Fiber-like supercapacitor preparation method and device, and fiber-like supercapacitor

Abstract

The application belongs to the technical field of supercapacitors, and relates to a preparation method of a fibrous supercapacitor, which comprises the following steps: using blended threads of stainless steel fibers and cotton fibers as positive electrode current collectors and negative electrode current collectors; using a dip-coating pulling device to dip-coat positive electrode active materials on the positive electrode current collectors in sequence to obtain positive electrodes with meter-level fibrous structures; using a chemical oxidation polymerization device to chemically oxidize and polymerize negative electrode active materials on the negative electrode current collectors to obtain negative electrodes with meter-level fibrous structures; and winding the positive electrodes and the negative electrodes on each other to form a meter-level fibrous supercapacitor. The dip-coating pulling device provided by the application is suitable for coating active materials on fibrous current collectors with a meter-level length, and a chemical oxidation polymerization device is provided, which is suitable for polymerizing active materials on fibrous current collectors with a meter-level length, and a continuous fibrous single electrode with a meter-level length is prepared, so that the length of a centimeter-level supercapacitor is improved to a meter level.

Description

Technical Field

[0001] This invention belongs to the field of supercapacitor technology and relates to a meter-scale fibrous supercapacitor. Specifically, it includes a method for preparing a meter-scale fibrous supercapacitor, a dip-coating and pulling device and a chemical oxidation polymerization device for preparing a meter-scale fibrous supercapacitor, and a meter-scale fibrous supercapacitor. Background Technology

[0002] One-dimensional linear supercapacitors have advantages such as high power density, long cycle life and fast charge and discharge speed, while also exhibiting higher weavability and flexibility, and have broad application prospects in the field of wearable electronic devices.

[0003] Typically, one-dimensional linear supercapacitors use fibrous conductive materials such as metal wires (e.g., copper, nickel, stainless steel) and carbon fibers (e.g., carbon fiber, carbon nanotube fiber) as current collectors. These current collectors offer advantages such as small size and good conductivity, but they are often expensive, increasing the manufacturing cost of linear supercapacitors and hindering large-scale production. In contrast, natural fibers, such as cotton fibers, not only have better flexibility and strong weaving ability, but are also readily available and inexpensive. However, as an insulator, cotton fibers require complex and demanding conductive treatment processes, making it difficult to use them as current collectors for the large-scale fabrication of one-dimensional linear supercapacitors.

[0004] Yarn spun from a blend of stainless steel fiber and cotton fiber (SS / Cotton) is inexpensive, highly flexible, and has good conductivity, making it suitable for large-scale fabrication of one-dimensional linear supercapacitors using this yarn as the current collector.

[0005] Zhang et al. used SS / Cotton as the current collector and electrochemically polymerized polypyrrole (PPy) onto the surface of SS / Cotton in a mixed solution of 0.1M pyrrole solution and 0.3M p-toluenesulfonic acid solution to obtain SS / Cotton-PPy electrodes. Two parallel SS / Cotton-PPy electrodes were assembled into a side-by-side asymmetric one-dimensional linear supercapacitor. [Zhang C, Chen Z, Rao W, et al. A high-performance all-solid-state yarn supercapacitor based on polypyrrole-coated stainless steel / cotton blended yarns[J]. Cellulose, 2018, 26.].

[0006] Ma et al. also used SS / Cotton as the current collector, impregnated it with a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) solution (Poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonate), PEDOT:PSS), and electrochemically polymerized PPy to obtain an SS / Cotton@PEDOT:PSS-PPy electrode. The two electrodes were then wound together to obtain a wound asymmetric one-dimensional linear supercapacitor.

[0007] [MaY,WangQ,LiangX,etal.Wearablesupercapacitorsbasedonconductivecottonyarns[J].Journalof MaterialsScience,2018,53(20).].

[0008] The supercapacitors prepared by the two studies using SS / Cotton as current collectors exhibited good electrochemical performance. However, due to limitations in dip coating and electrochemical oxidation polymerization techniques, the blended yarn longer than one meter could not form a uniform coating during dip coating, affecting the conductivity of the positive electrode. At the same time, during electrochemical polymerization, the blended yarn longer than one meter could not polymerize a uniform and effective electrode material. Therefore, the longest length of the supercapacitors prepared was only 6.5 cm, which could only be initially implanted into the fabric and could not yet realize the preparation of large-area energy storage fabrics.

