WO2024229788A1 - Method for repairing and regenerating positive electrode material by recovering waste battery in full-chain integrated manner - Google Patents

Abstract

The present disclosure provides a method for repairing and regenerating a positive electrode material by recovering a waste battery in a full-chain integrated manner. The repairing and regenerating method comprises the following steps: (1) discharging a waste battery, and then performing pyrolysis and separation thereon to obtain a positive electrode material powder; (2) performing a lithium-supplementing calcination treatment on the positive electrode material powder, and performing condensation recovery, acid-gas removal and organic-gas collection treatments on the waste gas; and (3) mixing the collected organic gas and silicon tetrafluoride to obtain a mixed gas, performing a plasma coating treatment on the powder, which is obtained by lithium-supplementing calcination, by using the mixed gas so as to obtain a silicon-carbide-coated positive electrode material, recovering the obtained waste gas by using SiO₂, and drying the obtained silicon tetrafluoride gas for cyclic utilization. The present disclosure not only utilizes the organic gas generated by the decomposition of the electrolytic solution, but also restores the performance of a lithium iron phosphate positive electrode material; and the whole reaction process only consumes silica while fixing tail gas, and the reagent consumption and the cost are low.

Description

A method for recycling waste batteries and repairing and regenerating positive electrode materials in a full-chain integrated manner Technical Field

The present invention belongs to the field of resource recycling technology, for example, a method for recycling waste batteries and repairing and regenerating positive electrode materials in an integrated whole-chain manner.

Background Art

With the rapid development of the new energy vehicle industry, lithium iron phosphate batteries have stood out among lithium-ion power batteries due to their advantages such as good thermal stability, high safety performance and excellent cycle stability. However, the life of power batteries is limited, and the number of retired lithium iron phosphate power batteries is increasing year by year. If they cannot be effectively utilized, it will cause waste of resources and environmental pollution. "Full-chain integrated recycling" as the main means of circular economy can effectively solve the above problems.

The valuable components of lithium iron phosphate batteries are mainly present in the positive electrode materials, so the full-chain integrated recycling of lithium iron phosphate batteries is mainly to recycle and reuse waste lithium iron phosphate positive electrode materials. The commonly used recycling methods for lithium iron phosphate positive electrode materials are pyrometallurgical recycling and wet recycling. Both methods separate and extract valuable metals from waste positive electrode materials, which are energy-intensive and require a large amount of acid and alkali reagents, and the overall recycling cost is high. Since the price of lithium iron phosphate is relatively low compared to ternary positive electrode materials and the valuable metal content is low, the economic benefits of recycling using traditional methods are not high.

CN114006070A discloses a method for high-temperature pyrolysis and pneumatic stripping and sorting of waste lithium batteries. The waste gas generated by pyrolysis is treated by high-temperature incineration, rapid cooling, water washing, alkali washing and other processes before being discharged in compliance with emission standards. This method not only consumes energy, but also causes a large amount of carbon dioxide emissions, which is not conducive to the realization of the dual carbon goals.

CN115312903A discloses a method for regenerating waste lithium iron phosphate to prepare rate-type lithium iron phosphate, comprising adding water to waste lithium iron phosphate powder and ferrous disulfide in a molar ratio to prepare a slurry and mixing; Lithium powder and hydrogen ions are added to the acid solution in molar ratio, and water is added according to the solid-liquid ratio to adjust the slurry and stir; the mixed slurry is transferred to an autoclave, sealed and introduced with oxidizing gas, heated and stirred for reaction, and then kept warm; the filtrate after the reaction is filtered, phosphorus source and lithium source are added to the filtrate, and the temperature is increased and kept warm after adding a dispersant; the slurry is filtered and washed after insulation and cooling, and sprayed to obtain a spray material; the spray material is sintered under a protective atmosphere to obtain a carbon-coated lithium iron phosphate positive electrode material. The regeneration method can replenish lithium for waste positive electrode materials, restore the material morphology, composition and electrochemical properties, and realize the regeneration of positive electrode materials. The entire regeneration process consumes less reagents, has a short process and low environmental pollution. However, the performance of the regenerated positive electrode material is not very ideal. This is because, although the waste positive electrode material has been replenished with lithium, the positive electrode material has poor conductivity, and the outer carbon coating layer has defects during the cycle. It is difficult to completely restore or improve the conductivity of the positive electrode material by only replenishing lithium, so the electrochemical performance of the regenerated positive electrode material is not ideal.

