KR20170025612A - Microporous polymer membrane for electrochromic device and smart window including the same - Google Patents

Abstract

The present invention relates to an electrochromic device using microporous polymer and a smart window including the same and, more specifically, to an electrochromic device to which a gel polymer electrolyte layer is applied by coating and crosslinking reactive electrolyte on a porous polymer film and a smart window including the electrochromic device. According to the present invention, the electrochromic device increases durability, secures uniform discoloration and long-term stability, and obtains excellent ion conductivity. In addition, the electrochromic device according to the present invention is capable of being manufactured in a large size, thereby being easily applied to the industry of large-sized smart windows in a building.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrochromic device using a porous polymer membrane and a smart window including the electrochromic device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochromic device using a porous polymer membrane and a smart window including the electrochromic device. More particularly, the present invention relates to an electrochromic device applied with a reactive electrolytic solution on a porous polymer membrane followed by crosslinking to form a gel polymer electrolyte layer, Smart window.

An electrochromic device (ECD) refers to a device in which the color of an electrochromic material is changed by an electric oxidation-reduction reaction according to the application of an electric field, thereby changing a light transmission characteristic. In addition, development has been continuously carried out for application to a display device such as a mobile phone, a camcorder, a notebook, and the like, as well as a display such as an electric signboard or an electronic book (e-book). The most successful products that utilize the electrochromic device include a rearview mirror for automatically controlling the glare of light at the rear at night, a smart window that can be automatically controlled according to the intensity of light window. The smart window is changed to a darker color in order to reduce the amount of light when the solar radiation amount is large, and the energy saving efficiency is improved by changing to a bright color on a cloudy day.

The electrochromic device is similar to a battery, and refers to a device in which a thin film of a reducing coloring layer / electrolyte (Li ⁺ , H ⁺ ) / oxidative discoloration layer is formed. The principle of electrochromatography is briefly described. Tungsten oxide, which is a reducing coloring material, is colored when positive ions such as Li ⁺ or H ⁺ and electrons are injected, and becomes transparent when it is emitted. On the other hand, when cations and electrons such as Li ⁺ and H ⁺ are released to nickel oxide or cobalt oxide which is an oxidative coloring material, they are colored, and when they are injected, they become transparent.

Electrolytes used in electrochromic devices exchange charge between the oxidation and reduction layers. Examples of the electrolyte include a solid electrolyte or a liquid electrolyte deposited on the reduction coloring layer.

The solid electrolyte is excellent in terms of stability of the electrochromic device, but has a disadvantage in that it is difficult to commercialize it because the ionic conductivity is low. In order to solve this problem, an electrolyte including an ionic liquid and improved in stability and lifetime has been disclosed. However, it is still difficult to apply the electrolyte to electrolyte leakage, thinning of the device, and processing of film form.

The liquid electrolyte is basically prepared by dissolving an electrolyte lithium salt such as LiClO ₄ in an organic solvent. Organic solvent is volatile and is depleted, there is a liquid leakage problem in the production of a device, the decolorization rate is slow, and organic matter is easily decomposed by repeating coloration and discoloration. Further, it is difficult to maintain the stability of the product due to side reaction with the element constituting material or volume change due to polymerization, and it is disadvantageous in that it can not be made thin and can not be processed in a film form.

At this time, long-term stability can be improved by using a gel-type electrolyte having a high viscosity and little volatility. Korean Patent No. 10-0729500 discloses a gel polymer electrolyte impregnated with an ionic liquid without an organic solvent. However, since the vinyl monomer used as a monomer capable of forming a gel polymer has high reactivity and low storage stability of the electrolyte, There is a problem of deterioration. In addition, when the gel electrolyte is used, the mobility of ions is lower than that of the liquid electrolyte, so that the response speed of the prepared electrochromic device is slow and the color is not dark. Further, the mechanical properties of the gel polymer electrolyte are not sufficient, and it is also difficult to keep the interval between the two electrode discoloring layers constant over a long period of time.

Korean Patent Registration No. 10-0729500.