[0009] In summary, the relatively short length of current one-dimensional linear flexible supercapacitors makes it difficult to meet the weaving requirements of wearable applications, thus limiting the practical application of such supercapacitors. Therefore, there is an urgent need for a method and equipment capable of fabricating meter-scale fibrous supercapacitors. Summary of the Invention

[0010] The purpose of this invention is to provide a method, apparatus, and fibrous supercapacitor for fabricating a fibrous supercapacitor, thereby addressing the problem mentioned in the background art that the current one-dimensional linear flexible supercapacitors have a relatively short length, which cannot meet the weaving requirements of wearable applications and limits the practical application of supercapacitors.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] This invention provides a method for preparing a fibrous supercapacitor, comprising the following steps:

[0013] A blend of stainless steel fiber and cotton fiber is used as a current collector, serving as the positive current collector and the negative current collector, respectively.

[0014] A positive electrode active material is sequentially dip-coated onto a positive electrode current collector using a dip-coating and pulling device to obtain a positive electrode with a meter-scale fibrous structure.

[0015] A negative electrode active material with a meter-scale fibrous structure was obtained by chemically oxidizing and polymerizing the negative electrode current collector using a chemical oxidation polymerization device.

[0016] The positive electrode prepared by the gel electrolyte encapsulation step and the negative electrode prepared by the gel electrolyte encapsulation step are intertwined, and the gel electrolyte-encapsulated positive and negative electrodes are wrapped together to form a meter-scale fibrous supercapacitor.

[0017] This invention provides a dip-coating and lifting device for sequentially dip-coating positive electrode active material onto a positive electrode current collector in the above method steps to obtain a positive electrode with a meter-scale fibrous structure.

[0018] The device includes a dip-coating support, a wire fixing unit, a dip-coating unit, and a driving mechanism. The wire fixing unit is mounted on the dip-coating support and is used to fix the positive electrode current collector on the dip-coating support. The positive electrode active material is disposed inside the dip-coating unit. The dip-coating unit is mounted on the driving mechanism. The working part of the dip-coating unit is in contact with the positive electrode current collector. The driving mechanism drives the dip-coating unit to reciprocate along the dip-coating support to dip-coat the positive electrode current collector.

[0019] Furthermore, the dip-coating support is arranged vertically, and the wire fixing unit includes a wire clamp and a wire bottom counterweight. The wire clamp is arranged on the top of the dip-coating support, and the wire clamp holds one end of the positive current collector. The wire bottom counterweight is suspended at the other end of the positive current collector.

[0020] Furthermore, the dip-coating unit includes a slurry cup and a cup holder. The cup holder is mounted on a drive mechanism. The positive electrode active material is placed inside the slurry cup. Corresponding through holes are provided at both ends of the slurry cup. The positive electrode current collector passes through the through holes on the slurry cup, and the slurry cup moves along the positive electrode current collector.

[0021] Furthermore, the top of the dip coating bracket is provided with multiple wire clamps, the bottom of the dip coating bracket is provided with multiple corresponding wire bottom counterweights, and the cup holder is provided with multiple slurry cups, the positions of the multiple slurry cups corresponding to the positions of the wire clamps.

[0022] Furthermore, the driving mechanism includes a lead screw, a slide table, and a slide table drive motor. The lead screw is arranged parallel to the dip coating bracket, the slide table slides on the lead screw, and the cup holder is arranged on the slide table. The slide table drive motor is electrically connected to the lead screw.

[0023] This invention provides a chemical oxidation polymerization apparatus for chemically oxidizing and polymerizing a negative electrode active material on a negative electrode current collector in the above method steps to obtain a negative electrode with a meter-scale fibrous structure.

[0024] The device includes a polymerization device base, which is provided with an X-axis support, a Y-axis support, and a Z-axis support, forming a three-axis motion support. A wire take-up and release assembly is provided on the X-axis support for fixing the negative electrode current collector. The wire take-up and release assembly is provided with a wire polymerization zone. A solution pool is provided on the Y-axis support. The wire polymerization zone moves relative to the solution pool in the X, Y, and Z axis directions.

[0025] Furthermore, the wire feeding and take-up assembly includes a wire feeder and a wire take-up device, which are disposed opposite to each other at both ends of the X-axis bracket, and the area between the wire feeder and the wire take-up device is a wire aggregation zone.

[0026] Furthermore, the solution pool includes a deionized water zone, a pyrrole monomer solution zone, and a FeCl solution zone arranged in parallel.

[0027] The present invention also provides a fibrous supercapacitor, which is prepared according to the above-described method for preparing a fibrous supercapacitor, wherein the length of the fibrous supercapacitor is on the order of meters.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes a method and apparatus for preparing meter-scale supercapacitors using stainless steel / cotton fiber blended yarn as positive and negative current collectors, thereby preparing a one-dimensional linear supercapacitor with a length of meter.

