A method for recycling cathode materials from waste ternary lithium-ion batteries

Abstract

The present invention relates to the technical field of lithium-ion battery recycling and utilization, and specifically discloses a method for recycling and regenerating positive electrode materials from waste ternary lithium-ion batteries. The present invention uses a ternary deep eutectic solvent combined with microwave-assisted leaching to efficiently leach waste lithium-ion battery positive electrode materials, and then combines subsequent precipitation and adjustment of the molar ratio of metal elements to regenerate the positive electrode materials. The obtained recycled and regenerated positive electrode materials have good electrochemical properties. The technical solution provided by the present invention effectively solves the problems of high cost and complicated process flow of the existing method for recycling metals from waste ternary lithium-ion batteries, and the problem that when the recovered metals are used to prepare lithium battery positive electrode materials, the purity is insufficient, resulting in poor effect of the regenerated positive electrode materials. It provides a new idea for the treatment of waste ternary lithium-ion batteries.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery recycling and utilization, and specifically discloses a method for recycling and regenerating positive electrode materials from waste ternary lithium ion batteries. Background Art

[0002] Among the many chemical power sources, lithium-ion batteries have high energy density, long storage life, and small size.

[0003] Lithium-ion batteries are favored for their advantages, such as small size, light weight, low self-discharge efficiency, and lack of memory effect. With the continued rise in global penetration of new energy vehicles, demand for automotive power batteries and energy storage batteries continues to grow at a high rate. However, other battery systems currently face difficulties in large-scale industrial development, and lithium-ion batteries will remain the mainstream energy storage chemical power source. However, due to the growing demand for lithium-ion batteries, their raw materials are also gaining widespread attention. Due to global shortages of key elements such as cobalt, nickel, and lithium, lithium-ion battery production is expected to be impacted by resource shortages by 2050. Since the cathode materials of used lithium-ion batteries are rich in cobalt, nickel, and lithium, recycling used lithium-ion batteries has become a key way to alleviate resource pressures. Furthermore, used lithium-ion batteries contain many toxic substances. If not properly stored and disposed of, the harm they pose to the social environment and human health cannot be underestimated.

[0004] Currently, metal recovery from spent lithium-ion batteries primarily involves extracting metals or metal oxides through a combination of mechanical treatment of the cathode materials, hydrometallurgy, or pyrometallurgy. However, mechanical treatment takes a long time and incurs significant equipment wear. Hydrometallurgy is the mainstream method in the current recycling field, offering advantages such as mild reaction conditions, low tail gas emissions, and high metal recovery rates. However, hydrometallurgy requires large amounts of inorganic or organic acids, particularly organic acids, which are generally expensive and thus require high processing costs. Pyrometallurgy, on the other hand, involves recovering or refining valuable metals from spent lithium-ion batteries through physical or chemical transformations at high temperatures. Current pyrometallurgical recovery processes primarily rely on roasting followed by leaching. This involves first roasting with the addition of a certain amount of a substance acting as a calcining agent, followed by leaching and separation of the roasted product to yield different products. While pyrometallurgy offers high metal recovery rates, the recovery process is complex and costly. Furthermore, when the recovered metals are used to prepare lithium battery cathode materials, they often suffer from insufficient purity, resulting in poor regeneration of the cathode material.

[0005] In view of this, developing a method for recycling positive electrode materials from waste ternary lithium-ion batteries with a simple process flow and convenient operation has important practical significance for the field of lithium-ion battery recycling technology. Summary of the Invention

[0006] In view of the fact that the existing methods for recovering metals from waste ternary lithium-ion batteries are costly and have complex process flows, and that when the recovered metals are used to prepare positive electrode materials for lithium batteries, the purity is insufficient, resulting in poor results in the regenerated positive electrode materials, the present invention provides a method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A first aspect of the present invention provides a method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries, comprising the following steps:

[0009] Step 1: ball milling the waste ternary lithium-ion battery positive electrode powder to obtain pretreated positive electrode powder;

