Passive self-powered electrochromic device and preparation method and application thereof

Abstract

The invention provides a passive self-powered electrochromic device and a preparation method and application thereof, and belongs to the technical field of electrochromism. According to the passive self-powered electrochromic device, the quantum dots of the nanoscale size serve as the inorganic electrochromic layer, when the passive self-powered electrochromic device discharges, discharging is conducted through an external load, ions in the electrolyte layer are embedded into the inorganic electrochromic layer, and materials of the inorganic electrochromic layer are subjected to an oxidation-reduction reaction to achieve coloring; under the condition of temperature difference, ions in the quantum dots are removed through the high temperature of the hot end and enter the ion storage layer through the electrolyte layer to be subjected to reduction reaction to output voltage, so that self power supply is realized; wherein the small size and the large specific surface area of the quantum dots are beneficial to adsorption of more ions, and rapid charge transfer and electron transfer kinetics are provided, so that the prepared passive self-powered electrochromic device can realize thermoelectric conversion storage by using indoor and outdoor temperature difference; and the defect that the electrochromic device can be regulated and controlled only by externally applying voltage is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromic technology, and particularly relates to a self-powered electrochromic device and a preparation method and application thereof. Background Art

[0002] Solar light is mainly composed of ultraviolet light, visible light and near-infrared light. Among them, the energy radiated by solar light is mainly concentrated in the visible light band (about 42%) and the near-infrared band (about 49%), which is the main heat source for the increase of the internal environment temperature of buildings and automobiles. Therefore, the photothermal regulation of visible light and near-infrared light has an important impact on the thermal management, energy consumption of buildings and automobiles, and the comfort inside rooms and vehicles. The electrochromic device can control the optical property change of the electrochromic material through an electric signal, and then realize the management and regulation of photothermal, and is widely used in the fields of buildings and automobiles.

[0003] The current electrochromic devices generally consist of a transparent substrate, a transparent conductive layer, an electrochromic layer, an electrolyte layer and an ion storage layer. The electrochromic layer undergoes an electrochemical oxidation-reduction reaction under the action of an external voltage, gains and loses electrons, and changes the color of the material. However, using an external voltage to regulate the electrochromic material has high energy consumption, especially in the case of frequent adjustment, the energy consumption will increase significantly. Summary of the Invention

[0004] The purpose of the present invention is to provide a self-powered electrochromic device and a preparation method and application thereof. The self-powered electrochromic device provided by the present invention can realize the photothermal regulation of the electrochromic device without an external voltage.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a self-powered electrochromic device, including a first transparent conductive substrate, an inorganic electrochromic layer, an electrolyte layer, an ion storage layer and a common glass substrate which are arranged in sequence;

[0007] The material of the inorganic electrochromic layer includes one or more of tungsten oxide quantum dots, titanium oxide quantum dots, prussian blue quantum dots and vanadium oxide quantum dots.

[0008] Preferably, the first transparent conductive substrate includes a transparent substrate and a conductive layer attached to the surface of the transparent substrate; the conductive layer of the first transparent conductive substrate is in contact with the inorganic electrochromic layer; the common glass substrate is in contact with the ion storage layer.

[0009] Preferably, the conductive layer in the first transparent conductive substrate independently includes one or more of an indium tin oxide conductive layer, a fluorine-doped tin oxide conductive layer and an aluminum-doped zinc oxide conductive layer.

[0010] Preferably, the sheet resistance of the conductive layer of the first transparent conductive substrate is independently 5 to 450 Ω / square.

[0011] Preferably, the thickness of the conductive layer of the first transparent conductive substrate is independently 50 to 1500 nm.

[0012] Preferably, the cations in the electrolyte layer include H + , Li + , Zn 2+ , K + and Al 3+ or one or more of them.

[0013] Preferably, the ion storage layer includes one or more of a metal electrode, a polyaniline electrode, a tungsten oxide electrode, and a Prussian blue electrode.

[0014] Preferably, the thickness of the inorganic electrochromic layer is 100 to 1500 nm; the thickness of the electrolyte layer is 50 to 1000 μm; the thickness of the ion storage layer is 100 to 1000 nm.

[0015] The present invention also provides a method for preparing the self-powered electrochromic device described in the above technical solution, including the following steps:

[0016] Prepare an inorganic electrochromic layer on the surface of the first transparent conductive substrate to obtain a first transparent conductive substrate @ inorganic electrochromic layer;

[0017] Prepare an ion storage layer on the surface of a common glass substrate to obtain a common glass substrate @ ion storage layer;

[0018] Seal the first transparent conductive substrate @ inorganic electrochromic layer and the common glass substrate @ ion storage layer to obtain a hollow sandwich structure, and then inject an electrolyte into the cavity of the hollow sandwich structure to obtain a self-powered electrochromic device.

[0019] The present invention also provides the application of the self-powered electrochromic device described in the above technical solution or the self-powered electrochromic device obtained by the preparation method described in the above technical solution in the fields of electrochromic smart windows, new display technologies, distributed energy storage, or secondary batteries.

