A stretchable turf-like fabric electrode material and its preparation method and application

Abstract

The present application relates to the technical field of electrochemical materials, and particularly discloses a stretchable turf-like fabric electrode material, a preparation method and application thereof.The preparation method of the stretchable turf-like fabric electrode material comprises the following steps: weaving carbonized kapok fibers and cotton / spandex yarns into an integrated three-dimensional turf-like fabric through a computerized flat knitting machine weaving process, wherein the carbonized kapok fibers form conductive electrodes, and the cotton / spandex yarns serve as spacers to directly construct a three-dimensional stretchable electrode; and the carbonized kapok fibers are treated in a special way to have moderate toughness, high spinnability, and form fluff on the surface during weaving, which is integrated with the fabric base, so that the problem of being not firm and easy to fall off does not exist, and the operation is simple, and the preparation cost can be greatly reduced to realize one-step construction of a stretchable three-dimensional flexible electrode with a self-supporting structure, and the method has great industrial application value.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical materials, and in particular to a stretchable turf-like fabric electrode material, a preparation method thereof, and applications thereof. Background Art

[0002] With the miniaturization and flexibility of electronic products and the advancement of textile technology, electronic smart textiles, as the most widely developed and applied smart textiles, are continuously enriching product categories and broadening their application areas. They are gradually gaining acceptance by the market and consumers, becoming one of the key development directions for the future of textiles and apparel. New wearable electronic devices will be integrated into smart clothing systems, which will include input devices such as sensors to detect biometric data and output devices (such as light-emitting displays) to display data to the user. How to provide power for the next generation of smart clothing to ensure the continuous functioning of these wearable devices will be a major research focus in the future.

[0003] Currently, wearable electronic devices primarily rely on bulky "black box" battery packs that fail to meet comfort and wearability requirements. Therefore, developing lightweight, stretchable energy storage devices that can be seamlessly integrated with textiles is a key technical challenge in the development of wearable devices. Microsupercapacitors (MSCs) offer advantages such as controllable volume, diverse structures, high charge / discharge efficiency, long cycle life, and ease of integration, making them one of the most promising energy sources. The redox reaction in a microsupercapacitor primarily occurs between two adjacent interdigitated electrodes, and the number of reaction sites depends largely on the height of the electrode cross-section. Three-dimensional microsupercapacitors, by increasing electrode thickness, create more reaction sites. Larger specific surface areas and faster electron transfer rates can improve the areal capacitance of microsupercapacitors. Stretch textile substrates offer inherent stretchability, bendability, foldability, ease of integration, and washability and friction resistance, which are unmatched by other sheet materials. The MSCs themselves can serve as both electrode carriers and integrated platforms for wearable energy storage.

[0004] At present, the methods for preparing fabric-based three-dimensional flexible electrodes mainly include hydrothermal growth, chemical deposition, electrodeposition, in-situ polymerization, magnetron sputtering and electrostatic flocking. However, most of the above methods require the use of special equipment for complex processing. Moreover, since the three-dimensional structure is formed by special methods and is not directly integrated with the fabric base, it is not firm, which limits its large-scale application. Summary of the Invention

[0005] In response to the problems of existing micro supercapacitors such as high electrode preparation cost, limited stretchability, and weak three-dimensional partial load that is easy to fall off, the present invention provides a stretchable turf-like fabric electrode material, its preparation method and application.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] A method for preparing a stretchable turf-like fabric electrode material, characterized by comprising the following steps:

[0008] Step a, soaking kapok fibers in a strong alkaline solution, washing, and drying to obtain alkali-treated kapok fibers;

[0009] Step b, adding the alkali-treated kapok fiber and sodium hypophosphite into water, immersing, and drying to obtain salt-treated kapok fiber;

[0010] Step c, subjecting the salt-treated kapok fiber to low-temperature oxidation at 180-200° C. in an air atmosphere, and then subjecting it to high-temperature calcination at 650-700° C. in an inert atmosphere, cooling it, and impregnating it in a strong acid solution to obtain carbon fiber;

[0011] Step d, adding the carbon fiber to an aqueous solution of a polyoxyethylene ether surfactant, immersing at 90-100° C., washing with water, and drying to obtain pretreated carbon fiber;

[0012] Step e: Weaving the pretreated carbon fiber and cotton / spandex yarn in a preset conductive area and insulating area using a computerized flat knitting machine to obtain a stretchable turf-like fabric electrode material.

