Method for recovering ternary positive electrode material, positive electrode material, secondary battery, and electric device

Abstract

The invention provides a recovery method of a ternary positive electrode material, a positive electrode material, a secondary battery and a power utilization device, and the recovery method of the ternary positive electrode material comprises the following steps: 1, mixing a to-be-recovered material of the ternary positive electrode material, an organic solvent and a dispersant, and stirring and dispersing at 25-100 DEG C for 0.2-2 h to obtain a dispersion liquid; step 2, standing and settling the dispersion liquid at 25-100 DEG C for 0.5-10 hours, carrying out solid-liquid separation, and taking a lower-layer solid phase, so as to obtain an intermediate material; and 3, replacing the to-be-recycled ternary positive electrode material in the step 1 with the intermediate material, and repeating the step 1 and the step 2 for more than two times to obtain the recycled ternary positive electrode material. According to the recovery method of the ternary positive electrode material, the conductive agent in the to-be-recovered material of the ternary positive electrode material can be effectively removed, and the performance of the recovered and repaired ternary positive electrode material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of secondary batteries, and in particular to a method for recycling ternary positive electrode materials, positive electrode materials, secondary batteries and electrical devices. Background Art

[0002] In recent years, with the rapid development of secondary battery technology, secondary batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as in many fields such as electric tools, electric bicycles, electric motorcycles and electric vehicles. Nickel-cobalt-manganese ternary positive electrode materials have the advantages of high energy density, good rate performance and long cycle life, and are widely used as positive electrode active materials in secondary batteries.

[0003] With the extensive application of secondary batteries, the recycling of waste secondary batteries has become an urgent problem to be solved. Ternary cathode materials are the main valuable components in waste secondary batteries. Therefore, how to remove impurities in the ternary cathode materials to be recycled, effectively recycle the ternary cathode materials in waste secondary batteries, and realize the resource utilization of ternary cathode materials has become one of the important research directions in this field. Summary of the invention

[0004] The present application is made in view of the above-mentioned problems, and one of its purposes is to provide a method for recycling ternary positive electrode materials with good impurity removal effect and capable of effectively separating the conductive agent in the material to be recycled, and correspondingly provides a positive electrode material, a secondary battery and an electrical device.

[0005] In order to achieve the above object, the first aspect of the present application provides a method for recycling a ternary positive electrode material, comprising the following steps:

[0006] Step 1: Mix the ternary cathode material to be recycled, the organic solvent and the dispersant, and stir and disperse at 25°C to 100°C for 0.2h to 2h to obtain a dispersion;

[0007] Step 2: allowing the dispersion to settle at 25°C to 100°C for 0.5h to 10h, separating the solid and liquid, and taking the lower solid phase to obtain an intermediate material;

[0008] Step three: using the intermediate material to replace the ternary positive electrode material to be recycled in step one and repeating step one and step two more than twice to obtain a recycled ternary positive electrode material.

[0009] The above-mentioned recycling method is to mix the ternary positive electrode material to be recycled with an organic solvent and a dispersant, and then stir and disperse it at 25°C to 100°C for 0.2h to 2h. At this temperature, the binder in the ternary positive electrode material to be recycled can be fully dissolved in the organic solvent, which is not only conducive to removing the binder, but also can alleviate or avoid the influence of the binder on the separation of the conductive agent, thereby improving the separation and removal effect of the conductive agent. By adding a dispersant to the dispersion, the dispersant interacts with the conductive agent, and the conductive agent can be better suspended in the upper layer of the dispersion during the subsequent static sedimentation process, thereby improving the separation effect of the conductive agent.

[0010] By allowing the dispersion to settle at 25°C to 100°C for 0.5h to 10h, due to the different densities and particle sizes of the conductive agent and the ternary positive electrode material, the sedimentation speeds in the solvent are different. After the static sedimentation, the ternary positive electrode material will settle to the lower layer of the dispersion, while the conductive agent will be suspended in the upper layer of the dispersion, thereby achieving the separation of the conductive agent and the ternary positive electrode material; static sedimentation controlled at the above temperature can maintain the dissolution of the binder in the organic solvent, avoid the precipitation of the binder and affect the separation effect of the binder and the conductive agent. By repeating the above stirring, dispersing and static sedimentation steps more than twice, the binder and conductive agent in the ternary positive electrode material to be recycled can be effectively removed, and the performance of the ternary positive electrode material after recycling and repair can be improved.

[0011] In any embodiment, the stirring and dispersing temperature is 70° C. to 100° C. In this way, the binder can be better kept dissolved in the organic solvent during the stirring and dispersing process, which is more conducive to improving the separation and removal effect of the binder and the conductive agent in the ternary positive electrode material to be recycled.

[0012] In any embodiment, the temperature of the static sedimentation is 70° C. to 100° C. In this way, the binder can be better kept dissolved in the organic solvent during the static sedimentation process, which is more conducive to improving the separation and removal effect of the binder and the conductive agent in the ternary positive electrode material to be recycled.

