Recycling method for waste lithium-ion battery positive electrode material and lithium-ion battery positive electrode material

Abstract

The present invention provides a recycling and cyclic utilization method of waste lithium-ion battery positive electrode materials and lithium-ion battery positive electrode materials. The recycling and cyclic utilization method comprises: pre-treating waste lithium-ion battery positive electrode sheets and then wet-grinding and wet-sieving to separate the current collector and positive electrode waste in the waste lithium-ion battery positive electrode sheets, and then washing the positive electrode waste to obtain the positive electrode material. The present invention can achieve efficient separation of positive electrode waste and current collector at room temperature, and further improves the recovery rate and purity of the recovered positive electrode material through the mutual coordination of wet grinding, wet screening and washing treatment, so that it has the possibility of being directly used as the positive electrode material in the battery manufacturing process. At the same time, the solvents used in the recycling and cyclic utilization method of waste lithium-ion battery positive electrode materials provided by the present invention can be recycled and cyclically utilized, the process pollution is low, and it is easy to promote industrialization.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium ion battery recycling, and in particular relates to a recycling method for waste lithium ion battery positive electrode materials and lithium ion battery positive electrode materials. Background Art

[0002] With the booming development of new energy vehicles, the demand for lithium-ion batteries has also doubled. However, the life of lithium-ion batteries is very short, generally about 3 years. Waste lithium-ion batteries contain a lot of recyclable valuable energy materials such as nickel, cobalt, manganese, lithium, iron, copper, aluminum, etc., and the electrolyte in waste lithium-ion batteries will also pollute the environment. At the same time, waste power batteries also have the potential to explode. Therefore, it is urgent to recycle waste lithium-ion batteries.

[0003] After discharge, preliminary crushing and other processes, waste lithium-ion batteries can obtain positive and negative electrode waste containing current collectors. However, due to the presence of organic binders, it is difficult to separate the positive and negative electrode waste from the current collector. At present, the commonly used separation methods are high-temperature pyrolysis, organic solvent dissolution of binders, and strong alkali dissolution of current collectors. Among them, high-temperature pyrolysis has high energy consumption and the fluorine-containing waste gas produced is difficult to treat; the organic dissolution binder method uses mostly toxic and volatile solvents; the strong alkali dissolution method has high heat release, difficult to control temperature, and is accompanied by the generation of flammable gases, and has high requirements for equipment.

[0004] CN108470955A discloses a recycling method for lithium-ion battery positive plates, which includes dissolving the scrapped positive plates with an organic solvent at a temperature of 250-400°C, separating the positive current collector and the material slurry, and then removing the positive material by vibration screening. However, this method uses high-temperature organic dissolution, the organic solvent evaporates quickly, the circulation is poor, and the tail gas needs special treatment, which is not suitable for industrial application.

[0005] CN107069134A discloses a method for separating the positive electrode material and the current collector of waste lithium batteries, which comprises crushing the positive electrode sheet to a certain particle size and then burning it at 200-300°C to separate the positive electrode material from the current collector. However, this method has high energy consumption and is accompanied by fluorine-containing waste gas, which is not suitable for large-scale industrial production. At present, most of the recovered positive electrode waste is sold directly or enters the chemical leaching section to extract valuable elements, which undoubtedly increases the process flow and also increases the recovery cost.

[0006] CN108306071A discloses a recycling process for cathode materials of waste lithium-ion batteries, which comprises disassembling waste lithium-ion batteries and subjecting them to high-temperature treatment in a tubular furnace; immersing the obtained cathode materials in an acidic solution to dissolve and obtain a filtrate; then extracting the filtrate and adjusting the raw material composition according to the designed element ratio of the cathode material precursor to obtain the cathode material. This method also has the problem of high energy consumption of high-temperature pyrolysis and difficulty in treating the generated fluorine-containing waste gas.

[0007] The currently available waste lithium-ion battery recycling technologies all have unavoidable defects and cannot achieve the technical effect of efficient, green and economical recycling of positive electrode materials in lithium-ion batteries. Therefore, it is very important to develop and design a new recycling method for waste lithium-ion battery positive electrode materials. Summary of the invention

