A method for regenerating waste lithium-ion battery positive electrode material

Abstract

The invention discloses a method for regenerating positive electrode materials of waste lithium-ion batteries, which comprises the following steps: discharging and disassembling waste lithium-ion batteries to obtain positive electrode sheets and negative electrode materials of waste lithium-ion batteries, pre-treating the positive electrode sheets of waste lithium-ion batteries to obtain positive electrode material powder of waste lithium-ion batteries; mixing the negative electrode materials of waste lithium-ion batteries with NaCl solution and a promoter to obtain a first solution and performing a hydrothermal reaction, evaporating and crystallizing to obtain LiCl powder; mixing the LiCl powder with an organic solvent and an activator to perform a saponification reaction to obtain a second solution; mixing the second solution with the positive electrode material powder of waste lithium-ion batteries to obtain a third solution; drying the third solution to obtain positive electrode material powder; and quenching the positive electrode material powder to obtain a regenerated positive electrode material of lithium-ion batteries. The method of the invention can efficiently regenerate the positive electrode materials of waste lithium-ion batteries and restore their excellent electrochemical properties.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery regeneration, and in particular to a method for regenerating anode materials of waste lithium ion batteries. Background Art

[0002] my country is now facing the triple pressure of increasing dependence on foreign fossil energy, engine technology being controlled by others, and serious automobile exhaust pollution. It has become an urgent task to develop sustainable new energy and build a low-carbon society. The development of new energy vehicles is an inevitable choice for my country to "change lanes and overtake". Lithium-ion batteries have also attracted much attention as a new type of high-energy green battery with advantages such as high specific capacity, low self-discharge, and long life. The sharp increase in the output of lithium-ion batteries will inevitably lead to a large consumption of manufacturing resources. In particular, it has imposed a heavy burden on the supply of rare metals such as lithium (Li) and cobalt (Co) for metal minerals. Lithium, cobalt, and nickel are the focus of resource competition among countries. my country lacks cobalt and nickel, and its dependence on foreign countries exceeds 70%. The mining and extraction of lithium metal is very complicated and expensive. Therefore, waste lithium-ion batteries can be regarded as "artificial minerals" for extracting metals. The recycling of waste lithium-ion batteries can reduce environmental pollution and effectively alleviate the demand for metal resources such as lithium and cobalt. The resource utilization of waste lithium-ion batteries can not only realize the resource utilization of limited resources and drive the development of the circular economy, but also avoid potential threats to human health and the ecological environment. It has multiple benefits such as resources, economy and society. Therefore, the resource utilization technology of waste lithium-ion batteries has important significance and practical value.

[0003] With the vigorous development of the global new energy industry, the commercialized positive electrode materials for lithium-ion batteries include lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, ternary materials, etc. At present, the recycling methods for waste lithium-ion battery positive electrode materials mainly include pyrometallurgy, hydrometallurgy and direct regeneration. Direct regeneration technology can effectively avoid the problem of difficult later separation and purification of complex positive electrode materials by repairing lithium-ion battery positive electrode materials and regenerating new lithium-ion battery positive electrode materials. It can not only shorten the recycling process, but also have greater economic benefits and broader application prospects.

[0004] In the prior art, the ternary positive electrode material is directly repaired by using a high-temperature solid-phase sintering method, or the waste lithium iron phosphate battery positive electrode material is heated at high temperature to remove carbon and binder to obtain a solid powder, and then a lithium source compound and a carbon source are added to the solid mixture, and the mixture is ball-milled by a high-energy wet method. Finally, the ball-milled powder is placed in a non-oxidizing atmosphere and roasted at a high temperature to obtain a qualified lithium iron phosphate battery positive electrode material. However, although the above two methods can regenerate waste lithium-ion battery positive electrode materials, they both use high temperatures, and the high-temperature roasting time is relatively long, and they cannot efficiently regenerate waste lithium-ion battery positive electrode materials.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for regenerating positive electrode materials of waste lithium-ion batteries, aiming to solve the problem that the existing method for regenerating positive electrode materials of waste lithium-ion batteries cannot efficiently regenerate positive electrode materials of waste lithium-ion batteries.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0008] A method for regenerating waste lithium-ion battery positive electrode materials, comprising the steps of:

