Recycling method of waste lithium iron phosphate positive electrode material and related product

Abstract

According to the recycling and regenerating method of the waste lithium iron phosphate positive electrode material and the related product, the salpeter solution is used for providing a comfortable acid environment in the leaching process, compared with sulfuric acid and the like, the salpeter solution can be recycled at high temperature after being leached, discharge of acid wastewater is reduced, and sustainable development is achieved. And compared with citric acid, formic acid and the like, nitric acid is low in price and better in economic benefit. Oxygen is used as an oxidizing agent in the leaching process, compared with hydrogen peroxide, sodium thiosulfate and other strong oxidizing agents, the oxygen is more economical and safer, and the risk of environmental pollution is reduced. The method is suitable for the waste lithium iron phosphate batteries which are produced by different manufacturers and have certain difference of components and inconsistent discarding degrees, and has the potential of large-scale development, and the regenerated lithium iron phosphate material has the electrochemical level of a commercial material.

Description

Technical Field

[0001] The present application relates to the field of wet recycling of waste lithium-ion batteries, and more specifically, to a method for recycling and regenerating waste lithium iron phosphate cathode materials and related products. Background Art

[0002] At present, traditional fossil energy is gradually exhausted, and a large amount of greenhouse gases are emitted. Lithium-ion batteries, as an important part of clean energy, have attracted people's attention. Lithium-ion batteries are usually classified into layered transition metal oxides, spinel-type, and polyanion-type according to different cathode materials. Among them, the polyanion-type mainly refers to lithium iron phosphate cathode materials. Lithium iron phosphate cathode materials have been widely sought after in the new energy market due to their advantages such as stable structure, long cycle life, and low cost, occupying a large market share.

[0003] The lifespan of lithium iron phosphate batteries is about 5-8 years. Over time, a large number of waste lithium iron phosphate batteries will be retired. Reasonable recycling and utilization of these retired batteries can not only reduce the pressure on environmental protection but also save a large amount of resources. The recycling methods of lithium iron phosphate mainly include pyrometallurgical recycling and direct regeneration recycling. Pyrometallurgical recycling has been basically phased out due to high energy consumption and high emissions of harmful substances. Direct regeneration recycling, as an emerging technology, has been widely sought after, but due to specific repair conditions and repair reagents that often only target batteries with fixed components and a certain degree of waste, it is difficult to develop on a large scale.

[0004] Therefore, it is very important to develop a selective recycling process route that can be recycled and has highly efficient and safe oxidants. Summary of the Invention

[0005] One of the purposes of the present application is to provide a method for recycling and regenerating waste lithium iron phosphate cathode materials to solve the above technical problems.

[0006] Another purpose of the present application is to provide a lithium iron phosphate cathode material obtained by the above method for recycling and regenerating waste lithium iron phosphate cathode materials.

[0007] A further purpose of the present application is to provide a battery whose cathode includes a lithium iron phosphate cathode material prepared by the above method for recycling and regenerating waste lithium iron phosphate cathode materials.

[0008] The present application can be implemented as follows:

[0009] In a first aspect, an embodiment of the present application provides a method for recycling and regenerating waste lithium iron phosphate cathode materials, the method comprising the following steps:

[0010] Step 1: Discharge the used lithium iron phosphate battery in the discharge solution. Under an anaerobic environment, disassemble the discharged battery to obtain the positive electrode plate, and soak the positive electrode plate in an organic solution to obtain a positive electrode material mixture;

[0011] Step 2: Dry the positive electrode material mixture, calcine the dried product under an inert atmosphere, and ball-mill the calcined material to obtain used lithium iron phosphate powder;

[0012] Step 3: Add nitric acid solution to the reactor and heat it to 88 - 98 °C. Then add the used lithium iron phosphate powder obtained in Step 2 to the reactor, introduce oxygen into the reactor, and continuously stir and heat. After the reaction is completed, perform suction filtration to obtain a lithium-rich solution and iron phosphate / carbon slag;

[0013] Step 4: Calcinate the iron phosphate / carbon slag prepared in Step 3 under an oxygen atmosphere to obtain battery-grade iron phosphate;

[0014] Step 5: Add a lithium source and a carbon source to the iron phosphate prepared in Step 4, then add an appropriate amount of absolute ethanol, wet-mill and dry it, and then dry-mill to obtain a lithium iron phosphate precursor;

[0015] Step 6: Calcinate the lithium iron phosphate precursor obtained in Step 5 under an argon atmosphere to obtain a regenerated lithium iron phosphate positive electrode material.