In addition to the cathode material, the electrolyte is also one of the main components of waste lithium-ion batteries. During the pyrolysis of battery fragments, the electrolyte decomposes and produces a large amount of organic gas. Currently, the direct combustion of organic gas is generally used for treatment.

Summary of the invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The purpose of the present invention is to provide a method for recycling waste batteries and repairing and regenerating positive electrode materials in an integrated manner. The present invention not only utilizes the organic gas generated by the decomposition of the electrolyte, but also restores the performance of the lithium iron phosphate positive electrode material. The entire reaction process only consumes silicon dioxide while fixing the tail gas, with low reagent consumption and low cost.

In order to achieve the purpose of this disclosure, the present disclosure adopts the following technical solutions:

In a first aspect, the embodiments of the present disclosure provide a method for recycling waste batteries and repairing and regenerating positive electrode materials in an integrated manner, wherein the repair and regeneration method comprises the following steps:

(1) discharging the waste batteries and performing pyrolysis separation to obtain positive electrode material powder;

(2) performing lithium supplementation calcination treatment on the positive electrode material powder;

(3) Mixing an organic gas and silicon tetrafluoride to obtain a mixed gas, using the mixed gas to perform plasma coating treatment on the powder obtained by lithium supplementation calcination to obtain a silicon carbide coated positive electrode material, recovering the obtained waste gas using _SiO2 , and drying the obtained silicon tetrafluoride gas for recycling.

After the waste battery described in the embodiment of the present disclosure is discharged, it is disassembled and crushed to obtain pre-treated battery fragments, and the battery fragments are pyrolyzed to obtain waste positive electrode material powder and waste gas.

In the repair and regeneration method described in the embodiment of the present disclosure, the carbon capture flow can fix carbon in the coating layer of the regenerated lithium iron phosphate, and will not produce carbon dioxide emissions, which is beneficial to reducing carbon emissions. The fluorine circulation flow can realize the recycling of HF, and does not require further collection and treatment of harmful gases, which is beneficial to reducing environmental pollution. The regenerated silicon carbide-coated lithium iron phosphate can repair the damage of the carbon coating layer of the waste lithium iron phosphate, and the coating surface is smoother, and the material has excellent electrochemical properties. The entire reaction process only consumes silicon dioxide while fixing the exhaust gas, with low reagent consumption and low cost.

The reaction equation for recycling the waste gas using SiO ₂ in the embodiment of the present disclosure is: SiO ₂ +4HF=SiF ₄ +2H ₂ O.

In one embodiment, the waste batteries in step (1) include any one of waste lithium iron phosphate batteries, waste lithium cobalt oxide batteries or waste ternary batteries, or a combination of at least two of them.

In one embodiment, the temperature of the pyrolysis treatment in step (1) is 400-600°C, for example, 400°C, 450°C, 500°C, 550°C or 600°C.

In one embodiment, the pyrolysis treatment time is 3 to 8 hours, for example: 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours.

In one embodiment, the lithium supplementation calcination treatment in step (2) includes testing the lithium deficiency of the positive electrode material powder by inductively coupled plasma mass spectrometry (ICP testing), determining the amount of lithium source added, and adding the positive electrode material to the positive electrode material. The material powder is mixed with the lithium source, ball-milled and then calcined.

In one embodiment, when the positive electrode material powder is lithium iron phosphate, a reducing agent is added.

In one embodiment, the reducing agent includes any one of sucrose, glucose, cellulose or elemental carbon, or a combination of at least two thereof.