[0009] Discharging and disassembling the waste lithium-ion batteries to obtain waste lithium-ion battery positive electrode sheets and waste lithium-ion battery negative electrode materials, and pre-treating the waste lithium-ion battery positive electrode sheets to obtain waste lithium-ion battery positive electrode material powder;

[0010] The waste lithium-ion battery negative electrode material is mixed with a NaCl solution and a promoter to obtain a first solution, and subjected to a hydrothermal reaction, and evaporated and crystallized to obtain LiCl powder;

[0011] The LiCl powder is mixed with an organic solvent and an activator to perform a saponification reaction to obtain a second solution;

[0012] Mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a third solution;

[0013] Drying the third solution to obtain positive electrode material powder;

[0014] The positive electrode material powder is quenched to obtain a regenerated lithium-ion battery positive electrode material.

[0015] The method for regenerating waste lithium-ion battery positive electrode materials, wherein the solid-liquid mass ratio in the first solution is 1:(5-10).

[0016] The method for regenerating waste lithium-ion battery positive electrode materials, wherein the temperature of the hydrothermal reaction is 200-240° C., and the time is 10-30 minutes.

[0017] In the method for regenerating waste lithium-ion battery positive electrode materials, the organic solvent is one or more of urea, acetamide, and thiourea.

[0018] The method for regenerating waste lithium-ion battery positive electrode materials, wherein the activator is ethyl acetate or 2-ethylhexyl phosphate mono-2-ethylhexyl ester.

[0019] The method for regenerating the positive electrode material of waste lithium-ion batteries, wherein the step of mixing the second solution with the positive electrode material powder of waste lithium-ion batteries to obtain the third solution specifically comprises:

[0020] Mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a mixed solution;

[0021] The mixed solution is used as an anode and a direct current is passed through the mixed solution for electrolysis.

[0022] The method for regenerating the positive electrode material of waste lithium-ion batteries, wherein during the electrolysis process, the voltage drop between the cathode and the anode is 8 to 10V.

[0023] The method for regenerating waste lithium-ion battery positive electrode materials, wherein the quenching treatment is specifically: heating to 500-700°C at a heating rate of 10°C / min at room temperature, keeping the temperature for 4 hours, cooling to 100°C at a cooling rate of 8°C / min, and then cooling naturally.

[0024] The method for regenerating the positive electrode material of waste lithium-ion batteries, wherein the steps of discharging and disassembling the waste lithium-ion batteries to obtain the positive electrode sheets of waste lithium-ion batteries and the negative electrode materials of waste lithium-ion batteries, and pretreating the positive electrode sheets of waste lithium-ion batteries to obtain the positive electrode material powder of waste lithium-ion batteries specifically include:

[0025] Soak the waste lithium-ion battery in a 3M NaCl solution for 24-48 hours to make its SOC value below 20%, and disassemble it to obtain the waste lithium-ion battery positive electrode sheet and the waste lithium-ion battery negative electrode material;

[0026] The waste lithium-ion battery positive electrode sheet is placed in a 3M NaOH solution and stirred for 10 hours, and then washed and filtered to obtain a waste lithium-ion battery positive electrode material;

[0027] The waste lithium ion battery positive electrode material is calcined at 650° C. for 5 hours to obtain waste lithium ion battery positive electrode material powder.

[0028] The method for regenerating positive electrode materials of waste lithium-ion batteries, wherein the waste lithium-ion batteries are waste lithium iron phosphate batteries or waste lithium-ion ternary batteries.

