Method and system for continuously separating binder from lithium iron phosphate pole piece powder based on scCO2

Abstract

The invention discloses a method and a system for continuously separating a binder from lithium iron phosphate pole piece powder based on scCO2. The method comprises the following steps: crushing and pretreating a pole piece, then feeding the pole piece into a supercritical carbon dioxide extraction kettle, pre-extracting under a low-pressure condition, and then boosting to carry out enhanced extraction, so that a binder is desorbed from the surface of lithium iron phosphate and is dissolved into supercritical carbon dioxide; the fluid carrying the binder is guided into a serial cyclone separator group, solid-gas separation is realized through graded pressure reduction, an anti-flocculation solution is added at a solid phase outlet, and SBR and PVDF are recovered respectively; and the separated carbon dioxide is recycled after being condensed and compressed. According to the method, the binder in the pole piece powder is efficiently removed and recycled under the low-temperature condition, no organic solvent is needed, energy consumption is low, environment friendliness is achieved, the lithium iron phosphate recycling rate is high, and the obtained regenerated material is excellent in electrochemical performance and suitable for large-scale application.

Description

Technical Field

[0001] This invention relates to the field of lithium battery recycling technology, and in particular to a method and system for continuous separation of binders in lithium iron phosphate electrode powder based on scCO2. Background Technology

[0002] With the widespread application of lithium-ion batteries in new energy vehicles and energy storage, a large amount of lithium iron phosphate battery electrode powder generated during retirement and production processes urgently needs to be recycled and reused at high value. Electrode powder is usually composed of lithium iron phosphate active material, conductive agent (such as carbon black), and binder (such as polyvinylidene fluoride PVDF, styrene-butadiene rubber SBR in aqueous systems, etc.). The binder plays a role in structural fixation in the electrode, but it can seriously affect the dispersibility, compaction density, and electrochemical performance of the powder during recycling and regeneration. Therefore, it needs to be effectively removed without destroying the structure of the active material.

[0003] In existing technologies, a relatively mature method involves dissolving and recovering the binder in electrode powder using organic solvents, typically including N-methylpyrrolidone (NMP). However, this type of method usually requires prolonged extraction at high temperatures and solvent recovery via distillation, resulting in high overall energy consumption. The energy consumption for processing a unit of electrode powder often exceeds 2000 kWh / ton, which is not conducive to large-scale and low-carbon applications. In addition, high-boiling-point organic solvents such as NMP are prone to incomplete recovery, easily leaving residues in the regenerated powder. The residue levels can exceed 500 ppm, posing not only environmental and health hazards but also adversely affecting the electrochemical stability and safety of the regenerated lithium iron phosphate materials.

[0004] Another common method is mechanical separation, such as crushing, sieving, or air classification, which attempts to separate the binder from the active material through physical means. However, since the binder is usually tightly bound to the surface of lithium iron phosphate particles and conductive agents in the form of coating or bridging, simple mechanical action is difficult to achieve selective removal. This often leads to incomplete separation of lithium iron phosphate and carbon black, and may even introduce particle breakage and surface defects. As a result, the specific capacity, rate performance, and other electrochemical properties of the regenerated powder decrease, with performance degradation exceeding 20%, making it difficult to meet the material performance requirements of power or energy storage batteries.

[0005] Therefore, existing technologies generally suffer from problems such as high energy consumption, high risk of solvent residue, or unsatisfactory separation effect. There is an urgent need to develop a new method for removing binders from lithium iron phosphate electrode powder that can operate at lower temperatures, has high removal efficiency, and has little impact on the structure of active materials, so as to achieve green, efficient and high-quality recycling and regeneration. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a method for continuous separation of binders in lithium iron phosphate electrode powder based on scCO2. By utilizing the green, non-toxic, and easily desolvable properties of scCO2, the binder can be removed at low temperature and efficiently, and high-purity binder can be recovered for regeneration and reuse.

