A tungsten oxide nanoparticle, a gel electrolyte, and a preparation method and application thereof

Abstract

This invention belongs to the field of photochromic nanomaterials, and relates to tungsten oxide nanoparticles, a gel electrolyte, their preparation method, and applications. It provides hydrated tungsten oxide prepared by a chemical reaction in solution without drying. The hydrated tungsten oxide is added to water and dispersed evenly, then ethylene glycol is added, making the volume ratio of water to ethylene glycol 2–10:4–10. After sealing, the mixture is heated to 70–110°C and reacted for 15–45 min to obtain the final product. The dispersion concentration after the reaction is 0.5–8 mg / mL. The tungsten oxide nanoparticles prepared by this invention exhibit photochromic properties, and the preparation method is simple, low-cost, and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of photochromic nanomaterials, and relates to tungsten oxide nanoparticles, gel electrolytes, their preparation methods and applications. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Applications of WO3 photochromic effect include photochromic smart windows, photochromic nano inks, WO3 hydrophobic coatings, and WO3 photochromic pigments.

[0004] The inventors discovered that current coloring / fading of WO3 is limited to ultraviolet light irradiation. Researchers are working to broaden the spectral range through structural and geometric control, elemental doping, or heterostructures, extending its photoresponse to the visible light region (400–800 nm) and even the entire solar radiation range. While these strategies can partially improve photochromic performance, they still face challenges such as high cost (Au or Ag / WO3 composites, CdS / WO3 composites) and complex preparation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide tungsten oxide nanoparticles, gel electrolytes, their preparation methods, and applications. The tungsten oxide nanoparticles prepared by the present invention exhibit photochromic properties, and their preparation method is simple, low-cost, and environmentally friendly.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] On the one hand, a method for preparing tungsten oxide nanoparticles provides hydrated tungsten oxide prepared by chemical reaction in solution without drying. The hydrated tungsten oxide is added to water and dispersed evenly, and then ethylene glycol is added so that the volume ratio of water to ethylene glycol is 2-10:4-10. After sealing, the mixture is heated to 70-110°C and reacted for 15-45 minutes to obtain the nanoparticles.

[0008] The dispersion concentration after the reaction is 0.5–8 mg / mL.

[0009] Hydrated tungsten oxide prepared by chemical reaction and not dried has a surface rich in hydroxyl groups, which can be uniformly dispersed in water. However, after drying, the surface hydroxyl groups of hydrated tungsten oxide are destroyed, thus making it impossible to disperse uniformly in water. Uniformly dispersing hydrated tungsten oxide in water is a prerequisite for the preparation of photochromic tungsten oxide nanoparticles in this invention.

[0010] Then, in this invention, hydrated tungsten oxide is dispersed in water, and ethylene glycol is added. The mixture is then heated under sealed conditions. First, this process enables ethylene glycol to coordinate with tungsten oxide, providing the protons required for photochromism, while simultaneously lowering the Fermi level on the tungsten oxide surface, thus giving the prepared tungsten oxide nanoparticles photochromic properties. Second, the sealed heating reaction prevents water evaporation from the reaction system, ensuring a transparent solution and preventing the aggregation of tungsten oxide nanoparticles, which would lead to the loss of photochromic properties. Third, if the reaction time is too long or the concentration is too high, the particle size of the tungsten oxide nanoparticles will increase, thus preventing them from exhibiting photochromic properties.

[0011] On the other hand, a tungsten oxide nanoparticle is obtained by the above-described method for preparing tungsten oxide nanoparticles.

[0012] Thirdly, a method for preparing a gel electrolyte is provided, wherein the material after the reaction of the above-mentioned tungsten oxide nanoparticle preparation method is used as a color-changing ink, zinc perchlorate and lithium perchlorate are added to the color-changing ink to obtain a conductive salt solution, and acrylamide monomer, crosslinking agent, initiator and crosslinking agent auxiliary are added to the conductive salt solution, and after being mixed evenly, it is thermally cured to obtain the gel electrolyte.

[0013] Fourthly, a gel electrolyte is obtained by the above-described method for preparing gel electrolytes.