In order to solve the above problems, the present invention provides an electrochromic device capable of applying a porous polymer membrane and an electrolyte in the form of a gel polymer to the electrochromic device to enhance uniform discoloration and durability, and a method for manufacturing the electrochromic device will be.

Also, the present invention provides an electrochromic device capable of securing long-term stability by using a porous polymer membrane and a gel polymer electrolyte as an electrolyte, capable of obtaining an excellent ion conduction velocity, and capable of being manufactured in a large area, and a method of manufacturing the electrochromic device It has its purpose.

The present invention provides an electrochromic device comprising a reduced color shift layer, an electrolyte layer, and an oxidative color shift layer, the method comprising: stacking a porous polymer layer on a reduced color shift layer;

Applying a reactive electrolytic solution on the porous polymer membrane;

Laminating an oxidative discoloration layer on the electrolyte layer including the porous polymer membrane coated with the reactive electrolytic solution; And

Irradiating the stacked electrochromic device with light to polymerize the electrolyte layer into a gel; And a method for producing the electrochromic device. In addition, the present invention provides an electrochromic device manufactured by the above manufacturing method, and the electrochromic device of the present invention can be applied to a smart window.

The electrochromic device including the gel polymer electrolyte layer based on the porous polymer membrane according to the present invention can improve uniform discoloration and durability, ensure long-term stability, and obtain excellent ionic conductivity.

In addition, since the electrochromic device according to the present invention can be manufactured in a large area, it can be easily applied to a large area smart window industry in a building, and when a glass is broken in a smart window, it prevents splinters of glass, Provide a stable smart window without leakage.

1 is a structural view of an electrochromic device manufactured according to an embodiment of the present invention.
2 is a view illustrating a step of fabricating an electrochromic device manufactured according to an embodiment of the present invention.
FIG. 3 is a photograph of an electrochromic device manufactured according to an embodiment of the present invention before and after the reactive electrolytic solution is injected.
4 is a graph showing oxidation / reduction characteristics and lifetime characteristics of cyclic voltammetry (CV) of an electrochromic device manufactured according to Example 2 of the present invention.
5 is a graph showing the transmittance of the electrochromic device manufactured in Example 2 of the present invention.

Hereinafter, the present invention will be described in more detail. Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the following description, the gist of the present invention is unnecessarily blurred And a description of the known function and configuration will be omitted.

The present invention relates to an electrochromic device capable of applying a gel polymer electrolyte layer including a porous polymer membrane to an electrochromic device to enhance uniform discoloration and durability, and a method for manufacturing the electrochromic device.

The electrochromic device of the present invention refers to a device in which an electric field is applied to change the color of a material by an oxidation or reduction reaction.

The present invention relates to an electrochromic device comprising a red color change layer / an electrolyte layer / an oxidative color change layer

Laminating a porous polymer membrane on the reduction discoloration layer;

Applying a reactive electrolytic solution on the porous polymer membrane;

Laminating an oxidative discoloration layer on the electrolyte layer including the porous polymer membrane coated with the reactive electrolytic solution; And

Irradiating the stacked electrochromic device with light to polymerize the electrolyte layer into a gel;

And a method for producing the electrochromic device.

The porous polymer membrane to be applied to the electrolyte layer of the present invention is capable of improving ionic conductivity by forming pores. The porous polymer membrane may include polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), polyvinylidene fluoride (PVdF) (PT), polymethylmethacrylate (PMMA), polyacrylonitrile (PAN), polyethylene (PE), polypropylene (PP), and the like But is not limited to.

 The solution is mixed with a ketone-based or an amide-based solvent to prepare a polymer solution. The solution is cast on a fixing plate and dried to form a polymer film. The formed polymer film is then extracted The porous polymer membrane can be formed through a process of re-impregnating with a water, alcohol, ether, or hydrocarbon mixed solvent, which is a solvent, to extract the pore forming material.

The polymer and the pore-forming extractant may be mixed at a weight ratio of 40 to 60:60 to 40, and the mixture of the polymer and the pore-forming extract may be contained in an amount of 10 to 30 parts by weight based on 100 parts by weight of the solvent. And it is preferable to maintain the mechanical properties of the porous polymer membrane within the above range, and to increase the pore formation rate, thereby improving the ionic conductivity.

