Regeneration method for repairing waste lithium iron phosphate positive electrode material based on oxidation-reduction one-pot method
By using a one-pot oxidation-reduction method to repair waste lithium iron phosphate cathode materials, the problems of high energy consumption and pollution have been solved, realizing a green and efficient regeneration method and obtaining high-performance regenerated lithium iron phosphate materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUAZHONG UNIV OF SCI & TECH
- Filing Date
- 2024-11-21
- Publication Date
- 2026-05-22
Smart Images
Figure CN122073282A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium iron phosphate cathode material technology, and in particular to a regeneration method for repairing waste lithium iron phosphate cathode materials based on a one-pot redox process. Background Technology
[0002] Over the past decade, the demand for large-scale energy storage devices has increased significantly across various sectors. Among various alternative energy sources, lithium-ion rechargeable batteries are the most attractive power system, capable of operating at higher voltages and achieving higher energy density. Lithium iron phosphate (LiFePO4) batteries with an olivine structure, widely used in commercial hybrid vehicles, are recognized as a promising cathode material for lithium-ion batteries due to their high power, low cost, non-toxicity, good thermal safety, and high reversibility. Consequently, they are widely adopted, leading to the rapid generation of millions of tons of waste lithium batteries after their lifespan (3 to 10 years). Effective recycling and remanufacturing of waste lithium batteries helps recover valuable materials, reduces energy consumption from natural resource extraction, mitigates environmental pollution caused by end-of-life battery management, and makes lithium batteries cheaper and more sustainable.
[0003] Currently, there are many methods for recycling waste lithium iron phosphate (LFP) cathode materials, including pyrometallurgical methods, hydrometallurgical methods, high-temperature solid-state remediation methods, and direct regeneration methods. Pyrometallurgical recycling of waste LFP cathode materials generally utilizes high-temperature technology to extract valuable metals from the material. The process is simple and widely applicable, but it generates very high energy consumption and produces toxic gases that pollute the environment. Hydrometallurgical methods are currently the most widely used method for recycling LFP materials. This method mainly involves dissolving the waste LFP with acids and alkalis, and then using various separation methods to extract the elements. Because hydrometallurgical methods can recycle large quantities of waste batteries, they are widely used in industry. However, hydrometallurgical methods generate large amounts of wastewater and waste residue, making it difficult to achieve the goal of green, environmentally friendly, and low-value recycling of LFP. More importantly, hydrometallurgical methods cannot recover 100% of all elements. To further improve the efficiency of LFP recycling, researchers have begun to study methods for directly repairing the LFP crystal lattice.
[0004] In view of this, it is necessary to design an improved regeneration method based on the one-pot redox process to repair waste lithium iron phosphate cathode materials in order to solve the above problems. Summary of the Invention
[0005] To address the shortcomings of the existing technology, the present invention aims to provide a regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process. Unlike traditional lithium iron phosphate recycling or other regeneration methods, this method simplifies the recycling and regeneration process steps and procedures. Regenerated lithium iron phosphate cathode materials are obtained through in-situ lithium replenishment in a one-pot process, and the electrochemical performance of the regenerated lithium iron phosphate cathode materials is improved by nitrogen doping. The assembled battery achieves electrochemical performance that meets commercial battery standards.
[0006] To achieve the above objectives, this invention provides a regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process, comprising the following steps:
[0007] S1. After dismantling the waste lithium iron phosphate batteries, separate the lithium iron phosphate positive electrode sheet and the negative electrode graphite sheet, and use the lithium iron phosphate positive electrode sheet as the material to be processed.
[0008] S2. After calcining the material to be treated described in step S1 at 300-500°C for 1-2 hours in an inert gas protective atmosphere, the lithium iron phosphate powder is separated from the electrode by oscillation to obtain black powder of positive electrode active material. The black powder is calcined at 500-700°C for 2-3 hours in an oxygen atmosphere to obtain red powder to be treated.
