A method for regenerating waste ternary positive electrode material and regenerated ternary positive electrode material
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEFEI GUOXUAN HIGH TECH POWER ENERGY
- Filing Date
- 2026-04-08
- Publication Date
- 2026-06-05
Smart Images
Figure CN122158783A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery recycling technology, and in particular relates to a method for regenerating waste ternary cathode materials and the regenerated ternary cathode materials. Background Technology
[0002] With the increasing global demand for sustainable energy, lithium-ion batteries, due to their superior performance, are widely used in electrochemical energy storage and electric vehicles. Among them, ternary materials (NCM) have become the mainstream cathode material for power batteries due to their advantages such as high energy density, excellent cycle performance, and relatively good safety. In recent years, the new energy industry has developed rapidly, and it is expected that the application of ternary batteries in the electric vehicle field will further expand in the future. However, the limited battery life will lead to a large number of waste ternary lithium batteries in the future.
[0003] Discarded ternary lithium batteries contain valuable transition metals such as nickel, cobalt, and manganese, which have extremely high economic value for recycling. Improper handling will not only result in a serious waste of valuable metal resources and violate the strategic policy of sustainable development, but will also put enormous pressure on the ecological environment.
[0004] Currently, traditional methods for recycling waste cathode materials are mainly divided into pyrometallurgy and hydrometallurgy. However, both technologies have inherent drawbacks. Pyrometallurgical processes are typically extremely energy-intensive and easily introduce impurities during high-temperature processing, resulting in low product purity and associated waste gas emissions, making them environmentally unfriendly. While hydrometallurgy offers higher metal recovery rates, its complex process involves the use of large quantities of acid and alkali reagents, leading to high costs and the generation of waste liquid, causing secondary pollution.
[0005] To address the aforementioned issues, direct regeneration technology has emerged. This technology restores the electrochemical activity of failed cathode materials by replenishing elements and repairing their structure. Compared to traditional methods, direct regeneration technology offers significant advantages such as high recycling efficiency, simple processes, low cost, and environmental friendliness, and is considered one of the most promising cathode material recycling pathways. However, existing direct regeneration technologies still have limitations: the electrochemical performance of recycled materials obtained through this method is typically only restored to the level of the original material, but the performance standards of the original material are often outdated compared to the continuously evolving commercial cathode materials currently on the market; furthermore, some regeneration processes are quite demanding, limiting their large-scale application. Therefore, how to improve and modify the electrochemical performance of waste materials while simultaneously regenerating them, so that they can meet or even exceed current and future application standards, has become a pressing technical challenge in this field. Summary of the Invention
[0006] To address the aforementioned problems in the existing technology, this invention provides a method for regenerating waste ternary cathode materials and a method for regenerating ternary cathode materials, which enables efficient regeneration of waste batteries and yields regenerated ternary cathode materials with excellent electrochemical performance.
[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows: In a first aspect, this application provides a method for regenerating waste ternary cathode materials, including: Waste ternary cathode powder was calcined and purified to obtain purified ternary cathode powder. The purified ternary cathode powder was mixed with a lithium source, a titanium source and an alcohol solvent to obtain a mixed system. After the mixed system underwent a hydrothermal reaction, it was purified and dried to obtain modified ternary cathode powder. The modified ternary cathode powder is mixed with a lithium source and then annealed in an oxygen atmosphere to obtain a recycled ternary cathode material.
[0008] By introducing a lithium titanate (LTO) coating layer that combines zero-strain characteristics and fast ion conduction while repairing the crystal structure through hydrothermal lithium replenishment, the electrolyte erosion is physically isolated and side reactions are suppressed, while lithium-ion diffusion is accelerated kinetically, thereby improving the electrochemical performance of the battery and achieving efficient regeneration of ternary cathode materials.
[0009] Optionally, the hydrothermal reaction conditions are 130-200℃ for 6-16 hours.
[0010] Hydrothermal reactions within this temperature and time range can effectively promote the insertion of lithium ions into the ternary material lattice, while simultaneously achieving uniform coating of the titanium source on the material surface, forming a stable lithium titanate layer.
[0011] Optionally, the lithium source is one or more of lithium hydroxide, lithium nitrate, and lithium acetate; And / or, the mass ratio of purified ternary cathode powder to lithium source is 1:(0.2-1). And / or, the titanium source is one or more of tetrabutyl titanate, titanium tetrachloride, and isopropyl titanate, and the mass ratio of the titanium source to the purified ternary cathode powder is (0.1-0.3) mL / g; And / or, the alcohol solvent is ethylene glycol; 50-80 mL of ethylene glycol is added for each gram of purified ternary cathode powder.