[0013] In any embodiment, in step 3, the intermediate material is used to replace the ternary positive electrode material to be recycled in step 1, and step 1 and step 2 are repeated 3 to 8 times. In this way, while maintaining a good separation effect on the binder and the conductive agent, it is beneficial to control the agent consumption, production cost and efficiency.

[0014] In any embodiment, the stirring and dispersing speed is 500 r / min to 2000 r / min. This is conducive to fully dispersing the binder and the conductive agent in the ternary positive electrode material to be recycled from the ternary positive electrode material, and is conducive to improving the separation and removal effect of the binder and the conductive agent.

[0015] In any embodiment, the solid-liquid mass ratio of the ternary cathode material to be recycled to the organic solvent is 1:(1-10). This is conducive to fully dissolving the binder in the ternary cathode material to be recycled, and fully dispersing the ternary cathode material, the binder and the conductive agent in the organic solvent, which is conducive to improving the separation and removal effect of the binder and the conductive agent.

[0016] In any embodiment, the dispersant includes one or more of carbon black dispersant K-560, organosilicon dispersant K-574 and Anjeka6830 lithium battery slurry dispersant. In this way, the conductive agent is better suspended in the upper layer of the dispersion in the static sedimentation step, which is beneficial to further improve the separation effect of the ternary positive electrode material and the conductive agent.

[0017] In any embodiment, the amount of the dispersant added to the dispersion is 0.01% to 2% of the mass of the ternary cathode material to be recycled, which is more conducive to improving the separation effect of the ternary cathode material and the conductive agent.

[0018] In any embodiment, the organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetraethylpyrrolidone and dimethyl sulfoxide. In this way, the binder in the ternary cathode material to be recycled can be effectively dissolved.

[0019] In any embodiment, the ternary positive electrode material to be recycled includes a ternary positive electrode material, a binder and a conductive agent.

[0020] In any embodiment, after step three, the method further includes filtering, washing and drying the recovered ternary positive electrode material.

[0021] The second aspect of the present application provides a ternary positive electrode material, which is recovered by the ternary positive electrode material recovery method of the first aspect of the present application. The recovered ternary positive electrode material has a low content of binder and conductive agent, and is used as a repair raw material. After lithium supplementation and repair, a ternary positive electrode material with good electrochemical performance can be obtained.

[0022] The third aspect of the present application provides a secondary battery, comprising a positive electrode plate, wherein the positive electrode plate comprises a positive electrode film layer, wherein the positive electrode film layer comprises a ternary positive electrode material obtained by lithium supplementation and repair of the ternary positive electrode material of the second aspect of the present application. The secondary battery has a high cycle capacity retention rate and a low cost.

[0023] A fourth aspect of the present application provides an electrical device, comprising the secondary battery of the third aspect of the present application.

[0024] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to better describe and illustrate the embodiments or examples provided by the present application, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of the disclosed application, the embodiments or examples currently described, and any of the best modes of these applications currently understood. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0026] Figure 1 A schematic diagram of a battery cell according to an embodiment of the present application;

[0027] Figure 2 for Figure 1 An exploded view of a battery cell according to an embodiment of the present application is shown;

[0028] Figure 3 A schematic diagram of an electrical device using a secondary battery according to an embodiment of the present application as a power source.

[0029] Description of reference numerals:

[0030] 5. Battery cell; 51. Shell; 52. Electrode assembly; 53. Cover plate; 6. Electrical device. DETAILED DESCRIPTION

[0031] Hereinafter, the recovery method of the ternary positive electrode material, the ternary positive electrode material, the secondary battery and the implementation mode of the electric device of the present application are described in detail with appropriate reference to the drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0032] The "range" disclosed in the present application can be limited in the form of a lower limit and an upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The range limited in this way can be including or excluding end values, and any end value can be included or not included independently, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a specific parameter, it is understood that the range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are also listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents the abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to listing the parameter as, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0033] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0034] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments. The "implementation methods" mentioned herein have a similar understanding.

[0036] Those skilled in the art will appreciate that, in the methods of each embodiment or example, the order in which each step is written does not mean a strict order of execution and does not constitute any limitation on the implementation process, and the detailed order of execution of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0037] In the present application, in the open technical features or technical solutions described by the words "contain", "include", "comprise", etc., unless otherwise specified, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3. Unless otherwise specified, it may also include other members or may not include additional members. It can be regarded as providing both the feature or solution of "A consists of a1, a2 and a3" and the feature or solution of "A not only includes a1, a2 and a3, but also includes other members". In the present application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0038] In this application, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel schemes of "yes" or "no". If there are multiple "options" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "option" is independent.

[0039] With the extensive application of secondary batteries, the recycling of waste secondary batteries has become an urgent problem to be solved. Ternary cathode materials are the main valuable components in waste secondary batteries. Therefore, how to remove impurities in the ternary cathode materials to be recycled, effectively recycle the ternary cathode materials in waste secondary batteries, and realize the resource utilization of ternary cathode materials has become one of the important research directions in this field.