The pore-forming extraction material is not limited as long as it can be dissolved in a solvent to form pores, and phthalate-based compounds that can be chemically uniformly mixed and easily separated are preferable. For example, when the above-mentioned phthalate compound and solvent are removed with a water, alcohol, ether, or hydrocarbon mixed solvent after mixing and casting the butyl phthalate with the polymer resin and the solvent, micropores are formed in the place A porous polymer membrane can be formed. The pore size of the porous polymer membrane may be in the range of 0.001 to 1000 μm, and the porosity may be in the range of 5 to 95%, but is not limited thereto.

In the present invention, the reactive electrolytic solution formed on the porous polymer membrane and formed of gel polymer due to photo-crosslinking may be a mixture containing an electrolyte salt, an organic solvent, a crosslinking agent, a photoinitiator and an additive.

The reactive electrolytic solution may be mixed with 35 to 70% by weight of an electrolyte salt dissolved in an organic solvent, 25 to 60% by weight of a crosslinking agent, 0.1 to 5% by weight of a photoinitiator and 0.01 to 5% by weight of an additive, The ion conductivity is excellent within the range, and the lifetime of the electrochromic device can be maintained for a long time.

The electrolyte salt is inserted into or removed from the electrochromic device to change the oxidation number of the transition metal, thereby changing the transmittance. Preferably, for example, a lithium salt, LiF, LiCl, LiBr, LiI , LiClO 4, LiClO 3, LiAsF 6, LiSbF 6, LiAl0 4, LiAlCl 4, LiNO 3, LiN (CN) 2, LiPF 6, Li ( CF ₃ ) ₂ PF ₄ , Li (CF ₃ ) ₃ PF ₃ , Li (CF ₃ ) _{4 PF 2, Li (CF 3)} 5 PF, Li (CF 3) 6 P, LiSO 3 CF 3, LiSO 3 C 4 F 9, LiSO 3 (CF 2) 7 CF 3, LiN (SO 2 CF 3) 2, _{LiOC (CF 3) 2 CF 2} CF 3, LiCO 2 CF 3, LiCO 2 CH 3, LiSCN, LiB (C 2 O 4) 2, LiBF 2 (C 2 O 4), LiBF 4 , And the like, but the present invention is not limited thereto.

The organic solvent may sufficiently dissociate lithium ions by a large polarity, and thus a carbonate solvent having a high dielectric constant may be used. Specific examples thereof include dimethyl carbonate, diethyl carbonate, di Propylene carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, methylethyl carbonate, ethyl fluoroethyl carbonate, ethylene carbonate, propylene carbonate, But is not limited to, a mixture of one or more selected from the group consisting of propylene carbonate, fluoroethylene carbonate, and butylenes carbonate.

The electrolyte salt may be used in an organic solvent in a concentration range of 0.5 to 1.5 mol (M). The concentration of the electrolyte salt is not particularly limited. However, within the above range, lithium ion mobility is high, So that the performance of the electrochromic device can be further improved.

The crosslinking agent is a resin capable of forming a gel polymer electrolyte by polymerization by a photo-curing reaction with a photoinitiator. It can control the reaction rate and curing degree, and can give excellent ion conductivity by excellent durability. The crosslinking agent is a copolymer containing an acrylate group having a photo-curing group, and examples thereof include ethylene glycol di (meth) acrylate, poly (ethylene glycol) di (meth) acrylate 1,6-hexanediol di (Meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, (Meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa May be used, but the present invention is not limited thereto.

The cross-linking agent preferably has a weight average molecular weight of 200 to 100,000 from the viewpoint of curing degree to form a gel polymer, but is not limited thereto.

