Sunlight-resistant Colorful Electrochemical Energy Storage Fabric Based on Recycled Cotton Powder and Its Preparation Method

Abstract

The present application provides a sunlight-resistant colored electrochemical energy storage fabric based on recycled cotton powder and a preparation method thereof, belonging to the technical fields of flexible electronic textiles and electrochemical energy storage. The preparation method first deposits a TiO2 film on the recycled cotton powder by ALD technology, and then performs mild hydrothermal synthesis to obtain a TMOs@TiO2@CP composite powder with a three-layer nested structure. Among them, the TiO2 film protects the internal recycled cotton powder from erosion during the hydrothermal reaction and is tightly combined with the TMOs functional layer through Ti-O-TM covalent bonds, improving the structural stability and interfacial bonding force of the composite powder. The present application uses the inherent color characteristics of different transition metal oxides to replace traditional black carbon-based materials, endowing the energy storage fabric with rich color choices and meeting the aesthetic and design requirements of high-end textiles. The process route of the present application avoids the damage to the inherent flexibility and structure of cotton fabrics by drastic means such as high-temperature carbonization.

Description

Technical Field

[0001] This invention relates to the fields of flexible electronic textiles and electrochemical energy storage technology, specifically to a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder and its preparation method. Background Technology

[0002] With the rapid development of wearable electronic devices, the demand for flexible, lightweight, and environmentally adaptable energy storage devices is increasing. Integrating energy storage functionality into everyday textiles is an effective way to achieve this goal. However, existing flexible energy storage fabric electrodes are mostly black, dominated by carbon materials (such as PPy and MXene), resulting in a monotonous appearance that fails to meet the diverse color and personalized design requirements of high-end textiles.

[0003] In terms of manufacturing processes, traditional methods such as high-temperature carbonization or chemical polymerization involve harsh conditions that can easily damage the inherent flexibility, breathability, and mechanical structure of fabrics. Conventional metal oxide growth or direct dyeing methods generally suffer from poor adhesion between active substances and the substrate, insufficient color fastness, and poor antioxidant and sunlight resistance. Furthermore, although transition metal oxides (TMOs) possess a rich array of inherent colors and theoretical capacitance, their poor conductivity, low loading capacity on fabric substrates, and tendency to agglomerate severely limit their performance in practical applications.

[0004] Therefore, developing a flexible energy storage material that can give fabrics a colorful appearance while ensuring excellent electrochemical performance, high stability, and good wearing comfort remains a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder and its preparation method. This fabric uses recycled cotton powder as the core substrate and achieves an effective synergy of color diversity, high electrochemical performance, and excellent environmental stability through a mild process route.

[0006] This application provides a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, comprising the following steps: S1. Preparation of TiO2@CP intermediate: The recycled cotton powder was placed in the atomic layer deposition reaction chamber, and ALD deposition was performed using tetraisopropyl titanate and deionized water as precursors to form a TiO2 film on the surface of the recycled cotton powder, thus obtaining the TiO2@CP intermediate; S2. Preparation of TMOs@TiO2@CP composite powder: The TiO2@CP intermediate obtained in step S1 is dispersed in a reaction solution containing a transition metal oxide precursor. The transition metal oxide functional layer is directionally grown on the surface of TiO2@CP by hydrothermal synthesis to obtain TMOs@TiO2@CP composite powder. S3. Preparation of functionalized color paste: Silver nanowires, TMOs@TiO2@CP composite powder obtained in step S2, distilled water, and sodium carboxymethyl cellulose are mixed and magnetically stirred to form a uniform and viscous fluid; S4. Screen printing: Using screen printing technology, the functionalized color paste obtained in step S3 is printed onto the surface of the cotton fabric to form an electrode layer, thus obtaining a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder.

[0007] Further, in step S2, when the TMOs are Fe2O3, the preparation process is as follows: FeCl3 solution is mixed with NaOH solution, and then TiO2@CP intermediate is added, and the mixture is hydrothermally reacted at 150-170℃ for 1.5-2.5 hours.

[0008] Further, in step S2, when TMOs are MoO3, the preparation process is as follows: ammonium molybdate solution is mixed with concentrated nitric acid, and then TiO2@CP intermediate is added, and hydrothermal reaction is carried out at 150-170℃ for 7-9 hours.

