A method for preparing a nickel-cobalt-manganese lithium battery from a retired lithium cobalt oxide and lithium manganate battery cathode material

Abstract

This invention discloses a method for preparing nickel-cobalt-manganese lithium oxide batteries from retired lithium cobalt oxide and lithium manganese oxide battery cathode materials. (1) After pretreatment processes such as discharge, disassembly, crushing, and sieving, retired lithium cobalt oxide and lithium manganese oxide batteries are obtained as cathode materials respectively. (2) The two cathode materials are mixed with NiSO4·7H2O and NiCO3 in a certain proportion and then calcined at high temperature for a period of time. (3) The calcined product obtained in the second step is thoroughly ground and then leached with deionized water to obtain lithium sulfate leachate and ternary precursor (leaching residue). (4) The lithium sulfate leachate is evaporated and concentrated, sodium hydroxide is added to adjust the pH, and then sodium carbonate is added for precipitation to obtain lithium carbonate product. This invention has the characteristics of simple process, green environmental protection and high utilization efficiency. It combines resource recycling with high-performance material regeneration and provides a sustainable solution for the recycling of waste lithium-ion battery cathode materials.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling and mainly relates to a method for preparing nickel-cobalt-manganese lithium oxide batteries using retired lithium cobalt oxide and lithium manganese oxide battery cathode materials. Background Technology

[0002] Lithium-ion batteries (LIBs) are rechargeable batteries that use lithium metal compounds as the positive electrode and graphite as the negative electrode. Their main structure includes electrode materials, Al / Cu current collectors, organic solvents, separators, and casings. With advantages such as high energy density, long cycle life, lightweight design, and low self-discharge, lithium-ion batteries have gradually replaced lead-acid and alkaline batteries, and are widely used in electronic devices and new energy vehicles. Statistics from the Ministry of Industry and Information Technology show that my country's lithium-ion battery production reached 1170 GWh in 2024, with a total industry output value exceeding 1.2 trillion yuan. It is estimated that by 2030, global lithium-ion battery production will reach 6.5 TWh, with China accounting for more than half. However, after multiple charge-discharge cycles, the electrode material structure of lithium-ion batteries will be damaged, leading to battery capacity decay. When the capacity decays to 70% to 80% of its initial value, the battery needs to be replaced. The lifespan of a lithium-ion battery is generally 5 to 8 years, which means that large-scale application will generate a massive amount of waste lithium-ion batteries.

[0003] Waste lithium-ion batteries contain toxic and flammable components such as heavy metals, lithium hexafluorophosphate, and polyvinylidene fluoride. Improper landfill management can lead to serious environmental pollution and safety hazards. On the other hand, waste lithium-ion batteries contain large amounts of valuable metals such as Ni, Co, Mn, Li, and Al, with the metal content in the cathode material far exceeding the average grade in natural ores, earning them the moniker of "urban mines." Therefore, recycling waste lithium-ion batteries, especially cathode materials, is of great significance for alleviating resource shortages and promoting sustainable industrial development.

