Electrolyte recycling device and method

Abstract

The invention relates to the technical field of electrolyte recycling, in particular to an electrolyte recycling device and method.The electrolyte recycling device comprises a filter box and a stirring box, a filter assembly is installed in the filter box and comprises two screws installed in the filter box, and a filter disc is in threaded connection between the two screws; a filter element is fixedly connected to the middle of the filter disc, a non-return membrane is fixedly connected to the middle of the filter disc, and a first motor is fixedly connected to the top end of the filter box; according to the scheme, impurities in the electrolyte are effectively filtered through vertical movement of the screw and the filter disc in the filter assembly, the electrolyte is separated out through the filter element under the action of pressure through the design of the filter element and the non-return membrane, meanwhile, the non-return membrane prevents the filtered electrolyte from flowing back according to the tricuspid valve principle of the heart, and therefore the filtering effect of the electrolyte is improved. And the unidirectivity and high efficiency of the filtering process are ensured, so that the recovery efficiency of the electrolyte is improved, the purity of the recovered electrolyte is also ensured, and subsequent reutilization is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolyte recovery, and in particular to an electrolyte recovery and utilization device and method. Background Art

[0002] With the widespread application of lithium-ion batteries in various fields, their recycling after the end of their service life has become an important issue. The electrolyte, as a key component of lithium-ion batteries, contains carbonate solvents and lithium hexafluorophosphate (LiPF6), etc. It not only has high economic value, but also causes serious pollution to the environment if improperly handled. Therefore, the development of effective electrolyte recovery technology is of great significance for the recycling of resources and environmental protection.

[0003] To this end, the present application proposes an electrolyte recycling device and method, which uses a filtering component to filter impurities in the electrolyte, the impurities include battery debris when the battery is disassembled, and impurities generated by the subsequent electrolyte during the reaction process. At the same time, a stirring component is used to stir the electrolyte and the reaction materials. Through precise chemical treatment and filtration steps, the waste electrolyte is restored to a performance standard similar to that of a commercial electrolyte, thereby achieving electrolyte recycling. Summary of the invention

[0004] Technical problem to be solved: The electrolyte contains carbonate solvents and lithium hexafluorophosphate, etc. Improper handling will cause serious pollution to the environment.

[0005] In view of the deficiencies in the prior art, the present invention provides an electrolyte recycling device and method, thereby solving the technical problems mentioned in the background technology.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: An electrolyte recycling device comprises a filter box and a stirring box, wherein a filter assembly is installed inside the filter box; The filter assembly comprises two screws installed in the filter box, a filter disc is threadedly connected between the two screws, a filter element is fixedly connected to the middle of the filter disc, a check membrane is fixedly connected to the middle of the filter disc, a motor 1 is fixedly connected to the top of the filter box, and the output end of the motor 1 is connected to the two screws through a pulley set; The filter box is connected to the stirring box through a connecting pipe and a pumping channel. A stirring assembly is installed inside the stirring box, and a feeding assembly is installed on the top of the stirring box.

[0007] In a possible implementation, the non-return membrane is placed on the upper side of the filter element. The non-return membrane is composed of multiple rubber sheets arranged in a ring shape. The edges of the multiple rubber sheets are squeezed together to form a cone shape. The non-return membrane uses the principle of the tricuspid valve of the heart.

[0008] In one possible implementation, the stirring assembly includes a rotating roller 1 installed inside a stirring box, a stirring frame 1 is fixedly connected to the middle of the rotating roller 1, a gear 1 is fixedly connected to one end of the rotating roller 1, a stirring frame 2 is sleeved on the outside of the rotating roller 1, a tooth groove is opened on one side of the stirring frame 2, an inner gear 2 is fixedly connected to the inner wall of the tooth groove, a motor 2 is fixedly connected to the outside of the stirring box, and a gear 3 is fixedly connected to the output end of the motor 2.

[0009] In a possible implementation, the gear one is arranged inside the tooth groove, and the gear three is meshed between the gear one and the internal gear two.

[0010] In one possible implementation, the feeding assembly includes a plurality of storage boxes fixed on the top of a mixing box, the top of the storage boxes is fixedly connected to a motor three, the output end of the motor three is fixedly connected to a rotating roller two, an auger is installed on the lower side of the rotating roller two, a weighing box is provided on the lower side of the storage boxes, and a weighing plate is rotatably connected to the middle of the weighing box.

