Method and device for recycling positive and negative electrode materials of waste lithium ion battery and product

Abstract

This application pertains to the field of waste battery recycling and discloses a method, apparatus, and product for recycling positive and negative electrode materials from waste lithium-ion batteries. Specifically, it involves pre-treating waste lithium-ion batteries to obtain a mixture of positive and negative electrode materials, and then mixing the mixture with a eutectic salt to obtain a mixture to be separated. The density of the eutectic salt is 2.5 g / cm³. 3 ~3.5g / cm 3 Within a certain range; the mixture to be separated is heated to above the eutectic point of the eutectic salt, the upper solid layer is collected to obtain regenerated negative electrode material, and the lower solid layer is collected to obtain regenerated positive electrode material. This application utilizes the eutectic salt with a density between the positive and negative electrode materials, which allows the negative electrode material to float and the positive electrode material to sink, thereby effectively achieving the separation and regeneration of positive and negative electrode materials from waste lithium-ion batteries. This is beneficial for subsequent reuse and has the advantages of simple process and low cost, making it suitable for mass production.

Description

Technical Field

[0001] This application pertains to the field of waste battery recycling, and more specifically, relates to methods, apparatus, and products for recycling positive and negative electrode materials of waste lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries dominate the energy storage and electrification fields due to their high power density and environmental friendliness, experiencing explosive growth in shipments over the past decade. However, given that lithium-ion batteries typically have a lifespan of less than ten years, a wave of their retirement is imminent. Fluctuations in material costs and limited resources of key materials have led to severe material supply problems for lithium-ion batteries, particularly for the high-value positive and negative electrode materials. Therefore, there is an urgent need to develop efficient electrode material recycling technologies.

[0003] The recycling processes using hydrometallurgical and pyrometallurgical methods are cumbersome, have low return on investment, and generate secondary pollution, making them unsuitable for industrial production. Direct regeneration of LIBs electrode materials has attracted widespread attention due to its economic and environmental advantages. It can maintain the chemical structure of the electrode materials while recycling them, and is expected to become the next generation of low-energy, economical, and environmentally friendly industrial applications. However, conventional direct regeneration processes require a single positive or negative electrode material, but in reality, the resulting mixture is usually a mixture of positive, negative, and black powder. Achieving precise separation of the positive and negative electrode materials remains a challenge for industry. The inability to separate the positive and negative electrode materials means that the positive electrode material can only be recycled using pyrometallurgical or hydrometallurgical techniques, following a "material" to "element" technical route, significantly increasing the recycling process and wasting the potential value of the materials. Summary of the Invention

[0004] In view of the shortcomings of the prior art, this application provides a method, apparatus and product for recycling positive and negative electrode materials of waste lithium-ion batteries, aiming to solve the problem that the existing recycling process cannot achieve the separation of positive and negative electrode materials.

[0005] According to one aspect of this application, a method for recycling positive and negative electrode materials from spent lithium-ion batteries is provided, specifically including:

[0006] S1 pre-treats spent lithium-ion batteries to obtain a mixture of positive and negative electrode materials. Then, this mixture is mixed with a eutectic salt to obtain a mixture to be separated. The density of the eutectic salt is 2.5 g / cm³. 3 ~3.5g / cm 3 Within the range;

[0007] S2 heats the mixture to be separated to above the eutectic point of the eutectic salt, collects the upper solid material to obtain regenerated negative electrode material, and collects the lower solid material to obtain regenerated positive electrode material.

[0008] Compared with the prior art, the above-described technical solution conceived in this application utilizes a eutectic salt with a density between that of the negative electrode material and the positive electrode material to directly achieve the separation and regeneration of the positive and negative electrode materials. This enables a recycling and regeneration technology route that goes directly from "material" to "material", effectively simplifying the recycling process and offering advantages such as simple process and low cost.

[0009] As a further preferred embodiment, the eutectic salt contains 5% to 35% Li, based on molar content. + The anions in the eutectic salt include more than 15% NO3. - .

