Method for preparing a button-type semi-solid supercapacitor

Abstract

The application relates to a preparation method of a button-type semi-solid super capacitor and belongs to the field of lithium battery industries. The preparation method of the semi-solid electrolyte comprises the following steps: mixing polyethylene glycol and acetonitrile electrolyte, stirring in a vacuum state, obtaining a mixed solution M, adding tetraethyl orthosilicate into the mixed solution M, stirring in a vacuum state, obtaining a mixed solution N, adding a double-diazine crosslinking agent, stirring in a vacuum state, and obtaining the semi-solid electrolyte. The preparation method of the button-type semi-solid super capacitor comprises the following steps: mixing active carbon, a conductive agent and a binder according to a certain proportion, airflow crushing, baking the pole piece at high temperature, coating the conductive glue in the positive and negative pole shell covers and baking, immersing the pole piece and the diaphragm in the acetonitrile electrolyte, coating a layer of semi-solid electrolyte on the surface of the pole piece after draining, and assembling and sealing. A protective film is formed on the surface of the pole piece, the acetonitrile electrolyte is prevented from flowing into the shell cover, and the liquid leakage is reduced.

Description

Technical Field

[0001] This invention relates to a method for preparing a button-type semi-solid supercapacitor, belonging to the field of supercapacitor industry. Background Technology

[0002] Energy is the driving force upon which human society depends for survival. With rapid socio-economic development and rising living standards, the demand for non-renewable resources such as coal, oil, and natural gas is increasing. Faced with the growing scarcity of non-renewable resources and the escalating degradation of the ecological environment, a highly efficient energy storage device is crucial for better utilization of new energy resources and more rational resource allocation. Among these, supercapacitors, with their rapid charging and discharging, high power density, and ultra-long cycle life, have attracted significant attention and research, making them a promising energy storage device.

[0003] Supercapacitors are a new type of energy storage device. Their principle is based on porous carbon, conductive polymers, etc., to achieve energy storage through rapid charging and discharging at the electrode surface-electrolyte interface. The emergence of supercapacitors fills the gap between traditional capacitors and batteries. Future multifunctional consumer electronics products require novel functions and features such as thinner, lighter, more flexible, and transparent designs. Therefore, supercapacitors have broad application prospects in many fields, including medical and health, electric vehicles, mobile communications, and military industries, and have received high attention from countries around the world.

[0004] With the increasing application scenarios of supercapacitors, some applications, such as streetlights and barbecue grills, are placing increasingly stringent demands on their high-temperature performance. Currently, most button-type supercapacitors on the market use liquid electrolyte to improve its conductivity. However, insufficient liquid electrolyte can lead to inadequate ion conduction pathways within the electrode layer, resulting in reduced rate capability. Conversely, excessive liquid electrolyte can leak from the electrode layer, corroding the circuit boards and rendering the equipment unusable. To address the issue of electrolyte leakage leading to product failure in supercapacitors, improvements can be made in two main areas: 1. Optimizing the product's structural design; 2. Enhancing the product's high-temperature performance. To optimize product structure and enable it to operate in high-temperature environments without leakage, there are two main directions for improvement. One is to protect the supercapacitor so that leaked electrolyte will not affect the circuit board. The main methods for this are: ① wrapping the supercapacitor with a plastic shell; ② coating the surface of the supercapacitor with a layer of resin. The other direction is to solve the leakage problem during use by improving the sealing process and using semi-solid electrolytes during the supercapacitor packaging and production process. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a method for preparing a button-type semi-solid supercapacitor, which can solve the problem of electrolyte leakage in supercapacitors leading to product failure.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The method for preparing the button-type semi-solid supercapacitor of the present invention includes the following steps: 1) Mix activated carbon, conductive agent, and binder in a certain proportion; 2) The mixture is subjected to air jet milling; 3) Roll the electrode sheet to the required thickness; 4) The rolled electrode sheets are stamped into a certain shape using a die; 5) Bake the electrode at high temperature; 6) Apply conductive adhesive X to the positive and negative electrode shells and bake; 7) Immerse the baked electrode and diaphragm in acetonitrile electrolyte, drain them, and then coat the electrode surface with a layer of semi-solid electrolyte. 8) Assemble the electrode in the following order: shell cover - electrode plate - diaphragm - electrode plate - shell cover; 9) Seal the opening.

