Inorganic doped electrochromic fabric and method of making the same

Abstract

The application provides an inorganic doped electrochromic fabric and a preparation method thereof. The flexible conductive fabric is first treated with an ammonium sulfate solution for hydrophilic treatment to obtain a pretreated fabric; then a tungsten chloride anhydrous ethanol solution is prepared, and molybdenum pentachloride powder is added to prepare a precursor solution; finally, the pretreated fabric is placed in the precursor solution for high-temperature reaction, and the inorganic doped electrochromic fabric is obtained after the reaction is completed. The flexible conductive fabric is treated with the ammonium sulfate solution, functional treatment is realized, and the surface activity is improved, so that the chemical bonding between the fabric and the electrochromic film is promoted; the molybdenum pentachloride is selected as the precursor, which provides a site for the nucleation and growth of WO3 on the surface of the fabric, so that a stable WO3 and MoO3 composite film is formed, the film serves as an electrochromic layer, the fabric has excellent electrical, optical and mechanical properties, has a fast optical response time and a high coloring efficiency, and can be applied to the fields of smart clothes and implantable display.

Description

Technical Field

[0001] This invention relates to the field of electrochromic fabric technology, and in particular to an inorganic doped electrochromic fabric and its preparation method. Background Technology

[0002] With the development of science and technology and the progress of society, smart color-changing textiles have attracted widespread attention because their color changes can be directly observed by human vision. The ability of textiles to change color, as an important visual signal, has aroused great interest from researchers and consumers. The material that imparts electrochromic properties to fabrics is a key component in determining their color change. Tungsten trioxide (WO3), due to its tunable microstructure and electrical properties, is widely used in various microelectronic devices such as LEDs, DSSCs, and PN junction diodes. Furthermore, WO3, as an inorganic electrochromic material, has also become a research hotspot in recent years.

[0003] An invention patent (application number CN 202010467384.3) discloses a method for preparing a multidimensional WO3 composite electrochromic film. The method involves preparing a mixed solution using potassium oxalate and sodium tungstate, adding dilute hydrochloric acid to adjust the pH value, and preparing a one-dimensional WO3 nanorod precursor reaction solution. Subsequently, a one-dimensional WO3 nanorod film is prepared on the surface of FTO conductive glass using hydrothermal reaction and heat treatment. Then, a two-dimensional WO3 nanosheet precursor reaction solution is prepared using sodium tungstate, dilute hydrochloric acid, and ammonium oxalate. This solution is then used again to prepare two-dimensional WO3 nanosheets on the FTO conductive glass surface loaded with one-dimensional WO3 nanorods, resulting in a multidimensional WO3 composite electrochromic film. However, this preparation method is complex and uses FTO glass as the substrate for film preparation. The glass substrate is then separated from the film material. Since fabrics have a completely different structure from glass, this method is difficult to apply to the preparation of electrochromic fabrics.

[0004] An invention patent (application number CN 202310563551.8) discloses an electrochromic fabric and its preparation method. The method involves mixing oxalic acid and sodium tungstate to adjust the pH and increase the activity of functional groups on the fabric surface, resulting in tungsten trioxide with a special structure that interweaves with the fabric fibers. Simultaneously, n-butanol is added to ensure the stable formation of tungsten trioxide, resulting in a fabric with significant color change and good cycle stability. However, this method uses oxalic acid to adjust the pH and employs n-butanol and hydrochloric acid in combination to promote the bonding of tungsten oxide with the fabric. The chemical reagents are complex, and strict process parameters are required to avoid damaging the fabric structure, leading to low applicability of the method. Furthermore, this method generates chemical waste, putting pressure on environmental protection.

[0005] In view of this, it is necessary to design an improved inorganic doped electrochromic fabric and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an inorganic doped electrochromic fabric and its preparation method. By defining the process and parameters, a composite film of tungsten trioxide and molybdenum trioxide is grown on the surface of a flexible conductive fabric as an electrochromic layer. The electrochromic layer is chemically bonded to the fabric, giving the fabric electrochromic properties and resulting in a high-performance electrochromic fabric for application in fields such as smart clothing and implantable displays.

