Organic eutectic salt modified, regenerated and repaired waste lithium nickel cobalt manganate positive electrode material and method

Abstract

The invention relates to an organic eutectic salt modified, regenerated and repaired waste lithium nickel cobalt manganate positive electrode material and a method, and the method comprises the following steps: uniformly mixing the waste lithium nickel cobalt manganate positive electrode material, an aluminum doping source and an organic eutectic salt to obtain mixed powder; the organic eutectic salt is a mixture of lithium hydroxide, lithium nitrate and lithium salicylate; carrying out primary calcination on the mixed powder, cooling, washing and drying to obtain a primary calcined material; and adding a lithium supplement agent into the primary calcined material, uniformly mixing, and carrying out secondary calcination to obtain the regenerated nickel cobalt lithium manganate positive electrode material. According to the method, the characteristics of high lithium ion concentration and low melting point of the organic eutectic salt are utilized, meanwhile, the organic eutectic salt can be used for modifying, regenerating and repairing the waste lithium nickel cobalt manganese oxide positive electrode material under the matching action of the aluminum doping source, and the method is simple, short in process, easy in raw material obtaining and suitable for industrial application; the regeneration effect is excellent, the initial capacity of the regenerated material is high, and the cycling stability is excellent.

Description

Technical Field

[0001] The present invention relates to the technical field of waste battery recycling and regeneration, and in particular to an organic eutectic salt modified regeneration and repair method for waste nickel cobalt manganese oxide positive electrode material. Background Art

[0002] Due to the high energy density demands of electric vehicles (EVs), lithium nickel cobalt manganese oxide (NCM) cathodes have come to dominate the development of lithium-ion batteries (LIBs). Demand for NCM in EVs is expected to surge significantly and continue to grow annually, exceeding the demand for cathodes in mobile phones and other consumer products. Over time, as EV batteries retire, the state of health (SOH) of NCM decreases. When these batteries reach a low SOH, they are no longer able to meet the demands of EVs, leading to a steady accumulation of waste NCM. If these waste batteries are not recycled, the Earth's lithium resources will be insufficient to support the growth of EVs and could pose a significant environmental threat.

[0003] Currently, conventional methods for recycling low-state-of-health batteries include hydrometallurgy and pyrometallurgy. Pyrometallurgy primarily produces transition metal alloys, but suffers from low lithium recovery rates and high energy consumption. On the other hand, while hydrometallurgical recycling achieves high recovery rates and low energy consumption, the hydrometallurgical process is complex and requires large amounts of leaching agents, reducing agents, extractants, and separators, resulting in the generation of significant amounts of wastewater.

[0004] In recent years, researchers have shown considerable interest in the direct regeneration of spent lithium-ion manganese oxide (LiMnO) cathodes. This method significantly improves the reuse rate of metal ions and shortens the regeneration process. Notably, the reagent consumption, wastewater generation, and energy requirements are all lower than those of wet and pyrometallurgical recovery processes. Key direct regeneration methods include solid-phase sintering, hydrothermal / solvothermal / ionothermal technologies, chemical relithiation, and electrochemical direct remediation. Yu et al. (Yu X, Yu S, Yang Z, et al. Achieving low-temperature hydrothermal relithiation by redox mediation for direct recycling of spent lithium-ion battery cathodes [J]. Energy Storage Materials, 2022, 51: 54−62.) employed a hydrothermal method at 220°C for lithium regeneration. Compared to solid-phase regeneration, the hydrothermal method reduces energy consumption. However, the high pressure of up to 25 bar within the hydrothermal reactor poses safety risks and is unsuitable for large-scale industrial production. Park (Park K, Yu J, Coyle J, et al. Direct cathode recycling of end-of-life Li-ion batteries enabled by redox mediation[J]. ACSSustainable Chemistry&Engineering, 2021, 9(24): 8214−8221.) et al. designed a process for electrochemical direct regeneration and repair of waste NCM. However, the efficiency of electrochemical lithium replenishment is low and is not suitable for large-scale promotion and application. Moreover, due to the complex scrapping mechanism of lithium nickel cobalt manganese oxide positive electrode materials, the positive electrode materials obtained by conventional regeneration methods often have differences in capacity and cycle performance compared with commercial materials. The current solution is usually to improve the performance of the material by modifying the material with elements. The common doping source is generally lithium hydroxide because its raw materials are easy to obtain. However, this will cause new problems. Conventional lithium source reagents usually have a high melting point, so the doping source needs to be at a higher temperature and for a longer time to evenly cover the surface of the material. In short, the above methods generally have problems such as high energy consumption, long process flow, high reagent cost, large environmental impact, and high safety risks, and cannot meet the requirements of industrial production.