[0007] According to the preparation method of the button-type semi-solid supercapacitor, in step 1), the activated carbon and conductive agent need to be dehydrated first. The dehydration temperature is 80~200℃ and the time is 1~5h. The activated carbon is one or more of YP-50F, BAC-1, DR80, and CEP21KSN. The conductive agent is one or more of Super-P, KS-15, carbon nanotubes, ECP, and acetylene black. The binder is one or more of F104, F106, and F208.

[0008] According to the method for preparing the button-type semi-solid supercapacitor, in step 2), the airflow pulverization speed is 1~2 kg / h and the pressure is 0.4~0.9 MPa; in step 3), the thickness of the electrode is 0.5~1.0 mm; and in step 4), the diameter of the stamped electrode is 6.5~13.5 mm.

[0009] According to the method for preparing the button-type semi-solid supercapacitor, in step 5), the baking temperature of the electrode is 80~250℃, the time is 3~24h, and the vacuum degree is ≤-90Kpa. In step 6), the conductive adhesive X is coated on the inner surface of the shell with a thickness of 3~7μm, and the baking temperature of the shell coated with conductive adhesive X is 60~150℃, and the time is 3~24h.

[0010] According to the aforementioned method for preparing the button-type semi-solid supercapacitor, the method for preparing the semi-solid electrolyte... 1) Mix polyethylene glycol and acetonitrile electrolyte, and stir under vacuum at 10~35℃ for 1~10h to obtain mixture M; 2) Add tetraethyl orthosilicate dropwise to the mixture M from step 1, and stir under vacuum at 10~35℃ for 1~10h to obtain mixture N; 3) Add a diazoxide heterocyclic crosslinking agent to the mixture N in step 2, and stir under vacuum at 10~35℃ for 1~10h to obtain a semi-solid electrolyte.

[0011] According to the method for preparing the semi-solid electrolyte for capacitors, the mass ratio of polyethylene glycol to acetonitrile electrolyte is 0.1~0.3:1; the mass ratio of N in the mixture to bis(diazo) heterocyclic crosslinking agent is 10~100:1; and the number average molecular weight of polyethylene glycol is 10000~18000.

[0012] According to the method for preparing the semi-solid electrolyte for capacitors, the salt in the acetonitrile electrolyte is at least one of tetraethylammonium tetrafluoroborate, methyltriethylammonium tetrafluoroborate, and 1,1-spirobispyrrolidineonium tetrafluoroborate.

[0013] According to the method for preparing the button-type semi-solid supercapacitor, the characteristic is that the diaphragm baking method in step 7) is the same as the shell baking method in step 6), the electrode and diaphragm are immersed in the solution for 10~30 min, the semi-solid electrolyte is coated on the electrode with a thickness of 2~8 μm, and steps 8) and 9) need to be completed in a drying room at a temperature of 10~35℃ and a dew point of -70~-20℃.

[0014] According to the method for preparing the button-type semi-solid supercapacitor, the conductive adhesive X is characterized by using CMC, polyolefin resin, conductive agent, and deionized water as raw materials, and the preparation process includes... 1) Add CMC to deionized water and stir at 10~35℃ for 1~3 hours to obtain mixture A; 2) Mix mixture A with polyolefin resin emulsion and stir under vacuum at 10~35℃ for 2~5 hours to obtain mixture B; 3) Add conductive agent to mixture B, stir at 10~35℃ for 10~50 min, and stir at 10~35℃ under vacuum for 1~3 h to obtain conductive adhesive.

[0015] According to the method for preparing the button-type semi-solid supercapacitor, the deionized water to CMC mass ratio is 50~200:1, the mixture A to polyolefin resin emulsion mass ratio is 1:10~100, the mixture B to conductive agent mass ratio is 5~30:1, the conductive adhesive is coated on the positive and negative electrode shells of the supercapacitor with a coating thickness of 3~7μm, and the shells coated with conductive adhesive are baked at a temperature of 60~150℃ for 3~24h.