[0007] The technical solution of the present invention: To achieve the above objectives, the present invention provides a method and system for continuous separation of binders in lithium iron phosphate electrode powder based on scCO2, the method comprising the following steps: S1. Pretreatment: The electrode sheets are crushed and pretreated; S2.scCO2 extraction: The pretreated electrode is fed into a supercritical CO2 extraction vessel and extracted and separated under low pressure; the pressure is increased and then extracted and separated under high pressure, so that the binder dissolves into scCO2 and falls off from the aluminum foil current collector; S3. Series hydrocyclone separation: The scCO2 carrying the binder flows out of the extraction vessel and into the series hydrocyclone separator group. After depressurization, the hydrocyclone separator performs solid-gas separation, and an anti-flocculation solution is added to the solid product by a micro metering pump. S4. Binder Collection: The solid product enters a collection tank to obtain the recovered binder; S5.scCO2 circulation: The separated scCO2 is condensed, compressed, and then circulated back to the extraction vessel.

[0008] Supercritical CO2 is a liquid that can extract different binders under different pressures. The binder is incorporated into the supercritical CO2 liquid and then flows out and vaporizes, completing the debinding of lithium iron phosphate and graphite anodes, while simultaneously regenerating the binder.

[0009] In some embodiments, the size of the pretreated electrode is 140-160 μm.

[0010] In some embodiments, the pretreated electrode is fed into the supercritical CO2 extraction vessel at a packing density of 0.7-0.9 g / cm³.

[0011] In some embodiments, the supercritical CO2 extraction vessel is set to a flow rate of 40-60 L / h and a pressurization rate of 5 MPa / min.

[0012] In some embodiments, the low-pressure extraction and separation pressure range is 10-15 MPa, the extraction temperature is 40-50°C, and the extraction time is 10-60 min.

[0013] In some embodiments, the high-pressure extraction and separation pressure range is 25-35 MPa, the extraction temperature is 50-60℃, and the extraction time is 10-60 min.

[0014] In some embodiments, the antiflocculation solution is an aqueous solution or an ethanol-water solution containing 0.1-0.5 wt% of an antiflocculating agent; the antiflocculating agent is selected from one or more combinations of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium stearate, and sodium fatty acid methyl ester sulfonate.

[0015] In some embodiments, the cyclone separator rotates at 3000-6000 rpm and the separation time is 5-10 min.

[0016] In a second aspect, the present invention provides a system for the method of continuous separation of binder in lithium iron phosphate electrode powder based on scCO2, the system comprising a pretreatment unit, an scCO2 extraction unit, a series-connected cyclone separation unit, a binder collection unit, and an scCO2 circulation unit connected in sequence. The pretreatment unit is used to crush and sieve the lithium iron phosphate electrode sheets; The scCO2 extraction unit includes an scCO2 extraction vessel, which is used to contact the electrode powder with scCO2 and remove the binder under adjustable temperature and pressure conditions; The series-connected cyclone separation unit is located at the outlet of the extraction vessel and is used to depressurize the scCO2 fluid carrying the binder and achieve solid-gas separation. The adhesive collection unit is connected to a series-connected cyclone separation unit for collecting different types of adhesives respectively. The scCO2 circulation unit is connected to the gas phase outlet and extraction vessel inlet of the series-connected cyclone separator unit, and is used to realize the condensation, compression and reuse of scCO2.

[0017] In some embodiments, the scCO2 extraction unit further includes a carbon dioxide storage tank, a high-pressure delivery pump, a heat exchanger, and a temperature and pressure control module; the carbon dioxide storage tank is connected to the air inlet of the extraction vessel via the high-pressure delivery pump, and the heat exchanger is located between the high-pressure delivery pump and the extraction vessel to adjust the carbon dioxide to a supercritical state.

[0018] In some embodiments, the series-connected cyclone separator group is provided with a solid phase outlet, and the solid phase outlets of different cyclone separators are respectively connected to the SBR collection tank and the PVDF collection tank.

[0019] In some embodiments, at least one solid phase outlet pipe of the series cyclone separation unit is provided with an antiflocculation agent addition unit, which includes an antiflocculation agent storage tank, a metering pump and a mixer, for continuously adding antiflocculation solution to the separated solid phase binder.

[0020] Furthermore, the mixer is positioned between the solid phase outlet of the cyclone separator and the binder collection tank.

[0021] In some embodiments, the scCO2 circulation unit includes a condenser, a gas-liquid separator, and a compressor connected in sequence, with the gas phase outlet of the gas-liquid separator connected to the compressor and the compressor outlet connected to the extraction vessel inlet.

[0022] In some embodiments, a continuous feeding device is provided between the pretreatment unit and the extraction vessel to achieve continuous feeding of electrode powder under high pressure conditions.