In one embodiment, the amount of the reducing agent added is 1-5% of the mass of the positive electrode material powder, for example: 1%, 2%, 3%, 4% or 5%, etc. Preferably, it is 2-3%.

In one embodiment, the lithium source includes any one of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxalate, lithium acetate, lithium dihydrogen phosphate, or lithium hydrogen phosphate, or a combination of at least two thereof.

In one embodiment, the ball milling time is 0.5 to 2 h, for example, 0.5 h, 0.8 h, 1 h, 1.5 h or 2 h.

In one embodiment, the calcination temperature is 650-800°C, for example, 650°C, 680°C, 700°C, 750°C or 800°C.

In one embodiment, the calcination time is 1 to 5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours or 5 hours.

In one embodiment, the calcination atmosphere is nitrogen and/or argon.

In one embodiment, the organic gas in step (3) is obtained by condensing and recovering the waste gas obtained by the pyrolysis in step (1), and collecting it after removing the acidic gas.

In one embodiment, the organic gas includes any one of C ₂ H ₄ , CH ₄ or C ₂ H ₆ or a combination of at least two thereof.

In one embodiment, the volume ratio of the organic gas to silicon tetrafluoride in step (3) is 1:(1-5), for example: 1:1, 1:2, 1:3, 1:4 or 1:5, etc.

In one embodiment, the flow rate of the mixed gas in step (3) is 50 to 100 mL/min, for example, 50 mL/min, 60 mL/min, 70 mL/min, 80 mL/min, 90 mL/min or 100 mL/min.

In one embodiment, the electron energy of the plasma coating treatment is 20-30 eV, for example, 20 eV, 22 eV, 25 eV, 38 eV or 30 eV.

In one embodiment, the temperature of the plasma coating treatment is 350-500° C., for example, 350° C., 380° C., 400° C., 450° C. or 500° C.

In one embodiment, the waste gas obtained by the plasma coating treatment is recovered using _SiO2 , and the obtained silicon tetrafluoride gas is dried and recycled.

In one embodiment, based on the mass of the silicon carbide coated positive electrode material being 100%, the mass fraction of the silicon carbide coating layer is 0.1-2%, for example: 0.1%, 0.5%, 0.8%, 1%, 1.5% or 2%.

As an optional solution of the present disclosure, the repair and regeneration method comprises the following steps:

(1) discharging the waste battery and performing pyrolysis treatment to obtain waste gas and positive electrode material powder;

(2) testing the lithium deficiency of the positive electrode material powder by ICP, determining the amount of lithium source added, mixing the positive electrode material powder, the lithium source and the reducing agent, calcining at 650-800° C. for 1-5 hours, wherein the amount of the reducing agent added is 1-5% of the mass of the positive electrode material powder, and condensing and recovering the waste gas, removing acidic gas and collecting organic gas for treatment;

(3) The organic gas collected in step (2) and silicon tetrafluoride are mixed in a volume ratio of 1:(1-5) to obtain a mixed gas, and the mixed gas is introduced into a plasma reactor at a flow rate of 50-100 mL/min. The powder obtained by lithium supplementation calcination is subjected to plasma coating treatment under the conditions of an electron energy of 20-30 eV and a constant temperature zone temperature of 350-500° C. to obtain a silicon carbide coated positive electrode material, and the obtained waste gas is recovered using _SiO2 , and the obtained silicon tetrafluoride gas is dried and recycled.

Compared with the prior art, the present invention has the following beneficial effects:

(1) In the repair and regeneration method disclosed in the present invention, the carbon capture flow can fix carbon in the coating layer of the regenerated lithium iron phosphate, and will not generate carbon dioxide emissions, which is beneficial to reducing carbon emissions. The fluorine circulation flow can realize the recycling of HF, and does not require further collection and treatment of harmful gases, which is beneficial to reducing environmental pollution. The regenerated silicon carbide coated lithium iron phosphate can repair the damage of the carbon coating of the waste lithium iron phosphate, and the coated surface is smoother. The material has excellent electrochemical properties. The entire reaction process only consumes silicon dioxide while fixing the exhaust gas, with low reagent consumption and low cost.