[0005] In recent years, the lithiation of eutectic salts derived from molten salt electrochemistry has attracted significant research attention, primarily involving inorganic lithium salt systems such as LiCO₃-LiOH and LiNO₃-LiI. These regeneration systems offer several advantages: low melting point, low energy consumption, minimal wastewater generation, and a short process flow, making them suitable as lithium sources for modified and regenerated lithium battery cathode materials and for industrial production. However, these recharge methods are generally only suitable for the regeneration of high-capacity (capacity exceeding 70% of the original capacity) spent NCMs. Their insufficient recharge capacity for extremely low-capacity materials with pore defects and lattice structure disorder limits their application in the power battery market. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies and provide a method for modifying and regenerating waste nickel cobalt manganese oxide positive electrode materials by organic eutectic salt, so as to solve the technical problem that the effect of lithium supplementation, modification and regeneration of waste NCM positive electrode materials in the prior art is poor.

[0007] In order to achieve the above technical objectives, the technical solution provided by the present invention is: In a first aspect, the present invention provides a method for modifying, regenerating and repairing waste lithium nickel cobalt manganese oxide positive electrode materials using an organic eutectic salt, comprising the following steps: (1) uniformly mixing waste lithium nickel cobalt manganese oxide positive electrode materials, an aluminum doping source and an organic eutectic salt to obtain a mixed powder; the organic eutectic salt is a mixture of lithium hydroxide, lithium nitrate and lithium salicylate; (2) calcining the mixed powder once, and obtaining a primary calcined material after cooling, washing and drying; (3) adding a lithium supplement agent to the primary calcined material, mixing the mixture evenly and then calcining the mixture twice to obtain a regenerated lithium nickel cobalt manganese oxide positive electrode material.

[0008] In a second aspect, the present invention provides a modified regenerated lithium nickel cobalt manganese oxide positive electrode material obtained by the above method.

[0009] Compared with the prior art, the present invention has the following beneficial effects: The organic eutectic salt used in the present invention has the characteristics of high lithium ion concentration and low melting point. At the same time, under the cooperation of aluminum doping source, it can be used for more uniform modification, regeneration and repair of waste nickel cobalt manganese oxide positive electrode materials. The lithium salicylate therein can improve the oxidation ability of the entire eutectic salt in the molten state, form an oxidizing environment, and generate vacancies on the surface of the material. This environment significantly reduces the disorder of Li and Ni ions, which can effectively help Ni in waste materials 2+ Converting it into a high-valence state is beneficial to the recovery of the material's crystal structure during subsequent high-temperature calcination, thereby further improving the regeneration effect. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese oxide positive electrode materials of the present invention is simple, has a short process, and readily available raw materials, making it suitable for industrial applications. The regeneration effect is excellent, and the performance of the nickel-cobalt-manganese oxide positive electrode material obtained by modification and regeneration is comparable to that of commercial new materials. The regenerated material has a high initial capacity and excellent cycle stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Flow chart of the method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide lithium cathode material provided by the present invention; Figure 2 is an infrared spectrum of the organic eutectic salt in Example 1 of the present invention; Figure 3 is the XRD pattern of the modified recycled material obtained in Example 1 of the present invention; Figure 4 This is a constant current charge and discharge diagram of the waste material in Example 1 of the present invention at a current density of 0.5C; Figure 5 This is a constant current charge and discharge diagram of the commercial material tested in the present invention at a current density of 0.5C; Figure 6 This is a constant current charge and discharge diagram of the modified recycled material obtained in Example 1 of the present invention at a current density of 0.5C; Figure 7 This is a constant current charge and discharge diagram of the modified recycled material obtained in Example 2 of the present invention at a current density of 0.5C; Figure 8 This is a constant current charge and discharge diagram of the modified recycled material obtained in Example 3 of the present invention at a current density of 0.5C; Figure 9 This is a constant current charge and discharge diagram of the modified recycled material obtained in Example 4 of the present invention at a current density of 0.5C; Figure 10 This is a constant current charge and discharge diagram of the modified recycled material obtained in Example 5 of the present invention at a current density of 0.5C; Figure 11 This is a constant current charge and discharge diagram of the modified recycled material obtained in Comparative Example 1 of the present invention at a current density of 0.5C; Figure 12 This is a constant current charge and discharge diagram of the modified recycled material obtained in Comparative Example 2 of the present invention at a current density of 0.5C. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0012] Unless otherwise expressly stated, throughout the specification and claims, the term "comprise" or its variations such as "include" or "comprising", etc., will be understood to include the stated elements or components but not to exclude other elements or other components.