[0012] By optimizing the type and ratio of lithium source, sufficient lithium replenishment was ensured during the hydrothermal process. The reasonable ratio of titanium source dosage to ethylene glycol volume is conducive to the formation of a uniform and dense lithium titanate coating layer, avoiding excessive titanium source leading to surface side reactions or an excessively thick coating layer affecting lithium ion transport, thus improving the rate performance and cycle stability of the recycled material.
[0013] Optionally, the mixture may also include water.
[0014] The introduction of an appropriate amount of water can promote the hydrolysis of the titanium source in order to form a lithium titanate coating.
[0015] Optionally, the waste ternary cathode powder is selected from one or more of the following waste ternary cathode powders: LiNi 0.3 Co 0.3 Mn 0.3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2.
[0016] By recycling various types of waste ternary cathode powders, good applicability to the recycling of ternary cathode materials with different nickel contents has been achieved.
[0017] Optionally, the calcination purification includes calcining in air at 400-600°C for 4-8 hours.
[0018] Calcination under these conditions can effectively remove residual conductive agents, binders, and carbon impurities from the surface of waste ternary cathode materials.
[0019] Optionally, the annealing conditions are: in an oxygen atmosphere, treated at 780-850°C for 4-8 hours.
[0020] High-temperature annealing in an oxygen atmosphere can further promote the uniform diffusion of lithium ions into the crystal lattice, while crystallizing the lithium titanate coating to form a stable surface structure, thereby improving the thermal stability and electrochemical cycle life of the material.
[0021] Optionally, the ratio of modified ternary cathode powder to lithium hydroxide is 1:(0.03-0.08).
[0022] By supplementing lithium twice, the potential lithium deficiency problem during the hydrothermal process can be compensated.
[0023] Optionally, the purification includes filtration and washing with ethanol; And / or, the drying includes drying at 60-90°C for 5-12 hours.
[0024] By purifying and drying, water and solvents are removed, ensuring the battery's high-efficiency transmission performance.
[0025] Secondly, this application also provides a recycled ternary cathode material, which is prepared by the recycling method described in the first aspect.
[0026] The regenerated ternary cathode material prepared by the above regeneration method achieves excellent rate performance and cycle stability.
[0027] Compared with the prior art, the present invention has at least the following beneficial effects: This invention improves the electrochemical performance of a battery by introducing a lithium titanate (LTO) coating layer that combines zero-strain characteristics with fast ion conduction while simultaneously repairing the crystal structure through hydrothermal lithium replenishment. This layer physically isolates the battery from electrolyte corrosion and suppresses side reactions, while kinetically accelerating lithium-ion diffusion. The recycled and upgraded material obtained by this invention exhibits a 0.1C discharge specific capacity as high as 182.99 mAh g⁻¹. -1 Surpassing commercially available fresh NCM materials; after 100 cycles at 1C, the capacity retention rate reaches 89.15%, and the reversible capacity at a high rate of 10C is still 90 mAh g. -1 Its overall electrochemical performance is significantly better than that of traditional recycled materials and commercially available products.
[0028] By simultaneously introducing a titanium source during hydrothermal regeneration and combining it with a short-time annealing treatment, lithium replenishment and lithium titanate coating can be completed in one step. This process is simple, avoids the cumbersome operations of traditional regeneration, significantly shortens the process flow, and produces regenerated ternary cathode materials with excellent performance.
[0029] The method described in this application is not only applicable to the recycling and upgrading of waste NCM622, but also to other types of NCM cathode materials such as waste NCM111. This technical approach can also be extended to the recycling of future ultra-high nickel cathode materials and other types of cathode materials, providing a new technical path for solving the problems of waste battery recycling and material performance improvement. Attached Figure Description
[0030] Figure 1 The XRD diffraction patterns of the recycled ternary cathode material, waste ternary cathode powder, and commercial NCM622 (C-NCM) powder obtained in Examples 1, 2, 3, and 4 are shown. Figure 2 SEM images of the waste ternary cathode powder, the purified ternary cathode powder, and C-NCM used in this invention; Figure 3 SEM images of the regenerated ternary cathode materials obtained in Examples 1, 2, 3, and 4; Figure 4 EDS elemental distribution diagram of the regenerated ternary cathode material R-NCM-5% LTO prepared in Example 3; Figure 5The first charge-discharge curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM, are shown at 0.1 C, 25 °C, and a voltage range of 2.7-4.3 V. Figure 6 The cycling performance test curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM, are shown below at 1 C, 25 °C, and a voltage range of 2.7-4.3 V. Figure 7 Rate performance test curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM at different charging rates, 25°C, and voltage ranges of 2.7-4.3 V; Figure 8 The AC impedance test curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM are shown. Figure 9 The graph shows the lithium-ion diffusion coefficients of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4 and the D-NCM sample in the early voltage range of 3-4.2 V. Figure 10 The dQ / dV curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and the D-NCM and C-NCM samples, are shown at 0.1 C charge and discharge. Detailed Implementation
[0031] The present invention will now be described in further detail with reference to the accompanying drawings: Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.
