Electrochromic element and preparation method of electrolyte layer of electrochromic element

Abstract

The invention provides an electrochromic element. The electrochromic element comprises a first conductive layer, an electrochromic layer, an electrolyte layer, an ion storage layer and a second conductive layer which are sequentially stacked, the first conductive layer and the second conductive layer are used for receiving external electric power to form a voltage difference; the electrochromism layer is used for receiving electrons in the electrolyte layer to realize electrochromism; wherein the electrolyte layer comprises indium tin oxide nanoparticles which are uniformly arranged. The electrochromic element provided by the invention is beneficial to improving the light transmittance. The invention further provides a preparation method of the electrolyte layer of the electrochromic element.

Description

Technical Field

[0001] This application relates to an electrochromic element and a method for preparing an electrolyte layer of an electrochromic element. Background Art

[0002] Common electrochromic elements generally include an electrochromic layer, an electrolyte layer, and an ion storage layer arranged in layers. Under the action of an electric field, electrons in the electrolyte layer migrate to the electrochromic layer, and ions migrate to the ion storage layer. After the electron migration, the electrochromic layer forms a colored state, that is, the color of the electrochromic layer changes. However, the refractive indices of the electrochromic layer and the ion storage layer are usually much higher than that of the electrolyte layer. When light passes through the electrochromic layer, the electrolyte layer, and the ion storage layer in sequence, due to the large refractive index difference, the interlayer reflectivity is high, affecting the transmittance of the electrochromic element. Summary of the Invention

[0003] Based on this, it is necessary to provide an electrochromic element with high transmittance.

[0004] On the one hand, this application provides an electrochromic element, which includes: A first conductive layer, an electrochromic layer, an electrolyte layer, an ion storage layer, and a second conductive layer arranged in layers in sequence; the first conductive layer and the second conductive layer are used to receive external power to form a voltage difference; the electrochromic layer is used to receive electrons in the electrolyte layer to achieve electrochromism; Wherein, the electrolyte layer includes indium tin oxide nanoparticles uniformly arranged.

[0005] For the electrochromic element provided by the embodiment of this application, by arranging indium tin oxide nanoparticles in the electrolyte layer, since the refractive index of indium tin oxide is relatively high, the overall refractive index of the electrolyte layer can be increased, thereby reducing the interlayer reflectivity between the electrolyte layer and the electrochromic layer and the ion storage layer, and further improving the overall transmittance of the electrochromic element.

[0006] In one embodiment, the average particle size of the indium tin oxide nanoparticles is less than 50 nm.

[0007] In one embodiment, the specific surface area of the indium tin oxide nanoparticles is greater than 20 m 2 / g.

[0008] In one embodiment, the concentration of the indium tin oxide nanoparticles in the electrolyte layer is 0 - 50 wt%.

[0009] In one embodiment, the electrolyte layer further includes an electrolyte material, and the refractive index of the electrolyte layer is 0.01 - 0.05 higher than that of the electrolyte material.

[0010] On the other hand, the present application provides a method for preparing an electrolyte layer of an electrochromic element, which includes: Preparing an electrolyte material solution; Dissolving indium tin oxide material in a solvent to prepare an indium tin oxide nanoparticle solution; Mixing the electrolyte material solution with the indium tin oxide nanoparticle solution; Extracting the solvent in the mixed solution to obtain an electrolyte layer slurry; Coating the electrolyte layer slurry to obtain the electrolyte layer.

[0011] The method for preparing an electrolyte layer of an electrochromic element provided by the embodiments of the present application can make the prepared electrolyte layer include indium tin oxide nanoparticles by mixing an indium tin oxide nanoparticle solution in an electrolyte material solution, thereby increasing the refractive index of the electrolyte layer, and further being beneficial to improving the overall light transmittance of the electrochromic element.

[0012] In one embodiment, the solvent is an alcohol or an aqueous solution.

[0013] In one embodiment, the step of dissolving indium tin oxide material in a solvent to prepare an indium tin oxide nanoparticle solution specifically includes: configuring the solvent so that the average particle size of the indium tin oxide nanoparticles is less than 50 nm.

[0014] In one embodiment, the step of mixing the electrolyte material solution with the indium tin oxide nanoparticle solution specifically includes: configuring the ratio of the electrolyte material solution to the indium tin oxide nanoparticle solution so that the concentration of the indium tin oxide nanoparticles in the electrolyte layer slurry is 0 - 50 wt%.