[0013] In view of the shortcomings of traditional methods for recycling waste nickel-cobalt-manganese oxide positive electrode materials and conventional regeneration methods such as serious pollution, high energy consumption or unsatisfactory regeneration effect, the present invention provides an organic eutectic salt modification, regeneration and repair method for waste nickel-cobalt-manganese oxide positive electrode materials. Lithium hydroxide, lithium nitrate and lithium salicylate are used to form an organic eutectic salt system to replenish lithium and repair waste nickel-cobalt-manganese oxide. By adjusting the mixing ratio of the eutectic salt and the waste material and using a certain amount of aluminum doping source, the modified and repaired lithium nickel-cobalt-manganese oxide positive electrode material is finally calcined and regenerated at high temperature.

[0014] First, see Figure 1 The present invention provides a method for modifying and regenerating waste nickel cobalt manganese oxide positive electrode materials using an organic eutectic salt, comprising the following steps: (1) mixing waste lithium nickel cobalt manganese oxide cathode material, aluminum doping source and organic eutectic salt to obtain mixed powder; the organic eutectic salt is a mixture of lithium hydroxide, lithium nitrate and lithium salicylate; (2) calcining the mixed powder once, cooling, washing and drying to obtain a primary calcined material; (3) Adding a lithium supplement to the primary calcined material, mixing them evenly and then performing a secondary calcination to obtain a modified and regenerated lithium nickel cobalt manganese oxide positive electrode material.

[0015] The present invention performs lithium replenishment and element doping on waste lithium nickel cobalt manganese oxide through a primary calcination, removes excess components through washing, and then adds a lithium replenisher for secondary calcination to offset lithium loss without introducing impurities, thereby obtaining a modified and regenerated lithium nickel cobalt manganese oxide positive electrode material.

[0016] Specifically, the present invention adopts lithium hydroxide, lithium nitrate and lithium salicylate to form an organic eutectic salt system, which has the characteristics of high lithium ion concentration and low melting point, and can be used to modify, regenerate and repair waste nickel cobalt manganese oxide positive electrode materials. The organic lithium salt - lithium salicylate is contained. The low melting point characteristic can make the doping elements evenly cover the material surface at a lower temperature. Lithium salicylate can improve the oxidation ability of the entire eutectic salt molten state, form an oxidizing environment, and generate vacancies on the material surface. This environment significantly reduces the disorder of Li and Ni ions, which can effectively help Ni in waste materials. 2+ Converting it into a high-valence state is beneficial to the recovery of the material's crystal structure during subsequent high-temperature calcination, thereby further improving the regeneration effect. At the same time, aluminum foil is usually used as a current collector for positive electrode materials. During the regeneration process, the present invention mixes the waste lithium nickel cobalt manganese oxide positive electrode material with an aluminum doping source and an organic eutectic salt, which plays a synergistic role, especially for the regeneration effect of extremely low-capacity waste NCM, with high capacity after regeneration and excellent cycle stability.