[0004] Current methods for recycling spent lithium-ion batteries include pyrometallurgy, hydrometallurgy, combined pyrometallurgical and hydrometallurgical processes, and battery regeneration technologies. Extensive research has been conducted on both pyrometallurgical and hydrometallurgical recycling processes for spent lithium-ion batteries. Pyrometallurgical processes are simple to operate and highly compatible, but consume a lot of energy and produce large emissions; hydrometallurgical processes have high recovery rates, but the cost of reducing agents is high and the separation process is complex. Neither pyrometallurgical nor hydrometallurgical processes alone can meet the demands of green development due to their unavoidable drawbacks. Therefore, combined pyrometallurgical and hydrometallurgical processes, which combine the advantages of both methods, have emerged. In these processes, the spent cathode material is first roasted at a relatively high temperature, converting valuable metals into water-soluble salts to simplify the subsequent leaching process and reduce toxic gas emissions, achieving a better balance between recycling efficiency, energy consumption, and economics. Combined processes can be categorized by the type of additives used, such as sulfation roasting, chlorination roasting, and nitration roasting. Sulfation roasting involves co-roasting waste cathode materials with SO2, sulfuric acid, or sulfates to selectively convert metals into water-soluble sulfates, followed by efficient separation and recovery through water leaching. For example, CN118851215A discloses a method for sulfation of waste lithium cobalt oxide cathode materials using pyrite, followed by water leaching to separate lithium-containing solutions and iron-cobalt sulfides, which are subsequently recovered via lithium carbonate and non-ferrous smelting, respectively. Patent CN120174199A mentions using concentrated sulfuric acid to sulfate and roast waste cathode materials, followed by water leaching to obtain lithium extraction slag and a lithium-rich solution. Focusing on the lithium extraction slag, it utilizes the complexation reaction of ammonium salts and reducing agents to extract valuable metals, uses hydrogen peroxide to remove impurities, and ultimately recovers valuable metals, providing an exploratory solution for the commercial application of sulfation roasting technology. However, while the above technologies achieve comprehensive recycling of waste cathode materials, product purity is difficult to guarantee, and the products have not been used in the battery industry, failing to achieve the goal of promoting industrial recycling.

[0005] Battery regeneration is an emerging solution for recycling spent batteries. It primarily involves structural repair and lithium replenishment of spent cathode materials through methods such as solid-state sintering, co-precipitation, and hydrothermal sintering, directly yielding recycled cathode materials. Patent CN121183137A discloses a regeneration process that uses a hydrothermal method to replenish lithium in spent lithium manganese oxide materials, followed by high-temperature sintering for structural repair. Additionally, there are methods that utilize external strengthening fields to promote structural repair and improve material performance. For example, patent CN115764041A mentions a technique for repairing and modifying spent lithium cobalt oxide cathode materials using high-temperature solid-state sintering. Under the influence of PVP and ultrasonic-assisted technology, the layered structure of the spent cathode material is repaired, and a thin spinel coating is formed, improving the high-voltage resistance of the recycled material. Patent CN121307274A mentions the ability to obtain a eutectic molten salt of cathode material and lithium salt using high temperature, and to utilize ultrasonic-induced cavitation to promote lithium... +Rapid diffusion enables efficient lithium replenishment. This type of process can yield high-performance recycled cathode materials, but it has stringent requirements for raw material purity and is difficult to operate, making it unsuitable for large-scale applications.

[0006] In summary, exploring a simple and efficient method for the regeneration and comprehensive utilization of spent lithium-ion battery cathode materials is crucial. This study employs the following method: spent lithium cobalt oxide and lithium manganese oxide cathode materials are treated with sulfation roasting, followed by water leaching to obtain a lithium-containing solution and high-purity nickel-cobalt-manganese oxides. The lithium-containing solution is then concentrated through evaporation and chemical precipitation to obtain lithium carbonate. Subsequently, the lithium carbonate and nickel-cobalt-manganese oxides are thoroughly mixed and then solid-state sintered to obtain regenerated ternary cathode materials, achieving efficient utilization of metal elements and regeneration of the cathode material. This process utilizes sulfation roasting and water leaching in the front end, resulting in high separation efficiency and minimal environmental impact, reducing the need for pretreatment in the regeneration process. By fully utilizing the metal resources in the cathode material, the amount of additives required for lithium replenishment can be reduced, further lowering costs. The entire process is simple to operate and ultimately yields regenerated ternary cathode materials with excellent electrochemical performance, contributing to the realization of internal recycling within the battery industry. Summary of the Invention

[0007] This invention addresses the problem of recycling and processing retired lithium cobalt oxide and lithium manganese oxide battery cathode materials by providing a method for preparing nickel-cobalt-manganese lithium oxide batteries from retired lithium cobalt oxide and lithium manganese oxide battery cathode materials.