(2) The lithium iron phosphate battery regenerated by the method disclosed in the present invention has a 0.1C gram capacity of more than 152.79 mAh/g, a coulombic efficiency of more than 96.41%, a 1C gram capacity of more than 138.09 mAh/g, and a compaction density of more than 2.511 g/ ^cm3 .

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

FIG1 is a schematic diagram of the process flow of the repair and regeneration method described in Example 1 of the present disclosure.

FIG. 2 is an XRD diagram of the silicon carbide coated positive electrode material obtained in Example 1 of the present disclosure.

DETAILED DESCRIPTION

The technical solution of the present disclosure is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only to help understand the present disclosure and should not be regarded as specific limitations of the present disclosure.

Example 1

This embodiment provides a method for repairing and regenerating a positive electrode material of a battery, and the method comprises the following steps:

(1) discharging, disassembling and crushing the retired power batteries, subjecting the obtained battery fragments to pyrolysis treatment at 600° C. for 4 h, subjecting the waste gas after pyrolysis to step (2), and collecting the waste lithium iron phosphate positive electrode powder;

(2) Determine the Fe/Li ratio of waste lithium iron phosphate by ICP test, mix lithium source and reducing agent into waste lithium iron phosphate positive electrode material, and ball mill for 1 hour in a ball mill to make Fe/Li=1:1.05, the lithium source is lithium hydroxide, the reducing agent is sucrose, and the amount of reducing agent added is 3% of the mass of waste lithium iron phosphate powder. The mixed waste lithium iron phosphate powder is placed in a nitrogen atmosphere and calcined at 750℃ for 3 hours, and the electrolyte waste gas is condensed and recovered, the acid gas is removed, and _the organic gas (main components are _C2H4 , _CH4 , _{C2H6 ,} etc.) is collected in turn;

(3) Mix the organic gas with the silicon fluoride gas under normal pressure, control the gas flow rate to 60 mL/min, and the volume ratio of the organic gas to the silicon fluoride is 1:2. Evenly spread the powder obtained by calcining the lithium supplement on a porcelain boat, place the porcelain boat in the constant temperature zone of the reactor, and then pass the mixed gas into the plasma reactor. Set the electron energy generated by the plasma reactor to 25 eV, adjust the temperature of the constant temperature zone to 400 ° C, react for 2 hours, and obtain silicon carbide-coated lithium iron phosphate (silicon carbide mass fraction is 1%). The XRD diagram of the silicon carbide-coated lithium iron phosphate is shown in Figure 2. Collect the waste gas and recycle it using SiO _2. The reaction equation is as follows: SiO ₂ +4HF＝SiF ₄ +2H ₂ O. The obtained silicon tetrafluoride gas is dried and reused.

Example 2

This embodiment provides a method for repairing and regenerating a positive electrode material of a battery, and the method comprises the following steps:

(1) discharging, disassembling and crushing the retired power batteries, subjecting the obtained battery fragments to pyrolysis treatment at 620° C. for 4 h, subjecting the waste gas after pyrolysis to step (2), and collecting the waste lithium iron phosphate positive electrode powder;

(2) The Fe/Li ratio of the waste lithium iron phosphate was determined by ICP testing. A lithium source and a reducing agent were mixed into the waste lithium iron phosphate positive electrode material, and the mixture was ball-milled in a ball mill for 1 hour to make Fe/Li = 1:1.02. The lithium source was lithium hydroxide, and the reducing agent was sucrose. The amount of reducing agent added was 3.2% of the mass of the waste lithium iron phosphate powder. The waste lithium iron phosphate powder after uniform mixing is placed in a nitrogen atmosphere and calcined at 780°C for 2.5 hours. The electrolyte waste gas is condensed and recovered, the acid gas is removed, and the organic gas (main components are C ₂ H ₄ , CH ₄ , C ₂ H _6, etc.) is collected in turn;