[0015] In one embodiment, the step of mixing the electrolyte material solution with the indium tin oxide nanoparticle solution specifically includes: configuring the ratio of the electrolyte material solution to the indium tin oxide nanoparticle solution so that the specific surface area of the indium tin oxide nanoparticles is greater than 20 m 2 / g. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of an electrochromic element in an embodiment of the present application.

[0017] Figure 2 For Figure 1 Partial enlarged structural diagram.

[0018] Figure 3 It is a flowchart of the method for preparing an electrolyte layer of an electrochromic element in an embodiment of the present application.

[0019] Description of the Main Element Symbols Electrochromic element: 100 The first substrate layer: 10 The first conductive layer: 20 The electrochromic layer: 30 The electrolyte layer: 40 Indium tin oxide nanoparticles: 41 The electrolyte material: 43 The ion storage layer: 50 The second conductive layer: 60 The second substrate layer: 70 The control circuit: 90 Electrons: E Ions: Ion Steps: S1, S2, S3, S4, S5.

[0020] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific embodiments

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0022] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application.

[0023] In order to further elaborate on the technical means and effects adopted by the present application to achieve the predetermined purpose, the following detailed description of the present application is made in conjunction with the drawings and preferred embodiments.

[0024] Please refer to Figure 1 and Figure 2 simultaneously. The electrochromic element 100 provided by the embodiment of the present application includes a first substrate layer 10, a first conductive layer 20, an electrochromic layer 30, an electrolyte layer 40, an ion storage layer 50, a second conductive layer 60, and a second substrate layer 70 which are stacked. Among them, the electrolyte layer 40 includes uniformly distributed indium tin oxide nanoparticles 41.

[0025] The first substrate layer 10 and the second substrate layer 70 are used to support and protect other layer structures. In this embodiment, the materials of the first substrate layer 10 and the second substrate layer 70 are polyethylene terephthalate (PET). The PET material has high mechanical strength and impact resistance, and is resistant to high temperature and oil, with low gas permeability. The high light transmittance of the PET material is beneficial to improving the overall light transmittance of the electrochromic element 100. In other embodiments, the first substrate layer 10 and the second substrate layer 70 may also be other materials, such as polymethyl methacrylate or polycarbonate, and the present application does not limit this.

[0026] The first conductive layer 20 and the second conductive layer 60 are used to be electrically connected to an external control circuit 90, so as to receive externally applied power to form a voltage difference. Specifically, in this embodiment, the first conductive layer 20 is electrically connected to the positive electrode of the control circuit 90, and the second conductive layer 60 is electrically connected to the negative electrode of the control circuit 90. When the control circuit 90 applies power to the first conductive layer 20 and the second conductive layer 60, an electric field is generated between the first conductive layer 20 and the second conductive layer 60 due to the voltage difference. The electrons E between the first conductive layer 20 and the second conductive layer 60 migrate towards the first conductive layer 20, and the ions Ion migrate towards the second conductive layer 60. That is, the electrons E between the first conductive layer 20 and the second conductive layer 60 accumulate on the electrochromic layer 30, and the ions Ion migrate into the ion storage layer 50. The electrochromic layer 30 receives the electrons E, thereby undergoing an oxidation reaction, causing the electrochromic layer 30 to change to a colored state and be able to absorb light in a specific wavelength band, thus showing color.

[0027] The first conductive layer 20 and the second conductive layer 60 are transparent conductive materials. In this embodiment, the first conductive layer 20 and the second conductive layer 60 are indium tin oxide. In other embodiments, the first conductive layer 20 and the second conductive layer 60 may also be other transparent conductive materials, and the present application does not limit this.

[0028] The electrochromic layer 30 is used to absorb electrons E under the power applied by the control circuit 90, thereby undergoing an oxidation reaction to change to a colored state. The electrochromic layer 30 in the colored state can absorb light in a specific wavelength band, thus showing color. By adjusting the intensity of the voltage applied by the control circuit 90, the electrochromic layer 30 can receive different numbers of electrons E. The more electrons E the electrochromic layer 30 receives, the more parts are converted into the colored state, so the more light is absorbed, making the color shown by the electrochromic layer 30 darker; the fewer electrons E the electrochromic layer 30 receives, the fewer parts are converted into the colored state, and the lighter the color shown.