[0032] All reagents and materials used in this example can be purchased routinely. The quantitative experiments involved in the examples were all repeated at least three times, and the results were averaged.
[0033] Raw material source: Waste ternary cathode powder: obtained by dismantling waste NCM622 batteries and separating the cathode material from the aluminum foil.
[0034] Example 1
[0035] A method for regenerating waste ternary cathode materials, comprising the following steps: 1. Pour 50 g of the crushed waste ternary cathode powder (D-NCM) into a 300-mesh sieve to sieve the D-NCM and remove the larger aluminum impurities. Then weigh 5 g of the sieved powder and put it into an alumina magnetic boat. Place the boat into a muffle furnace and sinter at 400℃ for 4 hours to remove various impurities (such as binders) from the particle surface, and obtain purified ternary cathode powder (P-NCM).
[0036] 2. After the purified ternary cathode powder was placed in a vacuum oven and dried at 80°C for 12 hours, 1 g of the powder and 0.2388 g of lithium hydroxide were added to a reaction vessel containing 70 mL of ethylene glycol and stirred magnetically for 1 hour to obtain a mixed system.
[0037] 3. The above-obtained mixture was placed in a forced-air drying oven and hydrothermally reacted at 140°C for 8 hours. After the hydrothermal reaction was completed, the sample was filtered and washed three times with ethanol. Then, it was placed in a forced-air drying oven and dried at 80°C for 6 hours to obtain modified ternary cathode powder.
[0038] 4. Weigh 0.4 g of the above modified ternary cathode powder and 0.02 g of lithium hydroxide and put them into a mortar and mix them evenly. Then transfer them to an alumina magnetic boat and anneal them at 800°C for 4 hours in a tube furnace filled with oxygen. The heating rate is 10°C / min to obtain the regenerated ternary cathode material (R-NCM).
[0039] Example 2
[0040] A method for regenerating waste ternary cathode materials, comprising the following steps: 1. Pour 50 g of the crushed waste ternary cathode powder (D-NCM) into a 300-mesh sieve to sieve the D-NCM and remove the larger aluminum impurities. Then weigh 5 g of the sieved powder and put it into an alumina magnetic boat. Place the boat into a muffle furnace and sinter at 400 ℃ for 4 hours to remove various impurities on the particle surface and obtain purified ternary cathode powder (P-NCM).
[0041] 2. After the purified ternary cathode powder is placed in a vacuum oven and dried at 80°C for 12 hours, 1 g of the powder, 0.25 g of lithium hydroxide and 0.1123 mL of tetrabutyl titanate are added to the inner liner of a reactor containing 70 mL of ethylene glycol. The mixture is magnetically stirred for 1 hour. During the stirring process, deionized water of the same volume as tetrabutyl titanate is added dropwise to obtain a mixed system.
[0042] 3. The above-obtained mixture was placed in a forced-air drying oven and hydrothermally reacted at 140°C for 8 hours. After the hydrothermal reaction was completed, the sample was washed three times by ethanol filtration and then placed in a forced-air drying oven and dried at 80°C for 6 hours to obtain modified ternary cathode powder.
[0043] 4. Weigh 0.4 g of the above modified ternary cathode powder and 0.02 g of lithium hydroxide and put them into a mortar and mix them evenly. Transfer the mixture to an alumina magnetic boat and anneal it at 800°C for 4 hours in a tube furnace filled with oxygen. The heating rate is 10°C / min to obtain a 3wt% lithium titanate-coated regenerated ternary cathode material (R-NCM-3% LTO).
[0044] Example 3
[0045] A method for regenerating waste ternary cathode materials, comprising the following steps: 1. Pour 50 g of crushed waste ternary cathode powder (D-NCM) into a 300-mesh sieve to sieve the D-NCM and remove the larger aluminum impurities. Then weigh 5 g of the sieved powder and put it into an alumina magnetic boat. Place the boat into a muffle furnace and sinter at 400℃ for 4 hours to remove various impurities on the particle surface and obtain purified ternary cathode powder (P-NCM).