(3) Mix the organic gas with the silicon fluoride gas under normal pressure, control the gas flow rate to 70 mL/min, and the volume ratio of the organic gas to the silicon fluoride to be 1:3. Evenly spread the powder obtained by calcining the lithium supplement on a porcelain boat, place the porcelain boat in the constant temperature zone of the reactor, and then pass the mixed gas into the plasma reactor. Set the electron energy generated by the plasma reactor to 27 eV, adjust the temperature of the constant temperature zone to 380 ° C, react for 2 hours, and obtain silicon carbide-coated lithium iron phosphate (silicon carbide mass fraction is 1.1%). Collect the waste gas and recycle it using SiO _2. The reaction equation is as follows: SiO ₂ +4HF＝SiF ₄ +2H ₂ O. The obtained silicon tetrafluoride gas is dried and reused.

Example 3

The only difference between this embodiment and embodiment 1 is that the amount of reducing agent added is 1% of the mass of the waste lithium iron phosphate powder, and the other conditions and parameters are exactly the same as those in embodiment 1.

Example 4

The only difference between this embodiment and embodiment 1 is that the amount of reducing agent added is 5% of the mass of the waste lithium iron phosphate powder, and the other conditions and parameters are exactly the same as those in embodiment 1.

Example 5

The only difference between this embodiment and embodiment 1 is that the electron energy in step (3) is 15 eV, and the other conditions and parameters are exactly the same as those in embodiment 1.

Example 6

The only difference between this embodiment and embodiment 1 is that the electron energy in step (3) is 35 eV, and the other conditions and parameters are exactly the same as those in embodiment 1.

Example 7

The only difference between this embodiment and embodiment 1 is that the volume ratio of the organic gas to silicon fluoride in step (3) is 2:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

Example 8

The only difference between this embodiment and embodiment 1 is that the volume ratio of the organic gas to silicon fluoride in step (3) is 1:10, and the other conditions and parameters are exactly the same as those in embodiment 1.

Comparative Example 1

This comparative example provides a method for repairing and regenerating a positive electrode material of a battery, and the repairing and regenerating method comprises the following steps:

S1: Discharge, dismantle and crush retired power batteries;

S2: Pyrolysis treatment is performed on the battery fragments pre-treated by S1, and the waste gas after pyrolysis is condensed and recovered to collect the waste lithium iron phosphate positive electrode powder;

S3: Determine the Fe/Li ratio of waste lithium iron phosphate by ICP test, mix lithium source and reducing agent into waste lithium iron phosphate positive electrode material, and ball mill for 1h in a ball mill to make Fe/Li=1:1.05, the lithium source is lithium hydroxide, the reducing agent is sucrose, and the amount of reducing agent added is 10% of the mass of waste lithium iron phosphate powder. Place the mixed waste lithium iron phosphate powder in a nitrogen atmosphere and calcine at 750℃ for 3h. Obtain repaired and regenerated carbon-coated lithium iron phosphate.

Comparative Example 2

This comparative example directly uses silicon carbide solid phase coating of commercial lithium iron phosphate positive electrode material.

Performance Test:

The lithium iron phosphate prepared in the embodiment and the comparative example, the conductive agent acetylene black, and the binder PVDF were mixed in a mass ratio of 90:5:5, and an appropriate amount of N-methyl pyrrolidone was added to coat the slurry. On an aluminum foil, dry at 120°C for 12 hours in a vacuum dryer to form a positive electrode sheet; assemble a half-cell with a metal lithium sheet as the negative electrode, and test the electrochemical performance. The test results are shown in Table 1:

Table 1

As can be seen from Table 1, from Examples 1-2, the lithium iron phosphate battery regenerated by the method described in the present invention has a 0.1C gram capacity of more than 152.79 mAh/g, a coulombic efficiency of more than 96.41%, a 1C gram capacity of more than 138.09 mAh/g, and a compaction density of more than 2.511 g/ ^cm3 .