[0010] This application optimizes the types and contents of cations and anions in eutectic salts, enabling the simultaneous recycling and regeneration of positive and negative electrode materials from spent lithium-ion batteries, further simplifying the recycling process.

[0011] As a further preferred method, the regenerated negative electrode material is collected by combining airflow intake with filtration.

[0012] As a further preferred option, in step S1, the pretreatment of the waste lithium-ion battery specifically involves: crushing the waste lithium-ion battery and heating it at 300℃~450℃ for 0.5h~1h, and then screening out sheet-like materials with a size greater than 20μm to obtain a mixed material of positive electrode material and negative electrode material.

[0013] As a further preferred embodiment, the eutectic salt, based on molar content, further comprises 35%–70% density-regulating cations, with the remainder being melting point cations. The density-regulating cations are alkali metal or alkaline earth metal ions with atomic numbers greater than 40, such as Cs. + Ba 2+ One or more of the following, wherein the melting point adjusting cation is an alkali metal or alkaline earth metal ion with an atomic number less than 21, such as K + Ca 2+ One or more of the following; the anion in the eutectic salt also includes Br. - I - OH - ClO4 - One or more of the following. Alkali metal and alkaline earth metal ions are preferred because their outermost electron shells have only 1 or 2 electrons, respectively. The resulting salts are relatively stable with few valence changes and are not easily decomposed by heat, thus reducing additional side reactions.

[0014] As a further preferred embodiment, the mass percentage of the co-molten salt in the mixture to be separated is greater than 2 / 3.

[0015] As a further preferred embodiment, the regenerated negative electrode material is cleaned and then placed in an inert atmosphere and annealed at 700℃~900℃ for 1h~2h to improve the charge-discharge cycle stability of the regenerated negative electrode material.

[0016] As a further preferred embodiment, the recycled cathode material is cleaned and then annealed in an oxygen-containing or inert atmosphere at 800℃~950℃ for 4h~8h to improve the charge-discharge cycle stability of the recycled cathode material. The ternary material and lithium cobalt oxide material are in an oxygen atmosphere, while the lithium iron phosphate material is in an inert atmosphere.

[0017] According to another aspect of this application, regenerated negative electrode materials and / or regenerated positive electrode materials prepared using the above-described recycling method are provided.

[0018] According to another aspect of this application, a device for recycling positive and negative electrode materials of waste lithium-ion batteries is provided. The recycling device includes a separation unit and a negative electrode collection unit. The separation unit is used to contain a mixture to be separated obtained by mixing the positive and negative electrode materials of waste lithium-ion batteries with a eutectic salt, and to heat the mixture to be separated to above the eutectic point of the eutectic salt, so that the recycled negative electrode material floats up and the recycled positive electrode material sinks down.

[0019] The negative electrode collection unit includes a transport pipe, a collection chamber, a filter membrane, and a suction pump. One end of the transport pipe extends into the separation unit and is located above the liquid surface, while the other end extends into the collection chamber. The outlet of the collection chamber is equipped with a filter membrane. The suction pump is connected to the outlet of the collection chamber, and the suction port of the suction pump is located in the internal space of the filter membrane, so as to collect the regenerated negative electrode material that does not wet the eutectic salt and floats on the surface by means of airflow.

[0020] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages:

[0021] 1. The recycling method provided in this application does not require the separation of positive and negative electrode materials during the crushing stage. It can achieve the separation and regeneration of positive and negative electrode materials of waste lithium-ion batteries in one step by using eutectic salt with a density between that of positive and negative electrode materials. This opens up a brand-new recycling and regeneration technology route from "material" to "material", which effectively simplifies the recycling process and has the advantages of simple process and low cost. It is suitable for mass production, and the positive and negative electrode materials obtained are of high purity and have few impurities.