[0023] In some embodiments, the extraction vessel is equipped with a porous material-supporting basket or a fixed bed structure to enhance the contact efficiency between supercritical carbon dioxide and electrode powder.

[0024] In some embodiments, the hydrocyclone separator incorporates a ceramic membrane with a pore size of 0.1 μm.

[0025] In some embodiments, the cyclone separator may also be equipped with an electrostatic adsorption module. The voltage of the electrostatic adsorption module is ±5 kV, which can capture escaped nano-carbon black, ensure the purity of the regenerated powder, and help to regenerate the binder. Beneficial effects

[0026] Compared with existing organic solvent extraction or mechanical separation processes, the method and system for continuous separation of binders in lithium iron phosphate electrode powder based on supercritical carbon dioxide provided by this invention have significant advantages such as being green and efficient, having low energy consumption, high recovery rate, and excellent performance of recycled materials.

[0027] This invention uses supercritical carbon dioxide as the extraction medium and does not use toxic organic solvents such as NMP throughout the entire process. The carbon dioxide is recycled after condensation and compression, with virtually no emissions. This avoids the problems of highly toxic solvent residues and secondary pollution that exist in traditional processes, and has good environmental friendliness and safety.

[0028] By combining staged pressurized extraction with a series hydrocyclone separator, highly efficient removal and separation of binders from electrode powder is achieved, with binder recovery exceeding 95% and lithium iron phosphate powder recovery exceeding 99%, significantly reducing the loss of active materials. Simultaneously, the separation process is completed at near-room temperature, and the energy consumption per unit electrode powder processed can be controlled below 300 kWh / ton, significantly lower than the energy consumption level of over 2000 kWh / ton for traditional organic solvent methods, demonstrating significant economic advantages.

[0029] By avoiding the damage to the material structure caused by high temperatures and strong solvents, the regenerated lithium iron phosphate powder maintains good crystal integrity and electrochemical activity. Lithium-ion batteries prepared using the lithium iron phosphate powder recovered according to this invention can achieve an initial efficiency exceeding 92%, and a capacity retention rate of over 85% after 1000 cycles at 2C, significantly outperforming the performance of traditionally recycled powders. Attached Figure Description

[0030] Figure 1 This is an SEM image of the pretreated electrode sheet from Example 1.

[0031] Figure 2 This is a SEM image of the regenerated LFP powder from Example 1.

[0032] Figure 3 The specific capacity of the soft-pack battery prepared from the recycled LFP powder in Example 1 is compared with that of the waste lithium battery.

[0033] Figure 4 This is a comparison chart of the high and low temperature performance of pouch cells prepared using recycled SBR binder in Example 2 and pouch cells prepared using virgin materials. Detailed Implementation

[0034] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0035] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade reagents.

[0036] Example 1 This embodiment provides a system for continuous separation of binders in lithium iron phosphate electrode powder based on scCO2, and a separation method using this system.

[0037] The system includes a pretreatment unit, an scCO2 extraction unit, a series-connected cyclone separation unit, a binder collection unit, and an scCO2 circulation unit connected in sequence. The pretreatment unit is used to crush and sieve lithium iron phosphate electrodes; the scCO2 extraction unit includes an scCO2 extraction vessel, used to contact the electrode powder with scCO2 and remove the binder under adjustable temperature and pressure conditions; the series hydrocyclone separation unit is located at the outlet of the extraction vessel, used to depressurize the scCO2 fluid carrying the binder and achieve solid-gas separation; the series hydrocyclone separation unit includes a hydrocyclone separator (XF-CG-9) with a built-in ceramic membrane with a pore size of 0.1 μm, and is equipped with an electrostatic adsorption module with a voltage of ±5 kV; the binder collection unit includes an SBR collection tank and a PVDF collection tank, respectively connected to the series hydrocyclone separation unit, used to collect different types of binders, and a micro-metering pump is provided on the solid phase outlet pipeline connecting the PVDF collection tank and the series hydrocyclone separation unit; the scCO2 circulation unit is connected to the gas phase outlet and the inlet of the extraction vessel of the series hydrocyclone separation unit, used to realize the condensation, compression and reuse of scCO2.