[0020] The self - powered electrochromic device provided by the present invention includes a first transparent conductive substrate, an inorganic electrochromic layer, an electrolyte layer, an ion storage layer, and a common glass substrate arranged in sequence; the material of the inorganic electrochromic layer includes one or several of tungsten oxide quantum dots, titanium oxide quantum dots, prussian blue quantum dots, and vanadium oxide quantum dots. In the present invention, quantum dots with nanoscale sizes are used as the inorganic electrochromic layer. When the self - powered electrochromic device discharges, it discharges through an external load, enabling ions in the electrolyte layer to be embedded in the inorganic electrochromic layer, and causing an oxidation - reduction reaction in the material of the inorganic electrochromic layer to achieve coloring; under temperature difference conditions, the high temperature at the hot end causes the ions in the quantum dots to escape, enter the ion storage layer through the electrolyte layer, and undergo a reduction reaction to output voltage, thereby achieving self - power supply; among them, the small size of the quantum dots can significantly shorten the diffusion path of the embedded ions in the solid phase, which is beneficial for ions to insert / extract from the electrode material faster, generating a higher voltage; and the quantum dots have a large specific surface area, increasing the reactive area, which is beneficial for adsorbing more ions, providing fast charge transfer and electron transfer kinetics. Thus, the prepared self - powered electrochromic device can utilize the indoor - outdoor temperature difference to achieve thermoelectric conversion storage, overcoming the disadvantage that electrochromic devices require an externally applied voltage for regulation. It can not only achieve self - power supply but also stably supply power externally for a long time under a certain temperature difference. The results of the examples show that the self - powered electrochromic device provided by the present invention can generate an output voltage of 0.92 V under a temperature difference of 25 K, which is used for its own photothermal regulation and external power supply, indicating that the device of the present invention has excellent thermoelectric conversion storage capabilities. Description of the Drawings

[0021] Figure 1 It is a schematic exploded view of the structure of the self - powered electrochromic device provided by the present invention;

[0022] Figure 2 It is an X - ray diffraction pattern of the tungsten oxide quantum dot electrochromic layer in the first soda - lime glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in Example 1 of the present invention;

[0023] Figure 3 It is a surface morphology diagram of the tungsten oxide quantum dot electrochromic layer in the first soda - lime glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in Example 1 of the present invention;

[0024] Figure 4 It is a transmittance spectrum diagram of the tungsten oxide quantum dot electrochromic layer in the first soda - lime glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in Example 1 of the present invention at 1.5 V, 0.8 V, and 0.2 V respectively;

[0025] Figure 5Response time graph of the tungsten oxide quantum dot electrochromic layer in the first soda-lime glass @ indium tin oxide transparent conductive substrate @ tungsten oxide quantum dot electrochromic layer prepared in Example 1 of the present invention under light with a wavelength of 633 nm;

[0026] Figure 6 Graphs showing the relationship between output voltage and time and the thermoelectric potential of the tungsten oxide quantum dot electrochromic layer in the first soda-lime glass @ indium tin oxide transparent conductive substrate @ tungsten oxide quantum dot electrochromic layer prepared in Example 1 of the present invention at different temperatures;

[0027] Figure 7 Transmittance spectra of the self-powered electrochromic device prepared in Example 1 of the present invention at 1.5 V, 0.8 V, and 0.2 V respectively;

[0028] Figure 8 Response time graph of the self-powered electrochromic device prepared in Example 1 of the present invention under light with a wavelength of 633 nm;

[0029] Figure 9 Digital photos of the self-powered electrochromic device prepared in Example 1 of the present invention in three states of 1.5 V, 0.8 V, and 0.2 V;

[0030] Figure 10 Cyclic life graph of the self-powered electrochromic device prepared in Example 1 of the present invention;

[0031] Figure 11 Graph showing the relationship between output voltage and time of the self-powered electrochromic device prepared in Example 1 of the present invention at a stable temperature difference of 25 K;

[0032] Figure 12 Graph showing the change of output voltage with time of the self-powered electrochromic device prepared in Example 1 of the present invention when a 65 kΩ resistor is externally connected at a stable temperature difference of 25 K, and when the resistor and the 25 K temperature difference are removed in sequence;

[0033] Figure 13 Effect diagram of powering an LED after the self-powered electrochromic device prepared in Example 1 of the present invention is fully charged. Detailed implementation manners

[0034] The present invention provides a self-powered electrochromic device, which includes a first transparent conductive substrate, an inorganic electrochromic layer, an electrolyte layer, an ion storage layer, and a common glass substrate arranged in sequence.

[0035] The self - powered electrochromic device provided by the present invention includes a first transparent conductive substrate. In the present invention, the first transparent conductive substrate preferably includes a transparent substrate and a conductive layer attached to the surface of the transparent substrate. In the present invention, the transparent substrate is preferably soda - lime glass. The present invention improves the conductivity and transparency of the self - powered electrochromic device more fully by defining the material of the transparent substrate.

[0036] In the present invention, the conductive layer preferably includes one or several of indium tin oxide conductive layer, fluorine - doped tin oxide conductive layer or aluminum - doped zinc oxide conductive layer. The present invention ensures that the current is more evenly distributed in the self - powered electrochromic device by defining the type of the conductive layer, thereby more fully promoting the redox reaction of the inorganic electrochromic layer to regulate the color.

[0037] In the present invention, the conductive layer of the first transparent conductive substrate preferably contacts the inorganic electrochromic layer. The present invention more fully transmits the current by defining the connection between the conductive layer of the first transparent conductive substrate and the inorganic electrochromic layer, promotes the redox reaction of the inorganic electrochromic layer, and regulates the color.

[0038] In the present invention, the sheet resistance of the first transparent conductive substrate is preferably 5 - 450 Ω / square. In the embodiments of the present invention, the sheet resistance of the first transparent conductive substrate can be specifically 5 Ω / square, 10 Ω / square, 15 Ω / square, 20 Ω / square, 30 Ω / square, 45 Ω / square, 47 Ω / square, 50 Ω / square, 100 Ω / square, 200 Ω / square, 300 Ω / square, 400 Ω / square or 450 Ω / square. The present invention further improves the conductivity and response speed of the prepared self - powered electrochromic device by defining the sheet resistance of the first transparent conductive substrate.