[0007] To achieve the above-mentioned objective, this invention provides a method for preparing inorganic doped electrochromic fabrics, comprising the following steps:

[0008] S1. The flexible conductive fabric is cleaned and treated with ammonium sulfate solution to obtain a pretreated fabric.

[0009] S2. Prepare an anhydrous ethanol solution of tungsten chloride, add molybdenum pentachloride powder, and stir until homogeneous to obtain a precursor solution; in the precursor solution, the molar ratio of tungsten chloride to molybdenum pentachloride is 10:(1-5).

[0010] S3. Place the pretreated fabric from step S1 into the precursor solution obtained in step S2 and carry out a high-temperature reaction. After the reaction is completed, take out the fabric, wash it several times and dry it to obtain an inorganic doped electrochromic fabric.

[0011] As a further improvement of the present invention, in step S1, the hydrophilic treatment method is to use the cleaned flexible conductive fabric as the positive electrode, the platinum electrode as the negative electrode, the ammonium sulfate solution as the electrolyte, and the constant potential treatment to obtain the pretreated fabric.

[0012] As a further improvement of the present invention, the method for preparing the anhydrous ethanol solution of tungsten chloride is to place 0.005 to 0.010 mol of tungsten chloride in 50 to 100 mL of anhydrous ethanol solvent and stir for 3 to 5 min.

[0013] As a further improvement of the present invention, the concentration of the ammonium sulfate solution is 1-2 mol / L to improve the surface activity of the flexible conductive fabric.

[0014] As a further improvement of the present invention, the constant potential treatment is performed by applying a constant voltage of +5V for 5 to 10 minutes.

[0015] As a further improvement of the present invention, in step S3, the high-temperature reaction process is as follows: the reaction temperature is 100-200°C and the reaction time is 20-24 hours.

[0016] As a further improvement of the present invention, in step S1, the flexible conductive fabric includes one of carbon cloth, conductive cloth, and silver-plated nylon cloth, and the flexible conductive fabric is preferably carbon cloth.

[0017] As a further improvement of the present invention, in steps S1 and S3, the cleaning process involves alternating ultrasonic treatment of the fabric with deionization and ethanol for 20 to 30 minutes, and then drying it in a drying oven at 50 to 70°C for 4 to 12 hours.

[0018] The present invention also provides an inorganic doped electrochromic fabric prepared by any one of the above-mentioned preparation methods, wherein the inorganic doped electrochromic fabric comprises a flexible conductive substrate and a WO3-MoO3 inorganic doped electrochromic layer loaded on the surface of the flexible conductive substrate, and the flexible conductive substrate and the WO3-MoO3 inorganic doped electrochromic layer are chemically bonded together.

[0019] As a further improvement of the present invention, the maximum current value of the inorganic doped electrochromic fabric is not less than 5.5mA, the coloring time is 3 to 6.5s, and the bleaching time is 4 to 8s.

[0020] The beneficial effects of this invention are:

[0021] 1. The method for preparing the inorganic-doped electrochromic fabric of the present invention involves first treating a flexible conductive fabric with ammonium sulfate solution to enhance its hydrophilicity, then placing the pretreated fabric in an anhydrous tungsten chloride ethanol solution containing molybdenum pentachloride powder for a high-temperature reaction. After the reaction is complete, the fabric is removed, washed multiple times, and dried to obtain the inorganic-doped electrochromic fabric. This method, through defined processes and parameters, grows a composite film of tungsten trioxide and molybdenum trioxide on the surface of the flexible conductive fabric as an electrochromic layer. The electrochromic layer is chemically bonded to the fabric, giving it electrochromic properties and resulting in a high-performance electrochromic fabric suitable for applications in smart clothing and implantable displays.