The photoinitiator may be at least one compound selected from the group consisting of an acetophenone compound, a benzophenone compound, a thioxanone compound, a benzoin compound, a triazine compound, a oxime compound, etc. Specifically, 2,2'-diethoxy Acetophenone, 2,2'-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyl trichloroacetophenone, pt-butyldichloroacetophenone, 4- Thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, benzoin, benzoin (Trichloromethyl) -s-triazine, 2 - ((4-methylphenyl) ethyl) benzoin ethyl ether, benzoin isopropyl ether, 2,4,6-trichloro- 4,6-bis (trichloromethyl) -s-triazine, 2- (4'-methoxynaphthyl) -4,6-bis (Trichloromethyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) (Trichloromethyl) -s-triazine, 2- (o-benzoyloxime) -1- [4- (phenylthio) phenyl] -1,2-octanedione and the like.

The additive may be an ionic liquid, a lewis acid, a leveling agent, a silane coupling agent or the like in an amount of 0.01 to 5 wt% based on the total weight of the reactive electrolytic solution composition.

The ionic liquid is a salt composed of a cation and an anion which can exist as a liquid even in a wide temperature range including room temperature. And the ionic liquid has very low vapor pressure and is almost free of volatility. Such an ionic liquid can improve the ionic conductivity and storage stability of the reactive electrolytic solution composition and improve the thermal stability of the electrochromic device.

The ionic liquid includes a dialkyl imidazolium ion or a tetraalkylammonium ion as a cation and an anion such as ClO ₄ ^- , N (SO ₂ CF ₃ ) ₂ ^- , BF ₄ ^- , PF ₆ ^-, and SO ₃ CF ₃ ^- . The alkyl may be an alkyl group having 1 to 10 carbon atoms.

The Lewis acid is a compound capable of receiving an electron pair and is a compound containing any one or more atoms of group 3 to group 13 atoms. Any one or more atoms of Group 3 to Group 13 atoms are not completely filled with the outermost electron structure and thus can receive additional electron pairs. The use of such Lewis acid can significantly increase the dissociation degree of the salts present in the reactive electrolytic solution, thereby providing a reactive electrolytic solution having a very high ionic conductivity.

For example, the Lewis acid may be a halide or a nitrate of boron, or a mixture thereof, and the like. Specific examples of the Lewis acid include boron trifluoride (BF ₃ ), boron chloride (BCl ₃ ), boron bromide (BBr ₃ ), boroniodide (BI ₃ ) It is not. Since the halide or nitrate of boron does not form a metal complex with other components of the reactive electrolytic solution, the ionic conductivity can be improved without affecting the overall performance of the reactive electrolytic solution.

The leveling agent may be added to the reactive electrolytic solution to uniformly apply the reactive electrolytic solution to the porous polymer membrane as a material that improves the coating property.

The leveling agent may be a polyether-modified dialkylpolysiloxane, a polyester-modified dialkylpolysiloxane, or a mixture thereof, but is not limited thereto.

The silane coupling agent may be further included as an adhesive performance improving agent in order to improve the adhesive strength and interface stability of the gel polymer electrolyte and the electrochromic device to the electrochromic material or the electrode.

Any silane coupling agent known in the art may be used without limitation. For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl tri An epoxy group-containing silane coupling agent such as methoxysilane; Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) Containing silane coupling agents such as methoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane and 3-triethoxysilyl-N- (1,3-dimethylbutylidene) ; (Meth) acrylic group-containing silane coupling agents such as 3- (meth) acryloxypropyltrimethoxysilane and 3- (meth) acryloxypropyltriethoxysilane; A silane coupling agent containing an isocyanate group such as 3-isocyanatepropyltrimethoxysilane or 3-isocyanatepropyltriethoxysilane, but is not limited thereto.

The reactive electrolytic solution composition may further include other additives that may be contained in the electrolyte for the electrochromic device, in addition to the components described above.

The present invention provides a method of manufacturing a thin film solar cell, comprising: laminating a porous polymer membrane on a reduced color shift layer;

Applying a reactive electrolytic solution on the porous polymer membrane;

Laminating an oxidative discoloration layer on the electrolyte layer including the porous polymer membrane coated with the reactive electrolytic solution;

And a method for producing the electrochromic device.

The reducing or discoloring layer of the present invention may be formed by forming a transparent electrode serving as a current collector on a transparent substrate and then depositing a reducing coloring material or an oxidative coloring material.