[0016] In a second aspect, an embodiment of the present application provides a lithium iron phosphate positive electrode material, which is prepared by using the above-mentioned recycling and regeneration method of the used lithium iron phosphate positive electrode material.

[0017] In a third aspect, an embodiment of the present application provides a battery, and the battery includes the above-mentioned lithium iron phosphate positive electrode material.

[0018] Compared with the prior art, the recycling and regeneration method and related products of the used lithium iron phosphate positive electrode material provided by the embodiments of the present application provide a comfortable acidic environment with nitric acid solution during the leaching process. Compared with sulfuric acid, etc., nitric acid can be recycled at high temperature after leaching, reducing the discharge of acidic wastewater and achieving sustainable development. And compared with citric acid, formic acid, etc., nitric acid is inexpensive and has better economic benefits. Oxygen is used as an oxidant during the leaching process. Compared with strong oxidants such as hydrogen peroxide and sodium thiosulfate, oxygen is more economical and safe, and reduces the risk of environmental pollution. It is applicable to used lithium iron phosphate batteries with certain differences in components and inconsistent degrees of waste produced by different manufacturers, has the potential for large-scale development, and the regenerated lithium iron phosphate material has the electrochemical level of commercial materials.

[0019] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specific preferred embodiments are given, and in conjunction with the accompanying drawings, the detailed description is as follows. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 This is the XRD pattern of the waste lithium iron phosphate powder provided by the embodiment of the present application.

[0022] Figure 2 This is the XRD pattern of the regenerated lithium iron phosphate material provided by the embodiment of the present application.

[0023] Figure 3 This is the electrochemical performance diagram of the regenerated lithium iron phosphate material in Example 1 provided by the embodiment of the present application. Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0025] In some scenarios, lithium iron phosphate can be recovered by means of wet recycling, and wet recycling is further divided into total element leaching and selective leaching. Total element leaching means that all elements in lithium iron phosphate are dissolved under the action of a strong acid solution, and then the valuable elements are recovered step by step by means of stepwise adjusting the pH. This process will inevitably produce a large amount of acidic and alkaline wastewater and consume a large amount of chemical reagents, which is not friendly to the environment and economic benefits. Selective leaching is to oxidize divalent iron in waste lithium iron phosphate to trivalent iron under the combined action of an oxidant and a weak acidic environment, so that lithium ions are deintercalated from the crystal structure of lithium iron phosphate, while iron phosphate still maintains the olivine structure. At present, most of the published selective leaching recovery technologies for lithium iron phosphate use acid solutions and strong oxidants for recovery, which will inevitably cause great pressure on the environment and economy. Therefore, it is very important to develop a selective recovery process route in which the acid solution can be recycled and the oxidant is highly efficient and safe.

[0026] The present application proposes a method for recycling and regenerating waste lithium iron phosphate cathode materials, including the following steps:

[0027] Step 1: Discharge the used lithium iron phosphate battery in a discharge solution. Under an anaerobic environment, disassemble the discharged battery to obtain the positive electrode sheet, and soak the positive electrode sheet in an organic solution to obtain a positive electrode material mixture.

[0028] Optionally, discharge the used lithium iron phosphate battery in the discharge solution until no bubbles appear at the positive electrode. The discharge duration can be 12 h. Disassemble the discharged battery under an anaerobic environment to avoid spontaneous combustion of the residual lithium metal (negative electrode) with oxygen. When obtaining the positive electrode sheet, a negative electrode sheet, a separator, and a casing will also be obtained. Soak the positive electrode sheet in an organic solution to make the positive electrode material fall off from the current collector to obtain a positive electrode material mixture. Among them, the organic solution uses an equal-volume mixed solution of N, N-dimethylformamide (DMF) and dimethyl carbonate (DMC). DMF is used to dissolve the binder, and DMC is used to dissolve the electrolyte.