[0008] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for recycling and reusing waste lithium-ion battery positive electrode materials and a positive electrode material for lithium-ion batteries, which can achieve efficient separation of positive electrode waste and current collector at room temperature, and further improve the recovery rate and purity of the recovered positive electrode materials through the mutual cooperation between wet grinding, wet screening and washing treatment, so that it is possible to directly use it as a positive electrode material in the battery manufacturing process. At the same time, by introducing electrochemical performance detection and positive electrode material repair, the positive electrode material can be directly recycled to the battery manufacturing coating process, realizing the recycling of the positive electrode material, with a wide range of applications, simple process operation, low process pollution, and easy industrial promotion. In addition, the solvents used in the method for recycling and reusing waste lithium-ion battery positive electrode materials provided by the present invention can be recycled, reducing recycling costs and avoiding environmental pollution.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for recycling and reusing waste lithium-ion battery positive electrode materials, the recycling and reusing method comprising:

[0011] The waste lithium ion battery positive electrode sheets are pretreated and then wet-milled and wet-screened to separate the current collector and positive electrode waste in the waste lithium ion battery positive electrode sheets, and then the positive electrode waste is washed to obtain the positive electrode material.

[0012] The present invention adopts wet grinding and wet screening, which can conveniently realize the classified recycling of current collector and positive electrode waste, realize the reuse of raw materials, and reduce production costs; and the positive electrode waste is washed to completely remove the organic binder, further improving the recovery rate and purity of the recovered positive electrode material. In addition, the solvents used in the pretreatment, wet grinding and washing processes can be recycled, reducing costs and reducing process pollution.

[0013] The recycling and reuse method of waste lithium-ion battery positive electrode materials provided by the present invention can achieve efficient separation of positive electrode waste and current collector at room temperature, and further improve the purity of the recovered positive electrode materials through the cooperation between wet grinding, wet screening and washing treatment, so that it is possible to directly use it as a positive electrode material in the battery manufacturing process. In addition, the recycling and reuse method of waste lithium-ion battery positive electrode materials provided by the present invention effectively realizes the recycling of positive electrode materials, has a wide range of applications, simple process operation, low process pollution, and is easy to promote industrialization.

[0014] As a preferred technical solution of the present invention, the pretreatment process includes:

[0015] The waste lithium-ion battery positive electrode sheet is placed in a solvent for soaking treatment, and then separated to obtain a separation liquid and a mixed material, and the separation liquid is returned to the soaking treatment process for recycling.

[0016] The present invention pre-treats the waste lithium-ion battery positive electrode sheet, and uses a solvent dissolution method to weaken the adhesion of the organic binder without destroying the performance of the positive electrode waste, so that the positive electrode waste is more easily separated from the current collector, and a mixed material of the current collector and the positive electrode waste is obtained. In addition, the present invention performs pre-treatment at room temperature, effectively avoiding the problem that the solvent is easy to volatilize at high temperature, and the separation liquid obtained after separation can be recycled.

[0017] In addition, the positive electrode sheet of the waste lithium-ion battery in the present invention is a positive electrode sheet obtained from production scraps / or manually dismantled waste lithium-ion batteries; the size of the positive electrode sheet of the waste lithium-ion battery is preferably (0.5-5)×(0.5-5) cm.

[0018] Preferably, the solvent is an organic solvent.

[0019] Preferably, the solvent comprises any one or a combination of at least two of N-methylpyrrolidone, acetone, formic acid, acetic acid, dimethyl sulfoxide, triethyl phosphate, ascorbic acid or tetrahydrofuran.

[0020] Preferably, the solid-to-liquid ratio of the waste lithium ion battery positive electrode sheet to the solvent in the immersion treatment is 1 to 50 g / mL, for example, it can be 1 g / mL, 5 g / mL, 10 g / mL, 15 g / mL, 20 g / mL, 25 g / mL, 30 g / mL, 35 g / mL, 40 g / mL, 45 g / mL or 50 g / mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the immersion treatment time is 10 to 120 min, for example, it can be 10 min, 10 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] As a preferred technical solution of the present invention, the process of wet grinding and wet screening includes:

[0023] The mixed material is placed in a wet grinding solvent and wet-ground under stirring, and then the wet grinding solvent, the current collector and the positive electrode waste are separated by wet screening, and the wet grinding solvent is returned to the wet grinding process for recycling.

[0024] Wet grinding and wet screening are used to achieve classified recovery of positive electrode waste, current collector and wet grinding solvent. The current collector used in the present invention is preferably aluminum foil. At the same time, the wet grinding and wet screening processes in the present invention both use demagnetization equipment.

[0025] As a preferred technical solution of the present invention, the wet grinding method includes medium drum ball milling or medium drum rod milling.

[0026] Preferably, the grinding media for wet grinding comprises any one of plastic balls, zirconium balls, plastic rods or zirconium ball rods, or a combination of at least two of them.

[0027] Preferably, the wet grinding solvent is water.