[0009] S3. The red powder to be treated obtained in step S2 is ball-milled and mixed evenly with organic liquid medium, phosphate, lithium compound and organic reducing agent at room temperature, and then dried to obtain the mixture to be treated;
[0010] S4. The mixture to be treated obtained in step S3 is subjected to solid-phase reduction calcination in an inert gas protective atmosphere to obtain regenerated lithium iron phosphate cathode material.
[0011] As a further improvement of the present invention, in step S2, the inert gas is argon or nitrogen.
[0012] As a further improvement of the present invention, in step S3, the organic liquid medium is one of acetone, butanone, cyclohexanone, methyl ethyl ketone, ethanol, isopropanol, tert-butanol, diethyl ether, methyl propyl ether, tetrahydrofuran, 1,3-dioxolane, ethyl acetate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and polycarbonate.
[0013] Furthermore, the solid-liquid ratio of the red powder to be treated to the organic liquid medium is 5g:(30-35ml).
[0014] As a further improvement of the present invention, the phosphate is one of lithium dihydrogen phosphate, lithium monohydrogen phosphate, and ammonium dihydrogen phosphate.
[0015] The lithium compound is one of lithium hydroxide, lithium carbonate, lithium phosphate, and lithium oxide.
[0016] The organic reducing agent is one of sucrose, fructose, glucose, β-lactose and maltose, and the amount of the organic reducing agent is 20-25% of the mass of lithium iron phosphate in the material to be treated.
[0017] As a further improvement of the present invention, the ball milling time is 6 to 24 hours and the rotation speed is 400 to 450 r / min.
[0018] The molar ratio of Li, Fe, and P in the lithium compound, the red powder to be treated, and the phosphate is (1–1.1):1:(0.95–1.05).
[0019] As a further improvement of the present invention, in step S4, the inert gas is argon or nitrogen, the solid-phase reduction calcination temperature is 500-800°C, and the calcination time is 3-5 hours.
[0020] The beneficial effects of this invention are:
[0021] This invention provides a method for remediating waste lithium iron phosphate (LFP) cathode materials using a one-pot redox process. The method involves disassembling waste LFP batteries, separating the LFP cathode sheet and the negative electrode graphite sheet, and using the LFP cathode sheet as the material to be treated. The material to be treated is calcined in an inert gas atmosphere, and then LFP powder is separated from the electrode sheet by vibration to obtain a black powder of positive electrode active material. This black powder is calcined in an oxygen atmosphere to obtain a red powder to be treated. The red powder to be treated is then ball-milled and mixed uniformly with an organic liquid medium, phosphate, lithium compound, and organic reducing agent at room temperature, and dried to obtain a mixture to be treated. This mixture is then subjected to solid-phase reduction calcination in an inert gas atmosphere to obtain regenerated LFP powder material. This invention reduces element loss compared to other element extraction methods and reduces impurities that may be introduced by other recycling methods. It can be applied to treat waste LFP cathode materials with different failure levels and from different sources.
[0022] The present invention provides a method for regenerating waste lithium iron phosphate cathode materials based on a one-pot redox process. This method includes the selection of organic reducing agents and organic media. Choosing organic solvents such as acetone as liquid media helps to mix the waste lithium iron phosphate cathode powder with other raw materials more uniformly during high-energy ball milling, thereby aiding in the repair of the lithium iron phosphate lattice. It also includes the selection of raw materials for supplementing elements; choosing raw materials such as lithium dihydrogen phosphate can supplement the missing elements in the waste lithium iron phosphate material without producing environmentally polluting byproducts, making it green and environmentally friendly. Furthermore, it includes the selection of ball milling process parameters. Setting the process parameters results in a finer particle size in the mixture, thereby improving the performance of the regenerated lithium iron phosphate material obtained after high-temperature solid-phase reduction calcination.
[0023] The regeneration method of this invention reduces energy consumption, generates no wastewater or waste residue, and reduces exhaust gas emissions, which is of great significance for environmental protection. The raw materials used are simple, readily available, and low in cost, achieving the goal of low-value recycling of waste lithium iron phosphate materials, and has industrial production significance. Attached Figure Description
[0024] Figure 1 The flowchart illustrates the regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process provided by this invention.