[0029] Step 2: Dry the positive electrode material mixture, calcine the dried product under an inert atmosphere, and ball-mill the calcined material to obtain used lithium iron phosphate powder.

[0030] Optionally, the inert atmosphere in Step 2 can be an argon atmosphere or nitrogen. Avoid oxidation during the calcination process. By calcining the dried product under an inert atmosphere, remove the binder.

[0031] Step 3: Add nitric acid solution to the reactor, heat it to 88 - 98 °C, then add the used lithium iron phosphate powder obtained in Step 2 to the reactor, introduce oxygen into the reactor, and continuously stir and heat. After the reaction is completed, perform suction filtration to obtain a lithium-rich solution and iron phosphate / carbon slag.

[0032] During the leaching reaction process in Step 3, lithium is almost 100% deintercalated from the lithium iron phosphate structure.

[0033] It should be noted that if the used lithium iron phosphate powder is directly added to the nitric acid solution when the temperature of the nitric acid solution is relatively low, the iron and phosphorus in it will also dissolve, which will affect the selective leaching effect. In a preferred embodiment, after heating the nitric acid solution to 90 °C, add the used lithium iron phosphate powder obtained in Step 2 to the reactor to make the selective leaching effect better. Introduce oxygen into the reactor, which plays an oxidizing role, with lower cost and higher safety.

[0034] Step 4: Calcine the iron phosphate / carbon slag prepared in Step 3 under an oxygen atmosphere to obtain battery-grade iron phosphate.

[0035] Step 5: Add a lithium source and a carbon source to the iron phosphate prepared in Step 4, then add an appropriate amount of absolute ethanol, wet-mill, dry, and then dry-mill to obtain a lithium iron phosphate precursor.

[0036] Step 6: Calcinate the lithium iron phosphate precursor obtained in Step 5 under an argon atmosphere to obtain the regenerated lithium iron phosphate cathode material.

[0037] In the recycling and regeneration method of waste lithium iron phosphate cathode material provided in this application, the leaching process uses a nitric acid solution to provide a comfortable acidic environment. Compared with sulfuric acid, etc., after nitric acid leaching, it can be recycled at high temperature, reducing the discharge of acidic wastewater and achieving sustainable development. And compared with citric acid, formic acid, etc., nitric acid is inexpensive and has better economic benefits. Oxygen is used as the oxidant in the leaching process. Compared with strong oxidants such as hydrogen peroxide and sodium thiosulfate, oxygen is more economical and safe, and reduces the risk of environmental pollution. It is applicable to waste lithium iron phosphate batteries with certain differences in components produced by different manufacturers and inconsistent degrees of waste, has the potential for large-scale development, and the regenerated lithium iron phosphate material has the electrochemical level of commercial materials.

[0038] In a preferred embodiment, the discharge solution in Step 1 is a 1 mol / L - 2 mol / L sodium chloride solution or a 1 mol / L - 2 mol / L potassium chloride solution (500 ml of discharge solution is used for one soft-pack battery).

[0039] In a preferred embodiment, the pH of the nitric acid solution in Step 3 is 1.60 (which can be replaced by a sulfuric acid solution with a pH of 1.60), and the solid-liquid ratio of the waste lithium iron phosphate powder to the nitric acid solution is 4 g / L.

[0040] The range of the solid-liquid ratio of the waste lithium iron phosphate powder to the nitric acid solution is 3.8 - 4.24 g / L. It should be noted that when the solid-liquid ratio is greater than 4 g / L, the leaching rate of lithium decreases, and the leaching rates of iron and phosphorus remain stable. When the liquid ratio is less than 4 g / L, the leaching rate of lithium is stable, iron and phosphorus dissolve, and the corresponding leaching rates increase, resulting in a worse leaching effect.

[0041] In a preferred embodiment, the heating temperature of the reactor in Step 3 is 90 °C, and the heating and stirring duration is 5 h to 7 h.

