KR100806694B1 - Fabrication method of Electrochromic coating solution and its coating method - Google Patents

Abstract

The present invention dissolves tungsten metal powder or tungstic acid powder in hydrogen peroxide solution; Heating to remove excess water and hydrogen peroxide; And a method for producing an electrochromic coating material mixed with any one of an organic solvent including methanol, ethanol, propanol, isopropanol, and the like. The present invention is also coated on the glass substrate coated with a transparent conductive film by selecting one of dipping (dip), spin coating and spray coating, and heat-treated at a temperature of less than 500 ℃ amorphous coating A method for coating an electrochromic coating material coated with a tungsten film.

Therefore, according to the present invention, an electrochromic coating material manufactured at a high cost by solving the problems of the electrochromic coating material, which is manufactured at a high cost and has low coating efficiency and performance, is manufactured at low cost, and has excellent coating property and electrochromism performance. A manufacturing method and a coating method thereof can be obtained.

Electrochromic, electrochromic coatings, tungsten oxide films, electrochromic materials.

Description

Manufacturing method of electrochromic coating material and coating method thereof {Fabrication method of Electrochromic coating solution and its coating method}

The present invention relates to a method for producing an electrochromic coating material. More specifically, the present invention dissolves tungstic acid or tungsten metal powder in hydrogen peroxide water, and removes excess water and hydrogen peroxide by adjusting the reaction temperature between 40 ℃-80 ℃ on a rotary concentrate or heating plate, to remove the transparent orange reactant The present invention relates to a method for producing an electrochromic coating material which is synthesized and mixed with a solvent such as ethanol to a desired concentration, and a coating method thereof.

In general, electrochromism means that when an external current is applied to a substance, the composition of the substance is changed by electrochemical cyclization (anode reaction) and oxidation (cathode reaction), thereby changing the color of the material reversibly. The phenomenon is generally colorless when the external electric field is not applied, but color is indicated when the electric field is applied.

The electrochromic reaction phenomenon has been applied to manufacture display devices, smart glasses, and the like, and as the electrochromic material, vanadium pentaoxide, cobalt oxide, tungsten oxide, tungsten molybdenum oxide, and fluoride glass are mainly used. Electrochromic materials (electrochromic materials) are characterized by the color change by the applied voltage, the electrochromic materials are returned to the original color when the applied voltage disappears or the polarity is reversed.

The most widely used electrolytic material so far is tungsten oxide (WO ₃ ). The tungsten oxide has high ion mobility and generates light having a wavelength corresponding to the visible light region.

In order to form a tungsten oxide thin film on a glass substrate, a coating solution is synthesized, and an electrochromic thin film is formed by chemical solution methods such as spin coating, dip coating, and spray coating.

As described above, an electrochromic thin film such as tungsten oxide undergoes a reversible color change by the application of an electric field or an electric current. Such a color change can be divided into a positive electrode electrochromic material that changes positively and a negative electrode electrochromic material that changes negatively. Tungsten oxide is a typical anode electrochromic material. Tungsten oxide becomes blue tungsten or tungsten oxide compound when a negative electric field is applied in an electrolyte solution containing protons or lithium ions. This is called reduction coloring and such an electrochromic material is called an anode electrochromic material. In contrast, nickel oxide or cobalt nickel is colored when a positive electric field is applied. This is called oxidation coloring and is called a negative electrode electrochromic material.

And the method of forming a tungsten oxide thin film is the most typical method is a coating method using a vacuum deposition equipment, such as deposition or sputtering, which can be called a physical coating method. In addition, a chemical vapor deposition (CVD) method of reacting chloride at a high temperature may be considered. A uniform thin film may be obtained by such a coating method, and a coating process may be performed at a relatively low temperature, but a very expensive coating equipment should be used. There is a disadvantage.

In addition to the coating method described above, a sol-gel coating method has been developed for coating with a chemical solution, which is spin coating using a coating solution to coat the substrate, and a method of immersing and removing the substrate in the coating solution. It is mainly used as a dip coating to spray by spray and spray coating to spray the solution by using a nozzle.This coating has the advantage of being able to be coated using an inexpensive coating apparatus. In coating, coating is possible at relatively low temperatures.

In addition, in the case of the coating solution of tungsten oxide, it is common to use a precursor such as tungsten chloride or tungsten oxychloride in a solvent such as ethanol, but in this case, a material such as tungsten chloride or tungsten oxychloride is expensive.

