Method for regenerating lithium iron phosphate positive electrode material by using battery electrolyte

Abstract

The invention discloses a method for regenerating a lithium iron phosphate positive electrode material by using a battery electrolyte. The method comprises the following steps: pretreating a waste lithium iron phosphate battery to obtain a waste lithium iron phosphate positive electrode plate and an electrolyte; the method comprises the following steps: carrying out high-temperature calcination on a waste lithium iron phosphate positive plate to remove a binder, grinding to obtain waste lithium iron phosphate positive powder, pressing the obtained positive powder into sheets by a tablet press, and putting the sheets into a sleeve; in the regeneration process, an electrolyte is sprayed into the tubular furnace through an atomizer to be in contact with the positive electrode material, and the lithium iron phosphate positive electrode material is regenerated; the waste battery electrolyte is used as a lithium salt, a reducing agent and a carbon source at the same time in the high-temperature process, and the waste lithium iron phosphate battery positive electrode material is regenerated; according to the method, the waste lithium iron phosphate positive electrode material can be successfully regenerated, a feasible thought is provided for reutilization of the electrolyte, and the method is a green and efficient technology.

Description

Technical Field

[0001] The invention relates to a waste battery repair technology, and in particular to a method for regenerating lithium iron phosphate positive electrode materials from battery electrolyte. Background Art

[0002] Lithium-ion batteries have become an indispensable part of social life. Compared with lead-acid batteries, nickel-cadmium batteries, and nickel-metal hydride batteries, lithium-ion batteries have the advantages of high energy density, no memory effect, long cycle performance, and high operating voltage. They have been widely used in energy storage, automobiles, electronics and other fields. Among them, lithium iron phosphate batteries have developed rapidly in recent years and occupied a large market share due to their advantages such as high operating voltage, high energy density, long cycle life, good safety performance, low self-discharge rate, and no memory effect. However, lithium-ion batteries will face the problem of retirement after a certain period of use. Therefore, the reasonable disposal of waste lithium-ion batteries is imminent.

[0003] Direct regeneration is one of the most common ways to treat spent lithium-ion batteries. It is mainly used for positive electrodes containing precious metals. For lithium iron phosphate batteries, the main reasons for the failure of the positive electrode include the lack of lithium ions, the occupation of Li sites by Fe and the resulting Fe Li The emergence of anti-sites and Fe 3+ Therefore, the current regeneration of lithium iron phosphate positive electrode is mainly repaired at high temperature by adding additional lithium source and reducing agent. In order to improve the electrochemical performance of lithium iron phosphate batteries, some additional carbon compounds are added to enhance its conductivity by decomposing the carbon compounds at high temperature and coating them on the surface of the positive electrode material.

[0004] Although the above methods can repair waste lithium iron phosphate positive electrode materials, the additional addition of lithium sources, reducing agents and even carbon sources greatly increases the recycling cost, which goes against the original intention of battery recycling. In addition, electrolytes are indispensable in lithium-ion batteries. Electrolytes are generally composed of lithium salts, organic solvents (ethylene carbonate, dimethyl carbonate, etc.) and additives. At present, the recycling methods of electrolytes in industry are relatively mature, and the basic components of the recycled electrolytes will not change significantly. However, there is still a lack of research on the reuse of electrolytes. Therefore, an appropriate method is currently needed to reuse electrolytes. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a method for regenerating lithium iron phosphate positive electrode materials from battery electrolytes. By contacting the electrolyte with the waste lithium iron phosphate positive electrode materials at high temperature, not only can the waste lithium iron phosphate battery positive electrode be regenerated, but also a suitable solution for the reuse of the electrolyte is provided.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for regenerating lithium iron phosphate positive electrode material from battery electrolyte, comprising the following steps:

[0008] 1) Pre-treating waste lithium iron phosphate batteries to obtain waste lithium iron phosphate positive electrode sheets and collecting waste battery electrolytes;

[0009] 2) placing the waste lithium iron phosphate positive electrode sheet in a tube furnace and calcining it at high temperature in an inert atmosphere to remove the binder, separate the positive electrode active material from the aluminum foil, and grind the waste lithium iron phosphate positive electrode powder;

[0010] 3) Pressing the positive electrode powder into lithium iron phosphate positive electrode sheets;