[0029] 1. In this invention, both the positive and negative electrodes are current collectors made of a blended yarn of stainless steel fiber and cotton fiber. The positive electrode active material includes multi-walled carbon nanotubes and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate). The positive electrode active material is sequentially dipped onto the positive electrode current collector using a dip-coating and lifting device to form a multi-walled carbon nanotube layer and a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate). The negative electrode active material includes a polypyrrole layer formed by the polymerization of pyrrole monomers. The pyrrole monomers are grown and polymerized on the negative electrode current collector using a chemical oxidation polymerization device to obtain a negative electrode after oxidative polymerization of polypyrrole.

[0030] Compared to one-dimensional linear supercapacitor fabrication methods based on other fibrous materials, this invention enables the formation of a uniform and effective active material layer on the positive and negative electrode current collectors through a dip-coating lifting device and a chemical oxidation polymerization device. This breaks through the length limitation of linear supercapacitors, increasing the length of linear devices from the centimeter level to the meter level. It solves the problem that the current one-dimensional linear flexible supercapacitors are too short to meet the weaving requirements of wearable scenarios, thus limiting the practical application of supercapacitors.

[0031] 2. The dip-coating and pulling device provided by the present invention is suitable for coating positive electrode active materials on fibrous positive electrode current collectors with a length of meter. At the same time, a chemical oxidation polymerization device is provided, which is suitable for oxidative polymerization of negative electrode active materials on fibrous current collectors with a length of meter. Compared with the preparation of electrodes by electrochemical methods, it can prepare continuous fibrous single electrodes with a length of meter. At the same time, the dip-coating and pulling device can coat the single electrode with gel electrolyte for the assembly of one-dimensional linear devices with a length of meter. Attached Figure Description

[0032] Figure 1 This is a front view of the dip-coating lifting device;

[0033] Figure 2 This is a side view of the dip-coating lifting device;

[0034] Figure 3 This is a schematic diagram of a chemical oxidation polymerization apparatus;

[0035] Figure 4 This is a front view of the chemical oxidation polymerization apparatus;

[0036] Figure 5 This is a side view of a chemical oxidation polymerization apparatus;

[0037] Figure 6 This is a top view of a chemical oxidation polymerization apparatus;

[0038] Figure 7 This is a flowchart of the method steps of the present invention;

[0039] Figure 8 This is a reference diagram for the oxidative polymerization process;

[0040] Among them, 101-base of the dip coating device, 102-dip coating bracket, 103-wire clamp, 104-weight, 105-lead screw, 106-slide table, 107-slurry cup, 108-cup holder, 109-lead screw support plate, 1010-slide table drive motor, 11-current collector;

[0041] 201-Gathering device base, 202-X-axis support, 203-Wire feeder, 204-First fixed pulley, 205-Second fixed pulley, 206-Wire take-up device, 207-X-axis motor, 208-Y-axis support, 209-Solution tank, 210-Y-axis motor, 211-Y-axis lead screw, 212-Z-axis support, 213-Z-axis lead screw, 214-Z-axis motor. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0043] Example 1

[0044] Please see Figure 1 and Figure 2 As shown, the present invention provides a dip-coating lifting device, including a wire fixing unit, a dip-coating unit, and a driving mechanism. The wire fixing unit is used to clamp the positive current collector. The driving mechanism is arranged parallel to the dip-coating support 102. The dip-coating unit is disposed on the driving mechanism and extends to the positive current collector of the wire fixing unit. The dip-coating unit contacts the positive current collector. The driving mechanism drives the dip-coating unit to reciprocate along the dip-coating support 102, thereby dip-coating the positive current collector.

[0045] The dip coating holder 102 is made of 4040 aluminum, and the dip coating device base 101 is installed at the bottom of the dip coating holder 102.

[0046] The dip coating unit includes a slurry cup 107 and a cup holder 108. The cup holder 108 is mounted on the drive mechanism. The top and bottom of the slurry cup 107 are provided with corresponding through holes. The positive current collector passes through the through holes on the slurry cup 107. The slurry cup 107 contains the liquid to be dip coated. The drive mechanism drives the slurry cup 107 to move along the positive current collector to dip coat the blended yarn.

[0047] The drive mechanism is preferably a linear motion mechanism, which includes a ball screw pair consisting of a lead screw 105 and a slide 106. The lead screw 105 is mounted on a lead screw support plate 109, which is parallel to the dip coating bracket 102. The slide 106 slides on the lead screw 105, and the cup holder 108 is mounted on the slide 106. The linear motion mechanism also includes a slide drive motor 1010, which is electrically connected to the lead screw 105. The slide drive motor 1010 facilitates stroke and speed control using a controller.

