A method for recycling waste and old medium-high nickel ternary material, a regenerated material and a battery

Abstract

This invention provides a method for recycling waste high-nickel ternary materials, as well as recycled materials and batteries. The method for recycling waste high-nickel ternary materials includes: placing the waste high-nickel ternary materials in a mixed atmosphere containing CO2 and water vapor to perform a delithiation phase transition reaction, obtaining Li2CO3 and lithium-deficient materials. The recycling method provided by this invention utilizes the delithiation phase transition reaction of waste high-nickel ternary materials in a mixed atmosphere of CO2 and water vapor to achieve selective and efficient lithium extraction and enrichment, obtaining lithium-deficient materials that can be directly regenerated. This recycling method requires no external reagents or harsh conditions, has carbon emission reduction benefits, and achieves a lithium extraction rate of no less than 90%, with the obtained Li2CO3 having a purity greater than 99.5%. Furthermore, the recycled materials prepared from the lithium-deficient materials exhibit superior electrochemical performance.

Description

Technical Field

[0001] This invention belongs to the field of cathode material recycling technology, and relates to a method for recycling waste medium-high nickel ternary materials, and more particularly to a method for recycling waste medium-high nickel ternary materials, recycled materials and batteries. Background Technology

[0002] Currently, the main recycling technologies for ternary cathode materials from spent lithium-ion batteries include pyrometallurgy, hydrometallurgy, direct regeneration, and biometallurgy. Pyrometallurgy reduces metals to alloys or compounds through high-temperature smelting, offering advantages such as simple processes and large processing capacity. However, it suffers from high energy consumption (typically requiring temperatures above 1000℃), low lithium recovery rates (lithium volatilization is difficult to capture), and generates waste gas pollution. Hydrometallurgy uses acid or alkaline solutions to leach valuable metals, followed by extraction and precipitation separation for recovery. It boasts high metal recovery rates and high product purity, but the process is lengthy, consumes large amounts of acid and alkaline reagents, generates high-salt wastewater, and requires the addition of reducing agents (such as H₂O₂) during leaching to reduce high-valence Co(III) and Ni(III) to soluble states, increasing reagent costs and the risk of secondary pollution. Direct regeneration attempts to restore the electrochemical performance of materials through lithium supplementation and sintering, which has the advantages of short process and high added value. However, it cannot effectively remove impurities such as F and P remaining in the electrolyte, nor can it repair the bulk cation mixing and lattice dislocations caused by long-term cycling. The cycle life of regenerated materials is difficult to match that of the original materials (waste ternary cathode materials before use). Although biometallurgy is environmentally friendly, the reaction cycle is long and the microbial culture conditions are harsh, which currently makes it difficult to meet the needs of large-scale industrial recycling.

[0003] It is evident that the existing methods for recycling ternary cathode materials either employ a "destruction-extraction" approach (pyrometallurgy, hydrometallurgy), which completely destroys the original crystal structure and particle morphology of the cathode material during the recycling process, leading to the need for subsequent resynthesis of precursors and a significant increase in energy and material consumption; or they employ a "retention-repair" approach (direct regeneration), but this can only repair surface defects and cannot solve the problems of disordered atomic arrangement and impurity accumulation in the bulk phase; and both require high energy (heat, electricity) or chemical reagents (acids, alkalis, reducing agents) to drive the reaction, resulting in high costs.

[0004] For example, CN116598634A discloses a method for selectively separating and recovering metallic lithium from ternary cathode materials of waste lithium batteries. After mixing ternary cathode materials and carbon powder and calcining them at high temperature, water vapor is introduced. The unreacted carbon powder and water vapor generate reducing hydrogen and carbon monoxide at high temperature, and battery-grade lithium carbonate is also obtained.