[0013] Compared with the prior art, the preparation method of the stretchable turf-like fabric electrode material provided by the present invention uses kapok fiber as the raw material for preparing carbon fiber. The kapok fiber has a unique thin-walled large hollow structure and the excellent characteristics of light weight, which is conducive to shortening the electron transfer distance and improving the carrier efficiency. After the kapok fiber is soaked in a strong alkali and sodium hypophosphite, P doping can be achieved in the subsequent carbonization process, and the gas generated by the decomposition of sodium hypophosphite during the carbonization process can cause the carbon fiber to have multi-level pores, thereby improving its energy storage performance. The hollow carbon fiber obtained by carbonization is soaked in a polyoxyethylene ether surfactant, which can improve the spinnability of the carbon fiber, avoid the problem of winding the roller, and also make the carbon fiber have moderate toughness, so that the carbon fiber can break freely on the surface during the spinning process to form fluff, and the turf-like fabric can be directly obtained without cutting the pile.

[0014] The application provides a preparation method of a stretchable artificial turf fabric electrode material, which directly weaves carbonized kapok fibers and yarns into an integrated three-dimensional artificial turf fabric through a computerized flat knitting machine weaving process, the kapok carbon fiber part constitutes a conductive electrode, the yarn part plays a spacing role, a three-dimensional stretchable electrode is directly constructed, and the carbonized kapok fiber treated in a special way has moderate toughness, is high in spinnability, and can be freely broken on the surface to form fluff during weaving, since the fluff is integrated with the fabric base, there is no problem of being not firm and easily falling off, the operation is simple, the preparation cost can be greatly reduced, a one-step method is used to construct a self-supporting structure of a stretchable three-dimensional flexible electrode, and the method has great industrial application value.

[0015] Preferably, in step a, the strong alkali solution is a sodium hydroxide solution with a mass concentration of 2%-3%, and the immersion time is 40-50h.

[0016] Preferably, in step a, the ratio of the kapok fiber to the strong alkali solution is 1g:8-10mL.

[0017] Preferably, in step b, the mass ratio of the alkali-treated kapok fiber, sodium hypophosphite and water is 1:1.5-2.5:4-6, and the immersion time is 30-45min.

[0018] Further, in step b, the ratio of the alkali-treated kapok fiber to water is 1g:8-10mL.

[0019] Preferably, the immersion condition can realize effective doping of P in the carbon fiber, improve the active site and hydrophilicity of the carbon fiber, promote the contact and wettability of the carbon fiber and an electrolyte, fully expose the electroactive site, and promote the generation of a multi-level pore of the carbon fiber through the gas generated by the cracking of sodium hypophosphite in the subsequent carbonization process, thereby improving the energy storage performance of the carbon fiber.

[0020] Preferably, in step c, the low-temperature oxidation time is 1.5-2h.

[0021] Preferably, in step b, the temperature is raised to 400-500 DEG C in a programmed heating mode, and the heating rate is 5-10 DEG C / min.

[0022] Preferably, in step c, the temperature is raised to 180-200 DEG C in a programmed heating mode, and the heating rate is 3-5 DEG C / min.

[0023] Preferably, in step c, the temperature is raised to 650-700 DEG C in a programmed heating mode, and the heating rate is 1.5-2 DEG C / min.

[0024] Preferably, in step c, the high-temperature calcination time is 1-1.5h.

[0025] The optimized carbonization process can promote the generation of multi-level pores in carbon fibers while maintaining the hollow structure of kapok fibers, enhance the adsorption and storage capacity of the carbon fiber surface for charges in the electrolyte solution, and provide a large number of transmission channels for electron transfer; in addition, the existence of multi-level pores can also effectively buffer the changes in the volume of carbon fibers during charging and discharging.

[0026] Preferably, in step c, the strong acid solution is a 1-1.5 mol / L hydrochloric acid solution, and the immersion time is 1-1.5 h.

[0027] Furthermore, in step c, the ratio of the kapok fiber calcined at high temperature to the strong acid solution is 1 g:8-10 mL.

[0028] Preferably, in step d, the polyoxyethylene ether surfactant is at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyether or ethoxylated fatty acid sorbitan ester.

[0029] Preferably, in step d, the concentration of the polyoxyethylene ether surfactant in the aqueous solution is 15 wt%-20 wt%.

[0030] Preferably, in step d, the immersion time is 30-45 minutes.

[0031] Furthermore, in step d, the ratio of the carbon fiber to the aqueous solution of the polyoxyethylene ether surfactant is 1 g:8-10 mL.

[0032] Impregnation of carbon fibers with specific surfactants can improve their spinnability. Without any treatment, the carbon fibers are too brittle to be woven. If other surfactants, such as anionic surfactants, are used for impregnation, the electrostatic interaction between the fibers is large, which can easily cause problems such as winding and entanglement, resulting in poor spinnability and making it impossible to achieve automatic weaving on a flat knitting machine. In addition, impregnation with the above-mentioned specific surfactants can also give the carbon fibers moderate toughness. While ensuring that they can be woven on a flat knitting machine, the carbon fiber surface can also be freely broken to form fluff, achieving a one-step construction of three-dimensional flexible electrode materials.