[0038] The adhesive is then separated using the aforementioned system, the separation method comprising the following steps: S1. Pretreatment: The recycled PVDF-based electrode sheet is crushed to 150 μm using a universal pulverizer to obtain the pretreated electrode sheet (mass composition: LFP 92%, PVDF 6%, carbon black 2%). S2.scCO2 Extraction: The pretreated electrode sheets are fed into a supercritical CO2 extraction vessel with a packing density of 0.8 g / cm³. 3 The pressure was increased to 12 MPa at a rate of 5 MPa / min, and extracted for 40 min at 12 MPa, 45 °C, and a flow rate of 60 L / h. Then, the pressure was increased to 32 MPa at a rate of 5 MPa / min, and extracted for 120 min at 32 MPa, 55 °C, and a flow rate of 40 L / h, so that the binder on the electrode sheet could dissolve into scCO2 and fall off from the aluminum foil current collector. S3. Series hydrocyclone separation: The scCO2 carrying the binder flows out of the extraction vessel and into a series hydrocyclone separator group. After being depressurized to 7.4 MPa, solid-gas separation is performed by the hydrocyclone separator. The solid product is discharged through the solid phase outlet pipeline of the PVDF, and an anti-flocculation solution is added to the solid product by a micro metering pump. The anti-flocculation solution is a 0.1 wt% sodium dodecylbenzenesulfonate aqueous solution, and the amount added is 0.1 wt% of the mass of the pretreated electrode.

[0039] S4. Binder Collection: The solid product enters the PVDF collection tank through the solid product outlet pipeline to obtain the recovered PVDF binder; S5.scCO2 circulation: The separated scCO2 is discharged through the gas phase outlet of the series hydrocyclone separator, and after being condensed and compressed at 0℃ and 5MPa, it is circulated back to the inlet of the extraction vessel.

[0040] The regenerated LFP powder, after binder removal, was taken out of the supercritical CO2 extraction vessel and subjected to XPS analysis. The results showed that the PVDF residue ratio was 0.288%, and the carbon black loss rate was <5%. The molecular weight distribution of the PVDF regenerated powder (Mw / Mn=2.1) met the reuse standards.

[0041] SEM images of the pretreated electrode are shown below. Figure 1 As shown; SEM image of regenerated LFP powder is shown below. Figure 2 As shown in the image, a comparison of the microscopic morphology images before and after reveals that the treated LFP powder particles are more regular in shape, and the PVDF binder content is significantly reduced.

[0042] The recycled LFP powder from Example 1 was mixed uniformly with PVDF binder and conductive carbon black (Super P) in a mass ratio of 96.5:2.5:1 and coated onto carbon-coated aluminum foil to form the positive electrode material. A 10Ah soft-pack battery was prepared using a PP base film as the separator, Shanshan graphite FSN-1 material as the negative electrode, and 1M LiPF6 / EC-DMC as the electrolyte. The specific capacity and first-cycle efficiency of this soft-pack battery were tested according to the national standard GB / T31484-2015 "Requirements and Test Methods for Cycle Life of Power Batteries for Electric Vehicles". The specific capacity comparison is as follows: Figure 3 As shown, the solid line represents the performance of discarded lithium batteries, and the dashed line represents the performance of a 10Ah soft-pack battery, with the specific capacity significantly improved to 160mAh / g.

[0043] Furthermore, the assembled battery exhibits excellent electrochemical performance, with an initial charge-discharge efficiency of over 92%, and a capacity retention rate of over 85% after 1000 cycles at 2C rate. This indicates that the regenerated LFP powder has good structural and cycling stability, and can meet the application requirements of power and energy storage batteries for material performance.

[0044] Example 2 The testing system and procedures in Example 2 are basically the same as in Example 1, except that Example 2 uses recycled SBR base plates and pretreated plates (mass composition: G 94%, SBR 4%, carbon black 2%). Furthermore, the solid products from the separation step enter the SBR collection tank through the solid outlet pipeline to obtain recycled SBR binder.

[0045] The recycled LFP powder, after binder removal, was taken from the supercritical CO2 extraction vessel and subjected to XPS analysis. The results showed that the SBR residual ratio was 3.496%, and the carbon black loss rate was <5%. The molecular weight distribution of the SBR recycled powder (Mw / Mn=2.1) met the reuse standards.

[0046] The recycled SBR binder from Example 2 was mixed uniformly with graphite, CMC, and conductive carbon black (Super P) in a mass ratio of 2:96:1:1 and coated onto carbon-coated aluminum foil to form the negative electrode material. A PP base film was used as the separator. LFP powder was mixed uniformly with PVDF binder and conductive carbon black (Super P) in a mass ratio of 96.5:2.5:1 and coated onto carbon-coated aluminum foil to form the positive electrode material. A 10Ah soft-pack battery was prepared using 1M LiPF6 / EC-DMC as the electrolyte. The high-temperature performance of this soft-pack battery was tested according to the national standard GB / T 31484-2015, "Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles".