[0005] For example, CN118099583A discloses a method for recycling and reusing waste nickel-cobalt-manganese lithium oxide batteries, including the following steps: pre-treating the waste nickel-cobalt-manganese lithium oxide batteries to recover the positive electrode material; calcining the positive electrode material, crushing and screening it to obtain nickel-cobalt-manganese lithium oxide powder; adding nickel source, cobalt source, manganese source and lithium source to the nickel-cobalt-manganese lithium oxide powder, mixing it evenly, and calcining it to obtain nickel-cobalt-manganese lithium oxide material; mixing the nickel-cobalt-manganese lithium oxide material and composite carbon material, grinding it, and calcining it to obtain nickel-cobalt-manganese lithium oxide material coated with carbon material; crushing, screening and demagnetizing the nickel-cobalt-manganese lithium oxide material coated with carbon material to obtain recycled nickel-cobalt-manganese lithium oxide material.

[0006] In summary, existing methods for recycling waste high-nickel ternary materials all have certain drawbacks. They require the use of external reagents or operate under harsh conditions, leading to high costs. Furthermore, the recycled materials often have low purity and poor electrochemical performance. Therefore, developing a novel method for recycling waste high-nickel ternary materials, as well as developing new recycled materials and batteries, is crucial. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for recycling waste high-nickel ternary materials, as well as a recycled material and a battery. This method utilizes the delithiation phase transition reaction of waste high-nickel ternary materials in a mixed atmosphere of CO2 and water vapor to achieve selective and efficient lithium extraction and enrichment, resulting in lithium-deficient materials that can be directly regenerated. The recycling method requires no external reagents or stringent conditions, offers carbon emission reduction benefits, achieves a lithium extraction rate of no less than 90%, and yields Li2CO3 with a purity greater than 99.5%. Furthermore, the recycled material prepared from the lithium-deficient material exhibits superior electrochemical performance.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for recycling waste high-nickel ternary materials, the recycling method comprising: Waste high-nickel ternary materials are placed in a mixed atmosphere containing CO2 and water vapor to carry out a delithiation phase transition reaction, yielding Li2CO3 and lithium-deficient materials.

[0009] In this invention, the waste high-nickel ternary materials include failed high-nickel ternary cathode materials (nickel content 60%~80%), specifically LiNi. 0.6 Co 0.2 Mn 0.2 O2 (NCM622), LiNi 0.7 Co 0.1 Mn 0.2 Materials such as O2 (NCM712).

[0010] Because medium- and high-nickel ternary materials undergo surface deterioration in environments containing CO2 and water vapor, generating Li2CO3 and lithium-deficient phases, this reaction is considered a "problem" and "failure mode" for cathode materials during storage and transportation. To ensure the storage effect of cathode materials, this reaction needs to be suppressed. In this invention, this reaction is creatively applied to the recycling process of waste medium- and high-nickel ternary materials.

[0011] In this invention, during the delithiation phase transition reaction, lithium in the waste high-nickel ternary material is extracted from the lattice in the form of Li2CO3 and deposited on the surface and pores of the product particles. At the same time, the waste high-nickel ternary material is reconstructed into a lithium-deficient material.

[0012] In this invention, the lithium removal phase transition reaction that occurs in waste high-nickel ternary materials in a mixed atmosphere containing CO2 and water vapor is utilized to achieve selective lithium removal and enrichment in the form of Li2CO3. At the same time, lithium-deficient materials that can be directly replenished and regenerated are obtained. The entire process does not require the addition of external reducing agents and acid-base reagents, high temperature and high pressure, or complex equipment, which significantly reduces energy consumption and cost, and realizes the green, low-carbon recycling and high-value regeneration of waste ternary materials.

[0013] In this invention, the lithium extraction rate of the recovery method is not less than 90%, and the purity of the obtained Li2CO3 is greater than 99.5%, which can be directly used for battery material production.

[0014] In this invention, the Li / Ni mixing degree of the recycled material obtained from the lithium-deficient material obtained by the recycling method is reduced from 6%~8% in the failed state to no more than 2.0% after lithium replenishment sintering. The first discharge capacity at 0.1C is restored to more than 98% of the initial material (before the use of waste high-nickel ternary materials). The capacity retention rate after 500 cycles at 1C is no less than 90%, which is better than conventional direct recycled materials.