In addition, the conventional tungsten oxide coating solution was synthesized by first dissolving the tungsten metal powder in 30% hydrogen peroxide water, and then adding ethanol and evaporating at 80 ° C. until milky white became a transparent orange color. The amount was adjusted to obtain the appropriate viscosity for the dip coating. In addition, Na ₂ WO ₄ is ion-exchanged to remove sodium ions, reacted with hydrogen peroxide solution, refluxed with acetic acid, and dried in vacuo at 55 ° C. to give a stable solid acetylated peroxotungstic acid. In the case of tungsten metal powder, it is dissolved in 30% hydrogen peroxide solution, 100% acetic acid is added, then it is refluxed at 55 ° C. and vacuum-dried at 60 ° C. to synthesize pale yellow acetylated perox tungstate. Is implemented in such a way. Tungsten oxide is dissolved in ethanol to synthesize a tungsten oxide coating solution and coated with a dip coating method to produce a tungsten oxide thin film. John P. Cronin et al. In U.S. Patent No. 5,525,264 show that oxalic acid, malonic acid, glutaric acid, apitetic acid, ethylenedimitateacetic acid, When a small amount of glycerol, formamide and the like is added within 10%, it was found that the reaction rate is fast during coloring and decolorization.

It is easy to dissolve tungsten powder or tungstic acid in hydrogen peroxide water, but water contained in hydrogen peroxide or unreacted hydrogen peroxide causes problems in coating tungsten thin films. For example, when water is present, a glass substrate coated with a transparent transparent conductive film has a problem in that it is difficult to form a thin film by forming water droplets without coating the coating solution on the substrate due to hydrophilic properties.

Therefore, water or unreacted hydrogen peroxide must be removed. In the conventional case, alcohol is first added and then reacted at 80 ° C. to induce a milky white reactant to be a transparent orange color. However, such a reaction does not easily occur. There is a problem that the reactants are insoluble in ordinary solvents. In addition, the synthesis of acetylated peroxungstic acid is added with acetic acid to react, reflux and vacuum drying and filtering. Synthesis method described in US Patent No. 5,525,264 varies depending on the melting temperature and boiling point of the additive, but there is a disadvantage that the organic matters are decomposed and do not fly at below 200 ° C.

In addition, in the conventional case, as a method of synthesizing a tungsten oxide coating solution, a tungsten metal powder or tungstic acid is dissolved in hydrogen peroxide solution, and then transparent to obtain a uniform thin film by a coating method such as spin coating, dip coating, and spray coating. Excess water and hydrogen peroxide have to be removed to form a film on the substrate glass coated with the conductive film. When removing the excess water and hydrogen peroxide, if the reaction temperature is not controlled, a compound in which water molecules are bonded to tungsten oxide is produced. Tungsten hydrate does not dissolve in solvents such as ethanol, which is not suitable as a coating solution.

Therefore, the present invention has been proposed to solve the above problems, and an object of the present invention is to dissolve tungsten metal powder or tungstic acid powder in hydrogen peroxide (about 30%), and then evaporate water, The present invention is to provide a method for producing an electrochromic coating material which is mixed with a solvent to have a desired concentration and prepared as a tungsten oxide coating solution.

Another object of the present invention is to replace excess expensive raw materials such as chloride or alkoxide, and dissolve tungstic acid or tungsten metal powder in hydrogen peroxide, and adjust the reaction temperature between 40 ℃ and 80 ℃ on a rotary concentrate or heating plate. To provide a method for producing an electrochromic coating material comprising the step of removing hydrogen peroxide, synthesizing a transparent orange reactant, and mixing to a desired concentration in a solvent such as ethanol.

Still another object of the present invention is to prepare an electrochromic coating material by the method described above, and to heat-process at a temperature of less than 500 ℃ by dipping or spin coating and spray coating the prepared coating material on a glass substrate coated with a transparent conductive film To provide an electrochromic coating material coating method for coating an amorphous tungsten oxide film.

It is still another object of the present invention to form an electrochromic oxide thin film having a thickness of 200 nm to 300 nm with a single coating, thereby adjusting the transmittance difference to 80% in visible light having a wavelength of 633 nm with the electrochromic layer. It is to provide a method of coating an electrochromic coating material for coating a tungsten oxide film possible.