[0010] Step 2: uniformly mixing the pretreated cathode powder with a ternary deep eutectic solvent, performing microwave-assisted leaching, and filtering to obtain a metal leachate;

[0011] Step 3, adding a reducing crystallizing agent and a first precipitating agent to the metal leachate, filtering to obtain a nickel-cobalt-manganese co-precipitate and a lithium salt solution; adding a second precipitating agent to the lithium salt solution, precipitating at 90-100° C., filtering to obtain a lithium salt precipitate;

[0012] Step 4: adjusting the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese co-precipitate, and performing a primary calcination at 700-800° C. to obtain a primary sintered product; adding the lithium salt precipitate to the primary sintered product, and performing a secondary calcination at 700-850° C. to obtain a regenerated positive electrode material;

[0013] Wherein, the ternary deep eutectic solvent is a mixture of tartaric acid, sorbitol and choline bitartrate.

[0014] The present invention designs a ternary deep eutectic solvent with tartaric acid and sorbitol as hydrogen bond donors and choline bitartrate as a hydrogen bond acceptor. This ternary deep eutectic solvent is a strongly coordinating, low-viscosity acid-based deep eutectic solvent with excellent proton activity and reducing power, enabling efficient and gentle leaching of lithium, nickel, cobalt, and manganese. The ternary deep eutectic solvent can extract high-valent metal elements (cobalt, nickel, and manganese) from the cathode material through complexation, forming high-valent metal complexes. Furthermore, because the metal oxides in the cathode material have excellent microwave absorption properties, microwaves can enhance the extraction efficiency of the metal oxides using the ternary deep eutectic solvent.

[0015] By adding a reducing crystallizer, a high-valent metal can be reduced to a low-valent metal, changing the stability of the metal complex, and converting it into a low-valent metal complex with poor stability, which is easier to combine with the first precipitant to form a nickel-cobalt-manganese co-precipitated lithium salt solution. A second precipitant is then added to the lithium salt solution to obtain a lithium salt precipitate. In order to better regenerate the recovered metal precipitate, the present invention can determine the metal content in the metal leachate, obtain the molar ratio of each metal element by calculation, precipitate the metal in sequence, and then adjust the molar ratio of each metal element in the recovered metal precipitate by supplementing metal oxide and lithium salt precipitation. Combined with the calcination process, a regenerated positive electrode material can be obtained.

[0016] The technical solution designed by the present invention can recycle and regenerate positive electrode materials from waste lithium-ion battery positive electrode materials. Through the waste material-raw material-recycled product process design, the reuse of waste lithium battery positive electrode materials is achieved to the greatest extent. More importantly, the regenerated positive electrode material ultimately provided by the present invention has excellent performance and can be used to prepare regenerated lithium batteries. The technical solution of the present invention effectively solves the problem that the method of recovering metals from waste ternary lithium-ion batteries is high in cost and complex in process flow, and the problem that the recovered metals are insufficiently pure when used to prepare lithium battery positive electrode materials, resulting in poor results of the regenerated positive electrode materials. This provides a new approach to the recycling and reuse of waste lithium battery positive electrode materials.

[0017] Preferably, the molar ratio of tartaric acid, sorbitol and choline bitartrate in the ternary deep eutectic solvent is 0.2:3:1-0.8:5:1.

[0018] Further preferably, the preparation method of the ternary deep eutectic solvent includes the following steps: weighing each raw material component according to the designed ratio, mixing them evenly, and obtaining a deep eutectic solvent precursor; adding deionized water to the deep eutectic solvent precursor, mixing and stirring at 80-100°C until the liquid is colorless and transparent, and obtaining a ternary deep eutectic solvent.

[0019] More preferably, the amount of deionized water added is 10%-15% of the mass of the deep eutectic solvent precursor.