[0011] 4) adding LiPF6 and a composite solvent to the electrolyte recovered in step 1) to prepare an electrolyte of standard concentration;

[0012] 5) placing the lithium iron phosphate positive electrode sheet in a casing and placing it in a tube furnace, and raising the temperature of the tube furnace to a certain temperature under the protection of an inert atmosphere;

[0013] 6) placing the electrolyte prepared in step 5) in an atomizer, and under the protection of an inert atmosphere, introducing the electrolyte into a tubular furnace through the atomizer to contact the lithium iron phosphate positive electrode sheet;

[0014] 7) Raise the temperature in the tube furnace to 650-750°C at 5°C / min under inert atmosphere, and calcine the positive electrode material for 4-8h;

[0015] 8) After calcination, the regenerated lithium iron phosphate positive electrode material is obtained by naturally cooling down.

[0016] Preferably, during the pretreatment of the waste lithium iron phosphate battery in step 1), the waste battery is placed in a 5wt% NaCl solution for discharge, and then disassembled under the protection of an inert atmosphere to obtain a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte.

[0017] Preferably, the disassembly process in step 1) is carried out in a glove box with a water concentration of less than 0.01 ppm and an oxygen concentration of less than 0.01 ppm.

[0018] Preferably, in step 2), the waste lithium iron phosphate positive electrode sheet is calcined at a high temperature of 400° C. to 600° C. for 1 to 2 hours to remove the binder on the surface and separate the positive electrode active material and the aluminum foil.

[0019] Preferably, in step 3), the positive electrode powder is pressed into a sheet with a thickness of 3 to 5 mm under a pressure of 8 T.

[0020] Preferably, the electrolyte LiPF6 concentration configured in the step 4) is 0.5-1.5 mol / L, and the added composite solvent includes ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) in a volume ratio of 1:1:1 or dimethyl carbonate (DMC) and ethylene carbonate (EC) in a volume ratio of 1:1.

[0021] Preferably, in step 5), the temperature of the tube furnace is increased to 200-250°C.

[0022] Preferably, the atomization rate of the electrolyte in step 6) is 3 to 5 mL / min.

[0023] Preferably, the inert atmosphere used in steps 2), 6), 7) and 8) is provided by N2 or Ar.

[0024] Preferably, in step 5), the lithium iron phosphate positive electrode sheet is placed vertically in a sleeve and placed in a tubular furnace.

[0025] The present invention has the following beneficial effects:

[0026] The method of the present invention uses the electrolyte recovered from the old battery as a regeneration agent. During the pyrolysis process, the electrolyte can simultaneously act as a lithium source, a reducing agent, and a carbon conductive agent, thereby achieving the regeneration of waste lithium iron phosphate positive electrode materials and achieving the effect of "killing three birds with one stone". The LiPF6 in the battery electrolyte can be used as a lithium salt to make up for the missing lithium ions, and the gas generated by the pyrolysis of the electrolyte can be used as a reducing agent. In the subsequent high-temperature calcination process of the positive electrode material, the carbon-containing compound in the electrolyte can also act as a carbon conductive agent, ultimately achieving the regeneration of the lithium iron phosphate battery.

[0027] During the calcination process, the lithium salt (LiPF6) contained in the electrolyte can supplement the missing lithium ions in the positive electrode material. In addition, the reducing gas generated by the electrolyte can 3+ Reduction to Fe 2+ , reducing Fe Li In addition, the carbon-containing compounds contained in the electrolyte can also be deposited on the surface of the positive electrode material during the high-temperature calcination process to form a carbon conductive network and enhance the electrochemical properties of the positive electrode material.

[0028] By pressing the positive electrode material and atomizing the electrolyte, it is possible to ensure a more complete contact between the electrolyte and the positive electrode sheet, avoiding pollution and waste caused by the volatilization of the electrolyte solvent. The lithium iron phosphate positive electrode sheet is placed in a sleeve and placed in a tubular furnace. It is preheated under the protection of an inert atmosphere. The atomized electrolyte becomes a liquid with extremely small particles. The tubular furnace is heated in advance to ensure that the atomized electrolyte instantly turns into gas in the tubular furnace, and contacts the electrode sheet together with argon gas, ensuring that the electrolyte mist is fully combined with the electrolyte.