[0039] In the present invention, the thickness of the conductive layer of the first transparent conductive substrate is preferably 50 - 1500 nm. In the embodiments of the present invention, the thickness of the conductive layer of the first transparent conductive substrate can be specifically 50 nm, 80 nm, 100 nm, 106 nm, 200 nm, 300 nm, 400 nm, 500 nm, 700 nm, 900 nm, 1200 nm or 1500 nm. The present invention ensures that the electrochromic material can change color more evenly when undergoing a redox reaction under the action of an electric field by defining the thickness of the conductive layer of the first transparent conductive substrate.

[0040] The present invention has no special requirements for the area of the first transparent conductive substrate, and those skilled in the art can select a suitable size according to actual needs.

[0041] The self - powered electrochromic device provided by the present invention further includes an inorganic electrochromic layer disposed in contact with the first transparent conductive substrate. In the present invention, the material of the inorganic electrochromic layer preferably includes one or several of tungsten oxide quantum dots, titanium oxide quantum dots, prussian blue quantum dots, and vanadium oxide quantum dots, and more preferably tungsten trioxide quantum dots. By defining the material of the inorganic electrochromic layer, the present invention utilizes its small size to significantly shorten the diffusion path of intercalated ions in the solid phase, which is beneficial for ions to insert / extract from the electrode material more quickly, generating more voltage; and quantum dots have a large specific surface area, which is beneficial for adsorbing more ions, providing fast charge transfer and electron transfer kinetics. Thus, the prepared self - powered electrochromic device can utilize the indoor - outdoor temperature difference to achieve thermoelectric conversion and storage, overcoming the disadvantage that electrochromic devices need an external voltage for regulation. It can not only achieve self - power supply without an external power source, but also stably supply power to the outside for a long time under a certain temperature difference; and it has the ability of local surface plasmon resonance (LSPR) absorption in the near - infrared band, which enables it to achieve independent regulation of visible light and near - infrared light, and at the same time accelerates the diffusion speed of ions, thus significantly improving the response speed of the self - powered electrochromic device.

[0042] In the present invention, the thickness of the inorganic electrochromic layer is preferably 100 - 1500 nm. In the embodiments of the present invention, the thickness of the inorganic electrochromic layer can be specifically 100 nm, 200 nm, 250 nm, 300 nm, 400 nm, 500 nm, 587 nm, 650 nm, 900 nm, 1000 nm, 1300 nm, or 1500 nm. By defining the thickness of the inorganic electrochromic layer, the self - powered electrochromic device can have a larger photothermal modulation range while having a faster response speed.

[0043] The self - powered electrochromic device provided by the present invention further includes an electrolyte layer disposed in contact with the inorganic electrochromic layer. In the present invention, the cations in the electrolyte preferably include H + 、Li + 、Zn 2+ 、K + and Al 3+ one or several of them.

[0044] As an implementation, the cations in the electrolyte layer can be Zn 2+ and Al 3+ . In the present invention, Zn 2+ has a smaller ionic radius and weaker electrostatic interaction, and can be embedded / extracted from the lattice of the inorganic electrochromic layer more quickly, improving the response speed of the self - powered electrochromic device; Al 3+ has a higher charge density, which can improve Zn2+ Slow kinetic process, Zn 2+ and Al 3+ synergistic effect can further improve the electrochromic response speed, cycle stability and thermoelectric conversion performance.

[0045] In the present invention, the types of electrolytes in the electrolyte layer preferably include one or more of liquid electrolytes, polymer gel electrolytes, polymer-ceramic hybrid gel electrolytes, mixed solvent gel electrolytes and polymer-liquid electrolytes. By defining the types of electrolytes, the present invention can store and provide the ions required by the electrochromic material more fully, and more fully realize the reversible color change of the electrochromic material.

[0046] As an embodiment, the type of the electrolyte layer may be a liquid electrolyte. In the embodiment of the present invention, the liquid electrolyte may specifically be zinc perchlorate@aluminum perchlorate@propylene carbonate (Zn(ClO4)2@Al(ClO4)3@PC). By defining the electrolyte as zinc perchlorate@aluminum perchlorate@propylene carbonate, the present invention further stores and supplies the ions required by the electrochromic material, and further improves the speed of realizing the reversible color change of the electrochromic material.

[0047] In the present invention, the thickness of the electrolyte layer is preferably 50-1500 μm. In the embodiment of the present invention, the thickness of the electrolyte layer may specifically be 50 μm, 100 μm, 300 μm, 500 μm, 800 μm, 1000 μm, 1300 μm or 1500 μm. By defining the thickness of the electrolyte layer, the present invention can ensure a faster ion transport speed between the electrochromic layer and the ion storage layer, so that the color change speed is faster.

[0048] The self-powered electrochromic device provided by the present invention further includes an ion storage layer in contact with the electrolyte layer.

[0049] In the present invention, the ion storage layer preferably includes one or more of metal electrodes, polyaniline electrodes, tungsten oxide and Prussian blue electrodes. By defining the types of the ion storage layer, the present invention is beneficial to storing the metal released from the electrochromic layer under temperature difference conditions, receiving and supplying the ions migrating during the color change process of the electrochromic layer, and further fully realizing thermoelectric conversion and dual-band photothermal regulation.

[0050] As an implementation mode, the ion storage layer may be a metal electrode. In an embodiment of the present invention, the metal electrode may be a zinc metal electrode. The present invention defines the ion storage layer as a metal electrode, and utilizes its higher ionic conductivity and electrochemical stability to further improve the metal storage released from the electrochromic layer under temperature difference conditions, and further improve the reception and supply of ions that migrate during the color change process of the electrochromic layer, thereby more fully realizing thermoelectric conversion and dual-band photothermal regulation.