[0022] 2. This invention uses ammonium sulfate solution to perform constant potential treatment on the fabric, which can promote carbon stripping in carbon cloth or cause electron transfer and ion exchange in the metal layer on the surface of other conductive fabrics. It introduces appropriate oxygen-containing functional groups to achieve functionalization, and the treated fabric surface contains a large number of oxygen-containing functional groups such as hydroxyl and carboxyl groups, improving the fabric surface activity, increasing the number of active sites, and significantly enhancing the fabric's wettability, which is beneficial for the chemical bonding between the fabric and the electrochromic film. This invention uses tungsten chloride as the tungsten source, eliminating the need for acid adjustment and avoiding damage to the fabric structure from acid solutions. The synthesized tungsten trioxide is a uniform small-sized nanosphere, eliminating the need for morphology control and reducing the use of chemical reagents. Molybdenum pentachloride is used as a precursor for high-temperature reaction with tungsten chloride. Because molybdenum oxide is more reactive than tungsten oxide, and molybdenum oxide has a better binding force with the fabric, the molybdenum oxide first nucleates on the fabric surface, forming a MoO3 layer, providing sites for the nucleation and growth of WO3. This allows WO3 to gradually grow and adhere, thereby forming a stable composite electrochromic film layer, giving the fabric excellent electrochromic properties.

[0023] 3. This invention uses an anhydrous tungsten chloride ethanol solution containing molybdenum pentachloride powder as a precursor solution to form a composite film of tungsten trioxide and molybdenum trioxide on the fabric surface. Compared with a single WO3 film, MoO3 exhibits stronger and more uniform light absorption in its electrochromic response in the colored state, and also has a better open-circuit memory effect. Therefore, by doping with MoO3, the optimized composite film of WO3 and MoO3 has excellent electrical, optical and mechanical properties, as well as fast optical response time and high coloring efficiency. Attached Figure Description

[0024] Figure 1 This is a SEM image of the inorganic doped electrochromic fabric prepared in Example 1 of the present invention.

[0025] Figure 2 The figure shows the cyclic voltammetric performance test results of the inorganic doped electrochromic fabric prepared in Example 1 of this invention.

[0026] Figure 3 The time-current curve is shown for the inorganic doped electrochromic fabric prepared in Example 1 of this invention.

[0027] Figure 4 This is a SEM image of the inorganic doped electrochromic fabric prepared in Example 2 of the present invention.

[0028] Figure 5 This is a SEM image of the inorganic doped electrochromic fabric prepared in Example 3 of the present invention.

[0029] Figure 6 This is a SEM image of the inorganic doped electrochromic fabric prepared in Example 5 of the present invention.

[0030] Figure 7 SEM image of the electrochromic fabric prepared for Comparative Example 1. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0033] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] A method for preparing an inorganic doped electrochromic fabric includes the following steps:

[0035] S1. The flexible conductive fabric is cleaned and treated with ammonium sulfate solution to obtain a pretreated fabric.

[0036] S2. Prepare an anhydrous ethanol solution of tungsten chloride and add molybdenum pentachloride powder. Stir until homogeneous to obtain a precursor solution. In the precursor solution, the molar ratio of tungsten chloride to molybdenum pentachloride is 10:(1-5). The anhydrous ethanol solution of tungsten chloride is prepared by placing 0.005-0.010 mol of tungsten chloride in 50-100 mL of anhydrous ethanol solvent and stirring for 3-5 min.

[0037] The reason for choosing anhydrous ethanol as the solvent is that tungsten chloride is reactive and will decompose with water to produce chlorine gas. Molybdenum pentachloride powder is even more reactive and easily reacts with water in the air to decompose. Therefore, an anhydrous environment is required. Using anhydrous ethanol as the solvent ensures the reaction stability of the system.

[0038] S3. Place the pretreated fabric from step S1 into the precursor solution obtained in step S2 and carry out a high-temperature reaction at a temperature of 100-200°C for 20-24 hours. After the reaction is completed, take out the fabric, wash it several times, and dry it to obtain the inorganic doped electrochromic fabric.

[0039] Specifically, this invention uses tungsten chloride as the tungsten source, eliminating the need for acid solution adjustment and avoiding damage to the fabric structure caused by acid solutions. Furthermore, the synthesized tungsten trioxide consists of uniform small-sized nanospheres, eliminating the need for morphology control and reducing the use of chemical reagents. Molybdenum pentachloride is selected as the precursor for high-temperature reaction with tungsten chloride because molybdenum oxide is more reactive than tungsten oxide, and molybdenum oxide has a better affinity for the fabric. Therefore, molybdenum oxide first nucleates on the fabric surface, forming a MoO3 layer, which provides sites for the nucleation and growth of WO3. This allows WO3 to gradually grow and adhere, thereby forming a stable composite electrochromic layer, giving the fabric excellent electrochromic properties.