[0022] 2. In particular, this application optimizes the types and contents of cations and anions in the eutectic salt, utilizing Li + Ensure sufficient lithium supply for structural repair of failed cathode materials during the recycling process, and NO3 - It can convert lithium in residual electrolyte, SEI, dead lithium, and other substances on the graphite surface back into Li.+ The process fully utilizes the residual lithium source to transform it into an external lithium replenishing agent for the failed positive electrode material, which is then filled into the lattice of the failed positive electrode material. This enables the simultaneous separation and regeneration of the positive and negative electrode materials of waste lithium-ion batteries and reduces the need for additional lithium replenishing agents. The entire process greatly simplifies the recycling process of the positive and negative electrode materials of waste lithium-ion batteries.

[0023] 3. In addition, experiments have shown that the negative electrode material does not wet the eutectic salt. Therefore, the negative electrode material floating on the surface of the molten salt is in the form of loose particles. Thus, this application uses airflow suction combined with filtration to collect the regenerated negative electrode material, which has the advantages of simple process and low cost. Attached Figure Description

[0024] Figure 1 This is a flowchart of the method for recycling positive and negative electrode materials of waste lithium-ion batteries provided in the embodiments of this application;

[0025] Figure 2 This is a schematic diagram of a waste lithium-ion battery positive and negative electrode material recycling device provided in an embodiment of this application.

[0026] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0027] 1-Separation unit, 2-Transport pipeline, 3-Collection bin, 4-Filter membrane, 5-Suction pump. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] like Figure 1 As shown, according to one aspect of this application, a method for recycling positive and negative electrode materials from waste lithium-ion batteries is provided, specifically including:

[0030] S1 pre-processes spent lithium-ion batteries to obtain a mixture of positive and negative electrode materials. This mixture is then combined with a eutectic salt to obtain a separate mixture. The eutectic salt is composed of two or more salts, and its eutectic point is lower than the melting point of a single salt, typically between 150°C and 400°C. Furthermore, the density of the eutectic salt is approximately 2.5 g / cm³. 3 ~3.5g / cm 3 Within a certain range, the density is between that of the positive electrode material and the negative electrode material;

[0031] S2 heats the mixture to be separated to above the eutectic point of the eutectic salt, due to the density of the negative electrode material (2.2 g / cm³). 3 ~2.4g / cm3 The density of the cathode material is less than that of the eutectic salt, thus causing it to float. The density of the cathode material is 3.6 g / cm³. 3 The material above has a density greater than that of the eutectic salt, so it will sink, thus achieving the separation of positive and negative electrode materials. Finally, the upper solid material is collected to obtain regenerated negative electrode material, and the lower solid material is collected to obtain regenerated positive electrode material, thereby realizing the recycling of positive and negative electrode materials of waste lithium-ion batteries.

[0032] The recycling method provided in this application does not require separating the positive and negative electrode materials during the crushing stage. It can separate the positive and negative electrode materials of waste lithium-ion batteries by using a eutectic salt with a density between that of the positive and negative electrode materials. This opens up a brand-new recycling and regeneration technology route from "material" directly to "material", which effectively simplifies the recycling process and has the advantages of simple process and low cost. It is suitable for mass production, and the positive and negative electrode materials obtained are of high purity and have few impurities.

[0033] Furthermore, based on molar content, the cations in the eutectic salt include 5% to 35% Li. + Li + The content of [specific element] should not be less than 5% to ensure sufficient lithium source for structural repair of failed cathode materials, and should not be more than 35% to ensure that the lower limit of the density of the eutectic salt system is higher than 2.5 g / cm³. 3 The eutectic salt contains more than 15% NO3 as anion. - It can completely remove impurities remaining on the graphite surface while lowering the melting point of the eutectic salt system. Specifically, due to the NO3 in the eutectic salt... - The oxidation process can convert lithium in the residual electrolyte, SEI, dead lithium, and other substances on the graphite surface back into Li. + This allows the external lithium replenishing agent, used as a filler for the failed cathode material, to be added to the lattice of the failed cathode material, thereby simultaneously achieving the separation and regeneration of the cathode and anode materials and reducing the need for additional lithium replenishing agent.

