CN220873421U

CN220873421U - Flexible electrochromic capacitor

Info

Publication number: CN220873421U
Application number: CN202322504111.3U
Authority: CN
Inventors: 杨枢; 刘艳花; 赵世晴; 李桐; 陈林森
Original assignee: Suzhou University; SVG Tech Group Co Ltd
Current assignee: Suzhou University; SVG Tech Group Co Ltd
Priority date: 2023-09-14
Filing date: 2023-09-14
Publication date: 2024-04-30
Anticipated expiration: 2033-09-14

Abstract

The utility model provides a flexible electrochromic capacitor which comprises a conductive layer, a color-changing layer, an electrolyte layer and a galvanized electrode layer which are sequentially stacked, wherein the galvanized electrode layer is in a grid structure. In the flexible electrochromic capacitor, the galvanized electrode layer serving as the anode is gridded, so that the thickness of the electrochromic capacitor is reduced, important parameters such as square resistance, transparency and mechanical property can be regulated and controlled by changing the period, line width and grid shape of the grid-shaped structure, and the zinc loading capacity of the galvanized electrode layer can be controlled, thereby overcoming the serious dendrite problem generated by adopting zinc foil as an electrode in the conventional electrochromic device and prolonging the service life of the device.

Description

Flexible electrochromic capacitor

Technical Field

The utility model relates to the technical field of electrochromic devices, in particular to a flexible electrochromic capacitor.

Background

Electrochromic is a phenomenon that optical properties (reflectivity, transmittance, absorptivity and the like) of a material change in color stably and reversibly under the action of an applied electric field, and is expressed as a reversible change in color and transparency in appearance. Materials having electrochromic properties are referred to as electrochromic materials, and devices made from electrochromic materials are referred to as electrochromic devices.

Electrochromic devices are devices in which the color of the device changes reversibly by alternating voltages, i.e., coloring and fading, of the device. The application fields of the anti-dazzle device mainly include intelligent windows, display technologies, military camouflage, flexible wearable equipment, anti-dazzle rearview mirrors and the like. The advent of electronic skin products in the field of smart wear and medical detection requires the development of ultra-thin, attachable and high performance smart flexible batteries. In this case, electrochromic capacitor (battery) dual function devices are of great interest. The device has the energy storage function of a super capacitor (battery) and the electrochromic function of regulating optical characteristics according to voltage, so that the device becomes a popular choice of intelligent power supply equipment, and particularly in the electrochromic super capacitor (battery) adopting a zinc anode, the device has the characteristics of strong reducibility, rapid self-discharge and high stability and high capacity in an aqueous electrolyte, so that the device is more interesting. However, current zinc anode electrochromic supercapacitors (batteries) generally employ metal foils (zinc foils) of various shapes as electrodes, which results in three main problems: firstly, the zinc foil releases a large amount of zinc ions, which causes serious dendrite fixation problem and shortens the service life of the device; secondly, the electric field generated by the zinc foil is often uneven, so that the color changing effect is affected; finally, zinc foil is relatively thick, increasing the thickness and weight of the device, and is not well suited for flexible and wearable applications.

Disclosure of utility model

The utility model aims to provide a flexible electrochromic capacitor and a preparation method thereof, which are used for solving the problems that the service life of a device is short, the color-changing effect is poor, the thickness and the weight of the device are increased, and the flexible electrochromic capacitor is not suitable for flexible and wearable applications.

The technical scheme for realizing the aim of the utility model is as follows: the utility model provides a flexible electrochromic capacitor which comprises a conductive layer, a color-changing layer, an electrolyte layer and a galvanized electrode layer which are sequentially stacked, wherein the galvanized electrode layer is in a grid structure.

In one embodiment of the present utility model, the conductive layer is a metal grid electrode; the zinc plating electrode layer is formed by depositing zinc on the surface of the grid electrode, and the metal grid electrode is made of silver, copper and nickel.

In an embodiment of the present utility model, a grid aspect ratio of the metal grid electrode is less than 2:1; the mesh period of the metal mesh electrode is 50-200 mu m.

In one embodiment of the present utility model, the electrolyte layer is an electrolyte layer containing zinc ions, including hydrogels containing zinc ions; the electrolyte layer is flexible and stretchable; the electrolyte layer has a light transmittance of greater than 80%; the electrolyte layer has a thickness of 100 μm to 200 μm.