[0011] In one possible implementation, a rotating rod is fixedly connected to one side of the weighing plate, a connecting rod is rotatably connected to the side of the rotating rod away from the weighing plate, the other end of the connecting rod is rotatably connected to a pneumatic rod, and air pipes are connected between the input ends of multiple pneumatic rods.

[0012] In a possible implementation, the input end of the air pipe is connected to a pneumatic device.

[0013] In a possible implementation, the plurality of storage boxes (19) contain various types of powdered chemical raw materials, and the materials inside each storage box (19) are fluoroethylene carbonate (FEC), lithium nitrate ( )、Lithium difluorooxalate borate (LiDFOB), 4-mercaptopyridine (4Mpy), sodium carbonate ( ).

[0014] In a possible implementation, a slag discharge cover is installed at the bottom end of the filter box.

[0015] In a possible implementation, an electrolyte recycling method applied to the above-mentioned electrolyte recycling device includes the following steps: Step 1: Preliminary filtration: The filtered electrolyte may contain battery fragments and impurities. The filtered electrolyte is pushed into the mixing box through the anti-return membrane; Step 2: primary reaction, adding fluoroethylene carbonate into the interior of the stirring box through the feeding assembly, lithium ion desolvation energy barrier, and decomposition on the surface of metallic lithium to form a layer rich in solid electrolyte interface film; Step 3: secondary filtration: after the primary reaction is completed, the electrolyte and impurities in the stirring box are sent to the inside of the filter box through the pumping channel, and secondary filtration is performed on them through the filtering component to filter out the vinylene carbonate and difluoroethylene carbonate impurities that may be contained in the fluoroethylene carbonate in the primary reaction, and the filtered electrolyte is pushed to the inside of the stirring box through the check membrane; Step 4: secondary reaction, adding lithium nitrate into the interior of the stirring box through the feeding assembly, introducing nitrate into the lithium ion solvation shell, promoting the decomposition of the bis(fluorosulfonyl)imide anion, and forming an interface layer rich in lithium fluoride; Step 5: a third reaction, adding lithium difluorooxalate borate to the interior of the stirring box through a feeding assembly, wherein the lithium difluorooxalate borate is preferentially oxidized to form a boron-containing polymer component, which helps to form a stable positive electrode electrolyte interface layer; Step 6: Three filtrations: After the first reaction is completed, the electrolyte and impurities in the stirring box are sent to the inside of the filter box through the pumping channel, and filtered three times through the filtering component to filter out some insoluble impurities generated during the synthesis of lithium difluorooxalate borate. The filtered electrolyte is pushed to the inside of the stirring box through the check membrane; Step 7: Four reactions, adding 4-mercaptopyridine into the stirring box through the feeding assembly as an electrolyte additive to dynamically adjust the polysulfide conversion path and slow down the shuttling of polysulfides; Step 8: After the fifth reaction, sodium carbonate is added into the mixing box through the feeding component to adjust the pH value of the electrolyte.

[0016] Beneficial effects compared with the prior art: 1. In this scheme, the impurities in the electrolyte are effectively filtered by the up and down movement of the screw and filter disc in the filter assembly. The design of the filter element and the check membrane allows the electrolyte to precipitate through the filter element under pressure. At the same time, the check membrane uses the principle of the tricuspid valve of the heart to prevent the filtered electrolyte from flowing back, ensuring the unidirectionality and high efficiency of the filtration process. This design not only improves the recovery efficiency of the electrolyte, but also ensures the purity of the recovered electrolyte, which is conducive to subsequent reuse; 2. In this solution, the electrolyte and the added chemical raw materials can be fully mixed and reacted in the stirring box through the design of the stirring component. The stirring frame 1 and the stirring frame 2 driven by the motor 2 rotate in opposite directions. This stirring method can accelerate the reaction process of the electrolyte and the chemical material and improve the reaction efficiency. By accurately controlling the addition amount of the chemical raw materials and the stirring process, the recovery and reuse effect of the electrolyte can be optimized and the waste of resources can be reduced; 3. In this scheme, through precise chemical treatment and filtration steps, the spent electrolyte is restored to performance standards similar to those of commercial electrolytes. The restored electrolyte exhibits a high ionic conductivity of 2.2 S·cm^-1 and an apparent activation energy of 4.73 kJ / mol at 293.15 K, which are very similar to commercial electrolytes with the same composition. This indicates that the regenerated electrolyte can provide battery performance comparable to that of new electrolytes, which is of great significance for promoting the development and popularization of battery technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of an electrolyte recycling device; Figure 2 A schematic diagram of a filter disc of an electrolyte recovery and utilization device; Figure 3 A schematic diagram of a check membrane of an electrolyte recycling device; Figure 4 A schematic diagram of a stirring frame 2 of an electrolyte recycling device; Figure 5 A schematic diagram of gear 3 of an electrolyte recycling device; Figure 6 A schematic diagram of a storage box of an electrolyte recycling device; Figure 7 for Figure 1 Enlarged view of point A in the middle; Figure 8 A step diagram of an electrolyte recycling method.