[0014] Fifthly, the application of the aforementioned gel electrolyte in a color-changing smart window.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. The WO3 photochromic ink provided by this invention has a simplified preparation process and excellent photochromic properties. This invention utilizes freshly prepared, undried hydrated WO3 nanoparticles, employing a solution method under heating conditions to coordinate ethylene glycol with WO3. The hydroxyl groups on the ethylene glycol provide the protons required for photochromism in WO3. Simultaneously, during the diffusion process, the protons lower the Fermi level on the WO3 surface, thereby increasing the absorbance of the material and enhancing the sensitivity of WO3 photochromism.

[0017] 2. Compared to traditional electrochromic materials that only change color under ultraviolet light, the WO3 photochromic ink prepared in this invention can achieve a rapid photochromic response under sunlight. Under simulated sunlight intensity, a light response is generated after 60 seconds, and the color change is complete after 900 seconds. Simultaneously, the added ethylene glycol solvent inhibits the grain growth of WO3 nanoparticles, which further reduces the size of the WO3 nanoparticles during the reaction process, resulting in ultrafine WO3 nanoparticles.

[0018] 3. The photochromic WO3 gel electrolyte prepared in this invention has high transmittance (~90%) and high color contrast (~90%). It can also achieve the photochromic effect under sunlight, and its light response is rapid, producing a light response after 30 seconds of light exposure. It can block visible and near-infrared light after 600 seconds of light exposure. Furthermore, this gel electrolyte also possesses high ionic conductivity and excellent tensile properties.

[0019] 4. The photochromic WO3 ink of this invention has a simple preparation process, uses inexpensive and readily available raw materials, and is non-toxic and harmless to the environment. Furthermore, the photochromic WO3 gel electrolyte prepared using this ink as a raw material possesses rapid light response capability, excellent mechanical properties, and a simple manufacturing and operation process, showing broad application prospects in information encoding, smart anti-glare glasses, and photochromic smart windows. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 A schematic diagram (a) of the preparation of WO3 photochromic ink by the electrode oxidation method of the present invention; and an XRD pattern (b) of the WO3 photochromic material.

[0022] Figure 2 The morphology of the prepared WO3 photochromic material is shown in (a) and (b) after anodic oxidation.

[0023] Figure 3 A photograph of the photochromic WO3 ink prepared in Example 1 undergoing photochromic changes under sunlight.

[0024] Figure 4 The absorbance curves of the photochromic WO3 ink prepared in Example 1 under different light exposure times.

[0025] Figure 5 The absorbance curves of the photochromic WO3 ink prepared in Example 1 after irradiation for different times after the removal of ethylene glycol.

[0026] Figure 6 The transmittance and optical photograph of the photochromic WO3 gel electrolyte prepared in Example 1.

[0027] Figure 7 The images show the photochromic WO3 gel electrolyte prepared in Example 1 undergoing photochromic changes under sunlight. a represents the initial state, b represents 30s, c represents 60s, d represents 180s, e represents 300s, f represents 420s, and g represents 600s.

[0028] Figure 8 The change in transmittance spectrum of the photochromic WO3 gel electrolyte prepared in Example 1 under sunlight.

[0029] Figure 9 The image shows a tensile photograph of the photochromic WO3 gel electrolyte prepared in Example 2. a is the initial image, and b is the tensile image.

[0030] Figure 10 The image shows the ionic conductivity test results of the photochromic WO3 gel electrolyte prepared in Example 2. The inset is a photograph of the gel electrolyte illuminating an LED bulb.

[0031] Figure 11 The change in transmittance spectrum of the photochromic WO3 gel electrolyte prepared in Example 3 under sunlight.

[0032] Figure 12 Scanning electron microscope (SEM) images of the photochromic ink prepared for Comparative Example 1 (a); photographs of the photochromic ink prepared for Comparative Example 1 (b); and photographs of the photochromic gel electrolyte prepared for Comparative Example 2 (c). Detailed Implementation

[0033] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, 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 invention pertains.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] Given that existing methods for preparing photochromic WO3 suffer from high costs and complex preparation processes, this invention proposes a method for preparing tungsten oxide nanoparticles, a gel electrolyte, and their applications.