[0040] In this regard, an embodiment of the present application provides a method for recycling a ternary positive electrode material, which includes the following steps: step one, mixing the ternary positive electrode material to be recycled, an organic solvent and a dispersant, and stirring and dispersing them at 25°C~100°C for 0.2h~2h to obtain a dispersion; step two, allowing the above dispersion to stand and settle at 25°C~100°C for 0.5h~10h, and then performing solid-liquid separation to remove the lower solid phase to obtain an intermediate material; step three, using the above intermediate material to replace the ternary positive electrode material to be recycled in step one and repeating steps one and two more than twice to obtain a recovered ternary positive electrode material.

[0041] For the recovery of positive electrode active materials in waste secondary batteries, traditional technology usually adopts high-temperature pyrolysis, which decomposes impurities such as conductive carbon in the recycled materials through high-temperature smelting to separate metal and non-metal materials in the battery. This method not only consumes a lot of energy, but also causes the loss of valuable components and produces toxic and harmful gases; moreover, the ternary positive electrode materials obtained by pyrolysis will be reduced by conductive carbon at high temperature, resulting in a large number of irreparable cracks and rock salt phases, causing irreversible damage to the structure of the ternary positive electrode materials, resulting in a significant reduction in the discharge performance and cycle life of the recovered and repaired ternary positive electrode materials, which cannot meet commercial requirements.

[0042] The above-mentioned method for recycling the ternary positive electrode material of the present application is as follows: first, the ternary positive electrode material to be recycled is mixed with an organic solvent and a dispersant, and then the mixture is stirred and dispersed at 25°C~100°C for 0.2h~2h, and then the dispersion is allowed to stand and settle at 25°C~100°C for 0.5h~10h. After solid-liquid separation, the lower solid phase replaces the ternary positive electrode material to be recycled and the above-mentioned stirring, dispersing and standing sedimentation steps are repeated more than twice to obtain the recycled ternary positive electrode material.

[0043] The above-mentioned recycling method is to mix the ternary positive electrode material to be recycled with an organic solvent and a dispersant, and then stir and disperse it at 25°C to 100°C for 0.2h to 2h. At this temperature, the binder in the ternary positive electrode material to be recycled can be fully dissolved in the organic solvent, which is not only conducive to removing the binder, but also can alleviate or avoid the influence of the binder on the separation of the conductive agent, thereby improving the separation and removal effect of the conductive agent. By adding a dispersant to the dispersion, the dispersant interacts with the conductive agent, and the conductive agent can be better suspended in the upper layer of the dispersion during the subsequent static sedimentation process, thereby improving the separation effect of the conductive agent.

[0044] By allowing the dispersion to settle at 25°C to 100°C for 0.5h to 10h, due to the different densities and particle sizes of the conductive agent and the ternary positive electrode material, the sedimentation speeds in the solvent are different. After the static sedimentation, the ternary positive electrode material will settle to the lower layer of the dispersion, while the conductive agent will be suspended in the upper layer of the dispersion, thereby achieving the separation of the conductive agent and the ternary positive electrode material; static sedimentation controlled at the above temperature can maintain the dissolution of the binder in the organic solvent, avoid the precipitation of the binder and affect the separation effect of the binder and the conductive agent. By repeating the above stirring, dispersing and static sedimentation steps more than twice, the binder and conductive agent in the ternary positive electrode material to be recycled can be effectively removed, and the performance of the ternary positive electrode material after recycling and repair can be improved.

[0045] It should be noted that the ternary cathode material to be recycled refers to the material obtained by disassembling the cathode electrode sheet from the waste secondary battery and separating the cathode film layer from the cathode current collector in the cathode electrode sheet. In addition to the ternary cathode material, the ternary cathode material to be recycled usually also includes a binder and a conductive agent, wherein the binder is usually an organic polymer, such as PVDF (polyvinylidene fluoride), etc., and the conductive agent is usually conductive carbon. Generally, LiNi 0.8 Co 0.1 Mn 0.1 Taking O2 ternary cathode material as an example, the D50 particle size of its single crystal particles is usually 3μm~4μm, and the true density is usually 5.5g / cm 3 The D50 particle size of conductive carbon is usually between 0.01μm and 0.1μm, and the true density is usually 1.8g / cm 3 There are large differences in the particle size and density of the ternary positive electrode material and the conductive agent.

[0046] It can be understood that the temperatures for stirring and dispersing and for settling can be independently 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C and any value within the range formed by any two of the above values; the time for stirring and dispersing can be 0.2h, 0.3h, 0.4h, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.1h, 1.2h, The time for static sedimentation can be 0.5h, 0.8h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h and any value within the range formed by any two of the above values.