[0019] Legend: 1. Filter box; 2. Screw; 3. Motor 1; 4. Pulley assembly; 5. Filter disc; 6. Filter element; 7. Check membrane; 8. Slag discharge cover; 9. Connecting pipe; 10. Mixing box; 11. Rotating roller 1; 12. Mixing frame 1; 13. Mixing frame 2; 14. Gear 1; 15. Tooth groove; 16. Internal gear 2; 17. Motor 2; 18. Gear 3; 19. Storage box; 20. Rotating roller 2; 21. Motor 3; 22. Auger; 23. Weighing box; 24. Weighing plate; 25. Rotating rod; 26. Connecting rod; 27. Pneumatic rod; 28. Air pipe; 29. ​​Pumping channel. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in various forms, so the present invention is not limited to the embodiments described below. In addition, in order to more clearly describe the present invention, components that are not connected with the invention will be omitted from the drawings. The technical solution in the embodiment of the present application is to solve the problems of the above-mentioned background technology, and the overall idea is as follows: Embodiment 1: Please refer to Figure 1 - Figure 7 As shown, this embodiment introduces a specific structure of an electrolyte recycling device, including a filter box 1 and a stirring box 10. A filter assembly is installed inside the filter box 1. The filter box 1 is connected to the stirring box 10 through a connecting pipe 9 and a pumping channel 29. A stirring assembly is installed inside the stirring box 10. A feeding assembly is installed at the top of the stirring box 10. The filter assembly includes two screw rods 2 rotatably connected to the inside of the filter box 1, a motor 3 is fixedly connected to the top of the filter box 1, the output end of the motor 3 is connected to the top of one of the screw rods 2, a pulley group 4 is fixedly connected between the tops of the two screw rods 2, a filter disc 5 is threadedly connected between the two screw rods 2, and a filter element 6 is fixedly connected to the middle of the filter disc 5. In the initial state, the filter disc 5 is at the top of the inside of the filter box 1. When the disassembled and removed electrolyte is transported to the inside of the filter box 1, the motor 3 is started to drive the two screw rods 2 to rotate simultaneously through the pulley group 4. When the screw 2 rotates, it will drive the filter disc 5 to move up and down. When the filter disc 5 moves downward, the filter disc 5 will squeeze the electrolyte inside the filter box 1. Under the action of pressure, the electrolyte inside the filter box 1 will precipitate through the filter element 6, thereby filtering the impurities in the battery. The middle of the filter disc 5 is fixedly connected with a check membrane 7, which is placed on the upper side of the filter element 6. The check membrane 7 is composed of a plurality of rubber sheets arranged in a ring shape, and the edges of the plurality of rubber sheets are mutually squeezed to form a cone shape. The check membrane 7 uses the principle of the tricuspid valve of the heart. When the filter disc 5 moves downward, after the electrolyte is precipitated through the filter element 6, under the action of pressure, the plurality of rubber sheets will open to form a passage, and the filtered electrolyte will pass through the check membrane 7 and be discharged to the top of the check membrane 7; When the filter disc 5 moves to the bottom of the filter box 1, the electrolyte is basically filtered. At this time, the edge of the rubber sheet closes again under the action of the rubber's own rebound force, thereby preventing the filtered electrolyte from flowing back to the lower side of the filter disc 5. Then the motor 3 reverses to drive the screw 2 to reverse and then drive the filter disc 5 to move upward. Since the check membrane 7 is in a closed state, the filtered electrolyte is pushed upward when the filter disc 5 moves upward, and