Method for synthesizing positive electrode material of nickel cobalt lithium manganate battery from positive electrode material of retired lithium cobalt oxide battery

Abstract

The invention discloses a method for preparing a nickel cobalt lithium manganate battery positive electrode material from a decommissioned lithium cobalt oxide battery positive electrode material lithium cobalt oxide. The method comprises the following steps: (1) carrying out pretreatment processes such as discharging, disassembling, crushing and screening on a decommissioned lithium cobalt oxide battery to obtain a lithium cobalt oxide positive electrode material; (2) mixing the lithium cobalt oxide positive electrode material with NiSO4. 7H2O and MnSO4.H2O according to a certain proportion, and roasting at high temperature for a period of time; (3) fully grinding the roasted product obtained in the step (2), and adding deionized water for leaching to obtain a lithium sulfate leaching solution and a ternary precursor (leaching residue); (4) evaporating and concentrating the lithium sulfate leachate, adding sodium hydroxide to adjust the pH value, and then adding sodium carbonate to precipitate to obtain a lithium carbonate product; and (5) fully mixing lithium carbonate with the precursor obtained in the step (3) according to a certain proportion, and then obtaining the nickel cobalt lithium manganate positive electrode material by utilizing a high-temperature solid-phase synthesis method. The method has the characteristics of low production cost, simple operation, environmental protection and easy separation, combines resource recovery with high-performance material regeneration, and provides a sustainable solution for recovery of the waste lithium cobalt oxide battery positive electrode material.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling and mainly relates to a method for synthesizing lithium nickel cobalt manganese oxide cathode material from retired lithium cobalt oxide battery cathode material. Background Technology

[0002] Lithium-ion batteries (LIBs) are a type of rechargeable battery that uses lithium metal compounds as the positive electrode and graphite as the negative electrode. Due to their high energy density, long battery life, and high safety performance, they have gradually replaced lead-acid and alkaline batteries and are widely used in portable electronic devices and the new energy vehicle industry. 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. 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 the initial capacity, it needs to be replaced. This also means that the increasing production of lithium-ion batteries year by year will be accompanied by a significant increase in the number of waste lithium batteries. It is estimated that the total amount of retired LIBs globally will reach 11 million tons between 2019 and 2030, of which lithium cobalt oxide (LiCoO2 / LCO) batteries will account for more than 20%.

[0003] Waste lithium-ion batteries contain various toxic and hazardous substances, which, if not properly disposed of, can cause serious environmental pollution and safety hazards. On the other hand, waste lithium-ion batteries contain large amounts of valuable metal resources such as Ni, Co, Mn, and Li, and the content of these metals in the cathode materials is much higher than the average grade in natural ores, making them highly valuable for recycling. 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 LiCoO2 batteries include traditional pyrometallurgical and hydrometallurgical processes, as well as novel direct regeneration methods. While pyrometallurgical and hydrometallurgical recycling processes for spent LiCoO2 batteries have been extensively studied, the inherent limitations of each process restrict further development. Therefore, a combined pyrometallurgical-hydrometallurgical process has emerged. In this process, the spent LiCoO2 cathode material is first roasted at a relatively high temperature, causing valuable metals to transform into their corresponding salts. Li and Co are then extracted into a solution through water leaching, followed by recovery through extraction and stepwise precipitation. The combined process mainly includes sulfation roasting, chlorination roasting, and nitration roasting. Sulfation roasting converts lithium and transition metals in the spent LiCoO2 cathode material into corresponding sulfates or metal oxides, which are then separated through water leaching, stepwise precipitation, and extraction, ultimately recovering the majority of Co and Li. For example, patent CN115584393B discloses a method for recovering spent lithium cobalt oxide cathode material and preparing cobalt ferrite through sulfation roasting. The calcined product, after water leaching and filtration, yields cobalt ferrite filter residue and lithium-containing filtrate. These are then modified and precipitated to obtain lithium carbonate and SCR catalyst, respectively. Patent CN118405731A describes a method for immersing cobalt-containing cathode material in CaCl solution for ion exchange and adsorption, followed by drying to obtain a high-performance water electrolysis catalyst. While the above technologies achieve comprehensive recycling of waste cathode materials, product purity is difficult to guarantee, and the products cannot be used in the battery industry, thus failing to promote industrial recycling.

[0005] Direct regeneration is a novel recycling process for waste LiCoO2 batteries. It primarily involves structural repair and lithium replenishment of waste cathode materials through solid-state sintering, co-precipitation, and hydrothermal methods to directly obtain recycled cathode materials. High-temperature solid-state synthesis is one commonly used direct regeneration method. Waste LiCoO2 cathode materials are uniformly mixed with lithium and carbon sources and then calcined at high temperatures to repair the original crystal structure and restore the cathode material's performance. However, direct regeneration processes often place high demands on the precision of pretreatment and the purity of raw materials. For example, patent CN115764041A discloses a technology for regenerating waste lithium cobalt oxide cathode materials using a solid-state repair method. The pretreated cathode material undergoes lithium replenishment and LNMO (LiNi) in a PVP solution and ultrasonic field. 0.5 Mn 1.5 Modified and regenerated LNMO-SLCO material was obtained by coating with O4 material. This product exhibits good electrochemical performance, but it requires high-level pretreatment and the process is difficult to operate, which is not conducive to large-scale application.