[0028] Preferably, during the wet grinding process, the mass ratio of the mixed material to the grinding medium is 1:(1-20), for example, it can be 1:1, 1:2, 1:5, 1:8, 1:10, 1:13, 1:15, 1:18 or 1:20, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, during the wet grinding process, the solid-to-liquid ratio of the mixture to water is 1 to 50 g / mL, for example, 1 g / mL, 5 g / mL, 10 g / mL, 15 g / mL, 20 g / mL, 25 g / mL, 30 g / mL, 35 g / mL, 40 g / mL, 45 g / mL or 50 g / mL, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the stirring rate is 100 to 1000 rpm / min, for example, it can be 100 rpm / min, 200 rpm / min, 400 rpm / min, 500 rpm / min, 600 rpm / min, 800 rpm / min or 1000 rpm / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the wet grinding time is 10 to 120 min, for example, it can be 10 min, 10 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] As a preferred technical solution of the present invention, the washing solvent used in the washing treatment is an organic solvent.

[0033] In the present invention, the washing solvent can be recycled.

[0034] Preferably, the washing solvent comprises any one of N-methylpyrrolidone, acetone, formic acid, acetic acid, dimethyl sulfoxide, triethyl phosphate, ascorbic acid or tetrahydrofuran, or a combination of at least two thereof.

[0035] Preferably, the solid-to-liquid ratio of the positive electrode waste to the washing solvent in the washing treatment is 1 to 50 g / mL, for example, 1 g / mL, 5 g / mL, 10 g / mL, 15 g / mL, 20 g / mL, 25 g / mL, 30 g / mL, 35 g / mL, 40 g / mL, 45 g / mL or 50 g / mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the washing treatment is washed 1 to 10 times, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 times, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the washing time for a single time is 10 to 120 min, for example, it can be 10 min, 10 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] As a preferred technical solution of the present invention, the recycling method further comprises:

[0039] The positive electrode material obtained by the washing treatment is subjected to an electrochemical performance test, and the positive electrode material that passes the test is recycled to the coating process of battery manufacturing, and the positive electrode material that fails the test is repaired and then recycled to the coating process of battery manufacturing.

[0040] The present invention introduces electrochemical performance detection and positive electrode material repair, and can directly recycle the positive electrode material to the battery manufacturing coating process to achieve the recycling of the positive electrode material. The positive electrode material repair process in the present invention includes: according to the content of each metal element in the target positive electrode material, the metal element is supplemented to the positive electrode material that fails the electrochemical performance detection, so as to achieve the recycling of the positive electrode material.

[0041] As a preferred technical solution of the present invention, the recycling method comprises:

[0042] (1) placing the waste lithium-ion battery positive electrode sheet in a solvent at a solid-liquid ratio of 1 to 50 g / mL for immersion treatment for 10 to 120 minutes, then separating to obtain a separated liquid and a mixed material, and returning the separated liquid to the immersion treatment process for recycling;

[0043] (2) placing the mixed material obtained in step (1) in a wet grinding solvent at a solid-liquid ratio of 1 to 50 g / mL, with a mass ratio of the mixed material to the grinding medium of 1:(1 to 20), and wet grinding for 10 to 120 min at a stirring speed of 100 to 1000 rpm / min, followed by wet sieving to separate the wet grinding solvent, the current collector and the positive electrode waste, and the wet grinding solvent is returned to the wet grinding process for recycling;

[0044] (3) placing the cathode waste obtained in step (2) in a washing solvent at a solid-liquid ratio of 1 to 50 g / mL, washing 1 to 10 times to obtain a cathode material, wherein the time for a single washing is 10 to 120 min;

[0045] (4) drying the positive electrode material obtained in step (3) and then testing its electrochemical performance, recycling the positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0046] In the present invention, the waste lithium-ion batteries are firstly subjected to a discharge treatment, and the waste lithium-ion battery positive plates are separated by a simple physical shredder. The waste lithium-ion battery positive plates in the production process can also be used as the raw materials of the present invention.

[0047] In a second aspect, the present invention provides a positive electrode material for a lithium-ion battery, wherein the positive electrode material for a lithium-ion battery is prepared by the recycling method described in the first aspect.

[0048] As a preferred technical solution of the present invention, the lithium-ion battery positive electrode material includes any one of cobalt-based positive electrode material, manganese-based positive electrode material, nickel-based material or lithium iron phosphate, or a combination of at least two thereof.