the electrolyte flows to the inside of the stirring box 10 through the connecting pipe 9. The stirring assembly includes a rotating roller 11 installed inside the stirring box 10, a stirring frame 12 is fixedly connected to the middle of the rotating roller 11, a gear 14 is fixedly connected to one end of the rotating roller 11, a stirring frame 13 is sleeved on the outside of the rotating roller 11, a tooth groove 15 is opened on one side of the stirring frame 13, an inner gear 2 16 is fixedly connected to the inner wall of the tooth groove 15, a motor 2 17 is fixedly connected to the outside of the stirring box 10, a gear 3 18 is fixedly connected to the output end of the motor 2 17, the gear 14 is arranged inside the tooth groove 15, and the gear 3 18 is meshed with the inner wall of the tooth groove 15. Between gear 14 and internal gear 2 16, when the chemical powder is fed into the mixing box 10 through the feeding assembly, the motor 2 17 is started, and the motor 2 17 drives the gear 3 18 to drive the gear 14 and the internal gear 2 16 to rotate in the opposite direction, and the gear 14 drives the rotating roller 11 to drive the stirring frame 12 to rotate, and the internal gear 2 16 drives the stirring frame 2 13 to rotate, and then the stirring frame 12 and the stirring frame 2 13 rotate in the opposite direction, so as to fully stir the electrolyte and chemical powder in the mixing box 10 and improve the reaction rate; The feeding assembly includes a plurality of storage boxes 19 fixed on the top of the mixing box 10, the top of the storage box 19 is fixedly connected to a motor 3 21, the output end of the motor 3 21 is fixedly connected to a rotating roller 20, the rotating roller 20 rotates inside the storage box 19, the bottom end of the rotating roller 20 is fixedly connected to an auger 22, a weighing box 23 is provided on the lower side of the storage box 19, the middle part of the weighing box 23 is rotatably connected to a weighing plate 24, one side of the weighing plate 24 is fixedly connected to a rotating rod 25, and the side of the rotating rod 25 away from the weighing plate 24 is rotatably connected to a connecting rod 26, the feeding assembly also includes a pneumatic device, the output end of the pneumatic device is connected to an air pipe 28, the air pipe 28 is fixedly connected to a plurality of pneumatic rods 27, and the output ends of the pneumatic rods 27 are rotatably connected to a plurality of connecting rods 26, and the interiors of the plurality of storage boxes 19 are filled with various chemical raw materials, and the chemical raw materials inside are all powder materials, and the materials inside each storage box 19 are fluoroethylene carbonate ( FEC), lithium nitrate ( )、Lithium difluorooxalate borate (LiDFOB), 4-mercaptopyridine (4Mpy), sodium carbonate ( ), when it is necessary to add material to the inside of the mixing box 10, start the motor three 21, the motor three 21 drives the rotating roller two 20 to rotate and then drives the auger 22 to rotate, and when the auger 22 rotates, the material inside the storage box 19 is sent to the inside of the weighing box 23 and falls on the weighing plate 24. As the material falls, the weighing plate 24 will continuously weigh the material. When the weight reaches the standard, the motor three 21 stops rotating. At this time, the pneumatic equipment starts, and the pneumatic rod 27 is supplied with air and then pushed to extend. The pneumatic rod 27 pushes the connecting rod 26 to extend and then pushes the rotating rod 25 to rotate, thereby realizing the flipping of the weighing plate 24, and then realizing the dumping of the material on the weighing plate 24 into the inside of the mixing box 10. After the dumping is completed, the pneumatic rod 27 contracts and then drives the weighing plate 24 to reset.