[0009] Further, in step S2, when TMOs are WO3, the preparation process is as follows: the pH of the sodium tungstate solution is adjusted to 1-2 with hydrochloric acid, and then TiO2@CP intermediate is added, and the mixture is hydrothermally reacted at 170-190℃ for 10-14 hours.

[0010] Further, in step S2, when TMOs are MnO2, the preparation process is as follows: potassium permanganate solution is mixed with anhydrous ethanol, TiO2@CP intermediate is added, and hydrothermal reaction is carried out at 140-160℃ for 10-14 hours.

[0011] This application also provides a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, which is prepared by the preparation method described in any of the foregoing technical solutions. The sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder includes a cotton fabric substrate and an electrode layer formed on the cotton fabric. The electrode layer is formed by curing functionalized pigments through a screen printing process. The functionalized pigments include conductive materials, binders, and TMOs@TiO2@CP composite powder. The TMOs@TiO2@CP composite powder has a three-layer core-shell structure, which consists of, from the inside out: recycled cotton powder, a TiO2 film coated on the surface of the recycled cotton powder, and a transition metal oxide functional layer grown on the surface of the TiO2 film.

[0012] Furthermore, the recycled cotton powder consists of micron-sized irregular particles with a particle size range of 500 nm to 200 μm; the TiO2 film is a uniform film with a thickness of 10-12 nm, prepared by atomic layer deposition technology.

[0013] Furthermore, the transition metal oxide functional layer is one of Fe2O3, MoO3, WO3 or MnO2, which respectively makes the fabric appear reddish-brown, light green, light gray or black.

[0014] Furthermore, the conductive material is silver nanowires, which are linear structures with nanometer-scale diameters and micrometer-scale lengths, uniformly dispersed to form a continuous conductive network; the binder is sodium carboxymethyl cellulose.

[0015] Furthermore, the functionalized color paste is composed of: 45-55mg silver nanowires, 18-22mg TMOs@TiO2@CP composite powder, 3.5-4.5ml distilled water, and 0.1-0.3g sodium carboxymethyl cellulose.

[0016] The beneficial effects of this application are as follows: 1. This application proposes a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder. The method first deposits a TiO2 film on the recycled cotton powder using ALD technology, followed by mild hydrothermal synthesis (140-180℃) to obtain a TMOs@TiO2@CP composite powder with a three-layer nested structure. The dense TiO2 film acts as a physical barrier, protecting the internal recycled cotton powder core from erosion during the hydrothermal reaction, and is tightly bonded to the TMOs functional layer through Ti-O-TM covalent bonds, significantly improving the structural stability and interfacial bonding of the composite powder.

[0017] Specifically, this application employs a process route of "low-temperature ALD coating (80℃) + mild hydrothermal synthesis (140-180℃)," avoiding the damage to the inherent flexibility and structure of cotton fabrics caused by harsh methods such as high-temperature carbonization. Simultaneously, the TiO2 film can protect the recycled cotton powder and provide more active sites for the hydrothermal synthesis reaction. Furthermore, this application prepares four transition metal oxides—Fe2O3 (reddish-brown), MoO3 (light green), WO3 (light gray), and MnO2 (black)—on TiO2-coated cotton powder via hydrothermal synthesis. Utilizing the inherent color characteristics of transition metal oxides, these materials replace traditional black carbon-based materials. A conductive network is constructed using transparent silver nanowires, ensuring conductivity without obscuring the natural color, thus providing the energy storage fabric with a rich selection of colors and meeting the aesthetic and design needs of high-end textiles.

[0018] 2. The process conditions of this application are mild, avoiding damage to cotton fabrics and powders caused by high temperatures and violent chemical reactions. Furthermore, compared to conventional oxide growth and direct dyeing, the strong chemical bonding between the TiO2 film grown by ALD and the TMOs functional layer, as well as the dense structure, endow the prepared electrodes with excellent lightfastness (e.g., lightfastness of Fe2O3 and MnO2-based fabrics reaches grade 4-5) and antioxidant capacity. Combined with the high design flexibility of screen printing (customizable patterns and replaceable pigments), this energy storage fabric can meet the stringent requirements of wearable devices for flexibility, durability, environmental adaptability, and personalized appearance, showing broad application prospects in high-end fields such as medical monitoring and smart clothing.