[0049] The combined form of the positive electrode material for lithium-ion batteries in the present invention includes a combination of a cobalt-based positive electrode material and a nickel-based positive electrode material, a combination of a nickel-based positive electrode material and a manganese-based positive electrode material, a combination of a cobalt-based positive electrode material and a manganese-based positive electrode material, a combination of a lithium iron phosphate positive electrode material and a cobalt-based material, a combination of a lithium iron phosphate positive electrode material and a manganese-based positive electrode material, or a combination of a cobalt-based positive electrode material, a manganese-based positive electrode material and a nickel-based positive electrode material, etc.

[0050] As a preferred technical solution of the present invention, the active substance in the positive electrode material of the lithium-ion battery includes any one or a combination of at least two of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide or lithium iron phosphate.

[0051] The active materials in combined form in the present invention include a combination of lithium cobalt oxide and lithium nickel oxide, a combination of lithium nickel oxide and lithium manganese oxide, a combination of lithium manganese oxide and nickel cobalt manganese oxide, a combination of lithium nickel cobalt manganese oxide and nickel cobalt aluminum oxide, a combination of lithium nickel cobalt aluminum oxide and lithium iron phosphate, a combination of lithium iron phosphate and lithium cobalt oxide, or a combination of lithium nickel oxide, lithium manganese oxide and nickel cobalt manganese oxide, etc.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) The recycling and reuse method of waste lithium-ion battery positive electrode materials provided by the present invention can achieve efficient separation of positive electrode waste and current collector at room temperature and pressure, avoiding the phenomenon of organic solvent volatilization and generation of fluorine-containing waste gas at high temperature, and the separation efficiency can reach more than 90%. The recycling and reuse method of waste lithium-ion battery positive electrode materials provided by the present invention has a wide range of applications, simple process operation, all solvents used in the recycling process can be recycled, the process pollution is low, and it is easy to promote industrialization.

[0054] (2) The present invention adopts wet grinding and wet screening, which can conveniently realize the classified recycling of current collector and positive electrode waste, realize the reuse of raw materials, and reduce production costs. At the same time, the recycled positive electrode waste is washed to completely remove the organic binder, further improving the recovery rate and purity of the recycled positive electrode material, making it possible to directly use it as the positive electrode material in the battery manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1It is a process flow chart of the method for recycling and reusing the positive electrode material of waste lithium-ion batteries provided in Examples 1 to 10 of the present invention. DETAILED DESCRIPTION

[0056] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] Example 1

[0058] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0059] (1) placing a waste nickel-cobalt-manganese-oxide lithium positive electrode sheet with a size of 5×5 cm in N-methylpyrrolidone at a solid-liquid ratio of 10 g / mL for immersion treatment for 120 min, then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0060] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 10 g / mL, with a mass ratio of the mixed material to the zirconium ball being 1:10, and wet grinding for 30 min using a medium drum ball mill at a stirring speed of 500 rpm / min, followed by wet sieving to obtain water, aluminum foil, and nickel cobalt manganese oxide lithium positive electrode waste, and the water is returned to the wet grinding process for recycling;

[0061] (3) placing the nickel cobalt manganese oxide positive electrode waste obtained in step (2) in N-methylpyrrolidone at a solid-liquid ratio of 5 g / mL, 8 g / mL and 10 g / mL, respectively, and washing three times to obtain a nickel cobalt manganese oxide positive electrode material, with a single washing time of 20 min;

[0062] (4) drying the nickel cobalt manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the nickel cobalt manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the nickel cobalt manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0063] Example 2

[0064] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0065] (1) placing a waste lithium iron phosphate positive electrode sheet with a size of 3×3 cm in triethyl phosphate at a solid-liquid ratio of 15 g / mL for immersion treatment for 100 minutes, then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0066] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 5 g / mL, with a mass ratio of the mixed material to the plastic ball being 1:15, and wet-milling for 25 min using a medium drum ball mill at a stirring speed of 300 rpm / min, followed by wet sieving to obtain water, aluminum foil, and lithium iron phosphate cathode waste, and the water is returned to the wet milling process for recycling;

[0067] (3) placing the lithium iron phosphate cathode waste obtained in step (2) in triethyl phosphate at a solid-liquid ratio of 5 g / mL and 10 g / mL respectively, and washing twice to obtain a lithium iron phosphate cathode material, with a single washing time of 25 min;

[0068] (4) drying the lithium iron phosphate positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the lithium iron phosphate positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the lithium iron phosphate positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0069] Example 3