[0020] The viscosity of the deep eutectic solvent represents the difficulty of the components in the system moving to the cavities, which has a great impact on the dissolution efficiency of metal oxides. Too high viscosity is not conducive to the dissolution of metal oxides, thereby reducing their leaching of valuable metal elements. Therefore, the present invention adds deionized water to the deep eutectic solvent precursor to reduce the viscosity of the ternary deep eutectic solvent and improve the leaching rate of the metal oxides by the ternary deep eutectic solvent.

[0021] Preferably, in step 1, the ball milling speed is 500-700 rpm, and the ball milling time is 3-5 h.

[0022] Preferably, in step 2, the mass ratio of the pretreated positive electrode powder to the ternary deep eutectic solvent is 1:30-2:50.

[0023] Preferably, in step 2, the temperature of the microwave-assisted leaching is 70-90° C., and the time of the microwave-assisted leaching is 1-3 h.

[0024] Preferably, in step three, the reducing crystallization agent is a hydrogen peroxide solution with a mass concentration of 50%-65%.

[0025] Preferably, in step three, the first precipitant is a 0.5-1 mol / L oxalic acid solution.

[0026] Preferably, in step three, the second precipitant is a 0.5-1 mol / L sodium carbonate solution.

[0027] Further preferably, the molar ratio of the hydrogen peroxide in the reducing crystallization agent to the total metal amount in the metal leachate is 1:1-2:1.

[0028] Further preferably, the molar ratio of oxalic acid in the first precipitant to the total amount of nickel, cobalt and manganese ions in the metal leachate is 1:1-2:1.

[0029] Further preferably, the molar ratio of sodium carbonate in the second precipitant to lithium ions in the lithium salt solution is 1:1-1.5:1.

[0030] Further preferably, in step 4, the holding time of the first calcination is 2-4 hours.

[0031] Further preferably, in step 4, the holding time of the secondary calcination is 10-12 hours.

[0032] Further preferably, in step 4, the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese co-precipitate is adjusted to 6:2:2.

[0033] The present invention adjusts the molar ratio of lithium, nickel, cobalt and manganese to 1:0.6:0.2:0.2, and combines the calcination process to obtain the regenerated positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O2.

[0034] The second aspect of the present invention provides a regenerated positive electrode material, which is recovered and prepared using the method for recovering regenerated positive electrode materials from waste ternary lithium-ion batteries.

[0035] In summary, the present invention provides a method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries, wherein the waste lithium-ion battery positive electrode materials are efficiently leached by a ternary deep eutectic solvent combined with microwave-assisted leaching, and the positive electrode materials are recovered and regenerated by combining subsequent precipitation and adjusting the molar ratio of metal elements. The recovered and regenerated positive electrode materials have good electrochemical properties. The technical solution provided by the present invention effectively solves the problems of high cost and complicated process flow in the prior art methods for recovering metals from waste ternary lithium-ion batteries, and the problem that when the recovered metals are used to prepare lithium battery positive electrode materials, the purity is insufficient, resulting in poor effect of the regenerated positive electrode materials, and provides a new idea for the treatment of waste ternary lithium-ion batteries. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries, comprising the following steps:

[0039] Step 1: ball mill the waste ternary lithium-ion battery positive electrode powder at a speed of 600 rpm for 4 hours to obtain 50 g of pretreated positive electrode powder;

[0040] Step 2: The pretreated positive electrode powder is evenly mixed with the ternary deep eutectic solvent, subjected to microwave-assisted leaching at 85° C. for 2 h, and filtered to obtain a metal leachate; the content of each metal ion in the metal leachate is determined by inductively coupled plasma atomic emission spectrometry, and the molar ratio of each metal element is calculated to be nickel: cobalt: manganese: lithium = 7.9:1.6:1.7:17.2;

[0041] Step 3: adding 1500 mL of 60% hydrogen peroxide solution and 200 mL of 1 mol / L oxalic acid solution to the metal leachate, letting it stand for 12 hours, and filtering to obtain a nickel-cobalt-manganese co-precipitate and a lithium salt solution; adding 250 mL of 1 mol / L sodium carbonate solution to the lithium salt solution, letting it stand at 95° C. for 8 hours, filtering the precipitate to obtain a lithium salt precipitate;

[0042] Step 4: Add 1.9g of cobalt oxalate and 1.3g of manganese oxalate to adjust the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese coprecipitate to 6:2:2, and calcine once at 700°C for 3 hours to obtain a primary sintered product; add 76.5% of the lithium salt precipitate to the primary sintered product, calcine twice at 750°C for 12 hours to obtain the regenerated positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O2.