[0019] 3. This application uses micron-sized recycled cotton powder as the core, whose high specific surface area provides ample space for TMOs loading. The TiO2 layer grown by ALD provides abundant nucleation sites, guiding the uniform and orderly growth of TMOs nanostructures (such as nanosheets, nanoribbons, and nanorods), thus solving the problems of uneven dispersion and low loading of active materials. At the same time, the three-dimensional conductive network formed by silver nanowires in the pigment paste effectively compensates for the poor conductivity of TMOs and reduces the internal resistance of the electrode (e.g., the ESR of the Fe2O3-based electrode is as low as 14.8Ω), achieving a balance between high active material loading and high conductivity.

[0020] 4. This application utilizes recycled cotton powder as raw material, achieving high-value utilization of waste resources. The screen printing technology employed is simple, has high deposition efficiency, high material utilization rate, and good repeatability, making it easy to achieve continuous roll-to-roll production, reducing production costs, and facilitating industrial promotion.

[0021] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0023] Figure 1 This is a schematic diagram of the process flow for the TMOs@TiO2@CP composite powder in this application.

[0024] Figure 2Scanning electron microscope images of recovered cotton powder and TiO2@CP; where (a) is the recovered cotton powder and (b) is TiO2@CP.

[0025] Figure 3 This is a schematic diagram of the process of printing functionalized color paste onto the surface of cotton fabric using screen printing technology in this application.

[0026] Figure 4 The images show actual photos of the energy storage fabrics prepared in Examples 1-4.

[0027] Figure 5 The images show scanning electron microscope (SEM) images of the TMOs@TiO2@CP composite powders prepared in Examples 1-4. (a) represents Fe2O3@TiO2@CP, (b) represents MoO3@TiO2@CP, (c) represents WO3@TiO2@CP, and (d) represents MnO2@TiO2@CP.

[0028] Figure 6 The crystal structures of the four oxides obtained in Examples 1-4 are shown.

[0029] Figure 7 The visual color comparison results of different electrode fabrics before and after simulated sun exposure under xenon arc lamp are shown; where (a) is the visual color comparison and (b) is the rating of the blue wool standard sample.

[0030] Figure 8 This is a comparison chart of the K / S values ​​of different electrode fabrics before and after sun exposure in this invention.

[0031] Figure 9 L before and after sun exposure for different electrode fabrics in this invention a b Scatter plot of chromaticity space distribution.

[0032] Figure 10 Cyclic voltammetry (CV) curves of four different powder double-symmetric electrodes at a scan rate of 500 mV / s.

[0033] Figure 11 The Nyquist plots are for four different powder double-symmetric electrodes under the initial conditions.

[0034] Figure 12 Constant current charge-discharge (GCD) curves for four different powder-printed double-symmetric electrodes. Detailed Implementation

[0035] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0037] Please see Figures 1 to 3 As shown in the figure, this application provides a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, including the following steps: S1. Preparation of TiO2@CP intermediate: The recycled cotton powder was placed in the atomic layer deposition reaction chamber, and ALD deposition was performed using tetraisopropyl titanate and deionized water as precursors to form a TiO2 film on the surface of the recycled cotton powder, thus obtaining the TiO2@CP intermediate; S2. Preparation of TMOs@TiO2@CP composite powder: The TiO2@CP intermediate obtained in step S1 is dispersed in a reaction solution containing a transition metal oxide precursor. The transition metal oxide functional layer is directionally grown on the surface of TiO2@CP by hydrothermal synthesis to obtain TMOs@TiO2@CP composite powder. The TMOs@TiO2@CP composite powder has a three-layer core-shell structure, consisting of, from the inside out: recycled cotton powder (CP), a TiO2 film coated on the surface of the recycled cotton powder, and a transition metal oxide functional layer grown on the surface of the TiO2 film.

[0038] Among them, recycled cotton powder (CP) consists of micron-sized irregular particles with a particle size ranging from 500nm to 200um. Compared with yarn and fabric, recycled cotton powder has a larger specific surface area and is rich in hydroxyl groups on its surface. As a carrier, it provides stable support for subsequent functional layers while retaining the inherent lightweight and flexible properties of cotton materials.

[0039] TiO2 thin films are uniform films with a thickness of 10-12 nm, prepared by atomic layer deposition technology.