In order to achieve the above object, the present invention dissolves tungsten metal powder or tungstic acid powder in hydrogen peroxide water, and removes excess water and hydrogen peroxide, in an organic solvent containing methanol, ethanol, propanol, isopropanol, etc. Provided are a method for producing an electrochromic coating material mixed with any one and a coating method thereof.

To this end, in the present invention, the tungsten oxide hydrate is not formed by adjusting the reaction temperature at 60 ° C.-80 ° C. in a tungsten oxide solution dissolved in hydrogen peroxide solution to form a transparent coating solution that is soluble in a solvent such as ethanol. Tungstic acid is formed, and the peroxo tungstic acid is dissolved in an organic solvent such as ethanol to have a concentration of 0.1M-1M to synthesize a transparent and orange coating solution. Then, the coating solution was coated with a transparent conductive film coated glass substrate by dipping the drawing rate to 50-200 mm / min, dried on a heating plate or drying oven at 100 ° C., and then heat-treated at less than 500 ° C. to obtain desired tungsten oxide. Form a thin film.

Hereinafter, specific examples of the manufacturing method of the electrochromic coating material and the coating method thereof according to the present invention and the effects thereof will be described in detail.

[Step A]

18.353 g of 0.1 mol tungsten (W) powder is added to a beaker containing 80 ml of hydrogen peroxide solution and dissolved. At this time, the hydrogen peroxide solution is preferably 10% to 50%. In this stage, the rapid exothermic reaction occurs and oxygen gas is generated and there is a risk of explosion, so it is stable to cool the beaker with ice and keep it below 10 ° C. After mixing for about 1 hour or more, the metal tungsten powder is completely dissolved to obtain a transparent solution. In order to remove excess water and hydrogen peroxide, the reaction is maintained until 20 ml of clear solution remains while maintaining on a high temperature plate of 40 ° C. to 80 ° C., preferably about 60 ° C., for about 2-4 hours. If the temperature is too high, yellow precipitates or white precipitates are produced, which are tungsten oxide hydrates (shown in graphs 1 and 2) and are insoluble in alcohol. In addition, 20 ml of the resulting orange transparent product can be dissolved in alcohol as a tungsten peroxide compound, and tungsten oxide coating solution is synthesized by adding 80 ml of ethanol.

[Step B]

Since 20 ml of tungsten peroxide compound synthesized in step A has a concentration of 0.1 mol, the addition of 80 ml of ethanol results in 1 M of tungsten oxide coating solution, and the addition of 180 ml results in 0.5 M of coating solution. The concentration of the tungsten oxide coating solution can be adjusted to about 0.1M-1M by adjusting the volume of alcohol added as described above, and the concentration of the coating solution controls the viscosity of the solution and the thickness of the coated film as shown in Graph 3 below. Will be the argument.

[Step C]

Immerse the glass substrate coated with the transparent conductive film (for example, ITO coated glass, surface resistance 10 ohm) in the coating solution synthesized in steps A and B and pull it at a constant speed (50ml / min-200ml / min) The solution on the back side is wiped off with ethanol and heated for 10 minutes on a high temperature plate of 50 ° C. to 100 ° C., preferably 100 ° C. to form a gel film. When heated at 300 ° C. for 1 hour, as shown in Graph 3, it is possible to coat an amorphous tungsten oxide film of 210 nm when coated at a rate of 100 ml / min using a 1 M concentration solution.

[Step D]

Coating by the dipping method as in step C, and changing the dry film to a heat treatment temperature of 100-500 ℃ it is possible to form a tungsten oxide film on the amorphous phase below 300 ℃, and above it is possible to coat a crystalline tungsten oxide film. .

[E stage]

Using a solution synthesized in steps A and B, and coated with ITO-coated PET, PI, and the like using a bar coater, and heat-treated at less than 200 ℃ can be produced a tungsten oxide coated film on the amorphous. In the case of PET, the heat treatment should be performed at a temperature below 130 ° C.

Using a tungsten oxide coated polymer or glass substrate on the amorphous coating coated above, a substrate coated with an ion storage layer such as nickel oxide, cobalt oxide, cerium oxide, or Prussian blue, and a liquid containing lithium ions therebetween Electrolytic, gel electrolyte, and solid film electrolyte layers may be formed and sealed to form an electrochromic device.