[0016] According to the method for preparing the button-type semi-solid supercapacitor, the conductive agent is one or more of Super-P, KS-15, carbon nanotubes, ECP, and acetylene black, and the surface of the shell is free from rust, oil stains, plastic flash, and gaps.

[0017] This patent improves the high-temperature performance of button-type products while reducing leakage by improving the formulation of conductive adhesive and semi-solid electrolyte.

[0018] When using the improved conductive adhesive to manufacture supercapacitors, the internal resistance of the product can be significantly reduced, greatly increasing the product's lifespan. The semi-solid electrode liquid has poor fluidity, forming a protective film on the electrode surface, while also preventing the electrolyte from flowing into the casing. It only works inside the electrode, reducing leakage and improving the problem of electrolyte leakage leading to product failure in supercapacitors. Attached Figure Description

[0019] Figure 1 Flowchart for the fabrication of a semi-solid electrolyte supercapacitor; Figure 2 This is a comparison chart of the internal resistance growth rate curves for Example 1 and Example 3. Implementation

[0020] The technical solutions of the present invention will be further described below with reference to the accompanying drawings. The described solutions are only some embodiments and do not constitute any limitation on the present invention. Other modifications may be made within the scope of the technical solutions described in the claims. All improvements, modifications, and substitutions made based on the principles and spirit of the present invention should be protected by the present invention.

[0021] Example 1

[0022] The specific details of this invention will be further explained below: The present invention discloses a method for preparing a button-type semi-solid supercapacitor, which includes the following steps: preparation of a semi-solid electrolyte, preparation of conductive adhesive X, and preparation of the supercapacitor.

[0023] The preparation of the semi-solid electrolyte includes the following steps: 1) Mix 10g of polyethylene glycol and 90g of acetonitrile electrolyte, stir at 25°C for 2h, and vacuum degree ≤-99Kpa to obtain a 10% polyethylene glycol solution M. The number average molecular weight of the polyethylene glycol is 15000, and the ammonium salt of the acetonitrile electrolyte is ammonium methyltriethyltetrafluoroborate.

[0024] 2) Then, slowly add 1.5 mL of tetraethyl orthosilicate to a 10% polyethylene glycol solution M at a rate of 1 drop / second, stir at 25°C for 1.5 h, and maintain a vacuum of ≤-99 kPa to obtain a mixed solution N.

[0025] 3) Add 1g of bis(diazo) heterocyclic crosslinking agent to the mixture N, stir at 25℃ for 4h, and vacuum degree ≤-99Kpa to obtain a semi-solid electrolyte.

[0026] The preparation of conductive adhesive X specifically includes the following steps: 1) Mix 99g of deionized water and 1g of CMC, and stir at 25°C for 2 hours to obtain mixture A.

[0027] 2) Mix 100g of mixture A and 3000g of polyolefin resin, stir at 25℃ for 4h, and vacuum degree ≤-99Kpa to obtain mixture B.

[0028] 3) Add 200g Super-P and 110g carbon nanotubes to 3100g of mixture B, stir at 25℃ for 30min, then turn on the vacuum and continue stirring at 25℃ for 3h under the condition of vacuum degree ≤-99Kpa to obtain conductive adhesive X.

[0029] The fabrication method of a button-type semi-solid-state supercapacitor specifically includes the following steps: First, dehydrate the activated carbon and conductive agent at 140℃ for 3 hours. Then, put the dehydrated activated carbon BAC-1, conductive agent Super-P and binder F104 into a V-type mixer at a ratio of 90:4:6 and stir at 25℃ for 3 hours.

[0030] Add the mixture from step 1) to an air jet mill for pulverization at a speed of 2 kg / h and a pressure of 0.8 MPa.

[0031] The material from step 2) is repeatedly rolled using a roller press to form an electrode sheet with a thickness of 0.8 mm.

[0032] The 0.8mm thick electrode sheet is stamped into an electrode sheet with a diameter of 12mm.