By comparing Example 1 with Examples 3-4, it can be seen that in the repair and regeneration method disclosed in the present invention, the amount of the reducing agent added will affect the effect of preparing the silicon carbide coated positive electrode material. The effect of preparing the silicon carbide coated positive electrode material is better when the amount of the reducing agent added is controlled to 2-3% of the mass of the positive electrode material powder. If the amount of raw agent added is too large, the carbon coating of the regenerated lithium iron phosphate will be too thick, which will reduce its capacity. If the amount of reducing agent added is too low, the valence state of the iron element in the waste lithium iron phosphate cannot be completely reduced, and it is difficult to initially repair the defective carbon coating, resulting in the electrochemical performance and cycle stability of the repaired lithium iron phosphate being difficult to meet commercial needs.

By comparing Example 1 with Examples 5-6, it can be seen that in the repair and regeneration method disclosed in the present invention, the electron energy of the plasma coating treatment will affect the effect of obtaining the silicon carbide coated positive electrode material. The electron energy of the plasma coating treatment is controlled at 20-30 eV, and the effect of obtaining the silicon carbide coated positive electrode material is better. If the electron energy is too large, although the reaction is promoted, the reaction proceeds rapidly and non-specific reactions may occur, reducing the gram capacity and rate performance, and slightly reducing the coulombic efficiency. If the electron energy is too small and the proportion of organic gas is too small, the reaction rate is slow and the product selectivity is affected, the overall electrochemical performance is reduced, and it cannot be ensured that the reaction can occur or the reaction rate is slow.

By comparing Example 1 with Examples 7-8, it can be seen that in the repair and regeneration method disclosed in the present invention, the volume ratio of organic gas to silicon fluoride will affect the effect of preparing the silicon carbide coated positive electrode material. When the volume ratio of organic gas to silicon fluoride is controlled between 1:1 and 1:5, the effect of preparing the silicon carbide coated positive electrode material is better. If the proportion of organic gas is too large, although it promotes the occurrence of the reaction, it will produce a thicker carbon coating layer and reduce the gram capacity of the repair material. If the proportion of organic gas is too small, the reaction rate is slow and the product selectivity is affected.

From the comparison between Example 1 and Comparative Example 1, it can be seen that the use of silicon carbide to coat the regenerated lithium iron phosphate can repair the defects of the surface coating layer of the waste lithium iron phosphate, which is beneficial to the recovery of its electrochemical performance.

By comparing Example 1 with Comparative Example 2, it can be seen that the silicon carbide coated positive electrode material recovered by the repair method of the present disclosure has a similar effect to the silicon carbide coated positive electrode material prepared from commercial lithium iron phosphate, indicating that the repair and recovery method of the present application has a better recovery effect, and the carbon capture flow can fix carbon in the coating layer of the regenerated lithium iron phosphate, and will not generate carbon dioxide emissions, which is beneficial to reducing carbon emissions. The fluorine circulation flow can achieve The current recycling of HF does not require further collection and treatment of harmful gases, which is beneficial to reducing environmental pollution.

Claims (16)

