon nanotubes, graphite powder, graphene, and microcrystalline graphite. More preferably, it is selected from acetylene black and silica.

[0011] As a preferred embodiment, the amount of the non-fluorinated carbon source added is 2-8 wt% relative to the amount of the decarbonized and defluorinated waste ternary lithium-ion battery. Excessive amounts of the non-fluorinated carbon source added in this invention will lead to excessively high defect content during the regeneration process, affecting the structural stability and electrochemical performance of the regenerated material. Conversely, insufficient amounts of the non-fluorinated carbon source will also prevent the regeneration of the waste ternary lithium-ion battery performance. More preferably, the amount of the non-fluorinated carbon source added is 2-5 wt% relative to the amount of the decarbonized and defluorinated waste ternary lithium-ion battery.

[0012] As a preferred embodiment, the waste ternary material with lattice defects is selected from 523 waste ternary material, 622 waste ternary material, 7-series waste ternary material, and 8-series waste ternary material.

[0013] As a preferred embodiment, the purification calcination temperature is 400~800℃, and the time is 1h~3h. If the purification calcination temperature is too low or the time is too short, the impurity fluorine component in the material is difficult to remove completely. However, if the temperature is too high or the time is too long, the damaged grains will locally self-heal, causing partial phase segregation, making subsequent lithium replenishment difficult, thus resulting in poor performance of the regenerated ternary material. In addition, the inorganic carbon black particles in the waste ternary material are small in size and have a large active area. Furthermore, the ternary material itself acts as a carbon-based self-ignition catalyst to promote the removal of carbon impurities (including inorganic carbon black and organic carbon sources) at this temperature. Moreover, the carbon impurities always release heat during the removal process, further enhancing the removal effect. Therefore, within the temperature range of this invention, in an oxidizing atmosphere, the carbon component in the waste ternary material will combine with oxygen to generate CO2 or CO gas, which is released from the material, thereby removing the carbon component and achieving the effect of decarbonization and defluorination. More preferably, the purification calcination temperature is 400~500℃.

[0014] As a preferred embodiment, the first stage of the two-stage pyrometallurgical calcination is carried out at a temperature of 500-650℃ for 2-5 hours; the second stage is carried out at a temperature of 800-1000℃ for 8-16 hours. The first stage of calcination aims to form a layered structure for pre-repair. If the temperature is too high, the material's crystal structure will solidify, making it difficult to form a complete crystal structure. Conversely, if the temperature is too low, the crystal structure will not form completely, hindering the subsequent high-temperature solidification process. The second stage of calcination aims to further repair the crystal structure. If the sintering time is too short, the crystal structure will not form completely; conversely, if the temperature is too high or the sintering time is too long, lattice oxygen will be released, leading to a decrease in the lattice oxygen concentration in the regenerated ternary material and severe structural damage.

[0015] As a preferred embodiment, the amount of lithium source added is 1.05 to 1.2 times the theoretical value of lithium required in the recycled ternary material; the lithium source is selected from at least one of lithium hydroxide, lithium carbonate, lithium nitrate, and lithium acetate. Adding too little lithium source will result in incomplete repair of the internal crystal phase, while adding too much lithium will lead to severe alkali return in the recycled material, resulting in poor performance. In actual operation, the amount of lithium added can be calculated based on the designed ternary material system.

[0016] As a preferred embodiment, both the oxidizing atmosphere and the oxygen-containing atmosphere are oxygen atmospheres.

[0017] The waste ternary cathode material of this invention is obtained from decommissioned ternary cathode or ternary electrode material provided by enterprises. The waste ternary cathode powder is obtained through existing conventional techniques for separation.

[0018] The ball milling and other processes involved in this invention are conventional operating procedures in the prior art, and their purpose is to promote uniform mixing between different materials, which is beneficial to the restoration of the crystal phase structure.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] (1) This invention achieves the direct regeneration of waste ternary materials without introducing impurities through solid-state sintering. The regenerated ternary materials have excellent electrochemical performance, comparable to commercial ternary cathode materials.

[0021] (2) The lithium-nickel mixing rate of the waste ternary material used in this invention is above 7.0%. The lithium-nickel mixing rate of the recycled ternary material obtained by the repair method of this invention can be reduced to below 4.4%. At the same time, the oxygen vacancy concentration is effectively controlled. Compared with the recycled ternary material without the addition of non-fluorinated carbon source, the oxygen vacancy can be gradually adjusted with the addition of non-fluorinated carbon source, and finally the desired electrochemical performance is obtained.