[0015] In summary, this invention utilizes the delithiation phase transition reaction of waste high-nickel ternary materials in a mixed atmosphere of CO2 and water vapor to achieve selective and efficient extraction and enrichment of lithium, resulting in lithium-deficient materials that can be directly regenerated. The recycling method requires no external reagents or harsh conditions, has carbon emission reduction benefits, and achieves a lithium extraction rate of no less than 90%, with the obtained Li2CO3 having a purity greater than 99.5%. Furthermore, the regenerated materials prepared from lithium-deficient materials exhibit superior electrochemical performance.

[0016] Preferably, the lithium-deficient material comprises a composite phase material composed of a lithium-deficient spinel phase and a rock salt phase.

[0017] Preferably, the volume concentration of CO2 in the mixed atmosphere is not less than 10%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0018] Preferably, the relative humidity of the mixed atmosphere is 30% to 90%, for example, it can be 30%, 40%, 50%, 60%, 70%, 80% or 90%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the temperature of the mixed atmosphere is 20°C to 80°C, for example, it can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0020] Preferably, the pressure of the mixed atmosphere is 0.1MPa to 1MPa, for example, it can be 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa or 1.0MPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the mixed atmosphere comprises the atmosphere in a closed reactor.

[0022] Preferably, the time for the delithiation phase transition reaction is 1h to 24h, for example, it can be 1h, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, during the delithiation phase change reaction, the waste high-nickel ternary materials are intermittently crushed.

[0024] Preferably, during the lithium removal phase change reaction, the resulting waste high-nickel ternary material is crushed every 5 to 30 minutes.

[0025] In this invention, during the lithium removal phase change reaction, the obtained waste high-nickel ternary material is crushed every 5 to 30 minutes. For example, the crushing time can be 5 minutes, 8 minutes, 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, 22 minutes, 25 minutes, 28 minutes, or 30 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the pulverization method includes ball milling and / or pulverization using a pulverizer.

[0027] Preferably, before the delithiation phase change reaction, the waste medium-high nickel ternary material is pulverized to obtain waste medium-high nickel ternary material powder with a D50 particle size of 500nm~5μm.

[0028] In this invention, waste medium-high nickel ternary material powder with a D50 particle size of 500nm~5μm is obtained after pulverization before the delithiation phase change reaction. For example, it can be 500nm, 800nm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm or 5μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the recycling method further includes: washing the product obtained after the delithiation phase change reaction with water to obtain separated Li2CO3 and lithium-deficient material.

[0030] In this invention, the water washing utilizes the solubility of Li2CO3 in water to achieve efficient separation of Li2CO3 from lithium-deficient materials.

[0031] In this invention, after washing with water, a Li2CO3 washing solution and a residual solid are obtained; then methanol and / or ethanol are added to the obtained Li2CO3 washing solution to precipitate Li2CO3, and then solid-liquid separation and drying are performed sequentially to obtain Li2CO3; in addition, the obtained residual solid is dried to obtain a lithium-deficient material.

[0032] Preferably, the recycling method further includes: mixing the separated Li2CO3 with lithium-deficient materials and adjusting the molar ratio Li / Me, and then sintering in an oxygen-containing atmosphere to obtain a recycled high-nickel ternary material with a layered structure.

[0033] In this invention, the molar ratio Li / Me is the ratio of the molar amount of Li to the total molar amount of all transition metal elements in the mixture of Li2CO3, lithium-deficient materials, and lithium replenishing agents.

[0034] Preferably, during the sintering process, the reaction exhaust gas generated is condensed and dehydrated before being returned to the reactor for recycling.

[0035] Preferably, the oxygen concentration in the oxygen-containing atmosphere is not less than 20%, for example, it can be 20%, 22%, 25%, 28%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0036] Preferably, the sintering temperature is 600℃~850℃ and the time is 4h~12h.

[0037] In this invention, the sintering temperature is 600℃~850℃, for example, it can be 600℃, 620℃, 640℃, 660℃, 680℃, 700℃, 720℃, 740℃, 760℃, 780℃, 800℃, 820℃, 840℃ or 850℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] In this invention, the sintering time is 4h to 12h, for example, it can be 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h or 12h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Secondly, the present invention provides a recycled material, which is obtained by the recycling method described in the first aspect.

[0040] Preferably, the recycled material includes Li2CO3 and lithium-deficient materials.

[0041] Preferably, the recycled material comprises a recycled medium-high nickel ternary material with a layered structure prepared from Li2CO3 and lithium-deficient materials.