[0029] In this embodiment, the material of the electrochromic layer 30 is an inorganic electrochromic material. For example, the material of the electrochromic layer 30 is tungsten trioxide WO3 , WO 3 is dark blue in the colored state, and the light transmittance can be reduced to less than 20%. And WO 3 has high cycle stability and can be used repeatedly for many times. The electrochromic layer 30 can also be other materials, such as nickel oxide, etc., and the present application does not limit this.

[0030] The electrolyte layer 40 further includes an electrolyte material 43. Indium tin oxide nanoparticles 41 are uniformly mixed in the electrolyte material 43 to be used for improving the refractive index of the electrolyte layer 40. Specifically, the electrolyte material 43 can be carbonate, polyethylene oxide (PEO) or polyvinylidene fluoride, etc. The electrolyte material 43 has high transparency and good water solubility. The refractive index of the electrolyte material 43 is usually 1.3 - 1.4, while the refractive index of the electrochromic layer 30 is about 2, and the refractive index of the ion storage layer 50 is about 2.2. Therefore, when only the electrolyte material 43 is used as the electrolyte layer 40, the difference in the refractive index between the electrolyte layer 40 and the electrochromic layer 30 as well as the ion storage layer 50 is relatively large. When light passes through media with different refractive indices, reflection usually occurs at the position where there is a difference in the refractive index between layers. The larger the difference in the refractive index between layers, the larger the interlayer reflectivity, resulting in a decrease in the overall light transmittance. And the refractive index of indium tin oxide material is about 1.8. When the indium tin oxide nanoparticles 41 are mixed with the electrolyte material 43, the overall refractive index of the electrolyte layer 40 can be increased, thereby reducing the difference in the refractive index between the electrolyte layer 40 and the electrochromic layer 30 as well as the ion storage layer 50, and further reducing the interlayer reflectivity and improving the overall light transmittance of the electrochromic element 100.

[0031] In this embodiment, the refractive index of the electrolyte layer 40 is 0.01 - 0.05 higher than the refractive index of the electrolyte material 43, and specifically can be 0.01, 0.02, 0.03, 0.04 or 0.05 higher. In other embodiments, the refractive index of the electrolyte layer 40 can also be controlled by controlling the concentration of the indium tin oxide nanoparticles 41, and the present application does not limit this.

[0032] In this embodiment, the average particle size of the indium tin oxide nanoparticles 41 is less than 50 nm. The average particle size of the indium tin oxide nanoparticles 41 can specifically be values such as 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, etc. Specifically, by controlling the average particle size of the indium tin oxide nanoparticles 41 to be less than the wavelength of visible light, the Rayleigh scattering effect of light can be reduced, thereby avoiding the turbidity or haze caused by the presence of large particle size indium tin oxide nanoparticles 41, which is beneficial to maintaining a high light transmittance. Controlling the average particle size is also beneficial to making the indium tin oxide nanoparticles 41 mix more uniformly with the electrolyte material 43, thereby effectively adjusting the refractive index of the entire electrolyte layer 40.

[0033] In this embodiment, the specific surface area of the indium tin oxide nanoparticles 41 is greater than 20 m 2 / g. The specific surface area of the indium tin oxide nanoparticles 41 can specifically be 25 m 2 / g, 30 m 2 / g, 35 m 2 / g, 40 m 2 / g, 45 m 2 / g, 50 m 2 / g, etc. Specifically, by controlling the specific surface area of the indium tin oxide nanoparticles 41, the indium tin oxide nanoparticles 41 can have more surface active sites, thereby enhancing the interfacial binding force with the electrolyte material 43, reducing the light scattering caused by aggregation, being beneficial to promoting the uniform dispersion of the indium tin oxide nanoparticles 41, and ensuring the light transmittance of the electrolyte layer 40. And a high specific surface area is also beneficial to shortening the transmission paths of ions Ion and electrons E, thereby reducing the response time of electrochromism and being beneficial to improving the speed of electrochromism.

[0034] In this embodiment, the concentration of the indium tin oxide nanoparticles 41 in the electrolyte layer 40 is 0 - 50 wt%. The concentration of the indium tin oxide nanoparticles 41 in the electrolyte layer 40 can specifically be values such as 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, etc. Specifically, by controlling the concentration of the indium tin oxide nanoparticles 41, it is beneficial to regulate the refractive index of the electrolyte layer 40, and it is beneficial to avoiding the turbidity or haze caused by the concentration of the indium tin oxide nanoparticles 41 being too high and exceeding the light scattering critical threshold, which is beneficial to keeping the electrolyte layer 40 with a high light transmittance.