[0025] Figure 2 The images show SEM images of the regenerated lithium iron phosphate cathode material and the waste lithium iron phosphate cathode material obtained in Example 1 of this invention.
[0026] Figure 3 These are TEM images of the regenerated lithium iron phosphate cathode material and the waste lithium iron phosphate cathode material obtained in Example 1 of the present invention.
[0027] Figure 4 The graphs show the charge-discharge cycle performance and rate performance of coin cells assembled from recycled lithium iron phosphate cathode material, waste lithium iron phosphate cathode material, and commercial lithium iron phosphate cathode material obtained in Example 1 of this invention.
[0028] Figure 5 The image shows the EIS spectrum of a coin cell assembled from the recycled lithium iron phosphate cathode material and the waste lithium iron phosphate cathode material obtained in Example 1 of this invention.
[0029] Figure 6 The graphs show the charge-discharge cycle performance and rate performance of coin cells assembled from the recycled lithium iron phosphate cathode materials obtained in Example 1 and Comparative Examples 2-3 of this invention. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0031] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.
[0032] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0033] This invention provides a regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process, such as... Figure 1 As shown, it includes the following steps:
[0034] S1. After dismantling the waste lithium iron phosphate batteries, separate the lithium iron phosphate positive electrode sheet and the negative electrode graphite sheet, and use the lithium iron phosphate positive electrode sheet as the material to be processed.
[0035] Specifically, the positive electrode sheet and the negative electrode graphite sheet of lithium iron phosphate can be separated by manual or mechanical methods.
[0036] S2. After calcining the material to be treated in step S1 at 300-500℃ for 1-2 hours in an inert gas protective atmosphere, the lithium iron phosphate powder is separated from the electrode by oscillation to obtain black powder of positive electrode active material. The black powder is then calcined at 500-700℃ for 2-3 hours in an oxygen atmosphere to obtain red powder to be treated.
[0037] Specifically, the lithium iron phosphate cathode material to be treated is calcined at 300–500°C for 1–2 hours under an argon or nitrogen protective atmosphere to deactivate and carbonize the organic matter or binder in the active material. Then, the lithium iron phosphate powder is separated from the cathode by means of vibration, and the lithium iron phosphate powder is ground manually or mechanically. The lithium iron phosphate powder is then sieved through a 100–400 mesh sieve to obtain a black powder of the cathode active material. The black powder is then calcined at 500–700°C for 2–3 hours in an oxygen atmosphere to remove conductive carbon and impurities such as PVDF (polyvinylidene fluoride), and to transform the crystal structure to obtain the red powder to be treated.
[0038] S3. The red powder to be treated obtained in step S2 is ball-milled and mixed evenly with organic liquid medium, phosphate, lithium compound and organic reducing agent at room temperature, and then dried to obtain the mixture to be treated.
[0039] Specifically, the red powder to be treated is dissolved in an organic liquid medium at a solid-liquid ratio of 5 g:(30-35 ml), and lithium compounds and phosphates are added to the solution according to a Li:Fe:P molar ratio of (1-1.1):1:(0.95-1.05). Then, 20%-25% organic reducing agent is added to the mixture. The mixture is ball-milled for 6-24 hours at a speed of 400-450 r / min and dried to obtain the mixture to be treated.
[0040] The organic liquid medium is one of acetone, butanone, cyclohexanone, methyl ethyl ketone, ethanol, isopropanol, tert-butanol, diethyl ether, methyl propyl ether, tetrahydrofuran, 1,3-dioxolane, ethyl acetate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and polycarbonate. The organic liquid medium helps to improve the dispersibility of the material.
[0041] The phosphate is one of lithium dihydrogen phosphate, lithium monohydrogen phosphate, and ammonium dihydrogen phosphate. The lithium compound is one of lithium hydroxide, lithium carbonate, lithium phosphate, and lithium oxide. The organic reducing agent is one of sucrose, fructose, glucose, β-lactose, and maltose, and the amount of organic reducing agent used is 20-25% of the mass of lithium iron phosphate in the material to be treated.