[0042] Thirdly, the present invention provides a battery comprising the recycled material described in the second aspect.

[0043] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0044] Compared with the prior art, the present invention has the following beneficial effects: (1) In this invention, the lithium removal phase transition reaction of waste high-nickel ternary materials in a mixed atmosphere containing CO2 and water vapor is utilized to achieve selective lithium removal and enrichment in the form of Li2CO3. At the same time, lithium-deficient materials that can be directly replenished and regenerated are obtained. The entire process does not require the addition of external reducing agents and acid-base reagents, high temperature and high pressure, or complex equipment, which significantly reduces energy consumption and cost, and realizes green and low-carbon recycling and high-value regeneration of waste ternary materials.

[0045] (2) In this invention, the lithium extraction rate of the recovery method is not less than 90%, and the purity of the obtained Li2CO3 is greater than 99.5%, which can be directly used for battery material production.

[0046] (3) In this invention, the Li / Ni mixing degree of the recycled material obtained by the lithium-deficient material obtained by the recycling method is reduced from 6%~8% in the failure state to no more than 2.0%, the first discharge capacity at 0.1C is restored to more than 98% of the initial material (the waste high-nickel ternary material before use), and the capacity retention rate after 500 cycles at 1C is no less than 90%, which is better than conventional direct recycled materials.

[0047] (4) In this invention, lithium selective and efficient extraction and enrichment of lithium is achieved by utilizing the delithiation phase transition reaction of waste high-nickel ternary materials in a mixed atmosphere of CO2 and water vapor, and lithium-deficient materials that can be directly replenished and regenerated are obtained. The recycling method does not require external reagents or harsh conditions, has carbon emission reduction benefits, and the lithium extraction rate is not less than 90%. The purity of the obtained Li2CO3 is greater than 99.5%, and the electrochemical performance of the regenerated materials prepared from lithium-deficient materials is better. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0049] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0050] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0051] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0052] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0053] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0054] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0055] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0056] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0057] Example 1 This embodiment provides a method for recycling waste high-nickel ternary materials, the recycling method comprising: (1) Waste high-nickel ternary material (NCM622 cathode material from the dismantling of retired electric vehicle batteries, ICP analysis showed a molar ratio of Li / Me of 0.91, a mixing degree of 6.5%, a D50 of 10.2 μm, and the initial 0.1C discharge capacity of the initial material before use was 167.3 mAh / g) was placed in a mixed atmosphere containing CO2 and water vapor and subjected to a delithiation phase transition reaction for 6 h. Lithium in the waste high-nickel ternary material was extracted from the lattice in the form of Li2CO3 and deposited on the surface and pores of the product particles. At the same time, the waste high-nickel ternary material was reconstructed into a lithium-deficient material, and a dark brown delithiation phase transition reaction product was obtained. The delithiation phase transition reaction product includes a lithium-deficient material (a composite phase material composed of lithium-deficient spinel phase and rock salt phase) with Li2CO3 loaded on the surface and in the pores. The mixed atmosphere has a CO2 volume concentration of 20%, a relative humidity of 80%, a temperature of 60°C, and an air pressure of 0.5 MPa. During the lithium removal phase change reaction, the obtained waste high-nickel ternary material is ball-milled for 10 minutes every 30 minutes. (2) The delithiation phase change reaction product obtained in step (1) is washed with water. Taking advantage of the solubility of Li2CO3 in water, Li2CO3 is dissolved in water to obtain Li2CO3 solution and residual solid. Then methanol is added to the obtained Li2CO3 washing solution to precipitate Li2CO3. After solid-liquid separation and drying are performed in sequence, Li2CO3 is obtained. In addition, the obtained residual solid is dried to obtain lithium-deficient material. (3) Mix the Li2CO3 obtained in step (2) with the lithium-deficient material, and adjust the molar ratio Li / Me to 1.05 by adding commercial LiOH. Then, sinter the mixture at 750°C for 8 hours in an oxygen-containing atmosphere with an oxygen concentration of 40% to obtain a recycled high-nickel ternary material with a layered structure.