[0043] Among them, the ternary deep eutectic solvent is a mixture of tartaric acid, sorbitol and choline bitartrate with a molar ratio of 0.5:4:1. The specific preparation method includes the following steps: weighing 90g of tartaric acid, 874g of sorbitol and 304g of choline bitartrate according to the designed ratio, mixing them evenly to obtain a deep eutectic solvent precursor; adding 155g of deionized water to the deep eutectic solvent precursor, mixing and stirring at 90°C until the liquid is colorless and transparent, to obtain a ternary deep eutectic solvent.

[0044] Example 2

[0045] This embodiment provides a method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries, comprising the following steps:

[0046] Step 1: ball mill the waste ternary lithium-ion battery positive electrode powder at a speed of 500 rpm for 4 hours to obtain 50 g of pretreated positive electrode powder;

[0047] Step 2: The pretreated positive electrode powder is evenly mixed with the ternary deep eutectic solvent, subjected to microwave-assisted leaching at 75° C. for 3 h, and filtered to obtain a metal leachate; the content of each metal ion in the metal leachate is determined by inductively coupled plasma atomic emission spectrometry, and the molar ratio of each metal element is calculated to be nickel: cobalt: manganese: lithium = 9.2:3.1:3.7:19.9;

[0048] Step 3: Add 1500 mL of 55% hydrogen peroxide solution and 350 mL of 0.8 mol / L oxalic acid solution to the metal leachate, let it stand for 12 hours, and filter to obtain a nickel-cobalt-manganese co-precipitate and a lithium salt solution; add 210 mL of 1 mol / L sodium carbonate solution to the lithium salt solution, let it stand at 95° C. for 8 hours, filter the precipitate, and obtain a lithium salt precipitate;

[0049] Step 4: Add 2.78g of nickel oxalate and 1.1g of cobalt oxalate to adjust the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese coprecipitate to 6:2:2, calcinate once at 720°C, keep warm for 3h, and obtain a primary sintered product; add 92.7% of the lithium salt precipitate to the primary sintered product, calcine twice at 800°C, keep warm for 12h, and obtain the regenerated positive electrode material LiNi 0.6 Co0.2 Mn 0.2 O2.

[0050] Among them, the ternary deep eutectic solvent is a mixture of tartaric acid, sorbitol and choline bitartrate with a molar ratio of 0.5:4:1. The specific preparation method includes the following steps: weighing 90g of tartaric acid, 874g of sorbitol and 304g of choline bitartrate according to the designed ratio, mixing them evenly to obtain a deep eutectic solvent precursor; adding 155g of deionized water to the deep eutectic solvent precursor, mixing and stirring at 90°C until the liquid is colorless and transparent, to obtain a ternary deep eutectic solvent.

[0051] Example 3

[0052] This embodiment provides a method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries, comprising the following steps:

[0053] Step 1: ball mill the waste ternary lithium-ion battery positive electrode powder at a speed of 700 rpm for 4 hours to obtain 50 g of pretreated positive electrode powder;

[0054] Step 2: The pretreated positive electrode powder is evenly mixed with the ternary deep eutectic solvent, subjected to microwave-assisted leaching at 90° C. for 1 hour, and filtered to obtain a metal leachate; the content of each metal ion in the metal leachate is determined by inductively coupled plasma atomic emission spectrometry, and the molar ratio of each metal element is calculated to be nickel: cobalt: manganese: lithium = 8.5:2.9:2.3:18.6;