[0035] The ion storage layer 50 is used to receive ions Ion migrating from the electrolyte layer 40 under the electric power applied by the control circuit 90, so as to balance the charge and maintain the stability of the electrochromic layer 30 in the colored state. In this embodiment, the material of the ion storage layer 50 is nickel oxide NiO. NiO has a high ion storage capacity, relatively high chemical stability and relatively high ion conduction ability. And NiO also has weak light absorption to reduce the interference with the main color tone of the electrochromic layer 30. In other embodiments, the material of the ion storage layer 50 can also be tungsten trioxide, titanium dioxide, etc., and the present application does not limit this.

[0036] In the electrochromic element 100 provided by the embodiment of the present application, by setting the electrolyte layer 40 to include an electrolyte material 43 and indium tin oxide nanoparticles 41 uniformly mixed in the electrolyte material 43, while increasing the refractive index of the electrolyte layer 40 to reduce the interlayer reflectance and improving the overall light transmittance of the electrochromic element 100, the switching electrical efficiency of the electrochromic element 100 can also be improved. Specifically, since the indium tin oxide nanoparticles 41 are conductive materials, the ions Ion in the electrolyte layer 40 are more likely to migrate, so that the voltage required to control the electrochromic layer 30 to change color is reduced. By setting the specific surface area of the indium tin oxide nanoparticles 41, the transmission paths of the ions Ion and electrons E can be shortened, thereby reducing the response time of electrochromism and being beneficial to improving the speed of electrochromism.

[0037] The embodiment of the present application also provides a method for preparing an electrolyte layer of an electrochromic element, which is used to prepare the electrolyte layer 40 in the above embodiment. Please refer to Figure 3 , the method for preparing an electrolyte layer of an electrochromic element includes: Step S1: Prepare an electrolyte material solution; Step S2: Dissolve indium tin oxide material in a solvent to prepare an indium tin oxide nanoparticle solution; Step S3: Mix the electrolyte material solution and the indium tin oxide nanoparticle solution; Step S4: Extract the solvent in the mixed solution to obtain an electrolyte layer slurry; Step S5: Coat the electrolyte layer slurry to obtain the electrolyte layer.

[0038] In step S2, the solvent can specifically be alcohols or aqueous solutions. The solvent is used to dissolve the indium tin oxide material, so as to decompose the indium tin oxide material into indium tin oxide nanoparticles 41.

[0039] Step S2 specifically includes: configuring a solvent such that the average particle size of indium tin oxide nanoparticles 41 is less than 50 nm. Specifically, the particle size of indium tin oxide nanoparticles 41 can be controlled by adding a surface-active material, such as ethanolamine, to the solvent. By controlling the content of the surface-active material, the average particle size of indium tin oxide nanoparticles 41 can be changed.

[0040] Step S2 also includes: configuring a solvent such that the specific surface area of indium tin oxide nanoparticles 41 is greater than 20 m 2 / g. Specifically, the specific surface area of indium tin oxide nanoparticles 41 can be controlled during the formation of indium tin oxide nanoparticles 41. For example, the pH value or temperature of the solvent can be adjusted to adjust the specific surface area, or the indium tin oxide nanoparticle solution can be ultrasonically treated. This application does not limit this, as long as the specific surface area of indium tin oxide nanoparticles 41 can be adjusted to be greater than 20 m 2 / g, it is within the scope of this application.

[0041] Step S3 specifically includes: configuring the ratio of the electrolyte material solution to the indium tin oxide nanoparticle solution such that the concentration of indium tin oxide nanoparticles 41 in the electrolyte layer slurry is 0 - 50 wt%. Specifically, the concentration of indium tin oxide can be recorded in step S2, so as to determine the concentration of indium tin oxide nanoparticles 41 when the electrolyte material solution and the indium tin oxide nanoparticle solution are mixed.

[0042] Step S4 can include: separating indium tin oxide nanoparticles 41 and the electrolyte material 43 from the solvent through a solvothermal reaction. Step S4 can also include: adjusting the temperature and time of the solvothermal reaction to control the specific surface area of indium tin oxide nanoparticles 41.