[0036] A typical embodiment of the present invention provides a method for preparing tungsten oxide nanoparticles. The method involves providing hydrated tungsten oxide prepared by a chemical reaction in solution without drying. The hydrated tungsten oxide is added to water and dispersed evenly. Then, ethylene glycol is added, making the volume ratio of water to ethylene glycol 2–10:4–10. After sealing, the mixture is heated to 70–110°C and reacted for 15–45 minutes to obtain the final product.

[0037] The dispersion concentration after the reaction is 0.5–8 mg / mL.

[0038] In this invention, the method for preparing hydrated tungsten oxide through a chemical reaction in solution can be anodizing, hydrothermal, etc.

[0039] In some embodiments, hydrated tungsten oxide is prepared by anodizing. Studies have shown that the anodizing method is simpler and more effective in obtaining hydrated tungsten oxide with a surface rich in hydroxyl groups.

[0040] In one or more embodiments, the anodic oxidation process is as follows: a tungsten sheet is placed in a hydrochloric acid electrolyte, a DC bias voltage of 30–60V is applied to the tungsten sheet, and the treatment time is 10–30 minutes. The DC bias voltage is preferably 40–50V, more preferably 40–45V. The treatment time is preferably 20–30 minutes.

[0041] In one or more embodiments, after the anodic oxidation process, the precipitate is obtained by washing with water and centrifugation, which is hydrated tungsten oxide. The centrifugation speed is 8000-12000 r / min, the time is 5-15 min, and the number of washing cycles is 2-3.

[0042] In one or more embodiments, the tungsten sheet is polished with sandpaper before use, and then ultrasonically cleaned with deionized water, acetone, ethanol and deionized water respectively.

[0043] In some embodiments, hydrated tungsten oxide is added to water and ultrasonically dispersed.

[0044] In some embodiments, the mixture is sealed and heated to 92–98°C. The reaction time is 25–35 minutes.

[0045] In some embodiments, heating is performed using an oil bath. The stirring speed for oil bath heating is 500–800 r / min, preferably 800 r / min.

[0046] In another embodiment of the present invention, tungsten oxide nanoparticles are provided, which are obtained by the above-described method for preparing tungsten oxide nanoparticles.

[0047] In some embodiments, the particle size of the tungsten oxide nanoparticles is 3–4 nm.

[0048] In a third embodiment of the present invention, a method for preparing a gel electrolyte is provided, wherein the material after the reaction of the above-mentioned tungsten oxide nanoparticle preparation method is used as a color-changing ink, zinc perchlorate and lithium perchlorate are added to the color-changing ink to obtain a conductive salt solution, and acrylamide monomer, crosslinking agent, initiator and crosslinking agent auxiliaries are added to the conductive salt solution, and after being mixed evenly, it is thermo-cured to obtain the gel electrolyte.

[0049] In some embodiments, the concentration of zinc perchlorate in the conductive salt solution is 0.2–1 mol / L, preferably 0.2–0.3 mol / L.

[0050] In some embodiments, the concentration of lithium perchlorate in the conductive salt solution is 0.8–2 mol / L, preferably 0.9–1.1 mol / L.

[0051] In some embodiments, the mass ratio of acrylamide monomer to the volume of conductive salt solution is 0.2–0.5 g:1 mL, more preferably 0.3–0.4 g:1 mL.

[0052] In some embodiments, the mass of the crosslinking agent is 0.5 to 1% of the mass of the acrylamide monomer, and the mass of the crosslinking agent auxiliaries is 0.05 to 0.2% of the mass of the acrylamide monomer. Studies have shown that under these conditions, the surface of the prepared gel electrolyte can remain smooth. When excessive amounts of crosslinking agent auxiliaries are added, the internal stress generated due to different solidification rates can cause wrinkling of the gel surface and affect the permeability of the final film.

[0053] In some embodiments, the crosslinking agent is N,N'-methylenebisacrylamide. Studies have shown that using this crosslinking agent yields better results.

[0054] In some embodiments, the crosslinking agent is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0055] In some embodiments, the initiator is ammonium persulfate. Ammonium persulfate is more uniformly dispersed in the reaction system, which is beneficial to the uniformity of crosslinking and curing, and avoids the generation of internal stress caused by uneven dispersion.

[0056] In some embodiments, the thermosetting temperature is 30–50°C and the thermosetting time is 15–60 min.