[0022] (3) The method of the present invention is simple to operate, efficient and has a short process, which can meet the needs of large-scale production.

[0023] (4) This invention proposes for the first time a method of adding elemental carbon components as defect modifiers in the direct recycling process of waste ternary materials, thereby realizing the controllable regulation of defects in waste ternary materials and finally obtaining high-performance direct recycled materials. Attached Figure Description

[0024] Figure 1 The image shows the original XRD pattern of the waste 523-based ternary material with crystal phase defects used in Example 1.

[0025] Figure 2 The image shows the XRD pattern of the regenerated ternary material in Example 1.

[0026] Figure 3 This is the charge-discharge platform for the regenerated ternary material in Example 1.

[0027] Figure 4 This is a graph showing the cycling performance of the regenerated ternary material in Example 1.

[0028] Figure 5 This is a transmission electron microscope (TEM) image of the regenerated ternary material from Example 1. Detailed Implementation

[0029] 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.

[0030] 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 the various embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art, and such other embodiments are also within the scope of protection of the claims of this invention.

[0031] Comparative Example 1

[0032] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0033] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency and mix it with 10g of decarbonized and defluorinated waste ternary material by ball milling to obtain a mixture, thus obtaining mixed material B;

[0034] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0035] Comparative Example 2

[0036] S1: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with waste 523 series ternary material with crystal phase defects and 0.5g of acetylene black by ball milling to obtain a mixture; wherein the particle size of acetylene black is 200 nm.

[0037] S2: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0038] Example 1

[0039] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0040] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0041] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0042] Example 2

[0043] S1: Place the waste 622 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0044] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0045] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0046] Example 3

[0047] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 400℃ for 1 hour to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0048] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0049] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0050] Example 4

[0051] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 800℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0052] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0053] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0054] Example 5

[0055] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0056] S2: Weigh lithium acetate according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0057] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0058] Example 6

[0059] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0060] S2: Weigh lithium hydroxide according to 1.05 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0061] S3: Intermediate B is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550℃ for 3 hours and 900℃ for 8 hours, finally obtaining a regenerated ternary material with controllable defects.

[0062] Example 7

[0063] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0064] S2: Weigh lithium hydroxide according to 1.2 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0065] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0066] Example 8

[0067] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0068] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of silica by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0069] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0070] Example 9

[0071] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0072] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.2g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0073] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0074] Example 10

[0075] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0076] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.8g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0077] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0078] Example 11

[0079] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0080] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of microcrystalline graphite by ball milling to obtain a mixture, wherein the particle size of the microcrystalline graphite is 500nm.

[0081] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0082] Example 12

[0083] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0084] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of graphite powder by ball milling to obtain a mixture, wherein the particle size of the graphite powder is 1 micrometer.

[0085] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0086] Example 13

[0087] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0088] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0089] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 500°C for 2 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0090] Example 14

[0091] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0092] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0093] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 650°C for 5 hours and 900°C for 8 hours to finally obtain the recycled ternary material.

[0094] Example 15

[0095] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0096] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0097] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 800°C for 8 hours to finally obtain the recycled ternary material.

[0098] Example 16

[0099] S1: Place the waste 523 series ternary material with crystal phase defects in an oxygen atmosphere and calcine it at 500℃ for 3 hours to remove impurities and obtain decarbonized and defluorinated waste ternary material. The theoretical lithium deficiency of 10g of decarbonized and defluorinated waste ternary material is obtained by elemental analysis.

[0100] S2: Weigh lithium hydroxide according to 1.15 times the theoretical lithium deficiency amount and mix it with 10g of decarbonized and defluorinated waste ternary material and 0.5g of acetylene black by ball milling to obtain a mixture, wherein the particle size of acetylene black is 200nm.

[0101] S3: The mixture is placed in a tube furnace for high-temperature calcination in an oxygen atmosphere. The calcination conditions are 550°C for 3 hours and 1000°C for 16 hours to finally obtain the recycled ternary material.