[0033] Preferably, in step e, the specific steps of knitting by the computerized flat knitting machine are:

[0034] S1, according to the design pattern of the knitted fabric, cotton / spandex yarn is knitted in a preset insulation area on the front needle bed of a computerized flat knitting machine by plain stitch to obtain a plain stitch insulation structure;

[0035] S2, at the connection between the cotton / spandex yarn and the pretreated carbon fiber, the cotton / spandex yarn is used to weave a tuck loop at the outermost needle of the carbon fiber weaving area for connection;

[0036] S3, within a preset conductive range, knitting the pretreated carbon fiber on the front needle bed of a computerized flat knitting machine using a plain weft needle to obtain a plain weft conductive structure;

[0037] S4, repeat S2, S1, S2 in sequence;

[0038] S5, adjusting the front needle bed and the rear needle bed to be staggered within a preset conductive range, tucking the pretreated carbon fiber on the front and rear needle beds to form a long loop on the back of the plain weft stitch;

[0039] S6, repeat S2, S1, S2 in sequence;

[0040] S7, within a preset conductivity range, the pretreated carbon fiber is again weft-knitted on the front needle bed;

[0041] S8, lowering the knitting needles of the rear needle bed to break the tuck yarn of the rear needle bed in the preset conductive range;

[0042] S9, repeat S2 and S1 in sequence;

[0043] S10, repeat S2-S9 in sequence until the weaving is completed.

[0044] Further preferably, in step e, the bending depth of the weft plain needle yarn is 12.00 mm, and the bending depth of the tuck stitch yarn is 12.5 mm.

[0045] Furthermore, the cotton / spandex yarn is made of 10s pure cotton yarn and 40D spandex covered yarn, and the mass ratio of the cotton yarn to the spandex yarn is 95:5.

[0046] The preferred flat knitting process can ensure that the carbon fibers are automatically broken during the flat knitting process, and the obtained pile is of moderate length without the yarn breaking, thereby ensuring that the prepared fabric is dense, uniform in thickness, and smooth in appearance.

[0047] The present invention also provides a stretchable turf-like fabric electrode material, which is prepared by any of the above methods for preparing a stretchable turf-like fabric electrode material.

[0048] The present invention also provides application of the stretchable turf-like fabric electrode material in a supercapacitor.

[0049] The present invention also provides a supercapacitor electrode, comprising the stretchable turf-like fabric electrode material and nano-sheet copper sulfide loaded on the surface of the stretchable turf-like fabric electrode material.

[0050] The application directly weaves carbonized kapok fibers and yarns into a three-dimensional turf-like fabric through a full-automatic computerized flat knitting machine, wherein the fluff formed by free breaking of the carbonized kapok fibers is integrated with the fabric base and will not easily fall off, and the nanosheet copper sulfide is loaded on the surface of the turf-like fabric electrode material prepared above, so that the loading amount of the copper sulfide can be increased, and the copper sulfide is distributed in a layer shape on the surface of the three-dimensional fabric electrode, the pieces of copper sulfide are interconnected, a rich space structure is formed, and the energy storage performance of the electrode is significantly improved in cooperation with the carbon fibers.

[0051] The application further provides a preparation method of the supercapacitor electrode.

[0052] Step S1, soaking the stretchable turf-like fabric electrode material into an ethanol aqueous solution, washing with water, drying, and obtaining a pretreated fabric electrode material;

[0053] Step S2, taking the pretreated fabric electrode material as a working electrode, taking a saturated mercury-mercury electrode as a reference electrode, taking a copper electrode as a counter electrode, and taking a mixed solution of copper sulfate and boric acid as an electrolyte, and performing constant current deposition to obtain an electrode precursor material;

[0054] Step S3, adding the electrode precursor material and thiourea into water and uniformly mixing, hydrothermal reaction at 120-130 DEG C for 20-25 h, washing with water, and drying to obtain the supercapacitor electrode.

[0055] The preparation method of the supercapacitor electrode provided by the application is simple in operation, suitable for industrialized batch production, and has a wide application prospect.

[0056] Preferably, in step S1, the mass concentration of the ethanol aqueous solution is 25%-35%, and the soaking time is 30-45 min.

[0057] Preferably, in step S2, the concentration of copper sulfate in the electrolyte is 0.5-1.0 mol / L, and the concentration of boric acid is 0.2-0.3 mol / L.

[0058] Preferably, in step S2, the current density of the constant current deposition is 2-5 mA / cm 2 , and the time of the constant current deposition is 70-90 min.