[0047] High-temperature performance of pouch batteries, such as Figure 4As shown in the figure, from right to left, each group of two solid lines represents the test performance under conditions of 45℃, 25℃, 10℃, 0℃, -10℃, and -20℃. Each group is a comparison graph of the discharge capacity performance of a pouch battery and a battery made using the new SBR material. The only difference between the two groups of cells is whether the SBR is recycled, which conforms to the single variable method. The left solid line in each group represents recycled material, and the right solid line represents new material. It can be seen that the high and low temperature performance of recycled SBR binder and new material is similar, indicating that recycled SBR binder has good high and low temperature performance and can meet the application requirements of power and energy storage batteries for material performance.

[0048] Comparative Example 1 The pretreated electrode sheets from Example 1 (mass composition: LFP 92%, PVDF 6%, carbon black 2%) were placed in a tube furnace and calcined under a high-purity nitrogen atmosphere. The temperature was increased to 550 °C at a rate of 5 °C / min and held for 4 hours to allow the PVDF in the electrode powder to undergo thermal decomposition and be removed from the surface of the active material. After calcination, the powder was cooled to room temperature under a nitrogen atmosphere, and the resulting regenerated LFP powder was collected.

[0049] The residual PVDF content in regenerated LFP powder was determined by thermogravimetric analysis (TGA) combined with fluorine elemental analysis. The results showed that the residual PVDF content in lithium iron phosphate powder was 0.451% after inert gas calcination.

[0050] Comparative Example 2 The pretreated electrode from Example 1 (mass composition: LFP 92%, PVDF 6%, carbon black 2%) was added to N-methylpyrrolidone (NMP) and stirred magnetically or mechanically at 90 °C for 6 h to allow PVDF to fully dissolve and desorb from the LFP and conductive agent surfaces. After the reaction was complete, solid-phase lithium iron phosphate powder and a PVDF-containing NMP solution were obtained by centrifugation or filtration.

[0051] The solid powder was washed multiple times with ethanol and deionized water and then vacuum dried at 80°C for 12 hours to obtain regenerated LFP powder. The NMP solution containing PVDF was recovered by vacuum distillation, and the residue at the bottom of the vessel was the recovered PVDF binder.

[0052] Thermogravimetric analysis (TGA) was used to determine the residual organic matter content of the regenerated LFP powder, and infrared analysis confirmed that the residual component was PVDF. The test results showed that the residual PVDF content in the regenerated LFP powder was 0.265%.

[0053] Comparative Example 3 The experimental procedures for this comparative example are basically the same as those for Example 1, except that the scCO2 extraction steps are as follows: 2. scCO2 extraction: The pretreated electrode sheets are fed into a supercritical CO2 extraction vessel with a packing density of 0.8 g / cm³. 3 The pressure was increased to 10 MPa at a rate of 5 MPa / min, and the extraction and separation were carried out for 160 min at 10 MPa, 45 °C and a flow rate of 60 L / h. This allowed the binder on the electrode to dissolve into scCO2 and detach from the aluminum foil current collector.

[0054] The remaining steps are the same as in Example 1. The regenerated LFP powder after the binder was removed was taken out of the supercritical CO2 extraction vessel and subjected to XPS detection. The detection results showed that the residual PVDF ratio in the regenerated LFP powder was 0.528%.

[0055] This invention combines staged pressure extraction with a series of hydrocyclones to achieve efficient desorption and separation of different binders in electrode powder. The overall recovery rate of binders can exceed 95%, and the recovery rate of lithium iron phosphate active material can exceed 99%, effectively avoiding the problems of incomplete separation and loss of active material in mechanical separation processes.

[0056] Furthermore, due to the low temperature and mild chemical environment throughout the process, and the absence of toxic organic solvents such as NMP, the high toxicity, high residue, and secondary pollution problems associated with traditional solvent recovery processes are avoided. This significantly reduces the damage to the lithium iron phosphate crystal structure and surface conductive network, ensuring that the regenerated lithium iron phosphate powder maintains good structural integrity and electrochemical activity. The recovered carbon dioxide is condensed and compressed within the system and then recycled, with virtually no external emissions, significantly reducing carbon emissions and wastewater generation.