[0057] A fourth embodiment of the present invention provides a gel electrolyte obtained by the above-described method for preparing gel electrolytes.

[0058] The fifth embodiment of the present invention provides an application of the above-mentioned gel electrolyte in a color-changing smart window.

[0059] In some embodiments, the color-changing smart window includes photochromic properties. It may also include electrochromic properties.

[0060] In some embodiments, the color-changing smart window includes two pieces of glass arranged side by side, with a photochromic layer disposed between the two pieces of glass, and the photochromic layer is made of the aforementioned gel electrolyte.

[0061] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0062] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0063] Example 1

[0064] A method for preparing a WO3 hydrogel electrolyte with photochromic properties includes the following steps:

[0065] (1) Preparation of photochromic WO3 materials

[0066] After polishing the high-purity tungsten sheet (0.08*20*40mm) flat, it was ultrasonically washed for 15 minutes each time with deionized water, acetone, ethanol, and then deionized water. Two tungsten sheets were then placed parallel to each other in a 0.02M hydrochloric acid electrolyte solution, with a distance of approximately 4cm between them. Figure 1 a) A DC bias voltage of 40V was applied to one end of two tungsten sheets for 20 minutes to obtain a yellow hydrated tungsten oxide solution.

[0067] The hydrated tungsten oxide solution was washed with deionized water and centrifuged at 10,000 rpm for 10 minutes to remove excess hydrochloric acid. This process was repeated six times to obtain a pale yellow precipitate.

[0068] The pale yellow precipitate was dispersed by ultrasonication using 4 mL of deionized water for 10 min.

[0069] Add 8 mL of ethylene glycol to the dispersed yellow solution.

[0070] The mixed solution was sealed and transferred to an oil bath for heating and stirring at a temperature of 95°C for 30 minutes.

[0071] During the reaction, the solution color gradually changes from yellow to transparent, and finally a uniformly dispersed transparent photochromic ink is obtained with a dispersion concentration of 2.5 mg / mL.

[0072] (2) Preparation of stretchable photochromic polyacrylamide (PAM) gel electrolyte

[0073] Zinc perchlorate (0.37238 g) and lithium chloride trihydrate (0.8022 g) were dissolved in 5 ml of WO3 photochromic ink and stirred at room temperature for 30 min at a speed of 800 r / min to obtain a clear and transparent colloid.

[0074] Subsequently, 1.6 g of acrylamide monomer was added to the transparent colloid, followed by the crosslinking agent N,N'-methylenebisacrylamide (MBAA, 13 mg) and the initiator ammonium persulfate (26 mg). The mixture was magnetically stirred for 1 h at a speed of 1000 r / min to obtain the transparent colloid. Then, 3 μL of N,N,N',N'-tetramethylethylenediamine (TEMED) was added to the above solution, and the mixture was magnetically stirred for 3 min to mix thoroughly.

[0075] The uniformly mixed solution was transferred to a glass mold and heated at 60°C for 20 minutes to form a polyacrylamide (PAM) gel electrolyte.

[0076] The morphology and properties of the obtained photochromic WO3 material were characterized:

[0077] The transparent photochromic WO3 ink and the photochromic polyacrylamide (PAM) gel film prepared in steps (1) and (2) were placed under a uniform xenon lamp light source system with an illumination distance of 15 cm, a current of 15 A, and a voltage of 15 V to simulate the intensity of sunlight. Simultaneously, the light source system was coupled with a UV-Vis spectrometer to characterize the photochromic properties.

[0078] The structure of the photochromic WO3 material in this embodiment was determined by X-ray diffraction, such as... Figure 1 As shown in b, the XRD pattern reveals that the obtained material is amorphous WO3. The morphology of the material was observed using a transmission electron microscope, as shown below. Figure 2 As shown in figure a, the morphology of amorphous WO3 consists of ultra-small nanoparticles with a particle size of approximately 3-4 nm. This is completely different from the morphology of hydrated tungsten oxide prepared after anodizing. Figure 2 b) indicates that ethylene glycol promoted the dispersion of WO3 and inhibited the grain growth of WO3 nanoparticles, which further reduced the size of WO3 nanoparticles during the reaction, resulting in ultra-small WO3 nanoparticles. When irradiated with a xenon lamp source for different durations, the transparent WO3 ink exhibited different color depths; with increasing irradiation time, the ink color changed from colorless and transparent to deep blue. Figure 3 ).