[0008] The method for synthesizing lithium nickel cobalt manganese oxide from retired lithium cobalt oxide and lithium manganese oxide battery cathode materials of the present invention comprises the following process steps: 1. Pretreatment of waste lithium-ion batteries Lithium cobalt oxide and lithium manganese oxide cathode materials are obtained by pre-processing waste lithium-ion batteries through discharge, dismantling, crushing and screening. 2. Sulphation roasting of waste mixed cathode materials The pretreated lithium cobalt oxide and lithium manganese oxide cathode materials were mixed in a molar ratio of 4:4 to 4:1 to obtain a mixed cathode material. The raw materials were weighed according to a molar ratio of mixed cathode material to NiSO4·7H2O of 1:1 to 3:1 and a molar ratio of mixed cathode material to NiCO3 of 2:1 to 1:2. After thorough grinding, the raw materials were calcined at a high temperature of 300 to 750°C for 5 to 210 minutes and then cooled in the furnace to obtain the calcined product. 3. Water immersion and filtration of the roasted products After thoroughly grinding the calcined product obtained in step 2, deionized water was added at a solid-liquid ratio of 40-70 g / L, and leaching was carried out at 70-90°C for 50-80 min. After filtration, a ternary precursor (leaching residue) and a lithium-rich solution (leaching solution) were obtained. 4. Concentration and precipitation of lithium-containing solutions The leachate obtained in step 3 was evaporated and concentrated to obtain a lithium-rich mother liquor. Sodium hydroxide was then added to adjust the pH to 10-12, and the concentration was adjusted by molar ratio of Li... + CO3 2- After adding sodium carbonate at a ratio of 1:1.2, lithium carbonate is precipitated. 5. High-temperature synthesis of recycled cathode materials The ternary precursor from step 3 and lithium carbonate from step 4 were thoroughly mixed at a molar ratio of Li:(Ni+Co+Mn)=1.05:1, and then calcined at 480°C for 5 h, followed by calcination at 780°C for 12 h for high-temperature solid-state synthesis. The calcined product was then ground and dried to obtain the regenerated ternary cathode material.

[0009] The above method utilizes the ion exchange reaction between nickel sulfate and the mixed cathode material, as well as the gas-solid reaction involving SO2 generated from the decomposition of nickel sulfate under experimental conditions, to achieve the sulfation of the mixed cathode material. This ultimately converts lithium into water-soluble lithium sulfate, while nickel, cobalt, and manganese enter the oxide slag (ternary precursor). In this process, NiSO4·7H2O acts as both a sulfation aid and a Ni-adding agent. Furthermore, by adjusting the molar ratio of the two cathode materials, the proportion of Co and Mn in the ternary precursor can be controlled. Adjusting the amount of NiCO3 added can further control the proportion of Ni in the product. Ultimately, all transition metal elements enter the precursor, while Li enters the solution for recovery, achieving full utilization of all metals. Subsequently, the obtained precursor is mixed with lithium carbonate and calcined at high temperature to obtain the regenerated cathode material.

[0010] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention provides a new method for recycling and reusing waste lithium cobalt oxide and lithium manganese oxide mixed cathode materials. The obtained ternary precursor can be directly used for the regeneration of cathode materials and has good battery capacity and cycle stability; (2) The present invention makes full use of all metal elements in waste cathode materials and additives, without introducing impurities, and at the same time maximizes utilization efficiency; (3) The present invention provides a low-cost, green and short process route for the recycling and reuse of waste lithium cobalt oxide and lithium manganese oxide battery cathode materials, and provides a new idea for realizing the internal circulation of the battery industry. Attached Figure Description

[0011] Figure 1 This is a process flow diagram of the present invention. Figure 2 XRD of the prepared regenerated ternary cathode material Detailed Implementation

[0012] The present invention will be described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0013] Example 1 (1) Two cathode materials were obtained after discharge, calcination, disassembly and grinding. Lithium cobalt oxide and lithium manganese oxide were mixed in a molar ratio of 4:4. The raw materials were weighed according to the molar ratio of mixed cathode material to NiSO4·7H2O of 1:1 and the molar ratio of mixed cathode material to NiCO3 of 2:1. After thorough grinding, the mixture was heated at 10°C·min. -1 The heating rate was increased to 750°C and calcined for 210 min. After cooling in the furnace, the calcined product was obtained.