The transparent substrate and the transparent electrode are not particularly limited as long as they are well known in the art. As the transparent substrate, glass, quartz, transparent polymer (polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyimide, polycarbornate, polystylene, polyoxymethylene, triacetyl cellulose) can be used. doped tin oxide (ATO), fluorine doped tin oxide (FTO), indium doped zinc oxide (IZO), and zinc oxide (ZnO). The transparent electrode may be formed on the transparent substrate by a known method such as sputtering, electron beam evaporation, chemical vapor deposition, or sol-gel coating.

The reducing coloring material may be tungsten oxide (WO ₃ ), molybdenum oxide (MoO ₃ ), niobium oxide (Nb ₂ O ₅ ), titanium oxide (TiO ₂ ), or tantalum oxide (Ta ₂ O ₅ ) , But is not limited thereto.

Oxidation color change material is a nickel oxide (NiO), lithium oxide nickel (LiNiO or LiNiO _2), oxidation come Stadium (IrO _3), chromium oxide (CrO _3), manganese oxide (MnO _2), iron oxide (Fe0 _2), cobalt oxide (CoO ₂ ) or oxidized rhodium (RhO ₂ ), but is not limited thereto.

The method of depositing the coloring material on the transparent electrode is not particularly limited as long as it is a method capable of forming a thin film at a constant height from the base surface, and examples thereof include a vacuum deposition method such as sputtering.

As an example of the electrochromic material, WO ₃ is a substance that is colored by a reduction reaction, and the electrochemical mechanism in which electrochromism occurs in an electrochromic device containing such an inorganic metal oxide is explained as shown in Scheme 1. Specifically, when an electric field is applied to the electrochromic device, the proton (H ⁺ ) or lithium ion (Li ⁺ ) contained in the electrolyte is inserted or eliminated as an electrochromic material depending on the polarity of the electric current. The change in the oxidation number of the transition metal contained in the electrochromic material changes the optical characteristic and transmittance (color) of the discolored material itself.

[Reaction Scheme 1]

WO ₃ (transparent) + xe ^- + _x M ⁺ ↔ M _x WO ₃ (deep blue)

(M is a proton or an alkali metal cation such as Li ⁺ ).

That is, when an electrical signal is applied from the outside to the transparent electrode, ions of the electrolyte layer migrate to the reduced color changing layer, and the reduced color changing layer becomes a reduced state and the color changes.

Further, unlike the reduction coloring layer, the oxidizing coloring layer moves the ions to the electrolyte layer to become an oxidized state and change color.

On the other hand, in order to return from the discolored state to the transparent state, the reducing color-changing layer becomes the oxidized state and the oxidative discolored layer becomes the reduced state.

The porous polymer film thus formed may be laminated on the reduced color shift layer and the reactive electrolytic solution may be coated on the reduced color layer. The reactive electrolytic solution may be prepared by a conventional method known in the art. For example, , Spray coating, gravure coating, doctor blade coating, and the like.

The present invention may include a step of laminating an oxidative discoloration layer on an electrolyte layer including a porous polymer membrane impregnated in a reactive electrolytic solution deposited on the reduced color discoloration layer.

Further, the present invention may include a step of irradiating the stacked electrochromic device with light to gel-polymerize the electrolyte layer.

The light irradiation is not particularly limited, but ultraviolet light (UV) is preferable. Also, the light irradiation time is not particularly limited, and if it is irradiated for 1 to 10 minutes, the crosslinking agent is preferably cured in an IPN (interpenetrating polymer networks) structure.

Further, the present invention may further include the step of adhering to the both sides of one side of each of the laminated electrochromic devices with an adhesive such as silicon and a sealing agent.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

[Example 1]

(Preparation of porous polymer membrane)

1 g of polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) (Kynar 2801) and 1 g of DBP (dibutylphthalate) were extracted and stirred for 8 hours with 8 g of Acetone to dissolve the PVDF-HFP and DBP .

The solution was cast on a glass plate using a doctor blade, and then dried at 25 DEG C for 30 minutes to form a film. The thickness of the polymer film formed when the height of the doctor blade was 300 mu m was measured to be 20 mu m.