[0047] Optionally, the temperature for stirring and dispersing is 70°C to 100°C; the temperature for static sedimentation is 70°C to 100°C. Controlling the temperature for stirring and dispersing and static sedimentation within the above temperature range can better maintain the dissolution of the binder in the organic solvent, which is more conducive to improving the separation and removal effect of the binder and the conductive agent in the ternary positive electrode material to be recycled.

[0048] In any embodiment, in step three, the intermediate material is used to replace the ternary positive electrode material to be recycled in step one and step one and step two are repeated 3 to 8 times. Appropriately increasing the number of repetitions of stirring and dispersing and standing and settling can improve the separation and removal effect of the binder and the conductive agent. When the repetition reaches a certain number of times, the gain effect of separation and impurity removal is not obvious, but it will significantly increase the consumption of the agent, increase the production cost, and reduce the production efficiency. By controlling the number of repetitions of stirring and dispersing and standing and settling to 3 to 8 times, while maintaining a good separation effect on the binder and the conductive agent, it is beneficial to control the agent consumption, production cost and efficiency.

[0049] In any embodiment, the stirring and dispersing speed is 500r / min~2000r / min. Controlling the stirring and dispersing speed within the above range is conducive to fully dispersing the binder and the conductive agent in the ternary positive electrode material to be recycled from the ternary positive electrode material, which is conducive to improving the separation and removal effect of the binder and the conductive agent.

[0050] It can be understood that the rotation speed of stirring and dispersing can be 500r / min, 600r / min, 700r / min, 800r / min, 900r / min, 1000r / min, 1100r / min, 1200r / min, 1300r / min, 1400r / min, 1500r / min, 1600r / min, 1700r / min, 1800r / min, 1900r / min, 2000r / min and any value within the range formed by any two of the above values.

[0051] In any embodiment, the solid-liquid mass volume ratio of the ternary positive electrode material to be recycled and the organic solvent is 1g: (1mL~10mL). Controlling the solid-liquid mass ratio of the ternary positive electrode material to be recycled and the organic solvent within the above range is conducive to fully dissolving the binder in the ternary positive electrode material to be recycled, and fully dispersing the ternary positive electrode material, the binder and the conductive agent in the organic solvent, which is conducive to improving the separation and removal effect of the binder and the conductive agent.

[0052] It can be understood that the solid-liquid mass volume ratio of the ternary positive electrode material to be recycled and the organic solvent can be 1g:1mL, 1g:2mL, 1g:3mL, 1g:4mL, 1g:5mL, 1g:6mL, 1g:7mL, 1g:8mL, 1g:9mL, 1g:10mL and any ratio within the range formed by any two of the above ratios.

[0053] In any embodiment, the dispersant includes one or more of carbon black dispersant K-560, organosilicon dispersant K-574 and Anjeka6830 lithium battery slurry dispersant. The use of the above-mentioned types of dispersants in the dispersion can form a good combination with the conductive agent, which is conducive to better suspending the conductive agent in the upper layer of the dispersion in the static sedimentation step, while the ternary positive electrode material is settled in the lower layer of the dispersion, thereby further improving the separation effect of the ternary positive electrode material and the conductive agent.

[0054] In any embodiment, the amount of the dispersant added to the dispersion is 0.01% to 2% of the mass of the ternary cathode material to be recycled. Controlling the amount of the dispersant added within the above range is more conducive to improving the separation effect of the ternary cathode material and the conductive agent.

[0055] It can be understood that the amount of dispersant added can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0% of the mass of the ternary positive electrode material to be recycled, and any value within the range formed by any two of the above values.

[0056] In any embodiment, the organic solvent includes one or more of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), tetraethylpyrrolidone (NEP) and dimethyl sulfoxide (DMSO). The above organic solvents can effectively dissolve the binder in the ternary cathode material to be recycled.

[0057] In any embodiment, after the number of repeated stirring, dispersing and static sedimentation in step three is completed, the recovery method further includes the steps of filter pressing, washing and drying the recovered ternary positive electrode material. The organic solvent in the recovered ternary positive electrode material can be removed by filter pressing; the water-soluble impurities in the recovered ternary positive electrode material can be further removed by washing, wherein the washing solvent can be deionized water; after drying, a dry raw material for the ternary positive electrode material to be repaired can be obtained. Subsequently, the recovered ternary positive electrode material can be used as the raw material to be repaired for lithium supplementation to obtain the repaired ternary positive electrode material, which is used as the positive electrode active material in the positive electrode sheet of the secondary battery.

[0058] The second aspect of the present application provides a ternary positive electrode material, which is recovered by the ternary positive electrode material recovery method of the first aspect of the present application. The recovered ternary positive electrode material has a low content of binder and conductive agent, and is used as a repair raw material. After lithium supplementation and repair, a ternary positive electrode material with good electrochemical performance can be obtained.

[0059] The third aspect of the present application provides a secondary battery, the secondary battery includes a positive electrode plate, the positive electrode plate includes a positive electrode film layer, the positive electrode film layer includes a ternary positive electrode material obtained by repairing the ternary positive electrode material of the second aspect of the present application after lithium supplementation. The secondary battery of the present application adopts the ternary positive electrode material obtained by the recycling method of the present application and the ternary positive electrode material formed by the lithium supplementation repair, the secondary battery has a high cycle capacity retention rate, and its cost is lower than that of a secondary battery using fresh ternary positive electrode material.

