Gel electrolyte, preparation method thereof and electrochromic device

Abstract

The invention relates to a gel electrolyte, a preparation method thereof and an electrochromic device. The gel electrolyte comprises an electrolyte salt, a polymer matrix and a solvent, the polymer matrix comprises polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1: (4-8). A specific type of solvent and a specific type of polymer matrix interact with the electrolyte salt, and the ratio of the electrolyte salt to acetamide is controlled, so that a stable eutectic phase and a gel network structure can be formed, a channel is provided for ion transmission, and the ionic conductivity of the gel electrolyte is effectively improved; and when the gel electrolyte with the gel network structure is used for the electrochromic device, relatively high optical contrast and relatively high response speed can be obtained, and the electrochromic device can be rapidly discolored under low voltage.

Description

Technical Field

[0001] The present application relates to the technical field of display devices, and in particular to a gel electrolyte and a preparation method thereof, and an electrochromic device. Background Art

[0002] Electrochromism refers to the fact that under the action of an external electric field, the transmittance of a material changes with the insertion and deinsertion of ions, causing changes in the material structure and valence state, and the corresponding changes in transmittance occur, which is manifested as a change in color in appearance. Electrochromic devices (ECDs) are the main application form of electrochromic technology, including two conductive substrate layers, an electrolyte layer, an electrochromic layer, and an ion storage layer. Due to the characteristics of low power consumption, high optical modulation, flexibility, transparency, and color memory effect of electrochromic devices, they are suitable for a variety of applications such as smart windows, electronic billboards, and portable displays, and have received widespread attention at home and abroad. In addition, since the color change signal displayed by ECD does not come from its luminescence, but from the color change of the EC material itself during the electrochemically driven redox reaction, this not only effectively avoids the damage to the human eye caused by strong blue light, but also enables EC displays to maintain high readability and recognizability under strong ambient light. However, in the blue tinted state, the glass color rendering index (CRl), a quantitative measure of the color appearance of an object illuminated by a non-natural light source compared to the color illuminated by an ideal or natural light source, can reach unacceptable values ​​of less than 10 (compared to values ​​of over 90 for gray or neutral tinted colors); and discomfort reactions to glazing are more frequent in blue tinted glazing than neutral glazing, so the pursuit of high-performance neutral color electrochromic devices is of great importance. However, conventional electrochromic devices have low contrast between the tinted state and the bleached state.

[0003] Therefore, it is necessary to improve the traditional technology. Summary of the invention

[0004] Based on this, the present application provides a gel electrolyte with good optical contrast, a preparation method thereof, and an electrochromic device.

[0005] The technical solution of this application to solve the above technical problems is as follows.

[0006] On one hand, the present application provides a gel electrolyte, comprising an electrolyte salt, a polymer matrix and a solvent, wherein the polymer matrix comprises polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1:(4-8).

[0007] In some embodiments, in the gel electrolyte, the molar ratio of the electrolyte salt to the solvent is 1:(4-6).

[0008] In some embodiments, in the gel electrolyte, the electrolyte salt includes a lithium salt.

[0009] In some embodiments, in the gel electrolyte, the lithium salt includes at least one of lithium perchlorate, lithium hexafluorophosphate, lithium bis(oxalate borate), lithium methanesulfonate, lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate.

[0010] In some embodiments, in the gel electrolyte, the mass of the polymer matrix accounts for 20% to 40% of the total mass of the gel electrolyte.

[0011] On the one hand, the present application provides a method for preparing a gel electrolyte, comprising the following steps:

[0012] An electrolyte salt, a polymer matrix and a solvent are mixed to prepare a gel electrolyte; wherein the polymer matrix includes polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1:(4-8).

[0013] On one hand, the present application provides an electrochromic device, comprising the above-mentioned gel electrolyte or the gel electrolyte prepared by the above-mentioned method for preparing the electrochromic device.

[0014] In some embodiments, the electrochromic device includes a first substrate, a first transparent conductive layer, an anode electrochromic layer, an electrolyte layer, a cathode electrochromic layer, a second transparent conductive layer and a second substrate stacked in sequence, and the electrolyte layer includes the gel electrolyte.