[0042] The reactor can be, but is not limited to, a four-necked flask. The reactor can be heated in a water bath. Add the waste lithium iron phosphate powder obtained in Step 2 to the reactor, and introduce oxygen into the reactor to play an oxidizing role, with lower cost and higher safety. Continuously stir and heat (for 5 h or 7 h), and perform suction filtration after the reaction is completed to obtain a lithium-rich solution and iron phosphate / carbon slag.

[0043] Optionally, the obtained lithium-rich solution is further concentrated and then stored. The purpose of concentration is to save storage space.

[0044] In a preferred embodiment, in step 4, the calcination temperature in an oxygen atmosphere is 600 °C to 700 °C, and the heating duration is 6 h to 7 h.

[0045] By calcining in an oxygen atmosphere, after removing residual carbon and water, battery-grade iron phosphate is obtained.

[0046] In a preferred embodiment, the lithium source and carbon source in step 5 are lithium carbonate and glucose. The molar ratio of iron phosphate to lithium carbonate is 1:0.525, and the addition amount of glucose is 10% of the mass of iron phosphate.

[0047] All the obtained iron phosphate is regenerated into lithium iron phosphate cathode material by adding lithium carbonate and glucose and then through carbothermal reduction method.

[0048] Optionally, the lithium iron phosphate cathode material is used to prepare a cathode slurry with acetylene black and PVDF in a mass ratio of 7:2:1 in NMP; the cathode slurry is used to be uniformly coated on an aluminum foil with a thickness of 100 μm to obtain a cathode sheet.

[0049] The features and properties of the present application will be further described in detail below in conjunction with examples.

[0050] Example 1

[0051] (1) Discharge a used lithium iron phosphate battery (used soft-pack battery) in a 2 mol / L sodium chloride solution (for 24 h). In an anaerobic environment, disassemble the discharged battery to obtain a cathode sheet, and soak the cathode sheet in an organic solution to obtain a cathode material mixture.

[0052] (2) Dry the cathode material mixture, calcine the dried product in an inert atmosphere, and ball-mill the calcined material to obtain used lithium iron phosphate powder.

[0053] (3) Add 500 ml of nitric acid solution with a pH of 1.60 to a reactor, heat it to 90 °C, then add 2.0018 g of used lithium iron phosphate powder to the reactor, introduce oxygen into the reactor at a flow rate of 0.5 L / min, and continuously stir and heat (for 5 h). After the reaction is completed, perform suction filtration to obtain a lithium-rich solution and iron phosphate / carbon slag.

[0054] The calculated lithium leaching rate is 100%, and the leaching rates of iron and phosphorus are 0.01% and 7.26% respectively.

[0055] (4) Calcinate the prepared iron phosphate / carbon slag at 600 °C for 6 h in an oxygen atmosphere to obtain battery-grade iron phosphate.

[0056] (5) Add a lithium source and a carbon source to the prepared iron phosphate, then add an appropriate amount of absolute ethanol. After wet grinding, dry it, and then perform dry grinding to obtain a lithium iron phosphate precursor.

[0057] (6) Calcinate the obtained lithium iron phosphate precursor under an argon atmosphere to obtain a regenerated lithium iron phosphate cathode material. Electrochemical tests found that its performance reached the level of commercial materials.

[0058] Example 2

[0059] (1) Discharge a used lithium iron phosphate battery (used soft-pack battery) in a 2 mol / L sodium chloride solution (for 24 h). Under an anaerobic environment, disassemble the discharged battery to obtain the positive electrode plate, and soak the positive electrode plate in an organic solution to obtain a positive electrode material mixture.

[0060] (2) Dry the positive electrode material mixture, calcinate the dried product under an inert atmosphere, and ball-mill the calcined material to obtain used lithium iron phosphate powder.

[0061] (3) Add 500 ml of nitric acid solution with a pH of 2.20 to the reactor, heat it to 90 °C, then add 2.0091 g of used lithium iron phosphate powder to the reactor, introduce oxygen into the reactor at a flow rate of 0.5 L / min, and continuously stir and heat (for 5 h). After the reaction is completed, perform suction filtration to obtain a lithium-rich solution and iron phosphate / carbon slag.

[0062] The calculated leaching rate of lithium is only 35.24%, and the leaching rates of iron and phosphorus are 0.10% and 6.75% respectively. This shows that it is not conducive to the leaching of lithium at a higher pH value.