[0040] Specifically, in step S1, the hydrophilic treatment method involves using the cleaned flexible conductive fabric as the positive electrode, a platinum electrode as the negative electrode, and ammonium sulfate solution as the electrolyte, followed by constant potential treatment to obtain the pretreated fabric. The concentration of the ammonium sulfate solution is 1–2 mol / L, and the constant potential treatment is performed using a constant voltage of +5V for 5–10 minutes. Using ammonium sulfate solution for constant potential treatment of the fabric can promote carbon stripping from the carbon cloth or induce electron transfer and ion exchange in the metal layers on the surface of other conductive fabrics. It introduces appropriate oxygen-containing functional groups to achieve functionalization, and the treated fabric surface contains a large number of oxygen-containing functional groups such as hydroxyl and carboxyl groups, improving the fabric surface activity, increasing the number of active sites, and significantly enhancing the wettability of the fabric, which is beneficial for the chemical bonding between the fabric and the electrochromic film.

[0041] In some specific embodiments, in step S1, the flexible conductive fabric includes one of carbon cloth, conductive cloth, and silver-plated nylon cloth, preferably carbon cloth; when carbon cloth is used as the flexible conductive fabric, the impact on the fabric structure is minimal when ammonium sulfate pretreatment is applied, and the loss of mechanical properties is minimal.

[0042] In some specific embodiments, in steps S1 and S3, the cleaning process involves alternating ultrasonic treatment of the fabric with deionization and ethanol for 20 to 30 minutes, followed by drying in a drying oven at 50 to 70°C for 4 to 12 hours.

[0043] An inorganic-doped electrochromic fabric comprises a flexible conductive substrate and a WO3-MoO3 inorganic-doped electrochromic layer loaded on the surface of the flexible conductive substrate. The flexible conductive substrate and the WO3-MoO3 inorganic-doped electrochromic layer are chemically bonded together. This inorganic-doped electrochromic fabric has a large current value, with a maximum current value of not less than 5.5 mA. The electrochromic layer has a large number of electroactive sites on its surface, which is conducive to ion transfer during color change and improves the color switching rate. The coloring time is 3-6.5 s and the bleaching time is 4-8 s. Compared with a single-material electrochromic layer, its color switching time is significantly shortened and its performance is stable.

[0044] This invention uses an anhydrous tungsten chloride ethanol solution containing molybdenum pentachloride powder as a precursor solution to form a composite film of tungsten trioxide and molybdenum trioxide on the surface of a fabric. Compared with a single WO3 film, MoO3 exhibits stronger and more uniform light absorption in its electrochromic response in the colored state, and also has a better open-circuit memory effect. Therefore, by doping with MoO3, the optimized WO3 and MoO3 composite film possesses excellent electrical, optical, and mechanical properties, as well as fast optical response time and high coloring efficiency, making it suitable for applications in smart clothing and implantable displays.

[0045] Example 1

[0046] This embodiment provides a method for preparing inorganic doped electrochromic fabric, including the following steps:

[0047] S1. The carbon cloth with a size of 3×3cm was ultrasonically treated with deionized water and ethanol alternately for 20 minutes. The cleaned fabric was dried at 60℃ for 6 hours and then hydrophilically treated with ammonium sulfate solution to obtain pretreated carbon cloth.

[0048] The hydrophilic treatment method involves using the washed fabric as the positive electrode, a platinum electrode as the negative electrode, and an ammonium sulfate solution with a concentration of 1 mol / L as the electrolyte. The fabric is treated with a constant voltage of +5V for 10 minutes, then removed and washed twice alternately with ethanol and deionized water, and dried to obtain the pretreated fabric.

[0049] S2. Place 0.005 mol of tungsten chloride in 50 mL of anhydrous ethanol solvent and stir for 5 min to obtain an anhydrous ethanol solution of tungsten chloride. Add molybdenum pentachloride powder and stir evenly to obtain a precursor solution. In the precursor solution, the molar ratio of tungsten chloride to molybdenum pentachloride is 5:1.