[0048] The cable fixing unit includes two installation methods:

[0049] Firstly, the dip-coating bracket 102 is set horizontally or vertically, and the wire fixing unit includes the dip-coating bracket 102 and the wire clamp 103. The wire clamp 103 is set at both ends of the dip-coating bracket 102, and the positive current collector is clamped between the wire clamps 103.

[0050] Secondly, the dip-coating bracket 102 is arranged vertically, and the wire fixing unit includes the dip-coating bracket 102, the wire clamp 103 and the bottom counterweight of the wire. The wire clamp 103 is arranged on the top of the dip-coating bracket 102, and the wire clamp 103 clamps one end of the positive current collector, while the bottom counterweight of the wire is suspended at the other end of the positive current collector.

[0051] To further optimize, when the dip coating bracket 102 is placed horizontally, multiple corresponding wire clamps 103 are provided at both ends of the dip coating bracket 102.

[0052] In this embodiment, the dip coating support 102 is preferably placed vertically. Multiple wire clamps 103 are provided on the top of the dip coating support 102, and multiple corresponding wire bottom weights are provided on the bottom of the dip coating support 102. Compared with the wire clamps 103, the wire bottom weights can keep the blended yarn taut during the dip coating process under the action of gravity, so as to uniformly dip the blended yarn and make the operation simple. The wire bottom weights can preferably be weights 104. Multiple slurry cups 107 are provided on the cup holder 108. The positions of the multiple slurry cups 107 correspond to the positions of the wire clamps 103 on the top of the dip coating support 102, so that multiple current collectors can be dip coated at the same time.

[0053] Example 2

[0054] Please see Figures 3 to 6 As shown, the present invention provides a chemical oxidation polymerization apparatus, including a polymerization apparatus base 201. The polymerization apparatus base 201 is provided with an X-axis support 202, a Y-axis support 208, and a Z-axis support 212, which form a three-axis motion support. A wire take-up and release assembly is provided on the X-axis support 202 for fixing the negative electrode current collector. A wire polymerization zone is provided between the wire take-up and release assemblies. A solution pool 209 is provided on the Y-axis support 208. The wire polymerization zone moves relative to the solution pool in the X, Y, and Z axis directions, so that the wire polymerization zone extends into the solution pool to carry out the oxidation polymerization reaction.

[0055] The wire feeding and take-up assembly includes a wire feeder 203 and a wire take-up 206, which are arranged opposite each other at both ends of the X-axis bracket 202. The area between the wire feeder 203 and the wire take-up 206 is the wire aggregation area.

[0056] An X-axis motor 207 is mounted on the X-axis bracket 202, and the X-axis motor 207 is electrically connected to the take-up device 206.

[0057] The wire take-up and unwinding assembly includes a guide pulley group, which is set in the wire aggregation area. The guide pulley group includes a first fixed pulley 204 and a second fixed pulley 205. The first fixed pulley 204 is set near the wire feeder 203, and the second fixed pulley 205 is set near the wire take-up unit 206.

[0058] A Y-axis lead screw 211 is installed on the Y-axis support 208. The solution pool 209 and the Y-axis lead screw 211 form a ball screw pair. The solution pool 1 moves linearly along the Y-axis lead screw 211.

[0059] Solution tank 209 is equipped with three solution zones: a deionized water zone, a pyrrole monomer solution zone, and a FeCl3 solution zone, which are arranged side by side.

[0060] Z-axis support 212 is equipped with Z-axis lead screw 213, X-axis support 202 is fixed to Z-axis lead screw 213, and a ball screw pair is formed between X-axis support 202 and Z-axis lead screw 213. X-axis support 202 moves linearly along Z-axis lead screw 213.

[0061] The Y-axis lead screw 211 is driven by the Y-axis motor 210, and the Z-axis lead screw 213 is driven by the Z-axis motor 214. At the same time, a controller is set up to control the stroke of the Y-axis motor 210 and the Z-axis motor 214. Simultaneously, the controller controls the X-axis motor 207 to enable the take-up device 206 to automatically take up the wire.

[0062] Please see Figure 7 The principle of chemical oxidative polymerization is that FeCl3 oxidizes pyrrole monomers, causing them to polymerize and gradually form dipyrrole, tripyrrole, and finally polypyrrole chains. The chemical oxidative polymerization apparatus of this invention is based on the principle of oxidative polymerization. First, the blended yarn is soaked in a solution that absorbs pyrrole monomers, and then immersed in a FeCl3 solution to undergo an oxidative polymerization reaction to generate polypyrrole. Excess ferric chloride solution is then removed in deionized water. This is a single-pass process. The above process is repeated until the polypyrrole material reaches the required basis weight at the negative electrode, thus completing the polymerization of the negative electrode material.