[0042] S4. The mixture to be treated obtained in step S3 is subjected to solid-phase reduction calcination in an inert gas protective atmosphere to obtain regenerated lithium iron phosphate cathode material.
[0043] Specifically, the mixture to be treated is placed in a tube furnace and subjected to solid-phase reduction calcination in an argon or nitrogen protective atmosphere at a temperature of 500–800℃ for 3–5 hours, ultimately yielding regenerated lithium iron phosphate cathode material. Solid-phase reduction calcination in an inert gas atmosphere not only repairs the crystal structure of lithium iron phosphate but also generates a carbon coating layer through the decomposition of organic reducing agents, further optimizing the material's electrochemical performance.
[0044] The following describes the regeneration method for repairing waste lithium iron phosphate cathode materials based on the one-pot oxidation-reduction method provided by the present invention, with reference to specific embodiments.
[0045] Example 1
[0046] Example 1 provides a regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process, comprising the following steps:
[0047] S1. After dismantling the waste lithium iron phosphate batteries, the positive electrode sheet and the negative electrode graphite sheet of lithium iron phosphate are separated by mechanical methods, and the positive electrode sheet of lithium iron phosphate is used as the material to be processed.
[0048] S2. The lithium iron phosphate positive electrode sheet to be treated is calcined at 450°C for 2 hours under an argon protective atmosphere to deactivate and carbonize the organic matter or binder in the active material. Then, the lithium iron phosphate powder is separated from the electrode sheet by shaking and then manually ground. The lithium iron phosphate powder is then sieved through a 100-mesh sieve to obtain black powder of positive electrode active material. The black powder is then calcined at 700°C for 2 hours under an oxygen atmosphere to obtain red powder to be treated.
[0049] S3. Dissolve the red powder to be treated in acetone at a solid-liquid ratio of 5g:30ml, and add lithium hydroxide and lithium dihydrogen phosphate to the solution according to a Li:Fe:P molar ratio of 1.05:1:1. Then add 25% sucrose to the mixture, and ball mill the mixture for 10 hours at a speed of 400r / min. After drying, the mixture to be treated is obtained.
[0050] S4. The mixture to be treated is placed in a tube furnace and calcined in an argon protective atmosphere at a temperature of 800℃ for 5 hours to finally obtain recycled lithium iron phosphate cathode material.
[0051] Example 2
[0052] Example 2 provides a regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process, including the following steps:
[0053] S1. After dismantling the waste lithium iron phosphate batteries, the positive electrode sheet and the negative electrode graphite sheet of lithium iron phosphate are separated by mechanical methods, and the positive electrode sheet of lithium iron phosphate is used as the material to be processed.
[0054] S2. The lithium iron phosphate positive electrode sheet to be treated is calcined at 500°C for 1 hour under an argon protective atmosphere to deactivate and carbonize the organic matter or binder in the active material. Then, the lithium iron phosphate powder is separated from the electrode sheet by vibration and then manually ground. The lithium iron phosphate powder is then sieved through a 400-mesh sieve to obtain black powder of positive electrode active material. The black powder is then calcined at 500°C for 3 hours under an oxygen atmosphere to obtain red powder to be treated.
[0055] S3. Dissolve the red powder to be treated in dimethyl carbonate at a solid-liquid ratio of 5g:30ml, and add lithium carbonate and ammonium dihydrogen phosphate to the solution according to a Li:Fe:P molar ratio of 1.05:1:1.05. Then add 20% sucrose to the mixture, and then ball mill the mixture for 16 hours at a speed of 400r / min. After drying, the mixture to be treated is obtained.
[0056] S4. The mixture to be treated is placed in a tube furnace and calcined in an argon or nitrogen protective atmosphere at a temperature of 800°C for 3 hours to finally obtain recycled lithium iron phosphate cathode material.
[0057] Comparative Example 1
[0058] Comparative Example 1 provides a regeneration method for waste lithium iron phosphate cathode material based on a one-pot redox process. The only difference from Example 1 is that the black powder of the cathode active material is not calcined in step S2. Other experimental parameters and conditions are basically the same as those in Example 1, and will not be repeated here.