The formed film was impregnated with methanol to dissolve DBP, and the resultant was dried at room temperature for 1 hour to prepare pore-forming opaque porous polymer membranes.

(Production of electrochromic device)

10.68 g (corresponding to 0.1 mol) of LiClO ₄ lithium salt is dissolved in an organic solvent PC (propylene carbonate) using a 100 ml volumetric flask to prepare a 1 M concentration liquid electrolyte. ₄ g of a 1 M LiClO ₄ in PC electrolyte thus prepared was mixed with 6 g of a crosslinking agent PEGDA (polyethylene glycol diacrylate), 0.6 g of a photoinitiator DMPAP (2,2-dimethoxy-2-phenylacetophenone), 0.1 g of boron fluoride as a Lewis acid, 0.1 g of 1-butyl-3-methylimidazolium-ClO ₄ ^- , a polyether-modified dialkylpolysiloxane as a leveling agent, 0.02 g of a polyether-modified dialkylpolysiloxane, And 0.1 g of propyl methyldiethoxysilane were stirred for 2 hours to prepare a reactive electrolytic solution.

A 1 cm imide tape was attached to two ITO coated glass and WO ₃ and NiO were respectively deposited by DC sputtering. WO ₃ deposition was deposited at a film thickness of 300 nm for 20 minutes at 500 W and 10 rpm under the condition of Ar: O ₂ gas at 70:30, and NiO The deposition was carried out under the condition of Ar: O ₂ gas at 90:10, 200 W, 10 rpm for 25 minutes at 100 nm.

On the electrode substrate on which WO ₃ was deposited in a glove box in an Ar atmosphere, the porous polymer membrane having the same area as above prepared was placed, and then the prepared reactive electrolytic solution was applied. It was confirmed that the opaque porous polymer membrane was transparently adhered by the application and that the impregnation was sufficient. And an electrode substrate on which NiO was deposited was laminated thereon. The electrochromic device including the polymer electrolyte layer in gel form was prepared by irradiating the stacked electrochromic device with UV light of 365 nm for 5 minutes by UV lamp to crosslink PEGDA. The characteristics of the prepared electrochromic device were evaluated, and the results are shown in Table 1 below.

[Example 2]

10.68 g (corresponding to 0.1 mol) of LiClO ₄ lithium salt is dissolved in an organic solvent PC (propylene carbonate) using a 100 ml volumetric flask to prepare a 1 M concentration liquid electrolyte. 5 g of a 1 M LiClO ₄ in PC electrolyte thus prepared, 5 g of a crosslinking agent PEGDA (polyethylene glycol diacrylate), 0.6 g of a photoinitiator DMPAP (2,2-dimethoxy-2-phenylacetophenone), 0.1 g of boron fluoride as a Lewis acid, 0.1 g of 1-butyl-3-methylimidazolium-ClO ₄ ^- , a polyether-modified dialkylpolysiloxane as a leveling agent, 0.02 g of a polyether-modified dialkylpolysiloxane, And 0.1 g of propyl methyldiethoxysilane were stirred for 2 hours to prepare a reactive electrolytic solution, thereby preparing an electrochromic device. The characteristics of the prepared electrochromic device were evaluated, and the results are shown in Table 1 below.

[Example 3]

10.68 g (corresponding to 0.1 mol) of LiClO ₄ lithium salt is dissolved in an organic solvent PC (propylene carbonate) using a 100 ml volumetric flask to prepare a 1 M concentration liquid electrolyte. 6 g of 1 M LiClO ₄ in PC electrolyte thus prepared was mixed with ₄ g of crosslinking agent PEGDA (polyethylene glycol diacrylate), 0.6 g of photoinitiator DMPAP (2,2-dimethoxy-2-phenylacetophenone), 0.1 g of boron fluoride, 0.1 g of 1-butyl-3-methylimidazolium-ClO ₄ ^- , a polyether-modified dialkylpolysiloxane as a leveling agent, 0.02 g of a polyether-modified dialkylpolysiloxane, And 0.1 g of propyl methyldiethoxysilane were stirred for 2 hours to prepare a reactive electrolytic solution, thereby preparing an electrochromic device. The characteristics of the prepared electrochromic device were evaluated, and the results are shown in Table 1 below.