[0063] In use, the wire to be polymerized is placed across the wire polymerization zone formed by the wire feeder 203 and the take-up device 206, and the controller is activated. First, the Y-axis motor 210 is controlled to move the pyrrole monomer solution zone in the solution tank directly below the wire polymerization zone of the X-axis support. Then, the Z-axis motor 214 is controlled to move the X-axis support 202 downward along the Z-axis screw 213, immersing the wire to be polymerized into the pyrrole monomer solution zone. After the wire has fully absorbed the pyrrole monomer solution (approximately 30 seconds), the X-axis support 202 moves upward to remove the wire from the pyrrole monomer solution zone. Next, the Y-axis motor 210 is controlled to move the FeCl3 solution zone directly below the wire polymerization zone. Similarly, the X-axis support 202 moves downward to immerse the wire into the FeCl3 solution zone. After the polymerization reaction is complete (approximately 2 minutes), the X-axis support 202 moves upward to remove the wire from the FeCl3 solution zone. In the l3 solution zone, the Y-axis motor 210 is controlled to move the deionized water zone to below the wire polymerization zone, causing the X-axis support 202 to move downwards and repeatedly immerse the wire in the deionized water to wash away excess FeCl3 solution. This is the workflow for a single oxidation polymerization reaction. According to the design basis weight of the negative electrode polymerization material, the pyrrole monomer solution zone of the Y-axis support 208 needs to be moved back to directly below the wire polymerization zone of the X-axis support 202. The above workflow is repeated. After the last cleaning in the last cycle, the Y-axis and Z-axis return to their initial positions, and the X-axis motor 207 controls the take-up device 206 to rotate, collecting the polymerized wire segments and sending the wire to be polymerized to the reaction zone. The next cycle of the workflow is then performed until the reaction in the area of ​​the wire to be polymerized is completed, resulting in a supercapacitor negative electrode that meets the design requirements.

[0064] Example 3

[0065] Please see Figure 7 As shown, a method for fabricating a fibrous supercapacitor includes the following steps:

[0066] (1) Stainless steel fiber and cotton fiber are made into a blended yarn and used as current collector 11, which are respectively used as positive current collector and negative current collector;

[0067] (2) Using the above-mentioned dip-coating and lifting device, positive electrode active material is sequentially dip-coated onto the positive electrode current collector to obtain a fibrous positive electrode;

[0068] (3) Using the above-mentioned chemical oxidation polymerization device, the negative electrode active material is chemically oxidized and polymerized on the negative electrode current collector to obtain a fibrous negative electrode;

[0069] (4) The positive electrode obtained in step (2) is wrapped with gel electrolyte, and the negative electrode in step (3) is wrapped with gel electrolyte. The positive electrode wrapped with gel electrolyte and the negative electrode wrapped with gel electrolyte are intertwined, and the gel electrolyte is wrapped on the intertwined positive and negative electrodes to form a fibrous supercapacitor.

[0070] The aforementioned positive electrode includes a positive electrode current collector and a positive electrode active material. Specifically, the positive electrode current collector is a blended yarn made of stainless steel fiber and cotton fiber, and the positive electrode active material includes multi-walled carbon nanotubes (MWCNTs) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) solution (PEDOT:PSS). Specifically, a multi-walled carbon nanotube layer and a (3,4-ethylenedioxythiophene):poly(styrenesulfonate) layer are sequentially impregnated onto the blended yarn of the positive electrode current collector to form a fibrous positive electrode structure.

[0071] The aforementioned negative electrode includes a negative electrode current collector and a negative electrode active material. The negative electrode current collector is also a blended yarn made of stainless steel fiber and cotton fiber (Stainless Steel / Cotton, SS / Cotton); the negative electrode active material includes polypyrrole (PPy). Please refer to [link to relevant documentation]. Figure 8 Polypyrrole (PPy) is grown on a stainless steel / cotton blended yarn (SS / Cotton) that serves as the negative electrode current collector through a chemical oxidative polymerization reaction, forming a fibrous negative electrode.

[0072] Both the positive and negative electrodes with the aforementioned fibrous structure are coated with gel electrolyte. The positive and negative electrodes coated with gel electrolyte are then intertwined, and the gel electrolyte then encapsulates the intertwined positive and negative electrodes as a whole, forming a fibrous supercapacitor.

[0073] Gel electrolytes are gel electrolytes with polyvinyl alcohol as a binder. After solidification, gel electrolytes act as diaphragms and ion transport media.