[0059] Preferably, in step S3, the ratio of the thiourea to water is 2-3 mmol:15-20 mL.

[0060] The application further provides a supercapacitor comprising the supercapacitor electrode.

[0061] Compared with the prior art, the application has the following advantages:

[0062] (1) The present application adopts the carbonized kapok fiber and cotton / spandex yarns treated in a special way to directly weave into a three-dimensional artificial turf fabric by using a flat knitting machine, which has a natural hollow structure and a multi-level pore structure, and has good stretchability, and still has a capacitance retention rate of more than 95% when the stretching rate is 100%, and is suitable for application in wearable medical monitoring, communication equipment or other small electronic products, and fills the gap of three-dimensional stretchable electrode application;

[0063] (2) The three-dimensional artificial turf fabric formed in one piece compensates for the defect that the three-dimensional electrode fluff prepared by the static flocking technology is not firmly attached, and the fluff formed by free breaking during the weaving process is uniformly distributed, and the preparation operation is simple, and large-scale production is easy to realize;

[0064] (3) The present application can form three-dimensional artificial turf fabric base electrode materials of different specifications by controlling the process parameters of the flat knitting machine without the need for external adhesive materials, and the three-dimensional stretchable electrode can be directly used as a wearable micro-capacitor electrode, and does not need current collector and support material when packaged into a micro-supercapacitor, and does not need adhesive to form an electrode, and can realize a self-supporting structure, and has great industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 The process schematic diagram for preparing a micro-supercapacitor for the embodiment 1 of the present application;

[0066] Figure 2 The photo of the stretchable artificial turf fabric woven by the computer of the flat knitting machine for the embodiment 1 of the present application;

[0067] Figure 3 The SEM diagram of the carbon fiber prepared in step c of the embodiment 1 of the present application;

[0068] Figure 4 The SEM diagram of the artificial turf fabric prepared in step e of the embodiment 1 of the present application;

[0069] Figure 5 The SEM diagram of the stretchable artificial turf fabric electrode prepared in step h of the embodiment 1 of the present application, (a) x 50, (b) x 1.5;

[0070] Figure 6 The constant current charge-discharge curve of the micro-capacitor prepared in the embodiment 1 under different current densities;

[0071] Figure 7 The cyclic voltammetry curve of the micro-supercapacitor prepared in the embodiment 1 under different scanning rates;

[0072] Figure 8Galvanostatic charge-discharge curves of the micro-supercapacitor prepared in Example 1 were performed at a current density of 1 A / g for 5000 times of galvanostatic charge-discharge. DETAILED DESCRIPTION

[0073] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application.

[0074] Example 1

[0075] The present embodiment provides a preparation method of a stretchable turf-like fabric electrode, comprising the following steps:

[0076] Step a, put kapok fibers into 2% sodium hydroxide solution, the ratio of material to liquid is 1g:8mL, immerse at room temperature for 50h, take out and wash to neutral with deionized water, put into a 120℃ oven to dry, get alkali treated kapok fibers;

[0077] Step b, mix the above alkali treated kapok fibers, sodium hypophosphite and water according to the mass ratio of 1:1.5:4, immerse at room temperature for 30min, put into a 100℃ oven to dry, get salt treated kapok fibers;

[0078] Step c, put the above salt treated kapok fibers into a tube furnace, heat to 180℃ at a rate of 3℃ / min, pre-oxidize under air atmosphere for 2h, then pass nitrogen, heat to 650℃ at a rate of 1.5℃ / min, calcine for 1.5h, drop to room temperature, take out, add 1mol / L hydrochloric acid solution, the ratio of material to liquid is 1g:10mL, immerse at room temperature for 1h, wash with deionized water, dry, get carbon fibers;

[0079] Step d, put the above carbon fibers into a solution of polyoxyethylene fatty acid ester with a mass concentration of 15%, the ratio of material to liquid is 1g:10mL, immerse at room temperature for 30min, wash with deionized water, dry, get pretreated carbon fibers;

[0080] Step e, introduce the above pretreated carbon fibers and cotton yarn (95 / 5) into a computerized flat knitting machine, computerized flat knitting machine knitting is performed in the preset conductive area and insulating area, get a turf-like fabric;

[0081] Step f, soak the turf-like fabric into an ethanol aqueous solution with a concentration of 35%, the ratio of material to liquid is 1g:8mL, the soaking time is 30min, wash with water, dry, get a pretreated fabric electrode material;

[0082] Step g, using the pretreated fabric electrode material as the working electrode, a saturated calomel electrode as the reference electrode, a copper electrode as the counter electrode, and a mixed solution of 0.5 mol / L copper sulfate and 0.2 mol / L boric acid as the electrolyte, at 2 mA / cm 2 Conduct constant current deposition for 90 min to obtain electrode precursor material;

[0083] Step h: adding the above electrode precursor material to 20 mL of 0.1 mmol / L thiourea aqueous solution, mixing evenly, hydrothermally reacting at 120° C. for 25 h, washing with water, and drying to obtain a stretchable turf-like fabric electrode.