[0040] Specifically, using tetraisopropyl titanate (TIP) and deionized water as precursors, a uniform thin film with a thickness of approximately 11.5 nm was formed after 150 pulse cycles at 80°C. Figure 1 As shown, the TiO2 film tightly coats the surface of the recycled cotton powder.

[0041] Figure 2 Image (a) in the image is a scanning electron microscope image of the recovered cotton powder (CP). Figure 2Image (b) is a scanning electron microscope image of the TiO2@CP intermediate, with the corresponding powder image in the lower left corner. The comparison shows that the surface morphology of the recycled cotton powder did not change significantly after being coated with the TiO2 film.

[0042] In this application, the outermost transition metal oxide functional layer is directionally grown on TiO2@CP powder by hydrothermal synthesis. The layers are arranged in a uniform and orderly manner in a strip shape along the longitudinal direction, and each has a unique microstructure.

[0043] S3. Preparation of functionalized color paste: Mix 45-55mg of silver nanowires, 18-22mg of TMOs@TiO2@CP composite powder obtained in step S2, 3.5-4.5mL of distilled water, and 0.1-0.3g of sodium carboxymethyl cellulose (CMC), and stir magnetically to form a uniform and viscous fluid.

[0044] CMC acts as both a binder and a thickener, enabling the silver nanowires to bond firmly with the TMOs@TiO2@CP composite powder and adhere stably to the cotton fabric substrate, ensuring that the electrode layer dries and forms without cracking or peeling after printing.

[0045] In this application, transparent silver nanowires are added to the color paste, which not only compensates for the conductivity defects of TMOs but also does not obscure their inherent color. The CMC binder ensures a strong bond between the composite powder and the cotton fabric substrate, taking into account electrochemical performance, color stability, and textile properties.

[0046] S4. Screen Printing: Using screen printing technology, the functionalized pigment obtained in step S3 is printed onto the surface of the cotton fabric to form an electrode layer. The printed pattern can be customized, and the functionalized pigment has a high deposition rate and uniform thickness with no obvious edge spillage.

[0047] Then, the electrode layer is assembled with LiCl / PVA solid electrolyte, copper foil, etc., to form a complete energy storage fabric structure. In this application, the solid electrolyte is prepared by mixing 8.5 g LiCl, 4 g PVA and 40 mL distilled water and heating to 95°C, which has good ion conductivity and compatibility and does not affect the overall flexibility of the fabric.

[0048] After drying and curing, a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder is obtained.

[0049] This application achieves substrate protection and directional growth of active materials through ALD treatment, achieves both conductivity and color diversity through the synergy of silver nanowires and TMOs, and achieves large-scale and customized production through screen printing, thus producing printed energy storage fabrics with multiple colors, high color fastness, sun protection and electrochemical energy storage performance.

[0050] This fabric can be used in high-end textiles, wearable electronic devices, and other applications.

[0051] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0052] Example 1 This embodiment provides a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, including the following steps: S1. Preparation of TiO2@CP intermediate: 1g of recycled cotton powder (CP) was placed in an atomic layer deposition (ALD) reaction chamber. The first precursor, tetraisopropyl titanate (TIP, stored at room temperature), was pulsed into the reaction chamber for 0.2 seconds, followed by the second precursor, deionized water, pulsed into the chamber for 0.05 seconds. Note that after each precursor pulse, high-purity nitrogen was used as both carrier and purge gas for 30 seconds to remove residual substances. Throughout the process, TiO2 was deposited via a pulsed reaction with a pulse sequence of 0.2 / 8 / 30 / 0.05 / 8 / 30 seconds, corresponding to TIP / exposure / purge / deionized water (H2O) / exposure / purge, respectively. Repeating this process allowed the TIP to react with the deionized water, forming a TiO2 layer on the substrate (recycled cotton powder). The number of ALD cycles for TiO2 was set to 150, and a TiO2@CP intermediate with a thickness of about 11.5 nm was finally obtained. The product was taken out and dried in a vacuum drying oven at 60℃ for later use. S2. Preparation of TMOs@TiO2@CP composite powder: Measure 25 ml of distilled water, dissolve 1 mol / L FeCl3 in it, mix thoroughly and well, and label it as solution A; Measure 25 ml of distilled water, dissolve 4 mol / L NaOH in it, mix thoroughly and label it as solution B; Slowly add solution A to solution B and stir continuously for 15 minutes to obtain a mixed solution; Add about 0.3 g of TiO2-coated recycled cotton powder (TiO2@CP intermediate) to the above mixed solution, mix well, and then transfer to a 100 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene (Teflon); Seal the high-pressure reactor and place it at 160℃ for 2 hours to maintain the temperature. After the reaction is complete, allow the reaction vessel to cool naturally to room temperature, remove the powder from the vessel, and wash it repeatedly with deionized water 5 times. The washed powder was placed at 60℃ to complete the drying process, resulting in Fe2O3@TiO2@CP composite powder.