Next, the embodiment of the present invention will be described in more detail with reference to the experimental results graph for the above embodiment.

In the tungsten oxide coating solution, a thin film cannot be formed when a polar water is used as a solvent to form a thin film on a glass substrate coated with a transparent conductive film. When the tungsten oxide coating solution is synthesized by dissolving in tungsten powder or tungstic acid as a starting material in hydrogen peroxide water, the tungsten oxide thin film is not easily formed due to excess water and residual hydrogen peroxide. In order to solve this problem, a process for removing excess water and hydrogen peroxide is required. To this end, acetic acid is generally added and dried in vacuo, acetylated peroxotungstic acid (solid) is produced and dissolved in a solvent such as ethanol.

However, the electrochromic coating material manufacturing method according to the present invention is heated to remove excess water and hydrogen peroxide at 40 ℃-80 ℃, while controlling the reaction rate, while maintaining a temperature of 40 ℃-80 ℃ using a rotary concentrator Vacuum can be used to remove excess water and hydrogen peroxide. In this case, if the temperature is not well controlled, the reaction may occur rapidly to form tungsten oxide hydrate. As shown in Graph 1, the product is yellow and does not dissolve in water or ethanol. In addition, as shown in Graph 2, a milky white product is formed, which also cannot be used as a coating solution because it is not dissolved in a tungsten oxide hydrate-based compound. In order to solve this problem, by controlling the temperature well at 40-80 ° C to remove 80vol% of excess water and hydrogen peroxide, insoluble tungsten oxide hydrate is not formed, and it is soluble in solvents such as ethanol and methanol. Preference is given to synthesizing xo tungstic acid.

Graph 1.XRD (X-Ray Diffraction) Pattern of Dry Powder of Yellow Product in Tungsten Solution

Graph 2. XRD Pattern of Dry Powder of White Product in Tungsten Solution

The reaction between the metal tungsten powder and the tungstic acid and hydrogen peroxide is an exothermic reaction, and especially in the case of the metal tungsten powder, the reaction is violent and there is a risk of explosion. It is preferable to keep the reaction temperature below 10 ℃ in order to cause the reaction to occur slowly in order to eliminate the risk of such explosion. However, if the temperature is too low, the reaction rate is too slow to take a long reaction time.

As another method, there is a method in which a small amount of the metal tungsten powder and the hydrogen peroxide solution are added and reacted, and then a small amount is added again. For this purpose, while supplying hydrogen peroxide to the reactor little by little through a dispenser, it is also preferable to inject the metal tungsten powder little by little into the reactor.

Generally, after tungsten is dissolved in hydrogen peroxide water, organic acid such as acetic acid or propionic acid is added to chelate tungsten to form a stable compound in order to form a tungsten hydrogen peroxide reactant, and dried to obtain a solid powder compound. It is used as a coating solution by dissolving it in alcohols having low carbon, such as methanol, ethanol, propanol, isopropanol or a mixture thereof at room temperature. However, this process can stably obtain the electrochromic tungsten oxide coating solution, but there are disadvantages in that a process such as addition of organic acid of acetic acid or propionic acid, vacuum drying, and filtering is added.

Therefore, in the present invention, excess water and hydrogen peroxide water, which have a bad effect on the coating process without the addition of the organic acid, are removed by heating, and the remaining tungsten hydrogen peroxide reactant is dissolved in an alcohol having a low carbon number at room temperature to use as a coating solution. do. In addition, alcohols having a low carbon number have a low evaporation temperature of 120 ° C. or lower, and therefore it is preferable that an electrochromic layer of amorphous metal oxide can be formed even at a low temperature heat treatment.

In addition, U.S. Patent No. 5,525,254 shows that cracks occur when the thickness of the metal oxide becomes thick, and the ion transport rate is faster in the case of the porous membrane than in the case of the dense membrane. Techniques for implementing are described. However, when the present invention is coated with a coating solution of the tungsten peroxide compound itself, it is possible to coat a thickness of 300nm and the amorphous membrane is considered to be suitable for the electrochromic properties because it has a certain porosity, accordingly organic material for porosity It is determined that the step of adding the component is not necessary.