[0084] The stretchable turf-like fabric electrodes were assembled into micro supercapacitors:

[0085] 4 g of polyvinyl alcohol, 8.5 g of anhydrous lithium chloride and 40 mL of water were added to a 100 mL beaker and stirred rapidly at 85 ° C for 2 h, and then continued to stir and cool to room temperature to obtain a gel electrolyte. 2 ) were immersed in this gel electrolyte for 6 h, and PET film was used as the packaging material for the external packaging of the electrode material.

[0086] The schematic diagram of the process of preparing a micro supercapacitor in this embodiment is as follows Figure 1 As shown, the prepared stretchable turf-like fabric is shown in the photo Figure 2 shown.

[0087] Example 2

[0088] This embodiment provides a method for preparing a stretchable turf-like fabric electrode, comprising the following steps:

[0089] Step a, placing kapok fiber in a 2% sodium hydroxide solution with a solid-liquid ratio of 1 g:10 mL, immersing at room temperature for 40 hours, taking out and washing with deionized water until neutral, and drying in an oven at 120° C. to obtain alkali-treated kapok fiber;

[0090] Step b, mixing the alkali-treated kapok fiber, sodium hypophosphite and water in a mass ratio of 1:2.5:6, soaking at room temperature for 45 minutes, and drying in an oven at 100° C. to obtain salt-treated kapok fiber;

[0091] Step c, placing the salt-treated kapok fiber in a tube furnace, heating it to 200°C at a rate of 5°C / min, pre-oxidizing it in an air atmosphere for 1.5 hours, then introducing nitrogen, heating it to 700°C at a rate of 2°C / min, calcining it for 1 hour, cooling it to room temperature, taking it out, adding it to a 1.5 mol / L hydrochloric acid solution with a material-liquid ratio of 1 g:8 mL, soaking it at room temperature for 1.5 hours, washing it with deionized water, and drying it to obtain carbon fiber;

[0092] Step d, the above-mentioned carbon fiber is added into a fatty acid polyoxyethylene ester solution with a mass concentration of 20%, the material-liquid ratio is 1 g:8 mL, and the pretreated carbon fiber is immersed at room temperature for 45 min, washed with deionized water, and dried;

[0093] Step e, the above-mentioned pretreated carbon fiber and cotton yarn (95 / 5) are introduced into a computerized flat knitting machine, and are knitted by using a single-head single-system knitting system, taking the pretreated carbon fiber as weft and taking the yarn as warp, and the computerized flat knitting machine is knitted in the preset conductive area and insulating area, to obtain a simulated turf fabric;

[0094] Step f, the above-mentioned simulated turf fabric is soaked in an ethanol aqueous solution with a concentration of 25%, the material-liquid ratio is 1 g:10 mL, and the soaking time is 45 min, and then the simulated turf fabric is washed with water and dried, to obtain a pretreated fabric electrode material;

[0095] Step g, the pretreated fabric electrode material is used as a working electrode, a saturated calomel electrode is used as a reference electrode, a copper electrode is used as a counter electrode, and a mixed solution of 1.0 mol / L copper sulfate and 0.3 mol / L boric acid is used as an electrolyte, and a constant current deposition is performed at 5 mA / cm 2 for 70 min, to obtain an electrode precursor material;

[0096] Step h, the above-mentioned electrode precursor material is added into 15 mL of a 0.2 mmol / L thiourea aqueous solution (3 mmol is added into 15 mL of water), and is uniformly mixed, and is hydrothermally reacted at 130℃ for 20 h, and then is washed with water and dried, to obtain a stretchable simulated turf fabric electrode.

[0097] The above-mentioned stretchable simulated turf fabric electrode is assembled into a micro supercapacitor in the same manner as in Example 1.

[0098] Example 3

[0099] The present embodiment provides a preparation method of a stretchable simulated turf fabric electrode, comprising the following steps:

[0100] Step a, kapok fibers are put into a 3% sodium hydroxide solution, the material-liquid ratio is 1 g:9 mL, and the kapok fibers are immersed at room temperature for 48 h, and then are taken out, washed with deionized water until neutral, and dried in a 120℃ oven, to obtain alkali-treated kapok fibers;

[0101] Step b, the above-mentioned alkali-treated kapok fibers, sodium hypophosphite and water are mixed according to a mass ratio of 1:2:5, and are immersed at room temperature for 35 min, and then are dried in a 100℃ oven, to obtain salt-treated kapok fibers;