[0051] In the present invention, the thickness of the ion storage layer is preferably 100 to 1000 nm. In an embodiment of the present invention, the thickness of the ion storage layer may be specifically 100 nm, 500 nm, 800 nm or 1000 nm. The present invention reduces the operating voltage of the passive self-powered electrochromic device by limiting the thickness of the ion storage layer to fully meet the charge matching.

[0052] The passive self-powered electrochromic device provided by the present invention further comprises a common glass substrate arranged in contact with the ion storage layer. In the present invention, the common glass substrate is in contact with the ion storage layer.

[0053] The present invention uses nanometer-sized quantum dots as the inorganic electrochromic layer. Under temperature difference conditions, the high temperature at the hot end causes the ions in the quantum dots to escape, and a reduction reaction occurs to obtain metal elements that accumulate in the ion storage layer. The small size of the quantum dots can greatly shorten the diffusion path of the embedded ions in the solid phase, which is conducive to faster insertion / exit of the ions into the electrode material and generation of more voltage. The quantum dots have a large specific surface area, which is conducive to the adsorption of more ions and provides fast charge transmission and electron transfer dynamics, so that the passive self-powered electrochromic device can realize thermoelectric conversion storage using the temperature difference between indoor and outdoor, overcoming the disadvantage that the electrochromic device requires an external voltage to be regulated. It can not only realize passive self-powered power, but also realize long-term stable power supply to the outside under a certain temperature difference.

[0054] The present invention also provides a method for preparing the passive self-powered electrochromic device described in the above scheme, comprising the following steps:

[0055] Prepare an inorganic electrochromic layer on the surface of a first transparent conductive substrate to obtain a first transparent conductive substrate@inorganic electrochromic layer;

[0056] An ion storage layer is prepared on the surface of a common glass substrate to obtain a common glass substrate@ion storage layer;

[0057] Seal the first transparent conductive substrate @ inorganic electrochromic layer and the ordinary glass substrate @ ion storage layer to obtain a hollow sandwich structure, and then inject an electrolyte into the cavity of the hollow sandwich structure to obtain a self-powered electrochromic device. In the present invention, an inorganic electrochromic layer is prepared on the surface of the first transparent conductive substrate to obtain the first transparent conductive substrate @ inorganic electrochromic layer.

[0058] In the present invention, before use, the first transparent conductive substrate is preferably cleaned, dried, and surface-pretreated in sequence. In the present invention, the cleaning is preferably performed in sequence by ultrasonic cleaning with deionized water, ultrasonic cleaning with acetone, ultrasonic cleaning with isopropanol, and ultrasonic cleaning with absolute ethanol. In the present invention, the time for ultrasonic cleaning with deionized water, ultrasonic cleaning with acetone, ultrasonic cleaning with isopropanol, and ultrasonic cleaning with absolute ethanol is independently preferably 10 - 15 min. In the examples of the present invention, the time for ultrasonic cleaning with deionized water, ultrasonic cleaning with acetone, ultrasonic cleaning with isopropanol, and ultrasonic cleaning with absolute ethanol is 10 min, 12 min, 13 min, or 15 min respectively. In the present invention, the drying temperature is preferably 50 - 70 °C. In the present invention, the pretreatment is preferably oxygen plasma treatment or ozone treatment. By the pretreatment, oxygen-containing functional groups are introduced onto the surface of the first transparent conductive substrate, which can improve the wettability of the first transparent conductive substrate, making the spraying effect of the inorganic electrochromic material better and the formed inorganic electrochromic layer more uniform.

[0059] In the present invention, the method for preparing the inorganic electrochromic layer is preferably: coating an inorganic electrochromic material solution on the surface of the first transparent conductive substrate to obtain the first transparent conductive substrate @ inorganic electrochromic layer.

[0060] In the examples of the present invention, the coating can be ultrasonic spraying. In the present invention, the nozzle height of the ultrasonic spraying is preferably 1.5 - 6.0 cm. In the examples of the present invention, the nozzle height of the ultrasonic spraying can be specifically 1.5 cm, 3.0 cm, 5.0 cm, or 6.0 cm. In the present invention, the flow rate of the ultrasonic spraying is preferably 0.10 - 0.2 mL / min. In the examples of the present invention, the flow rate of the ultrasonic spraying can be specifically 0.01 mL / min, 0.05 mL / min, 0.1 mL / min, 0.15 mL / min, or 0.20 mL / min. In the present invention, the number of times of the ultrasonic spraying is preferably 50 - 150 times. In the examples of the present invention, the number of times of the ultrasonic spraying can be specifically 50 times, 85 times, 115 times, 135 times, or 150 times.

[0061] As an implementation manner, when the material of the inorganic electrochromic layer is tungsten oxide quantum dots, the inorganic electrochromic material solution is a tungsten oxide quantum dot solution.

[0062] In the present invention, the preparation method of the tungsten oxide quantum dot solution is preferably as follows:

[0063] Mix a tungsten source, water, and concentrated hydrochloric acid, and then perform a metathesis reaction to obtain tungstic acid;

[0064] Mix the tungstic acid with ethylene glycol and then perform a solvothermal reaction to obtain a tungsten oxide quantum dot solution.

[0065] After coating is completed, the present invention preferably performs vacuum drying on the coated product. In the present invention, the degree of vacuum for the vacuum drying is preferably -0.15 to -0.08 MPa. In the examples of the present invention, the degree of vacuum for the vacuum drying can specifically be -0.15 MPa, -0.01 MPa, -0.02 MPa, -0.05 MPa, or -0.08 MPa. In the present invention, the temperature for the vacuum drying is preferably 50 to 70 °C.