[0058] Example 2 This embodiment provides a method for recycling waste high-nickel ternary materials, the recycling method comprising: (1) Waste high-nickel ternary materials (NCM622 cathode material from the dismantling of retired electric vehicle batteries, ICP analysis showed a molar ratio of Li / Me of 0.91, a mixing degree of 6.5%, a D50 of 10.2 μm, and the initial 0.1C discharge capacity of the initial material before use was 167.3 mAh / g) were placed in a mixed atmosphere containing CO2 and water vapor and subjected to a delithiation phase transition reaction for 5 h. Lithium in the waste high-nickel ternary materials was extracted from the lattice in the form of Li2CO3 and deposited on the surface and pores of the product particles. At the same time, the waste high-nickel ternary materials were reconstructed into lithium-deficient materials to obtain delithiation phase transition reaction products. The delithiation phase transition reaction products include lithium-deficient materials (a composite phase material composed of lithium-deficient spinel phase and rock salt phase) with Li2CO3 loaded on the surface and in the pores. The volume concentration of CO2 in the mixed atmosphere is 15%, the relative humidity is 85%, the temperature is 80℃, and the pressure is 1MPa. During the lithium removal phase change reaction, the obtained waste high-nickel ternary material is ball-milled for 3 minutes every 10 minutes. (2) The delithiation phase change reaction product obtained in step (1) is washed with water. Taking advantage of the solubility of Li2CO3 in water, Li2CO3 is dissolved in water to obtain Li2CO3 solution and residual solid. Then methanol is added to the obtained Li2CO3 washing solution to precipitate Li2CO3. After solid-liquid separation and drying are performed in sequence, Li2CO3 is obtained. In addition, the obtained residual solid is dried to obtain lithium-deficient material. (3) Mix the Li2CO3 obtained in step (2) with the lithium-deficient material, and adjust the molar ratio Li / Me to 1.05 by adding commercial LiOH. Then, sinter the mixture at 850°C for 4 hours in an oxygen-containing atmosphere with an oxygen concentration of 20% to obtain a recycled high-nickel ternary material with a layered structure.

[0059] Example 3 This embodiment provides a method for recycling waste high-nickel ternary materials, the recycling method comprising: (1) Waste high-nickel ternary materials (NCM622 cathode material from the dismantling of retired electric vehicle batteries, ICP analysis showed a molar ratio of Li / Me of 0.91, a mixing degree of 6.5%, a D50 of 10.2 μm, and the initial 0.1C discharge capacity of the initial material before use was 167.3 mAh / g) were placed in a mixed atmosphere containing CO2 and water vapor and subjected to a lithium delithiation phase transition reaction for 24 h. Lithium in the waste high-nickel ternary materials was extracted from the lattice in the form of Li2CO3 and deposited on the surface and pores of the product particles. At the same time, the waste high-nickel ternary materials were reconstructed into lithium-deficient materials to obtain lithium delithiation phase transition reaction products. The lithium delithiation phase transition reaction products include lithium-deficient materials (a composite phase material composed of lithium-deficient spinel phase and rock salt phase) with Li2CO3 loaded on the surface and in the pores. The mixed atmosphere has a CO2 volume concentration of 10%, a relative humidity of 90%, a temperature of 20°C, and an air pressure of 0.1 MPa. Before the delithiation phase change reaction, the waste medium-high nickel ternary material was ball-milled to obtain waste medium-high nickel ternary material powder with a D50 particle size of 2.5μm. (2) The delithiation phase change reaction product obtained in step (1) is washed with water. Taking advantage of the solubility of Li2CO3 in water, Li2CO3 is dissolved in water to obtain Li2CO3 solution and residual solid. Ethanol is then added to the obtained Li2CO3 washing solution to precipitate Li2CO3. Solid-liquid separation and drying are then performed sequentially to obtain Li2CO3. In addition, the obtained residual solid is dried to obtain lithium-deficient material. (3) Mix the Li2CO3 obtained in step (2) with the lithium-deficient material, and adjust the molar ratio Li / Me to 1.05 by adding commercial LiOH. Then, sinter the mixture at 600°C for 12 hours in an oxygen-containing atmosphere with an oxygen concentration of 60% to obtain a recycled high-nickel ternary material with a layered structure.