[0029] Beneficial effects: The present invention discloses a method for regenerating positive electrode materials of waste lithium-ion batteries. The present invention comprises the following steps: mixing negative electrode materials obtained by discharging and disassembling waste lithium-ion batteries with NaCl for hydrothermal treatment to obtain LiCl as a lithium source; then mixing LiCl with an organic solvent and an activator for saponification to obtain a medium with multiple binding sites; the lithium source can react with the positive electrode materials of waste lithium-ion batteries in the medium to achieve repair of the positive electrode materials of waste lithium-ion batteries; and then drying and quenching treatments are performed to obtain regenerated positive electrode materials of lithium-ion batteries. The method of the present invention can efficiently regenerate positive electrode materials of waste lithium-ion batteries and restore their excellent electrochemical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention provides a flowchart of a preferred embodiment of a method for regenerating positive electrode materials of waste lithium-ion batteries.

[0031] Figure 2 The XRD patterns of RNCM-622 and SNCM-622 in Example 1 are shown in FIG.

[0032] Figure 3 The SEM images of RNCM-622 and SNCM-622 in Example 1.

[0033] Figure 4 This is the electrochemical performance diagram of RNCM-622 and SNCM-622 in Example 1.

[0034] Figure 5 Impedance diagram of RNCM-622 and SNCM-622 in Example 1. DETAILED DESCRIPTION

[0035] The present invention provides a method for regenerating anode materials of waste lithium-ion batteries. To make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. 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.

[0036] In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0037] In addition, the terms "first" and "second" are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of ordinary technicians in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as here.

[0038] In the prior art, the ternary positive electrode material is directly repaired by using a high-temperature solid-phase sintering method, or the waste lithium iron phosphate battery positive electrode material is heated at high temperature to remove carbon and binder to obtain a solid powder, and then a lithium source compound and a carbon source are added to the solid mixture, and the mixture is ball-milled by a high-energy wet method. Finally, the ball-milled powder is placed in a non-oxidizing atmosphere and roasted at a high temperature to obtain a qualified lithium iron phosphate battery positive electrode material. However, although the above two methods can regenerate waste lithium-ion battery positive electrode materials, they both use high temperatures, and the high-temperature roasting time is relatively long, and they cannot efficiently regenerate waste lithium-ion battery positive electrode materials.

[0039] Based on this, the present invention provides a method for regenerating the positive electrode material of waste lithium-ion batteries, see Figure 1 , which comprises the steps of:

[0040] S10, discharging and disassembling the waste lithium ion battery to obtain a waste lithium ion battery positive electrode sheet and a waste lithium ion battery negative electrode material, and pretreating the waste lithium ion battery positive electrode sheet to obtain a waste lithium ion battery positive electrode material powder;

[0041] S20, mixing the waste lithium-ion battery negative electrode material with a NaCl solution and a promoter to obtain a first solution and subjecting the solution to a hydrothermal reaction, evaporation and crystallization to obtain LiCl powder;

[0042] S30, mixing the LiCl powder with an organic solvent and an activator to perform a saponification reaction to obtain a second solution;

[0043] S40, mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a third solution;

[0044] S50, drying the third solution to obtain positive electrode material powder;

[0045] S60, quenching the positive electrode material powder to obtain a regenerated lithium-ion battery positive electrode material.

[0046] Specifically, the present invention mixes the negative electrode material obtained by discharging and disassembling the waste lithium ion battery with NaCl and performs hydrothermal treatment to obtain LiCl as a lithium source, and then mixes LiCl with an organic solvent and an activator to perform saponification reaction to obtain a medium with multiple binding sites. The lithium source can react with the positive electrode material of the waste lithium ion battery in the medium to achieve the repair of the positive electrode material of the waste lithium ion battery, and then the regenerated positive electrode material of the lithium ion battery can be obtained through drying and quenching treatment. The method of the present invention has a short experimental process, simple operation, no high-temperature treatment is required, low energy consumption, is more environmentally friendly and green, and can efficiently regenerate the positive electrode material of the waste lithium ion battery and restore its excellent electrochemical performance.