In order to form the electrochromic coating layer, a transparent conductive film coated glass is used. Generally, tin-doped indium oxide film (ITO) coated glass is used. As the surface resistance is less than 10 ohms, the movement speed of ions can be increased, so a transparent conductive film having low resistance and high visible light transmittance is required. Therefore, in the present invention, a transparent conductive film having a thickness of about 160 nm to 220 nm and having a resistance of 15 ohms or less and a transmittance of 85% or more is selected. However, ITO membranes have problems of poor chemical durability and high price.

In order to solve the problem, the present invention can use a glass on which a fluorine-doped tin oxide (FTO) film coated with a chemical vapor deposition method in inline is formed. In the case of the FTO film, since the coating glass having a resistance of 10 ohms or less is commercially available, it can be used as a transparent conductive film substrate for the electrochromic, and the FTO film has the advantages of low chemical resistance and good chemical durability.

In general, the substrate coated with the transparent conductive film forms a tungsten oxide electrochromic layer by a dip coating method, cuts the substrate into a substrate having a desired size (10 cm × 10 cm, 30 cm × 30 cm), and then places it on the substrate holder of the dip coater. After dipping it into a bath filled with tungsten oxide coating solution, it is pulled out of the bath at a constant speed so that the tungsten oxide solution is coated on the transparent conductive film coating glass.

At the time of coating, the atmosphere is coated under a general air atmosphere, and both sides of the coating are coated after the coating, thereby wiping away the portion where the transparent conductive film is not coated. Thereafter, the plate is dried for about 10 minutes in a plate or oven heated to about 100 ° C. to allow the solvent to volatilize to form a gelled film. However, the solvent component and the organic substance still remain, so the heat treatment should be performed at a higher temperature. If the temperature is too low, the film tends to peel off easily because the bonding force between the substrate and the film is weak, and if the heat treatment is performed at a high temperature, the tungsten oxide crystallizes to form a crystalline film, and the electrochromic properties deteriorate. Tends to be.

In addition, the thickness of the coating film, as shown in the graph 3, it can be seen that varies depending on the viscosity of the coating solution, the viscosity of the 0.1 molar concentration was 2.2cP and the thin film thickness was 27nm, which increases linearly with the concentration of the solution In the case of 1 molar concentration, the viscosity is 8.3 cP and the film thickness is 210 nm. The thicker the thin film, the more active sites the ions in the electrolyte can enter into the electrochromic thin film in the electrochromic device, thereby increasing the capacity of the electrochromic, thereby increasing the contrast of color.

Graph 3. Variation of Viscosity and Film Thickness with Tungsten Oxide Coating Solution

In addition, it can be seen from Graph 4 that the crystal phase of the thin film varies depending on the heat treatment temperature. The amorphous tungsten oxide thin film is formed below 300 ° C, but the crystalline tungsten oxide thin film is formed above 400 ° C, and when the heat treatment temperature is 500 ° C, the crystallinity becomes larger due to the higher crystal peak intensity. Able to know. In the case of the electrochromic device, it is preferable that the amorphous tungsten oxide film be heat-treated at 300 ° C. or lower because ions can easily enter and exit ions.

Graph 4. Crystal phase change with heat treatment temperature after coating on ITO glass substrate using tungsten oxide coating solution

Next, a tungsten oxide thin film coated on an ITO glass substrate using a tungsten oxide coating solution and heat-treated at 300 ° C., using Ag / AgCl as a reference electrode in a polycarbonate (PC) electrolyte in which 1M LiClO 4 was dissolved, and platinum wire Cyclic voltammetry (CV) curve when used as a counter electrode was measured 100 times. Applying a negative voltage intercalates the lithium ions in the electrolyte into the tungsten oxide thin film, and supplies electrons to form a reducing reaction with LixWO3, which is colored blue and -0.7 mA / cm2 at -1 V. It exhibited a current density, and the lithium ion injected at -0.3 V was released again and oxidized to WO ₃ to become transparent, showing a current density of 0.6 mA / cm ² . The longer the cycle, the smaller the sites that can be implanted and exited.

Graph 5. Cyclic Voltammitt curve of WO ₃ thin film heat treated at 300 ° C

In addition, the change in transmittance in the visible region was observed using a 633 nm laser in situ while evaluating the cycle voltamite characteristics, and showed a transmittance of 90% in the bleached state. colored state) showed a transmittance of 5%. It can be seen that the transmittance during coloring with the cycle increases to about 10%, but the change in transmittance during coloring and decoloring is very high at 80%, as shown in Graph 6.