[0015] In some embodiments, in the electrochromic device, the anode electrochromic layer includes a nickel oxide film layer or a nickel oxide film layer doped with a first metal ion, wherein the first metal ion includes Li + 、Al 3+ 、Na + , K + and Co 2+ At least one of; and / or

[0016] The thickness of the anode electrochromic layer is 500 nm to 1000 nm; and / or

[0017] The cathode electrochromic layer includes a tungsten oxide film layer or a tungsten oxide film layer doped with a second metal ion, wherein the second metal ion includes Li + 、Ti 2+ 、Ag + and Mo 6+ At least one of; and / or

[0018] The thickness of the cathode electrochromic layer is 200 nm to 1000 nm; and / or

[0019] The first substrate and the second substrate are independently selected from at least one of soda-lime glass, polymethyl methacrylate, poly(p-terephthalylidene) alcohol, polystyrene, polycarbonate, styrene acrylonitrile, polypropylene, polyimide and polyvinyl chloride; and / or

[0020] The first transparent conductive layer and the second transparent conductive layer independently include at least one of indium tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, metal nanowires, metal grid electrodes, carbon nanotubes and graphene.

[0021] Compared with the prior art, the gel electrolyte of the present application has the following beneficial effects:

[0022] The gel electrolyte of the present application interacts a specific type of solvent and a specific type of polymer matrix with the electrolyte salt, and controls the ratio of the electrolyte salt to acetamide, so as to form a stable eutectic phase and a gel network structure, provide a channel for the transmission of ions, and effectively improve the ionic conductivity of the gel electrolyte; and when the gel electrolyte with the gel network structure is used in an electrochromic device, a higher optical contrast and a faster response speed can be obtained, and the electrochromic device can be made to change color quickly at a low voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0024] Figure 1 is an X-ray diffraction curve diagram of the nickel oxide film prepared in Example 1;

[0025] Figure 2 This is a SEM image of the nickel oxide film prepared in Example 1;

[0026] Figure 3 This is a SEM image of the tungsten oxide film prepared in Example 1;

[0027] Figure 4 This is a time-current curve diagram of the electrochromic device prepared in Example 1;

[0028] Figure 5 is a transmittance curve diagram of the electrochromic device prepared in Example 1;

[0029] Figure 6 is a transmittance curve diagram of the electrochromic device prepared in Example 2;

[0030] Figure 7 is a transmittance curve diagram of the electrochromic device prepared in Example 3;

[0031] Figure 8 The transmittance curve of the electrochromic device prepared in Comparative Example 1;

[0032] Fig. 9 The transmittance curve of the electrochromic device prepared in Comparative Example 2;

[0033] Fig.10 This is a transmittance curve of the electrochromic device prepared in Comparative Example 3. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below in conjunction with the accompanying drawings, implementation modes and examples. It should be understood that these implementation modes and examples are only used to illustrate the present application and are not used to limit the scope of the present application. The purpose of providing these implementation modes and examples is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0035] It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the present application, and the equivalent forms obtained also fall within the scope of protection of the present application. For example, the features illustrated or described as part of one embodiment can be combined in another embodiment in a suitable manner to produce a new embodiment. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing implementation modes and embodiments and are not intended to limit this application.

[0037] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0038] In the present application, "plurality", "multiple", "multiple times", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0039] As used herein, "combination thereof", "any combination thereof", "any combination thereof" etc. include all suitable combinations of any two or more of the listed items.

[0040] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0041] Herein, "preferred", "better", "more preferred", and "suitable" are only used to describe implementation methods or examples with better effects, and it should be understood that they do not constitute a limitation on the scope of protection of this application. If multiple "preferred" items appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "preferred" item is independent.

[0042] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0043] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0044] In the present application, the terms "first", "second", "third", "fourth", etc. in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0045] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0046] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0047] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0048] In this application, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0049] In this application, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 3~5 h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0050] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the invention purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0051] The mass or weight of the relevant components mentioned in the specification of the embodiments of the present application may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the specification of the embodiments of the present application, it is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass or weight described in the specification of the embodiments of the present application may be units known in the chemical industry such as μg, mg, g, and kg.