[0029] Compared with the current technology, the present invention uses electrolyte as the only regeneration agent, which can simultaneously achieve lithium replenishment and Fe 3+ The three functions of reduction and carbon coating greatly reduce the regeneration cost and also provide a feasible idea for the reuse of electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of the method of the present invention;

[0031] Figure 2 is a schematic diagram of a lithium iron phosphate positive electrode regeneration device of the present invention;

[0032] Figure 3 It is the SEM image of the positive electrode of the waste lithium iron phosphate battery and the positive electrode of the recycled lithium iron phosphate battery;

[0033] Where a is the positive electrode of the waste lithium iron phosphate battery, and b is the positive electrode of the recycled lithium iron phosphate battery;

[0034] Figure 4 It is the charge and discharge curve of recycled lithium iron phosphate material and waste lithium iron phosphate material at 0.3C. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0036] The present invention provides a method for regenerating lithium iron phosphate positive electrode material from battery electrolyte, for details, see Figure 1 and Figure 2 , including the following steps:

[0037] Step 1: Positive electrode pretreatment:

[0038] 1. Discharge and disassemble the waste lithium iron phosphate battery to obtain the lithium iron phosphate positive electrode sheet and collect the waste battery electrolyte; wherein the waste lithium iron phosphate battery is discharged using a NaCl solution.

[0039] 2. Calcine the waste lithium iron phosphate positive electrode sheet at high temperature in a tube furnace to remove the binder, and obtain the waste lithium iron phosphate positive electrode powder after grinding;

[0040] Preferably, when removing the binder, the high temperature pyrolysis conditions are: a temperature range of 400° C. to 600° C., and a time of 1 h to 2 h.

[0041] 3. Use a tablet press to press the positive electrode powder into lithium iron phosphate positive electrode sheets.

[0042] Preferably, the lithium iron phosphate positive electrode sheet has a thickness of 3 to 5 mm and a diameter of 1.5 cm.

[0043] 4. Place the lithium iron phosphate positive electrode sheet in a casing and place it in a tube furnace.

[0044] Step 2: Electrolyte preparation:

[0045] 5. In a glove box, according to the composition of the recovered electrolyte, add appropriate amounts of LiPF6 and other solvents to prepare an electrolyte with LiPF6 as the lithium salt and two or more of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC) as a composite solvent.

[0046] Preferably, the LiPF6 concentration is 1 mol / L, and the solvent composition is ethylene carbonate (EC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) = 1:1:1 or dimethyl carbonate (DMC): ethylene carbonate (EC) = 1:1.

[0047] Step 3: Regeneration of lithium iron phosphate cathode

[0048] 6. Under the protection of inert atmosphere, raise the temperature of the tube furnace to a certain temperature and maintain it.

[0049] Preferably, the temperature ranges from 200 to 250°C.

[0050] 7. Place the prepared electrolyte in an atomizer. Under the protection of an inert atmosphere, the electrolyte is introduced into a tubular furnace through an atomizer and contacts the lithium iron phosphate positive electrode sheet.

[0051] Preferably, the nebulization rate is 3 to 5 mL / min.

[0052] 8. Under the protection of inert atmosphere, heat the tubular furnace to calcine the positive electrode material.

[0053] Preferably, the calcination temperature is 650-750° C., the heating rate is 5° C. / min, and the calcination time is 4-8 h.

[0054] The present invention is described in detail below with reference to specific embodiments.

[0055] Example 1

[0056] The present embodiment provides a method for regenerating a lithium iron phosphate positive electrode material from a battery electrolyte, comprising the following steps:

[0057] 1. Pretreatment of lithium iron phosphate positive electrode:

[0058] Step 1: The used lithium iron phosphate battery was immersed in a 5wt% NaCl solution for 24 hours to release the residual power, and then placed in an 80°C forced air drying oven for 12 hours.

[0059] Step 2: Manually disassemble the battery in the glove box, collect the positive electrode, diaphragm, negative electrode, and collect the electrolyte of the used battery.

[0060] Step 3: Place the positive electrode sheet in a tube furnace, and under argon protection, heat it to 500°C at a heating rate of 5°C / min and keep it for 2 hours to remove the binder PVDF.