[0070] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0071] (1) placing a waste lithium manganese oxide positive electrode sheet with a size of 2.5×2.5 cm in acetone at a solid-liquid ratio of 12 g / mL for immersion treatment for 110 min, then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0072] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 20 g / mL, with a mass ratio of the mixed material to the plastic rod being 1:10, and wet-milling for 27 min using a medium roller rod mill at a stirring speed of 600 rpm / min, followed by wet sieving to obtain water, aluminum foil, and lithium manganese oxide positive electrode waste, and the water is returned to the wet milling process for recycling;

[0073] (3) placing the lithium manganese oxide positive electrode waste obtained in step (2) in triethyl phosphate at a solid-liquid ratio of 5 g / mL and 8 g / mL respectively, and washing twice to obtain a lithium manganese oxide positive electrode material, with a single washing time of 28 min;

[0074] (4) drying the lithium manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the lithium manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the lithium manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0075] Example 4

[0076] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0077] (1) placing a waste lithium iron phosphate positive electrode sheet with a size of 3×3 cm in a mixed solution of formic acid and acetic acid in a ratio of 1:1 at a solid-liquid ratio of 5 g / mL for immersion treatment for 100 minutes, then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0078] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 25 g / mL, with a mass ratio of the mixed material to the zirconium ball rod being 1:5, and wet-milling for 35 min using a medium roller rod mill at a stirring speed of 800 rpm / min, followed by wet sieving to obtain water, aluminum foil and lithium iron phosphate positive electrode waste, and the water is returned to the wet milling process for recycling;

[0079] (3) placing the lithium iron phosphate cathode waste obtained in step (2) in N-methylpyrrolidone at a solid-liquid ratio of 5 g / mL, 8 g / mL and 10 g / mL, respectively, and washing three times to obtain a lithium iron phosphate cathode material, with a single washing time of 20 min;

[0080] (4) drying the lithium iron phosphate positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the lithium iron phosphate positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the lithium iron phosphate positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0081] Example 5

[0082] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0083] (1) placing a waste cobalt nickel lithium manganese oxide positive electrode sheet with a size of 3×2 cm in a solid-liquid ratio of 15 g / mL in an ascorbic acid solution with a mass fraction of 25 wt % for immersion treatment for 100 min, and then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0084] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 15 g / mL, with a mass ratio of the mixed material to the zirconium ball rod being 1:8, and wet-milling for 40 min using a medium roller rod mill at a stirring speed of 400 rpm / min, followed by wet sieving to obtain water, aluminum foil, and cobalt nickel manganese oxide lithium positive electrode waste, and the water is returned to the wet milling process for recycling;

[0085] (3) placing the lithium cobalt nickel manganese oxide positive electrode waste obtained in step (2) in an ascorbic acid solution with a mass fraction of 25 wt % at a solid-liquid ratio of 5 g / mL, 8 g / mL and 10 g / mL, respectively, and washing three times to obtain a lithium cobalt nickel manganese oxide positive electrode material, with a single washing time of 20 min;

[0086] (4) drying the cobalt nickel manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the cobalt nickel manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the cobalt nickel manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0087] Example 6

[0088] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0089] (1) placing a waste cobalt nickel lithium manganese oxide positive electrode sheet with a size of 4×2 cm in a tetrahydrofuran solution at a solid-liquid ratio of 18 g / mL for immersion treatment for 100 minutes, then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0090] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 25 g / mL, with a mass ratio of the mixed material to the zirconium ball being 1:10, and wet grinding for 40 min using a medium drum ball mill at a stirring speed of 500 rpm / min, followed by wet sieving to obtain water, aluminum foil, and cobalt nickel manganese oxide lithium positive electrode waste, and the water is returned to the wet grinding process for recycling;

[0091] (3) placing the lithium cobalt nickel manganese oxide positive electrode waste obtained in step (2) in a tetrahydrofuran solution at a solid-liquid ratio of 10 g / mL and 15 g / mL respectively, and washing twice to obtain a lithium cobalt nickel manganese oxide positive electrode material, with a single washing time of 28 min;

[0092] (4) drying the cobalt nickel manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the cobalt nickel manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the cobalt nickel manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0093] Example 7

[0094] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0095] (1) placing a waste lithium iron phosphate positive electrode sheet with a size of 4.5×3.5 cm in a formic acid solution with a solid-liquid ratio of 5 g / mL for immersion treatment for 60 minutes, and then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0096] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 15 g / mL, with a mass ratio of the mixed material to the zirconium ball being 1:15, and wet grinding for 30 min using a medium drum ball mill at a stirring speed of 500 rpm / min, followed by wet sieving to obtain water, aluminum foil and lithium iron phosphate positive electrode waste, and the water is returned to the wet grinding process for recycling;