[0060] Example 4 This embodiment provides a method for recycling waste high-nickel ternary materials. Except for the CO2 volume concentration of 6% in the mixed atmosphere described in step (1), the rest is the same as in Example 1.

[0061] Example 5 This embodiment provides a method for recycling waste high-nickel ternary materials. Except for the volume concentration of CO2 in the mixed atmosphere described in step (1) being 1%, the rest is the same as in Example 1.

[0062] Example 6 This embodiment provides a method for recycling waste high-nickel ternary materials. Except for the relative humidity of the mixed atmosphere in step (1) being 15%, the rest is the same as in embodiment 1.

[0063] Example 7 This embodiment provides a method for recycling waste high-nickel ternary materials. Except for the relative humidity of the mixed atmosphere in step (1) being 97%, the rest is the same as in embodiment 1.

[0064] Example 8 This embodiment provides a method for recycling waste high-nickel ternary materials. Except for omitting the step of "ball milling the obtained waste high-nickel ternary materials for 10 minutes every 30 minutes during the delithiation phase change reaction", the rest is the same as in Embodiment 1.

[0065] Example 9 This embodiment provides a method for recycling waste high-nickel ternary materials. Except for omitting the entire step (2), omitting the mixing step in step (3), and directly adding commercial LiOH to the delithiation phase change reaction product obtained in step (1) to adjust the molar ratio Li / Me before sintering, the rest is the same as in Example 1.

[0066] Comparative Example 1 This comparative example provides a method for recycling waste high-nickel ternary materials. Except for replacing the mixed atmosphere in step (1) with an atmosphere containing only CO2, the rest is the same as in Example 1.

[0067] Comparative Example 2 This comparative example provides a method for recycling waste high-nickel ternary materials. Except for replacing the mixed atmosphere in step (1) with an atmosphere containing only water vapor, the rest is the same as in Example 1.

[0068] Comparative Example 3 This comparative example provides a method for recycling waste high-nickel ternary materials, the recycling method comprising: ICP testing was performed on the waste high-nickel ternary materials to obtain the actual content ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder. Then, nickel nitrate, cobalt hydroxide, manganese carbonate and lithium hydroxide were added to the ternary waste fine powder to adjust the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder to 8:1:1:0.95. The mixture was stirred and mixed thoroughly for 4 hours to obtain the mixture. The obtained mixture is then sintered twice under an oxygen-rich atmosphere. The first sintering temperature is 500℃, the heating rate is 7℃ / min, and the holding time is 5 hours. After the first sintering, the temperature is raised to 850℃ for a second sintering at a heating rate of 3℃ / min and a holding time of 12 hours to obtain the sintered material. The obtained sintered material is then crushed, sieved, and demagnetized to obtain recycled high-nickel ternary material.

[0069] The Li2CO3 obtained after evaporation and crystallization in the recovery methods provided in the above examples and comparative examples was tested using an X-ray diffractometer. The purity of Li2CO3 is shown in Table 1.

[0070] During the recovery process using the recovery methods provided in the above embodiments and comparative examples, the mass of Li2CO3 obtained after evaporation and crystallization was tested, and the lithium extraction rate was calculated as shown in Table 1.

[0071] The lithium-deficient materials obtained after filtration and drying in the recovery methods provided in the above embodiments and comparative examples were tested using an ICP analyzer. The Li residual rate in the lithium-deficient materials is shown in Table 1.

[0072] The recycled high-nickel ternary materials obtained after sintering in the above embodiments and comparative examples were tested using an X-ray diffractometer. The structure of the recycled high-nickel ternary materials is shown in Table 2, and the degree of mixing is shown in Table 1.