[0052] An embodiment of the present application provides a gel electrolyte, comprising an electrolyte salt, a polymer matrix and a solvent, wherein the polymer matrix comprises polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1:(4-8).

[0053] By allowing a specific type of solvent and a specific type of polymer matrix to interact with the electrolyte salt and controlling the ratio of the electrolyte salt to acetamide, a stable eutectic phase and a gel network structure can be formed, providing a channel for the transmission of ions and effectively improving the ionic conductivity of the gel electrolyte; and when the gel electrolyte with the gel network structure is used in an electrochromic device, a higher optical contrast and a faster response speed can be obtained, enabling the electrochromic device to change color quickly at a low voltage.

[0054] It can be understood that a specific type of solvent and a specific type of polymer matrix can form a gel network structure with the electrolyte salt, and the electrolyte salt and acetamide are fixed in the three-dimensional network structure, so that the stability of the gel electrolyte is better.

[0055] It can be understood that the molar ratio of electrolyte salt to solvent includes but is not limited to 1:4, 1:4.2, 1:4.5, 1:4.8, 1:5, 1:5.2, 1:5.5, 1:5.8, 1:6, 1:6.2, 1:6.5, 1:6.8, 1:7, 1:7.2, 1:7.5, 1:7.8, 1:8; in some examples, it can be within the range formed by any two of these point values ​​as end values, the same below.

[0056] In some of these examples, the molar ratio of electrolyte salt to solvent in the gel electrolyte is 1:(4~6).

[0057] In some of these examples, the molar ratio of electrolyte salt to solvent in the gel electrolyte is 1:(4~5).

[0058] Optionally, the molar ratio of the electrolyte salt to the solvent is 1:5.

[0059] By controlling the molar ratio of electrolyte salt to solvent, acetamide and electrolyte salt can be further promoted to form a stable eutectic phase, thereby further effectively improving the ionic conductivity and optical contrast of the gel electrolyte.

[0060] It is understood that the electrolyte salt includes but is not limited to at least one of a lithium salt and a sodium salt.

[0061] In some of these examples, in the gel electrolyte, the electrolyte salt includes a lithium salt.

[0062] In some of the examples, in the gel electrolyte, the lithium salt includes at least one of lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium bis(oxalate borate), lithium methanesulfonate, lithium bis(fluorosulfonyl)imide, and lithium tetrafluoroborate (LiBF4).

[0063] Optionally, the lithium salt comprises lithium perchlorate.

[0064] In some of these examples, the mass of the polymer matrix in the gel electrolyte accounts for 20%~40% of the total mass of the gel electrolyte.

[0065] It is understood that the percentage of the mass of the polymer matrix to the total mass of the gel electrolyte includes but is not limited to 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, and 40%.

[0066] In some of these examples, the mass of the polymer matrix in the gel electrolyte accounts for 25%~35% of the total mass of the gel electrolyte.

[0067] It can be understood that in some of the examples, the gel electrolyte includes an electrolyte salt, an organic solvent and a polymer matrix, and the organic solvent includes acetamide. Further, the organic solvent is acetamide.

[0068] In some of these examples, the gel electrolyte consists of an electrolyte salt, an acetamide, and a polymer matrix.

[0069] The gel electrolyte provided in the present application has high transparency, high conductivity, rapid responsiveness, good stability and excellent stability performance, and is easy to assemble, avoiding the problems of leakage, degumming, etc. that are prone to occur in traditional devices using liquid electrolytes, as well as the high cost and toxicity of using ionic solutions.

[0070] An embodiment of the present application provides a method for preparing a gel electrolyte, comprising the following steps:

[0071] The electrolyte salt, polymer matrix and solvent are mixed to prepare a gel electrolyte; wherein the polymer matrix includes polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1:(4-8).

[0072] In some of the examples, in the method for preparing the gel electrolyte, an electrolyte salt and acetamide are mixed, heated to 70° C. to 100° C., and a polymer matrix is ​​added and mixed to prepare the gel electrolyte.

