Regeneration method of waste lithium iron phosphate and regenerated lithium iron phosphate

Abstract

The invention belongs to the technical field of regeneration of waste storage battery positive electrode materials, and particularly relates to a regeneration method of waste lithium iron phosphate and regenerated lithium iron phosphate. The regeneration method of the waste lithium iron phosphate provided by the invention comprises the following steps: mixing a waste lithium iron phosphate positive electrode material containing PVDF, an alkaline lithium source, an iron source and an accelerant, and then sequentially carrying out two stages of calcination treatment in a non-oxidizing atmosphere: in the first stage of calcination treatment, enabling the accelerant to promote the combination of iron and fluorine to generate iron trifluoride; second-stage calcination treatment is carried out to complete carbonization and lithium supplementation of PVDF; the accelerant is ammonium salt. According to the present invention, the reaction between the fluorine generated by PVDF pyrolysis and the iron source is promoted by using the accelerator to generate iron trifluoride so as to inhibit the generation of lithium fluoride, such that the iron trifluoride doping modification is achieved, the hydrocarbon component generated by PVDF pyrolysis is carbonized to form the carbon layer so as to improve the conductivity, and the obtained regenerated lithium iron phosphate has excellent specific capacity and excellent cycle performance.

Description

Technical Field

[0001] The present invention relates to the technical field of the regeneration of waste battery cathode materials, and particularly relates to a regeneration method for waste lithium iron phosphate and regenerated lithium iron phosphate. Background Art

[0002] With the progress and development of technology, new energy has become the trend of future development, and the use of tools such as electric vehicles has increased significantly. Therefore, the demand for secondary batteries has also increased sharply. Compared with lead-acid, Ni-Cd, and Ni-MH batteries, lithium-ion batteries are currently widely used due to their advantages such as high specific energy, long cycle life, good rate performance, low self-discharge, and environmental friendliness. Among them, lithium-ion secondary batteries with lithium iron phosphate as the cathode material have been widely used in power batteries for electric tools and electric vehicles due to their low cost and good safety performance. Although lithium-ion batteries do not contain highly toxic heavy metal elements such as mercury, cadmium, and lead, substances such as the cathode and anode materials and electrolyte solution of lithium-ion batteries still have a certain impact on the environment and human health. With the increasing use of electric tools such as electric vehicles, the recycling and treatment of lithium-ion batteries urgently need to attract the attention of the industry.

[0003] Research has found that the main reasons for the failure of lithium iron phosphate materials are the loss of active lithium and the destruction of the crystal structure, such as the loss of lithium elements, lithium-iron inversion, carbon layer rupture, and particle microcracking. The Chinese patent application with the publication number CN119390033A published on February 7, 2025, discloses a method for recovering PVDF-containing cathode materials from waste lithium iron phosphate batteries and preparing fluorine-doped lithium iron phosphate. The waste lithium iron phosphate batteries are discharged and disassembled, and the cathode sheets are separated. The cathode sheets are soaked in hot water, and the PVDF-containing failed lithium iron phosphate cathode materials and aluminum foils are separated. The PVDF-containing failed lithium iron phosphate cathode materials are calcined with LiOH in a non-oxidizing atmosphere to obtain fluorine-doped lithium iron phosphate. The strong alkaline effect of LiOH promotes the degradation of PVDF and reacts with hydrogen fluoride generated by the pyrolysis of PVDF to form lithium fluoride, thereby doping and modifying lithium iron phosphate. Moreover, LiOH as a lithium source can compensate for the loss of lithium source during the charge and discharge process of lithium iron phosphate, realizing the efficient repair of the failed lithium iron phosphate cathode materials.

[0004] However, the specific capacity and cycle performance of the above-obtained fluorine-doped lithium iron phosphate are still poor, and the first discharge specific capacity at 0.1C is only 146.3 mAh / g. Summary of the Invention

[0005] The purpose of the present invention is to provide a regeneration method for waste lithium iron phosphate to solve the problems of poor specific capacity and cycle performance existing in the prior art when repairing lithium iron phosphate cathode materials.