In an embodiment of the present utility model, the color-changing layer single-layer structure includes PEDOT: PSS.

In an embodiment of the present utility model, the color-changing layer is a double-layer or multi-layer structure, including a PEDOT: PSS; the material of one side far away from the conductive layer is tungsten trioxide or Prussian blue.

Compared with the prior art, the utility model has the beneficial effects that: in the flexible electrochromic capacitor, the galvanized electrode layer serving as the anode is gridded, so that the thickness of the electrochromic capacitor is reduced, important parameters such as square resistance, transparency and mechanical property can be regulated and controlled by changing the period, line width and grid shape of the grid-shaped structure, and the zinc loading capacity of the galvanized electrode layer can be controlled, thereby overcoming the serious dendrite problem generated by adopting zinc foil as an electrode in the conventional electrochromic device and prolonging the service life of the device.

Drawings

Fig. 1 is a schematic structural view of a flexible electrochromic device according to an embodiment of the present utility model.

Detailed Description

The following describes in further detail the embodiments of the present utility model with reference to the drawings and examples. The following examples are illustrative of the utility model and are not intended to limit the scope of the utility model.

The utility model provides a flexible electrochromic device, as shown in fig. 1, a flexible electrochromic capacitor of an embodiment comprises a conductive layer 11, a color-changing layer 12, an electrolyte layer 13 and a galvanized electrode layer 14 which are sequentially stacked, wherein the galvanized electrode layer 14 is in a grid structure.

In the flexible electrochromic capacitor, the galvanized electrode layer 14 is arranged on the conductive layer 11, the galvanized electrode layer 14 is in a grid structure, the thickness of the electrochromic capacitor is reduced, important parameters such as sheet resistance, transparency and mechanical property can be regulated and controlled by changing the period, line width and grid shape of the grid structure, and the zinc loading capacity of the galvanized electrode layer 14 can be controlled, so that the serious dendrite problem caused by adopting zinc foil as an electrode in the conventional electrochromic device is solved, and the service life of the device is prolonged.

In this embodiment, the zinc-plated electrode layer 14 is a metal mesh electrode surface deposited zinc, which is used to provide support to the zinc-plated electrode layer 14. The metal mesh electrode is usually made of silver, copper, nickel or other metal with high conductivity, and the material specifically selected in this embodiment is nickel.

The zinc-plated electrode layer 14 has the same metal mesh electrode as the conductive layer 11, i.e., the conductive layer 11 is a nickel metal mesh electrode layer, and the zinc-plated electrode layer 11 is a zinc-plated metal mesh.

In this embodiment, the aspect ratio of the metal mesh electrode is less than 2:1. The aspect ratio of the metal grid electrode can be set by those skilled in the art according to practical situations, and is not limited only herein.

In this embodiment, the galvanized electrode layer 14 includes a plurality of first grid cells that are any one or a combination of a plurality of circles, ellipses, regular octagons, regular hexagons, or cucurbits.

In this embodiment, the conductive layer 11 is also in a grid structure, i.e. the conductive layer 11 is a metal grid electrode. The conductive layer 11 includes a plurality of second mesh units, which are any one or a combination of a plurality of circles, ellipses, regular octagons, regular hexagons, or calabashes.

The use of the grid-like conductive layer 11 and the galvanized electrode layer 14 ensures a more uniform electric field distribution of the electrochromic capacitor. This is because the grid structure can distribute the electric field more uniformly across the flexible electrochromic capacitor surface, reducing the difference in electric field gradients, thereby enhancing the stability and reliability of the device. The optical performance of the electrochromic capacitor can be optimized by adjusting the grid line width and the thickness, and the line width and the thickness of the interval can be selected to reduce reflection and scattering and improve the transmissivity, so that the visual effect and the usability of the device are enhanced. Meanwhile, by adjusting the line width and the thickness in the interval of the line width and the thickness, the required electric field distribution can be realized, thereby optimizing the electrochromic effect and the energy consumption.

In this embodiment, the electrolyte layer 13 may be an electrolyte layer containing zinc ions, including hydrogels containing zinc ions; the electrolyte layer 13 has flexibility and stretchability, and has a light transmittance of more than 80%. The thickness of the electrolyte layer 13 is 100 μm to 200 μm. The thickness of the electrolyte layer may be set to 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, etc. by those skilled in the art according to actual circumstances, and is not limited only herein.