[0073] It is understood that the heating temperature includes but is not limited to 70°C, 80°C, 90°C, 100°C

[0074] An embodiment of the present application provides an electrochromic device, comprising the gel electrolyte described above or the gel electrolyte prepared by the method for preparing the electrochromic device described above.

[0075] In some examples, the electrochromic device includes a first substrate, a first transparent conductive layer, an anode electrochromic layer, an electrolyte layer, a cathode electrochromic layer, a second transparent conductive layer, and a second substrate stacked in sequence, and the electrolyte layer includes the above-mentioned gel electrolyte.

[0076] In some of the examples, in the electrochromic device, the anode electrochromic layer includes a nickel oxide film layer or a nickel oxide film layer doped with a first metal ion, and the first metal ion includes Li + 、Al 3+ 、Na + , K + and Co 2+ At least one of .

[0077] In some of these examples, in electrochromic devices, the thickness of the anode electrochromic layer is 500 nm~1000 nm.

[0078] It can be understood that the thickness of the anode electrochromic layer includes but is not limited to 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, and 1000 nm.

[0079] In some of the examples, in the electrochromic device, the cathode electrochromic layer includes a tungsten oxide film layer or a tungsten oxide film layer doped with a second metal ion, and the second metal ion includes Li + 、Ti 2+ 、Ag + and Mo 6+ At least one of .

[0080] In some of these examples, in electrochromic devices, the thickness of the cathode electrochromic layer is 200 nm~1000 nm.

[0081] It will be appreciated that the thickness of the cathode electrochromic layer includes, but is not limited to, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, and 1000 nm.

[0082] In some of the examples, in the electrochromic device, the first substrate and the second substrate are independently selected from at least one of soda-lime glass, polymethyl methacrylate (PMMA), poly(terephthalate) (PET), polystyrene (PS), polycarbonate (PC), styrene acrylonitrile (AS), polypropylene (PP), polyimide (PI), and polyvinyl chloride (PVC).

[0083] It can be understood that the first substrate and the second substrate may be the same or different.

[0084] In some of the examples, in the electrochromic device, the first transparent conductive layer and the second transparent conductive layer independently include at least one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), metal nanowires, metal grid electrodes, carbon nanotubes and graphene.

[0085] It can be understood that the first transparent conductive layer and the second transparent conductive layer can be the same or different.

[0086] An embodiment of the present application provides a method for preparing an electrochromic device, comprising the following steps:

[0087] A first substrate, a first transparent conductive layer, an anode electrochromic layer, an electrolyte layer, a cathode electrochromic layer, a second transparent conductive layer and a second substrate are sequentially stacked, and the electrolyte layer includes the above-mentioned gel electrolyte.

[0088] In some of the examples, in the method for preparing the electrochromic device, the preparation method of the cathode electrochromic layer includes but is not limited to magnetron sputtering, hydrothermal method, powder method, spin coating method, spraying method, etc.

[0089] In some examples, in the method for preparing the electrochromic device, a cathode electrochromic layer is prepared by a hydrothermal method; further, the preparation includes the following steps:

[0090] The tungsten oxide precursor solution is placed on the second transparent conductive layer, and is subjected to a heating treatment and a first annealing treatment in sequence to prepare a cathode electrochromic layer.

[0091] In some of the examples, in the step of preparing the cathode electrochromic layer, the tungsten oxide precursor solution includes a tungsten oxide precursor and a solvent. Optionally, the tungsten oxide precursor includes but is not limited to at least one of tungsten chloride, tungsten nitrate, etc.; Optionally, the solvent includes ethanol; Further, the tungsten oxide precursor solution also includes an additive; Optionally, the additive includes a second metal ion; Further, the second metal ion includes Li + 、Ti 2+ 、Ag + and Mo 6+ At least one of .

[0092] In some of the examples, in the preparation step of the cathode electrochromic layer, the heating treatment temperature is 70°C to 90°C, and the time is 3 min to 10 min.