[0006] The second object of the present invention is to provide a regenerated lithium iron phosphate, which solves the problems of poor specific capacity and cycling performance of the lithium iron phosphate obtained by the existing technology for repair.

[0007] In order to solve the above technical problems, the technical solution of the regeneration method of waste lithium iron phosphate of the present invention is as follows: A regeneration method of waste lithium iron phosphate cathode material, comprising the following steps: mixing a waste lithium iron phosphate cathode material containing PVDF, an alkaline lithium source, an iron source, and a promoter, and then performing calcination treatment in a non-oxidizing atmosphere in two stages. The first-stage calcination treatment enables the promoter to promote the combination of iron and fluorine to generate iron trifluoride, and the second-stage calcination treatment completes the carbonization of PVDF and lithium supplementation; the promoter is an ammonium salt.

[0008] The present invention improves the existing technology and provides a regeneration method of waste lithium iron phosphate. By using a waste lithium iron phosphate cathode material, an alkaline lithium source, an iron source, and a promoter for calcination treatment in two stages, during the first-stage calcination treatment, fluorine generated by the decomposition of PVDF under alkaline conditions combines with the iron source to in-situ generate iron trifluoride. The ammonium salt promoter can promote the combination of iron and fluorine to generate iron trifluoride, inhibit the tendency of fluorine to combine with lithium to form lithium fluoride, and the generated iron trifluoride crystals are coated on the periphery of the lithium iron phosphate crystals. During the second-stage calcination treatment, the hydrocarbon components generated by the decomposition of PVDF are carbonized and in-situ coated on the surfaces of the iron trifluoride and lithium iron phosphate crystals, so that the original broken carbon layer can be repaired, and the generated carbon layer functions as a conductive agent, which helps to improve the conductivity of the cathode material. At the same time, lithium ions are filled into the lithium-deficient pores of the lithium iron phosphate crystal structure to achieve lithium supplementation, and the lithium-iron inverse structure is reformed at high temperature, so that the defective lithium iron phosphate crystal structure can be repaired.

[0009] The regeneration method of waste lithium iron phosphate of the present invention not only realizes the repair of the lithium iron phosphate material, but also realizes the resource utilization of PVDF. The obtained regenerated lithium iron phosphate has excellent specific capacity and cycling performance. The specific capacity can reach more than 153 mAh / g, and the capacity retention rate after 50 cycles can reach more than 98.8%.

[0010] In order to further improve the uniformity of raw material mixing, improve product consistency, and further improve the cycling performance of the regenerated lithium iron phosphate, preferably, the mixing is that a waste lithium iron phosphate cathode material containing PVDF, an alkaline lithium source, an iron source, and a promoter are mixed in a solvent and then the solvent is removed. The addition amount of the solvent is 30-50% of the mass of the waste lithium iron phosphate cathode material.

[0011] In order to further regulate the doping amount of iron trifluoride and the conductivity of the carbon layer, preferably, the content of PVDF in the waste lithium iron phosphate cathode material is 0.5-3%.

[0012] To further regulate the doping amount of iron trifluoride and improve the filling of lithium ions, preferably, the addition amounts of the alkaline lithium source, iron source, and promoter are 1-5%, 0.4-3%, and 0.4-1% of the mass of the waste lithium iron phosphate cathode material, respectively. The addition amount of the iron source is adjusted according to the content of polyvinylidene fluoride (PVDF). More preferably, the molar ratio of iron to fluorine element is (0.94-1):3.

[0013] To further promote the combination of iron and fluorine to form iron trifluoride, preferably, the ammonium salt is selected from one or two of ammonium bicarbonate and ammonium carbonate. The ammonium salt promoter can promote the combination of iron and fluorine to form iron trifluoride. If the ammonium salt promoter is not added, fluorine is more inclined to combine with lithium to form lithium fluoride instead of iron trifluoride.

[0014] To fully decompose PVDF to generate fluorine and hydrocarbon components, and further make the decomposed fluorine and iron fully combine and react, and completely carbonize the hydrocarbon components, preferably, the temperature of the first-stage calcination treatment is 200-300 °C, and the time of the first-stage calcination treatment is 6-8 h; the temperature of the second-stage calcination treatment is 600-800 °C, and the time of the second-stage calcination treatment is 8-14 h.

