Cascade microwave self-repairing treatment method for new energy ternary lithium old battery material
By combining microwave heating technology with a cascade process, the problems of complex processes, high energy consumption, and environmental pollution in the recycling of ternary lithium-ion batteries have been solved, achieving efficient material repair and performance restoration, and improving the electrochemical performance of the materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-16
- Publication Date
- 2026-04-10
AI Technical Summary
Existing ternary lithium-ion battery recycling technologies suffer from problems such as complex processes, high energy consumption, serious environmental pollution, and unsatisfactory recovery of the electrochemical performance of materials after repair.
By combining microwave heating technology with a specific stepped process, lithium source melting and penetration and crystal structure repair are carried out through a two-stage microwave roasting process, including low-temperature microwave melting roasting and high-temperature microwave self-healing roasting, so as to achieve uniform replenishment of lithium elements and lattice recombination.
It achieves efficient and energy-saving material repair, restores the electrochemical properties of materials, reduces energy consumption and environmental pollution, and improves the reversible specific capacity and cycle stability of materials.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of lithium ion battery recycling, in particular to a new energy ternary lithium old battery material gradient microwave self-repairing treatment method. BACKGROUND
[0002] With the rapid development of new energy vehicle industry, a large number of ternary lithium ion batteries enter the retirement period. Ternary cathode materials are widely used due to their high energy density, but they have high production energy consumption and high cost, and contain strategic metal resources such as nickel and cobalt, so their recycling and utilization have great economic and environmental value.
[0003] Traditional recycling methods mainly include pyrometallurgy and hydrometallurgy. Pyrometallurgy has huge energy consumption and is easy to cause lithium element loss; the hydrometallurgical process is long and needs to use strong acid and strong base, which produces a large amount of wastewater and slag, and has the risk of secondary pollution. In recent years, direct regeneration and repair technology has attracted attention due to its short process, low cost and environmental friendliness. However, the existing direct regeneration technology mainly uses conventional electric heating roasting, which has problems such as uneven heating, long repair time, high energy consumption, and incomplete repair of key lithium-nickel mixed defects in the crystal structure, resulting in unsatisfactory recovery of the electrochemical performance of the regenerated material. Therefore, it is urgent to develop a new technology for efficient direct regeneration of ternary cathode materials. SUMMARY
[0004] The present application aims to overcome the deficiencies in the prior art, such as complex process, high energy consumption, serious secondary pollution, and unsatisfactory recovery of the electrochemical performance of the material after repair, and to provide an efficient, energy-saving and environmentally friendly gradient microwave self-repairing treatment technology for ternary lithium old battery materials. This method innovatively combines microwave bulk heating technology with a specific gradient process. First, ternary cathode materials are separated from the complex waste battery mixed electrode powder through efficient physical separation technology. Then, a two-stage microwave repair path is designed to address key issues such as lithium loss, crystal structure defects and surface degradation during the cycle decay process. This path uses a precisely controlled gradient temperature field to achieve lithium source melting penetration at medium-low temperature microwave conditions, and then drives deep repair and reorganization of the crystal structure at high temperature microwave conditions, thereby achieving material repair at the atomic / lattice level. This provides a new solution for the resource recycling of waste lithium ion batteries.
[0005] A new energy ternary lithium old battery material gradient microwave self-repairing treatment method, comprising the following steps:
[0006] Step 1: Selecting waste ternary lithium battery powder, achieving efficient component separation of mixed electrode powder through "flotation-reselection" combined process, and obtaining ternary lithium cathode powder;
[0007] Step 2: Supplementing lithium source to obtain a mixture;
[0008] Step 3: The mixed material after supplementing the lithium source is subjected to structure repair by adopting a two-stage microwave roasting process, i.e., low-temperature microwave melting roasting treatment and high-temperature microwave self-repairing roasting treatment, to obtain the material after high-temperature microwave repair;
[0009] Step 4: The material after high-temperature microwave repair is cooled to room temperature under air or inert atmosphere, and then washed by deionized water and dried to obtain the regenerated ternary lithium positive electrode material.
[0010] Further, the flotation process of step 1 adopts a closed circuit process of "one roughing, two cleaning and one scavenging", and uses an alkyl collector and a foaming agent; the gravity separation process separates copper and aluminum enrichment materials from the flotation tailings according to the density difference of the materials, and obtains a high-purity ternary lithium positive electrode powder.