[0053] S3. Preparation of functionalized color paste: Add 50 mg of silver nanowires, 20 mg of Fe2O3@TiO2@CP composite powder, 4 mL of distilled water and 0.1 g of sodium carboxymethyl cellulose (CMC) to a beaker in sequence and mix. Stir magnetically for 20 minutes until the system forms a uniform and viscous flow state. It should be noted that when conducting subsequent tests on the sunlight resistance of TMOs@TiO2@CP printed functional cotton fabrics, silver nanowires are not added to the functionalized color paste. This is because silver nanowires are prone to photo-oxidation under xenon arc lamp sunlight exposure, which leads to a decrease in their conductivity and may affect the color stability of TMOs@TiO2@CP, interfering with the sunlight resistance test results. At the same time, 30mg of waterborne polyurethane resin (PU) is added to the functionalized color paste. PU acts as a binder, which can ensure stable adhesion between TMOs@TiO2@CP and the cotton fabric substrate.

[0054] S4. Cut a 5cm × 3cm sample from pure white cotton fabric and fix it together with a 200-mesh screen onto the screen printing frame; Pour the prepared functional color paste onto one end of the screen template, and use a scraper to spread the color paste across the screen at a uniform speed, ensuring that the color paste fully fills the mesh and is transferred to the fabric surface; repeat the scraping twice to ensure that the coating on the fabric surface is uniform. After printing, the fabric is immediately transferred to a vacuum drying oven and dried at 60°C and a vacuum of -0.08 MPa for 2 hours to completely remove moisture and fully cure the adhesive, finally obtaining Fe2O3@TiO2@CP printed functional cotton fabric (electrode layer).

[0055] Then, using Fe2O3@TiO2@CP printed functional cotton fabric as the electrode layer, the electrode layer is assembled with LiCl / PVA solid electrolyte, copper foil, etc., to form a complete energy storage fabric structure, as shown in the figure below. Figure 4 As shown. In this embodiment, the solid electrolyte is prepared by mixing 8.5 g LiCl, 4 g PVA and 40 mL distilled water and heating to 95°C. It has good ion conductivity and compatibility and does not affect the overall flexibility of the fabric.

[0056] Example 2 This embodiment provides a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, including the following steps: S1. Repeat step S1 of Example 1; S2. Preparation of TMOs@TiO2@CP composite powder: Weigh 1.11 g of ammonium molybdate ((NH4)2MoO4), dissolve it in 50 mL of deionized water, and stir until completely dissolved; Slowly add 6 ml of concentrated nitric acid to the above ammonium molybdate solution and stir continuously for 30 minutes to obtain a homogeneous mixed solution; then, add about 0.3 g of TiO2-coated recycled cotton powder to the mixed solution, mix evenly, and transfer to a 100 ml stainless steel high-pressure reactor lined with polytetrafluoroethylene, and seal the reactor. The sealed high-pressure reactor was placed at 160℃ and kept at that temperature for 8 hours. After the reaction is complete, allow the reaction vessel to cool naturally to room temperature, remove the powder from the vessel, and wash it three times alternately with distilled water and ethanol to remove residual impurities; The washed powder was placed in a vacuum drying oven at 60℃ and dried for 12 hours to obtain MoO3@TiO2@CP composite powder.

[0057] The difference between steps S3 and S4 and Example 1 is that the TMOs@TiO2@CP composite powder is replaced with MoO3@TiO2@CP composite powder, ultimately obtaining MoO3@TiO2@CP printed functional cotton fabric. Other steps are largely the same as in Example 1 and will not be repeated here.