[0017] Preferably, in step (1), the waste nickel cobalt manganese oxide positive electrode material is obtained by disassembling the waste battery after discharging to obtain a current collector, and then peeling it from the current collector.

[0018] Further preferably, the discharge condition is: the used battery is immersed in a 10-50 g / L NaCl solution until it is completely discharged.

[0019] Further preferably, the peeling conditions include: using N-methylpyrrolidone (NMP) as a peeling agent, and peeling with the assistance of ultrasound, with the ultrasound time being 10 to 60 minutes.

[0020] The present invention adopts NMP as a stripping agent and uses ultrasound as an auxiliary means to strip the positive electrode material from the current collector without the need for additional high-temperature calcination to remove the conductive agent and the binder.

[0021] Preferably, the organic eutectic salt is a mixture of lithium hydroxide, lithium nitrate and lithium salicylate in a molar ratio of 2:3:5.

[0022] Preferably, the molar ratio of lithium element to waste lithium nickel cobalt manganese oxide in the organic eutectic salt is (0.25-2.5):1. Specifically, the molar ratio includes but is not limited to 0.25:1, 0.5:1, 0.75:1, 1:1, 1.25:1, 1.5:1, 1.75:1, 2:1, 2.25:1, 2.5:1, etc.

[0023] More preferably, the molar ratio of lithium element to waste lithium nickel cobalt manganese oxide in the organic eutectic salt is (0.5-2):1.

[0024] Preferably, the aluminum doping source is aluminum hydroxide.

[0025] Preferably, the aluminum doping source accounts for 0.5 to 2% of the molar amount of the waste lithium nickel cobalt manganese oxide.

[0026] In the present invention, when the amount of organic eutectic salt and aluminum doping source is insufficient or excessive, the modification, regeneration and repair effect of waste nickel cobalt lithium manganese oxide positive electrode materials are affected, which easily leads to a decrease in the initial capacity and capacity retention rate of the regenerated material.

[0027] Preferably, in step (2), the primary calcination is performed at 200-400°C for 3.5-4.5 hours. Specifically, the primary calcination temperature includes, but is not limited to, 200°C, 220°C, 250°C, 280°C, 300°C, 340°C, 350°C, 380°C, or 400°C; and the primary calcination time includes, but is not limited to, 3.5 hours, 4 hours, or 4.5 hours.

[0028] In the present invention, the main purpose of the first calcination is to replenish lithium under the action of the eutectic salt. At the same time, the eutectic salt can reduce the temperature of lithium replenishment. However, if the first calcination temperature is too low, the eutectic salt will not be able to melt and lithium replenishment will not be possible. If the temperature is too high, the process energy consumption will increase.

[0029] Preferably, in step (2), washing is performed with deionized water and ethanol for 2 to 4 times respectively; and drying is performed at 60 to 80° C. for 10 to 24 hours.

[0030] Preferably, in step (3), the lithium supplement comprises lithium carbonate.

[0031] The present invention offsets the lithium loss caused by high-temperature calcination by additionally adding a certain lithium supplement agent; at the same time, the lithium supplement agent uses lithium carbonate that is easily decomposed at high temperature, which ensures the lithium supplement effect without introducing other impurities, thereby improving the performance of the recycled material.

[0032] Preferably, in step (3), the amount of the lithium supplement agent is 0.01-5% of the mass of the primary calcined material. Specifically, the amount of the lithium supplement agent includes but is not limited to 0.01%, 0.05%, 0.1%, 0.2%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%.