[0079] The absorbance of photochromic WO3 ink as a function of light exposure time was tested using a UV-Vis spectrometer. The absorbance curves for different colors are shown below. Figure 4 As shown, the absorbance of the ink gradually increases with increasing illumination time. Meanwhile, as a control group, ethylene glycol in the photochromic ink was washed away using a 100-day dialysis membrane, and the photochromic absorbance was then measured. The results are as follows... Figure 5As shown, inks without ethylene glycol cannot produce photochromic phenomena, indicating that ethylene glycol plays a role in providing protons and increasing the sensitivity of WO3 photochromism during the electrochromic process.

[0080] The initial transmittance of the photochromic WO3 hydrogel electrolyte in this embodiment was tested using a UV-Vis spectrometer. Figure 6 As shown, the transmittance of the gel electrolyte in the visible light range reaches over 90%.

[0081] The color change of WO3 hydrogel electrolyte when exposed to light for different durations using a xenon lamp source is as follows: Figure 7 As shown. The photochromic performance of the photochromic WO3 hydrogel electrolyte was tested using a UV-Vis spectrometer. Its transmittance in the visible light range is shown in the figure. Figure 8 As shown, the transmittance gradually decreases with increasing illumination time, with the lowest transmittance being about 5%, demonstrating excellent light modulation capability.

[0082] Example 2

[0083] A method for preparing a stretchable photochromic WO3 hydrogel electrolyte includes the following steps:

[0084] (1) The preparation of WO3 nanoparticles is the same as in Example 1.

[0085] (2) Preparation of stretchable photochromic polyacrylamide (PAM) gel electrolyte:

[0086] Zinc perchlorate (0.74476 g) and lithium chloride trihydrate (3.2088 g) were dissolved in 10 ml of WO3 photochromic ink and stirred at room temperature for 30 min at a speed of 800 r / min to obtain a clear and transparent colloid.

[0087] Subsequently, acrylamide monomer (3.2 g) was added to the transparent colloid, followed by the crosslinking agent N,N'-methylenebisacrylamide (MBAA, 26 mg) and the initiator ammonium persulfate (52 mg). The mixture was magnetically stirred for 1 h at a speed of 1000 r / min to obtain a transparent colloid. Then, 5 μL of N,N,N',N'-tetramethylethylenediamine (TEMED) was added to the above solution, and the mixture was magnetically stirred for 5 min to mix thoroughly.

[0088] The uniformly mixed solution was transferred to a petri dish with a diameter of 9 cm and heated at 60 °C for 20 minutes to form a polyacrylamide (PAM) gel electrolyte. Then, the gel membrane was cut into rectangles (10 mm × 30 mm) to obtain the photochromic gel electrolyte membrane.

[0089] The conductivity and mechanical properties of the obtained gel electrolyte membrane were characterized:

[0090] like Figure 9 As shown, increasing the content of crosslinking agent and initiator allows the gel electrolyte membrane to withstand approximately 100% tensile deformation without failure. The impedance spectrum of the electrolyte membrane was measured using an electrochemical workstation. Figure 10 Due to the excellent adhesion of the gel electrolyte, the electrolyte and electrode can be in close contact, resulting in a low charge transfer resistance in the electrolyte membrane. At room temperature, the internal resistance of the electrolyte membrane is only 4.28 Ω. According to the formula for calculating ionic conductivity, σ = L / (R*S), where L and S represent the thickness (cm) and area (cm²) of the gel membrane, respectively. 2 R is the impedance spectrum. Figure X The intercept on the axis. Therefore, the ionic conductivity of the gel membrane is σ = 9.34 × 10⁻⁶. -2 S m -1 It can connect to the circuitry of commercial LED bulbs.