[0066] The present invention prepares an ion storage layer on the surface of a common glass substrate to obtain a common glass substrate @ ion storage layer.

[0067] In the present invention, the common glass substrate is preferably cleaned, dried, sealed, and pretreated in sequence before use. In the present invention, the cleaning, drying, sealing, and pretreatment that the common glass substrate is preferably performed in sequence before use are the same as those that the above-mentioned first transparent conductive substrate is preferably performed in sequence before use, and will not be elaborated here.

[0068] As an implementation manner, when the ion storage layer is a metal electrode, the preparation method is preferably as follows: Dig out a rectangle in the middle of the ion storage layer material to obtain an ion storage layer material frame, and then bond it to the surface of the common glass substrate. In the present invention, the ion storage layer material is preferably polished, ultrasonically cleaned, and dried in sequence before use.

[0069] The present invention has no special limitation on the size of the rectangle, and it is only necessary to inject a standby electrolyte.

[0070] The present invention has no special limitation on the bonding, and any bonding method well-known in the art can be used. In the present invention, the bonding preferably uses double-sided tape.

[0071] After obtaining the first transparent conductive substrate @ inorganic electrochromic layer and the common glass substrate @ ion storage layer, the present invention seals the first transparent conductive substrate @ inorganic electrochromic layer and the common glass substrate @ ion storage layer to obtain a hollow sandwich structure, and then injects an electrolyte into the cavity of the hollow sandwich structure to obtain a self-powered electrochromic device.

[0072] As an implementation manner, the electrolyte may be zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte.

[0073] In the present invention, the preparation method of the zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte is preferably:

[0074] Mix zinc perchlorate, aluminum perchlorate and propylene carbonate solution to obtain zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte.

[0075] In the present invention, the encapsulating material for sealing preferably includes one or several of 3M tape, UV curable adhesive and silicone rubber.

[0076] The present invention also provides the application of the self-powered electrochromic device described in the above solution or the self-powered electrochromic device obtained by the preparation method described in the above solution in the fields of electrochromic smart windows, new display technologies, distributed energy storage or secondary batteries.

[0077] The self-powered electrochromic device of the present invention utilizes the small size of quantum dots to greatly shorten the diffusion path of inserted ions in the solid phase, which is beneficial to the faster insertion / extraction of ions into / from the electrode material, generating more voltage; and the quantum dots have a large specific surface area, which is beneficial to adsorbing more ions, providing fast charge transport and electron transfer kinetics. Therefore, the prepared self-powered electrochromic device can utilize the indoor and outdoor temperature difference to realize thermoelectric conversion storage, overcoming the disadvantage that the electrochromic device needs an external voltage to be regulated. It can not only achieve self-powered power supply, but also can stably supply power externally for a long time under a certain temperature difference, and has good application prospects in the fields of electrochromic smart windows, new display technologies, distributed energy storage or secondary batteries.

[0078] To further illustrate the present invention, the solutions of the present invention will be described in detail below in conjunction with the drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0079] In the present invention, unless otherwise specified, the drugs or reagents used are all commercially available products.

[0080] Example 1

[0081] A self-powered electrochromic device, as Figure 1 shown, is composed of a first transparent conductive substrate, an inorganic electrochromic layer, an electrolyte layer, an ion storage layer and a common glass substrate arranged in sequence;

[0082] Among them, the first transparent conductive substrate is a soda-lime glass@indium tin oxide transparent conductive substrate with a sheet resistance of 50 Ω / square and a conductive layer thickness of 100 nm; the inorganic electrochromic layer is a tungsten trioxide quantum dot electrochromic layer with a thickness of 500 nm; the electrolyte layer is a zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte layer with a thickness of 1000 μm; the ion storage layer is a zinc electrode ion storage layer with a thickness of 500 nm.

[0083] The preparation method of the above-mentioned self-powered electrochromic device is as follows:

[0084] An inorganic electrochromic layer is prepared on the surface of the first transparent conductive substrate to obtain a first transparent conductive substrate@inorganic electrochromic layer; an aqueous solution of tungsten trioxide quantum dots is ultrasonically sprayed onto the surface of the first soda-lime glass@indium tin oxide transparent conductive substrate. The spraying height of the ultrasonic spraying is 2.5 cm, the spraying flow rate is 0.1 mL / min, and the spraying times are 100 times, obtaining a first soda-lime glass@indium tin oxide transparent conductive substrate@tungsten trioxide quantum dot electrochromic layer, which is placed in a vacuum drying oven with a vacuum degree of -0.05 MPa and 60 °C for drying for 12 h.

[0085] The preparation method of the tungsten trioxide quantum dot solution is as follows: 0.02 mol of sodium tungstate is mixed and stirred with 40 mL of water, and then mixed and stirred with 5 mL of concentrated hydrochloric acid with a molar concentration of 12 mol / L and a mass fraction of 36% for 5 min. First, the precipitate is washed with water, and then washed with absolute ethanol until the pH > 3 to obtain tungstic acid; then tungstic acid is mixed with 40 mL of ethylene glycol and stirred at 90 °C until the precipitate dissolves and a transparent and colorless solution is obtained, then the heating is stopped. Then the mixture is transferred to a polytetrafluoroethylene-lined autoclave with an internal volume of 100 mL, and then a solvothermal reaction is carried out in a blast oven at 180 °C for 48 h. Then, ethylene glycol in the solution is removed by dialysis to obtain an aqueous solution of tungsten trioxide quantum dots.