[0034] This application optimizes the types and contents of cations and anions in eutectic salts, enabling the simultaneous recycling and regeneration of positive and negative electrode materials from waste lithium-ion batteries. Compared with existing technologies that separate separation and regeneration processes, this application further simplifies the recycling process, reduces recycling costs, and has the potential for large-scale industrial application.

[0035] Furthermore, in step S1, the pretreatment of waste lithium-ion batteries specifically involves: crushing the waste lithium-ion batteries and heating them at 300℃~450℃ for 0.5h~1h to degrade the binder in the electrode sheets, thereby separating the active material from the current collector. Then, sheet-like materials with a size greater than 20μm, such as the battery casing, separator, and current collector, are screened out to obtain a mixed material of positive and negative electrode materials. No additional pretreatment process is required; conventional pretreatment methods combined with subsequent processes are sufficient to recycle the positive and negative electrode materials of waste lithium-ion batteries.

[0036] Furthermore, in step S2, the negative electrode material does not wet the eutectic salt, so the negative electrode material floating on the surface of the molten salt is in the form of loose particles. With the help of the air suction and filtration device, the floating negative electrode material is continuously collected by air suction and filtration, so as to achieve precise separation of the positive and negative electrode mixture to obtain pure positive and negative electrode materials. At the same time, due to the non-wetting characteristics of the negative electrode material and the eutectic salt, the separation of the negative electrode material is very convenient, efficient and simple.

[0037] Furthermore, based on molar content, the eutectic salt also includes 35%–70% density-adjusting cations to regulate the density range of the eutectic salt system to meet separation requirements; the remainder are melting point-adjusting cations. Specifically, when Li… + When the content of density-adjusting cations reaches 100%, other cations may be excluded. Preferably, the density-adjusting cations include Cs. + Ba 2 + One or more of the alkali metals or alkaline earth metals with atomic numbers greater than 40, and melting point regulating cations including K. + Ca 2 + One or more of the alkali metal or alkaline earth metal ions with atomic numbers less than 21. The anions in eutectic salts also include Br. - I - OH - ClO4 - One or more of the following. Alkali metal and alkaline earth metal ions are preferred because their outermost electron shells have only 1 and 2 electrons, respectively. The resulting salts are relatively stable with few valence changes and are not easily decomposed by heat, thus reducing additional side reactions.

[0038] Furthermore, the mass ratio of the co-molten salt in the mixture to be separated is greater than 2 / 3, in order to achieve a better separation effect between the positive and negative electrode materials.

[0039] Furthermore, the regenerated negative electrode material is washed with deionized water 2-3 times and then placed in an inert atmosphere and annealed at 700℃-900℃ for 1-2 hours to repair the small number of structural defects inside the graphite and improve the charge-discharge cycle stability of the regenerated negative electrode material.

[0040] Furthermore, the regenerated cathode material is washed with deionized water 2-3 times and then placed in an oxygen-containing atmosphere (air atmosphere or pure oxygen atmosphere) or an inert atmosphere (argon atmosphere) and annealed at 800℃-950℃ for 4-8 hours to eliminate residual lithium salts on the surface of the failed cathode material during the water washing process and stabilize the crystal structure of the regenerated cathode material to improve charge-discharge cycle stability.

[0041] According to another aspect of this application, regenerated negative electrode materials and / or regenerated positive electrode materials prepared using the above-described recycling method are provided.

[0042] In the method for recycling and utilizing the positive and negative electrode materials of waste lithium-ion batteries provided in this application, the positive electrode material of the lithium-ion battery is a ternary material or / and lithium cobalt oxide material or / and lithium iron phosphate material, and the negative electrode material is graphite.

[0043] The chemical formula of the ternary material is: LiNi 1-x-y Co x Mn y O2, 0 < x < 1, 0 < y < 1, 1-xy:x:y is 1:1:1, 4:2:4, 5:2:3, 6:2:2 or 8:1:1;

[0044] The chemical formula of lithium cobalt oxide is LiCoO2.