[0102] The electrochemical performance test results of the ternary materials recycled in the comparative examples and embodiments, as well as the performance test results of the commercial materials, are shown in Table 1.

[0103] 1) Sample preparation

[0104] Regenerated ternary material and acetylene black were mixed and added to a pre-prepared PVDF gel (dissolved in NMP). The mass ratio of regenerated ternary 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.

[0105] 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.

[0106] Note: All comparative examples and embodiments use the electrode material preparation method described above.

[0107] 2) Testing Methods

[0108] 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.

[0109]

[0110]

[0111] Note: The commercial material in Table 1 is model NCM523, purchased from Krohde.

[0112] Figure 1 The image shows the original XRD pattern of the waste ternary material used in Example 1. It can be seen that the XRD pattern of the waste ternary material does not show obvious impurity peaks, and the Li / Ni ratio of the waste ternary material is 7.0% obtained by using the fine-tuning software, indicating a high degree of lithium-nickel mixing.

[0113] Figure 2 The image shows the XRD pattern of the regenerated ternary material in Example 1. It can be seen that the regenerated ternary material exhibits a good crystal structure, and its lithium-nickel mixing is significantly reduced to 4.4%, proving that the structure of the material has been effectively repaired.

[0114] Figure 3 The figure shows the charge-discharge platform of the regenerated ternary material in Example 1. It can be seen from the figure that the first-week capacity of the regenerated ternary material can reach 186 mAh g. -1 (0.2C), and the plateau curve is consistent with the charge-discharge plateau curve of commercial battery materials, revealing the effective recovery of material performance.

[0115] Figure 4 The charge-discharge cycle curve of the regenerated ternary material in Example 1 shows that after 100 cycles at a current density of 1.0C, the capacity of the regenerated ternary material can still be maintained at 91.3%.

[0116] Figure 5 The image shows a transmission electron microscope (TEM) image of the regenerated ternary material from Example 1. The image shows that the regenerated ternary material has a good crystal structure, indicating that the regenerated material has been effectively restored.

Claims

1. A method for controlling crystal phase defects in the direct regeneration process of waste ternary materials, characterized in that: Waste ternary materials with lattice defects are placed in an oxidizing atmosphere for impurity removal and calcination to obtain decarbonized and defluorinated waste ternary materials. The decarbonized and defluorinated waste ternary materials are then ball-milled and mixed with a lithium source and a non-fluorinated carbon source, and then placed in an oxygen-containing atmosphere for two-stage pyrolysis to obtain regenerated ternary materials.

2. The method for controlling crystal phase defects in the direct regeneration of waste ternary materials according to claim 1, characterized in that: The particle size of the non-fluorinated carbon source is less than 1 micrometer.

3. The method for controlling crystal phase defects in the direct regeneration process of waste ternary materials according to claim 1 or 2, characterized in that: The non-fluorinated carbon source includes at least one of silica, acetylene black, carbon nanotubes, graphite powder, graphene, and microcrystalline graphite.

4. The method for controlling crystal phase defects in the direct regeneration process of waste ternary materials according to claim 3, characterized in that: The amount of the non-fluorinated carbon source added is 2-8 wt% relative to the amount of the decarbonized and defluorinated waste ternary material.

5. The method for controlling crystal phase defects in the direct regeneration of waste ternary materials according to claim 1, characterized in that: The waste ternary materials with lattice defects are selected from 523 waste ternary materials, 622 waste ternary materials, 7-series waste ternary materials, and 8-series waste ternary materials.

6. A method for controlling crystal phase defects during the direct regeneration of waste ternary materials according to claim 1 or 5, characterized in that: The impurity removal and calcination temperature is 400~800℃, and the time is 1h~3h.

7. The method for controlling crystal phase defects in the direct regeneration of waste ternary materials according to claim 6, characterized in that: The first stage of the two-stage pyrometallurgical calcination is carried out at a temperature of 500-650℃ for 2-5 hours; the second stage is carried out at a temperature of 800-1000℃ for 8-16 hours.

8. The method for controlling crystal phase defects in the direct regeneration of waste ternary materials according to claim 1, characterized in that: The amount of lithium source added is 1.05 to 1.2 times the theoretical value of lithium required in the recycled ternary material; the lithium source is selected from at least one of lithium hydroxide, lithium carbonate, lithium nitrate and lithium acetate.

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