[0015] To further improve the mixing uniformity, preferably, the mixing is carried out by ball milling, and the time of the ball milling is 60-100 min. Ball milling can crush each material to the nanoscale, and the nanoscale particles are mixed together more efficiently and fully during the subsequent calcination reaction.

[0016] To further improve the specific capacity and cycling performance of the cathode material, preferably, the alkaline lithium source is selected from one or two of lithium hydroxide and lithium oxide; the iron source is selected from one or two of iron(III) oxide and iron(III) hydroxide.

[0017] To further improve the solvent removal efficiency, preferably, the solvent removal is drying at 100-150 °C for 1-3 h.

[0018] The technical solution for the regeneration of lithium iron phosphate of the present invention is: A regenerated lithium iron phosphate prepared by a regeneration method of waste lithium iron phosphate, wherein the regenerated lithium iron phosphate contains 0.5-3% of iron trifluoride.

[0019] The regenerated lithium iron phosphate of the present invention is prepared by the regeneration method of waste lithium iron phosphate. Through two-stage calcination treatment of the raw materials, PVDF is decomposed to generate fluorine, which reacts with iron to form iron trifluoride and coats the periphery of the lithium iron phosphate crystal. The carbon and hydrogen components generated by decomposition are carbonized to form a carbon coating layer to improve conductivity, and lithium ions are filled into the lithium iron phosphate crystal to achieve lithium supplementation. The obtained regenerated lithium iron phosphate has excellent specific capacity and cycling performance, with a specific capacity of more than 153 mAh / g and a capacity retention rate of more than 98.8% after 50 cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 XRD pattern of the regenerated lithium iron phosphate obtained by the regeneration method of waste lithium iron phosphate in Example 1 of the present invention; Figure 2 XRD pattern of the regenerated lithium iron phosphate obtained by the regeneration method of waste lithium iron phosphate in Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0021] The technical concept of the regeneration method of waste lithium iron phosphate of the present invention is as follows: The prior art dopes and modifies lithium iron phosphate by generating lithium fluoride from the fluorine produced by the pyrolysis of PVDF and a lithium source to supplement the lithium loss of lithium iron phosphate; while the present invention uses a promoter to promote the reaction of the fluorine produced by the pyrolysis of PVDF with an iron source to form iron trifluoride and inhibit the formation of lithium fluoride, dopes and modifies lithium iron phosphate with iron trifluoride, and the carbon and hydrogen components generated by the pyrolysis of PVDF are carbonized to form a carbon coating layer to improve conductivity. The obtained regenerated lithium iron phosphate has excellent specific capacity and cycling performance.

[0022] The regeneration method of waste lithium iron phosphate of the present invention includes the following steps: Mix the waste lithium iron phosphate cathode material containing PVDF, an alkaline lithium source, an iron source, and a promoter in a solvent by ball milling. The ball milling time is 60 - 100 min, the content of PVDF in the waste lithium iron phosphate cathode material is 0.5 - 3%, and the addition amounts of the alkaline lithium source, the iron source, and the promoter are 1 - 5%, 0.4 - 3%, and 0.4 - 1% of the mass of the waste lithium iron phosphate cathode material respectively. The promoter is an ammonium salt, and the addition amount of the solvent is 30 - 50% of the mass of the waste lithium iron phosphate cathode material; then dry at 100 - 150 °C for 1 - 3 h to remove the solvent; perform two-stage calcination treatment in a non-oxidizing atmosphere. The temperature of the first-stage calcination treatment is 200 - 300 °C, and the time of the first-stage calcination treatment is 6 - 8 h. The temperature of the second-stage calcination treatment is 600 - 800 °C, and the time of the second-stage calcination treatment is 8 - 14 h.

[0023] In a specific embodiment, the waste lithium iron phosphate cathode material containing PVDF is obtained by removing the aluminum foil from the waste lithium battery cathode sheet through hot water ultrasonic treatment.

[0024] In a specific embodiment, the non-oxidizing atmosphere is nitrogen or argon.

[0025] In a specific embodiment, the solvent is selected from one or more of benzene, toluene, xylene, cyclohexane, and cyclopentane.