[0097] (3) placing the lithium iron phosphate cathode waste obtained in step (2) in a dimethyl sulfoxide solution at a solid-liquid ratio of 10 g / mL and 25 g / mL respectively, washing twice to obtain a lithium iron phosphate cathode material, with a single washing time of 30 min;

[0098] (4) drying the lithium iron phosphate positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the lithium iron phosphate positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the lithium iron phosphate positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0099] Example 8

[0100] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0101] (1) placing a waste lithium manganese oxide positive electrode sheet with a size of 4×3.5 cm in a formic acid solution with a solid-liquid ratio of 5 g / mL for immersion treatment for 60 minutes, and then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0102] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 15 g / mL, with a mass ratio of the mixed material to the zirconium ball being 1:15, and wet grinding for 30 min using a medium drum ball mill at a stirring speed of 500 rpm / min, followed by wet sieving to obtain water, aluminum foil and lithium manganese oxide positive electrode waste, and the water is returned to the wet grinding process for recycling;

[0103] (3) placing the lithium manganese oxide positive electrode waste obtained in step (2) in a triethyl phosphate solution at a solid-liquid ratio of 10 g / mL and 25 g / mL respectively, washing twice to obtain a lithium manganese oxide positive electrode material, and the single washing time is 30 min;

[0104] (4) drying the lithium manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the lithium manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the lithium manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0105] Example 9

[0106] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0107] (1) placing a waste nickel-cobalt-manganese-oxide lithium positive electrode sheet with a size of 4×4 cm in an N-methylpyrrolidone solution at a solid-liquid ratio of 1 g / mL for immersion treatment for 10 minutes, and then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0108] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 50 g / mL, with a mass ratio of the mixed material to the zirconium ball being 1:20, and wet grinding for 10 min using a medium drum ball mill at a stirring speed of 1000 rpm / min, followed by wet sieving to obtain water, aluminum foil, and nickel cobalt manganese oxide lithium positive electrode waste, and the water is returned to the wet grinding process for recycling;

[0109] (3) placing the nickel cobalt manganese oxide positive electrode waste obtained in step (2) in an N-methylpyrrolidone solution at a solid-liquid ratio of 1 g / mL, washing once to obtain a nickel cobalt manganese oxide positive electrode material, and the single washing time is 120 min;

[0110] (4) drying the nickel cobalt manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the nickel cobalt manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the nickel cobalt manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0111] Example 10

[0112] This embodiment provides a method for recycling and reusing waste lithium-ion battery positive electrode materials. Figure 1 As shown, the recycling method includes:

[0113] (1) placing a waste nickel cobalt manganese oxide lithium positive electrode sheet with a size of 4×4 cm in an N-methylpyrrolidone solution at a solid-liquid ratio of 50 g / mL for immersion treatment for 120 minutes, then separating to obtain a separated liquid and a mixed material, and the separated liquid is returned to the immersion treatment process for recycling;

[0114] (2) placing the mixed material obtained in step (1) in water at a solid-liquid ratio of 1 g / mL, with a mass ratio of the mixed material to the zirconium ball being 1:1, and wet grinding for 10 min using a medium roller ball mill at a stirring speed of 100 rpm / min, followed by wet sieving to obtain water, aluminum foil, and nickel cobalt manganese oxide lithium positive electrode waste, and the water is returned to the wet grinding process for recycling;

[0115] (3) washing the lithium nickel cobalt manganese oxide positive electrode waste obtained in step (2) in an N-methyl pyrrolidone solution at a solid-liquid ratio of 5 g / mL for 4 times, washing in an N-methyl pyrrolidone solution at a solid-liquid ratio of 10 g / mL for 4 times, washing in an N-methyl pyrrolidone solution at a solid-liquid ratio of 40 g / mL for 1 time, and washing in an N-methyl pyrrolidone solution at a solid-liquid ratio of 50 g / mL for 1 time to obtain a lithium nickel cobalt manganese oxide positive electrode material, wherein the single washing time is 10 min;

[0116] (4) drying the nickel cobalt manganese oxide positive electrode material obtained in step (3) and then conducting an electrochemical performance test, recycling the nickel cobalt manganese oxide positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the nickel cobalt manganese oxide positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

[0117] Comparative Example 1

[0118] The difference between this comparative example and Example 1 is that step (2) is omitted, that is, the mixture of aluminum foil and positive electrode waste obtained in step (1) is directly dried and sieved to obtain positive electrode material, and the remaining process parameters and operating steps are the same as those in Example 1.