[0063] Example 3

[0064] (1) Discharge a used lithium iron phosphate battery (used soft-pack battery) in a 2 mol / L sodium chloride solution (for 24 h). Under an anaerobic environment, disassemble the discharged battery to obtain the positive electrode plate, and soak the positive electrode plate in an organic solution to obtain a positive electrode material mixture.

[0065] (2) Dry the positive electrode material mixture, calcinate the dried product under an inert atmosphere, and ball-mill the calcined material to obtain used lithium iron phosphate powder.

[0066] (3) Add 500 ml of nitric acid solution with a pH of 1.60 to the reactor, heat it to 90 °C, then add 1.0016 g of used lithium iron phosphate powder to the reactor, introduce oxygen into the reactor at a flow rate of 0.5 L / min, and continuously stir and heat (for 5 h). After the reaction is completed, perform suction filtration to obtain a lithium-rich solution and iron phosphate / carbon slag.

[0067] The calculated leaching rate of lithium is 97.52%, and the leaching rates of iron and phosphorus are 34.96% and 36.56% respectively. This indicates that too low a solid-liquid ratio will cause a large amount of iron and phosphorus to dissolve, which is not conducive to the selective leaching of lithium.

[0068] Example 4

[0069] (1) Discharge the used lithium iron phosphate battery (used soft-pack battery) in 2 mol / L sodium chloride solution for 24 h. Under an anaerobic environment, disassemble the discharged battery to obtain the positive electrode sheet, and soak the positive electrode sheet in an organic solution to obtain a positive electrode material mixture.

[0070] (2) Dry the positive electrode material mixture, calcine the dried product under an inert atmosphere, and ball-mill the calcined material to obtain used lithium iron phosphate powder.

[0071] (3) Add 500 ml of pure water to the reactor, heat it to 90 °C, then add 2.0056 g of used lithium iron phosphate powder to the reactor, introduce oxygen into the reactor at a flow rate of 0.5 L / min, and continuously stir and heat for 5 h. After the reaction is completed, perform suction filtration to obtain a lithium solution and iron phosphate / carbon slag.

[0072] The calculated leaching rate of lithium is 15.24%, and the leaching rates of iron and phosphorus are 0.38% and 6.81% respectively. This indicates that the oxidative environment provided by nitric acid is the key to constructing the selective leaching system.

[0073] After assembling the regenerated lithium iron phosphate material of Example 1 into a button battery and performing electrochemical tests, it can be seen that its cycling ability is comparable to that of commercial materials after 300 cycles at 2C, indicating that the regenerated material has great commercial competitiveness.

[0074] Please refer to Figure 1 、 Figure 2 and Figure 3 , Figure 1 which is the XRD pattern of the used lithium iron phosphate powder provided in the embodiment of the present application. Figure 2 which is the XRD pattern of the regenerated lithium iron phosphate material provided in the embodiment of the present application. Figure 3 which is the electrochemical performance diagram of the regenerated lithium iron phosphate material in Example 1 provided in the embodiment of the present application.

[0075] From Figure 1 it can be seen that the used lithium iron phosphate material is a mixture of lithium iron phosphate phase and iron phosphate phase. This is because during the long-term cycling process, part of the lithium is lost in the negative electrode and electrolyte, resulting in the irreversible formation of iron phosphate on the surface of lithium iron phosphate.

[0076] From Figure 2It can be seen that the regenerated lithium iron phosphate is a pure-phase lithium iron phosphate cathode material, indicating that the lithium intercalation is perfectly achieved during the regeneration process.

[0077] This application also provides a lithium iron phosphate cathode material, which is prepared by using the above-mentioned recycling and regeneration method of waste lithium iron phosphate cathode material.

[0078] In addition, this application also provides a battery. The positive electrode of this battery is the lithium iron phosphate cathode material obtained by the above-mentioned recycling and regeneration method based on waste lithium iron phosphate cathode material. It is configured into a positive electrode slurry with acetylene black and PVDF in a mass ratio of 7:2:1 in NMP; the positive electrode slurry is uniformly coated on the aluminum foil with a thickness of 100 μm to serve as the positive electrode sheet.