[0026] The following further illustrates the embodiments of the present invention in conjunction with specific examples. The chemical reagents involved in the following examples are all commercially available conventional products unless otherwise specified.

[0027] I. Specific examples of the regeneration method of waste lithium iron phosphate of the present invention and regenerated lithium iron phosphate Example 1 The regeneration method of waste lithium iron phosphate in this example is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF after removing the aluminum foil is 1.68 wt%. Add 15.0 g of lithium hydroxide, 6.71 g of iron(III) oxide, and 4.5 g of ammonium bicarbonate to 200 g of toluene and stir to mix evenly. Then add 500 g of the waste lithium iron phosphate cathode material containing PVDF and ball mill for 60 min. Wet ball milling can crush each material to the nanoscale and mix them more evenly, which is beneficial for more efficient and sufficient subsequent calcination reactions. After ball milling, transfer it to a forced-air drying oven and dry at 120 °C for 2.5 h to remove toluene. Then transfer it to a muffle furnace and heat up to 260 °C, and keep it in a nitrogen atmosphere for 6 h to enable the promoter to promote the combination of iron and fluorine decomposed from PVDF to form iron(III) fluoride. Then heat up to 750 °C and keep it in a nitrogen atmosphere for 10 h to enable the hydrocarbon components generated by the decomposition of PVDF to be carbonized and in-situ coated on the surfaces of iron(III) fluoride and lithium iron phosphate crystals. At the same time, lithium ions are filled into the lithium-deficient pores in the lithium iron phosphate crystal structure to achieve lithium supplementation, and then cool down to obtain regenerated lithium iron phosphate. The XRD pattern of the regenerated lithium iron phosphate in this example is as Figure 1 shown, where the abscissa is the 2θ angle and the ordinate is the relative intensity. Figure 1 The characteristic peaks of iron(III) fluoride corresponding to 2θ = 24° and 25° in 1 and 2 respectively prove the formation of iron(III) fluoride.

[0028] The regenerated lithium iron phosphate obtained by the regeneration method in this example is the regenerated lithium iron phosphate of the present invention. The regenerated lithium iron phosphate contains 1.9% of iron(III) fluoride. The test method for the content of iron(III) fluoride is as follows: Melt the regenerated lithium iron phosphate product obtained in this example with excessive sodium carbonate at 900 °C to convert iron(III) fluoride into sodium fluoride, then dissolve it in water to remove the insoluble substances, and then use the fluoride ion selective electrode method to measure the fluoride ion concentration in the solution and calculate the mass of iron(III) fluoride.

[0029] Example 2 The regeneration method of waste lithium iron phosphate in this example is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF with aluminum foil removed used is 2.51 wt%. Add 23.0 g of lithium hydroxide, 9.81 g of iron(III) oxide, and 5.0 g of ammonium bicarbonate to 250 g of toluene, stir and mix evenly, then add 500 g of the waste lithium iron phosphate cathode material containing PVDF and ball mill for 60 min. Transfer it to a forced-air drying oven and dry at 140 °C for 1 h to remove toluene. Then transfer it to a muffle furnace, heat up to 300 °C, keep it under a nitrogen atmosphere for 8 h, then heat up to 700 °C, keep it under a nitrogen atmosphere for 8 h, and cool down to obtain regenerated lithium iron phosphate.

[0030] The regenerated lithium iron phosphate obtained by the regeneration method of this example is the regenerated lithium iron phosphate of the present invention, and the regenerated lithium iron phosphate contains 2.77% of iron trifluoride.

[0031] Example 3 The regeneration method of waste lithium iron phosphate in this example is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF with aluminum foil removed used is 0.51 wt%. Add 6.0 g of lithium hydroxide, 2.1 g of iron(III) oxide, and 2.4 g of ammonium bicarbonate to 150 g of cyclohexane, stir and mix evenly, then add 500 g of the waste lithium iron phosphate cathode material containing PVDF and ball mill for 60 min. Transfer it to a forced-air drying oven and dry at 100 °C for 2 h to remove cyclohexane. Then transfer it to a muffle furnace, heat up to 280 °C, keep it under a nitrogen atmosphere for 7 h, then heat up to 650 °C, keep it under a nitrogen atmosphere for 14 h, and cool down to obtain regenerated lithium iron phosphate.