[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 LiCoO2 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 concentrated through evaporation, pH adjustment, and precipitation to obtain lithium carbonate. Subsequently, using the obtained lithium carbonate as a lithium source, it is thoroughly mixed with the nickel-cobalt-manganese oxides and then roasted at high temperature to obtain regenerated ternary cathode materials, achieving effective utilization of metal elements in spent LiCoO2 batteries and direct regeneration of the cathode materials. This process uses sulfation roasting and water leaching as separation steps, resulting in high separation efficiency and minimal environmental impact. By fully utilizing the metal resources in the lithium cobalt oxide 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 cathode materials from retired lithium cobalt oxide batteries by providing a method for synthesizing lithium nickel cobalt manganese oxide from retired lithium cobalt oxide battery cathode materials.

[0008] The method for synthesizing lithium nickel cobalt manganese oxide from retired lithium cobalt oxide battery cathode materials according to the present invention comprises the following steps: 1. Pretreatment of waste lithium cobalt oxide batteries Lithium cobalt oxide cathode material is obtained by pre-processing waste lithium cobalt oxide batteries through discharge, dismantling, crushing, and screening. 2. Sulphation roasting of waste LiCoO2 cathode materials NiSO4·7H2O and MnSO4·H2O were mixed in a molar ratio of 1:3 to 3:1 to obtain a mixed sulfate; the pretreated lithium cobalt oxide cathode material was mixed with the mixed sulfate in a molar ratio of 1:0.4 to 1:2 and then thoroughly ground. Subsequently, it was calcined at a high temperature of 300 to 800°C for 30 to 240 minutes and 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 lithium-rich mother liquor. Sodium hydroxide was then added to adjust the pH to 10-12, and sodium carbonate was added to precipitate lithium carbonate. 5. High-temperature synthesis of recycled cathode materials After thoroughly mixing the ternary precursor from step 3 with the lithium carbonate from step 4 in a certain proportion, solid-state synthesis was carried out by calcination at 700~900°C for 5~15 hours. Subsequently, the calcined product was ground and dried to obtain the regenerated ternary cathode material.

[0009] The above method utilizes nickel sulfate, manganese sulfate, and SO2 generated by thermal decomposition to sulfatate lithium cobalt oxide cathode material, converting lithium into the corresponding sulfates, while nickel and manganese enter the oxide slag, thus achieving compositional control of the precursor. Subsequently, lithium replenishment is achieved through high-temperature solid-state synthesis to obtain 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 the cathode material of waste lithium cobalt oxide batteries. The obtained ternary precursor can be directly used for the regeneration of cathode material and has good battery capacity and cycle stability; (2) The present invention makes full use of all metal elements of waste lithium cobalt oxide cathode material to realize the internal circulation of the battery industry; (3) The present invention provides a low-cost, green and short process route for the recycling and reuse of waste lithium cobalt oxide cathode material, and provides a new path for the recycling and reuse of waste lithium cobalt oxide batteries. 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) After discharge, calcination, disassembly and grinding, lithium cobalt oxide cathode material was obtained and mixed with nickel sulfate (NiSO4·7H2O) and manganese sulfate (MnSO4·H2O). The molar ratio of nickel sulfate to manganese sulfate was controlled at 1:3, and the molar ratio of lithium cobalt oxide to sulfate was controlled at 1:2. The mixture was heated at 10°C·min. -1 The heating rate was increased to 300°C and calcined for 240 minutes. After cooling in the furnace, the calcined product was obtained.

[0014] (2) The calcined product obtained in step 1 was 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, leachate and leach residue were obtained.

[0015] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH, 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 in a suitable ratio (Li:(Ni+Co+Mn)=1.05:1) and then calcined at 700°C for 12h to obtain the calcined product. Then, the product is ground and dried thoroughly to obtain the regenerated ternary cathode material.

[0017] Example 2 (1) After discharge, calcination, disassembly and grinding, lithium cobalt oxide cathode material was obtained and mixed with nickel sulfate (NiSO4·7H2O) and manganese sulfate (MnSO4·H2O). The molar ratio of nickel sulfate to manganese sulfate was controlled at 3:1 and the molar ratio of lithium cobalt oxide to sulfate was controlled at 1:1. The mixture was heated at 10°C·min -1 The temperature was increased to 800°C and calcined for 30 minutes. After cooling in the furnace, the calcined product was obtained.