[0093] It can be understood that the temperature of the heating treatment includes but is not limited to 70° C., 80° C., and 90° C., and the time includes but is not limited to 3 min, 5 min, and 10 min.

[0094] In some of the examples, in the step of preparing the cathode electrochromic layer, the temperature of the first annealing treatment is 250° C. to 350° C., and the time is 5 min to 20 min.

[0095] It can be understood that the temperature of the first annealing treatment includes but is not limited to 250° C., 300° C., and 350° C., and the time includes but is not limited to 5 min, 8 min, 10 min, and 20 min.

[0096] In some of the examples, in the step of preparing the cathode electrochromic layer, a tungsten oxide precursor solution is disposed on the second transparent conductive layer by spin coating. Further, the spin coating of the tungsten oxide precursor solution and the annealing treatment are repeated multiple times, including but not limited to once, twice, three times or more.

[0097] The prepared tungsten oxide film has a large specific surface area and a large contact area with the electrolyte in the device, which provides more reactive sites. It also shortens the ion transmission distance and promotes effective electrochemical reactions, thus having a faster switching speed.

[0098] In some other examples, in the step of preparing the cathode electrochromic layer, the cathode electrochromic layer is prepared by magnetron sputtering; further, the steps include:

[0099] The cathode electrochromic layer is prepared by using a direct current magnetron sputtering method with metal tungsten as a target in a nitrogen and oxygen atmosphere.

[0100] Further, the flow ratio of nitrogen to oxygen is 1:(0.1~0.8); further, the nitrogen flow rate is 20 sccm~60 sccm; further, the oxygen flow rate is 6 sccm~16 sccm; further, the sputtering power is 110 W~130 W.

[0101] In some of the examples, in the method for preparing an electrochromic device, the preparation method of the anode electrochromic layer includes but is not limited to a hydrothermal method.

[0102] In some examples, in the method for preparing an electrochromic device, preparing an anode electrochromic layer includes the following steps:

[0103] The first transparent conductive layer is immersed in a nickel oxide precursor solution, and sequentially subjected to a heat preservation treatment and a first annealing treatment to form an anode-cathode electrochromic layer on the surface of the first transparent conductive layer.

[0104] It can be understood that before the step of immersing the first transparent conductive layer in the nickel oxide precursor solution, a step of performing a protective treatment on a surface of the first transparent conductive layer is also included. Further, the protective treatment includes but is not limited to using a protective film (such as an adhesive tape) to cover and protect a surface of the first transparent conductive layer, and the protective film will be removed later.

[0105] In some examples, in the preparation method of the electrochromic device, the nickel oxide precursor solution includes a nickel oxide precursor and a solvent. Optionally, the nickel oxide precursor includes but is not limited to at least one of nickel chloride, nickel nitrate, etc.; Optionally, the solvent includes water; Further, the tungsten oxide precursor solution also includes an amine; Optionally, the amine includes hexamethylenetetramine; Further, the tungsten oxide precursor solution also includes an additive; Optionally, the additive includes a first metal ion; Further, the first metal ion includes Li + 、Al 3+ 、Na + , K + and Co 2+ At least one of .

[0106] In some of the examples, in the preparation step of the anode electrochromic layer, the temperature of the insulation treatment is 90°C~120°C, and the time is 0.5 h~2 h.

[0107] It is understood that the temperature of the heat preservation treatment includes but is not limited to 90°C, 100°C, 105°C, 110°C, and 120°C, and the time includes but is not limited to 0.5 h, 1 h, 1.5 h, and 2 h.

[0108] In some examples, in the step of preparing the anode electrochromic layer, the second annealing treatment is performed under a protective gas. Optionally, the protective gas includes but is not limited to at least one of nitrogen, argon, and the like.

[0109] In some of the examples, in the step of preparing the anode electrochromic layer, the second annealing treatment is performed at a temperature of 250° C. to 400° C. and for a time of 0.5 h to 3 h.

[0110] It can be understood that the temperature of the second annealing treatment includes but is not limited to 250° C., 300° C., 350° C., and 400° C., and the time includes but is not limited to 0.5 h, 1 h, 1.5 h, 2 h, and 3 h.