[0058] Example 3 This embodiment provides a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, including the following steps: S1. Repeat step S1 of Example 1; S2. Preparation of TMOs@TiO2@CP composite powder: Weigh 1.65g of sodium tungstate (Na2WO4·2H2O), dissolve it in 50 mL of deionized water, and stir magnetically until completely dissolved; Slowly add 6 mol / L hydrochloric acid to the above solution to adjust the pH to 1-2, and stir continuously for 30 minutes to form a uniform light green tungstate sol; then add about 0.3 g of TiO2 to coat the recovered cotton powder. Seal the reactor and place it in a forced-air drying oven, and keep it at 180℃ for 12 hours. After the reaction was complete, the reaction vessel was allowed to cool naturally to room temperature. The product was then removed and washed three times alternately with distilled water and ethanol to remove residual Na. + Cl - Impurities; The washed powder was placed in a vacuum drying oven at 60℃ and dried for 12 hours to obtain WO3@TiO2@CP composite powder.

[0059] The difference between steps S3 and S4 and Example 1 is that the TMOs@TiO2@CP composite powder is replaced with WO3@TiO2@CP composite powder, ultimately obtaining WO3@TiO2@CP printed functional cotton fabric. Other steps are largely the same as in Example 1 and will not be repeated here.

[0060] Example 4 This embodiment provides a method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, including the following steps: S1. Repeat step S1 of Example 1; S2. Preparation of TMOs@TiO2@CP composite powder: Weigh 0.79 g of potassium permanganate (KMnO4), dissolve it in 50 mL of deionized water, and stir magnetically until completely dissolved; 5 mL of anhydrous ethanol was slowly added to the above solution as a reducing agent and stirred continuously for 20 min to form a uniform brown-black suspension. Then, 0.3 g of TiO2 was added to coat the recovered cotton powder, and the mixture was ultrasonically dispersed for 5 min. The suspension was then transferred to a 100 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene. After the reaction was complete, the reaction vessel was allowed to cool naturally to room temperature. The product was then removed and washed three times alternately with distilled water and ethanol to remove residual potassium. + Impurities; The washed powder was placed in a vacuum drying oven at 60℃ and dried for 12 h to obtain MnO2@TiO2@CP composite powder.

[0061] The difference between steps S3 and S4 and Example 1 is that the TMOs@TiO2@CP composite powder is replaced with MnO2@TiO2@CP composite powder, ultimately obtaining MnO2@TiO2@CP printed functional cotton fabric. Other steps are largely the same as in Example 1 and will not be repeated here.

[0062] Figure 5 The images show scanning electron microscope (SEM) images of the TMOs@TiO2@CP composite powders prepared in Examples 1-4. (a) represents Fe2O3@TiO2@CP, (b) represents MoO3@TiO2@CP, (c) represents WO3@TiO2@CP, and (d) represents MnO2@TiO2@CP; the lower left corner of the images shows the actual powder.

[0063] As can be seen, Fe2O3@TiO2@CP, MoO3@TiO2@CP, WO3@TiO2@CP, and MnO2@TiO2@CP exhibit reddish-brown, light green, light gray, and black, respectively.

[0064] As can be seen from the SEM images, the four transition metal oxides are all arranged in a uniform and orderly band along the longitudinal direction, each with a unique microstructure: Fe2O3 is a nanosheet aggregate structure, MoO3 is a layered nanoribbon, WO3 is a nanorod, and MnO2 is a nanosheet stacked structure.

[0065] In addition, such as Figure 6 As shown, the four oxides each have a specific crystal structure, of which α-Fe2O3 has a rhombohedral structure, α-MoO3 has an orthorhombic phase structure, h-WO3 has a hexagonal phase structure, and β-MnO2 has a tetragonal phase structure.

[0066] The performance of the four colored fabrics prepared in Examples 1-4 was tested.

[0067] The method for testing lightfastness is as follows: The fabric is tested for colorfastness according to GB / T 8427-2019 "Textiles - Tests for Colorfastness to Artificial Light: Xenon Arc Lamp". The test results are as follows: Figure 7 As shown.

[0068] 100% pure white cotton fabric (WCF), colored cotton fabric (DCF), PU-coated colored cotton fabric (PU@DCF), and PU-coated pure white cotton fabric (PU@WCF) were used as controls.

[0069] Colored cotton fabric refers to dyed fabric based on 100% pure white cotton.

[0070] PU-coated colored cotton fabric refers to pure white cotton fabric with a layer of PU coated on top of its dyed base.