[0061] Step 4: Manually separate the positive electrode active material and the aluminum foil, and grind the positive electrode active material into powder.

[0062] Step 5: Take a portion of the positive electrode active material and place it in a tablet press. Set the tablet press pressure to 8T and keep it at this pressure for 1 minute to obtain a disc with a thickness of 3 mm and a diameter of 1.5 cm.

[0063] Step 6: Place the wafer vertically in a quartz sleeve with an inner diameter of 1.7 cm, and place the quartz sleeve in a tube furnace.

[0064] 2. Electrolyte preparation:

[0065] Step 7: In a glove box, an electrolyte composite solvent is prepared by adding dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC) to the collected electrolyte in a volume ratio of 1:1:1.

[0066] Step 8: Add LiPF6, stir to dissolve, and prepare a 1 mol / L electrolyte solution.

[0067] 3. Lithium iron phosphate cathode regeneration

[0068] Step 9: Under argon protection, heat the tube furnace to 200°C.

[0069] Step 10: Take 10 mL of electrolyte and place it in the atomizer. Adjust the atomization rate to 3 mL / min, atomize the electrolyte into the tubular furnace, and keep it for 30 minutes.

[0070] Step 11: Increase the temperature of the tube furnace to 700°C at a heating rate of 5°C / min and maintain for 6 hours.

[0071] Step 12: After cooling, the regenerated lithium iron phosphate positive electrode material is obtained.

[0072] Figure 3 These are SEM characterization pictures of waste lithium iron phosphate and regenerated lithium iron phosphate, where a is the positive electrode of the waste lithium iron phosphate battery, and b is the positive electrode of the regenerated lithium iron phosphate battery. It can be seen that the surface of the regenerated lithium iron phosphate is smooth and has fewer floc-like impurities, which is beneficial to the improvement of its electrochemical performance.

[0073] CR2032 button cells were used to characterize the electrochemical properties of the synthesized materials.

[0074] First, the positive electrode active material, conductive agent acetylene black, and binder (PVDF mass fraction 10%) were mixed in a mass ratio of 8:1:1, and then an appropriate amount of N-methylpyrrolidone was added as a solvent and stirred thoroughly. The resulting slurry was coated on a copper foil and dried at 120°C under vacuum for 10 hours, and then a disc with a diameter of 12 mm was cut out with a cutting machine, and compacted under 20 MPa to obtain a button battery positive electrode sheet.

[0075] Figure 4 The figure shows the charge and discharge performance of the waste lithium iron phosphate positive electrode and the regenerated lithium iron phosphate positive electrode at 0.3C. As can be seen from the figure, the specific capacity of the regenerated lithium iron phosphate positive electrode exceeds 150mAh / g, which is significantly higher than that of the waste lithium iron phosphate positive electrode.

[0076] Example 2

[0077] The present embodiment provides a method for regenerating a lithium iron phosphate positive electrode material from a battery electrolyte, comprising the following steps:

[0078] 1. Pretreatment of lithium iron phosphate positive electrode:

[0079] Step 1: The used lithium iron phosphate battery was immersed in a 5wt% NaCl solution for 24 hours to release the residual power, and then placed in an 80°C forced air drying oven for 12 hours.

[0080] Step 2: Manually disassemble the battery in the glove box, collect the positive electrode, diaphragm, negative electrode, and collect the electrolyte of the used battery.

[0081] Step 3: Place the positive electrode sheet in a tube furnace, and under argon protection, heat it to 600°C at a heating rate of 5°C / min and keep it for 1 hour to remove the binder PVDF.

[0082] Step 4: Manually separate the positive electrode active material and the aluminum foil, and grind the positive electrode active material into powder.

[0083] Step 5: Take part of the positive electrode active material and place it in a tablet press. Set the tablet press pressure to 8T and keep it at this pressure for 2 minutes to obtain a disc with a thickness of 4 mm and a diameter of 1.5 cm.

[0084] Step 6: Place the wafer vertically in a quartz sleeve with an inner diameter of 1.7 cm, and place the quartz sleeve in a tube furnace.