[0047] At present, the recycling and reuse methods of waste lithium-ion battery positive electrode materials include pyrometallurgical recycling, hydrometallurgical recycling, and material regeneration. Although pyrometallurgy is simple to operate and has high productivity, it has the disadvantages of high energy consumption, emission of harmful gases and high equipment requirements; hydrometallurgy faces the problem of long process and the acid and alkali by-products produced during the smelting process have the risk of polluting the environment. Material regeneration includes indirect regeneration and direct regeneration of materials. Although the indirect regeneration method can control the purity of the precursor, the production process is complicated and requires the use of corrosive solvents, which is easy to cause secondary pollution; direct regeneration directly separates the positive electrode material through a pretreatment process, and then the attenuated positive electrode material is treated with lithium supplementation. The existing direct regeneration methods include high-temperature solid phase method, electrochemical method, hydrothermal method, and molten salt method. High-temperature solid phase is to complete the regeneration process by mixing waste materials and lithium salts at 800-1000℃, repair the crystal structure of lithium cobalt oxide, and realize the direct regeneration of waste lithium cobalt oxide positive electrode materials. However, the high-temperature solid phase method has high requirements for the precursor of the material, and uneven lithium mixing will lead to uneven final products. In addition, the reaction temperature is high, the sintering time is long, the energy consumption is high, and the electrochemical performance of the regenerated positive electrode material needs to be improved; the electrochemical method is a very promising material separation and regeneration technology, which can use electrodeposition or electrochemical insertion to produce useful materials, with less waste or less demand for reagents, but the electrochemical method has limited recovery of material properties and has high requirements for precursor materials; the hydrothermal method refers to the use of aqueous solution as the reaction medium in a special closed container (autoclave), and by heating the reaction container to create a high temperature of 100-1000℃ and a high pressure environment of 1-100MPa, so that the usually insoluble or insoluble substances are dissolved and recrystallized, achieving low energy consumption, and having the advantages of being compatible with batteries under different capacity decay conditions, short time, and good electrochemical performance of the regenerated positive electrode material. Therefore, the present invention adopts a method that combines hydrothermal method with electrochemical method to regenerate waste positive electrode materials more efficiently, greener and safer to restore their electrochemical properties. In addition, the method of the present invention does not require knowing the amount of lithium deficiency in the original waste positive electrode materials, nor does it require ICP testing. The waste positive electrode materials can be directly supplemented with lithium.

[0048] In some embodiments, in step S20, the mass ratio of the negative electrode material to the NaCl solution and the promoter is 1:(5-10):(1-3), and the promoter is an oxidizing substance, preferably hydrogen peroxide in this embodiment.

[0049] In some embodiments, the solid-liquid (solid refers to the graphite negative electrode material of the waste lithium-ion battery) mass ratio in the first solution is 1: (5-10), the temperature of the hydrothermal reaction is 200-240° C., and the time is 10-30 min. Since the lithium ions in the negative electrode of the waste lithium-ion battery are Li x It exists in the form of C6 compounds, so lithium ions can be quickly extracted by adding a promoter and a NaCl solution to undergo a hydrothermal reaction, and then LiCl powder can be obtained through impurity removal, evaporation and crystallization.

[0050] In some embodiments, the hydrothermal reaction is specifically as follows: adding the first solution mixed evenly to the inner lining of the hydrothermal kettle and then placing it in the hydrothermal kettle, placing the hydrothermal kettle in a forced air drying oven, the temperature is 200-240°C, and the time is 10-30 minutes. During the hydrothermal reaction, the solution is used as a medium, and a high temperature and high pressure reaction environment is created by heating the reaction container to convert LiC6 in the graphite into Li + Extracted, and the promoter promotes Li by oxidizing substances + Extract this process.

[0051] In some embodiments, the organic solvent is one or more of urea, acetamide, and thiourea.

[0052] In some embodiments, the activator is ethyl acetate or 2-ethylhexyl mono-2-ethylhexyl phosphate.

[0053] Specifically, the organic solvent is used as a carrier, and the activator is used to activate the organic solvent for saponification reaction. The activator undergoes a hydrolysis reaction under alkaline conditions to generate hydroxyl groups, which attack alkoxy groups, and alkoxy groups leave to generate alcohol and carboxylate (taking ethyl acetate as an example, ethyl acetate is hydrolyzed into ethanol and carboxylate under alkaline conditions), so that the mixed solution after saponification becomes a medium with multiple binding sites, and LiCl can react with the cathode material of the waste lithium-ion battery in this medium, so as to realize the repair of the cathode material of the waste lithium-ion battery.