[0043] Step S5 specifically is: disposing the electrolyte layer slurry on the electrochromic layer 30 or the ion storage layer 50 to obtain the electrolyte layer 40. Step S5 can also be: coating the electrolyte layer slurry on a substrate to obtain the electrolyte layer 40, and peeling the electrolyte layer 40 from the substrate. That is, the electrolyte layer 40 can be formed independently or directly formed on the electrochromic layer 30 or the ion storage layer 50. This application does not limit this.

[0044] The method for preparing the electrolyte layer of the electrochromic element provided by the embodiment of the present application can obtain indium tin oxide nanoparticles 41 by dissolving indium tin oxide materials in a solvent. By mixing the indium tin oxide nanoparticle solution with the electrolyte material solution, the refractive index of the finally obtained electrolyte layer 40 can be increased, so that the electrochromic element 100 including the electrolyte layer 40 has higher light transmittance. In addition, the electrolyte layer 40 can also improve the switching electrical efficiency of the electrochromic element 100. Specifically, since the indium tin oxide nanoparticles 41 are conductive materials, the ions Ion in the electrolyte layer 40 are more likely to migrate, reducing the voltage required to control the color change of the electrochromic layer 30. By setting the specific surface area of the indium tin oxide nanoparticles 41, the transmission paths of the ions Ion and electrons E can be shortened, thereby reducing the response time of electrochromism and facilitating the improvement of the electrochromic speed.

[0045] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate the present application and are not intended to limit the present application. As long as within the scope of the substantial spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope claimed by the present application.

Claims

1. An electrochromic element, characterized in that: include: A first conductive layer, an electrochromic layer, an electrolyte layer, an ion storage layer and a second conductive layer are sequentially stacked; The first conductive layer and the second conductive layer are used to receive external power to form a voltage difference; the electrochromic layer is used to receive electrons in the electrolyte layer to achieve electrochromism; Wherein, the electrolyte layer includes uniformly arranged indium tin oxide nanoparticles.

2. The electrochromic element according to claim 1, characterized in that: The average particle size of the indium tin oxide nanoparticles is less than 50 nm.

3. The electrochromic element according to claim 1, characterized in that: The specific surface area of ​​the indium tin oxide nanoparticles is greater than 20 m 2 / g.

4. The electrochromic element according to claim 1, characterized in that: The concentration of the indium tin oxide nanoparticles in the electrolyte layer is 0-50 wt %.

5. The electrochromic element according to claim 1, characterized in that: The electrolyte layer further comprises an electrolyte material, and the refractive index of the electrolyte layer is 0.01-0.05 higher than the refractive index of the electrolyte material.

6. A method for preparing an electrolyte layer of an electrochromic element, used for preparing the electrolyte layer of the electrochromic element according to any one of claims 1 to 5, characterized in that: include: preparing an electrolyte material solution; dissolving an indium tin oxide material in a solvent to prepare an indium tin oxide nanoparticle solution; mixing the electrolyte material solution with the indium tin oxide nanoparticle solution; extracting the solvent in the mixed solution to obtain an electrolyte layer slurry; The electrolyte layer slurry is applied to obtain the electrolyte layer.

7. The method for preparing an electrochromic element electrolyte layer according to claim 6, characterized in that: The solvent is alcohol or aqueous solution.

8. The method for preparing an electrochromic element electrolyte layer according to claim 6, characterized in that: The step of dissolving the indium tin oxide material in a solvent to prepare an indium tin oxide nanoparticle solution specifically includes: configuring the solvent so that the average particle size of the indium tin oxide nanoparticles is less than 50 nm.

9. The method for preparing an electrochromic element electrolyte layer according to claim 6, characterized in that: The step of mixing the electrolyte material solution with the indium tin oxide nanoparticle solution specifically includes: configuring the ratio of the electrolyte material solution to the indium tin oxide nanoparticle solution so that the concentration of the indium tin oxide nanoparticles in the electrolyte layer slurry is 0-50wt%.

10. The method for preparing an electrochromic element electrolyte layer according to claim 6, characterized in that: The step of dissolving the indium tin oxide material in a solvent to prepare an indium tin oxide nanoparticle solution specifically includes: configuring the ratio of the electrolyte material solution to the indium tin oxide nanoparticle solution so that the specific surface area of ​​the indium tin oxide nanoparticles is greater than 20 m 2 / g.

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