[0086] An ion storage layer is prepared on the surface of a common glass substrate to obtain a common glass substrate@ion storage layer; the zinc foil is polished with sandpaper to remove the zinc oxide on the surface, the zinc foil is placed in a beaker filled with absolute ethanol and ultrasonically cleaned for 15 min, and then dried in an oven at 60 °C for 10 min to obtain the zinc foil; a hollow rectangle is cut out in the middle of the zinc foil to obtain a zinc frame counter electrode, and finally the zinc frame electrode is adhered to the common glass substrate with double-sided tape to obtain a common glass substrate@zinc counter electrode.

[0087] The first soda-lime glass@indium tin oxide transparent conductive substrate@tungsten trioxide quantum dot electrochromic layer and the common glass substrate@zinc counter electrode are sealed with 3M tape to obtain a hollow sandwich structure, and then a zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte is injected into the cavity of the hollow sandwich structure to obtain a self-powered electrochromic device.

[0088] The preparation method of the zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte is as follows:

[0089] 3.73 g of zinc perchlorate, 4.87 g of aluminum perchlorate and 20 mL of propylene carbonate solution are stirred and mixed to obtain the zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte; the concentration of zinc perchlorate in the zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte is 0.5 mol / L; the concentration of aluminum perchlorate in the zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte is 0.5 mol / L;

[0090] Before use, the first sodium calcium glass@indium tin oxide transparent conductive substrate is ultrasonically cleaned with deionized water, acetone, isopropyl alcohol and absolute ethanol for 12 min in sequence, then placed in a vacuum drying oven at 60 °C for drying for 12 h, and then sealed with a plastic film and placed in a drying cabinet for standby; the first transparent conductive substrate is a sodium calcium glass@indium tin oxide transparent conductive substrate subjected to surface treatment by ultraviolet ozone irradiation.

[0091] The physical properties of the tungsten oxide quantum dot electrochromic layer in the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in this example are characterized by using an X-ray diffractometer and a high-resolution transmission electron microscope respectively, and the results are as Figure 2 and Figure 3 shown. It can be seen from the figure that: Figure 2 In, the characteristic peaks of tungsten trioxide quantum dots are not obvious, and only a few strong main peaks appear. This is mainly due to the broadening of the diffraction peaks caused by the too small particle size of the quantum dots. However, by matching with the main peaks at 14° and 28.1°, it can be roughly determined that the prepared tungsten trioxide quantum dots are hexagonal crystal system (PDF#85-2460); Figure 3 In, the particle size of the quantum dots is less than 3 nm. The lattice fringes of tungsten trioxide quantum dots can be clearly seen from the high-resolution transmission electron microscope (HRTEM). Among them, the lattice spacing of 0.25 nm corresponds to the (202) crystal plane of tungsten trioxide quantum dots (PDF#85-2460), which further illustrates that the prepared tungsten oxide is hexagonal crystal phase. Thus, it can be seen that the present invention has successfully synthesized a tungsten oxide quantum dot electrochromic layer.

[0092] The electrochromic performance of the tungsten oxide quantum dot electrochromic layer in the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in this example is tested, and the scheme is as follows:

[0093] Using the zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte in Example 1 as the electrolyte; using the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer as the working electrode; using a zinc foil as the counter electrode, voltages of 1.5 V, 0.8 V, and 0.2 V were applied respectively, and the transmittance of the tungsten oxide quantum dot electrochromic layer to light of different wavelengths at different voltages was tested as Figure 4 shown; and the response time graph of the tungsten oxide quantum dot electrochromic layer when a voltage of 1.5 V and 0.2 V was applied at a wavelength of 633 nm light was as Figure 5 shown.

[0094] It can be seen from Figure 4 that: the tungsten oxide quantum dot electrochromic layer has excellent electrochromic performance. When the voltage is 1.5 V, it is in the bleached state, and when it is 0.2 V, it is in the colored state, and it has a large modulation range. The modulation range of the tungsten oxide quantum dot electrochromic layer for 633 nm wavelength light is 94.6% (the difference in transmittance between 1.5 V and 0.2 V); the modulation range for 1200 nm wavelength light is 91.2%; and at 0.8 V, the tungsten oxide quantum dot electrochromic layer has dual-band modulation performance, that is, it has a high transmittance in the visible light and a very low transmittance in the near-infrared; this indicates that in addition to the high transmittance state and high blocking rate state in the near-infrared and visible light at 1.5 V and 0.2 V, the prepared tungsten oxide quantum dot electrochromic layer of the present invention can also achieve blocking most of the near-infrared light while transmitting most of the visible light at 0.8 V, thereby realizing the independent regulation of visible light and near-infrared light.

[0095] It can be seen from Figure 5 that the response time of the tungsten oxide quantum dot electrochromic layer is: the coloring time is 6.4 s, and the bleaching time is 4.2 s. Thus, it can be seen that the tungsten oxide quantum dot electrochromic layer provided in the examples of the present invention has a fast response speed to 633 nm wavelength light.