[0054] In some embodiments, the step of mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a third solution specifically includes:

[0055] Mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a mixed solution;

[0056] The mixed solution is used as an anode and a direct current is passed through the mixed solution for electrolysis.

[0057] In some embodiments, during the electrolysis process, the voltage drop between the cathode and the anode is 8 to 10 V, the cathode is a platinum sheet, the anode is a waste lithium-ion battery positive electrode material, and the electrolyte is the second solution.

[0058] Specifically, the electrolysis method can promote the lithium ions to enter the cathode material of the waste lithium-ion battery under the action of the external current, further strengthening the lithiation effect, so that not only the existing material in the anode area has a certain reducibility, but also promotes the lithiation process and the synchronous application of voltage, so that the cathode material can be better repaired. In actual production, the above process can also be omitted, and the second solution can be mixed with the cathode material powder of the waste lithium-ion battery to spontaneously cause the lithiation reaction.

[0059] In some embodiments, the drying process is achieved using a spray dryer.

[0060] In some embodiments, the quenching treatment is specifically as follows: heating the temperature to 500-700°C at a heating rate of 10°C / min at room temperature, keeping the temperature for 4 hours, cooling to 100°C at a cooling rate of 8°C / min, and then cooling naturally. During the rapid heating process, the material structure is more likely to crack, which is beneficial to the complete lithium reaction of lithiation and avoids the generation of some undesirable impurities.

[0061] In some embodiments, the step of discharging and disassembling the waste lithium-ion battery to obtain the waste lithium-ion battery positive electrode sheet and the waste lithium-ion battery negative electrode material, and pretreating the waste lithium-ion battery positive electrode sheet to obtain the waste lithium-ion battery positive electrode material powder specifically includes:

[0062] Soak the waste lithium-ion battery in a 3M NaCl solution for 24-48 hours to make its SOC value below 20%, and disassemble it to obtain the waste lithium-ion battery positive electrode sheet and the waste lithium-ion battery negative electrode material;

[0063] The waste lithium-ion battery positive electrode sheet is placed in a 3M NaOH solution and stirred for 10 hours, and then washed and filtered to obtain a waste lithium-ion battery positive electrode material;

[0064] The waste lithium ion battery positive electrode material is calcined at 650° C. for 5 hours to obtain waste lithium ion battery positive electrode material powder.

[0065] In some embodiments, the waste lithium-ion battery is a waste lithium iron phosphate battery or a waste lithium-ion ternary battery.

[0066] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only used to illustrate the present invention but not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Example 1

[0068] A method for regenerating waste NCM-622 (denoted as SNCM-622) battery positive electrode material, comprising the steps of:

[0069] S10, soaking the waste NCM-622 battery in a 3M NaCl solution for 24 hours to make its SOC value reach 20%, disassembling to obtain a waste NCM-622 battery positive electrode sheet and a waste NCM-622 battery negative electrode material; placing the waste NCM-622 battery positive electrode sheet in a 3M NaOH solution and stirring for 10 hours, washing and filtering to obtain a waste NCM-622 battery positive electrode material; calcining the waste NCM-622 battery positive electrode material at 650° C. for 5 hours to obtain a waste NCM-622 battery positive electrode material powder;

[0070] S20, mixing the waste NCM-622 battery negative electrode material with a NaCl solution and hydrogen peroxide in a mass ratio of 1:8:2 to obtain a first solution, and subjecting the solution to a hydrothermal reaction at 220° C. for 15 min, removing impurities, and evaporating and crystallizing to obtain LiCl powder;

[0071] S30, mixing the LiCl powder with thiourea and ethyl acetate in a mass ratio of 1:1:0.2, performing a saponification reaction, and obtaining a second solution;

[0072] S40, mixing the second solution with the waste NCM-622 battery positive electrode material powder in a ratio of 100 ml: 2 g, passing direct current as an anode to electrolyze it, and the voltage drop between the cathode and the anode is 10 V, to obtain a third solution;

[0073] S50, drying the third solution in a spray dryer at 120° C. to obtain a positive electrode material powder;

[0074] S60, heating the positive electrode material powder from room temperature to 600°C at a heating rate of 10°C / min and then keeping the temperature for 4 hours, then cooling it to 100°C at a cooling rate of 8°C / min and then cooling it naturally to obtain a regenerated NCM-622 (denoted as RNCM-622) battery positive electrode material.