[0033] Preferably, in step (3), the secondary calcination is carried out at 650-900 o Calcination at 4 to 8 hours. Specifically, the temperature of the secondary calcination includes but is not limited to 650°C, 680°C, 700°C, 720°C, 750°C, 780°C, 800°C, 830°C, 850°C or 900°C, etc.; and the time includes but is not limited to 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, etc.

[0034] In the present invention, the secondary calcination is mainly to repair the layered structure of waste lithium nickel cobalt manganese oxide. If the calcination temperature is too low, it cannot be completely repaired. If the temperature is too high, the lithium salt will evaporate, affecting the material properties.

[0035] In a second aspect, the present invention provides a modified regenerated lithium nickel cobalt manganese oxide positive electrode material obtained by the above method.

[0036] The present invention utilizes an organic eutectic salt system composed of lithium hydroxide, lithium nitrate, and lithium salicylate. This, in conjunction with an aluminum doping source, allows for more uniform modification, regeneration, and repair of waste lithium nickel-cobalt-manganese oxide cathode materials. Simultaneously, the waste lithium nickel-cobalt-manganese oxide is repaired by lithium supplementation. By adjusting the mixing ratio of the organic eutectic salt, aluminum doping source, and waste materials, the modified and repaired lithium nickel-cobalt-manganese oxide cathode material is ultimately calcined and regenerated at high temperature. The advantages of the present method include a simple process, a short flow, readily available experimental raw materials, and suitability for industrial application. Furthermore, the regeneration effect is excellent, and the resulting modified and regenerated lithium nickel-cobalt-manganese oxide cathode material has performance comparable to commercially available new materials.

[0037] This invention is based on the premise of maintaining low-carbon operation while achieving maximum economic efficiency, providing an important concept for the development of direct recycling strategies for other waste battery materials and providing technical support for the ultimate realization of industrial applications.

[0038] The present invention is further described in detail below through specific examples. The raw materials are obtained by soaking spent NCM523 lithium nickel cobalt manganese oxide batteries in a NaCl solution, discharging them, and then disassembling them after complete discharge. The disassembled positive electrode current collector is then soaked in NMP and ultrasonically exfoliated. The positive electrode powder is separated from the current collector to obtain spent NCM523 lithium nickel cobalt manganese oxide positive electrode powder (hereinafter referred to as "waste material").

[0039] Preparation of organic eutectic salt: first mix lithium hydroxide and lithium nitrate, then add organic lithium salt lithium salicylate, the molar ratio of lithium hydroxide, lithium nitrate and lithium salicylate is 2:3:5, and mix evenly to obtain organic eutectic salt.

[0040] Example 1 A method for modifying and regenerating waste nickel-cobalt-manganese oxide cathode materials using an organic eutectic salt comprises the following steps: (1) The organic eutectic salt, aluminum hydroxide and waste materials are uniformly mixed to obtain a mixed powder. The amount of the organic eutectic salt added is such that the molar ratio of its lithium content to the waste materials is 1:1, and the amount of aluminum hydroxide added is 1 mol% of the waste materials.

[0041] (2) Place the mixed powder in a muffle furnace for 5 o C / min heating rate, at 400 o After the material is cooled to room temperature, it is washed three times with deionized water and anhydrous ethanol respectively. After washing, the material is placed in an oven at 70 o C for 10 hours to obtain a primary calcined material.

[0042] (3) After the primary calcined material is completely dried, 5 wt.% Li2CO3 is added to it and the heating rate is set to 5 o C / min, at 850 o C for 6 hours, and after the temperature dropped to room temperature, a modified and regenerated lithium nickel cobalt manganese oxide positive electrode material was obtained, which was recorded as modified and regenerated material 1.

[0043] Example 2 The only difference from Example 1 is that the molar ratio of lithium element to waste material in the organic eutectic salt is 0.5:1, and the other steps and conditions are the same as those in Example 1. The obtained modified and regenerated lithium nickel cobalt manganese oxide positive electrode material is recorded as modified and regenerated material 2.