In another preferred embodiment, the grid-like structure of the galvanized electrode layer 14 is a periodically distributed structure with a period ranging from 50 μm to 200 μm. Correspondingly, the grid-like structure of the conductive layer 11 is a periodically distributed structure with a period ranging from 50 μm to 200 μm. The period of the galvanized electrode layer 14 can be set to 50μm、60μm、70μm、80μm、90μm、100μm、110μm、120μm、130μm、140μm、150μm、160μm、170μm、180μm、190μm、192μm、194μm、198μm、200μm according to actual requirements by those skilled in the art, and the like, and is not limited only herein; the period of the conductive layer 11 may be 50μm、60μm、70μm、80μm、90μm、100μm、110μm、120μm、130μm、140μm、150μm、160μm、166μm、170μm、180μm、184μm、190μm、198μm、200μm or the like according to actual requirements, and is not limited herein.

In this embodiment, the material in the conductive layer 11 is iron, copper, nickel, zinc, silver, gold, or the like. In this embodiment, nickel metal is selected.

In this embodiment, the color-changing layer 12 includes an electrochromic material selected from any one or more of an organic electrochromic material, an inorganic electrochromic material, or a composite electrochromic material. The electrochromic material comprises a metal oxide, preferably tungsten trioxide or nickel oxide. The organic electrochromic material is preferably any one or more of viologen, isophthalate, metal phthalocyanine, pyridine metal complex, polyaniline, polypyrrole and polythiophene. The electrochromic material selected in this example was a mixed solution of polyethylene dioxythiophene (PEDOT) and polyphenylene acetate sulfonate (PSS). PEDOT: the PSS has better conductive performance and capacitance performance, is a color-changing material, and is an ideal choice of a color-changing layer of an electrochromic device.

The electrolyte layer 13 may be an inorganic gel layer or an organic gel layer, and the inorganic gel layer includes an electrolyte such as acrylamide, sodium chloride, lithium chloride, sodium perchlorate, lithium perchlorate, etc., and tetramethyl ethylenediamine, ammonium persulfate, methylene bisacrylamide. The organic gel layer comprises organic polymer such as acrylonitrile-styrene, curing agent such as 1-methylimidazole and 4-methylimidazole, electrolyte such as sodium chloride, lithium chloride, sodium perchlorate and lithium perchlorate, and organic solvent such as acetonitrile, tetrahydrofuran and toluene.

In this embodiment, the electrolyte layer 13 is an organic gel layer, wherein the main material is hydrogel. Hydrogels are gel systems composed of water molecules and high molecular weight polymers, which are usually organic compounds such as polyacrylamide or polyacrylic acid. Hydrogels have very high water absorption and can absorb a large amount of water, thereby providing good ion transport channels. This facilitates the transport and movement of ions in the electrolyte, promoting the electrochromic effect of the device. Meanwhile, the hydrogel can undergo gel-sol transition under the action of moisture. When an electric field is applied, moisture in the electrolyte layer may be absorbed, forming a gel state, thereby changing the color of the device. When the electric field disappears, the water can be released, so that the gel is converted into a sol state, and the original color of the device is restored.

The utility model also provides a manufacturing method of the flexible electrochromic capacitor, which is used for manufacturing the flexible electrochromic capacitor, and comprises the following steps:

S1, forming a conductive layer 11 with a grid structure on a substrate, and stripping the conductive layer 11 from the substrate;

S2, providing two substrates, and injecting electrolyte solution between the two substrates to manufacture and form an electrolyte layer 13;

s3, manufacturing and forming a color-changing layer 12 on the substrate, attaching an electrolyte layer 13 to the color-changing layer 12, and stripping the color-changing layer 12 from the substrate to obtain a composite layer containing the color-changing layer 12 and the electrolyte layer 13;

s4, preparing zinc ion complex solution for electrodeposition to form a galvanized electrode layer 14;

S5, packaging the conductive layer 11, the composite layer (the color-changing layer 12 and the electrolyte layer 13) and the galvanized electrode layer 14 to prepare and form the flexible electrochromic capacitor.

In another preferred embodiment, in step S2, the electrolyte layer may further include immersing the electrolyte layer in a zinc-containing solution to supplement zinc ions, and the zinc ions permeate to obtain a zinc-containing ion electrolyte layer.

