Highly transparent and colorless electrochromic counter electrode and preparation method thereof

Abstract

The present application discloses a highly transparent and colorless electrochromic counter electrode and a preparation method thereof. The electrochromic counter electrode comprises a substrate layer; a transparent adhesive layer, which is arranged on one side of the substrate layer. The transparent adhesive layer is provided with a plurality of grooves interconnected in a grid shape on the side facing away from the substrate layer. The electrode material and the ion storage material are sequentially arranged in the grooves in the direction away from the substrate layer. The present application provides a grid-shaped groove structure on the transparent adhesive layer, and arranges the electrode material and the ion storage material in the groove structure. While ensuring the ability of the counter electrode to balance the working electrode, the ion storage material is prevented from affecting the transmittance and transparency of the counter electrode. Compared with the ion storage material arranged on the front, the transmittance of the counter electrode can be significantly improved, and the color change of the ion storage material when the voltage changes can be avoided from affecting the electrochromic device. At the same time, since the color of the ion storage material itself has less influence on the electrochromic device, the selection range of the ion storage material can also be greatly expanded.

Description

Technical Field

[0001] The present application belongs to the field of electrochromic technology, and specifically relates to a highly transparent and colorless electrochromic counter electrode and a preparation method thereof. Background Art

[0002] Electrochromism refers to the phenomenon in which the optical properties of electroactive materials, including transmittance, reflectivity, and color, undergo reversible changes under varying voltages. These changes occur across infrared, ultraviolet, visible, and most other electromagnetic wavelengths. Therefore, electrochromism holds great promise for applications in building energy conservation and automotive smart windows.

[0003] Common electrochromic devices are primarily composed of two electrodes, an electrolyte, an electrochromic layer (working electrode), and an ion storage layer (counter electrode). Because electrochromism is essentially a redox reaction, an ion storage layer is required to balance the charge generated by the working electrode during the redox process while also storing the corresponding counterions. If the ion storage layer matches the electrochromic layer, the stability of the device can be greatly improved, the operating voltage can be reduced, and the color change speed of the device can be increased.

[0004] Common counter electrode materials currently include ferrocene, benzoquinone / hydroquinone, MCCP, PEDOT:PSS, and titanium dioxide. The ion storage layer is usually made of an electrochromic material with a polarity opposite to that of the electrochromic material. For example, PProDOT is used as the anodic working electrode, and the counter electrode can be made of a cathodic electrochromic material such as titanium dioxide or tungsten oxide. Existing counter electrodes have the following drawbacks:

[0005] 1. For electrochromic smart windows, the counter electrode needs to have colorless and high transmittance. However, the widely used PEDOT:PSS and ferrocene, which have excellent performance, are blue and yellow respectively, and cannot be used in areas where high transparency is required in the faded state, limiting the application scenarios during the electrochromic period.

[0006] 2. In order to ensure that the counter electrode can balance the working electrode, the thickness of the ion storage layer material needs to be increased, but the increase in thickness will lead to a decrease in the transmittance of the counter electrode;

[0007] 3. The ion storage layer material will also change color when the voltage is switched, affecting the application in scenes where colorlessness is required;

[0008] 4. The current method of using ion storage layer materials makes the color of the electrode darker during the color change process of the electrochromic device, which will affect its transmittance. Summary of the Invention

[0009] The purpose of this application is to provide a highly transparent and colorless electrochromic counter electrode and its preparation method, so as to solve the technical problems in the prior art of low transparency and transmittance of the counter electrode, color change when voltage is switched, ion storage layer materials, and the ion storage layer affecting the transmittance when the electrochromic device changes color.

[0010] To achieve the above purpose, a technical solution adopted in this application is:

[0011] Provided is a highly transparent, colorless electrochromic counter electrode, comprising:

[0012] substrate layer;

[0013] A transparent adhesive layer is arranged on one side of the substrate layer. The side of the transparent adhesive layer facing away from the substrate layer is provided with a plurality of grid-like grooves interconnected with each other. Electrode materials and ion storage materials are sequentially arranged in the grooves in a direction away from the substrate layer.