[0079] In summary, for the recycling and regeneration method of waste lithium iron phosphate cathode material and related products provided in this application embodiment, the leaching process uses a nitric acid solution to provide a comfortable acidic environment. Compared with sulfuric acid, etc., nitric acid can be recycled at high temperature after leaching, reducing the discharge of acidic wastewater and achieving sustainable development. And compared with citric acid, formic acid, etc., nitric acid has a lower price and better economic benefits. Oxygen is used as the oxidant in the leaching process. Compared with strong oxidants such as hydrogen peroxide and sodium thiosulfate, oxygen is more economical and safe, and reduces the risk of environmental pollution. It is applicable to waste lithium iron phosphate batteries with certain differences in components and different degrees of waste produced by different manufacturers, has the potential for large-scale development, and the regenerated lithium iron phosphate material has the electrochemical level of commercial materials.

[0080] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for recycling waste lithium iron phosphate positive electrode materials, characterized in that: The method comprises the following steps: Step 1, discharging the waste lithium iron phosphate battery in a discharge solution, disassembling the discharged battery in an oxygen-free environment to obtain a positive electrode sheet, and soaking the positive electrode sheet in an organic solution to obtain a positive electrode material mixed solution; Step 2, drying the positive electrode material mixed solution, calcining the dried product under an inert atmosphere, and ball milling the calcined material to obtain waste lithium iron phosphate powder; Step 3, adding a nitric acid solution into a reactor and heating it to 88-98° C., adding the waste lithium iron phosphate powder obtained in step 2 into the reactor, introducing oxygen into the reactor, and continuously stirring and heating, and filtering after the reaction is completed to obtain a lithium-rich solution and iron phosphate / carbon slag; Step 4, calcining the iron phosphate / carbon slag prepared in step 3 under an oxygen atmosphere to obtain battery-grade iron phosphate; Step 5, adding a lithium source and a carbon source to the iron phosphate prepared in step 4, and then adding an appropriate amount of anhydrous ethanol, wet grinding, drying, and dry grinding to obtain a lithium iron phosphate precursor; Step 6, calcining the lithium iron phosphate precursor obtained in step 5 under an argon atmosphere to obtain a regenerated lithium iron phosphate positive electrode material.

2. The method for recycling waste lithium iron phosphate positive electrode material according to claim 1, characterized in that: The discharge solution in step 1 is 1 mol / L sodium chloride solution or 1 mol / L potassium chloride solution.

3. The method for recycling waste lithium iron phosphate positive electrode material according to claim 1, characterized in that: The pH of the nitric acid solution in step 3 is 1.60, and the solid-to-liquid ratio of the waste lithium iron phosphate powder to the nitric acid solution is 4 g / L.

4. The method for recycling waste lithium iron phosphate positive electrode materials according to claim 1, characterized in that: In step 3, the heating temperature of the reactor is 90° C., and the heating and stirring time is 5 to 7 hours.

5. The method for recycling waste lithium iron phosphate positive electrode material according to claim 1, characterized in that: In step 4, the calcination temperature under oxygen atmosphere is 600° C. to 700° C., and the heating time is 6 h to 7 h.

6. The method for recycling waste lithium iron phosphate positive electrode materials according to claim 1, characterized in that: The lithium source and carbon source in step 5 are lithium carbonate and glucose, the molar ratio of iron phosphate to lithium carbonate is 1:0.525, and the added amount of glucose is 10% of the mass of iron phosphate.

7. The method for recycling waste lithium iron phosphate positive electrode materials according to claim 1, characterized in that: The lithium iron phosphate positive electrode material is used to be configured with acetylene black and PVDF in a mass ratio of 7:2:1 to form a positive electrode slurry; the positive electrode slurry is used to be evenly coated on an aluminum foil in a thickness of 100 μm to obtain a positive electrode sheet.

8. A lithium iron phosphate positive electrode material, characterized in that: The waste lithium iron phosphate positive electrode material is prepared by the recycling and regeneration method according to any one of claims 1 to 7.

9. A battery, characterized in that: The battery comprises the lithium iron phosphate positive electrode material according to claim 8.

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