A method for recycling waste batteries and repairing and regenerating positive electrode materials in an integrated manner, the repair and regeneration method comprising the following steps: (1) discharging the waste batteries and performing pyrolysis separation to obtain positive electrode material powder; (2) performing lithium supplementation calcination treatment on the positive electrode material powder; (3) An organic gas and silicon tetrafluoride are mixed to obtain a mixed gas, and the mixed gas is used to perform plasma coating treatment on the powder obtained by lithium supplementation calcination to obtain a silicon carbide coated positive electrode material. The repair and regeneration method as claimed in claim 1, wherein the waste battery in step (1) comprises any one of waste lithium iron phosphate batteries, waste lithium cobalt oxide batteries or waste ternary batteries, or a combination of at least two of them. The repair and regeneration method according to claim 1 or 2, wherein the temperature of the pyrolysis treatment in step (1) is 400 to 600°C; Optionally, the pyrolysis treatment time is 3 to 8 hours. The repair and regeneration method according to any one of claims 1 to 3, wherein the lithium supplementation calcination treatment in step (2) includes testing the lithium deficiency amount of the positive electrode material powder by an inductively coupled plasma mass spectrometer, determining the amount of lithium source added, mixing the positive electrode material powder and the lithium source, and calcining after ball milling. The repair and regeneration method according to claim 4, wherein when the positive electrode material powder is lithium iron phosphate, a reducing agent is added; Optionally, the reducing agent includes any one of sucrose, glucose, cellulose or elemental carbon, or a combination of at least two thereof; Optionally, the amount of the reducing agent added is 1 to 5% of the mass of the positive electrode material powder. The repair and regeneration method according to claim 5, wherein the amount of the reducing agent added is 2 to 3% of the mass of the positive electrode material powder. The repair and regeneration method according to any one of claims 4 to 6, wherein the lithium source comprises hydrogen and oxygen Any one of lithium chloride, lithium carbonate, lithium nitrate, lithium oxalate, lithium acetate, lithium dihydrogen phosphate or lithium hydrogen phosphate, or a combination of at least two thereof. The repair and regeneration method according to any one of claims 4 to 7, wherein the ball milling time is 0.5 to 2 hours. The repair and regeneration method according to any one of claims 4 to 8, wherein the calcination temperature is 650 to 800° C. Optionally, the calcination time is 1 to 5 hours. The repair and regeneration method according to any one of claims 4 to 9, wherein the calcination atmosphere is nitrogen and/or argon. The repair and regeneration method according to any one of claims 1 to 10, wherein the organic gas in step (3) is obtained by condensing and recovering the waste gas obtained by pyrolysis in step (1), and collecting it after removing the acidic gas; Optionally, the organic gas includes any one of C ₂ H ₄ , CH ₄ or C ₂ H ₆ or a combination of at least two thereof. The repair and regeneration method according to any one of claims 1 to 11, wherein the volume ratio of the organic gas to silicon tetrafluoride in step (3) is 1:(1 to 5). The repair and regeneration method according to any one of claims 1 to 12, wherein the flow rate of the mixed gas in step (3) is 50 to 100 mL/min. The repair and regeneration method according to any one of claims 1 to 13, wherein the electron energy of the plasma coating treatment in step (3) is 20 to 30 eV; Optionally, the temperature of the plasma coating treatment is 350-500° C.; Optionally, the waste gas obtained by the plasma coating treatment is recovered using _SiO2 , and the obtained silicon tetrafluoride gas is dried and recycled. The repair and regeneration method according to any one of claims 1 to 14, wherein the mass fraction of the silicon carbide coating layer is 0.1 to 2%, based on the mass of the silicon carbide coated positive electrode material being 100%. The repair and regeneration method according to any one of claims 1 to 15, wherein the repair and regeneration method comprises the following steps: (1) discharging the waste battery and performing pyrolysis treatment to obtain waste gas and positive electrode material powder; (2) testing the lithium deficiency of the positive electrode material powder by ICP, determining the amount of lithium source added, mixing the positive electrode material powder, the lithium source and the reducing agent, calcining at 650-800° C. for 1-5 hours, wherein the amount of the reducing agent added is 1-5% of the mass of the positive electrode material powder, and condensing and recovering the waste gas, removing acidic gas and collecting organic gas for treatment; (3) The organic gas collected in step (2) and silicon tetrafluoride are mixed in a volume ratio of 1:(1-5) to obtain a mixed gas, and the mixed gas is introduced into a plasma reactor at a flow rate of 50-100 mL/min. The powder obtained by lithium supplementation calcination is subjected to plasma coating treatment for 1-5 hours under the conditions of an electron energy of 20-30 eV and a constant temperature zone temperature of 350-500° C. to obtain a silicon carbide coated positive electrode material, and the obtained waste gas is recovered using _SiO2 , and the obtained silicon tetrafluoride gas is dried and recycled.