[0085] 2. Electrolyte preparation:

[0086] Step 7: In a glove box, an electrolyte composite solvent is prepared by adding dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC) to the collected electrolyte in a volume ratio of 1:1:1.

[0087] Step 8: Add LiPF6, stir to dissolve, and prepare a 1.5 mol / L electrolyte solution.

[0088] 3. Lithium iron phosphate cathode regeneration

[0089] Step 9: Under argon protection, heat the tube furnace to 250°C.

[0090] Step 10, take 20 mL of electrolyte and place it in the atomizer, adjust the atomization rate to 4 mL / min, atomize the electrolyte into the tubular furnace, and keep it for 30 minutes.

[0091] Step 11: Increase the temperature of the tube furnace to 650°C at a heating rate of 5°C / min and maintain for 6 hours.

[0092] Step 12: After cooling, the regenerated lithium iron phosphate positive electrode material is obtained.

[0093] Example 3

[0094] The present embodiment provides a method for regenerating a lithium iron phosphate positive electrode material from a battery electrolyte, comprising the following steps:

[0095] 1. Pretreatment of lithium iron phosphate positive electrode:

[0096] Step 1: The used lithium iron phosphate battery was immersed in a 5wt% NaCl solution for 24 hours to release the residual power, and then placed in an 80°C forced air drying oven for 12 hours.

[0097] Step 2: Manually disassemble the battery in the glove box, collect the positive electrode, diaphragm, negative electrode, and collect the electrolyte of the used battery.

[0098] Step 3: Place the positive electrode sheet in a tubular furnace, and under argon protection, heat it to 400°C at a heating rate of 5°C / min and keep it for 1.5 hours to remove the binder PVDF.

[0099] Step 4: Manually separate the positive electrode active material and the aluminum foil, and grind the positive electrode active material into powder.

[0100] Step 5: Take part of the positive electrode active material and place it in a tablet press. Set the tablet press pressure to 8T and keep it at this pressure for 1 minute to obtain a disc with a thickness of 5 mm and a diameter of 1.5 cm.

[0101] Step 6: Place the wafer vertically in a quartz sleeve with an inner diameter of 1.7 cm, and place the quartz sleeve in a tube furnace.

[0102] 2. Electrolyte preparation:

[0103] Step 7: In a glove box, prepare an electrolyte composite solvent by adding dimethyl carbonate (DMC) and ethylene carbonate (EC) to the collected electrolyte in a volume ratio of 1:1.

[0104] Step 8: Add LiPF6, stir to dissolve, and prepare a 0.5 mol / L electrolyte solution.

[0105] 3. Lithium iron phosphate cathode regeneration

[0106] Step 9: Under argon protection, heat the tube furnace to 230°C.

[0107] Step 10: Take 10 mL of electrolyte and place it in the atomizer. Adjust the atomization rate to 5 mL / min, atomize the electrolyte into the tubular furnace, and keep it for 30 minutes.

[0108] Step 11: Increase the temperature of the tube furnace to 750°C at a heating rate of 5°C / min and maintain for 4 hours.

[0109] Step 12: After cooling, the regenerated lithium iron phosphate positive electrode material is obtained.

[0110] Example 4

[0111] The present embodiment provides a method for regenerating a lithium iron phosphate positive electrode material from a battery electrolyte, comprising the following steps:

[0112] 1. Pretreatment of lithium iron phosphate positive electrode:

[0113] Step 1: The used lithium iron phosphate battery was immersed in a 5wt% NaCl solution for 24 hours to release the residual power, and then placed in an 80°C forced air drying oven for 12 hours.

[0114] Step 2: manually disassemble the battery in a glove box with a nitrogen atmosphere, collect the positive electrode sheet, the diaphragm, the negative electrode sheet, and collect the electrolyte of the used battery.

[0115] Step 3: Place the positive electrode sheet in a tube furnace, and under argon protection, heat it to 500°C at a heating rate of 5°C / min and keep it for 2 hours to remove the binder PVDF.

[0116] Step 4: Manually separate the positive electrode active material and the aluminum foil, and grind the positive electrode active material into powder.

[0117] Step 5: Take a portion of the positive electrode active material and place it in a tablet press. Set the tablet press pressure to 8T and keep it at this pressure for 1 minute to obtain a disc with a thickness of 3 mm and a diameter of 1.5 cm.