[0050] S3. The pretreated carbon cloth from step S1 is vertically placed into a polytetrafluoroethylene liner and fixed. The precursor solution obtained in step S2 is poured in and sealed. The mixture is then placed in a stainless steel reactor for a high-temperature reaction at 200°C for 20 hours. After the reaction is complete, the fabric is removed and washed alternately with deionized water and anhydrous ethanol. It is then dried in a 60°C oven for 12 hours to obtain the inorganic doped electrochromic fabric.

[0051] Please see Figure 1 The image shown is a SEM image of the inorganic doped electrochromic fabric prepared in Example 1. As can be seen from the image, a dense MoO3 film is formed on the fiber surface, with WO3 particles attached to the film. The diameter of the WO3 particles ranges from 500 to 800 nm. The composite film of MoO3 and WO3 gives it excellent electrochromic properties.

[0052] Please see Figure 2 The figure shows the cyclic voltammetric performance test results of the inorganic doped electrochromic fabric prepared in Example 1. The curve shows the reduction peak of WO3 at -0.3V and the oxidation peak at 0.5V, indicating that the color change of the electrochromic fabric is mainly caused by the change in the redox state of the electrochromic material. The color of the fabric changes from blue-black to colorless as the voltage increases from -0.3V to 0.5V. As shown in the figure, the maximum current value of the electrochromic fabric is 6.12mA, and the current density remains unchanged after 20 cycles, indicating that its electrochromic performance is excellent.

[0053] Please see Figure 3 The figure shows the time-current curve of the inorganic-doped electrochromic fabric prepared in Example 1. The curve presents the color-changing time of the WO3-MoO3 inorganic-doped electrochromic fabric in the reduced and oxidized states. The figure shows that the coloring time is 5.2 s and the bleaching time is 7.2 s, exhibiting a relatively fast color switching rate. The rapid and sensitive color switching time of this fabric is attributed to the uniform MoO3 film formed on the fiber surface, which improves the fabric's conductivity and increases the binding sites of WO3, thereby increasing the H2O content. + The embedding and detachment rates of the electrochromic layer.

[0054] Examples 2-5

[0055] Examples 2-5 provide methods for preparing inorganic doped electrochromic fabrics. Compared with Example 1, the difference is that the molar ratio of tungsten chloride to molybdenum pentachloride is 10:1, 10:3, 5:2, and 2:1, respectively. The rest is roughly the same as in Example 1 and will not be repeated here.

[0056] Please see Figure 4 The image shown is a SEM image of the inorganic doped electrochromic fabric prepared in Example 2. As can be seen from the image, uneven WO3 nanoparticles are attached to the carbon fibers. Due to the low content of MoO3, the thin film attached to the carbon fiber surface is not obvious, and the WO3 particles cannot uniformly cover the MoO3 film.

[0057] Please see Figure 5 The image shown is a SEM image of the inorganic doped electrochromic fabric prepared in Example 3. As can be seen from the image, compared to the sample in Example 1, the film thickness formed on the fiber increases significantly with increasing MoO3 concentration. This leads to the aggregation of WO3 nanoparticles on the surface, forming large particle structures, which makes the sample inferior to Example 1 in subsequent electrochemical performance tests.

[0058] Please see Figure 6The image shows a SEM image of the inorganic doped electrochromic fabric prepared in Example 5. As can be seen from the image, the increased concentration of molybdenum pentachloride (WO3) leads to a large amount of MoO3 adhering to the fiber surface, forming a thick film that coats the fiber surface and exhibits cracks. This affects the stable bonding between the electrochromic layer and the fabric. Furthermore, the uneven distribution of WO3 particles affects the electrochromic properties of WO3.

[0059] Comparative Example 1

[0060] Comparative Example 1 provides a method for preparing an electrochromic fabric. The difference from Example 1 is that in step S2, the anhydrous ethanol solution of tungsten chloride was not mixed with molybdenum pentachloride powder. The rest is roughly the same as in Example 1 and will not be repeated here.

[0061] Please see Figure 7 The image shows a SEM image of the electrochromic fabric prepared in Comparative Example 1. As can be seen from the image, the fiber surface under these conditions is smoother due to the absence of a MoO3 film load. However, because of the lack of a MoO3 layer, the binding sites between WO3 and the fabric are reduced, and the resulting nanoparticles cannot uniformly and efficiently coat the fiber surface, leading to agglomeration and a significant reduction in the fabric's electrochromic ability.