[0045] The chemical formula of lithium cobalt oxide is LiFePO4.

[0046] According to another aspect of this application, such as Figure 2 As shown, a waste lithium-ion battery positive and negative electrode material recycling device is provided. The recycling device includes a separation unit 1 and a negative electrode collection unit. The separation unit 1 is used to contain the mixture to be separated obtained by mixing the waste lithium-ion battery positive and negative electrode materials with eutectic salt, and to heat the mixture to be separated to above the eutectic point of the eutectic salt, so that the recycled negative electrode material floats up and the recycled positive electrode material sinks down.

[0047] The negative electrode collection unit includes a transport pipe 2, a collection chamber 3, a filter membrane 4, and an air pump 5. The front end of the transport pipe 2 extends into the separation unit 1 and is located above the liquid surface, while its rear end extends into the collection chamber 3. The front end adopts a narrow opening to improve suction. The filter membrane 4 is fixed inside the collection chamber 3 at the upper outlet position. The air pump 5 is placed above the collection chamber 3 and connected to the collection chamber 3 through a pipe. The air pump 5 generates suction, and the floating regenerated negative electrode material is sent into the collection chamber 3 for collection by airflow. The tail end of the transport pipe 2 is below the filter membrane 4, and the suction port of the air pump 5 is inside the filter membrane 4. With the help of suction, the negative electrode material is filtered and enriched in the collection chamber 3 at both ends. The advantage of this design is that it can prevent the filter membrane 4 from clogging and achieve long-term operation.

[0048] The technical solutions provided in this application will be further described below with reference to specific embodiments.

[0049] Example 1

[0050] The positive electrode that caused the performance failure is LiNi. 0.5 Co 0.2 Mn 0.3 The battery fragments, made of O2 (abbreviated as NCM523) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM523 and graphite.

[0051] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium nitrate, cesium nitrate, and potassium nitrate at a mass ratio of 1:3 to obtain the mixture to be separated. The molar ratio of lithium nitrate, cesium nitrate, and potassium nitrate in the eutectic salt was 1:2:1, and at this ratio, the density of the eutectic salt was 2.84 g / cm³. 3 .

[0052] The mixture to be separated is heated to 150°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM523 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0053] The dispersed NCM523 and graphite were washed twice with deionized water. After drying, the NCM523 was annealed at 900°C for 4 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) formed on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM523 cathode material and a graphite anode material.

[0054] Example 2

[0055] The positive electrode that caused the performance failure is LiNi. 0.6 Co 0.2 Mn 0.2 The battery fragments, made of O2 (abbreviated as NCM622) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 450℃ for 0.5h to remove flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, and finally obtained a powder mixture of NCM622 and graphite.

[0056] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium hydroxide, potassium nitrate, and barium nitrate at a mass ratio of 1:5 to obtain the mixture to be separated. The molar ratio of lithium nitrate, cesium nitrate, and potassium nitrate in the eutectic salt was 1:5:6, and the density of the eutectic salt was 3.05 g / cm³. 3 .

[0057] The mixture to be separated is heated to 300°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM622 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0058] The dispersed NCM622 and graphite were washed twice with deionized water. After drying, the NCM622 was annealed at 850°C for 6 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 850°C for 1 hour in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM622 cathode material and a graphite anode material.

[0059] Example 3

[0060] The positive electrode that caused the performance failure is LiNi. 0.8 Co 0.1 Mn 0.1 The battery fragments, made of O2 (abbreviated as NCM811) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 350℃ for 1 h. Subsequently, flaky materials with a particle size greater than 20 μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM811 and graphite.

[0061] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium bromide, cesium nitrate, and calcium nitrate at a mass ratio of 1:3 to obtain the mixture to be separated. The molar ratio of lithium bromide, cesium nitrate, and calcium nitrate in the eutectic salt was 3:5:1, and the density of the eutectic salt was 3.25 g / cm³. 3 .