[0096] For the test of the thermoelectric conversion performance of the tungsten oxide quantum dot electrochromic layer in the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in this example, the scheme is as follows:

[0097] The non-constant temperature H-type electrolytic cell was used for the test. The non-constant temperature H-type electrolytic cell consists of two chambers. One end chamber is the hot end, where the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten trioxide quantum dot electrochromic layer is placed, and the other end chamber is the cold end, where a zinc metal counter electrode is placed. The electrolyte is 0.5 mol / L zinc perchlorate@aluminum perchlorate@propylene carbonate electrolyte; a temperature difference (ΔT) is formed by adjusting the temperature of the water bath used for the hot end water circulation and keeping the cold end at room temperature. The electrochemical workstation records a series of thermoelectrochemical signals during the thermoelectric performance test; before the test, first based on a current density of 0.1 mAg -1The constant current discharge method embeds electrolyte ions into tungsten trioxide quantum dots in advance until the voltage reaches 0.2V and is in the colored state. Then, heat the first sodium calcium glass @ indium tin oxide transparent conductive substrate @ tungsten trioxide quantum dot electrochromic layer to the set temperature, while keeping the zinc metal counter electrode stable at room temperature, and construct a stable temperature difference at both the hot and cold ends. Then, record the graph of the relationship between the output voltage and time of the system at different temperatures, and the thermoelectric potential graph (Seebeck coefficient graph) of the system obtained by fitting calculation as Figure 6 shown. It can be seen from the figure that as the temperature difference increases, the output voltage of the system increases; at a temperature difference of 25K in the system, the output voltage of the system can reach 1.18V; through the thermoelectric potential graph of the system obtained by fitting calculation, the Seebeck coefficient is 15.4mV / K, indicating that tungsten trioxide quantum dots have excellent thermoelectric conversion ability. At the hot end, almost all the ions embedded in the electrode material are completely deintercalated and diffuse to the cold end to generate a potential difference. Thus, it can be seen that the tungsten trioxide quantum dot electrochromic layer of the present invention can achieve thermoelectric conversion.

[0098] Perform electrochromic performance tests on the self - powered electrochromic device prepared in this example. Apply voltages of 1.5V, 0.8V, and 0.2V to the self - powered electrochromic device, and measure the transmittance spectra of the self - powered electrochromic device as Figure 7 shown; and the response times of the self - powered electrochromic device at 633nm wavelength light when applying voltages of 1.5V and 0.2V as Figure 8 shown.

[0099] It can be seen from Figure 7 that the self - powered electrochromic device still has excellent dual - band electrochromic performance. When the voltage is 1.5V, it is in the bleached state, and when it is 0.2V, it is in the colored state, and it still has a large modulation range. The modulation range of the device at 633nm is 80.2% (the difference in transmittance between 1.5V and 0.2V), and the modulation range of the device at 1200nm is 52.8%; and in addition to having high transmittance states and high blocking rate states in the near - infrared and visible light at 1.5V and 0.2V, the self - powered electrochromic device prepared by the present invention can also achieve blocking most of the near - infrared light and transmitting most of the visible light at 0.8V, so as to realize the independent regulation of visible light and near - infrared light.

[0100] It can be seen from Figure 8 that the response time of the self - powered electrochromic device is: the coloring time at 633nm is 5.4s, and the bleaching time is 3.4s. Thus, it can be seen that the electrochromic response speed of the device prepared by the present invention is fast.

[0101] Take pictures of the self - powered electrochromic device at three voltages with a digital camera, and the results are as Figure 9As shown in the figure. It can be seen from the figure that at 1.5 V and 0.2 V, near-infrared and visible light have high transmittance states and high blocking rate states. At 0.8 V, most of the near-infrared light is blocked while most of the visible light is transmitted, thus realizing the independent regulation of visible light and near-infrared light.

[0102] The cyclic performance of the self-powered electrochromic device prepared in this example was tested by using an arbitrary constant potential staircase wave method (maintaining the voltage at 1.5 V for 15 s; maintaining the voltage at 0.2 V for 30 s). The results are as Figure 10 shown in the figure. It can be seen from the figure that after 10,000 cycles, the self-powered electrochromic device still has a capacity retention rate of 99.75%, indicating that the self-powered electrochromic device of the present invention has excellent cycle life.

[0103] The thermoelectric conversion performance of the tungsten oxide quantum dot electrochromic layer in the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in this example was tested. The scheme is as follows:

[0104] The thermoelectric conversion performance of the self-powered electrochromic device prepared in this example was tested. The test scheme is as follows: The assembled device was placed between two semiconductor thermostats, a temperature difference was applied to the upper and lower surfaces, and the change in the output voltage of the device was measured. The test results are as Figure 11 shown in the figure. It can be seen from the figure that the blue line in the figure is the self-charging curve of the self-powered electrochromic device itself, that is, after the device discharges and embeds ions, the ions will slowly escape from the electrode material without applying a temperature difference, causing the voltage to increase; the red line is the output voltage of the self-powered electrochromic device system at a temperature difference of 25 K. The self-powered electrochromic device of the present invention can generate an output voltage of 0.92 V through thermoelectric conversion at a temperature difference of 25 K. This part of the converted voltage will be stored in the device and can be used for its own photothermal regulation and external power supply, indicating that the device of the present invention has excellent thermoelectric conversion and storage capabilities.

[0105] In order to test the external power supply ability of the self-powered electrochromic device prepared in this example, we externally connected a 65 kΩ resistor to the device at a temperature difference of 25 K, and the device was used for thermoelectric conversion to supply power to the resistor. Then, the resistor was removed and the 25 K temperature difference was removed in sequence, and the change relationship of the output voltage with time was obtained as Figure 12As shown. It can be seen from the figure that: The self - powered electrochromic device prepared in this example tends to be stable at 0.5 h, and can continuously supply power to a 65 kΩ resistor for 3 hours. After removing the resistor at 3 h, there is no load consumption. Under the action of the temperature difference, the thermoelectric conversion voltage of the device continues to increase, and the output voltage of the self - powered electrochromic device increases rapidly and finally tends to be stable; after removing the temperature difference, the voltage can still be maintained, indicating that the electrical energy generated by the thermoelectric conversion of the self - powered electrochromic device is almost balanced with the electrical energy consumed externally, and it has the ability to supply power externally for a long time.