[0011] Further, the lithium source supplementing in step 2 is that the lithium content of the ternary lithium positive electrode powder is determined by component analysis, and lithium hydroxide is supplemented according to the stoichiometric ratio, so that the molar ratio of total Li to transition metal in the mixed material is 1.05-1.35.
[0012] Further, the low-temperature microwave melting roasting treatment in step 3 is that the mixed material is placed in a microwave roasting device and heated by microwave under air or oxygen-containing atmosphere; the target temperature of microwave heating is controlled at 470-570 DEG C, and the holding time is 20-40 min.
[0013] Further, the high-temperature microwave self-repairing roasting treatment in step 3 is that the mixed material in the microwave roasting device is heated to a higher temperature range of 750-800 DEG C under air atmosphere, and the holding time is 60-120 min.
[0014] Further, the regenerated ternary lithium positive electrode material in step 4 has a first discharge specific capacity of more than 140 mAh / g at 0.1C rate after installation, and a capacity retention rate of more than 85.5% after 500 cycles.
[0015] Further, the dosage of the alkyl collector is 400-600 g / t, and the dosage of the foaming agent is 150-200 g / t.
[0016] Compared with the prior art, the beneficial effects of the present application are that:
[0017] 1. The "low-temperature melt infiltration + high-temperature lattice repair" step-by-step microwave repair technology realizes effective lattice repair. In the low-temperature stage, LiOH is used for melt to realize uniform pre-diffusion and surface purification of lithium source; in the high-temperature stage, energy is concentrated to complete lattice repair and structure rearrangement, with clear division of labor, high repair efficiency and thoroughness.
[0018] 2. The microwave heating has obvious advantages: microwave body heating has fast heating speed and high thermal efficiency, and the energy consumption is significantly lower than that of traditional resistance furnaces. The selective heating and internal heating characteristics of microwaves make the material heated very uniformly, avoiding the problem of large temperature gradient and uneven repair caused by traditional external heating.
[0019] 3. The regenerated material has excellent performance: the method can effectively reverse Li / Ni mixing and restore the layered structure of the material. The regenerated ternary material has high reversible specific capacity, excellent cycle stability and rate performance.
[0020] 4. Environmentally friendly: no strong acid or strong base is needed in the whole process, avoiding the generation of a large amount of waste liquid, and the microwave treatment time is short, with low carbon emission, which is a green recycling technology. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The process flow chart of the ternary lithium old battery material step-by-step microwave self-repairing treatment technology is shown. DETAILED DESCRIPTION
[0022] The application will be further described in conjunction with the examples, but the protection scope of the application is not limited to the examples.
[0023] A new energy ternary lithium old battery material step-by-step microwave self-repairing treatment method, as shown in Figure 1 includes the following steps:
[0024] Step 1: Selecting waste ternary lithium battery powder, realizing efficient component separation of mixed electrode powder through "flotation-gravity separation" combined process, and obtaining ternary lithium positive electrode powder; wherein, the flotation process adopts "one roughing, two cleaning and one scavenging" closed circuit process, uses alkyl collector and foaming agent, and separates graphite negative electrode concentrate based on the difference in surface hydrophobicity; the gravity separation process further separates copper and aluminum concentrates from the flotation tailings by using the difference in material density, and obtains high-purity ternary lithium positive electrode powder as raw material for subsequent step-by-step microwave repair.
[0025] Step 2: Supplementing lithium source, analyzing the composition of the ternary lithium positive electrode powder, and determining the lithium content; according to the stoichiometric ratio, supplementing lithium hydroxide compound to make the molar ratio of total Li to transition metal in the mixture 1.05-1.35, and obtaining the mixture;
[0026] Step 3: Step-by-step microwave self-repairing roasting treatment, which is the core repair stage, uses two-stage microwave roasting process to repair the structure of the mixed material after supplementing the lithium source. The two-stage microwave roasting process is to first perform low-temperature microwave melting roasting treatment on the mixed material, and then perform high-temperature microwave self-repairing roasting treatment to obtain the material after high-temperature microwave repair;
[0027] (1) Low-temperature microwave melting roasting treatment
[0028] The mixed material is placed in a microwave roasting device and heated in an air or oxygen-containing atmosphere using microwaves. The target temperature of microwave heating is controlled at 470-570°C, and the holding time is 20-40 min. The purpose of this stage is to use the rapid bulk heating characteristics of microwaves to melt the added lithium hydroxide (melting point 462°C), so that the molten lithium source can fully penetrate and infiltrate into the surface and micro-cracks of the waste NCM particles, creating favorable conditions for lithium diffusion. At the same time, this temperature range can effectively remove impurities such as conductive carbon and organic binders on the surface of the material.