[0057] The lithium iron phosphate powder recovered using this invention can be used to reconstitute lithium-ion batteries, achieving an initial charge-discharge efficiency exceeding 92%. After 1000 cycles at 2C, the capacity retention rate still exceeds 85%, significantly outperforming materials obtained through traditional recycling processes. This invention constructs a system structure integrating continuous feeding, supercritical extraction, online cyclone separation, anti-flocculation stabilization, and closed-loop carbon dioxide circulation. This allows for stable and continuous operation, reduces manual labor and equipment footprint, and improves processing efficiency, making it suitable for large-scale green recycling of power battery electrode powder.

[0058] This invention can also be implemented in various other ways. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for continuous separation of binder in lithium iron phosphate electrode powder based on scCO2, characterized in that, Includes the following steps: S1. Pretreatment: The electrode sheets are crushed and pretreated; S2.scCO2 extraction: The pretreated electrode is fed into a supercritical CO2 extraction vessel and extracted and separated under low pressure; the pressure is increased and then extracted and separated under high pressure, so that the binder dissolves into scCO2 and falls off from the aluminum foil current collector; S3. Series hydrocyclone separation: The scCO2 carrying the binder flows out of the extraction vessel and into the series hydrocyclone separator group. After depressurization, the hydrocyclone separator performs solid-gas separation, and an anti-flocculation solution is added to the solid product by a micro metering pump. S4. Binder Collection: The solid product enters a collection tank to obtain the recovered binder; S5.scCO2 circulation: The separated scCO2 is condensed, compressed, and then circulated back to the extraction vessel.

2. The method for continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 1, characterized in that, The size of the pretreated electrode is 140-160 μm; the packing density of the pretreated electrode into the supercritical CO2 extraction vessel is 0.7-0.9 g / cm³.

3. The method for continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 1, characterized in that, The supercritical CO2 extraction vessel is set with a flow rate of 40-60 L / h and a pressurization rate of 5 MPa / min.

4. The method for continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 1, characterized in that, The low-pressure extraction and separation pressure range is 10-15 MPa, the extraction temperature is 40-50℃, and the extraction time is 10-60 min.

5. The method for continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 1, characterized in that, The high-pressure extraction and separation process involves a pressure range of 25-35 MPa, an extraction temperature of 50-60℃, and an extraction time of 10-60 min.

6. The method for continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 1, characterized in that, The antiflocculation solution is an aqueous solution or an ethanol-water solution with a concentration of 0.1-0.5 wt% of antiflocculation agent; the rotation speed of the hydrocyclone is 3000-6000 rpm, and the separation time is 5-10 min.

7. The system for the method of continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to any one of claims 1-6, characterized in that, The system includes a pretreatment unit, an scCO2 extraction unit, a series-connected cyclone separation unit, a binder collection unit, and an scCO2 circulation unit connected in sequence. The pretreatment unit is used to crush and sieve the lithium iron phosphate electrode sheets; The scCO2 extraction unit includes an scCO2 extraction vessel, which is used to contact the electrode powder with scCO2 and remove the binder under adjustable temperature and pressure conditions; The series-connected cyclone separation unit is located at the outlet of the extraction vessel and is used to depressurize the scCO2 fluid carrying the binder and achieve solid-gas separation. The adhesive collection unit is connected to a series-connected cyclone separation unit for collecting different types of adhesives respectively. The scCO2 circulation unit is connected to the gas phase outlet and extraction vessel inlet of the series-connected cyclone separator unit, and is used to realize the condensation, compression and reuse of scCO2.

8. The system for the method of continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 7, characterized in that, The series-connected cyclone separator group is provided with a solid phase outlet, and the solid phase outlets of different cyclone separators are respectively connected to the SBR collection tank and the PVDF collection tank; at least one solid phase outlet pipeline of the series-connected cyclone separation unit is provided with an anti-flocculation agent addition unit.

9. The system for the method of continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 7, characterized in that, The cyclone separator has a built-in ceramic membrane with a pore size of 0.1 μm.

10. The system for the method of continuous separation of binder in lithium iron phosphate electrode powder based on scCO2 according to claim 7, characterized in that, The cyclone separator can also be equipped with an electrostatic adsorption module, the voltage of which is ±5 kV.

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