[0014] (2) After the calcined product obtained in step 1 is thoroughly ground, it is mixed with deionized water at a solid-liquid ratio of 70 g / L, and then leached at 70°C for 80 min. After negative pressure filtration, the leachate and leaching residue are obtained. Under these conditions, the Li leaching rate is about 98.92%.

[0015] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH to 10-12, and then proceed according to Li + CO3 2- Add sodium carbonate at a ratio of 1:1.2 to precipitate lithium carbonate.

[0016] (4) The lithium carbonate obtained in step 3 and the leaching residue obtained in step 2 are mixed at a molar ratio of Li:(Ni+Co+Mn)=1.05:1, and then calcined at 480°C for 5h and then calcined at 780°C for 12h to obtain the calcined product. The product is then ground and thoroughly dried to obtain the regenerated ternary cathode material.

[0017] Example 2 (1) Two cathode materials were obtained after discharge, calcination, disassembly and grinding. Lithium cobalt oxide and lithium manganese oxide were mixed in a molar ratio of 4:1. The raw materials were weighed according to the molar ratio of mixed cathode material to NiSO4·7H2O of 3:1 and the molar ratio of mixed cathode material to NiCO3 of 1:2. After thorough grinding, the mixture was heated at 10°C·min. -1 The temperature was increased to 300°C and calcined for 5 minutes. After cooling in the furnace, the calcined product was obtained.

[0018] (2) After grinding the calcined product obtained in step 1, it is mixed with deionized water at a solid-liquid ratio of 40 g / L, and then leached at 90°C for 50 min. After filtration under negative pressure, the leachate and leaching residue are obtained. Under these conditions, the Li leaching rate is about 98.15%.

[0019] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH to 10-12, and then proceed according to Li + CO3 2- Add sodium carbonate at a ratio of 1:1.2 to precipitate lithium carbonate.

[0020] (4) The lithium carbonate obtained in step 3 and the leaching residue obtained in step 2 are mixed at a molar ratio of Li:(Ni+Co+Mn)=1.05:1, and then calcined at 480°C for 5h and then calcined at 780°C for 12h to obtain the calcined product. The product is then ground and thoroughly dried to obtain the regenerated ternary cathode material.

[0021] Example 3 (1) Two cathode materials were obtained after discharge, calcination, disassembly and grinding. Lithium cobalt oxide and lithium manganese oxide were mixed in a molar ratio of 4:3. The raw materials were weighed according to the molar ratio of mixed cathode material to NiSO4·7H2O of 2:1 and the molar ratio of mixed cathode material to NiCO3 of 1:1. After thorough grinding, the mixture was heated at 10°C·min. -1 The heating rate was increased to 550°C and calcined for 180 min. After cooling in the furnace, the calcined product was obtained.

[0022] (2) After the calcined product obtained in step 1 is thoroughly ground, it is mixed with deionized water at a solid-liquid ratio of 70 g / L, and then leached at 80°C for 60 min. After negative pressure filtration, leachate and leaching residue are obtained. Under these conditions, the Li leaching rate is about 98.65%.

[0023] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH to 10-12, and then proceed according to Li + CO3 2- Add sodium carbonate at a ratio of 1:1.2 to precipitate lithium carbonate.

[0024] (4) The lithium carbonate obtained in step 3 and the leaching residue obtained in step 2 are mixed at a molar ratio of Li:(Ni+Co+Mn)=1.05:1, and then calcined at 480°C for 5h and then calcined at 780°C for 12h to obtain the calcined product. The product is then ground and thoroughly dried to obtain the regenerated ternary cathode material.

[0025] Example 4 (1) Two cathode materials were obtained after discharge, calcination, disassembly and grinding. Lithium cobalt oxide and lithium manganese oxide were mixed in a molar ratio of 4:2. The raw materials were weighed according to the molar ratio of mixed cathode material to NiSO4·7H2O of 1.5:1 and the molar ratio of mixed cathode material to NiCO3 of 1:1. After thorough grinding, the mixture was heated at 10°C·min. -1 The heating rate was increased to 650°C and calcined for 150 min. After cooling in the furnace, the calcined product was obtained.