[0111] The prepared nickel oxide film has a loose and porous structure and a large specific surface area, which increases the contact sites between ions and electrons in the electrolyte and the nickel oxide film, thereby improving the contrast and response speed of the device; the nickel oxide film is directly grown in situ on the first transparent conductive layer, has good adhesion to the first transparent conductive layer, is not easy to fall off during the cycle, and has good cycle stability.

[0112] It can be understood that in some of the examples, in the method for preparing the electrochromic device, a first substrate, a first transparent conductive layer with anode and cathode electrochromic layers formed on the surface, the above-mentioned gel electrolyte or a gel electrolyte prepared from the above-mentioned gel electrolyte are sequentially arranged on the anode electrochromic layer, the cathode electrochromic layer, the second transparent conductive layer and the second substrate for assembly to prepare the above-mentioned electrochromic device.

[0113] The electrochromic device provided in the present application or the prepared electrochromic device has abundant raw materials, excellent performance, simple process, low cost, simple operation, is green and sustainable, and has high transparency and contrast.

[0114] The electrochromic device provided in the present application can achieve the color-changing effect at a relatively low voltage (2~2.5V). When a forward voltage is applied, the nickel oxide film of the anode electrochromic layer and the tungsten oxide film of the cathode electrochromic layer are both in a colored state, and the transmittance is reduced; when a reverse voltage is applied, the nickel oxide film of the anode electrochromic layer and the tungsten oxide film of the cathode electrochromic layer are both in a faded state, and the transmittance is increased, and it has good optical modulation performance.

[0115] The electrochromic device provided in the present application has simple device assembly, is easy to achieve large-scale production, has low energy consumption, is green and sustainable, and has significant economic benefits.

[0116] It can be understood that electrochromic devices include but are not limited to applications in electrochromic smart windows, display screens, car skylights, building curtain walls, electronic paper, anti-glare rearview mirrors, AR glasses, etc.

[0117] The present application is further described in detail below in conjunction with specific implementation methods, but the implementation methods of the present application are not limited thereto.

[0118] Example 1

[0119] A complementary neutral color electrochromic device, comprising, from top to bottom, a first substrate, a first transparent conductive layer, an anode electrochromic layer, an electrolyte layer, a cathode electrochromic layer, a second transparent conductive layer, and a second substrate;

[0120] The first substrate and the second substrate are soda-lime glass; the first transparent conductive layer and the second transparent conductive layer are indium tin oxide (ITO); the anode electrochromic layer is a nickel oxide film; the cathode electrochromic layer is a tungsten oxide film; and the electrolyte layer is a gel electrolyte layer. The preparation steps are as follows:

[0121] S1. Rinse two ITO glasses with deionized water, and ultrasonically clean them in anhydrous ethanol and deionized water for 15 minutes, and then blow dry them with a nitrogen gun for later use;

[0122] S2. Add 1 mmol Ni(NO3)2 and 2 mmol HMT (hexamethylenetetramine) to 70 ml distilled water to prepare a nickel oxide precursor solution, and transfer it to a Teflon-lined stainless steel autoclave liner; immerse a piece of ITO glass cleaned in step S1 in the nickel oxide precursor solution, and evenly coat the top surface with polytetrafluoroethylene tape to prevent solution contamination. Seal the autoclave and keep it at 105°C for 1 hour, then cool it naturally to room temperature, take it out, wash it completely with deionized water, dry it in air, and anneal it in an argon environment at 300°C for 1.5 hours to form a mesoporous nickel oxide nanowall array on the surface of the ITO glass. The X-ray diffraction curve of the prepared nickel oxide film is as shown in Figure 1 As shown in the SEM images Figure 2 As shown;

[0123] S3, weigh 0.4g of tungsten chloride and dissolve it in 3.2g of anhydrous ethanol to prepare a tungsten oxide precursor solution; spin-coat the tungsten oxide precursor solution at a speed of 3000 rpm on a piece of ITO glass cleaned in step S1, heat it at 80℃ for 5 minutes and anneal it at 300℃ for 8 minutes, repeat the spin coating and annealing steps three times, and form a tungsten oxide film on the surface of the ITO glass. The SEM image is as shown in FIG. Figure 3 As shown;