[0062] The mixture to be separated is heated to 350°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM811 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0063] The dispersed NCM811 and graphite were washed twice with deionized water. After drying, the NCM811 was annealed at 800°C for 6 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 700°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a ternary 811 cathode material and a graphite anode material that could be commercially reused.

[0064] Example 4

[0065] The positive electrode that failed to perform is LiC. O O2 (LCO) material, with graphite as the negative electrode, is used in the battery fragmentation process. The fragmented battery is washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments are filtered and collected, then treated at 450℃ for 0.5 h. Flake-like materials with a particle size greater than 20 μm, such as the battery casing, separator, and current collector, are then sieved to remove them, yielding a powder mixture of LCO and graphite.

[0066] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium bromide and cesium nitrate at a mass ratio of 1:4 to obtain the mixture to be separated. The molar ratio of lithium bromide to cesium nitrate in the eutectic salt was 1:2, and at this ratio, the density of the eutectic salt was 3.32 g / cm³. 3 .

[0067] The mixture to be separated is heated to 320°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the LCO that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0068] The dispersed LCO and graphite were washed twice with deionized water. After drying, the LCO was annealed at 950°C for 6 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 800°C for 1 hour in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product yielded commercially viable LCO cathode and graphite anode materials.

[0069] Example 5

[0070] The positive electrode that caused the performance failure is LiNi. 0.5 Co 0.2 Mn 0.3 The battery fragments, made of O2 (abbreviated as NCM523) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM523 and graphite.

[0071] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium nitrate and cesium perchlorate at a mass ratio of 1:3 to obtain the mixture to be separated. The molar ratio of lithium nitrate to cesium perchlorate in the eutectic salt was 1:4, and at this ratio, the density of the eutectic salt was 3.02 g / cm³. 3 .

[0072] The mixture to be separated is heated to 180°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM523 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0073] The dispersed NCM523 and graphite were washed twice with deionized water. After drying, the NCM523 was annealed at 900°C for 4 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM523 cathode material and a graphite anode material.

[0074] Example 6

[0075] The positive electrode that caused the performance failure is LiNi. 0.5 Co 0.2 Mn 0.3 The battery, made of O2 (abbreviated as NCM523) material and graphite as the negative electrode, was broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were collected by filtration and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM523 and graphite.

[0076] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium nitrate and cesium hydroxide at a mass ratio of 1:4 to obtain the mixture to be separated. The molar ratio of lithium nitrate to cesium hydroxide in the eutectic salt was 1:3, and at this ratio, the density of the eutectic salt was 2.92 g / cm³. 3 .

[0077] The mixture to be separated is heated to 320°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM523 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0078] The dispersed NCM523 and graphite were washed twice with deionized water. After drying, the NCM523 was annealed at 900°C for 4 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM523 cathode material and a graphite anode material.

[0079] Example 7

[0080] The battery with a failed cathode (lithium iron phosphate, LFP) and a cathode (graphite) is broken up. The broken battery fragments are washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments are filtered and collected, then treated at 300°C for 1 hour. Flake-like materials with a particle size greater than 20 μm, such as the battery casing, separator, and current collector, are then sieved to remove them, resulting in a powder mixture of LFP and graphite.

[0081] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium bromide and cesium nitrate at a mass ratio of 1:4 to obtain the mixture to be separated. The molar ratio of lithium bromide to cesium nitrate in the eutectic salt was 1:5, and at this ratio, the density of the eutectic salt was 3.35 g / cm³. 3 .

[0082] The mixture to be separated is heated to 280°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the LFP that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0083] The dispersed LFP and graphite were washed twice with deionized water. After drying, the LFP was annealed at 800°C for 2 hours in a hydrogen-argon mixed gas atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the water washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable LFP cathode material and a graphite anode material.

[0084] Example 8

[0085] The positive electrode that caused the performance failure is LiNi. 0.5 Co 0.2 Mn 0.3 The battery fragments, made of O2 (abbreviated as NCM523) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM523 and graphite.