[0073] The electrochemical performance of the recycled high-nickel ternary material obtained after sintering in the above embodiments and comparative examples was tested. The test method was as follows: the obtained recycled high-nickel ternary material was mixed with Super P conductive agent and polyvinylidene fluoride binder in a preset mass ratio to prepare a positive electrode sheet. A lithium metal sheet was used as the counter electrode. A CR2032 coin cell was assembled using a polypropylene microporous membrane and an electrolyte (a 1 mol / L LiPF6 solution, with the solvent including EC, DMC and EMC in a volume ratio of 1:1:1). Constant current charge-discharge tests were conducted at room temperature within a voltage range of 2.8V to 4.3V. First, the material was activated at a rate of 0.1C for 3 cycles, then the initial discharge capacity was tested at a rate of 0.1C, and finally, long-cycle performance tests were performed at a rate of 1C. The 0.1C discharge capacity and the capacity retention rate after 500 cycles at 1C are shown in Table 2. The 0.1C initial discharge capacity recovery rate of the recycled high-nickel ternary material (i.e., the ratio of the 0.1C initial discharge capacity of the recycled high-nickel ternary material to the 0.1C initial discharge capacity of the original material) was calculated and is shown in Table 2.

[0074] Table 1 Table 2 From Table 1 and Table 2, we can obtain: (1) The Li2CO3 obtained by recycling using the recycling methods provided in Examples 1 to 3 of this invention has high purity, high lithium extraction rate and low lithium residue rate; in addition, the Li / Ni mixing degree of the recycled high-nickel ternary material is reduced from 6% to 8% in the failed state to no more than 2.0%, the first discharge capacity at 0.1C is restored to more than 98% of the initial material (before the use of waste high-nickel ternary material), and the capacity retention rate after 500 cycles at 1C is no less than 90%; (2) By comparing Example 1 with Examples 4 and 5, it can be seen that when the volume concentration of CO2 in the mixed atmosphere is not less than 10%, the recovery method has a better recovery effect. This is because CO2 is the core reactant of the delithiation phase change reaction. When the concentration is less than 10%, the LiOH generated on the surface cannot be converted into Li2CO3 in time, and a dense passivation layer will be formed to block the reaction channel, resulting in a significant decrease in lithium extraction rate and incomplete reconstruction of the lithium-deficient structure. (3) A comparison of Example 1 with Examples 6 and 7 shows that, in this invention, when the relative humidity of the mixed atmosphere is 30% to 90%, the recovery method has a better recovery effect. This is because when the relative humidity is too low, H... + Insufficient supply and slow ion exchange reaction rate lead to lower lithium extraction efficiency and worse performance of high-nickel ternary materials in regeneration. When the relative humidity is too high, liquid water is easily generated, causing particle agglomeration and blockage of reaction mass transfer, which in turn leads to lower lithium extraction rate and worse performance of high-nickel ternary materials in regeneration. (4) By comparing Example 1 and Example 8, it can be seen that in the present invention, during the delithiation phase change reaction, lithium in the surface layer of the waste high-nickel ternary material is extracted from the lattice in the form of Li2CO3 and deposited on the surface and pores of the product particles. At the same time, the surface layer of the waste high-nickel ternary material is reconstructed into a lithium-deficient material. Therefore, during the delithiation phase change reaction, the waste high-nickel ternary material is intermittently crushed, or the waste high-nickel ternary material is crushed before the delithiation phase change reaction to obtain waste high-nickel ternary material powder with a D50 particle size of 500nm~5μm, which can achieve full recycling of waste high-nickel ternary material. (5) By comparing Example 1 and Example 9, it can be seen that in this invention, after washing the delithiation phase change reaction with water, Li2CO3 washing liquid and residual solid are obtained. Then, methanol and / or ethanol are introduced into the Li2CO3 washing liquid to precipitate Li2CO3 from the washing liquid. The residual solid is dried to obtain separated Li2CO3 and lithium-deficient material. The separated Li2CO3 and lithium-deficient material are mixed and the molar ratio Li / Me is adjusted. Then, sintering is carried out in an oxygen-containing atmosphere to obtain a regenerated medium-high nickel ternary material with a layered structure. This can obtain a regenerated medium-high nickel ternary material with better performance. This is because the Li / Me molar ratio can be precisely controlled by separating and then adding lithium during sintering, avoiding local lithium excess or deficiency. At the same time, reaction byproducts are removed, making element diffusion more uniform during sintering, effectively suppressing Li / Ni mixing, thereby significantly improving the electrochemical performance of the regenerated medium-high nickel ternary material. (6) By comparing Example 1 with Comparative Examples 1 to 3, it can be seen that in this invention, the lithium removal phase change reaction of waste high-nickel ternary materials in a mixed atmosphere containing CO2 and water vapor is utilized to achieve selective lithium removal and enrichment in the form of Li2CO3. At the same time, lithium-deficient materials that can be directly replenished and regenerated are obtained. The whole process does not require the addition of external reducing agents and acid-base reagents, high temperature and high pressure, or complex equipment, which significantly reduces energy consumption and cost, and realizes the green and low-carbon recycling and high-value regeneration of waste ternary materials. In this invention, the lithium extraction rate of the recovery method is not less than 90%, and the purity of the obtained Li2CO3 is greater than 99.5%, which can be directly used for battery material production.