[0014] In one or more embodiments, the ion storage material includes one or a combination of multiple materials selected from the group consisting of MXene, PEDOT:PSS, tungsten oxide, nickel oxide, titanium dioxide, and cesium oxide.

[0015] In one or more embodiments, the ion storage material includes a combination of multiple materials selected from MXene, PEDOT:PSS, tungsten oxide, nickel oxide, titanium dioxide, and cesium oxide, and the multiple materials are mixed and evenly arranged in the groove, or are stacked in sequence in the groove.

[0016] In one or more embodiments, the depth of the groove is 1 to 10 micrometers, and the width of the groove is 1 to 10 micrometers.

[0017] In one or more embodiments, the plurality of grooves are evenly arranged on the entire surface of the transparent adhesive layer, and the plurality of grooves are interconnected to form a regular hexagonal grid, a square grid, or a triangular grid.

[0018] In one or more embodiments, the substrate layer is made of PET, glass or PEN.

[0019] In one or more embodiments, the thickness of the electrode material layer is 0.1 to 2.5 micrometers.

[0020] In one or more embodiments, the light transmittance of the electrochromic counter electrode at 350-800 nm is greater than 60%.

[0021] To achieve the above purpose, another technical solution adopted by this application is:

[0022] Provided is a method for preparing a highly transparent, colorless electrochromic counter electrode according to any of the above embodiments, comprising:

[0023] A transparent adhesive layer is prepared on one side of the substrate layer by nanoimprinting, so that a plurality of grooves interconnected in a grid pattern are provided on the side of the transparent adhesive layer facing away from the substrate layer;

[0024] Filling the electrode material into the groove and drying;

[0025] The ion storage material is filled into the groove and dried to obtain the electrochromic counter electrode.

[0026] In one or more embodiments, the drying temperature of the electrode material is 25-120°C, and the drying temperature of the ion storage material is 25-120°C.

[0027] Different from the prior art, the present invention has the following advantages:

[0028] By providing a grid-like groove structure on the transparent adhesive layer and arranging the electrode material and ion storage material within the groove structure, the present application can ensure the counter electrode's ability to balance the working electrode while preventing the ion storage material from affecting the counter electrode's light transmittance and transparency. Compared with ion storage materials arranged on the front, the light transmittance of the counter electrode can be significantly improved, and the color change of the ion storage material when the voltage changes can prevent the electrochromic device from being affected. At the same time, because the color of the ion storage material itself has less impact on the electrochromic device, the range of ion storage materials can be greatly expanded.

[0029] The transmittance of the electrochromic counter electrode of the present application is less affected by voltage. At -0.2 to 0.8 V, the transmittance for light with a wavelength of 300 to 800 nm is greater than 60%, and the transmittance for light with a wavelength of 450 to 800 nm is greater than 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic top view of the structure of an embodiment of a highly transparent and colorless electrochromic counter electrode of the present application;

[0031] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of AA;

[0032] Figure 3 This is a schematic flow chart of an embodiment of a method for preparing a highly transparent and colorless electrochromic counter electrode of the present application;

[0033] Figure 4 Schematic diagram of the top view of the electrochromic counter electrode of Example 1 of the present application;

[0034] Figure 52 is a schematic diagram of a top view of the electrochromic counter electrode of Example 2 of the present application;

[0035] Figure 6 2 is a schematic top view of the electrochromic counter electrode of Example 3 of the present application;

[0036] Figure 7 is the transmittance of the electrochromic counter electrode of Example 1 of the present application for light of different wavelengths at different voltages;

[0037] Figure 8 It is the transmittance of the electrochromic counter electrode of the comparative example of the present application for light of different wavelengths at different voltages. DETAILED DESCRIPTION

[0038] The present application will be described in detail below with reference to the various embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application, and any structural, methodological, or functional modifications made by a person skilled in the art based on these embodiments are included within the scope of protection of the present application.

[0039] As mentioned in the background technology, the current ion storage layer method has a great impact on the transmittance and transparency of the electrochromic device due to the dark color of the ion storage material, and cannot be used in fields that require higher transparency in the faded state; and when the electrochromic device changes color, the ion storage material will also change color as the voltage changes, affecting the application in scenes that require colorlessness.