[0086] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium bromide and potassium bromide at a mass ratio of 1:3 to obtain the mixture to be separated. The molar ratio of lithium bromide to potassium bromide in the eutectic salt was 3:2, and at this ratio, the density of the eutectic salt was 3.15 g / cm³. 3 .

[0087] The mixture to be separated is heated to 480°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM523 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0088] The dispersed NCM523 and graphite were washed twice with deionized water. After drying, the NCM523 was annealed at 900°C for 4 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM523 cathode material and a graphite anode material.

[0089] Example 9

[0090] The positive electrode that caused the performance failure is LiNi. 0.5 Co 0.2 Mn 0.3The battery fragments, made of O2 (abbreviated as NCM523) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM523 and graphite.

[0091] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium bromide, lithium fluoride, and lithium chloride at a mass ratio of 1:4 to obtain the mixture to be separated. The molar ratio of lithium bromide, lithium fluoride, and lithium chloride in the eutectic salt was 2:3:2, and the density of the eutectic salt was 3.1 g / cm³. 3 .

[0092] The mixture to be separated is heated to 450°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM523 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0093] The dispersed NCM523 and graphite were washed twice with deionized water. After drying, the NCM523 was annealed at 900°C for 4 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM523 cathode material and a graphite anode material.

[0094] Example 10

[0095] The positive electrode that caused the performance failure is LiNi. 0.3 Co 0.3 Mn 0.3 The battery, made of O2 (abbreviated as NCM333) material and graphite as the negative electrode, was broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM333 and graphite.

[0096] The fragment mixture obtained above was mixed thoroughly with a eutectic salt of lithium nitrate, cesium nitrate, and potassium nitrate at a mass ratio of 1:3 to obtain the mixture to be separated. The molar ratio of lithium nitrate, cesium nitrate, and potassium nitrate in the eutectic salt was 1:2:1, and at this ratio, the density of the eutectic salt was 2.84 g / cm³. 3 .

[0097] The mixture to be separated is heated to 150°C, at which temperature the eutectic salt melts. Since graphite and the eutectic salt are not wettable, the graphite floats on the surface of the eutectic salt and appears as a loose powder. At this point, a suction device is used to continuously draw the floating graphite into a collection chamber for enrichment. After the graphite is completely collected, the molten salt is poured out to collect the NCM333 that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0098] The dispersed NCM333 and graphite were washed twice with deionized water. After drying, the NCM333 was annealed at 900°C for 4 hours in air to remove residual lithium compounds (such as lithium carbonate) formed on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM333 cathode material and a graphite anode material.

[0099] Example 11

[0100] The positive electrode that caused the performance failure is LiNi. 0.5 Co 0.2 Mn 0.3 The battery fragments, made of O2 (abbreviated as NCM523) material and graphite as the negative electrode, were broken up. The broken battery fragments were washed with deionized water 1-3 times to remove the electrolyte. After washing, the battery fragments were filtered and collected, and then treated at 300℃ for 1 hour. Subsequently, flaky materials with a particle size greater than 20μm, such as battery casing, separator, and current collector, were screened out to obtain a powder mixture of NCM523 and graphite.

[0101] The fragment mixture obtained above was mixed with lithium bromide at a mass ratio of 1:3 to obtain the mixture to be separated. The density of the lithium bromide molten salt is 3.46 g / cm³. 3 .

[0102] The mixture to be separated was heated to 480°C, at which temperature lithium bromide melts. Since the graphite floating on the surface is wettable to the molten lithium bromide salt, it is difficult to collect using a suction device. In this case, a continuous sifting method with a screen is used to filter and collect the floating graphite. After the graphite has been completely collected, the molten salt is poured out to collect the NCM523 material that has settled at the bottom. The poured-out molten salt is collected and retained for the next operation.

[0103] The dispersed NCM523 and graphite were washed twice with deionized water. After drying, the NCM523 was annealed at 900°C for 4 hours in an oxygen atmosphere to remove residual lithium compounds (such as lithium carbonate) generated on the material surface during the washing process. The graphite was annealed at 800°C for 2 hours in an argon atmosphere to eliminate minor structural defects within the graphite structure. The final product was a commercially viable NCM523 cathode material and a graphite anode material.