[0029] (2) High-temperature microwave self-repairing roasting treatment
[0030] The material is further heated in a microwave field to a higher temperature range of 750-800°C in an air atmosphere and held for 60-120 min. The purpose of this high-temperature stage is to provide enough energy to drive lithium ions to diffuse into the NCM crystal lattice, embed into the lithium-deficient lattice sites, and achieve an efficient "re-lithiation" process. At the same time, the high-temperature thermodynamic conditions can drive the rearrangement of lattice atoms, effectively reverse the lithium-nickel cation mixing defects caused by cycling, restore the crystal structure from disordered rock salt or spinel phase to regular layered structure, and promote the regrowth of crystal grains.
[0031] Step 4: The material after high-temperature microwave repair is cooled to room temperature in an air or inert atmosphere, and then washed with deionized water to remove residual soluble lithium salts on the surface. Finally, the washed material is dried to obtain a regenerated ternary lithium cathode material. The regenerated ternary lithium cathode material has a first discharge specific capacity of more than 140 mAh / g at 0.1C rate and a capacity retention rate of more than 85.5% after 500 cycles.
[0032] Example 1
[0033] A new energy ternary lithium old battery material step-by-step microwave self-repairing treatment method, comprising the following steps:
[0034] Step 1: Take the waste ternary lithium battery powder provided by a new energy company in Tianjin, the dosage of alkyl collector is 450 g / t, the dosage of foaming agent is 180 g / t, after flotation-gravity separation, the obtained ternary lithium positive electrode powder, the Li / TM (transition metal) molar ratio is 0.92.
[0035] Step 2: Supplement lithium source: according to the stoichiometry, supplement lithium hydroxide to make the total Li / TM molar ratio reach 1.20; adopt dry mechanical mixing method to mix uniformly to obtain a mixture;
[0036] Step 3: Gradient microwave self-repairing roasting treatment: place the mixed uniform material in the microwave roasting furnace, first perform low-temperature microwave melting roasting treatment: under air atmosphere, start microwave heating, heat the material to 520℃, and keep the temperature for 30 minutes; then perform high-temperature microwave self-repairing roasting treatment: continue to heat, under air atmosphere, heat the material to 770℃, and microwave heat for 90 minutes at this temperature.
[0037] Step 4: Cooling and water washing and drying: after the program is completed, the material is cooled to room temperature with the furnace, washed twice with deionized water, and dried to obtain the regenerated NCM (nickel-cobalt-manganese ternary) material. The first discharge specific capacity of the obtained regenerated material is 142.5 mAh / g at 0.1C rate, and the capacity retention rate is 88.5% after 500 cycles.
[0038] Example 2
[0039] A new energy ternary lithium old battery material gradient microwave self-repairing treatment method, comprising the following steps:
[0040] Step 1: Take the waste ternary lithium battery powder provided by a new energy company in Shenzhen, the dosage of alkyl collector is 600 g / t, the dosage of foaming agent is 200 g / t, after flotation-gravity separation, the obtained ternary lithium positive electrode powder, the Li / TM (transition metal) molar ratio is 0.98.
[0041] Step 2: Supplement lithium source: according to the stoichiometry, supplement lithium hydroxide to make the total Li / TM molar ratio reach 1.32, mix uniformly to obtain a mixture;
[0042] Step 3: Gradient microwave self-repairing roasting treatment: place the mixed uniform material in the microwave roasting furnace, first perform low-temperature microwave melting roasting treatment: under air atmosphere, start microwave heating, heat the material to 570℃, and keep the temperature for 40 minutes; then perform high-temperature microwave self-repairing roasting treatment: continue to heat, under air atmosphere, heat the material to 790℃, and microwave heat for 120 minutes at this temperature.
[0043] Step 4: cooling and water washing and drying: after the end of the procedure, the material is cooled to room temperature with the furnace, washed twice with stirring using deionized water, and dried to obtain the regenerated NCM material. The obtained regenerated material is loaded into a battery, and the first discharge specific capacity at 0.1C rate is 149.6 mAh / g, and the capacity retention rate after 500 cycles is 89.5%.
[0044] Example 3
[0045] A new energy ternary lithium old battery material step microwave self-repairing treatment method, comprising the following steps:
[0046] Step 1: take the waste ternary lithium battery powder provided by a new energy company in Shaanxi, the dosage of alkyl collector is 400 g / t, the dosage of foaming agent is 150 g / t, after flotation-gravity separation, the obtained ternary lithium positive electrode powder is obtained, and the Li / TM (transition metal) molar ratio is 0.84.