[0040] In addition, in order to ensure that the counter electrode can balance the working electrode, the thickness of the ion storage layer material needs to be increased. However, after the thickness of the ion storage layer arranged on the front side is increased, the transmittance of the counter electrode will decrease.

[0041] In order to solve the above problems, the applicant has developed a highly transparent and colorless electrochromic counter electrode, which has high light transmittance and transparency, and has little effect on the color during electrochromism when the voltage changes. When applied to an electrochromic device, it can make the electrochromic device have a higher transmittance in the faded state, and can be used in glasses, smart windows and other fields.

[0042] Specifically, see Figure 1 and Figure 2 , Figure 1 This is a schematic top view of the structure of an embodiment of a highly transparent and colorless electrochromic counter electrode of the present application. Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of AA.

[0043] like Figure 1 and Figure 2 As shown, the electrochromic counter electrode includes a substrate layer 10 and a transparent adhesive layer 20 .

[0044] The substrate layer 10 can be made of transparent materials such as PET, glass or PEN.

[0045] The transparent adhesive layer 20 is arranged on one side of the substrate layer, and a plurality of grid-like grooves 201 are provided on a side of the transparent adhesive layer facing away from the substrate layer.

[0046] like Figure 1 As shown, in this embodiment, a plurality of grooves 201 are connected in sequence to form a regular hexagonal grid structure.

[0047] like Figure 2 As shown, the electrode material 202 and the ion storage material 203 are sequentially arranged in the groove 201 along a direction away from the substrate layer.

[0048] In one embodiment, the depth of the groove 201 may be 1 to 10 micrometers, and the width of the groove 201 may be 1 to 10 micrometers.

[0049] In one embodiment, the electrode material 202 may be a conductive metal material such as silver or gold, and the thickness of the electrode material 202 may be 0.1 to 2.5 microns.

[0050] In one embodiment, the ion storage material 203 may include one of MXene, PEDOT:PSS, tungsten oxide, nickel oxide, titanium dioxide, and cesium oxide.

[0051] In one embodiment, the ion storage material 203 may include a combination of multiple materials selected from MXene, PEDOT:PSS, tungsten oxide, nickel oxide, titanium dioxide, and cesium oxide. The multiple materials may be mixed and evenly arranged in the groove, or may be stacked in sequence in the groove, both of which can achieve the effects of this embodiment.

[0052] In one embodiment, the ion storage material 203 may fill the groove 201 so that the surface of the ion storage material 201 is flush with the surface of the transparent adhesive layer 20 , thereby maximizing the ion storage capacity.

[0053] By providing a grid-shaped groove 201 structure on the transparent adhesive layer 20 and arranging the electrode material 202 and the ion storage material 203 in the groove 201 structure, it is possible to ensure the ability of the counter electrode to balance the working electrode while preventing the ion storage material 203 from affecting the transmittance and transparency of the counter electrode. Compared with the ion storage material arranged on the front, the transmittance of the counter electrode can be significantly improved, and the discoloration of the ion storage material when the voltage changes can be avoided from affecting the electrochromic device. At the same time, since the color of the ion storage material itself has less influence on the electrochromic device, the selection range of ion storage materials can also be greatly expanded.

[0054] In the above embodiment, several grooves 201 are arranged in a regular hexagonal grid structure; it can be understood that in other embodiments, several grooves 201 can also be interconnected and arranged in a grid structure of any other shape, such as a square grid structure, a triangular grid structure and other irregular grid structures, all of which can achieve the effect of this embodiment.

[0055] In order to maximize the amount of ion storage material disposed, a plurality of grooves 201 may be evenly disposed on the entire surface of the transparent adhesive layer.

[0056] This application also provides a method for preparing the electrochromic counter electrode. Figure 3 , Figure 3 It is a flow chart of one embodiment of a method for preparing a highly transparent and colorless electrochromic counter electrode of the present application.