[0074] Example 4

[0075] A fibrous supercapacitor is prepared using the above-described method, specifically including the following steps:

[0076] (1) Stainless steel fiber and cotton fiber are made into a blended yarn and used as current collector 11, which are respectively used as positive current collector and negative current collector;

[0077] (2) Using the above-mentioned dip-coating and pulling device, the positive electrode active material is sequentially dip-coated onto the positive electrode current collector to obtain a fibrous positive electrode;

[0078] (3) Using the above-mentioned chemical oxidation polymerization device, the negative electrode active material is chemically oxidized and polymerized on the negative electrode current collector to obtain a fibrous negative electrode;

[0079] (4) The positive electrode obtained in step (2) is wrapped with gel electrolyte, and the negative electrode in step (3) is wrapped with gel electrolyte. The positive electrode wrapped with gel electrolyte and the negative electrode wrapped with gel electrolyte are intertwined, and the gel electrolyte is wrapped on the intertwined positive and negative electrodes to form a fibrous supercapacitor.

[0080] In step (2), the positive electrode active material is sequentially dipped into the positive electrode current collector to obtain a fibrous positive electrode, specifically as follows:

[0081] The positive electrode active material is a multi-walled carbon nanotube layer and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate).

[0082] Multi-walled carbon nanotubes are black powdery particles with a particle size of 0–500 μm; poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) is a dark blue liquid.

[0083] First, multi-walled carbon nanotubes are prepared into a multi-walled carbon nanotube dispersion, and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) is prepared into a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution.

[0084] Subsequently, a multi-walled carbon nanotube dispersion and a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution were sequentially dipped into the positive electrode current collector to obtain a fibrous positive electrode structure consisting of a positive electrode current collector, a multi-walled carbon nanotube layer, and a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) layer from the inside out.

[0085] The above preparation method for multi-walled carbon nanotube dispersions:

[0086] A 10 g / L sodium dodecylbenzenesulfonate aqueous solution was prepared. Sodium dodecylbenzenesulfonate, as a surfactant, helps disperse multi-walled carbon nanotubes (MWCNTs) in water. MWCNT powder was gradually added until the concentration of the MWCNT dispersion was 1.5 g / L. The prepared MWCNT dispersion was then sonicated for 1 hour using a cell sonicator to obtain a uniformly dispersed MWCNT dispersion.

[0087] The preparation method of the above poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution is as follows:

[0088] A 1.2wt%-1.5wt% aqueous solution of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) and a 5% or 7% (v / v) volume ratio ethylene glycol solution are mixed and stirred until homogeneous to obtain a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution. The concentration of ethylene glycol is ≥99.5%, and the ethylene glycol is used to further improve the conductivity of the solution.

[0089] The above-mentioned dip coating methods include:

[0090] 1) Cleaning the blended yarn: Cut the blended yarn to the required length, soak it in 75% ethanol solution to wash away surface impurities, take it out after 15 minutes, rinse it with deionized water to further remove impurities, then soak it in 6M sulfuric acid solution for 10 minutes to remove the oxide layer on the surface of the blended yarn to improve the conductivity of the blended yarn, take it out and rinse it repeatedly with deionized water until neutral, and let it air dry naturally.

[0091] 2) Dip-coating multi-walled carbon nanotube dispersion: Using the above-mentioned dip-coating lifting device, such as... Figure 1 , 2 As shown, the cleaned blended yarn is uniformly dipped and coated. Specifically, one end of the blended yarn is fixed to the yarn clamp at the top of the dip coating lifting device, and the other end of the blended yarn is passed through the hole at the bottom of the slurry cup. A weight is then attached to the bottom of the blended yarn. The weight serves as a counterweight at the bottom of the yarn to ensure that the blended yarn remains taut during the dip coating process, which is conducive to the uniform coating of the slurry. Then, the slurry to be dipped is loaded into the slurry cup for dip coating.

[0092] 3) After a single dip coating of multi-walled carbon nanotubes, place the tubes in an 80°C oven and dry for 20 minutes. Then remove the tubes and repeat the above dip coating and drying steps until the required weight of the multi-walled carbon nanotube layer is achieved, thus completing the dip coating of multi-walled carbon nanotubes.

[0093] 4) Dip-coating with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution: Dip-coat the blended yarn that has been dip-coated with multi-walled carbon nanotubes with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution. After a single dip-coating, place it in an 80°C oven to dry for 20 minutes and then remove it. Repeat the above dip-coating and drying steps to achieve the required basis weight of the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) layer, thus completing the dip-coating with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution.