[Assessment Methods]

1. CV (cyclic voltammetry)

In order to observe the electrochemical characteristics of the thus-prepared electrochromic device of Example 2, oxidation / reduction characteristics were observed using cyclic voltammetry (CV). The voltage was set in the range of 2 to 2.5 V and the scan rate was measured at 100 mV or more at 50 mV. The results are shown in Fig.

2. Observation of permeability

The electrochromic device of Example 2 was subjected to a coloring and decoloring reaction by applying a DC voltage (switching for 2 minutes at -2 V and 100 times for 2 minutes at 2 minutes), and the electrochromic characteristics at that time were measured . The electrochromic properties of the device were measured by using a transmittance measuring device (Avantes, Netherlands). The transmittance of 550 nm was measured in visible region, which is most sensitive to visible light. The results are shown in Fig.

3. Ion conductivity measurement

Bulk resistance (R _b ) was measured to observe the ionic conductivity change of the electrochromic device. AC impedance method, and the ion conductivity was calculated through the equation (2).

[Reaction Scheme 2]

(t is the thickness of the polymer electrolyte, and A is the area of the polymer electrolyte).

The above A was 2 cm ² , and t, R _b , and ionic conductivity are shown in Table 1 below.

PEGDA content (wt%) Electrolyte Thickness (㎛) Bulk Resistance (Ω) Ionic Conductivity (S · cm ^-1 ) Example 1 40 214 22.62 4.70x10 ^-4 Example 2 50 349 152.0 1.14 x 10 ^-4 Example 3 60 457 878.9 0.26x10 ^-4

From the above experimental results, the electrochromic device of the present invention showed excellent lifetime characteristics at room temperature.

As shown in FIG. 4, it was confirmed that the room temperature lifetime characteristics were remarkably improved even in the case of Example 2 containing about 50 wt% of the crosslinking agent. When the content of the cross-linking agent is less than 50% of the liquid electrolyte, the electrochromic characteristics are similar or superior to those of the conventional gel polymer electrolyte system, and a stable electrochromic device is formed and the lifetime characteristics can be effectively improved Able to know.

In addition, the electrochromic device manufactured as shown in FIG. 5 had a transmittance of 80% or more at 550 nm after 100 passes after the initial driving. This shows that even if the electrochromic device of the present invention is driven several times, the color is stably maintained and uniform color change and excellent durability are obtained.

Also, in Examples 1 to 3 of Table 1, the ionic conductivity tends to decrease as the content of the crosslinking agent increases. It was found that the higher the crosslinking agent content, the higher the degree of crosslinking of the gel-type polymer electrolyte and the lower the ionic conductivity, and the Example 1 of the present invention showed an excellent ionic conductivity with an optimal content.

Therefore, the electrochromic device of the present invention can increase uniform discoloration and durability, ensure long-term stability, obtain excellent ion conduction velocity, and can be used for all industries in which electrochromic devices such as large-sized smart windows are applied .

Claims (17)