[0075] In this invention, the Li / Ni mixing degree of the recycled material obtained from the lithium-deficient material obtained by the recycling method is reduced from 6%~8% in the failed state to no more than 2.0% after lithium replenishment sintering. The first discharge capacity at 0.1C is restored to more than 98% of the initial material (before the use of waste high-nickel ternary materials). The capacity retention rate after 500 cycles at 1C is no less than 90%, which is better than conventional direct recycled materials.

[0076] In summary, this invention utilizes the delithiation phase transition reaction of waste high-nickel ternary materials in a mixed atmosphere of CO2 and water vapor to achieve selective and efficient extraction and enrichment of lithium, resulting in lithium-deficient materials that can be directly regenerated. The recycling method requires no external reagents or harsh conditions, has carbon emission reduction benefits, and achieves a lithium extraction rate of no less than 90%, with the obtained Li2CO3 having a purity greater than 99.5%. Furthermore, the regenerated materials prepared from lithium-deficient materials exhibit superior electrochemical performance.

[0077] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for recycling waste high-nickel ternary materials, characterized in that, The recycling method includes: Waste high-nickel ternary materials are placed in a mixed atmosphere containing CO2 and water vapor to carry out a delithiation phase transition reaction, yielding Li2CO3 and lithium-deficient materials.

2. The recycling method according to claim 1, characterized in that, The lithium-deficient material includes a composite phase material composed of lithium-deficient spinel phase and rock salt phase.

3. The recycling method according to claim 1, characterized in that, The volume concentration of CO2 in the mixed atmosphere is not less than 10%; And / or, the relative humidity of the mixed atmosphere is 30%~90%; And / or, the temperature of the mixed atmosphere is 20°C to 80°C; And / or, the pressure of the mixed atmosphere is 0.1 MPa to 1 MPa; And / or, the time for the delithiation phase transition reaction is 1h to 24h.

4. The recycling method according to claim 1, characterized in that, During the delithiation phase change reaction, the waste high-nickel ternary materials are intermittently crushed. And / or, before the delithiation phase change reaction, the waste medium-high nickel ternary material is pulverized to obtain waste medium-high nickel ternary material powder with a D50 particle size of 500nm~5μm.

5. The recycling method according to claim 1, characterized in that, The recycling method further includes washing the product obtained after the delithiation phase change reaction with water to obtain separated Li2CO3 and lithium-deficient material.

6. The recycling method according to claim 5, characterized in that, The recycling method further includes: mixing the separated Li2CO3 with lithium-deficient materials and adjusting the molar ratio Li / Me, and then sintering in an oxygen-containing atmosphere to obtain a recycled high-nickel ternary material with a layered structure. Preferably, during the sintering process, the reaction exhaust gas generated is condensed and dehydrated before being returned to the reactor for recycling.

7. The recycling method according to claim 6, characterized in that, In the oxygen-containing atmosphere, the oxygen concentration is not less than 20%; And / or, the sintering temperature is 600℃~850℃, and the time is 4h~12h.

8. A recycled material, characterized in that, The recycled material is obtained by the recycling method according to any one of claims 1 to 7.

9. The recycled material according to claim 8, characterized in that, The recycled materials include Li2CO3 and lithium-deficient materials; And / or, the recycled material includes recycled medium-high nickel ternary materials with a layered structure prepared from Li2CO3 and lithium-deficient materials.

10. A battery, characterized in that, The battery comprises the recycled material as described in claim 9.

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