[0021] The bottom end of the mixing box 10 is connected to the filter box 1 through a pumping channel 29. Its function is to produce waste residue after the electrolyte reacts with the chemical material. The electrolyte and waste residue inside the mixing box 10 can be transported to the inside of the filter box 1 through the delivery pump on the pumping channel 29, and filtered twice or multiple times through the filtering component. The filtered waste residue can be discharged through the residue discharge cover 8, and the filter element 6 can be replaced through the residue discharge cover 8.

[0022] Embodiment 2: Please refer to Figure 8 As shown, an electrolyte recycling method applied to an electrolyte recycling device in Example 1, the specific steps are as follows: Step 1: Primary filtration: after the disassembled battery, the electrolyte may contain electromagnetic debris impurities, etc., so it needs to be filtered. The electrolyte is taken out and pumped into the filter box 1, and is filtered for the first time through the filter assembly. The filtered electrolyte is pushed into the mixing box 10 through the check membrane 7; Step 2: primary reaction, adding fluoroethylene carbonate (FEC) to the interior of the stirring box 10, FEC molecules participate in the lithium ion solvation shell, reduce the lithium ion desolvation energy barrier, and decompose on the surface of the metal lithium to form a solid electrolyte interface film (SEI) layer rich in lithium fluoride (LiF), the chemical reaction formula is: ; Step 3: secondary filtration. In the first reaction, fluoroethylene carbonate (FEC) may contain VC (vinylene carbonate) and DFEC (difluoroethylene carbonate) impurities. After the first reaction is completed, the electrolyte and impurities in the stirring box 10 are sent to the inside of the filter box 1 through the pumping channel 29, and are subjected to secondary filtration by the filter component. The filtered electrolyte is pushed into the inside of the stirring box 10 through the check membrane 7; Step 4: Secondary reaction, adding lithium nitrate ( ), introducing nitrate into the lithium ion solvation shell and promoting the bis(fluorosulfonyl)imide anion ( Anions) decompose to form an interface layer rich in lithium fluoride (LiF), the chemical reaction formula is: , the nitrate reacts with the lithium ion in the solvation shell: ; Step 5: Three reactions, adding lithium difluorooxalate borate (LiDFOB), lithium difluorooxalate borate (LiDFOB) is preferentially oxidized to form a boron-containing polymer component, which helps to form a stable cathode electrolyte interface CEI layer. The chemical reaction formula is: ; Step 6: Three filtrations. During the synthesis process of lithium difluorooxalatoborate (LiDFOB), some insoluble impurities, such as lithium oxalate and lithium fluoride, may be generated. These impurities may cause turbidity in the electrolyte. Therefore, they may need to be removed by filtration before use. After the three reactions are completed, the electrolyte and impurities in the stirring box 10 are sent to the inside of the filter box 1 through the pumping channel 29. The electrolyte is filtered three times by the filter assembly. The filtered electrolyte is pushed to the inside of the stirring box 10 through the check membrane 7. Step 7: Four reactions, adding 4-mercaptopyridine (4Mpy) as an electrolyte additive to dynamically adjust the polysulfide conversion path and slow down the shuttling of polysulfides. The chemical reaction formula is: ; Step 8: Five reactions, adding sodium carbonate ( ), adjust the pH value of the electrolyte, the chemical reaction formula is: , at this point the waste electrolyte can be restored to a certain usable state.

[0023] Through precise chemical treatment and filtration steps, the electrolyte can be restored and regenerated to achieve performance standards similar to those of commercial electrolytes. The regenerated electrolyte exhibits a high ionic conductivity of 2.2 S·cm^-1 and an apparent activation energy of 4.73 kJ / mol at 293.15 K, which is very similar to commercial electrolytes with the same composition. This is of great significance for promoting the development and popularization of battery technology.

[0024] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. An electrolyte recycling device, comprising a filter box (1) and a stirring box (10), wherein the filter box (1) is cyclically connected to the stirring box (10) via a connecting pipe (9) and a pumping channel (29), a stirring assembly is installed inside the stirring box (10), and a feeding assembly is installed at the top of the stirring box (10), characterized in that: A filter assembly is installed inside the filter box (1); A filter assembly comprises two screw rods (2) installed in a filter box (1), a filter disc (5) being threadedly connected between the two screw rods (2), a filter element (6) being fixedly connected to the middle of the filter disc (5), a check membrane (7) being fixedly connected to the middle of the filter disc (5), a motor 1 (3) being fixedly connected to the top of the filter box (1), and an output end of the motor 1 (3) being connected to the two screw rods (2) via a pulley group (4).

2. An electrolyte recycling device according to claim 1, characterized in that: The non-return membrane (7) is placed on the upper side of the filter element (6); the non-return membrane (7) is composed of a plurality of rubber sheets arranged in a ring shape; the edges of the plurality of rubber sheets are mutually squeezed at their joints to form a cone shape; the non-return membrane (7) uses the principle of the tricuspid valve of the heart.