An electrochromic device comprising a reducing color change layer, an electrolyte layer, and an oxidative color change layer,
Laminating a porous polymer membrane on the reduction discoloration layer;
Applying a reactive electrolytic solution on the porous polymer membrane;
Laminating an oxidative discoloration layer on the electrolyte layer including the porous polymer membrane coated with the reactive electrolytic solution; And
Irradiating the stacked electrochromic device with light to polymerize the electrolyte layer into a gel;
Wherein the electrochromic device further comprises an electrochromic device. The method according to claim 1,
The porous polymer membrane may be formed of at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA) Wherein the electrochromic device is at least one selected from the group consisting of nitrile (PAN), polyethylene (PE), and polypropylene (PP). The method according to claim 1,
Wherein the reactive electrolytic solution comprises an electrolyte salt, an organic solvent, a crosslinking agent, a photoinitiator, and an additive. The method of claim 3,
Wherein the reactive electrolytic solution contains 35 to 70% by weight of an electrolyte salt dissolved in an organic solvent, 25 to 60% by weight of a crosslinking agent, 0.1 to 5% by weight of a photoinitiator and 0.01 to 5% by weight of an additive. The method of claim 3,
Wherein the additive is at least one selected from an ionic liquid, a Lewis acid, a leveling agent, a silane coupling agent, or a mixture thereof. The method of claim 3,
The electrolyte salts are LiF, LiCl, LiBr, LiI, LiClO 4, LiClO 3, LiAsF 6, LiSbF 6, LiAl0 4, LiAlCl 4, LiNO 3, LiN (CN) 2, LiPF 6, Li (CF 3) 2 PF 4 _{, Li (CF 3) 3 PF} 3, Li (CF 3) 4 _{PF 2, Li (CF 3)} 5 PF, Li (CF 3) 6 P, LiSO 3 CF 3, LiSO 3 C 4 F 9, LiSO 3 (CF 2) 7 CF 3, LiN (SO 2 CF 3) 2, _{LiOC (CF 3) 2 CF 2} CF 3, LiCO 2 CF 3, LiCO 2 CH 3, LiSCN, LiB (C 2 O 4) 2, LiBF 2 (C 2 O 4) , and one selected from the group consisting of LiBF ₄ By weight based on the total weight of the electrochromic device. The method of claim 3,
The organic solvent may be selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, methylethyl carbonate, At least one member selected from the group consisting of ethyl fluoroethyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, and butylenes carbonate, and at least one member selected from the group consisting of methyl ethyl ketone, methyl ethyl ketone, methyl ethyl ketone, Wherein the electrochromic device is a mixture. The method of claim 3,
The crosslinking agent is selected from the group consisting of ethylene glycol di (meth) acrylate, poly (ethylene glycol) di (meth) acrylate 1,6-hexanediol di (meth) acrylate, tri (propylene glycol) di (Meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate. . 4. The method of claim 3,
Wherein the photoinitiator is at least one selected from an acetophenone-based compound, a benzophenone-based compound, a thioxanthone-based compound, a benzoin-based compound, a triazine-based compound, and an oxime-based compound. The method of claim 5, wherein
The ionic liquid includes a dialkyl imidazolium ion or a tetraalkylammonium ion as a cation and an anion such as ClO ₄ ^- , N (SO ₂ CF ₃ ) ₂ ^- , BF ₄ ^- , PF ₆ ^-, and SO ₃ CF ₃ ^- . The method of claim 5,
The Lewis acid is hydrofluoric boron (BF _3), boron chloride (BCl _3), bromide boron (BBr _3), iodine boron (BI ₃₎ or the method of an electrochromic device at least one selected from a mixture thereof. The method of claim 5,
Wherein the leveling agent is at least one selected from a polyether-modified dialkyl polysiloxane, a polyester-modified dialkyl polysiloxane, or a mixture thereof. The method of claim 5,
The silane coupling agent may be at least one selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3- glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, 3-aminopropyltrimethoxysilane, N- One selected from the group consisting of - (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, By weight based on the total weight of the electrochromic device. The method according to claim 1,
The reducing color change layer may be formed by forming a transparent electrode on a transparent substrate, and then forming a transparent electrode by depositing tungsten oxide (WO ₃ ), molybdenum oxide (MoO ₃ ), niobium oxide (Nb ₂ O ₅ ), titanium oxide (TiO ₂ ) Or a tantalum oxide (Ta ₂ O ₅ ) film. The method according to claim 1,
The oxidation color change layer after forming the transparent electrode on a transparent substrate, a nickel oxide (NiO), lithium oxide nickel (LiNiO), oxidation come Stadium (IrO _3), chromium oxide (CrO _3), manganese oxide (MnO ₂₎ , Iron oxide (FeO ₂ ), cobalt oxide (CoO ₂ ), or oxidized rhodium (RhO ₂ ). An electrochromic device produced by the method of any one of claims 1 to 15. A smart window comprising the electrochromic device of claim 16.

Images