[0075] Figure 2 The XRD patterns of RNCM-622 and SNCM-622 in Example 1 show that all regenerated NCM-622 are consistent with the patterns of waste NCM-622, and all have a hexagonal layered α-NaFeO2 structure and belong to the R-3m space group, which indicates that the regeneration method will not destroy the original structure of NCM-622.

[0076] Figure 3 The SEM images of RNCM-622 and SNCM-622 in Example 1, wherein (a) -(c) are SEM images of RNCM-622, and (d) -(f) are SEM images of SNCM-622. It can be seen from the figure that the surface of the waste NCM-622 has obvious cracks, while the regenerated NCM-622 positive electrode material has no cracks, indicating that the structure of the positive electrode material has been well repaired by the regeneration method.

[0077] Figure 4 (a) is the 100-cycle performance diagram of RNCM-622 and SNCM-622 in Example 1. It can be seen from the figure that although the discharge of SNCM-622 in the first cycle is 160 mAh / g, it is already 135.7 mAh / g in the fourth cycle, and only 121.5 mAh / g after 100 cycles. The first-cycle discharge specific capacity of RNCM-622 can reach 166.7 mAh / g, the coulomb efficiency can reach 94.6%, and it can still reach 151.5 mAh / g after 100 cycles, and the 100-cycle retention rate is 90.8%. Figure 4 (b) is the discharge conditions of RNCM-622 and SNCM-622 in Example 1 at 0.1C, 0.2C, 0.5C, 1C, 2C, 5C, 10C, and 0.1C, and the corresponding discharge specific capacities of RNCM-622 are 156.9mAh / g, 153.9mAh / g, 151.4mAh / g, 148.1mAh / g, 142.2mAh / g, 131.2mAh / g, 119.1mAh / g, and 157.4mAh / g, respectively. It can be seen that its rate performance is better than that of SNCM-622, and its capacity can be quickly restored to the initial level from a high rate of 10C to 0.1C, indicating that it has excellent rate performance. It can be seen that the lithium supplement effect of the method of the present invention is very obvious.

[0078] Figure 5The impedance diagram of RNCM-622 and SNCM-622 in Example 1 shows that both samples RNCM-622 and SNCM-622 have typical Nyquist diagrams of ternary positive electrode materials. The surface of SNCM-622 material has higher solid electrolyte impedance and charge transfer impedance. This is because the thick DEI film on the surface of the negative electrode and the surface structure of the positive electrode material are damaged during the cycle charge and discharge process, causing the transmission of lithium ions to be blocked. The resistance values ​​of RNCM-622 are all reduced, indicating that the regeneration method has repaired the damaged structure to a certain extent, and the repair effect is significant.