[0057] The preparation method comprises:

[0058] S100, preparing a transparent adhesive layer on one side of the substrate layer by nanoimprinting, so that a plurality of grid-like grooves are provided on the side of the transparent adhesive layer facing away from the substrate layer.

[0059] First, a transparent adhesive layer can be prepared on one side of the substrate layer by nanoimprinting. When the transparent adhesive layer is formed, a nanoimprinting mold is used to simultaneously contact and form grid-like grooves on the surface of the transparent adhesive layer.

[0060] S200, filling the groove with electrode material and drying.

[0061] Specifically, after the groove is formed, the electrode material can be filled into the groove first.

[0062] In one embodiment, the electrode material may be silver paste, which is scraped into the bottom of the groove by scraping, and then dried. The drying temperature may be 25-120°C.

[0063] After drying is completed, an electrode material layer is formed at the bottom of the groove.

[0064] S300, filling the groove with ion storage material and drying it to obtain an electrochromic counter electrode.

[0065] The ion storage material can then be filled onto the electrode material and dried to obtain an ion storage layer.

[0066] The ion storage material can be scraped into the grooves using a slurry coating method. When the ion storage material is a combination of multiple materials, the different materials can be scraped into the grooves step by step, or the materials can be mixed to obtain a mixed slurry before scraping into the grooves, both of which can achieve the effects of this embodiment.

[0067] The effects of the technical solution of this application are further elaborated in detail below with reference to specific embodiments.

[0068] Example 1: A highly transparent, colorless electrochromic counter electrode is prepared by the following method:

[0069] 1. A transparent adhesive layer was prepared on a PET substrate using nanoimprint technology. A regular hexagonal grid-like groove structure was evenly arranged on the surface of the transparent adhesive layer. The grooves were 3 microns wide and 3 microns deep.

[0070] 2. Apply the silver paste to the inside of the grid-shaped grooves and dry it at 50°C to form a 1-micron electrode silver layer in the grooves;

[0071] 3. PEDOT:PSS slurry and tungsten oxide particles were mixed evenly in a mass ratio of 1:1 to obtain a mixed slurry. The mixed slurry was scraped into the grid-shaped grooves and dried at 50°C to obtain an electrochromic counter electrode.

[0072] See also Figure 4 , Figure 4 This is a schematic diagram of the top view of the electrochromic counter electrode of Example 1 of the present application.

[0073] Example 2:

[0074] A highly transparent and colorless electrochromic counter electrode is prepared by the following method:

[0075] 1. Nanoimprint technology is used to prepare a transparent adhesive layer on a glass substrate. The surface of the transparent adhesive layer is evenly arranged with a square grid-like groove structure. The groove width is 1 micron and the depth is 10 microns.

[0076] 2. Apply the silver paste to the inside of the grid-shaped grooves and dry it at 50°C to form a 2.5-micron electrode silver layer in the grooves;

[0077] 3. Apply PEDOT:PSS slurry by scraping and fill it into the grid-shaped grooves, then apply tungsten oxide particle slurry by scraping and fill it into the grid-shaped grooves, and dry it at 50°C to obtain an electrochromic counter electrode.

[0078] See also Figure 5 , Figure 5 This is a schematic diagram of the top view of the electrochromic counter electrode of Example 2 of the present application.

[0079] Example 3:

[0080] A highly transparent and colorless electrochromic counter electrode is prepared by the following method:

[0081] 1. A transparent adhesive layer was prepared on a PEN substrate using nanoimprint technology. Triangular grid-like groove structures were evenly arranged on the surface of the transparent adhesive layer. The grooves were 10 microns wide and 1 micron deep.

[0082] 2. Apply the silver paste to the inside of the grid-shaped grooves and dry it at 50°C to form a 0.1 micron electrode silver layer in the grooves;

[0083] 3. PEDOT:PSS slurry and tungsten oxide particles (particle size of 500 nm) were mixed evenly in a mass ratio of 1:01 to obtain a mixed slurry. The mixed slurry was scraped into the grid-shaped grooves and dried at 50°C to obtain an electrochromic counter electrode.