[0119] Comparative Example 2

[0120] The difference between this comparative example and Example 1 is that step (3) is omitted, that is, the positive electrode waste obtained in step (2) is directly dried to obtain the positive electrode material, and the remaining process parameters and operating steps are the same as those in Example 1.

[0121] Comparative Example 3

[0122] The difference between this comparative example and Example 1 is that step (1), that is, the pretreatment step, is omitted, and the remaining process parameters and operating steps are the same as those of Example 1.

[0123] The purity of aluminum foil and the recovery rate of positive electrode materials in Examples 1-10 and Comparative Examples 1-3 are shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] The positive electrode materials prepared in Examples 1-10 and Comparative Examples 1-3 were subjected to electrochemical performance tests. 90% of the positive electrode material by mass, 5% of acetylene black by mass and 5% of polyvinylidene fluoride by mass were stirred and slurried in N-methylpyrrolidone solvent, and the positive electrode slurry was coated on aluminum foil to obtain a positive electrode sheet; a metal lithium sheet was used as the negative electrode, a polypropylene microporous film was used as the diaphragm, and 1 mol / L LiPF6 / EC+DEC (mass ratio of 1:1) was used as the electrolyte to conduct electrochemical performance tests:

[0128] (1) First charge and discharge specific capacity test: the voltage range is 2.5-3.5V, the current density is 1C, and the test results are shown in Table 2. Among them, 1C is the current required for the battery to discharge the rated capacity of 170mAh / g in 1h.

[0129] (2) Cycle performance test: Under the conditions of voltage range of 2.5-3.5V and current density of 1C, after a certain number of charge and discharge cycles (different positive electrode materials correspond to different number of cycles), the charge specific capacity and discharge specific capacity are tested respectively, and the capacity retention rate is calculated.

[0130] The electrochemical performance test results of the positive electrode materials obtained in Examples 1-10 and Comparative Examples 1-3 are shown in Table 2.

[0131] Table 2

[0132]

[0133] From the data analysis of Table 1, we can get:

[0134] (1) The purity of the aluminum foil and the recovery rate of the positive electrode material in Examples 1-10 are both above 90%, indicating that the method for recycling and reusing waste lithium-ion battery positive electrode materials provided by the present invention can achieve efficient separation of positive electrode waste and current collector at room temperature, and can conveniently achieve classified recovery of current collector and positive electrode waste through wet grinding and wet screening. At the same time, washing the recycled positive electrode waste can completely remove the organic binder, further improving the recovery rate and purity of the recycled positive electrode material.

[0135] (2) The purity of the aluminum foil and the recovery rate of the positive electrode material in Comparative Example 1 are lower than those in Example 1. This is because Comparative Example 1 omits the steps of wet grinding and wet screening, which makes it impossible to effectively separate and recover the positive electrode waste and the current collector; the purity of the aluminum foil in Comparative Example 2 is not much different from that in Example 1, but the recovery rate of the positive electrode material is lower than that in Example 1. This is because Comparative Example 2 omits the step of washing treatment, and the washing treatment is mainly used to further improve the recovery rate and purity of the positive electrode material; the purity of the aluminum foil and the recovery rate of the positive electrode material in Comparative Example 3 are lower than those in Example 1. This is because Comparative Example 3 omits the pretreatment step, the adhesion of the organic binder is not weakened in advance, and the positive electrode waste is difficult to separate from the current collector during wet grinding and wet screening, which leads to a decrease in the purity of the current collector and the recovery rate of the positive electrode material.

[0136] From the data analysis of Table 2, we can get:

[0137] (1) The electrochemical properties of the positive electrode materials recovered in Examples 1-10 are all relatively good, among which the positive electrode materials obtained in Examples 2, 4 and 7 can be directly returned to the coating process, and the electrochemical properties of the positive electrode materials in the remaining examples are also close to the standard of directly returning to the coating process, and return to the coating process after simple material repair. Therefore, the positive electrode material obtained by the recycling and reuse method of waste lithium-ion battery positive electrode materials provided by the present invention has excellent electrochemical properties and has the possibility of being directly returned to the battery manufacturing coating process, thereby realizing the recycling of positive electrode materials.

[0138] (2) The electrochemical properties of the positive electrode materials recovered in Comparative Examples 1-3 are all lower than those in Example 1. This is because Comparative Example 1 omits the wet grinding and wet screening steps, Comparative Example 2 omits the washing treatment step, and Comparative Example 3 omits the pretreatment step, resulting in the inability to effectively separate and recover the positive electrode waste and the current collector in Comparative Examples 1-3, and the recovery rate and purity of the positive electrode materials are both low, resulting in the electrochemical properties of the recovered positive electrode materials being lower than those in Example 1.