[0059] Comparative Examples 2-3
[0060] Comparative Examples 2 and 3 respectively provide a regeneration method for repairing waste lithium iron phosphate cathode materials based on a one-pot redox process. Compared with Example 1, the only difference is the amount of organic reducing agent used, which is 15% and 30% respectively. Other experimental parameters and conditions are basically the same as those in Example 1, and will not be repeated here.
[0061] In Comparative Example 1, since the black powder of the positive electrode active material was not subjected to oxidation and calcination treatment, the positive electrode active material still consisted of waste lithium iron phosphate particles with different degrees of failure, particle sizes, carbon contents, and crystal structures. This resulted in uneven repair effects during the subsequent direct regeneration process, leading to poor performance of the regenerated lithium iron phosphate. In contrast, Example 1, through the oxidation and calcination step, transformed the black powder of the positive electrode active material into a uniform phase. The subsequently regenerated lithium iron phosphate particles were uniform, had complete crystal lattices, and exhibited excellent electrochemical performance.
[0062] In Comparative Example 2, the use of 15% reducing agent resulted in incomplete reduction during the subsequent reduction process, and the carbon layer on the surface of the regenerated lithium iron phosphate particles was less, resulting in poor electrochemical performance.
[0063] In Comparative Example 3, the excessive use of reducing agent resulted in excessive carbon content in the regenerated lithium iron phosphate, leading to a decrease in the compaction density of the lithium iron phosphate and an increase in the internal resistance of the battery, which in turn caused a decrease in its capacity.
[0064] Figure 2 These are SEM images of the recycled lithium iron phosphate cathode material and the waste lithium iron phosphate cathode material from Example 1. Figure 2 As shown in a, waste lithium iron phosphate particles contain impurities such as conductive carbon and PVDF, which affect the electrochemical performance of the material. In contrast, recycled lithium iron phosphate particles ( Figure 2 b) is relatively uniform and has a smooth surface.
[0065] Figure 3 These are TEM images of the recycled lithium iron phosphate cathode material and the waste lithium iron phosphate cathode material from Example 1. Figure 3 As shown in Figure a, the surface of waste lithium iron phosphate particles has a disordered carbon layer, which may be due to electrolyte corrosion or mechanical wear. In contrast, recycled lithium iron phosphate particles ( Figure 3 b) The surface is coated with a relatively uniform carbon layer, which is beneficial to improving the electrochemical performance of lithium iron phosphate.
[0066] Figure 4 These are test graphs showing the charge-discharge cycle performance and rate performance of coin cells assembled from recycled lithium iron phosphate cathode materials, waste lithium iron phosphate cathode materials, and commercial lithium iron phosphate cathode materials, as described in Example 1. Figure 4 As shown in Figure a, the electrochemical performance of recycled lithium iron phosphate cathode material is superior to that of spent lithium iron phosphate cathode material; furthermore, at a current density of 0.1C, the electrochemical performance of recycled lithium iron phosphate cathode material is close to that of commercial lithium iron phosphate cathode material, while at high current densities such as 1C, 2C, and 5C, the electrochemical performance of recycled lithium iron phosphate cathode material is superior to that of spent lithium iron phosphate cathode material. Figure 4 b) further demonstrates the effectiveness of this regeneration method.
[0067] Figure 5 The image shows the EIS spectrum of a coin cell assembled from recycled lithium iron phosphate cathode material and waste lithium iron phosphate cathode material in Example 1. It can be seen from the image that the impedance of recycled lithium iron phosphate is significantly lower than that of waste lithium iron phosphate.
[0068] Figure 6 The graphs show the charge-discharge cycle performance and rate performance of coin cells assembled with recycled lithium iron phosphate cathode materials from Examples 1 and Comparative Examples 2-3. It can be seen from the graphs that the electrochemical performance of Example 1 is significantly better than that of Comparative Examples 2-3.