[0102] Step c, placing the salt-treated kapok fiber in a tube furnace, heating it to 190°C at a rate of 4°C / min, pre-oxidizing it in an air atmosphere for 2 hours, then introducing nitrogen, heating it to 680°C at a rate of 2°C / min, calcining it for 1.5 hours, cooling it to room temperature, taking it out, adding it to a 1 mol / L hydrochloric acid solution with a material-liquid ratio of 1g:9mL, soaking it at room temperature for 1.5 hours, washing it with deionized water, and drying it to obtain carbon fiber;

[0103] Step d, adding the above carbon fiber to a fatty acid polyoxyethylene ester solution with a mass concentration of 18%, with a solid-liquid ratio of 1g:9mL, immersing at room temperature for 40min, washing with deionized water, and drying to pretreat the carbon fiber;

[0104] Step e, introducing the pretreated carbon fiber and cotton nylon (95 / 5) into a computerized flat knitting machine, using a single-head single-system weaving system, using the pretreated carbon fiber as the weft and the yarn as the warp for weaving, and performing computerized flat knitting in the preset conductive area and the insulating area to obtain a turf-like fabric;

[0105] Step f, soaking the imitation turf fabric in a 30% ethanol aqueous solution with a material-liquid ratio of 1 g:9 mL for 35 min, washing with water, and drying to obtain a pretreated fabric electrode material;

[0106] Step g, using the pretreated fabric electrode material as the working electrode, a saturated calomel electrode as the reference electrode, a copper electrode as the counter electrode, and a mixed solution of 0.7 mol / L copper sulfate and 0.2 mol / L boric acid as the electrolyte, at 4 mA / cm 2 Conduct constant current deposition for 80 min to obtain electrode precursor material;

[0107] Step h: adding the above electrode precursor material to 18 mL of 0.15 mmol / L thiourea aqueous solution and mixing evenly, hydrothermally reacting at 125° C. for 24 h, washing with water, and drying to obtain a stretchable turf-like fabric electrode.

[0108] The stretchable turf-like fabric electrodes were assembled into a micro supercapacitor in the same manner as in Example 1.

[0109] The specific steps of computerized flat knitting in the above embodiments 1-3 are as follows:

[0110] S1, according to the design pattern of the knitted fabric, cotton / spandex yarn is knitted in a preset insulation area on the front needle bed of a computerized flat knitting machine by plain stitch to obtain a plain stitch insulation structure;

[0111] S2, at the connection between the cotton / spandex yarn and the pretreated carbon fiber, the cotton / spandex yarn is used to weave a tuck loop at the outermost needle of the carbon fiber weaving area for connection;

[0112] S3, in a preset conductive range, the pretreated carbon fibers are weft flat needle knitted on the front needle bed of the computerized flat knitting machine to obtain a weft flat needle conductive organization;

[0113] S4, S2, S1, S2 are repeated in sequence;

[0114] S5, in a preset conductive range, the front needle bed and the back needle bed are adjusted to be staggered, and the pretreated carbon fibers are tuck knitted on the front and back needle beds to form long loops on the back of the weft flat needle organization;

[0115] S6, S2, S1, S2 are repeated in sequence;

[0116] S7, in a preset conductive range, the pretreated carbon fibers are weft flat needle knitted on the front needle bed again;

[0117] S8, the back needle bed is lowered, and the tuck yarn of the back needle bed in the preset conductive range is pulled off;

[0118] S9, S2, S1 are repeated in sequence;

[0119] S10, S2-S9 are repeated in sequence until the knitting is completed.

[0120] The cotton / spandex yarn adopts 10 pure cotton yarns and 40D spandex covered yarn.

[0121] Comparative Example 1

[0122] The present comparative example provides a preparation method of a stretchable artificial turf fabric electrode, which is completely same as that of Example 1, except that the alkali-treated kapok fibers obtained in step a are directly subjected to the oxidative calcination treatment in step c without the salt treatment process in step b.

[0123] Morphology characterization

[0124] The SEM image of the carbon fibers prepared in step c of Example 1 is shown in Figure 3 The SEM image of the artificial turf fabric prepared in step e is shown in Figure 4 It can be seen from the figure that the surface carbon fibers of the fabric prepared in Example 1 of the present application are free to break to form an artificial fur effect. The SEM image of the stretchable artificial turf fabric electrode prepared in step h is shown in Figure 5 It can be seen from the figure that CuS is uniformly loaded on the surface of the carbon fibers and presents a sheet structure.

[0125] Performance test

[0126] The test assembled capacitor adopts a two-electrode test system, the working electrode is the prepared electrode material, the test electrolyte is a polyvinyl alcohol / lithium chloride gel electrolyte (4 g of polyvinyl alcohol, 8.5 g of anhydrous lithium chloride and 40 mL of water form a gel electrolyte with 100 mL of water), and cyclic voltammetry, constant current charge and discharge and cycle performance tests are carried out thereon.