[0018] (2) The calcined product obtained in step 1 was mixed with deionized water at a solid-liquid ratio of 40 g / L, and then leached at 80°C for 50 min. After filtration under negative pressure, leachate and leach residue were obtained.

[0019] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH, 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 in a suitable ratio (Li:(Ni+Co+Mn)=1.05:1) and then calcined at 900°C for 5 hours to obtain the calcined product. Then, the product is ground and dried thoroughly to obtain the regenerated ternary cathode material.

[0021] Example 3 (1) After discharge, calcination, disassembly and grinding, lithium cobalt oxide cathode material was obtained and mixed with nickel sulfate (NiSO4·7H2O) and manganese sulfate (MnSO4·H2O). The molar ratio of nickel sulfate and manganese sulfate was controlled to be 1:1, and the molar ratio of lithium cobalt oxide to sulfate was controlled to be 1:0.4. The mixture was heated at 10°C·min. -1 The heating rate was increased to 600°C and calcined for 120 minutes. After cooling in the furnace, the calcined product was obtained.

[0022] (2) The calcined product obtained in step 1 was mixed with deionized water at a solid-liquid ratio of 70 g / L, and then leached at 90°C for 60 min. After negative pressure filtration, leachate and leach residue were obtained.

[0023] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH, 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 in a suitable ratio (Li:(Ni+Co+Mn)=1.05:1) and then calcined at 800°C for 15h to obtain the calcined product. Then, the product is ground and dried thoroughly to obtain the regenerated ternary cathode material.

[0025] Example 4 (1) After discharge, calcination, disassembly and grinding, lithium cobalt oxide cathode material was obtained and mixed with nickel sulfate (NiSO4·7H2O) and manganese sulfate (MnSO4·H2O). The molar ratio of nickel sulfate to manganese sulfate was controlled at 1:2, and the molar ratio of lithium cobalt oxide to sulfate was controlled at 1:0.6. The mixture was heated at 10°C·min. -1 The heating rate was increased to 600°C and calcined for 210 minutes. After cooling in the furnace, the calcined product was obtained.

[0026] (2) The calcined product obtained in step 1 was mixed with deionized water at a solid-liquid ratio of 70 g / L, and then leached at 90°C for 60 min. After negative pressure filtration, leachate and leach residue were obtained.

[0027] (3) Evaporate and concentrate the leachate obtained in step 2, add NaOH to adjust the pH, 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 in a suitable ratio (Li:(Ni+Co+Mn)=1.05:1) and then calcined at 750°C for 15h to obtain the calcined product. Then, the product is ground and dried thoroughly to obtain the regenerated ternary cathode material.

Claims

1. A method for synthesizing lithium nickel cobalt manganese oxide from retired lithium cobalt oxide battery cathode materials, characterized in that, Includes the following steps: Step 1: The waste lithium cobalt oxide batteries are pre-treated by discharging, dismantling, crushing and screening to obtain lithium cobalt oxide cathode material, which is then mixed with nickel sulfate (NiSO4·7H2O) and manganese sulfate (MnSO4·H2O) in 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, and add sodium carbonate to precipitate lithium carbonate. Step 4: After thoroughly mixing the ternary precursor from Step 2 with the lithium carbonate from Step 3 in a certain proportion, high-temperature solid-state synthesis is carried out at a certain temperature and time. Subsequently, the calcined product is ground and thoroughly dried to obtain the regenerated ternary cathode material.

2. The method for synthesizing lithium nickel cobalt manganese oxide from the cathode material of decommissioned lithium cobalt oxide batteries according to claim 1, characterized in that... The roasting temperature in step 1 is 300~800°C.

3. The method for synthesizing lithium nickel cobalt manganese oxide from the cathode material of decommissioned lithium cobalt oxide batteries according to claim 1, characterized in that... The molar ratio of nickel sulfate and manganese sulfate mentioned in step 1 is 1:3 to 3:

1.

4. The method for synthesizing lithium nickel cobalt manganese oxide from the cathode material of decommissioned lithium cobalt oxide batteries according to claim 1, characterized in that... The molar ratio of lithium cobalt oxide and mixed sulfate in the raw materials before roasting in step 1 is 1:0.4 to 1:

2.

5. The method for synthesizing lithium nickel cobalt manganese oxide from the cathode material of decommissioned lithium cobalt oxide batteries according to claim 1, characterized in that... The roasting time mentioned in step 1 is 30~240 min.

6. The method for synthesizing lithium nickel cobalt manganese oxide from the cathode material of decommissioned lithium cobalt oxide batteries 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.

7. The method for synthesizing lithium nickel cobalt manganese oxide from the cathode material of decommissioned lithium cobalt oxide batteries according to claim 1, characterized in that... The solid-phase synthesis temperature in step 4 is 700~900°C, and the calcination time is 5~15h.

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