[0044] Example 3 The only difference from Example 1 is that the molar ratio of lithium element to waste material in the organic eutectic salt is 2:1, and the other steps and conditions are the same as those in Example 1. The obtained modified and regenerated lithium nickel cobalt manganese oxide positive electrode material is recorded as modified and regenerated material 3.

[0045] Example 4 The only difference from Example 1 is that the amount of aluminum hydroxide is changed to 0.5 mol%, and the other steps and conditions are the same as Example 1. The obtained modified and regenerated lithium nickel cobalt manganese oxide positive electrode material is recorded as modified and regenerated material 4.

[0046] Example 5 The only difference from Example 1 is that the amount of aluminum hydroxide is changed to 2 mol %, and the other steps and conditions are the same as Example 1. The obtained modified and regenerated lithium nickel cobalt manganese oxide positive electrode material is recorded as modified and regenerated material 5.

[0047] Comparative Example 1 The only difference from Example 1 is that lithium carbonate is selected as the lithium source to replace the organic eutectic salt. The other steps and conditions are the same as those in Example 1. The obtained modified and regenerated lithium nickel cobalt manganese oxide positive electrode material is recorded as modified and regenerated material 6.

[0048] Comparative Example 2 The only difference from Example 1 is that the lithium salicylate in the organic eutectic salt is replaced by lithium benzoate, that is, a mixture of lithium hydroxide, lithium nitrate and lithium salicylate in a molar ratio of 2:3:5 is used to replace the organic eutectic salt in Example 1. The other steps and conditions are the same as those in Example 1. The obtained regenerated lithium nickel cobalt manganese oxide positive electrode material is recorded as modified regenerated material 7.

[0049] Performance Testing 1. Infrared spectrum analysis was performed on lithium hydroxide, lithium nitrate, lithium salicylate and the organic eutectic salt in Example 1. The results were as follows: Figure 2 shown.

[0050] Depend on Figure 2 It can be found that the organic eutectic salt in Example 1 of the present invention retains the oxidized groups in lithium salicylate.

[0051] 2. XRD test was performed on the recycled material 1 obtained in Example 1. The results are as follows: Figure 3 shown.

[0052] Depend on Figure 3 From the XRD spectrum of the modified recycled material 1, it can be seen that the XRD peak of the modified recycled material 1 conforms to the characteristic peak of the standard NCM material, and a characteristic peak of aluminum doping appears, indicating that the aluminum-modified lithium nickel cobalt manganese oxide material has been successfully regenerated.

[0053] 3. The lithium nickel cobalt manganese oxide positive electrode materials obtained after modification and regeneration in the above examples and comparative examples were assembled into 2025 button half-cells, with a PP separator and a lithium sheet as the negative electrode. The initial capacity at a current density of 0.5C and the capacity retention rate after 100 cycles were measured. The waste materials and commercial materials (commercial lithium nickel cobalt manganese oxide 523 type materials) were assembled into button half-cells using the same method and the battery performance was measured. The results are shown in Table 1 and Figure 4-Figure 12 shown.

[0054] Table 1 Performance of assembled button half-cells

[0055] From Table 1 and Figure 4-12 It can be seen that the initial capacity and 100-cycle capacity retention rate of the waste materials are relatively low. Examples 1-5 are directly regenerated and repaired by the action of organic eutectic salt and aluminum hydroxide. The initial capacity and 100-cycle capacity retention rate of the obtained modified recycled materials are significantly improved, which can be equal to or even exceed the performance of commercial materials.

[0056] At the same time, it can be seen from the comparison of Examples 1-3 that when the amount of organic eutectic salt is insufficient, the capacity retention rate of the modified regenerated material is relatively poor. Therefore, the amount of organic eutectic salt in the present invention is preferably an organic eutectic salt and waste lithium nickel cobalt manganese oxide in a molar ratio of (1-2):1.

[0057] Comparison of Examples 4 and 5 shows that when the amount of doping source is too much or too little, the capacity retention rate of the modified recycled material is relatively poor. Therefore, the amount of doping source used in the present invention is preferably (0.5-2) mol% of the waste material.