[0069] In summary, the regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process provided by this invention includes the selection of organic reducing agents and organic media. Choosing organic solvents such as acetone as liquid media helps to mix the waste lithium iron phosphate cathode powder with other raw materials more uniformly during high-energy ball milling, thereby aiding in the repair of the lithium iron phosphate lattice. It also includes the selection of raw materials for supplementing elements; choosing raw materials such as lithium dihydrogen phosphate can supplement the missing elements in the waste lithium iron phosphate material without producing environmentally polluting byproducts, making it green and environmentally friendly. Furthermore, it includes the selection of ball milling process parameters; the setting of process parameters makes the particle size of the mixture finer, thereby improving the performance of the regenerated lithium iron phosphate material obtained after high-temperature solid-phase reduction calcination.
[0070] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims
1. A regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process, characterized in that, Includes the following steps: S1. After dismantling the waste lithium iron phosphate batteries, separate the lithium iron phosphate positive electrode sheet and the negative electrode graphite sheet, and use the lithium iron phosphate positive electrode sheet as the material to be processed. S2. After calcining the material to be treated described in step S1 at 300-500°C for 1-2 hours in an inert gas protective atmosphere, the lithium iron phosphate powder is separated from the electrode by oscillation to obtain black powder of positive electrode active material. The black powder is calcined at 500-700°C for 2-3 hours in an oxygen atmosphere to obtain red powder to be treated. S3. The red powder to be treated obtained in step S2 is ball-milled and mixed evenly with organic liquid medium, phosphate, lithium compound and organic reducing agent at room temperature, and then dried to obtain the mixture to be treated; S4. The mixture to be treated obtained in step S3 is subjected to solid-phase reduction calcination in an inert gas protective atmosphere to obtain regenerated lithium iron phosphate cathode material.
2. The regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process according to claim 1, characterized in that, In step S2, the inert gas is argon or nitrogen.
3. The regeneration method for waste lithium iron phosphate cathode materials based on a one-pot redox process according to claim 1, characterized in that, In step S3, the organic liquid medium is one of acetone, butanone, cyclohexanone, methyl ethyl ketone, ethanol, isopropanol, tert-butanol, diethyl ether, methyl propyl ether, tetrahydrofuran, 1,3-dioxolane, ethyl acetate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and polycarbonate.
4. The regeneration method for waste lithium iron phosphate cathode material based on a one-pot redox process according to claim 3, characterized in that, The solid-liquid ratio of the red powder to be treated to the organic liquid medium is 5g:(30-35ml).
5. The regeneration method for waste lithium iron phosphate cathode material based on a one-pot redox process according to claim 4, characterized in that, In step S3, the phosphate is one of lithium dihydrogen phosphate, lithium monohydrogen phosphate, and ammonium dihydrogen phosphate.
6. The regeneration method for waste lithium iron phosphate cathode material based on the one-pot redox method according to claim 5, characterized in that, In step S3, the lithium compound is one of lithium hydroxide, lithium carbonate, lithium phosphate, and lithium oxide.
7. The regeneration method for waste lithium iron phosphate cathode material based on a one-pot redox process according to claim 6, characterized in that, In step S3, the organic reducing agent is one of sucrose, fructose, glucose, β-lactose and maltose, and the amount of the organic reducing agent is 20-25% of the mass of lithium iron phosphate in the material to be treated.
8. The regeneration method for waste lithium iron phosphate cathode material based on a one-pot redox process according to claim 1, characterized in that, In step S3, the ball milling time is 6 to 24 hours and the rotation speed is 400 to 450 r / min.
9. The regeneration method for waste lithium iron phosphate cathode material based on the one-pot redox method according to claim 7, characterized in that, The molar ratio of Li, Fe, and P in the lithium compound, the red powder to be treated, and the phosphate is (1–1.1):1:(0.95–1.05).
10. The regeneration method for waste lithium iron phosphate cathode material based on a one-pot redox process according to claim 1, characterized in that, In step S4, the inert gas is argon or nitrogen; the solid-phase reduction calcination temperature is 500–800°C, and the calcination time is 3–5 hours.