[0033] Electrodes with a thickness of 0.8 mm and a diameter of 12 mm were vacuum-baked at 120℃ for 24 hours, with a vacuum degree ≤-90 kPa.

[0034] The inner surface of the shell is coated with a 5-6 μm thick conductive adhesive X and then vacuum baked at 90℃ for 24 hours with a vacuum degree ≤-90Kpa.

[0035] The diaphragm was vacuum-baked at 90℃ for 24 hours with a vacuum degree ≤-90Kpa. The baked electrode and diaphragm were then immersed in acetonitrile electrolyte for 15 minutes. After draining, a 3~5μm thick semi-solid electrolyte was coated on the surface of the electrode.

[0036] The electrodes are assembled and sealed in the drying chamber in the following order: shell cover - electrode plate - diaphragm - electrode plate - shell cover. The temperature of the drying chamber is 25℃ and the dew point is -70~-60℃.

[0037] Example 2

[0038] The difference between Example 2 and Example 1 is that, In Example 2, the electrode was directly immersed in acetonitrile electrolyte for 15 minutes without coating the electrode surface with semi-solid electrolyte; the number average molecular weight of the polyethylene glycol was 15,000, and the electrolyte salt of the acetonitrile electrolyte was ammonium methyltriethyltetrafluoroborate.

[0039] Example 3

[0040] The difference between Example 3 and Example 1 is that, In Example 3, the inner surface of the shell cover is coated with the original conductive adhesive, while in Example 1, the inner surface of the shell cover is coated with the improved conductive adhesive X. The conductive adhesive X contains 3000g of polyolefin resin, 200g of Super-P, 110g of carbon nanotubes, 99g of deionized water, and 1g of CMC.

[0041] After cleaning, the supercapacitors prepared in Examples 1 and 2 were left to stand for 30 days. The leakage situation is shown in Table 1. Table 1, Example 2 1000pcs 30 days 10pcs 1% Example 1 1000pcs 30 days 1pcs 0.1% Analysis of the data in Table 1 shows that coating the electrode surface with a semi-solid electrolyte can significantly reduce the leakage rate of the product. This is mainly because the semi-solid electrolyte has poor fluidity, forming a protective film on the electrode surface. This also prevents the electrolyte from flowing into the casing, ensuring that it only acts inside the electrode, thus reducing leakage and improving the problem of electrolyte leakage in supercapacitors leading to product failure.

[0042] After cleaning and aging, the supercapacitors prepared in Examples 1 and 3 were subjected to reliability tests, and the high-temperature load conditions were obtained as follows. Figure 2 As shown in Table 2: Table 2, Example 2 100pcs 1000h 11pcs 11% Example 1 100pcs 1000h 1pcs 1% Through analysis Figure 2The data shows that when using the improved conductive adhesive X to manufacture supercapacitors, the internal resistance of the product can be significantly reduced, and the product lifespan can be greatly increased. Analysis of Table 2 shows that when using the improved conductive adhesive X to manufacture supercapacitors, the leakage rate of the product can be significantly reduced, improving the problem of electrolyte leakage leading to product failure. Further electrochemical performance testing of the conductive adhesive yielded conductivity data, as shown in Table 3. Table 3, Example 3 (Improved conductive adhesive) 5.06us / cm 300cp Example 1 (Improved conductive adhesive x) 177.6us / cm 1000cp Analysis of the data in Table 3 shows that the conductivity of the improved conductive adhesive is significantly increased, approximately 35 times that of the original, and the viscosity is approximately 3.3 times that of the original. The high conductivity and high viscosity reduce the internal resistance of the supercapacitor, extend its lifespan under high-temperature loads, reduce the occurrence of leakage, and improve the problem of electrolyte leakage leading to product failure in supercapacitors.