[0060] In some of the embodiments, the ternary positive electrode material recovered by the recycling method of the first aspect of the present application is used as a repair raw material, and the ratio of the repair raw material to the lithium source is determined according to the ratio of each element in the ternary positive electrode material and the element ratio of the ternary positive electrode material required after repair. The repair raw material and the lithium source are mixed and solid-phase sintered to obtain the ternary positive electrode material after lithium supplementation and repair.

[0061] A fourth aspect of the present application provides an electrical device, which includes the secondary battery of the third aspect of the present application.

[0062] The secondary battery and the electric device of the present application will be described below with reference to the drawings as appropriate.

[0063] Unless otherwise specified, the components, material types or contents of the batteries mentioned are applicable to both lithium-ion secondary batteries and sodium-ion secondary batteries.

[0064] In one embodiment of the present application, a secondary battery is provided.

[0065] Generally, a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0066] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0067] As a non-limiting example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0068] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be obtained by forming a metal material on a polymer material substrate. In the positive electrode current collector, non-limiting examples of the metal material may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the positive electrode current collector, non-limiting examples of the polymer material substrate may include one or more of substrates such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0069] In some embodiments, the positive electrode active material is recovered by the recovery method of the present application and is repaired by lithium supplementation to form a ternary positive electrode material.

[0070] In some embodiments, the positive electrode active material layer may also optionally include a binder. As a non-limiting example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. The weight ratio of the binder in the positive electrode active material layer is 0 wt % to 20 wt %, based on the total weight of the positive electrode active material layer.

[0071] In some embodiments, the positive electrode active material layer may further include a conductive agent. As a non-limiting example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The weight ratio of the conductive agent in the positive electrode active material layer is 0 wt % to 20 wt %, based on the total weight of the positive electrode active material layer.

[0072] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry, wherein the positive electrode slurry has a solid content of 40wt% to 80wt%, and the viscosity at room temperature is adjusted to 5000mPa·s to 25000mPa·s, and the positive electrode slurry is coated on both sides of the positive electrode collector, and after drying, the positive electrode sheet is formed by cold rolling; the unit surface density of the positive electrode powder coated on both sides is 150g / m 2 ~350g / m 2 The compaction density of the positive electrode is 3.0g / cm 3 ~3.6g / cm 3 , optional 3.3g / cm 3 ~3.5g / cm 3 .

[0073] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer includes a negative electrode active material.

[0074] As a non-limiting example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0075] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be obtained by forming a metal material on a polymer material substrate. Among them, in the negative electrode current collector, non-limiting examples of the metal material may include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the negative electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0076] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery known in the art.

[0077] As a non-limiting example, the negative electrode active material of the secondary battery may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0078] In some embodiments, the negative electrode active material layer may further include a binder. The binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0079] In some embodiments, the negative electrode active material layer may further include a conductive agent, which may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0080] In some embodiments, the negative electrode active material layer may further optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0081] In some embodiments, the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (a non-limiting example of the solvent is deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on at least one side of the surface of the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained. The surface of the negative electrode collector coated with the negative electrode slurry can be a single surface of the negative electrode collector or on both surfaces of the negative electrode collector. The solid content of the negative electrode slurry can be 40wt%~60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000mPa·s~10000mPa·s. When coating the negative electrode slurry, the double-sided coating unit surface density based on dry weight (excluding solvent) can be 75g / m 2 ~220g / m 2 The compaction density of the negative electrode sheet can be 1.0g / cm 3 ~1.8g / cm 3 .

[0082] The electrolyte has the function of conducting ions between the positive electrode and the negative electrode. The present application has no particular restrictions on the type of electrolyte, which can be selected according to needs. For example, the electrolyte can be liquid, gel or all-solid.

[0083] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0084] In some embodiments, the electrolyte salt of the secondary battery may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonyl imide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobisoxalatophosphate (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).

[0085] In some embodiments, the solvent may include one or more of fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), and diethyl sulfone (ESE).

[0086] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0087] In some embodiments, the additive in the electrolyte may include, but is not limited to, one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), trifluoromethylethylene carbonate (TFPC), and the like.

[0088] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.

[0089] In some embodiments, the material of the isolation membrane may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane may be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0090] In some embodiments, the thickness of the isolation film is 6 μm to 40 μm, and may be 12 μm to 20 μm.

[0091] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0092] In some embodiments, the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.

[0093] In some embodiments, the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and further, non-limiting examples of plastic may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0094] The secondary battery includes at least one battery cell. The secondary battery may include one or more battery cells.