[0084] See also Figure 6 , Figure 6 This is a schematic diagram of the top view of the electrochromic counter electrode of Example 3 of the present application.

[0085] Comparative Example:

[0086] An electrochromic counter electrode is prepared by the following method:

[0087] An electrode and a tungsten oxide material layer are prepared on the surface of a PET substrate to obtain an electrochromic counter electrode.

[0088] Effect example:

[0089] The transmittance of the electrochromic counter electrodes of Example 1 and Comparative Example 1 for light of different wavelengths was tested at different voltages, and the results were as follows: Figure 7 and Figure 8 .

[0090] See also Figure 7 , Figure 7 is the transmittance of the electrochromic counter electrode of Example 1 of the present application for light of different wavelengths at different voltages. Figure 7 As shown, the transmittance of the electrochromic counter electrode of Example 1 is less affected by voltage. At -0.2 to 0.8 V, the transmittance for light with a wavelength of 300 to 800 nm is greater than 60%, and the transmittance for light with a wavelength of 450 to 800 nm is greater than 80%.

[0091] See also Figure 8 , Figure 8 is the transmittance of the electrochromic counter electrode of the comparative example of the present application for light of different wavelengths at different voltages. Figure 8 As shown, the transmittance of the electrochromic counter electrode of the comparative example is greatly affected by voltage. When the voltage increases, the transmittance decreases significantly, and the transmittance for light with a wavelength greater than 450 nm is low.

[0092] In summary, the electrochromic counter electrode of the embodiment of the present application can significantly prevent the discoloration of the ion storage material from affecting the electrochromic device when the voltage changes, and can significantly improve the light transmittance of the counter electrode.

[0093] The foregoing description of the present disclosure is provided to enable any person skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is intended to be consistent with the widest range of principles and novel features disclosed herein.

Claims

1. A highly transparent colorless electrochromic counter electrode, characterized in that: include: substrate layer; A transparent adhesive layer is arranged on one side of the substrate layer, and a side of the transparent adhesive layer facing away from the substrate layer is provided with a plurality of grid-like grooves interconnected with each other, wherein the electrode material and the ion storage material are sequentially arranged in the grooves in a direction away from the substrate layer; The ion storage material includes one or a combination of MXene, PEDOT:PSS, tungsten oxide, nickel oxide, titanium dioxide, and cesium oxide.

2. The electrochromic counter electrode according to claim 1, characterized in that The ion storage material includes a combination of multiple materials selected from MXene, PEDOT:PSS, tungsten oxide, nickel oxide, titanium dioxide, and cesium oxide. The multiple materials are mixed and evenly arranged in the groove, or are stacked in sequence in the groove.

3. The electrochromic counter electrode according to claim 1, characterized in that: The depth of the groove is 1 to 10 microns, and the width of the groove is 1 to 10 microns.

4. The electrochromic counter electrode according to claim 1, characterized in that: The plurality of grooves are evenly arranged on the entire surface of the transparent adhesive layer, and the plurality of grooves are interconnected to form a regular hexagonal grid, a square grid or a triangular grid.

5. The electrochromic counter electrode according to claim 1, characterized in that: The material of the substrate layer is PET, glass or PEN.

6. The electrochromic counter electrode according to claim 1, characterized in that: The thickness of the electrode material is 0.1 to 2.5 microns.

7. The electrochromic counter electrode according to any one of claims 1 to 6, characterized in that: The light transmittance of the electrochromic counter electrode at 350-800 nm is greater than 60%.

8. A method for preparing the highly transparent colorless electrochromic counter electrode according to any one of claims 1 to 7, characterized in that: include: A transparent adhesive layer is prepared on one side of the substrate layer by nanoimprinting, so that a plurality of grooves interconnected in a grid pattern are provided on the side of the transparent adhesive layer facing away from the substrate layer; Filling the electrode material into the groove and drying; The ion storage material is filled into the groove and dried to obtain the electrochromic counter electrode.

9. The preparation method according to claim 8, characterized in that The drying temperature of the electrode material is 25-120°C, and the drying temperature of the ion storage material is 25-120°C.

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