[0062] Comparative Example 2

[0063] Comparative Example 2 provides a method for preparing an electrochromic fabric. The difference from Example 1 is that in step S2, molybdenum pentachloride powder is directly used instead of tungsten chloride dissolved in anhydrous ethanol as a precursor solution. The rest is roughly the same as in Example 1 and will not be repeated here.

[0064] Comparative Example 3

[0065] Comparative Example 3 provides a method for preparing an electrochromic fabric. The difference from Example 1 is that in step S1, ammonium sulfate solution was not used to treat the fabric for hydrophilicity. The rest is roughly the same as Example 1 and will not be repeated here.

[0066] Comparative Example 4

[0067] Comparative Example 4 provides a method for preparing an electrochromic fabric. The difference from Example 1 is that in step S1, a sodium hydroxide solution of the same concentration is used instead of an ammonium sulfate solution to perform hydrophilic treatment on the fabric. The rest is roughly the same as in Example 1, and will not be repeated here.

[0068] Comparative Example 5

[0069] Comparative Example 5 provides a method for preparing an electrochromic fabric. The difference from Example 1 is that in step S1, the concentration of the ammonium sulfate solution is 3 mol / L. The rest is roughly the same as in Example 1 and will not be repeated here.

[0070] Comparative Example 6

[0071] Comparative Example 6 provides a method for preparing an electrochromic fabric. The difference from Example 1 is that the hydrophilic treatment time in step S1 is 15 minutes. The rest is roughly the same as in Example 1 and will not be repeated here.

[0072] The electrochromic fabrics of Examples 1-5 and Comparative Examples 1-6 were tested for electrochromic properties and mechanical properties, and the results are shown in the table below.

[0073] Table 1. Performance test results of electrochromic fabrics in Examples 1-5 and Comparative Examples 1-6

[0074] Maximum current value (mA) Coloring time (s) Bleaching time (s) Fracture strength (N / 25mm) Example 1 6.00 5.2 7.2 1612 Example 2 5.83 6.0 7.8 1602 Example 3 5.87 4.2 7.5 1610 Example 4 5.96 5.8 7.9 1605 Example 5 6.02 6.3 8.0 1593 Comparative Example 1 4.20 6.5 8.4 1595 Comparative Example 2 4.84 6.3 8.1 1609 Comparative Example 3 3.23 8.0 10.2 1600 Comparative Example 4 3.65 6.8 8.3 1420 Comparative Example 5 3.27 7.4 8.9 1459 Comparative Example 6 3.98 7.1 8.5 1487

[0075] As shown in Table 1, and in Examples 1-5, with the increase of the MoCl5 ratio, the thickness of the composite film obtained on the surface of the electrochromic fabric increases, and its maximum current value also gradually increases. However, when the film thickness increases to a certain value, it is not conducive to the penetration of ions in the electrochromic layer, and its color change / coloring time also begins to increase. When the fabric is loaded with too much material, its tensile strength begins to decrease. As shown in Comparative Examples 1-2, when molybdenum pentachloride powder is not added, the binding sites of WO3 with the fabric decrease, and the formed nanoparticles cannot be uniformly and efficiently coated on the fiber surface, forming agglomerates, which significantly reduces the electrochromic ability of the fabric. In Comparative Example 2, only molybdenum pentachloride is used as the electrochromic layer, and its maximum current value decreases, while the coloring time and bleaching time are also inferior to those in Example 1.

[0076] As can be seen from Comparative Examples 3 to 6, by changing the hydrophilic treatment conditions, it was found that increasing the treatment time, increasing the solution concentration, or using sodium hydroxide solution for treatment all had adverse effects on the strength of carbon fibers, significantly reducing the mechanical strength and maximum current value of carbon fibers. However, the fabrics that were not hydrophilically treated had fewer oxides growing on their surface, a very small maximum current value, and increased coloring and bleaching time resulted in less obvious color change and poorer electrochromic performance.