[0032] The regenerated lithium iron phosphate obtained by the regeneration method of this example is the regenerated lithium iron phosphate of the present invention, and the regenerated lithium iron phosphate contains 0.59% of iron trifluoride.

[0033] Example 4 The regeneration method of waste lithium iron phosphate in this example is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF with aluminum foil removed used is 2.04 wt%. Add 10.0 g of lithium oxide, 11.35 g of iron(III) hydroxide, and 3.0 g of ammonium carbonate to 200 g of benzene, stir and mix evenly, then add 500 g of the waste lithium iron phosphate cathode material containing PVDF and ball mill for 60 min. Transfer it to a forced-air drying oven and dry at 100 °C for 2 h to remove benzene. Then transfer it to a muffle furnace, heat up to 300 °C, keep it under an argon atmosphere for 6 h, then heat up to 660 °C, keep it under an argon atmosphere for 12 h, and cool down to obtain regenerated lithium iron phosphate.

[0034] The regenerated lithium iron phosphate obtained by the regeneration method of this embodiment is the regenerated lithium iron phosphate of the present invention, and the regenerated lithium iron phosphate contains 2.30% iron trifluoride.

[0035] II. Comparative Examples Comparative Example 1 The regeneration method of the waste lithium iron phosphate in this comparative example is basically the same as that of Example 1, except that: no promoter is used. The specific method is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF from which the aluminum foil has been removed is 1.68 wt%. 15.0 g of lithium hydroxide and 6.71 g of ferric oxide are added to 200 g of toluene and stirred and mixed evenly, then 500 g of the waste lithium iron phosphate cathode material containing PVDF is added for ball milling for 60 min, transferred to a blast drying oven and dried at 120 °C for 2.5 h to remove toluene, then transferred to a muffle furnace and heated to 260 °C, maintained for 6 h under a nitrogen atmosphere, then heated to 750 °C, maintained for 10 h under a nitrogen atmosphere, and cooled to obtain regenerated lithium iron phosphate.

[0036] Comparative Example 2 The regeneration method of the waste lithium iron phosphate in this comparative example is basically the same as that of Example 1, except that: no solvent is used. The specific method is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF from which the aluminum foil has been removed is 1.68 wt%. 15.0 g of lithium hydroxide, 6.71 g of ferric oxide, 4.5 g of ammonium bicarbonate and 500 g of the waste lithium iron phosphate cathode material containing PVDF are ball milled for 60 min, transferred to a muffle furnace and heated to 260 °C, maintained for 6 h under a nitrogen atmosphere, then heated to 750 °C, maintained for 10 h under a nitrogen atmosphere, and cooled to obtain regenerated lithium iron phosphate.

[0037] Comparative Example 3 The regeneration method of the waste lithium iron phosphate in this comparative example is basically the same as that of Example 1, except that: no iron source, promoter and solvent are used. The specific method is as follows: The PVDF content in the waste lithium iron phosphate cathode material containing PVDF from which the aluminum foil has been removed is 1.68 wt%. 15.0 g of lithium hydroxide and 500 g of the waste lithium iron phosphate cathode material containing PVDF are ball milled for 60 min, transferred to a muffle furnace and heated to 260 °C, maintained for 6 h under a nitrogen atmosphere, then heated to 750 °C, maintained for 10 h under a nitrogen atmosphere, and cooled to obtain regenerated lithium iron phosphate. The XRD pattern of the regenerated lithium iron phosphate in this comparative example is as Figure 2 shown, and from Figure 2 it can be seen that the characteristic peaks of iron trifluoride do not appear at 2θ = 24° and 25°.

[0038] III. Experimental Examples The regenerated lithium iron phosphate prepared in the examples and comparative examples was made into button cells, and electrical performance tests were carried out. The specific capacity and cycle performance test results are shown in Table 1.