[0071] PU-coated pure white cotton fabric refers to 100% pure white cotton fabric coated with a layer of PU.

[0072] As can be seen, after sun exposure, the cotton fabrics prepared in Examples 1 and 4 showed no obvious color difference between the exposed and unexposed areas, indicating good stability against sunlight. According to the blue wool standard lining fabric rating, the light fastness of the samples reached level four to five.

[0073] The cotton fabrics prepared in Examples 2 and 3 did not show ordinary fading after sun exposure, but instead underwent significant color change, indicating that both exhibit photochromic properties.

[0074] PU@DCF (PU-coated colored cotton fabric) faded after exposure to sunlight, while PU@WCF (PU-coated pure white cotton fabric) did not show significant color change. This indicates that the fading was mainly due to the pigment in the colored fabric itself, rather than the effect of PU. The fact that WCF (pure white cotton fabric) did not show significant color change after sun exposure further proves that the base material does not interfere with the assessment of the sunlight resistance of metal oxides.

[0075] Figure 8 , Figure 9These are graphs showing the color characteristics of different electrode fabrics before and after sun exposure (K / S value comparison), L a b Scatter plot of chromaticity space distribution.

[0076] As can be seen, the K / S values ​​of the exposed and unexposed areas of the cotton fabrics prepared in Examples 1 and 4 are very similar, proving that they have high color stability and excellent sun resistance after sun exposure; while the K / S values ​​of the exposed areas of the cotton fabrics prepared in Examples 2 and 3 change significantly compared to the unexposed areas, which is due to the color change leading to an increase in color depth and thus an increase in K / S values.

[0077] The K / S values ​​of WCF (pure white cotton) and PU@WCF remained almost unchanged before and after sun exposure, indicating that the base material and PU itself do not affect the color depth test results. The K / S value of PU@DCF decreased after sun exposure, corresponding to its visual fading performance, confirming the rule that pigment loss will cause a decrease in color depth.

[0078] This result is consistent with the Lab test results. Figure 9 Further visual evidence shows that the spatial distance between the sun-exposed and unexposed points of Fe2O3 and MnO2 is extremely close, while the point distribution of WO3@TiO2@CP, MoO3@TiO2@CP and the control group shows significant differences. These two findings corroborate each other, indicating that Fe2O3 and MnO2 have excellent resistance to sunlight, while WO3 and MoO3 will undergo color changes when exposed to light, and the fading of colored cotton fabrics is mainly caused by pigment loss.

[0079] Figure 4 The images show actual photos of the energy storage fabrics prepared in Examples 1-4.

[0080] The electrochemical performance of the TMOs@TiO2@CP-based printed electrodes prepared in Examples 1-4 was tested.

[0081] Figure 10 The cyclic voltammetry (CV) curves of four different powder double-symmetric electrodes are shown at a scan rate of 500 mV / s.

[0082] As can be seen, the scan rate is 0.5 V·s -1 At that time, the specific capacitances of the printed electrodes based on Fe2O3@TiO2@CP, MoO3@TiO2@CP, WO3@TiO2@CP and MnO2@TiO2@CP were 5.1, 4.9, 5.0 and 3.4 mF·g, respectively. -1 .

[0083] Among them, Fe2O3@TiO2@CP and WO3@TiO2@CP exhibited higher specific capacitance. All four electrode materials maintained good capacitance performance. This performance difference may be related to the purity of the valence state of the transition metal elements during synthesis, reflecting that the content of effective active material varies in the same mass of active material.

[0084] Figure 11 The Nyquist plots are for four different powder double-symmetric electrodes under the initial conditions.

[0085] The equivalent series resistance (ESR) includes the resistance of the electrolyte and the resistance of the textile electrode. The curves of the four samples are similar in shape, but there are slight differences in the high-frequency region (100 kHz); no obvious semicircle was observed in the high-frequency region, indicating good contact between the active material and the current collector.

[0086] As can be seen, the equivalent series resistances (ESRs) of the symmetrical supercapacitors based on Fe2O3@TiO2@CP, MoO3@TiO2@CP, WO3@TiO2@CP and MnO2@TiO2@CP electrodes are 14.8 Ω, 58.7 Ω, 20.6 Ω and 26.7 Ω, respectively.

[0087] Figure 12 Constant current charge-discharge (GCD) curves for four different powder-printed double-symmetric electrodes.