[0046] 2. After the purified ternary cathode powder was placed in a vacuum oven and dried at 80°C for 12 hours, 1 g of the powder, 0.2575 g of lithium hydroxide and 0.1871 mL of tetrabutyl titanate were added to a reaction vessel containing 70 mL of ethylene glycol. The mixture was magnetically stirred for 1 hour. During the stirring process, deionized water of the same volume as tetrabutyl titanate was added dropwise to obtain a uniform mixed system.
[0047] 3. Place the above-obtained mixture in a forced-air drying oven at 140°C for 8 hours for hydrothermal treatment. After hydrothermal treatment is complete, wash the sample three times with ethanol by filtration, and then place it in a forced-air drying oven at 80°C for 6 hours to obtain modified ternary cathode powder.
[0048] 4. Weigh 0.4 g of the above modified ternary cathode powder and 0.02 g of lithium hydroxide and put them into a mortar and mix them evenly. Transfer the mixture to an alumina magnetic boat and anneal it at 800°C for 4 hours in a tube furnace filled with oxygen at a heating rate of 10°C / min to obtain a 5wt% lithium titanate-coated regenerated ternary cathode material (R-NCM-5% LTO).
[0049] Example 4
[0050] A method for regenerating waste ternary cathode materials, comprising the following steps: 1. Pour 50 g of the crushed waste ternary cathode powder (D-NCM) into a 300-mesh sieve to sieve the D-NCM and remove the larger aluminum impurities. Then weigh 5 g of the sieved powder and put it into an alumina magnetic boat. Place the boat into a muffle furnace and sinter at 400 ℃ for 4 hours to remove various impurities on the particle surface and obtain purified ternary cathode powder (P-NCM).
[0051] 2. After the purified ternary cathode powder was placed in a vacuum oven and dried at 80°C for 12 hours, 1 g of the powder, 0.2650 g of lithium hydroxide and 0.2620 mL of tetrabutyl titanate were added to a reaction vessel containing 70 mL of ethylene glycol. The mixture was magnetically stirred for 1 hour. During the stirring process, deionized water of the same volume as tetrabutyl titanate was added dropwise to obtain a homogeneous mixture.
[0052] 3. Place the above-obtained mixture in a forced-air drying oven at 140°C for 8 hours for hydrothermal treatment. After hydrothermal treatment is complete, wash the sample three times with ethanol by filtration, and then place it in a forced-air drying oven at 80°C for 6 hours to obtain modified ternary cathode powder.
[0053] 4. Weigh 0.4 g of the above modified ternary cathode powder and 0.02 g of lithium hydroxide and put them into a mortar and mix them evenly. Transfer the mixture to an alumina magnetic boat and anneal it in a tube furnace filled with oxygen at 800°C for 4 hours with a heating rate of 10°C / min to obtain a 7wt% lithium titanate-coated regenerated ternary cathode material (R-NCM-7% LTO).
[0054] The test results are as follows: Figure 1 The XRD diffraction patterns of the regenerated ternary cathode material, waste ternary cathode powder, and commercial NCM622 (C-NCM) powder obtained in Examples 1, 2, 3, and 4 are shown (PDF #74-0919 is the standard PDF card for ternary cathode materials). It can be seen that the diffraction peak shape of the regenerated ternary cathode material prepared using the method of this invention is consistent with that of commercial NCM, with no impurity phases present and excellent crystallinity.
[0055] Figure 2 The images show SEM images of the waste ternary cathode powder, the purified ternary cathode powder, and C-NCM in Example 1 of this invention. The images show that the purified ternary cathode powder has a cleaner, smoother surface and is free of impurities compared to the waste NCM.
[0056] Figure 3 The images show SEM images of the ternary cathode materials obtained from the regeneration and upgrading processes in Examples 1, 2, 3, and 4. The regenerated ternary cathode materials prepared using the method of this invention have clean particle surfaces, with no particle agglomerates observed, and their size and morphology are consistent with those of commercial NCM materials.
[0057] Figure 4 The image shows the EDS elemental distribution of the R-NCM-5% LTO sample prepared in Example 3. The uniform distribution of titanium indicates that lithium titanate is uniformly coated on the surface of the NCM material.