[0026] (2) After the calcined product obtained in step 1 is thoroughly ground, it is mixed with deionized water at a solid-liquid ratio of 70 g / L, and then leached at 70°C for 70 min. After negative pressure filtration, the leachate and leaching residue are obtained. Under these conditions, the Li leaching rate is about 99.36%.

[0027] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH to 10-12, and then proceed according to Li + CO3 2- Add sodium carbonate at a ratio of 1:1.2 to precipitate lithium carbonate.

[0028] (4) The lithium carbonate obtained in step 3 and the leaching residue obtained in step 2 are mixed at a molar ratio of Li:(Ni+Co+Mn)=1.05:1, and then calcined at 480°C for 5h and then calcined at 780°C for 12h to obtain the calcined product. The product is then ground and thoroughly dried to obtain the regenerated ternary cathode material.

Claims

1. A method for preparing nickel-cobalt-manganese lithium oxide batteries using retired lithium cobalt oxide and lithium manganese oxide battery cathode materials, characterized in that, Includes the following steps: Step 1: The waste lithium cobalt oxide and lithium manganese oxide batteries are subjected to pretreatment processes such as discharge, dismantling, crushing and screening to obtain lithium cobalt oxide and lithium manganese oxide cathode materials. These materials are then mixed with nickel sulfate (NiSO4·7H2O) and nickel carbonate (NiCO3) at a certain molar ratio and then calcined at a certain temperature and time. Step 2: After grinding the calcined product thoroughly, deionized water is added at a certain solid-liquid ratio for leaching for a period of time. After filtering the leachate, a ternary precursor (leaching residue) and a lithium sulfate solution (leaching solution) are obtained. Step 3: Evaporate and concentrate the leachate to obtain lithium-rich mother liquor, then add sodium hydroxide to adjust the pH to 10-12, while simultaneously adding the appropriate amount of lithium by molar ratio. + CO3 2- After adding sodium carbonate at a ratio of 1:1.2, lithium carbonate is precipitated. Step 4: The ternary precursor from Step 2 and lithium carbonate from Step 3 are thoroughly mixed at a molar ratio of Li:(Ni+Co+Mn)=1.05:

1. The mixture is then calcined at 480°C for 5 hours and then at 780°C for 12 hours for high-temperature solid-state synthesis. The calcined product is then ground and dried to obtain the regenerated ternary cathode material.

2. The method for preparing nickel-cobalt-manganese lithium oxide batteries using the retired lithium cobalt oxide and lithium manganese oxide battery cathode materials according to claim 1, characterized in that... The molar ratio of lithium cobalt oxide to lithium manganese oxide cathode material in step 1 is 4:4 to 4:

1.

3. The method for preparing nickel-cobalt-manganese lithium oxide batteries using the retired lithium cobalt oxide and lithium manganese oxide battery cathode materials according to claim 1, characterized in that... The roasting temperature in step 1 is 300~750°C.

4. The method for preparing nickel-cobalt-manganese lithium oxide batteries using the retired lithium cobalt oxide and lithium manganese oxide battery cathode materials according to claim 1, characterized in that... The molar ratio of the mixed cathode material and nickel sulfate mentioned in step 1 is 1:1 to 3:1, and the molar ratio of the mixed cathode material and nickel carbonate is 2:1 to 1:

2.

5. The method for preparing nickel-cobalt-manganese lithium oxide batteries using the retired lithium cobalt oxide and lithium manganese oxide battery cathode materials according to claim 1, characterized in that... The roasting time in step 1 is 5 to 210 minutes.

6. The method for preparing nickel-cobalt-manganese lithium oxide batteries using the retired lithium cobalt oxide and lithium manganese oxide battery cathode materials according to claim 1, characterized in that... The solid-liquid ratio in step 2 is 40~70 g / L, the leaching temperature is 70~90°C, and the leaching time is 50~80 min.

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