[0058] In Comparative Example 1, conventional lithium carbonate was used as the lithium source, and in Comparative Example 2, lithium salicylate was replaced with lithium benzoate, resulting in the initial capacity and 100-cycle capacity retention rate of the modified regenerated material being significantly lower than those in Example 1. This indicates that the organic eutectic salt used in the present invention can achieve excellent lithium replenishment and regeneration effects.

[0059] In summary, the organic eutectic salt used in the present invention has the characteristics of high lithium ion concentration and low melting point, and can be used for more uniform modification, regeneration and repair of waste nickel cobalt manganese oxide positive electrode materials. The lithium salicylate therein can also improve the oxidation ability of the entire eutectic salt in the molten state, form an oxidizing environment, and produce vacancies on the surface of the material. This environment significantly reduces the disorder of Li and Ni ions, which is conducive to the complete recovery of the lattice structure during the subsequent high-temperature sintering process. The initial capacity of the modified waste NCM523 material regenerated by the organic eutectic salt has been restored to more than 149 mAh / g, and the capacity retention rate after 100 cycles is high (can reach 98.3%). The present invention demonstrates the potential for direct regeneration of waste nickel cobalt manganese oxide positive electrode materials and is suitable for industrial applications.

[0060] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for modifying and regenerating waste nickel-cobalt-manganese-oxide cathode materials by organic eutectic salt, characterized in that: The following steps are involved: (1) mixing waste lithium nickel cobalt manganese oxide positive electrode material, an aluminum doping source and an organic eutectic salt to obtain a mixed powder; the organic eutectic salt is a mixture of lithium hydroxide, lithium nitrate and lithium salicylate; (2) calcining the mixed powder once, cooling, washing and drying to obtain a primary calcined material; (3) Adding a lithium supplement agent to the primary calcined material, mixing them evenly, and then performing a secondary calcination to obtain a modified and regenerated lithium nickel cobalt manganese oxide positive electrode material.

2. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salt according to claim 1, characterized in that: In step (1), the waste nickel cobalt manganese oxide positive electrode material is obtained by disassembling the waste battery to obtain a current collector, and then peeling it from the current collector; The discharging step is to soak the waste battery in a NaCl solution until it is completely discharged; and the stripping step is to soak the current collector in N-methylpyrrolidone and perform ultrasonic stripping for 10 to 60 minutes.

3. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salt according to claim 1, characterized in that: In step (1), the organic eutectic salt is a mixture of lithium hydroxide, lithium nitrate and lithium salicylate in a molar ratio of 2:3:5; and / or, The molar ratio of lithium element to waste lithium nickel cobalt manganese oxide in the organic eutectic salt is (0.25-2.5):

1.

4. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salt according to claim 1, characterized in that: In step (1), the aluminum doping source is aluminum hydroxide.

5. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salt according to claim 1, characterized in that: In step (1), the aluminum doping source accounts for 0.5 to 2% of the molar amount of waste lithium nickel cobalt manganese oxide.

6. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salt according to claim 1, characterized in that: In step (2), the primary calcination is performed at 200-400° C. for 3.5-4.5 h.

7. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salts according to claim 1, characterized in that: In step (2), the washing is performed by washing with deionized water and ethanol for 2 to 4 times respectively; and the drying is performed at 60 to 80° C. for 10 to 24 hours.

8. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salts according to claim 1, characterized in that: In step (3), the lithium supplement agent includes lithium carbonate and / or lithium hydroxide; the amount of the lithium supplement agent used is 0.01 to 5% of the mass of the primary calcined material.

9. The method for modifying, regenerating and repairing waste nickel-cobalt-manganese-oxide positive electrode materials using organic eutectic salts according to claim 1, characterized in that: In step (3), the secondary calcination is carried out at 650-900 o C for 4 to 8 hours.

10. The modified regenerated lithium nickel cobalt manganese oxide positive electrode material obtained by the method according to any one of claims 1 to 9.

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