[0106] Replace the external resistor with an LED bulb, and use a digital camera to record the state of the LED bulb. The result is as Figure 13 shown. It can be seen from the figure that: The LED bulb is lit because after removing the external resistor, the output voltage of the self - powered electrochromic device increases rapidly and finally tends to be stable. Connecting the stabilized self - powered electrochromic device to the LED bulb can easily drive the bulb to light up. Thus, it can be seen that the self - powered electrochromic device prepared by the present invention has excellent thermoelectric conversion and storage capabilities.

[0107] Example 2

[0108] The difference between the present invention and Example 1 is that: During the preparation process of the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer, the number of ultrasonic spraying times is 50 times, obtaining the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer, and the rest is the same as in Example 1.

[0109] According to the same test method, the electrochromic performance test and thermoelectric conversion performance test are carried out on the tungsten oxide quantum dot electrochromic layer in the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in Example 2. The results show that: When the number of ultrasonic spraying times is 50 times, the obtained tungsten oxide quantum dot electrochromic layer still has dual - band regulation performance at 0.8 V, but the modulation range is decreased compared with the tungsten oxide quantum dot electrochromic layer in Example 1. The modulation range of the tungsten oxide quantum dot electrochromic layer at 633 nm is 73.2%, and at 1200 nm is 84.6%. The thermoelectric conversion performance is almost the same as that of the tungsten oxide quantum dot electrochromic layer in Example 1.

[0110] Example 3

[0111] The difference between the present invention and Example 1 is that: During the preparation process of the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer, the number of ultrasonic spraying times is 150 times, obtaining the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer, and the rest is the same as in Example 1.

[0112] The electrochromic performance and thermoelectric conversion performance of the tungsten oxide quantum dot electrochromic layer in the first sodium calcium glass@indium tin oxide transparent conductive substrate@tungsten oxide quantum dot electrochromic layer prepared in Example 3 were tested according to the same test method. The results showed that when the number of ultrasonic spraying times was 150 times, the tungsten oxide quantum dot electrochromic layer still had dual-band regulation performance at 0.8 V, but the modulation range decreased compared with that of Example 1. The regulation range of the tungsten oxide quantum dot electrochromic layer at 633 nm was 89.7%, and the regulation range at 1200 nm was 82.2%; the thermoelectric conversion performance was slightly different from that of Example 1.

[0113] In summary, the self-powered electrochromic device provided by the present invention has excellent thermoelectric conversion and storage performance; it broadens the application scenarios of electrochromic devices. It can not only perform photothermal regulation on sunlight, but also utilize the temperature difference between indoor and outdoor for thermoelectric conversion and storage. The generated voltage can be used for the regulation of the device itself or external power supply, making up for the defect that electrochromic devices need an external power supply for regulation and reducing energy consumption.

[0114] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A self - powered electrochromic device, comprising a first transparent conductive substrate, an inorganic electrochromic layer, an electrolyte layer, an ion storage layer, and a common glass substrate arranged in sequence; The material of the inorganic electrochromic layer comprises one or several of tungsten oxide quantum dots, titanium oxide quantum dots, prussian blue quantum dots, and vanadium oxide quantum dots.

2. The self - powered electrochromic device according to claim 1, characterized in that, The first transparent conductive substrate comprises a transparent substrate and a conductive layer attached to the surface of the transparent substrate; the conductive layer of the first transparent conductive substrate is in contact with the inorganic electrochromic layer; the common glass substrate is in contact with the ion storage layer.

3. The self - powered electrochromic device according to claim 2, wherein The conductive layer in the first transparent conductive substrate independently comprises one or several of indium tin oxide conductive layer, fluorine - doped tin oxide conductive layer, and aluminum - doped zinc oxide conductive layer.

4. The self - powered electrochromic device according to claim 2 or 3, characterized in that, The sheet resistance of the conductive layer of the first transparent conductive substrate is independently 5 - 450 Ω / square.

5. The self - powered electrochromic device according to claim 2, wherein The thickness of the conductive layer of the first transparent conductive substrate is independently 50 - 1500 nm.

6. The self - powered electrochromic device according to claim 1, wherein The cations in the electrolyte layer include H + , Li + 、Zn 2+ , K + and Al 3+ One or more of the .

7. The self-powered electrochromic device according to claim 1, wherein The ion storage layer comprises one or several of metal electrodes, polyaniline electrodes, tungsten oxide electrodes, and prussian blue electrodes.

8. The self-powered electrochromic device according to claim 1, wherein, The thickness of the inorganic electrochromic layer is 100 - 1500 nm; the thickness of the electrolyte layer is 50 - 1000 μm; the thickness of the ion storage layer is 100 - 1000 nm.

9. The preparation method of the self - powered electrochromic device according to any one of claims 1 - 8, comprising the following steps: Prepare an inorganic electrochromic layer on the surface of the first transparent conductive substrate to obtain a first transparent conductive substrate @ inorganic electrochromic layer; Prepare an ion storage layer on the surface of the common glass substrate to obtain a common glass substrate @ ion storage layer; Seal the first transparent conductive substrate @ inorganic electrochromic layer and the common glass substrate @ ion storage layer to obtain a hollow sandwich structure, and then inject an electrolyte into the cavity of the hollow sandwich structure to obtain a self - powered electrochromic device.

10. The application of the self - powered electrochromic device according to any one of claims 1 - 8 or the self - powered electrochromic device obtained by the preparation method according to claim 9 in the fields of electrochromic smart windows, new display technologies, distributed energy storage, or secondary batteries.

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