[0124] S4, mixing lithium perchlorate and acetamide in a molar ratio of 1:5, heating and stirring at 80°C to form a uniform transparent liquid, then adding polymethyl methacrylate (the mass of polymethyl methacrylate accounts for 30% of the total mass of the gel electrolyte), stirring and dissolving at 90°C, and then cooling to room temperature to obtain a gel electrolyte;

[0125] S5. Surround the ITO glass with tungsten oxide film in S3 and the ITO glass with nickel oxide film in S2 with 0.5 mm thick tape, pour the gel electrolyte obtained in S4 on the tungsten oxide film prepared in S3 and the nickel oxide film prepared in S2 respectively, lay them flat and let them stand, and then assemble them into a device in the order of the first substrate, the first transparent conductive layer, the anode electrochromic layer, the electrolyte layer, the cathode electrochromic layer, the second transparent conductive layer, and the second substrate from top to bottom, and then package them with UV glue in a dry environment to isolate water and oxygen, and finally obtain a complementary neutral electrochromic device.

[0126] Example 1 The time-current curve of the complementary neutral color electrochromic device is as follows Figure 4 shown.

[0127] Depend on Figure 1 and Figure 2 It can be seen that the nickel oxide film prepared in step S2 has a low crystallinity and a fibrous structure; Figure 3 It can be seen that the tungsten oxide film prepared in step S3 has a mesoporous structure.

[0128] The response time of a device is defined as the time required for the current to change by 90%, Figure 4 Calculations show that the coloring time of the complementary neutral color electrochromic device of Example 1 is only 0.37 s, and the fading time is only 0.13 s, which is much faster than traditional devices of the same type.

[0129] Example 2

[0130] The method is basically the same as Example 1, except that step S3 is as follows:

[0131] S3, using metal tungsten as the target, using DC magnetron sputtering method, with a nitrogen flow rate of 40 sccm, an oxygen flow rate of 10 sccm, and a sputtering power of about 120 W, to sputter a tungsten oxide film (thickness of 250 nm) on the surface of the ITO glass.

[0132] Example 3

[0133] The method is basically the same as Example 1, except that step S2 is to prepare a lithium ion-doped nickel oxide film. Step S2 is specifically as follows:

[0134] S2. Add 1 mmol Ni(NO3)2, Li2NO3 with a molar ratio of lithium atoms to nickel atoms of 10%, and 2 mmol HMT (hexamethylenetetramine) into 70 ml of distilled water to prepare a nickel oxide precursor solution, and transfer it to a Teflon-lined stainless steel autoclave lining; immerse a piece of ITO glass cleaned in step S1 in the nickel oxide precursor solution, and evenly coat the top surface with polytetrafluoroethylene tape to prevent solution contamination. Seal the autoclave and keep it at 105°C for 1 hour, then cool it naturally to room temperature, take it out, rinse it completely with deionized water, dry it in air, and anneal it in an argon environment at 300°C for 1.5 hours to form a lithium ion-doped nickel oxide film on the surface of the ITO glass.

[0135] Example 4

[0136] The method is basically the same as Example 1, except that in step S4, the mass of polymethyl methacrylate accounts for 40% of the total mass of the gel electrolyte.

[0137] Comparative Example 1

[0138] The method is basically the same as Example 1, except that in step S4, the acetamide in Example 1 is replaced by an equal molar amount of propylene carbonate.

[0139] Comparative Example 2

[0140] The method is basically the same as Example 1, except that in step S4, the acetamide in Example 1 is replaced by acetamide and N,N-dimethylformyl in a molar ratio of 1:1, and the molar ratio of the total molar amount of acetamide and N,N-dimethylformyl to lithium perchlorate is 5:1.

[0141] Comparative Example 3

[0142] The method is substantially the same as Example 1, except that in step S4, the molar ratio of lithium perchlorate to acetamide is 1:3.