[0127] (1) Charge and discharge performance test

[0128] The micro-capacitor prepared in Example 1 is subjected to constant current charge and discharge test at different current densities, and the current densities are 1 A / g, 2 A / g, 4 A / g and 8 A / g, respectively, and the results are shown in Figure 6 .

[0129] As can be seen from the figure, it does not show a strict voltage-time linear relationship, and the main reason is the pseudo-capacitance reaction caused by the doping of phosphorus element in the electrode material, and the initial voltage drop of the discharge curve indicates that the electrode material has a certain internal resistance. Even so, when the current density increases from 1 A / g to 8 A / g, it still shows a high coulomb efficiency, which proves that the ion transference rate of the electrode material prepared in the embodiment of the application is high, the transition time is short, and the electrode material has excellent charge and discharge performance.

[0130] (2) Cyclic voltammogram

[0131] The micro-supercapacitor prepared in Example 1 is subjected to cyclic voltammetry test at different scanning rates, and the scanning rates are 5 mV / s, 20 mV / s, 50 mV / s, 100 mV / s and 200 mV / s, respectively, and the results are shown in Figure 7 .

[0132] As can be seen from the figure, it still has a high capacitance of 49.43 F / cm 3 at 20 mV / s, the response current of the micro-capacitor within 0-1.2V increases smoothly with the increase of the scanning rate, and no obvious hydrogen evolution and oxygen absorption reaction occurs. Even at a high scanning rate of 100 mV / s, the micro-supercapacitor can still maintain a similar rectangular symmetry shape, which indicates that the micro-supercapacitor prepared in the embodiment of the application has a high electrolyte ion diffusion and transmission rate.

[0133] (3) Cycle stability test

[0134] The micro-supercapacitor prepared in Example 1 is subjected to constant current charge and discharge for 5000 times at a current density of 1 A / g, and the specific capacitance and energy density of the supercapacitor are calculated according to the constant current charge and discharge curve, and the results are shown in Figure 8 and Tables 1-3, and the calculation formula of the specific capacitance and energy density is as follows:

[0135]

[0136]

[0137] wherein C m is the mass specific capacitance (F / g) of the electrode material, m is the mass of the electrode active material (g), ΔV is the working voltage window (excluding the voltage drop at the initial stage of discharge), Δt is the discharge time (s), I is the applied test current (A), E cell is the energy density (Wh / kg).

[0138] (4) Performance test of symmetric supercapacitor in tensile state

[0139] The capacitance performance of the assembled supercapacitor after stretching by 20% and 50% refers to stretching the assembled micro-supercapacitor to 120% and 150% of the original length, then performing PET film packaging treatment, testing the voltage window, specific capacitance and energy density according to the above method, and the results are shown in Tables 1-3.

[0140] (5) Fastness test

[0141] According to the standard "GB / T21196-2007 Determination of Fabric Abrasion Resistance by the Martindale Method", the abrasion resistance of the front and back surfaces of the artificial turf fabric prepared in step e was tested using a Martindale abrasion tester, and the electrical conductivity and capacitance performance before and after friction were tested. The results are shown in Tables 1-3.

[0142] The washing resistance of the front and back surfaces of the artificial turf fabric prepared in step e was tested according to the standard "GB / T3921-2008 Determination of Fabric Washing Fastness", and the electrical conductivity and capacitance performance before and after washing were tested. The results are shown in Tables 1-3.

[0143] Table 1: Capacitance performance test results of micro-capacitors prepared in Example 1 and Comparative Example 1

[0144]

[0145] Table 2: Capacitance performance test results of micro-capacitors prepared in Example 2

[0146]

[0147]

[0148] Table 3: Capacitance performance test results of micro-capacitors prepared in Example 3

[0149]

[0150] In summary, the three-dimensional stretchable electrode constructed by the application has very good conductivity, stretchability and mechanical properties, which can combine with gel electrolyte to directly form wearable micro-supercapacitor, does not need current collector and support material when packaged into micro-supercapacitor, and does not need adhesive and other plastic electrodes, can realize self-supporting structure, and has simple preparation process, greatly reduces the cost, realizes the large-scale production of high-capacitance electrodes, and has great industrial application value.