[0077] In summary, this invention provides an inorganic doped electrochromic fabric and its preparation method. First, the fabric is subjected to hydrophilic treatment with ammonium sulfate solution. Then, the pretreated fabric is placed in an anhydrous tungsten chloride ethanol solution containing molybdenum pentachloride powder for high-temperature reaction. After the reaction is completed, the fabric is taken out, washed and dried multiple times to obtain the inorganic doped electrochromic fabric. This invention employs ammonium sulfate solution to perform constant potential treatment on fabrics, promoting carbon stripping in carbon cloth or enabling electron transfer and ion exchange in the metal layers on the surfaces of other conductive fabrics. It introduces appropriate oxygen-containing functional groups to achieve functionalization, resulting in a fabric surface rich in hydroxyl and carboxyl groups, enhancing surface activity and increasing active sites, which facilitates chemical bonding between the fabric and the electrochromic film. Tungsten chloride is used as the tungsten source, eliminating the need for acid adjustment and avoiding damage to the fabric structure. The synthesized tungsten trioxide consists of uniform small-sized nanospheres, requiring no morphology control. Molybdenum pentachloride is used as a precursor for high-temperature reaction with tungsten chloride. Because molybdenum oxide is more reactive than tungsten oxide, and its bonding strength with the fabric is superior, molybdenum oxide first nucleates on the fabric surface, forming a MoO3 layer. This provides sites for the nucleation and growth of WO3, allowing WO3 to gradually grow and adhere, thus forming a stable composite electrochromic film layer, giving the fabric excellent electrochromic properties. The inorganic doped electrochromic fabric prepared by this method has excellent electrical, optical and mechanical properties, as well as fast optical response time and high coloring efficiency. With the limited process and parameters, it is suitable for application in fields such as smart clothing and implantable displays.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an inorganically doped electrochromic fabric, characterized in that, Includes the following steps: S1. The flexible conductive fabric is cleaned and subjected to hydrophilic treatment with ammonium sulfate solution to obtain a pretreated fabric. The hydrophilic treatment method is to use the cleaned flexible conductive fabric as the positive electrode, a platinum electrode as the negative electrode, ammonium sulfate solution as the electrolyte, and constant potential treatment to obtain the pretreated fabric. The concentration of the ammonium sulfate solution is 1-2 mol / L, and the constant potential treatment is performed with a constant voltage of +5V for 5-10 minutes. S2. Prepare an anhydrous ethanol solution of tungsten chloride, add molybdenum pentachloride powder, and stir until homogeneous to obtain a precursor solution; in the precursor solution, the molar ratio of tungsten chloride to molybdenum pentachloride is 10:(1-5). S3. Place the pretreated fabric from step S1 into the precursor solution obtained in step S2 and carry out a high-temperature reaction. After the reaction is completed, take out the fabric, wash it several times and dry it to obtain an inorganic doped electrochromic fabric. The high-temperature reaction process is as follows: the reaction temperature is 100-200℃ and the reaction time is 20-24h.

2. The method for preparing inorganic doped electrochromic fabric according to claim 1, characterized in that, The method for preparing the anhydrous ethanol solution of tungsten chloride is to place 0.005 to 0.010 mol of tungsten chloride in 50 to 100 mL of anhydrous ethanol solvent and stir for 3 to 5 minutes.

3. The method for preparing inorganic doped electrochromic fabric according to claim 1, characterized in that, In step S1, the flexible conductive fabric includes a conductive cloth.

4. The method for preparing inorganic doped electrochromic fabric according to claim 3, characterized in that, The flexible conductive fabric is carbon cloth.

5. The method for preparing inorganic doped electrochromic fabric according to claim 1, characterized in that, In steps S1 and S3, the cleaning process involves alternating ultrasonic treatment of the fabric with deionization and ethanol for 20-30 minutes, followed by drying in a drying oven at 50-70°C for 4-12 hours.

6. An inorganic doped electrochromic fabric prepared by the preparation method according to any one of claims 1 to 5, characterized in that, The inorganic doped electrochromic fabric includes a flexible conductive substrate and a WO3-MoO3 inorganic doped electrochromic layer loaded on the surface of the flexible conductive substrate. The flexible conductive substrate and the WO3-MoO3 inorganic doped electrochromic layer are bonded together by chemical bonding.

7. The inorganic doped electrochromic fabric according to claim 6, characterized in that, The maximum current value of the inorganic doped electrochromic fabric is not less than 5.5mA, the coloring time is 3 to 6.5s, and the bleaching time is 4 to 8s.

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