[0095] In this application, unless otherwise specified, "battery cell" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and further, generally speaking, at least includes a positive electrode sheet, a negative electrode sheet and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0096] The present application has no particular limitation on the shape of the battery cell, which may be cylindrical, square or any other shape. Figure 1 The battery cell 5 is a square structure as an example.

[0097] In some embodiments, reference Figure 2, the outer packaging may include a shell 51 and a cover plate 53. Among them, the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0098] In some embodiments, the battery cells 5 can be assembled into a battery module. The number of battery cells 5 contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0099] In the battery module, the plurality of battery cells 5 may be arranged in sequence along the length direction of the battery module. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.

[0100] Optionally, the battery module may further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0101] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

[0102] The battery pack may include a battery box and a plurality of battery modules disposed in the battery box. The battery box includes an upper box body and a lower box body, and the upper box body can be covered on the lower box body to form a closed space for accommodating the battery modules. The plurality of battery modules can be arranged in the battery box in any manner.

[0103] In addition, the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. Electrical devices may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.

[0104] As an electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0105] Figure 3 The power consumption device 6 is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device's requirements for high power and high energy density of secondary batteries, a battery pack or a battery module can be used.

[0106] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.

[0107] The following are some examples.

[0108] In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer, the present application will be further described in detail below in conjunction with the embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its applications. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0109] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0110] Embodiment 1:

[0111] (1) Ternary cathode material recycling

[0112] (1.1) The ternary positive electrode material to be recycled removed from the positive electrode plate of the waste lithium-ion secondary battery is put into a high-speed disperser filled with an organic solvent. The organic solvent is NMP (N-methylpyrrolidone). The solid-liquid mass volume ratio of the recycled material to NMP is 1g:2mL. A dispersant carbon black dispersant K-560 is added at a mass ratio of 0.2% of the mass of the ternary positive electrode material to be recycled. The dispersion tank of the disperser is equipped with steam insulation. The high-speed disperser is turned on and stirred and dispersed at 70°C and a speed of 1500r / min for 1h to obtain a dispersion liquid. The ternary positive electrode material to be recycled contains lithium nickel cobalt manganese ternary positive electrode material, a binder PVDF and conductive carbon.

[0113] (1.2) The dispersion obtained in step (1.1) is transported to a scraper sedimentation tank for static sedimentation and stratification treatment. The static sedimentation time is 4 hours and the temperature is kept at 70°C. After the upper layer of the conductive carbon-rich solution is extracted after sedimentation, the lower layer of the ternary positive electrode material slurry is scraped out after sedimentation to obtain an intermediate material.

[0114] (1.3) Substituting the intermediate material obtained in step (1.2) for the ternary positive electrode material to be recycled in step (1.1), and repeating the above steps (1.1) and (1.2) three times; conveying the ternary positive electrode material slurry obtained after completing the number of repetitions to a filter press, performing filter pressing and water washing treatment, and then drying to obtain a recycled ternary positive electrode material.

[0115] (2) Repair and lithium supplementation

[0116] The recovered ternary cathode material was mixed with lithium hydroxide (LiOH·H2O) in a mass ratio of 2:0.243, and the first sintering was carried out in a tube furnace under an oxygen atmosphere at 600°C for 6 hours, and the oxygen purity was greater than 99.99%; then the second sintering was carried out in a tube furnace under an oxygen atmosphere at 750°C for 9 hours, and the oxygen purity was greater than 99.99%. The ternary cathode material after lithium supplementation and repair was obtained, and the molecular formula was LiNi 0.8 Co 0.1 Mn 0.1 O2.

[0117] (3) Preparation of positive electrode

[0118] Fully dissolve 1.0wt% polyvinylidene fluoride (PVDF) binder in N-methylpyrrolidone, add 1.0wt% carbon black conductive agent and 98wt% NCM811 material after lithium repair in step (2) to make a uniformly dispersed slurry. Evenly apply the slurry on both sides of the aluminum foil current collector, transfer it to a vacuum drying oven for complete drying, roll the obtained pole piece, and then punch it to obtain the positive pole piece. The single side density of the positive electrode film layer is 248g / m 2 , compacted density is 3.45g / cm 3 .

[0119] (4) Preparation of negative electrode

[0120] The negative electrode active material graphite, conductive agent carbon black (Super P), binder styrene butadiene rubber (SBR), and carboxymethyl cellulose (CMC) are mixed evenly in a proper amount of solvent deionized water at a mass ratio of 96:1.5:1.5 to obtain a negative electrode slurry; the negative electrode slurry is coated on both sides of the negative electrode current collector copper foil, and a negative electrode active material layer is formed on both sides of the negative electrode current collector through drying and cold pressing, and finally a negative electrode sheet is obtained through striping and cutting processes. The single side density of the negative electrode film layer is 168 g / m 2 , compacted density is 1.7g / cm 3 .

[0121] (5) Isolation film

[0122] A polypropylene film with a thickness of 15 μm was used as the isolation film.