[0055] Step 3: Add 1500 mL of 60% hydrogen peroxide solution and 250 mL of 1 mol / L oxalic acid solution to the metal leachate, let it stand for 12 hours, and filter to obtain a nickel-cobalt-manganese co-precipitate and a lithium salt solution; add 220 mL of 1 mol / L sodium carbonate solution to the lithium salt solution, let it stand at 95° C. for 8 hours, filter the precipitate, and obtain a lithium salt precipitate;

[0056] Step 4: Add 0.29g nickel oxalate and 0.85g manganese oxalate to adjust the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese coprecipitate to 6:2:2, calcinate once at 760°C, keep warm for 3h, and obtain a primary sintered product; add 78% of the lithium salt precipitate to the primary sintered product, calcine twice at 850°C, keep warm for 12h, and obtain the regenerated positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O2.

[0057] Among them, the ternary deep eutectic solvent is a mixture of tartaric acid, sorbitol and choline bitartrate with a molar ratio of 0.5:4:1. The specific preparation method includes the following steps: weighing 90g of tartaric acid, 874g of sorbitol and 304g of choline bitartrate according to the designed ratio, mixing them evenly to obtain a deep eutectic solvent precursor; adding 155g of deionized water to the deep eutectic solvent precursor, mixing and stirring at 90°C until the liquid is colorless and transparent, to obtain a ternary deep eutectic solvent.

[0058] Comparative Example 1

[0059] This comparative example provides a method for recovering and regenerating positive electrode materials from waste ternary soft-pack lithium batteries. The difference from Example 1 is that the deep eutectic solvent is a mixture of sorbitol and choline chloride, which specifically includes the following contents.

[0060] Step 1: ball mill the waste ternary lithium-ion battery positive electrode powder at a speed of 600 rpm for 4 hours to obtain 50 g of pretreated positive electrode powder;

[0061] Step 2: The pretreated positive electrode powder is evenly mixed with a deep eutectic solvent, subjected to microwave-assisted leaching at 85° C. for 2 h, and filtered to obtain a metal leachate; the content of each metal ion in the metal leachate is determined by inductively coupled plasma atomic emission spectrometry, and the molar ratio of each metal element is calculated to be nickel: cobalt: manganese: lithium = 7.9:1.6:1.7:17.2;

[0062] Step 3: adding 1500 mL of 60% hydrogen peroxide solution and 200 mL of 1 mol / L oxalic acid solution to the metal leachate, letting it stand for 12 hours, and filtering to obtain a nickel-cobalt-manganese co-precipitate and a lithium salt solution; adding 250 mL of 1 mol / L sodium carbonate solution to the lithium salt solution, letting it stand at 95° C. for 8 hours, filtering the precipitate to obtain a lithium salt precipitate;

[0063] Step 4: Add 1.9g of cobalt oxalate and 1.3g of manganese oxalate to adjust the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese coprecipitate to 6:2:2, and calcine once at 700°C for 3 hours to obtain a primary sintered product; add 76.5% of the lithium salt precipitate to the primary sintered product, calcine twice at 750°C for 12 hours to obtain the regenerated positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O2.

[0064] Among them, the ternary deep eutectic solvent is a mixture of sorbitol and choline chloride with a molar ratio of 4:1. The specific preparation method includes the following steps: weighing 874g of sorbitol and 304g of choline chloride according to the designed ratio, mixing them evenly to obtain a deep eutectic solvent precursor; adding 141g of deionized water to the deep eutectic solvent precursor, mixing and stirring at 90°C until the liquid is colorless and transparent, to obtain a ternary deep eutectic solvent.

[0065] Comparative Example 2

[0066] This comparative example provides a method for recovering and regenerating positive electrode materials from waste ternary soft-pack lithium batteries. The difference from Example 1 is that microwave-assisted leaching is not used. Specifically, the method includes the following contents.