In step S3, fabricating the color-changing layer 12 on the substrate includes spin-coating a color-changing material on the substrate, and then drying at a high temperature, thereby obtaining the color-changing layer 12.

In another preferred embodiment, in step S3, forming the color-changing layer 12 on the substrate includes spin-coating a color-changing material on the substrate, followed by high temperature drying, spin-coating another color-changing material or electrochemical deposition of another chemistry, followed by high temperature drying.

It should be noted that, the substrate used in step 1 is a conductive substrate, such as ITO glass; the substrate used in the step 2 is a glass substrate; the two substrates in step 3 are identical, and the substrates are glass substrates.

The specific preparation process of the conductive layer 11 is as follows:

1. Photoresist is coated on a conductive substrate (such as ITO glass), and the thickness of the photoresist is controlled by combining the dilution degree of the photoresist in a spin coating or doctor blade coating mode. The glue thickness is typically in the order of 0.5 μm to 10 μm.

Specifically, the thickness of the photoresist may be set to 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.5 μm, 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 8.5 μm, 9.0 μm, 10.0 μm according to actual conditions by those skilled in the art.

2. The photoresist may then be in a grid-like trench structure using laser direct writing techniques. And the etching method can also be adopted to carry out net etching, and the mask plate is used for exposing and developing the photoresist to obtain a corresponding net structure.

3. And (3) placing the developed ITO glass into an electroforming pool for electroforming, and depositing metal materials (such as silver, copper, nickel and the like) in the exposed micro-grooves. The metal material deposition thickness can be observed by confocal microscopy. According to different deposition time, metal grids with different thickness can be obtained, but the height of deposited metal cannot exceed the height of the groove, otherwise, the transmittance of the metal grids is directly affected.

The conductive layer 11 is formed on the conductive substrate without supporting the substrate material, so that free bending can be realized, meanwhile, the structure of the flexible electrochromic capacitor is simplified, the thickness of the flexible electrochromic capacitor is far lower than that of the conventional electrochromic device, the conductivity and the overall transmittance of the flexible electrochromic capacitor are improved, and the manufacturing cost is reduced.

In the color-changing layer 12, PEDOT because the device requires both capacitive and electrochromic properties: PSS is used for better conductivity and capacitance property, is a color-changing material, and is an ideal choice of a color-changing layer of an electrochromic device. PEDOT may also be: PSS is considered as part of the conductive electrode at PEDOT: and other color-changing materials (such as tungsten trioxide and Prussian blue) are overlapped under the PSS film to obtain better color-changing effect. The preparation process is as follows:

1. Placing the glass substrate into a plasma cleaner for cleaning for 5-10 minutes, and increasing the hydrophilicity of the surface of the glass substrate.

2. The filtered PEDOT: the PSS solution was spin-coated onto a glass substrate (3000 rpm, 30 s) and subsequently baked at 100℃for 5-10 minutes to give PEDOT: PSS film. This procedure can be repeated 3 times to give a PEDOT thickness of around 250 nm: PSS film.

3. Paste hydrogel on glass substrate PEDOT: the PSS film side was heated at 100deg.C for 5min, after which the hydrogel was removed and PEDOT was taken in the tape: the PSS film is peeled off. Obtaining hydrogel and PEDOT: the thickness of the device is greatly reduced due to the integral structure of the PSS film.

Around the fabrication of the wearable device, the electrolyte layer 13 is first to be ultra-thin, flexible and stretchable. Hydrogels not only meet the above requirements, but also have high transmittance and strong ion transport properties, and become the primary choice for the electrolyte layer 13. The preparation method comprises the following steps:

1. 10ml of deionized water was first taken, and 4g of acrylamide monomer, 0.02g of ammonium persulfate, and 0.04 g of N, N' -methylenebisacrylamide were added to the solution to dissolve and stirred at room temperature for 2 hours.

2. The hydrogel solution was dropped between two glass substrates, and a hydrogel film (100 μm-200 μm) to a controlled thickness was formed by capillary phenomenon, followed by heating at 100℃for 5 minutes to obtain a solid hydrogel.

3. And immersing the hydrogel into a zinc sulfate solution with the concentration of 2mol/L to supplement zinc ions, and obtaining the zinc ion hydrogel after the zinc ions permeate. The hydrogel containing zinc ions can form a battery structure with a zinc anode.

After deposition of metallic zinc, the zinc anode acts as a counter electrode, promoting self-coloration by the difference in redox potential gradient between the zinc anode and the electrochromic cathode. The self-coloring process does not require an external power source and has a self-power supply function.