[0091] Example 3

[0092] A method for preparing a stretchable photochromic WO3 hydrogel electrolyte includes the following steps:

[0093] (1) Preparation of WO3 nanoparticles

[0094] After polishing the high-purity tungsten sheet (0.08*20*40mm) flat, it was ultrasonically washed with deionized water, acetone, ethanol and deionized water for 15 minutes in sequence. Two tungsten sheets were placed parallel to each other with a spacing of 4cm in a 0.02M hydrochloric acid electrolyte and a DC bias voltage of 40V was applied for 20 minutes to obtain a yellow hydrated tungsten oxide solution.

[0095] The hydrated tungsten oxide solution was washed with deionized water and centrifuged at 10,000 rpm for 10 min to remove excess hydrochloric acid. This process was repeated six times to obtain a pale yellow precipitate.

[0096] The pale yellow precipitate was dispersed by ultrasonication using 2 mL of deionized water for 5 min.

[0097] Add 4 mL of ethylene glycol to the dispersed yellow solution.

[0098] The mixed solution was sealed and transferred to an oil bath for heating and stirring at a temperature of 95°C for 30 minutes.

[0099] During the reaction, the solution color gradually changed from yellow to translucent light yellow, and finally a uniformly dispersed photochromic ink was obtained with a dispersion concentration of 5 mg / mL.

[0100] (2) The preparation of stretchable photochromic polyacrylamide (PAM) gel electrolyte is the same as in Example 1.

[0101] The photochromic properties of the gel electrolyte were improved due to the increased content of photochromic WO3 material. The photochromic performance was tested using a UV-Vis spectrometer. Its transmittance in the visible light range is as follows: Figure 11 As shown, the minimum transmittance (approximately 5%) is reached after about 180 seconds of illumination.

[0102] Example 4:

[0103] The difference from Example 1 is that the bias voltage applied in step (1) is adjusted to 50V for 30 minutes. A transparent and uniform photochromic WO3 ink with photochromic properties can be prepared.

[0104] Comparative Example 1

[0105] The difference from Example 1 is that the bias voltage applied in step (1) is adjusted to 50V for 30 minutes, and the mixed solution is heated and stirred in an oil bath for 60 minutes at a temperature of 95°C. Because the stirring time is too long, the particle size continuously increases and agglomerates. Figure 12 a). With the other steps remaining unchanged, this resulted in the following: Figure 12 The bright yellow solution shown in b cannot be used to prepare transparent and uniform photochromic WO3 ink, and therefore has no photochromic properties.

[0106] Comparative Example 2

[0107] The difference from Example 1 is that the amount of N,N,N',N'-tetramethylethylenediamine (TEMED) crosslinking aid added in step (2) is increased to 20 μL, while the other steps remain unchanged.

[0108] like Figure 12 As shown in c, the gel film prepared in this comparative example experiences internal stress due to different solidification rates during the thermosetting process, which causes wrinkling on the gel surface and affects the transmittance of the final film.

[0109] Application example: WO3 Smart Window with dual photochromic and electrochromic responses:

[0110] The preparation steps are as follows:

[0111] (1) Component assembly

[0112] Cleaning: Take two 5×5cm pieces 2 The ITO glass was ultrasonically cleaned with deionized water, acetone, ethanol and deionized water for 15 minutes in sequence, and then dried with nitrogen for later use.

[0113] Electrochromic WO3 film formation: WO3 electrodeposition solution was prepared by dissolving tungsten powder in hydrogen peroxide. An electrochromic WO3 film with an area of ​​2 × 2 cm was then prepared on ITO glass by electrodeposition. 2 ;

[0114] Assembly: Apply 1cm wide conductive copper tape around the perimeter of a prepared ITO glass sheet and press it firmly. Then, apply two layers of 3M transparent double-sided tape to the conductive copper tape, ensuring the tape completely covers the copper tape without contacting the electrolyte. Cut the prepared photochromic WO3 gel electrolyte membrane into 3×3cm pieces. 2 Cut a square shape and attach it to one side of the WO3 electrochromic layer, ensuring complete coverage. Cut out a zinc foil frame, ensuring that when the zinc foil frame is attached to the double-sided tape on the glass, 3-5mm of the edges protrude inwards and contact the gel electrolyte, without obstructing the WO3 electrochromic layer. Apply two more layers of 3M transparent double-sided tape around the zinc foil frame. Finally, cover it with a piece of quartz glass and press the two pieces of glass together to form the electrochromic device.