[0088] As can be seen, the current density is 0.5 mA·g -1 The constant current charge-discharge (GCD) curve at that time is triangular in shape.

[0089] Among them, Fe2O3@TiO2@CP and MoO3@TiO2@CP have longer charging times than discharging times, exhibiting a wider voltage window characteristic; while WO3@TiO2@CP and MnO2@TiO2@CP have better matching of charging and discharging times. Although the discharging time is only a few seconds, it conforms to the linear relationship between the discharge current and the scanning rate in an ideal supercapacitor, showing superior coulombic efficiency.

[0090] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, characterized in that, Includes the following steps: S1. Preparation of TiO2@CP intermediate: The recycled cotton powder was placed in the atomic layer deposition reaction chamber, and ALD deposition was performed using tetraisopropyl titanate and deionized water as precursors to form a TiO2 film on the surface of the recycled cotton powder, thus obtaining the TiO2@CP intermediate; S2. Preparation of TMOs@TiO2@CP composite powder: The TiO2@CP intermediate obtained in step S1 is dispersed in a reaction solution containing a transition metal oxide precursor. The transition metal oxide functional layer is directionally grown on the surface of TiO2@CP by hydrothermal synthesis to obtain TMOs@TiO2@CP composite powder. S3. Preparation of functionalized color paste: Silver nanowires, TMOs@TiO2@CP composite powder obtained in step S2, distilled water, and sodium carboxymethyl cellulose are mixed and magnetically stirred to form a uniform and viscous fluid; S4. Screen printing: Using screen printing technology, the functionalized color paste obtained in step S3 is printed onto the surface of the cotton fabric to form an electrode layer, thus obtaining a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder.

2. The method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, In step S2, when the TMOs are Fe2O3, the preparation process is as follows: FeCl3 solution is mixed with NaOH solution, and then TiO2@CP intermediate is added. The mixture is then subjected to hydrothermal reaction at 150-170℃ for 1.5-2.5 hours.

3. The method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, In step S2, when TMOs are MoO3, the preparation process is as follows: ammonium molybdate solution is mixed with concentrated nitric acid, and then TiO2@CP intermediate is added. The mixture is then subjected to hydrothermal reaction at 150-170℃ for 7-9 hours.

4. The method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, In step S2, when TMOs are WO3, the preparation process is as follows: adjust the pH of the sodium tungstate solution to 1-2 with hydrochloric acid, then add TiO2@CP intermediate, and perform a hydrothermal reaction at 170-190℃ for 10-14 hours.

5. The method for preparing a sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, In step S2, when TMOs are MnO2, the preparation process is as follows: potassium permanganate solution is mixed with anhydrous ethanol, TiO2@CP intermediate is added, and hydrothermal reaction is carried out at 140-160℃ for 10-14 hours.

6. A sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder, characterized in that, The fabric, prepared by the method described in any one of claims 1-5, comprises a cotton fabric substrate and an electrode layer formed on the cotton fabric. The electrode layer is formed by curing functionalized color paste through a screen printing process. The functionalized color paste comprises conductive material, binder, and TMOs@TiO2@CP composite powder. The TMOs@TiO2@CP composite powder has a three-layer core-shell structure, consisting of, from the inside out: recycled cotton powder, a TiO2 film coated on the surface of the recycled cotton powder, and a transition metal oxide functional layer grown on the surface of the TiO2 film.

7. The sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, The recycled cotton powder consists of micron-sized irregular particles with a particle size range of 500 nm to 200 μm; the TiO2 film is a uniform film with a thickness of 10-12 nm, prepared by atomic layer deposition technology.

8. The sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, The transition metal oxide functional layer is one of Fe2O3, MoO3, WO3 or MnO2, which respectively makes the fabric appear reddish-brown, light green, light gray or black.

9. The sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, The conductive material is silver nanowires, which are linear structures with nanometer-scale diameters and micrometer-scale lengths, uniformly dispersed to form a continuous conductive network; the binder is sodium carboxymethyl cellulose.

10. The sun-resistant colored electrochemical energy storage fabric based on recycled cotton powder according to claim 1, characterized in that, The functionalized color paste is composed of: 45-55mg silver nanowires, 18-22mg TMOs@TiO2@CP composite powder, 3.5-4.5ml distilled water and 0.1-0.3g sodium carboxymethyl cellulose.

Images