[0067] Step 1: ball mill the waste ternary lithium-ion battery positive electrode powder at a speed of 600 rpm for 4 hours to obtain 50 g of pretreated positive electrode powder;

[0068] Step 2: The pretreated positive electrode powder is mixed evenly with the ternary deep eutectic solvent, allowed to stand for 2 hours, and filtered to obtain a metal leachate; the content of each metal ion in the metal leachate is determined by inductively coupled plasma atomic emission spectrometry, and the molar ratio of each metal element is calculated to be nickel: cobalt: manganese: lithium = 7.9:1.6:1.7:17.2;

[0069] Step 3: adding 1500 mL of 60% hydrogen peroxide solution and 200 mL of 1 mol / L oxalic acid solution to the metal leachate, letting it stand for 12 hours, and filtering to obtain a nickel-cobalt-manganese co-precipitate and a lithium salt solution; adding 250 mL of 1 mol / L sodium carbonate solution to the lithium salt solution, letting it stand at 95° C. for 8 hours, filtering the precipitate to obtain a lithium salt precipitate;

[0070] Step 4: Add 1.9g of cobalt oxalate and 1.3g of manganese oxalate to adjust the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese coprecipitate to 6:2:2, and calcine once at 700°C for 3 hours to obtain a primary sintered product; add 76.5% of the lithium salt precipitate to the primary sintered product, calcine twice at 750°C for 12 hours to obtain the regenerated positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O2.

[0071] Among them, the ternary deep eutectic solvent is a mixture of tartaric acid, sorbitol and choline bitartrate with a molar ratio of 0.5:4:1. The specific preparation method includes the following steps: weighing 90g of tartaric acid, 874g of sorbitol and 304g of choline bitartrate according to the designed ratio, mixing them evenly to obtain a deep eutectic solvent precursor; adding 155g of deionized water to the deep eutectic solvent precursor, mixing and stirring at 90°C until the liquid is colorless and transparent, to obtain a ternary deep eutectic solvent.

[0072] In order to further demonstrate the technical effects of the present invention, the present invention tests the regenerated positive electrode materials obtained in Examples 1-3 and Comparative Examples 1-2 and makes them into lithium-ion button batteries, as shown in the test examples.

[0073] Test example

[0074] S1. Evenly mix 0.08 g of the recovered positive electrode material, 0.01 g of acetylene black, 0.01 g of polyvinylidene fluoride, and 2 mL of N-methylpyrrolidone to obtain a positive electrode slurry;

[0075] S2. The positive electrode slurry is coated on aluminum foil to form a positive electrode sheet. In an inert atmosphere, graphite is used as the negative electrode sheet, the electrolyte is an electrolyte containing LiPF6, and the isolation membrane is a ceramic-coated polypropylene / polyethylene (PP / PE) isolation membrane. Assemble and obtain a lithium-ion battery.

[0076] The present invention conducted discharge capacity testing, rate testing, and cycle performance testing on lithium-ion batteries made from the recycled positive electrode materials obtained in each embodiment and comparative example, specifically including the following:

[0077] Discharge capacity test: With a charge / discharge cutoff voltage of 3.0-4.48V and an initial charge / discharge rate of 0.5C, charge the lithium-ion battery at 0.5C to 4.48V, then charge it at a constant voltage to 0.05C, and discharge it at 0.5C to 3.0V. The discharge capacity is the initial discharge capacity. Discharge capacity = initial discharge capacity (mAh) / cathode active material weight (g).

[0078] Rate test: The charge and discharge cut-off voltage is 3.0-4.48V. The lithium-ion battery is charged to 4.48V at 0.5C, then charged to 0.05C at a constant voltage, and then discharged to 3.0V at 2C. The 2C discharge capacity of the lithium-ion battery is obtained. The capacity retention rate of 2C discharge capacity = 2C discharge capacity / 0.5C discharge capacity.