[0039] Table 1 Electrical properties of the regenerated iron phosphate prepared in the examples and comparative examples As can be seen from Table 1, compared with not using a promoter (Comparative Example 1), the initial specific capacity of the regenerated lithium iron phosphate in Example 1 is higher, indicating that the addition of the promoter in the regeneration method of the present invention can promote the formation of iron trifluoride, thereby increasing the specific capacity of the regenerated lithium iron phosphate; compared with not using a solvent (Comparative Example 2), the capacity retention rate of the regenerated lithium iron phosphate in Example 1 after 50 cycles is higher, indicating that the addition of the solvent can improve the uniformity of raw material mixing, improve product consistency, and thereby improve the cycle performance; compared with only calcining with an alkaline lithium source without using an iron source, a promoter, and a solvent (Comparative Example 3), both the initial specific capacity and the capacity retention rate of the regenerated lithium iron phosphate in Example 1 after 50 cycles have been improved, indicating that the specific capacity and cycle retention rate of the regenerated lithium iron phosphate obtained by only calcining with an alkaline lithium source are poor. In addition, compared with Comparative Example 3, the initial specific capacity and the capacity retention rate of the regenerated lithium iron phosphate in Comparative Example 2 after 50 cycles are both higher, indicating that compared with only calcining with an alkaline lithium source, the dry ball milling without using a solvent when introducing an iron source and an ammonium salt promoter can further improve the initial specific capacity and cycle performance of the battery.

[0040] The regenerated lithium iron phosphate obtained by the regeneration method of waste lithium iron phosphate provided by the present invention has excellent specific capacity and cycle performance. The specific capacity reaches more than 153 mAh / g, and the capacity retention rate after 50 cycles reaches more than 98.8%.

[0041] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A regeneration method for waste lithium iron phosphate, characterized in that, It includes the following steps: Mix the waste lithium iron phosphate cathode material containing PVDF, alkaline lithium source, iron source, and promoter, and then conduct calcination treatment in two stages in a non-oxidizing atmosphere. The first-stage calcination treatment enables the promoter to promote the combination of iron and fluorine to form iron trifluoride, and the second-stage calcination treatment completes the carbonization of PVDF and lithium supplementation; the promoter is an ammonium salt.

2. The regeneration method of waste lithium iron phosphate as described in claim 1, characterized in that, The mixing is to mix the waste lithium iron phosphate cathode material containing PVDF, alkaline lithium source, iron source, and promoter in a solvent and then remove the solvent. The addition amount of the solvent is 30-50% of the mass of the waste lithium iron phosphate cathode material.

3. The regeneration method of waste lithium iron phosphate as claimed in claim 1, wherein The content of PVDF in the waste lithium iron phosphate cathode material is 0.5-3%.

4. The regeneration method of waste lithium iron phosphate as claimed in claim 1, wherein The addition amounts of the alkaline lithium source, iron source, and promoter are 1-5%, 0.4-3%, and 0.4-1% of the mass of the waste lithium iron phosphate cathode material, respectively.

5. The regeneration method of waste lithium iron phosphate as described in any one of claims 1-4, characterized in that, The ammonium salt is selected from one or both of ammonium bicarbonate and ammonium carbonate.

6. The regeneration method of waste lithium iron phosphate as described in any one of claims 1-4, characterized in that, The temperature of the first-stage calcination treatment is 200-300°C, and the time of the first-stage calcination treatment is 6-8 h; the temperature of the second-stage calcination treatment is 600-800°C, and the time of the second-stage calcination treatment is 8-14 h.

7. The regeneration method of waste lithium iron phosphate according to claim 2, characterized in that, The mixing is carried out by ball milling, and the time of the ball milling is 60-100 min.

8. The regeneration method of waste lithium iron phosphate as described in any one of claims 1-4, characterized in that, The alkaline lithium source is selected from one or both of lithium hydroxide and lithium oxide; the iron source is selected from one or both of iron(III) oxide and iron(III) hydroxide.

9. The regeneration method of waste lithium iron phosphate according to claim 2, wherein The removal of the solvent is to dry at 100-150°C for 1-3 h.

10. A regenerated lithium iron phosphate prepared by the regeneration method of waste lithium iron phosphate according to any one of claims 1-9, characterized in that, The regenerated lithium iron phosphate contains 0.5-3% of iron trifluoride.

Images