Graph 6. In Situ Visible Light Transmittance Change of WO ₃ Thin Film Treated by 300 ℃

The electrochromic thin film is formed using an electrochromic coating material, which is a tungsten oxide coating solution prepared as described above, and a counter such as cerium oxide, vanadium pentoxide, titanium oxide, or nickel oxide is coated on a glass substrate coated with a transparent conductive film. The electrochromic device may be manufactured by coating an electrode and inserting and sealing a solid electrolyte such as a liquid electrolyte or a polymer film in which lithium ion is added to polycarbonate at a concentration of 1 M between the electrochromic layer and the counter electrode. The electrochromic device may be applied to an intelligent window that can adjust the transmittance of visible light by adjusting a voltage, a rear view mirror for automobiles to prevent glare, and glasses that can control the visible light transmittance.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the field of the present invention that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

As described above, the present invention dissolves tungsten metal powder or tungstic acid powder in hydrogen peroxide (about 30%), and then evaporates the water, and mixed with a solvent such as ethanol to have a desired concentration as a tungsten oxide coating solution Provided electrochromic coating material to be produced, and instead of expensive raw materials such as chloride and alkoxide, dissolve tungstic acid or tungsten metal powder in hydrogen peroxide, and adjust the reaction temperature between 60-80 ℃ on the rotary concentration or heating plate Removing excess water and hydrogen peroxide, synthesizing a transparent orange reactant, and mixing to a desired concentration in a solvent such as ethanol to provide a method for producing an electrochromic coating material, to prepare and produce an electrochromic coating material Dipping or spin coating the coated material onto a glass substrate coated with a transparent conductive film And, by spray coating and heat treatment at a temperature of less than 500 ℃ has the effect of providing a coating method for coating an amorphous tungsten oxide film.

Claims (13)

Dissolve tungsten metal powder or tungstic acid powder in hydrogen peroxide, Heating the dissolved product to remove excess water and hydrogen peroxide, The product from which water and hydrogen peroxide water are removed is mixed with any one of the group consisting of methanol, ethanol, propanol and isopropanol so that tungstic acid has a concentration of 0.5M-1M and synthesized into a transparent and orange coating solution. Manufacturing method of electrochromic coating material The method of claim 1, Dissolution of the hydrogen peroxide water Dissolves tungsten metal powder or tungstic acid powder in 10% to 50% hydrogen peroxide Method for producing an electrochromic coating material. The method of claim 1, Removal of excess water and hydrogen peroxide water Remove excess water and hydrogen peroxide by adjusting the reaction temperature between 40 ℃ -80 ℃ on rotary concentrate or heating plate Method for producing an electrochromic coating material. The method of claim 1, Removal of excess water and hydrogen peroxide water Heated to remove excess water and hydrogen peroxide, synthesized as a transparent orange reactant Method for producing an electrochromic coating material. delete delete delete delete Tungsten metal powder or tungstic acid powder was dissolved in hydrogen peroxide solution, the dissolved product was heated to remove excess water and hydrogen peroxide, and the product of water and hydrogen peroxide solution was removed so that tungstic acid had a concentration of 0.5M-1M. , An electrochromic coating material prepared by mixing with any one of the group consisting of propanol, isopropanol and synthesized into a transparent and orange coating solution Selecting and coating one of dipping, spin coating, and spray coating on the glass substrate coated with a transparent conductive film, and heat-treating at a temperature of less than 100 ℃ ~ 500 ℃ coated with an amorphous tungsten oxide film Coating method of electrochromic coating material. The method of claim 9, Selecting and coating one of dipping, spin coating and spray coating on the transparent conductive film-coated glass substrate, and further comprising the step of drying Coating method of electrochromic coating material. The method of claim 9, The electrochromic coating material is coated on the glass substrate coated with the transparent conductive film by dipping, spin coating or spray coating with a thickness of 200 nm to 300 nm. Coating method of electrochromic coating material. The method of claim 9, After coating by adjusting the speed of dipping to 50mm / min-200mm / min, and then dried in a heating plate or drying oven of 50 ℃ ~ 100 ℃, heat treatment at 100 ℃ ~ 500 ℃ Coating method of electrochromic coating material. The method of claim 9, After the heat treatment step, Further comprising forming an amorphous tungsten oxide film at 100 ° C to 300 ° C. Coating method of electrochromic coating material.