[0151] The above merely describes preferred embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement or improvement made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A method for preparing a stretchable turf-like fabric electrode material, characterized in that: The steps include: Step a, soaking kapok fibers in a strong alkaline solution, washing, and drying to obtain alkali-treated kapok fibers; Step b, adding the alkali-treated kapok fiber and sodium hypophosphite into water, immersing, and drying to obtain salt-treated kapok fiber; Step c, subjecting the salt-treated kapok fiber to low-temperature oxidation at 180-200° C. in an air atmosphere, and then subjecting it to high-temperature calcination at 650-700° C. in an inert atmosphere, cooling it, and impregnating it in a strong acid solution to obtain carbon fiber; Step d, adding the carbon fiber to an aqueous solution of a polyoxyethylene ether surfactant, immersing at 90-100° C., washing with water, and drying to obtain pretreated carbon fiber; Step e, knitting the pretreated carbon fiber and cotton / spandex yarn in a predetermined conductive area and insulating area using a computerized flat knitting machine to obtain a stretchable turf-like fabric electrode material; In step e, the specific steps of computer flat knitting are: S1, according to the design pattern of the knitted fabric, cotton / spandex yarn is knitted in a preset insulation area on the front needle bed of a computerized flat knitting machine by plain stitch to obtain a plain stitch insulation structure; S2, at the connection between the cotton / spandex yarn and the pretreated carbon fiber, the cotton / spandex yarn is used to weave a tuck loop at the outermost needle of the carbon fiber weaving area for connection; S3, within a preset conductive range, knitting the pretreated carbon fiber on the front needle bed of a computerized flat knitting machine using a plain weft needle to obtain a plain weft conductive structure; S4, repeat S2, S1, S2 in sequence; S5, within a preset conductive range, adjusting the front needle bed and the rear needle bed to be staggered, and performing tuck weaving on the pretreated carbon fiber on the front and rear needle beds to form a long coil on the back of the weft plain needle insulation structure; S6, repeat S2, S1, S2 in sequence; S7, within a preset conductivity range, the pretreated carbon fiber is again weft-knitted on the front needle bed; S8, lowering the knitting needles of the rear needle bed to break the tuck yarn of the rear needle bed in the preset conductive range; S9, repeat S2 and S1 in sequence; S10, repeat S2-S9 in sequence until the weaving is completed.

2. The method for preparing the stretchable turf-like fabric electrode material according to claim 1, wherein: In step a, the strong alkaline solution is a sodium hydroxide solution with a mass concentration of 2%-3%, and the immersion time is 40-50h; and / or In step a, the ratio of the kapok fiber to the strong alkaline solution is 1 g: 8-10 mL; and / or In step b, the mass ratio of the alkali-treated kapok fiber, sodium hypophosphite and water is 1:1.5-2.5:4-6, and the immersion time is 30-45 minutes.

3. The method for preparing the stretchable turf-like fabric electrode material according to claim 1, wherein: In step c, the low temperature oxidation time is 1.5-2h; and / or In step c, the temperature is raised to 180-200°C by programmed heating at a heating rate of 3-5°C / min; and / or In step c, the temperature is raised to 650-700°C by programmed heating at a heating rate of 1.5-2°C / min; and / or In step c, the high temperature calcination time is 1-1.5h; and / or In step c, the strong acid solution is a 1-1.5 mol / L hydrochloric acid solution, and the immersion time is 1-1.5 h.

4. The method for preparing the stretchable turf-like fabric electrode material according to claim 2, wherein: In step d, the polyoxyethylene ether surfactant is at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyether or ethoxylated fatty acid sorbitan ester; and / or In step d, the concentration of the polyoxyethylene ether surfactant in the aqueous solution is 15wt%-20wt%; and / or In step d, the immersion time is 30-45 minutes.

5. A stretchable turf-like fabric electrode material, characterized in that: The stretchable turf-like fabric electrode material is prepared by the preparation method of any one of claims 1 to 4.

6. Use of the stretchable turf-like fabric electrode material according to claim 5 in a supercapacitor.

7. A supercapacitor electrode, characterized in that: The invention comprises the stretchable turf-like fabric electrode material according to claim 1, and nano-sheet copper sulfide loaded on the surface of the stretchable turf-like fabric electrode material.

8. The method for preparing a supercapacitor electrode according to claim 7, wherein: The steps include: Step S1, soaking the stretchable turf-like fabric electrode material in an ethanol aqueous solution, washing with water, and drying to obtain a pretreated fabric electrode material; Step S2, using the pretreated fabric electrode material as a working electrode, a saturated calomel electrode as a reference electrode, a copper electrode as a counter electrode, and a mixed solution of copper sulfate and boric acid as an electrolyte, performing constant current deposition to obtain an electrode precursor material; Step S3, adding the electrode precursor material and thiourea into water and mixing evenly, hydrothermally reacting at 120-130° C. for 20-25 hours, washing with water, and drying to obtain the supercapacitor electrode.

9. A supercapacitor, characterized in that: The supercapacitor electrode according to claim 7 is included.

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