[0058] Figure 5The first charge-discharge curves of the ternary cathode materials obtained from the regeneration and upgrading in Examples 1, 2, 3, and 4, and D-NCM and C-NCM, are shown at 0.1 C and 25 °C. Compared with R-NCM and C-NCM, R-NCM-LTO (Examples 2-4) exhibits a higher discharge capacity, with a maximum discharge specific capacity of 182.99 mAh g⁻¹. -1 The R-NCM and C-NCM materials have a combined energy content of only 163.06 mAh g. -1 and 173.51 mAh g -1 .
[0059] Figure 6 The cycling performance curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM, are shown at 1C, 25 °C, and a voltage range of 2.7–4.3 V. The R-NCM-5% LTO sample exhibits the highest capacity retention, with a capacity retention of 89.15% after 100 cycles at 1C. The capacity retention of R-NCM and C-NCM materials is 86.86% and 86.09%, respectively. This demonstrates that LTO coating can improve the structural stability of the cathode material, and R-NCM-5% LTO exhibits excellent cycling stability.
[0060] Figure 7 Rate performance curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM, are shown at different charging rates, 25 °C, and voltage ranges of 2.7–4.3 V. Under a high current density of 10 C, R-NCM-5% LTO exhibits a high efficiency of up to 90 mAh g⁻¹. -1 The reversible capacity of C-NCM is 87.17 mAh g. -1 This confirms that R-NCM-5%LTO has good rate performance.
[0061] Figure 8 The figures show the AC impedance test curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and D-NCM and C-NCM. It can be seen from the figures that the impedance of the R-NCM-LTO sample is lower than that of the other samples, proving that appropriate LTO coating modification can improve the material interface structure and thus reduce internal resistance.
[0062] Figure 9 The graphs show the lithium-ion diffusion coefficients of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and the D-NCM sample, within a voltage range of 3-4.2 V. The lithium-ion diffusion coefficients of the R-NCM-LTO sample are all higher than those of the uncoated LTO sample, confirming that LTO, as a fast ion conductor, can effectively improve lithium-ion diffusion kinetics and enhance battery performance.
[0063] Figure 10The figures show the dQ / dV curves of the regenerated ternary cathode materials prepared in Examples 1, 2, 3, and 4, and the D-NCM and C-NCM samples, under 0.1 C charge-discharge conditions. The figures show that the redox peak of D-NCMD shifts outwards, but the curves of R-NCM and R-NCM-5% LTO are basically consistent with those of C-NCM, indicating that the crystal structure of the regenerated materials has been restored.
Claims
1. A method for regenerating waste ternary cathode materials, characterized in that, include: Waste ternary cathode powder was calcined and purified to obtain purified ternary cathode powder. The purified ternary cathode powder was mixed with a lithium source, a titanium source and an alcohol solvent to obtain a mixed system. After the mixed system underwent a hydrothermal reaction, it was purified and dried to obtain modified ternary cathode powder. The modified ternary cathode powder is mixed with a lithium source and then annealed in an oxygen atmosphere to obtain a recycled ternary cathode material.
2. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The hydrothermal reaction conditions are 130-200℃ for 6-16 hours.
3. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The lithium source is one or more of lithium hydroxide, lithium nitrate, and lithium acetate; And / or, the mass ratio of purified ternary cathode powder to lithium source is 1:(0.2-1). And / or, the titanium source is one or more of tetrabutyl titanate, titanium tetrachloride, and isopropyl titanate, and the ratio of the titanium source to the purified ternary cathode powder is (0.1-0.3):1 mL / g; And / or, the alcohol solvent is ethanol.
4. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The mixture also includes water.
5. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The waste ternary cathode powder is selected from one or more of the following waste ternary cathode powders: LiNi 0.3 Co 0.3 Mr 0.3 O2、LiNi 0.5 Co 0.2 Mr 0.3 O2、LiNi 0.6 Co 0.2 Mr 0.2 O2、LiNi 0.8 Co 0.1 Mr 0.1 O2。 6. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The calcination purification includes calcining in air at 400-600°C for 4-8 hours.
7. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The annealing conditions are as follows: in an oxygen atmosphere, at 780-850℃ for 4-8 hours.
8. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The mass ratio of modified ternary cathode powder to lithium hydroxide is 1:(0.03-0.08).
9. The method for regenerating waste ternary cathode materials according to claim 1, characterized in that, The purification process includes filtration followed by washing with ethanol; And / or, the drying includes drying at 60-90°C for 5-12 hours.
10. A recycled ternary cathode material, characterized in that, It is prepared by the regeneration method according to any one of claims 1-9.