[0104] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for recycling positive and negative electrode materials of waste lithium ion batteries, characterized in that, Specifically, it includes: S1 pre-treats spent lithium-ion batteries to obtain a mixture of positive and negative electrode materials, with graphite as the negative electrode material. Then, the mixture is mixed with a eutectic salt to obtain a mixture to be separated. The density of the eutectic salt is 2.5 g / cm³. 3 ~3.5g / cm 3 Within the range, based on molar content, the cations in the eutectic salt include 5% to 35% Li. + The anions in the eutectic salt include more than 15% NO3. - ; S2 heats the mixture to be separated to above the eutectic point of the eutectic salt. The negative electrode material graphite is not wettable to the eutectic salt. Graphite floats on the surface of the eutectic salt and is in the form of loose powder. The regenerated negative electrode material that is not wettable to the eutectic salt and floats on the surface is collected by airflow to obtain the regenerated negative electrode material. The lower solid material is collected to obtain the regenerated positive electrode material.

2. The recycling method of claim 1, wherein, The regenerated negative electrode material is collected by a combination of airflow intake and filtration.

3. The recycling method of claim 1, wherein, In step S1, the pretreatment of waste lithium-ion batteries specifically involves: crushing the waste lithium-ion batteries and heating them at 300℃~450℃ for 0.5h~1h, and then sieving out sheet materials with a size greater than 20μm to obtain a mixed material of positive electrode material and negative electrode material.

4. The recycling method of claim 1, wherein, Based on molar content, the eutectic salt further comprises 35%–70% density-regulating cations, with the remainder being melting point-regulating cations. The density-regulating cations are alkali metal or alkaline earth metal ions with atomic numbers greater than 40, and the melting point-regulating cations are alkali metal or alkaline earth metal ions with atomic numbers less than 21. The eutectic salt also contains Br⁻ anions. - I - OH - ClO4 - One or more of them.

5. The recycling method of claim 1, wherein, The mass percentage of the co-molten salt in the mixture to be separated is greater than 2 / 3.

6. The recovery method according to any one of claims 1 to 5, characterized in that, After cleaning, the regenerated negative electrode material is placed in an inert atmosphere and annealed at 700℃~900℃ for 1h~2h to improve the charge-discharge cycle stability of the regenerated negative electrode material.

7. The recovery method according to any one of claims 1 to 5, characterized by, After cleaning, the regenerated cathode material is placed in an oxygen-containing or inert atmosphere and annealed at 800℃~950℃ for 4h~8h to improve the charge-discharge cycle stability of the regenerated cathode material.

8. Regenerated negative electrode material and / or regenerated positive electrode material prepared by the recycling method according to any one of claims 1 to 7.

9. A device for recycling positive and negative electrode materials of waste lithium-ion batteries, implementing the recycling method as described in any one of claims 1 to 7, characterized in that, The recycling device includes a separation unit (1) and a negative electrode collection unit. The separation unit (1) is used to contain the mixture to be separated obtained by mixing the positive and negative electrode materials of waste lithium-ion batteries with eutectic salt, and to heat the mixture to be separated to above the eutectic point of the eutectic salt, so that the recycled negative electrode material floats up and the recycled positive electrode material sinks down. The negative electrode collection unit includes a transport pipe (2), a collection chamber (3), a filter membrane (4), and a suction pump (5). One end of the transport pipe (2) extends into the separation unit (1) and is located above the liquid surface, while the other end extends into the collection chamber (3). The outlet of the collection chamber (3) is provided with a filter membrane (4). The suction pump (5) is connected to the outlet of the collection chamber (3), and the suction port of the suction pump (5) is located in the internal space of the filter membrane (4) to collect the regenerated negative electrode material that does not wet the eutectic salt and floats on the surface by means of airflow suction.

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