[0079] Cycling performance test: The lithium-ion battery was charged at 0.7C to 4.48V, then charged at a constant voltage to 0.05C, and then discharged at 1C to 3.0V. This process was repeated to record the capacity retention rate of the lithium-ion battery after 500 cycles. The test results are shown in Table 1.

[0080] Table 1 Recycled positive electrode materials LiNi obtained from various examples and comparative examples 0.6 Co 0.2 Mn 0.2 Electrochemical performance test results of lithium-ion button batteries made with O2

[0081]

[0082] It can be seen from Table 1 that the lithium-ion battery prepared by using the recycled positive electrode material from the waste ternary lithium-ion battery provided by the present invention has excellent electrochemical performance, providing a new treatment idea for waste ternary lithium-ion batteries.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries, characterized in that: The steps include: Step 1: ball milling the waste ternary lithium-ion battery positive electrode powder to obtain pretreated positive electrode powder; Step 2: uniformly mixing the pretreated cathode powder with a ternary deep eutectic solvent, performing microwave-assisted leaching, and filtering to obtain a metal leachate; Step 3: adding a reducing crystallizing agent and a first precipitating agent to the metal leachate, filtering, and obtaining a nickel-cobalt-manganese co-precipitate and a lithium salt solution; adding a second precipitant to the lithium salt solution, precipitating at 90-100° C., and filtering to obtain a lithium salt precipitate; Step 4: adjusting the molar ratio of nickel, cobalt and manganese in the nickel-cobalt-manganese co-precipitate, and calcining it once at 700-800° C. to obtain a primary sintered product; adding the lithium salt precipitate to the primary sintered product, and calcining it twice at 700-800° C. to obtain a regenerated positive electrode material; Wherein, the ternary deep eutectic solvent is a mixture of tartaric acid, sorbitol and choline bitartrate; in step three, the reducing crystallization agent is a hydrogen peroxide solution with a mass concentration of 50%-65%.

2. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 1, wherein: The molar ratio of tartaric acid, sorbitol and choline bitartrate in the ternary deep eutectic solvent is 0.2:3:1-0.8:5:

1.

3. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 2, wherein: The preparation method of the ternary deep eutectic solvent comprises the following steps: weighing each raw material component according to the designed ratio, mixing them evenly, and obtaining a deep eutectic solvent precursor; adding deionized water to the deep eutectic solvent precursor, mixing and stirring at 80-100° C. until the liquid becomes colorless and transparent, and obtaining a ternary deep eutectic solvent.

4. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 3, wherein: The amount of deionized water added is 10%-15% of the mass of the deep eutectic solvent precursor.

5. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 1, wherein: In step 1, the ball milling speed is 500-700 rpm, and the ball milling time is 3-5 h.

6. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 1, wherein: In step 2, the mass ratio of the pretreated positive electrode powder to the ternary deep eutectic solvent is 1:30-2:50; and / or In step 2, the temperature of the microwave-assisted leaching is 70-90° C., and the time of the microwave-assisted leaching is 1-3 hours.

7. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 1, wherein: In step 3, the first precipitant is a 0.5-1 mol / L oxalic acid solution; and / or In step 3, the second precipitant is a 0.5-1 mol / L sodium carbonate solution.

8. The method for recovering and regenerating positive electrode materials from waste ternary lithium-ion batteries according to claim 1, wherein: The molar ratio of hydrogen peroxide in the reducing crystallizer to the total metal amount in the metal leachate is 1:1-2:1; and / or The molar ratio of oxalic acid in the first precipitant to the total amount of nickel, cobalt and manganese ions in the metal leachate is 1:1-2:1; and / or The molar ratio of sodium carbonate in the second precipitant to lithium ions in the lithium salt solution is 1:1-1.5:

1.

9. The method for recovering and regenerating cathode materials from waste ternary lithium-ion batteries according to claim 1, wherein: In step 4, the holding time of the first calcination is 2-4 hours; and / or In step 4, the holding time of the secondary calcination is 10-12 hours.

Images