[0115] Compaction: Place the device under a heavy object and compact it for 4-6 days;

[0116] (3) Implementation of the dual-response WO3 smart window function

[0117] By utilizing a gel electrolyte with photochromic properties, this smart window can achieve electrolyte coloration under strong light, passively reducing the transmittance of visible light and thus reducing the light intensity entering the room. At the same time, the WO3 electrochromic layer can actively adjust the transmittance of visible light through an applied voltage, and its synergistic effect with the gel electrolyte can also achieve a completely "dark" state for the smart window.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a gel electrolyte, characterized in that, Hydrated tungsten oxide prepared by chemical reaction in solution and not dried is provided. The hydrated tungsten oxide is added to water and dispersed evenly. Then ethylene glycol is added so that the volume ratio of water to ethylene glycol is 2~10:4~10. After sealing, it is heated to 92~98 °C and reacted for 15~45 min. The reacted material is used as a color-changing ink. Zinc perchlorate and lithium perchlorate are added to the color-changing ink to obtain a conductive salt solution. Acrylamide monomer, crosslinking agent, initiator and crosslinking agent auxiliaries are added to the conductive salt solution. After mixing evenly, it is thermo-cured to obtain the final product. The reacted material contains tungsten oxide nanoparticles; the dispersion concentration after the reaction is 0.5~8 mg / mL. Hydrated tungsten oxide was prepared by anodizing. The anodizing process was as follows: tungsten sheet was placed in hydrochloric acid electrolyte, a DC bias voltage of 30-60 V was applied to the tungsten sheet, and the treatment was carried out for 10-30 min. The mass of the crosslinking agent is 0.05~0.2% of the mass of the acrylamide monomer.

2. The method for preparing gel electrolyte as described in claim 1, characterized in that, The DC bias voltage is 40~50 V.

3. The method for preparing the gel electrolyte as described in claim 2, characterized in that, The DC bias voltage is 40~45 V.

4. The method for preparing the gel electrolyte as described in claim 1, characterized in that, The processing time is 20-30 minutes.

5. The method for preparing the gel electrolyte as described in claim 1, characterized in that, The reaction time is 25~35 min.

6. The method for preparing the gel electrolyte as described in claim 1, characterized in that, The particle size of tungsten oxide nanoparticles is 3~4 nm.

7. The method for preparing the gel electrolyte as described in claim 1, characterized in that, In conductive salt solutions, the concentration of zinc perchlorate is 0.2~1 mol / L; Alternatively, in the conductive salt solution, the lithium perchlorate concentration is 0.8~2 mol / L; Alternatively, the mass ratio of acrylamide monomer to the volume of conductive salt solution is 0.2~0.5 g:1 mL; Alternatively, the mass of the crosslinking agent is 0.5 to 1% of the mass of the acrylamide monomer.

8. The method for preparing the gel electrolyte as described in claim 7, characterized in that, In the conductive salt solution, the concentration of zinc perchlorate is 0.2~0.3 mol / L.

9. The method for preparing the gel electrolyte as described in claim 7, characterized in that, In the conductive salt solution, the concentration of lithium perchlorate is 0.9~1.1 mol / L.

10. The method for preparing the gel electrolyte as described in claim 7, characterized in that, The mass ratio of acrylamide monomer to the volume of conductive salt solution is 0.3~0.4 g:1 mL.

11. The method for preparing the gel electrolyte as described in claim 7, characterized in that, The crosslinking agent is N,N'-methylenebisacrylamide; Alternatively, the crosslinking agent is N,N,N',N'-tetramethylethylenediamine; Alternatively, the initiator may be ammonium persulfate; Alternatively, the heat curing temperature is 30~50℃, and the heat curing time is 15~60min.

12. A gel electrolyte, characterized in that, It is obtained by the preparation method of the gel electrolyte according to any one of claims 1 to 11.

13. The application of the gel electrolyte of claim 12 in a color-changing smart window.

14. The application of the gel electrolyte as described in claim 13 in a color-changing smart window, characterized in that, The color-changing smart window includes a photochromic layer; Alternatively, the color-changing smart window may include two pieces of glass arranged side by side, with a photochromic layer disposed between the two pieces of glass, and the material of the photochromic layer being the gel electrolyte.

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