[0123] (6) Electrolyte

[0124] In an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), 1 mol / L lithium salt lithium hexafluorophosphate LiPF6 was dissolved in an organic solvent; the organic solvent was EC (ethylene carbonate) / DMC (dimethyl carbonate) / EMC (ethyl methyl carbonate) in a volume ratio of 1:1:1, and 10wt% FEC (fluoroethylene carbonate) and 2wt% VC (vinylene carbonate) were added as additives; after stirring evenly, an electrolyte was obtained.

[0125] (7) Battery assembly

[0126] The positive electrode sheet, separator, and negative electrode sheet are wound in sequence, so that the separator is between the positive and negative electrode sheets to play a role of isolation, and the electrolyte is added to assemble into a soft-pack battery.

[0127] Embodiment 2:

[0128] This embodiment is basically the same as Embodiment 1, except that: in step (1.1), the stirring and dispersing temperature is 25°C and the stirring and dispersing time is 1 h; in step (1.2), the standing and settling temperature is 25°C and the standing and settling time is 4 h.

[0129] Embodiment 3:

[0130] This embodiment is basically the same as Embodiment 1, except that: in step (1.1), the stirring and dispersing temperature is 50°C; in step (1.2), the static sedimentation temperature is 50°C.

[0131] Embodiment 4:

[0132] This embodiment is basically the same as Embodiment 1, except that: in step (1.1), the stirring and dispersing time is 0.5 h; in step (1.2), the static sedimentation time is 2 h.

[0133] Embodiment 5:

[0134] This embodiment is basically the same as Embodiment 1, except that in step (1.1), the rotation speed of the stirring and dispersing is 1000 r / min.

[0135] Embodiment 6:

[0136] This embodiment is basically the same as embodiment 1, except that in step (1.1), the rotation speed of stirring and dispersing is 2000 r / min.

[0137] Embodiment 7:

[0138] This embodiment is basically the same as Embodiment 1, except that in step (1.3), step (1.1) and step (1.2) are repeated twice.

[0139] Embodiment 8:

[0140] This embodiment is basically the same as Embodiment 1, except that in step (1.3), steps (1.1) and (1.2) are repeated 8 times.

[0141] Embodiment 9:

[0142] This embodiment is basically the same as embodiment 1, except that in step (1.1), the organic solvent is TEP (tetraethylpyrrolidone), and the solid-liquid mass ratio of the recovered material to TEP is 1:2.

[0143] Embodiment 10:

[0144] This embodiment is basically the same as Embodiment 1, except that in step (1.1), the amount of dispersant added is 0.02% of the mass of the ternary positive electrode material to be recycled.

[0145] Embodiment 11:

[0146] This embodiment is basically the same as Embodiment 1, except that in step (1.1), the amount of dispersant added is 2% of the mass of the ternary positive electrode material to be recycled.

[0147] Comparative Example 1:

[0148] This comparative example is basically the same as Example 1, except that: in step (1.1), the stirring and dispersing temperature is 25°C and the stirring and dispersing time is 0.1 h; in step (1.2), the standing and settling temperature is 25°C and the standing and settling time is 0.5 h.

[0149] Comparative Example 2:

[0150] This comparative example is basically the same as Example 1, except that in step (1.3), step (1.1) and step (1.2) are repeated once.

[0151] Comparative Example 3:

[0152] This comparative example is basically the same as Example 1, except that step (1.3) is not provided. That is, the number of repetitions of step (1.1) and step (1.2) is 0.

[0153] Comparative Example 4:

[0154] This comparative example is basically the same as Example 1, except that in step (1.1), no dispersant is added.

[0155] Test Method

[0156] (1) Detection method of carbon content in ternary cathode materials

[0157] The carbon content in the material is tested using a carbon-sulfur high-frequency infrared analyzer. The sample is burned in oxygen using a high-frequency induction furnace to convert carbon into CO2, which enters the absorption cell and is converted into a corresponding signal by the detector. This signal is sampled by a computer, converted into a value proportional to the CO2 concentration after linear correction, and then the values ​​of the entire analysis process are accumulated. After the analysis is completed, this accumulated value is divided by the weight value in the computer, multiplied by the correction coefficient, and the blank is deducted to obtain the percentage of carbon in the sample.

[0158] (2) Detection method of fluorine content in ternary cathode materials

[0159] The ion electrode detection method is used to detect the fluorine content in the recycled ternary cathode material in accordance with the standard: GB / T 6730.28-2021. Specifically:

[0160] a) Weigh 0.2 g (accurate to 0.0001 g) of the sample to be tested into a crucible (silver / nickel crucible is best), weigh 3 g of NaOH to cover the sample, sinter at 600°C for 15 min, and then take out.

[0161] b) Take out the sample and put it into a 100mL plastic beaker. Wash the crucible and leaching with 60mL hot water (60℃) and 10mL HCl (mixture of 1 volume of concentrated hydrochloric acid and 2 volumes of water). Transfer it into a 100mL plastic volumetric flask, shake well, cool it, and then make up the volume.