[0118] Step 6: Place the wafer vertically in a quartz sleeve with an inner diameter of 1.7 cm, and place the quartz sleeve in a tube furnace.

[0119] 2. Electrolyte preparation:

[0120] Step 7: In a glove box, prepare an electrolyte composite solvent by adding dimethyl carbonate (DMC) and ethylene carbonate (EC) to the collected electrolyte in a volume ratio of 1:1.

[0121] Step 8: Add LiPF6, stir to dissolve, and prepare a 1.5 mol / L electrolyte solution.

[0122] 3. Lithium iron phosphate cathode regeneration

[0123] Step 9: Under argon protection, heat the tube furnace to 200°C.

[0124] Step 10, take 20 mL of electrolyte and place it in the atomizer, adjust the atomization rate to 3 mL / min, atomize the electrolyte into the tubular furnace, and keep it for 30 minutes.

[0125] Step 11: Raise the temperature of the tube furnace to 700°C at a heating rate of 5°C / min and maintain for 8 hours.

[0126] Step 12: After cooling, the regenerated lithium iron phosphate positive electrode material is obtained.

Claims

1. A method for regenerating lithium iron phosphate positive electrode material from battery electrolyte, characterized in that The steps include: 1) Pre-treating waste lithium iron phosphate batteries to obtain waste lithium iron phosphate positive electrode sheets and collecting waste battery electrolytes; 2) placing the waste lithium iron phosphate positive electrode sheet in a tube furnace and calcining it at high temperature in an inert atmosphere to remove the binder, separate the positive electrode active material from the aluminum foil, and grind the waste lithium iron phosphate positive electrode powder; 3) Pressing the positive electrode powder into lithium iron phosphate positive electrode sheets; 4) adding LiPF6 and a composite solvent to the electrolyte recovered in step 1) to prepare an electrolyte of standard concentration; 5) placing the lithium iron phosphate positive electrode sheet in a casing and placing it in a tube furnace, and raising the temperature of the tube furnace to a certain temperature under the protection of an inert atmosphere; 6) placing the electrolyte prepared in step 5) in an atomizer, and under the protection of an inert atmosphere, introducing the electrolyte into a tubular furnace through the atomizer to contact the lithium iron phosphate positive electrode sheet; 7) Raise the temperature in the tube furnace to 650-750°C at 5°C / min under inert atmosphere, and calcine the positive electrode material for 4-8h; 8) After calcination, the regenerated lithium iron phosphate positive electrode material is obtained by naturally cooling down.

2. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 1, characterized in that: During the pretreatment of the waste lithium iron phosphate battery in step 1), the waste battery is placed in a 5wt% NaCl solution for discharge, and then disassembled under the protection of an inert atmosphere to obtain a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte.

3. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 2, characterized in that: The disassembly process in step 1) is carried out in a glove box with a water concentration of less than 0.01 ppm and an oxygen concentration of less than 0.01 ppm.

4. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 1, characterized in that: In the step 2), the waste lithium iron phosphate positive electrode sheet is calcined at a high temperature of 400° C. to 600° C. for 1 to 2 hours to remove the binder on the surface and separate the positive electrode active material and the aluminum foil.

5. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 1, characterized in that: In the step 3), the positive electrode powder is pressed into a sheet with a thickness of 3 to 5 mm under a pressure of 8 T.

6. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 1, characterized in that: The electrolyte LiPF6 concentration configured in the step 4) is 0.5-1.5 mol / L, and the added composite solvent includes ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) in a volume ratio of 1:1:1 or dimethyl carbonate (DMC) and ethylene carbonate (EC) in a volume ratio of 1:

1.

7. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 1, characterized in that: In the step 5), the temperature of the tube furnace is increased to 200-250°C.

8. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 7, characterized in that: The atomization rate of the electrolyte in step 6) is 3-5 mL / min.

9. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 7, characterized in that: The inert atmosphere used in steps 2), 6), 7) and 8) is provided by N2 or Ar.

10. The method for regenerating lithium iron phosphate positive electrode material from battery electrolyte according to claim 7, characterized in that: In the step 5), the lithium iron phosphate positive electrode sheet is placed vertically in a sleeve and placed in a tubular furnace.

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