[0047] Step 2: supplement lithium source: according to the stoichiometry, supplement lithium hydroxide to make the total Li / TM molar ratio reach 1.05, mix uniformly to obtain a mixture;
[0048] Step 3: step microwave self-repairing roasting treatment: place the mixed uniform material in the microwave roasting furnace, first perform low-temperature microwave melting roasting treatment: start microwave heating under air atmosphere, heat the material to 490℃, and keep the temperature for 25 minutes; then perform high-temperature microwave self-repairing roasting treatment: continue to heat the material to 750℃, and microwave heat at this temperature for 100 minutes.
[0049] Step 4: cooling and water washing and drying: after the end of the procedure, the material is cooled to room temperature with the furnace, washed twice with stirring using deionized water, and dried to obtain the regenerated NCM material. The obtained regenerated material is loaded into a battery, and the first discharge specific capacity at 0.1C rate is 149.6 mAh / g, and the capacity retention rate after 500 cycles is 89.5%.
[0050] Comparative example 4
[0051] The same as example 3, the same operation steps, the difference is that the conventional static roasting means is adopted for roasting: the positive electrode powder is placed in a muffle furnace under air atmosphere, heated to 500℃ for 40 minutes, and then heated to 800℃ for 120 minutes. The obtained material is detected, and the first discharge specific capacity is 115.4 mAh / g, the capacity retention rate after 600 cycles is 72.9%, and there is sintering phenomenon between particles, and the battery performance is lower than that of example. This comparative example shows that the traditional resistance furnace heating method, even if the roasting time is prolonged, due to the inherent defects of the heating method, the repair effect of microwave roasting cannot be achieved.
Claims
1. A method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy applications, characterized in that, Includes the following steps: Step 1: Select waste ternary lithium battery powder and use a combined "flotation-gravity separation" process to achieve efficient component separation of the mixed electrode powder to obtain ternary lithium cathode powder; Step 2: Add lithium source to obtain mixture; Step 3: The mixture after replenishing the lithium source is structurally repaired using a two-stage microwave roasting process. The two-stage microwave roasting process involves first subjecting the mixture to low-temperature microwave melting roasting, and then subjecting it to high-temperature microwave self-repair roasting, to obtain a material that has completed high-temperature microwave repair. Step 4: Cool the material that has undergone high-temperature microwave repair to room temperature in air or an inert atmosphere, then wash and dry the cooled material with deionized water to obtain the recycled ternary lithium cathode material.
2. The method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy sources according to claim 1, characterized in that, The flotation process in step 1 adopts a closed-loop process of "one roughing, two cleaning, and one scavenging", using alkyl collectors and frothers; the gravity separation process utilizes the density difference of materials to separate copper and aluminum concentrates from the flotation tailings and obtain high-purity ternary lithium cathode powder.
3. The method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy sources according to claim 1, characterized in that, The supplementary lithium source mentioned in step 2 is: to perform component analysis on the ternary lithium cathode powder, determine its lithium content, and supplement the lithium source compound lithium hydroxide according to the stoichiometric ratio, so that the total molar ratio of Li to transition metal in the mixture is 1.05~1.
35.
4. The method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy sources according to claim 1, characterized in that, The low-temperature microwave melting and calcining treatment described in step 3 is as follows: the mixture is placed in a microwave calcining device and heated by microwaves in air or an oxygen-containing atmosphere; the target temperature for microwave heating is controlled at 470℃~570℃, and the holding time is 20min~40min.
5. The method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy sources according to claim 1, characterized in that, The high-temperature microwave self-healing calcination treatment described in step 3 is as follows: continue to heat up in the microwave calcination device, and heat the mixture in the microwave calcination device to a higher temperature range of 750℃~800℃ in an air atmosphere, and keep it at that temperature for 60min~120min.
6. The method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy sources according to claim 1, characterized in that, After the recycled ternary lithium cathode material described in step 4 is installed, the initial discharge specific capacity at a rate of 0.1C is higher than 140mAh / g, and the capacity retention rate exceeds 85.5% after 500 cycles.
7. A method for cascaded microwave self-repair treatment of used ternary lithium battery materials for new energy sources according to claim 2, characterized in that, The dosage of the alkyl collector is 400g / t to 600g / t, and the dosage of the foaming agent is 150g / t to 200g / t.