[0079] In summary, the present invention discloses a method for regenerating positive electrode materials of waste lithium ion batteries, which comprises the following steps: discharging and disassembling waste lithium ion batteries to obtain positive electrode sheets and negative electrode materials of waste lithium ion batteries, pre-treating the positive electrode sheets of waste lithium ion batteries to obtain positive electrode material powder of waste lithium ion batteries; mixing the negative electrode materials of waste lithium ion batteries with a NaCl solution and a promoter to obtain a first solution, performing a hydrothermal reaction, evaporating and crystallizing to obtain LiCl powder; mixing the LiCl powder with an organic solvent and an activator, performing a saponification reaction to obtain a second solution; mixing the second solution with the positive electrode material powder of waste lithium ion batteries to obtain a third solution; drying the third solution to obtain positive electrode material powder; and quenching the positive electrode material powder to obtain a regenerated positive electrode material of lithium ion batteries. The invention comprises the following steps: mixing the negative electrode material obtained by discharging and disassembling the waste lithium ion battery with NaCl for hydrothermal treatment to obtain LiCl as a lithium source; then mixing the LiCl with an organic solvent and an activator for saponification reaction to obtain a medium with multiple binding sites; the lithium source can react with the positive electrode material of the waste lithium ion battery in the medium to achieve the repair of the positive electrode material of the waste lithium ion battery; and then drying and quenching treatment to obtain the regenerated positive electrode material of the lithium ion battery. The method of the invention can efficiently regenerate the positive electrode material of the waste lithium ion battery and restore its excellent electrochemical performance.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for regenerating anode materials of waste lithium-ion batteries, characterized in that: Includes steps: Discharging and disassembling the waste lithium-ion batteries to obtain waste lithium-ion battery positive electrode sheets and waste lithium-ion battery negative electrode materials, and pre-treating the waste lithium-ion battery positive electrode sheets to obtain waste lithium-ion battery positive electrode material powder; The waste lithium-ion battery negative electrode material is mixed with a NaCl solution and a promoter hydrogen peroxide to obtain a first solution and subjected to a hydrothermal reaction, and evaporated and crystallized to obtain LiCl powder, wherein the temperature of the hydrothermal reaction is 200-240° C. and the time is 10-30 min; The LiCl powder is mixed with an organic solvent and an activator to perform a saponification reaction to obtain a second solution, wherein the organic solvent is one or more of urea, acetamide, and thiourea, and the activator is ethyl acetate or 2-ethylhexyl mono-2-ethylhexyl phosphate; Mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a third solution; Drying the third solution to obtain positive electrode material powder; The positive electrode material powder is quenched to obtain a regenerated lithium-ion battery positive electrode material. The quenching treatment is specifically: heating to 500-700°C at a heating rate of 10°C / min at room temperature, keeping the temperature for 4 hours, cooling to 100°C at a cooling rate of 8°C / min, and then cooling naturally.

2. The method for regenerating the positive electrode material of waste lithium-ion batteries according to claim 1, characterized in that: The solid-liquid mass ratio in the first solution is 1:(5-10).

3. The method for regenerating the positive electrode material of waste lithium-ion batteries according to claim 1, characterized in that: The step of mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a third solution specifically comprises: Mixing the second solution with the waste lithium-ion battery positive electrode material powder to obtain a mixed solution; The mixed solution is used as an anode and a direct current is passed through the mixed solution for electrolysis.

4. The method for regenerating the positive electrode material of waste lithium-ion batteries according to claim 3, characterized in that: During the electrolysis process, the voltage drop between the cathode and the anode is 8-10V.

5. The method for regenerating the positive electrode material of waste lithium-ion batteries according to claim 1, characterized in that: The steps of discharging and disassembling the waste lithium-ion batteries to obtain waste lithium-ion battery positive electrode sheets and waste lithium-ion battery negative electrode materials, and pretreating the waste lithium-ion battery positive electrode sheets to obtain waste lithium-ion battery positive electrode material powder specifically include: Soaking the waste lithium-ion battery in a 3M NaCl solution for 24-48 hours until the SOC value of the waste lithium-ion battery reaches less than 20%, and disassembling the waste lithium-ion battery to obtain a positive electrode sheet and a negative electrode material of the waste lithium-ion battery; The waste lithium-ion battery positive electrode sheet is placed in a 3M NaOH solution and stirred for 10 hours, and then washed and filtered to obtain a waste lithium-ion battery positive electrode material; The waste lithium ion battery positive electrode material is calcined at 650° C. for 5 hours to obtain waste lithium ion battery positive electrode material powder.

6. The method for regenerating the positive electrode material of waste lithium-ion batteries according to claim 1, characterized in that: The waste lithium-ion battery is a waste lithium iron phosphate battery or a waste lithium-ion ternary battery.

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