[0094] In step (3) above, the negative electrode active material is chemically oxidized and polymerized on the negative electrode current collector to obtain a fibrous negative electrode, specifically as follows:

[0095] 1) Cleaning the blended yarn: Cut the blended yarn to the required length, soak it in 75% ethanol solution for 15 minutes to wash away surface impurities, take it out, wipe the blended yarn repeatedly with ethanol-soaked paper, rinse with deionized water to further remove impurities, then soak it in 6M sulfuric acid solution for 10 minutes to remove the oxide layer on the surface of the blended yarn, take it out and rinse it repeatedly with deionized water until neutral, and let it air dry naturally.

[0096] 2) Preparation of pyrrole monomer solution: Prepare a 0.2M NaClO4 solution, then add pyrrole monomer solution equivalent to 6% of the NaClO4 solution by volume, and stir on a magnetic stirrer until there are no obvious liquid droplets in the solution.

[0097] 3) Preparation of oxidant solution: Prepare 0.3M-0.9M FeCl3 solution.

[0098] 4) For the chemical oxidation polymerization apparatus described above, please refer to [link / reference needed]. Figures 3 to 6 The blended yarn was immersed in a pyrrole monomer solution for 30 seconds, and then immediately placed in a FeCl3 solution for 2 minutes (FeCl3 was used as an oxidant to oxidize and polymerize the pyrrole monomer). Then, the excess solution was rinsed off with deionized water. The above steps of immersion, reaction and rinsing were repeated to obtain the negative electrode after oxidative polymerization of polypyrrole, which was then air-dried.

[0099] Step (4) also includes the following steps:

[0100] 41) Preparation of gel electrolyte: First, dissolve polyvinyl alcohol in deionized water at 70-90℃. After the solution cools to room temperature, add electrolyte to obtain the gel electrolyte of the required concentration. Specifically, weigh a certain mass of polyvinyl alcohol (PVA) solid and add it to deionized water at 70-90℃ (the solid-liquid ratio of PVA to deionized water is 1:10). Stir with a magnetic stirrer until there are no obvious particles. After the solution cools to room temperature, add phosphoric acid solid to obtain the gel electrolyte of the required concentration.

[0101] 42) Dip the positive and negative electrodes with the gel electrolyte prepared in step 41) above. After dipping, dry with a hot air gun at 100°C for 2 minutes to facilitate the subsequent winding of the positive and negative electrodes.

[0102] 43) Wrap the positive and negative electrodes together, then immerse the whole assembly in the gel electrolyte for 5 minutes. After removing it, dry it with a 100°C hot air gun for 5 minutes to obtain a fibrous supercapacitor. Specifically, wrap the two fibrous electrodes obtained in step 42) together with a length ratio of 1:1 or 2.5:1 between the positive and negative electrodes. After completing the wrapping, immerse the positive and negative electrodes together in the gel electrolyte for 2 minutes, then remove them and dry them with a 100°C hot air gun for 5 minutes to obtain a meter-sized fibrous supercapacitor.

[0103] In this embodiment, a positive electrode with a length of 1m and a negative electrode with a length of 1m were prepared. The positive and negative electrodes were immersed in the gel electrolyte for 2 minutes and then removed and dried with a hot air gun. The dried negative electrode was evenly wound around the positive electrode. After the winding was completed, the positive and negative electrodes were immersed in the gel electrolyte for 2 minutes and then removed and dried with a hot air gun to obtain a 1m long wound fibrous asymmetric supercapacitor.

[0104] Compared to other one-dimensional linear asymmetric supercapacitors that use stainless steel fiber and cotton fiber blended yarn (SS / Cotton) as current collectors, this invention grows different active materials on the positive and negative current collectors, prepares positive and negative electrodes with complementary voltage windows, and constructs a supercapacitor with a widened voltage window.

[0105] In summary, the dip-coating lifting device provided by this invention is suitable for coating active materials onto fibrous current collectors with lengths in the meter range. Simultaneously, a chemical oxidation polymerization device is provided, suitable for polymerizing active materials onto fibrous current collectors with lengths in the meter range, to prepare continuous fibrous single electrodes with lengths in the meter range. This overcomes the limitations of dip-coating technology and electrochemical oxidation polymerization technology, enabling the length of centimeter-electrode supercapacitors to be increased to the meter range. It solves the problem that existing one-dimensional linear flexible supercapacitors have relatively short lengths, failing to meet the weaving requirements of wearable applications, and limiting the practical application of supercapacitors.