[0162] c) Pipette 10 mL of the filtered solution into a 100 mL plastic volumetric flask, add 20 mL of sodium citrate solution (294 g / L, adjust the pH to 5 ± 0.1 with HCl), add a few drops of HCl or NaOH to adjust the pH to 5 ± 0.1 (the pH of the sodium citrate buffer solution remains consistent or is slightly adjusted according to the pH difference between the solution after volume adjustment and the F standard solution), and then make up to volume;

[0163] d) Use a relatively accurate fluoride ion electrode to detect the concentration of solution F, ρ F [mg / L];

[0164] e) Calculate the fluorine content ω in the sample F [%]=[ρ F / (10×0.2)]×100%.

[0165] (3) Battery cycle capacity retention rate test method

[0166] The battery was charged to 4.3V at a constant current of 1C at 25°C, then charged at a constant voltage of 4.3V until the current dropped to 0.05C, and then discharged to 2.8V at a constant current of 1C to obtain the first cycle discharge capacity (Cd1); the charge and discharge were repeated until the 100th cycle, and the discharge capacity of the battery after 100 cycles was obtained, recorded as Cd100. The capacity retention rate of the battery after 100 cycles was calculated according to the following formula: Capacity retention rate = discharge capacity after 100 cycles (Cd100) / first cycle discharge capacity (Cd1) × 100%.

[0167] The process parameters and secondary battery performance data of the above embodiments and comparative examples are shown in Table 1 and Table 2. The "ternary positive electrode material to be repaired product" in the table refers to the ternary positive electrode material recovered in step (1.3).

[0168] Table 1

[0169]

[0170] Table 2

[0171]

[0172] It can be seen from Table 1 and Table 2 that the ternary positive electrode material recovered by the recycling method of each embodiment of the present application has good electrochemical performance after repair and lithium supplementation. Using the ternary positive electrode material after repair and lithium supplementation as the positive electrode material of the battery can make the battery have a higher cycle capacity retention rate.

[0173] In Comparative Example 1, the time for stirring, dispersing and settling is insufficient, and the carbon and fluorine elements in the recovered ternary positive electrode material remain relatively large, and the cycle capacity retention rate of the battery is significantly reduced. In Comparative Example 2, compared with Example 1, the number of repetitions of steps one and two is insufficient, which affects the impurity removal effect, and the cycle capacity retention rate of the battery is reduced. In Comparative Example 3, compared with Examples 1 and 2, steps one and two are not repeated, the impurity removal effect is worse, and the cycle capacity retention rate of the battery is lower. In Comparative Example 4, compared with Example 1, no dispersant is used, the separation effect of impurities during the deposition process is poor, and the cycle capacity retention rate of the battery is low.

[0174] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0175] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for recycling ternary positive electrode materials, characterized in that: The following steps are involved: Step 1: Mix the ternary cathode material to be recycled, the organic solvent and the dispersant, and stir and disperse at 25°C to 100°C for 0.2h to 2h to obtain a dispersion; Step 2: allowing the dispersion to settle at 25°C to 100°C for 0.5h to 10h, separating the solid and liquid, and taking the lower solid phase to obtain an intermediate material; Step three: using the intermediate material to replace the ternary positive electrode material to be recycled in step one and repeating step one and step two more than twice to obtain a recycled ternary positive electrode material.

2. The method for recycling ternary cathode materials according to claim 1, characterized in that: The stirring and dispersing temperature is 70°C to 100°C.

3. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The temperature of the static sedimentation is 70°C to 100°C.

4. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: In the step three, the intermediate material is used to replace the ternary positive electrode material to be recycled in step one, and steps one and two are repeated 3 to 8 times.

5. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The stirring and dispersing speed is 500r / min~2000r / min.

6. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The solid-liquid mass volume ratio of the ternary positive electrode material to be recycled and the organic solvent is 1g: (1mL~10mL).

7. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The dispersant includes one or more of carbon black dispersant K-560, organosilicon dispersant K-574 and Anjeka6830 lithium battery slurry dispersant.

8. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The amount of the dispersant added to the dispersion is 0.01% to 2% of the mass of the ternary positive electrode material to be recycled.

9. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetraethylpyrrolidone and dimethyl sulfoxide.

10. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: The ternary positive electrode material to be recycled includes a ternary positive electrode material, a binder and a conductive agent.

11. The method for recycling ternary cathode materials according to claim 1 or 2, characterized in that: After step three, the method further includes filtering, washing and drying the recovered ternary positive electrode material.

12. A ternary positive electrode material, characterized in that: The material is recovered by the method for recovering the ternary positive electrode material according to any one of claims 1 to 11.

13. A secondary battery, characterized in that: It includes a positive electrode plate, the positive electrode plate includes a positive electrode film layer, and the positive electrode film layer includes the ternary positive electrode material obtained after the ternary positive electrode material according to claim 12 is repaired by lithium supplementation.

14. An electrical device, characterized in that: Includes the secondary battery as claimed in claim 13.

Images