[0139] The applicant declares that the above is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recycling and reusing waste lithium-ion battery positive electrode materials, characterized in that: The recycling method is as follows: Pre-treating the waste lithium-ion battery positive electrode sheets and performing wet grinding and wet screening to separate the current collector and positive electrode waste in the waste lithium-ion battery positive electrode sheets, and then washing the positive electrode waste to obtain positive electrode materials; The pretreatment process includes: placing the waste lithium-ion battery positive electrode sheet in an organic solvent for soaking treatment, then separating to obtain a separation liquid and a mixed material, and the separation liquid is returned to the soaking treatment process for recycling; The organic solvent includes any one or a combination of at least two of N-methylpyrrolidone, formic acid, acetic acid, dimethyl sulfoxide, triethyl phosphate, ascorbic acid or tetrahydrofuran; The wet grinding and wet screening process comprises: placing the mixed material in a wet grinding solvent, wet grinding under stirring, and then separating the wet grinding solvent, the current collector and the positive electrode waste by wet screening, and the wet grinding solvent is returned to the wet grinding process for recycling; During the wet grinding process, the mass ratio of the mixed material to the grinding medium is 1:(1-20); During the wet grinding process, the solid-to-liquid ratio of the mixed material to the wet grinding solvent is 1 to 50 g / mL; The washing solvent used in the washing treatment is an organic solvent.

2. The recycling method according to claim 1, characterized in that: The solid-to-liquid ratio of the waste lithium-ion battery positive electrode sheet to the solvent in the immersion treatment is 1 to 50 g / mL.

3. The recycling method according to claim 1, characterized in that: The soaking treatment time is 10 to 120 minutes.

4. The recycling method according to claim 1, characterized in that: The wet grinding method includes medium roller ball milling or medium roller rod milling.

5. The recycling method according to claim 4, characterized in that: The grinding media for wet grinding includes any one of plastic balls, zirconium balls, plastic rods or zirconium ball rods, or a combination of at least two of them.

6. The recycling method according to claim 1, characterized in that: The wet grinding solvent is water.

7. The recycling method according to claim 1, characterized in that: The stirring rate is 100-1000 rpm / min.

8. The recycling method according to claim 1, characterized in that: The wet grinding time is 10 to 120 minutes.

9. The recycling method according to claim 1, characterized in that: The washing solvent includes any one of N-methylpyrrolidone, acetone, formic acid, acetic acid, dimethyl sulfoxide, triethyl phosphate, ascorbic acid or tetrahydrofuran, or a combination of at least two thereof.

10. The recycling method according to claim 1, characterized in that: In the washing process, the solid-to-liquid ratio of the positive electrode waste to the washing solvent is 1 to 50 g / mL.

11. The recycling method according to claim 1, characterized in that: The washing process is performed 1 to 10 times.

12. The recycling method according to claim 1, characterized in that: The washing time for a single time is 10 to 120 minutes.

13. The recycling method according to claim 1, characterized in that: The recycling method also includes: The positive electrode material obtained by the washing treatment is subjected to an electrochemical performance test, and the positive electrode material that passes the test is recycled to the coating process of battery manufacturing, and the positive electrode material that fails the test is repaired and then recycled to the coating process of battery manufacturing.

14. The recycling method according to claim 1, characterized in that: The recycling method comprises: (1) placing the waste lithium-ion battery positive electrode sheet in a solvent at a solid-liquid ratio of 1 to 50 g / mL for immersion treatment for 10 to 120 minutes, then separating to obtain a separated liquid and a mixed material, and returning the separated liquid to the immersion treatment process for recycling; (2) placing the mixed material obtained in step (1) in a wet grinding solvent at a solid-liquid ratio of 1 to 50 g / mL, with a mass ratio of the mixed material to the grinding medium of 1:(1 to 20), and wet grinding for 10 to 120 min at a stirring speed of 100 to 1000 rpm / min, followed by wet sieving to separate the wet grinding solvent, the current collector and the positive electrode waste, and the wet grinding solvent is returned to the wet grinding process for recycling; (3) placing the cathode waste obtained in step (2) in a washing solvent at a solid-liquid ratio of 1 to 50 g / mL, washing 1 to 10 times to obtain a cathode material, wherein the time for a single washing is 10 to 120 min; (4) drying the positive electrode material obtained in step (3) and then testing its electrochemical performance, recycling the positive electrode material that passes the test to the coating process of battery manufacturing, and repairing the positive electrode material that fails the test and then recycling it to the coating process of battery manufacturing.

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