Claims

1. A method for fabricating a fibrous supercapacitor, characterized in that, Includes the following steps: (1) A blended yarn of stainless steel fiber and cotton fiber is used as a current collector (11), which is the positive current collector and the negative current collector, respectively; (2) The positive electrode active material is sequentially dipped onto the positive electrode current collector using a dip-coating and pulling device to obtain a positive electrode with a meter-scale fibrous structure; the positive electrode active material includes multi-walled carbon nanotubes and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution. (3) The negative electrode active material is chemically oxidized and polymerized on the negative electrode current collector using a chemical oxidation polymerization device to obtain a negative electrode with a meter-scale fibrous structure; the negative electrode active material includes polypyrrole; (4) The positive electrode obtained in step (2) is wrapped with gel electrolyte, and the negative electrode in step (3) is wrapped with gel electrolyte. The positive electrode wrapped with gel electrolyte and the negative electrode wrapped with gel electrolyte are intertwined. The gel electrolyte is wrapped on the intertwined positive and negative electrodes to form a meter-scale fibrous supercapacitor. The gel electrolyte is a gel electrolyte with polyvinyl alcohol as a binder.

2. A dip-coating lifting device, characterized in that, The method for preparing the fibrous supercapacitor according to claim 1 includes: The device comprises a dip-coating support (102), a wire fixing unit, a dip-coating unit, and a driving mechanism. The wire fixing unit is disposed on the dip-coating support (102) and is used to fix the positive current collector on the dip-coating support (102). The positive active material is placed inside the dip-coating unit. The dip-coating unit is disposed on the driving mechanism. The working part of the dip-coating unit is in contact with the positive current collector. The driving mechanism drives the dip-coating unit to reciprocate along the dip-coating support (102) to dip-coat the positive current collector.

3. The dip-coating lifting device according to claim 2, characterized in that, The dip-coating support (102) is arranged vertically. The wire fixing unit includes a wire clamp (103) and a bottom counterweight of the wire. The wire clamp (103) is arranged on the top of the dip-coating support (102). The wire clamp (103) clamps one end of the positive current collector, and the bottom counterweight of the wire is suspended at the other end of the positive current collector.

4. The dip-coating lifting device according to claim 3, characterized in that, The dip coating unit includes a slurry cup (107) and a cup holder (108). The cup holder (108) is mounted on a drive mechanism. The slurry cup (107) is placed inside the cup holder (108). The position of the slurry cup (107) corresponds to the position of the wire clamp (103). The positive electrode active material is placed inside the slurry cup (107). Corresponding through holes are provided at both ends of the slurry cup (107). The positive electrode current collector passes through the through holes on the slurry cup (107). The slurry cup (107) moves along the positive electrode current collector.

5. The dip-coating lifting device according to claim 4, characterized in that, Multiple cup holders (108) and slurry cups (107) are provided. Multiple wire clamps (103) are provided on the top of the dip coating bracket (102), and multiple corresponding wire bottom counterweights are provided on the bottom of the dip coating bracket (102).

6. The dip-coating lifting device according to claim 5, characterized in that, The driving mechanism includes a lead screw (105), a slide table (106), and a slide table drive motor (1010). The lead screw (105) is arranged parallel to the dip-coating bracket (102), the slide table (106) slides on the lead screw (105), and the cup holder (108) is arranged on the slide table (106). The slide table drive motor (1010) is electrically connected to the lead screw (105).

7. A chemical oxidation polymerization apparatus, characterized in that, The method for preparing the fibrous supercapacitor according to claim 1 includes: The polymerization device base (201) is provided with an X-axis support (202), a Y-axis support (208) and a Z-axis support (212), which form a three-axis motion support. A wire take-up and release assembly is provided on the X-axis support (202), which is used to fix the negative electrode current collector. The wire take-up and release assembly is provided with a wire polymerization area. A solution pool (209) is provided on the Y-axis support (208). The wire polymerization area moves relative to the solution pool (209) in the X-axis, Y-axis and Z-axis directions.

8. The chemical oxidation polymerization apparatus according to claim 7, characterized in that, The wire feeding and take-up assembly includes a wire feeder (203) and a wire take-up device (206). The wire feeder (203) and the wire take-up device (206) are arranged opposite to each other at both ends of the X-axis bracket (202). The area between the wire feeder (203) and the wire take-up device (206) is a wire aggregation area.

9. The chemical oxidation polymerization apparatus according to claim 8, characterized in that, The solution pool (209) includes a deionized water zone, a pyrrole monomer solution zone, and a FeCl3 solution zone arranged in parallel.

10. A fibrous supercapacitor, characterized in that, The fibrous supercapacitor is prepared according to the method described in claim 1, wherein the length of the fibrous supercapacitor is on the order of meters.

Images