Claims

1. A method for preparing a button-type semi-solid-state supercapacitor, characterized in that, Includes the following steps, 1) Mix activated carbon, conductive agent, and binder in a certain proportion; 2) The mixture is subjected to air jet milling; 3) Roll the electrode sheet to the required thickness; 4) The rolled electrode sheets are stamped into a certain shape using a die; 5) Bake the electrode at high temperature; 6) Apply conductive adhesive X to the positive and negative electrode shells and bake; 7) Immerse the baked electrode and diaphragm in acetonitrile electrolyte, drain them, and then coat the electrode surface with a layer of semi-solid electrolyte. 8) Assemble the electrode in the following order: shell cover - electrode plate - diaphragm - electrode plate - shell cover; 9) Seal the opening; The method for preparing the semi-solid electrolyte is as follows: 1) Mix polyethylene glycol and acetonitrile electrolyte, and stir under vacuum at 10~35℃ for 1~10h to obtain mixture M; 2) Add tetraethyl orthosilicate dropwise to the mixture M from step 1, and stir under vacuum at 10~35℃ for 1~10h to obtain mixture N; 3) Add a diazoxide heterocyclic crosslinking agent to the mixture N in step 2, and stir under vacuum at 10~35℃ for 1~10h to obtain a semi-solid electrolyte; The salt in the acetonitrile electrolyte is at least one of tetraethylammonium tetrafluoroborate, methyltriethylammonium tetrafluoroborate, and 1,1-spirobispyrrolidineonium tetrafluoroborate. The conductive adhesive X is prepared from raw materials including CMC, polyolefin resin, conductive agent, and deionized water. The preparation process includes... 1) Add CMC to deionized water and stir at 10~35℃ for 1~3 hours to obtain mixture A; 2) Mix mixture A with polyolefin resin emulsion and stir under vacuum at 10~35℃ for 2~5 hours to obtain mixture B; 3) Add conductive agent to mixture B, stir at 10~35℃ for 10~50 min, and stir at 10~35℃ under vacuum for 1~3 h to obtain conductive adhesive.

2. The method for preparing the button-type semi-solid supercapacitor according to claim 1, characterized in that, In step 1), the activated carbon and conductive agent need to be dehydrated first. The dehydration temperature is 80~200℃ and the time is 1~5h. The activated carbon is one or more of YP-50F, BAC-1, DR80, and CEP21KSN. The conductive agent is one or more of Super-P, KS-15, carbon nanotubes, ECP, and acetylene black. The binder is one or more of F104, F106, and F208.

3. The method for preparing the button-type semi-solid supercapacitor according to claim 1, characterized in that, In step 2), the airflow pulverization speed is 1~2 kg / h and the pressure is 0.4~0.9 MPa. In step 3), the thickness of the electrode sheet is 0.5~1.0 mm. In step 4), the diameter of the stamped electrode sheet is 6.5~13.5 mm.

4. The method for preparing the button-type semi-solid supercapacitor according to claim 1, characterized in that, In step 5), the baking temperature of the electrode is 80~250℃, the time is 3~24h, and the vacuum degree is ≤-90Kpa. In step 6), the conductive adhesive X is coated on the inner surface of the shell cover with a thickness of 3~7μm. The baking temperature of the shell cover coated with conductive adhesive X is 60~150℃, and the time is 3~24h. In step 7), the diaphragm is baked in the same way as the shell cover in step 6). The electrode and diaphragm are immersed in the liquid for 10~30min. The semi-solid electrolyte is coated on the electrode with a thickness of 2~8μm. Steps 8) and 9) need to be completed in a drying room at a temperature of 10~35℃ and a dew point of -70~-20℃.

5. The method for preparing a semi-solid electrolyte for capacitors according to claim 1, characterized in that, The mass ratio of polyethylene glycol to acetonitrile electrolyte is 0.1~0.3:1; the mass ratio of N in the mixture to bis(diazo) heterocyclic crosslinking agent is 10~100:1; and the number average molecular weight of polyethylene glycol is 10000~18000.

6. The method for preparing the button-type semi-solid-state supercapacitor according to claim 1, characterized in that, The mass ratio of deionized water to CMC is 50~200:1, the mass ratio of mixture A to polyolefin resin emulsion is 1:10~100, and the mass ratio of mixture B to conductive agent is 5~30:

1.

7. The method for preparing a button-type semi-solid-state supercapacitor according to claim 1, characterized in that, The surface of the cover is free of rust, oil stains, plastic burrs, and gaps.

Images