3. The electrolyte recycling device according to claim 1, characterized in that: The stirring assembly comprises a rotating roller (11) installed inside a stirring box (10), a stirring frame (12) being fixedly connected to the middle of the rotating roller (11), a gear (14) being fixedly connected to one end of the rotating roller (11), a stirring frame (13) being sleeved on the outside of the rotating roller (11), a tooth groove (15) being provided on one side of the stirring frame (13), an inner gear (16) being fixedly connected to the inner wall of the tooth groove (15), a motor (17) being fixedly connected to the outside of the stirring box (10), and a gear (18) being fixedly connected to the output end of the motor (17).

4. An electrolyte recycling device as claimed in claim 3, characterized in that: The gear one (14) is arranged inside the tooth groove (15), and the gear three (18) is meshed between the gear one (14) and the internal gear two (16).

5. The electrolyte recycling device according to claim 1, characterized in that: The feeding assembly comprises a plurality of material storage boxes (19) fixed on the top of the mixing box (10); the top of the material storage box (19) is fixedly connected to a motor three (21); the output end of the motor three (21) is fixedly connected to a rotating roller two (20); an auger (22) is installed on the lower side of the rotating roller two (20); a weighing box (23) is provided on the lower side of the material storage box (19); and a weighing plate (24) is rotatably connected to the middle of the weighing box (23).

6. An electrolyte recycling device as claimed in claim 5, characterized in that: A rotating rod (25) is fixedly connected to one side of the weighing plate (24); a connecting rod (26) is rotatably connected to the side of the rotating rod (25) away from the weighing plate (24); a pneumatic rod (27) is rotatably connected to the other end of the connecting rod (26); and an air pipe (28) is connected between the input ends of the plurality of pneumatic rods (27).

7. An electrolyte recycling device as claimed in claim 6, characterized in that: The input end of the air pipe (28) is connected to a pneumatic device.

8. An electrolyte recycling device as claimed in claim 5, characterized in that: Various types of powdered chemical raw materials are contained in the plurality of storage boxes (19), and the materials contained in each storage box (19) are fluoroethylene carbonate, lithium nitrate, lithium difluorooxalatoborate, 4-mercaptopyridine, and sodium carbonate.

9. The electrolyte recycling device according to claim 1, characterized in that: A slag discharge cover (8) is installed at the bottom end of the filter box (1).

10. An electrolyte recycling method applied to an electrolyte recycling device according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Preliminary filtration, in which the electrolyte may contain battery fragments and impurities, and the filtered electrolyte is pushed into the interior of the stirring box (10) through the anti-return membrane (7); Step 2: a primary reaction, adding fluoroethylene carbonate into the interior of the stirring box (10) through a feeding assembly, desolvating the lithium ions from the energy barrier, and decomposing on the surface of the metallic lithium to form a layer rich in a solid electrolyte interface film; Step 3: secondary filtration, after the primary reaction is completed, the electrolyte and impurities in the stirring box (10) are sent to the inside of the filter box (1) through the pumping channel (29), and secondary filtration is performed on them through the filtering component to filter out the vinylene carbonate and difluoroethylene carbonate impurities that may be contained in the fluoroethylene carbonate in the primary reaction, and the filtered electrolyte is pushed into the inside of the stirring box (10) through the anti-return membrane (7); Step 4: secondary reaction, adding lithium nitrate into the interior of the stirring box (10) through the feeding assembly, introducing nitrate into the lithium ion solvation shell, promoting the decomposition of the bis(fluorosulfonyl)imide anion, and forming an interface layer rich in lithium fluoride; Step 5: a third reaction, wherein lithium difluorooxalate borate is added into the stirring box (10) through a feeding assembly, and the lithium difluorooxalate borate is preferentially oxidized to form a boron-containing polymer component, which helps to form a stable positive electrode electrolyte interface layer; Step 6: three filtrations. After the first reaction is completed, the electrolyte and impurities in the stirring box (10) are sent to the inside of the filter box (1) through the pumping channel (29). The electrolyte and impurities are filtered three times by the filtering component to filter out some insoluble impurities generated during the synthesis of lithium difluorooxalate borate. The filtered electrolyte is pushed into the inside of the stirring box (10) through the check membrane (7); Step 7: Four reactions, adding 4-mercaptopyridine into the stirring box (10) through the feeding assembly as an electrolyte additive to dynamically adjust the polysulfide conversion path and slow down the shuttling of polysulfides; Step 8: After the fifth reaction, sodium carbonate is added into the stirring box (10) through the feeding component to adjust the pH value of the electrolyte.

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