[0143] Comparative Example 4

[0144] The method is basically the same as Example 1, except that in step S4, the polymethyl methacrylate in Example 1 is replaced by polyvinylidene fluoride of the same mass.

[0145] The electrolyte prepared in Comparative Example 4 forms white crystals at room temperature, and its transparency is significantly reduced. At the same time, the crystals interfere with the normal color change process, making the optical difference between the colored state and the faded state smaller, thereby significantly reducing the optical contrast.

[0146] Optical contrast: The optical transmittance of the electrochromic device in the colored state and the optical transmittance in the faded state (Tb) at 630 nm were measured by combining an electrochromic cycle tester and a UV-visible spectrometer. The difference between the optical transmittance in the faded state and the optical transmittance in the colored state is the optical contrast (△T). The results are shown in Table 1 and Figures 5 to 10 The transmittance curves of the complementary neutral color electrochromic devices prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown as follows: Figures 5 to 10 As shown, 1-faded state, 2-colored state.

[0147] Table 1

[0148]

[0149] It can be seen from Table 1 that, compared with the comparative example, the complementary neutral color electrochromic device prepared in each embodiment has a higher contrast ratio, indicating that the complementary electrochromic device prepared in the present application has good optical modulation performance.

[0150] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0151] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A gel electrolyte, characterized in that: The invention comprises an electrolyte salt, a polymer matrix and a solvent, wherein the polymer matrix comprises polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1:(4-8).

2. The gel electrolyte according to claim 1, characterized in that The molar ratio of the electrolyte salt to the solvent is 1:(4-6).

3. The gel electrolyte according to any one of claims 1 to 2, characterized in that The electrolyte salt includes a lithium salt.

4. The gel electrolyte according to claim 3, characterized in that The lithium salt includes at least one of lithium perchlorate, lithium hexafluorophosphate, lithium bis(oxalate borate), lithium methanesulfonate, lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate.

5. The gel electrolyte according to any one of claims 1 to 2 and 4, characterized in that: The mass of the polymer matrix accounts for 20% to 40% of the total mass of the gel electrolyte.

6. A method for preparing a gel electrolyte, characterized in that: The following steps are involved: An electrolyte salt, a polymer matrix and a solvent are mixed to prepare a gel electrolyte; wherein the polymer matrix includes polymethyl methacrylate, the solvent is acetamide, and the molar ratio of the electrolyte salt to the solvent is 1:(4-8).

7. An electrochromic device, characterized in that: The invention comprises the gel electrolyte as claimed in any one of claims 1 to 5 or the gel electrolyte prepared by the preparation method as claimed in claim 6.

8. The electrochromic device according to claim 7, characterized in that: The invention comprises a first substrate, a first transparent conductive layer, an anode electrochromic layer, an electrolyte layer, a cathode electrochromic layer, a second transparent conductive layer and a second substrate which are sequentially stacked, and the electrolyte layer comprises the gel electrolyte.

9. The electrochromic device according to claim 8, characterized in that: The anode electrochromic layer includes a nickel oxide film layer or a nickel oxide film layer doped with a first metal ion, wherein the first metal ion includes Li + 、Al 3+ 、Na + , K + and Co 2+ At least one of; and / or The thickness of the anode electrochromic layer is 500 nm to 1000 nm; and / or The cathode electrochromic layer includes a tungsten oxide film layer or a tungsten oxide film layer doped with a second metal ion, wherein the second metal ion includes Li + 、Ti 2+ 、Ag + and Mo 6+ At least one of; and / or The thickness of the cathode electrochromic layer is 200 nm to 1000 nm.

10. The electrochromic device according to claim 8 or 9, characterized in that: The first substrate and the second substrate are independently selected from at least one of soda-lime glass, polymethyl methacrylate, poly(p-terephthalylidene) alcohol, polystyrene, polycarbonate, styrene acrylonitrile, polypropylene, polyimide and polyvinyl chloride; and / or The first transparent conductive layer and the second transparent conductive layer independently include at least one of indium tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, metal nanowires, metal grid electrodes, carbon nanotubes and graphene.

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