The low level of metal nucleation sites on the substrate may be induced by too low an operating current, thereby limiting the growth of subsequent crystals. And too high an operating current will deposit excessive metal nucleation sites on the substrate, resulting in a larger bulk metal morphology. The precise initial operating current may control different levels of nucleation growth and the second stage current may change the driving force for subsequent levels of crystal growth. So that a proper metal zinc loading can be found through the regulation and control of the stage current and the concentration of the deposition solution. The preparation process is as follows:

1. Preparing zinc ion complex solution (such as zinc acetate and zinc sulfate solution), wherein the larger concentration can lead to the formation of metallic zinc on the surface of nickel grid into blocks, and the concentration is usually 2mol/L.

2. The three-electrode method is adopted for electrodeposition, a metallic nickel grid is clamped to an electrode clamp to be used as a working electrode, a counter electrode is a platinum sheet or a platinum wire electrode, and a reference electrode is a saturated calomel electrode.

3. The deposition of metallic zinc is performed by a phase current mode of the electrochemical workstation. The nano morphology of the surface zinc is regulated and controlled by the metal zinc through stepped deposition voltage, so that metal electrodes with different zinc loadings can be obtained. Meanwhile, the surface zinc layer has a good layered nano structure, the electrochemical active area is greatly increased, and the charge-discharge performance is good.

The flexible electrochromic capacitor of this embodiment has a nickel mesh electrode (conductive layer 11), PEDOT: a four-layer ultrathin structure composed of PSS film (color-changing layer 12), hydrogel (electrolyte layer 13) and grid zinc electrode (zinc-plated electrode layer 14). The overall thickness of the integral flexible electrochromic capacitor is not more than 250 mu m, and the requirements of ultrathin and attachable wearable devices are met. The specific principle is that the working voltage drives zinc ions to be inserted into the working electrode from the zinc anode, so that the color change layer 12 is correspondingly switched in color, and the zinc ions are inserted into the zinc anode from the working electrode in the discharging process. The color change and energy storage functions are achieved by the penetration of zinc ions in the color change layer 12. Meanwhile, because zinc has strong reducibility and forms a larger potential difference with the working electrode, the flexible high-electrochromic capacitor can be rapidly self-discharged (self-colored) under the condition of no external circuit, so that the flexible high-electrochromic capacitor has excellent rapid corresponding time and high reversibility.

In this document, unless specifically stated and limited otherwise, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly coupled, detachably coupled, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms described above will be understood to those of ordinary skill in the art in a specific context.

In this document, the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "vertical", "horizontal", etc. refer to the directions or positional relationships based on those shown in the drawings, and are merely for clarity and convenience of description of the expression technical solution, and thus should not be construed as limiting the present utility model.

In this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a list of elements is included, and may include other elements not expressly listed.

The foregoing is merely illustrative of the present utility model, and the present utility model is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims

1. The flexible electrochromic capacitor is characterized by comprising a conductive layer, a color-changing layer, an electrolyte layer and a galvanized electrode layer which are sequentially stacked, wherein the galvanized electrode layer is in a grid-shaped structure.

2. The flexible electrochromic capacitor according to claim 1, wherein the conductive layer is a metal mesh electrode; the zinc plating electrode layer is formed by depositing zinc on the surface of the grid electrode, and the metal grid electrode is made of silver, copper and nickel.

3. The flexible electrochromic capacitor according to claim 2, wherein the metal grid electrode has a grid aspect ratio of less than 2:1; the mesh period of the metal mesh electrode is 50-200 mu m.

4. The flexible electrochromic capacitor according to claim 1, wherein the electrolyte layer is a zinc ion-containing electrolyte layer comprising a zinc ion-containing hydrogel; the electrolyte layer is flexible and stretchable; the electrolyte layer has a light transmittance of greater than 80%; the electrolyte layer has a thickness of 100 μm to 200 μm.

5. The flexible electrochromic capacitor according to claim 1, characterized in that said color-changing layer single-layer structure comprises PEDOT: PSS.

6. The flexible electrochromic capacitor according to claim 1, characterized in that the color-changing layer is a double-layer or multi-layer structure comprising PEDOT on the side close to the conductive layer: PSS; the material of one side far away from the conductive layer is tungsten trioxide or Prussian blue.