KR20170101702A

KR20170101702A - Electrochromic device

Info

Publication number: KR20170101702A
Application number: KR1020160024593A
Authority: KR
Inventors: 김용찬; 김기환; 김수진
Original assignee: 주식회사 엘지화학
Priority date: 2016-02-29
Filing date: 2016-02-29
Publication date: 2017-09-06
Also published as: KR102010733B1

Abstract

The present invention relates to an electrochromic element with improved electrochromic speed and durability, and a manufacturing method thereof. The electrochromic element can be usefully used in various devices such as a smart window, a smart mirror, a display, an electronic paper, and an adaptive camouflage. The electrochromic element sequentially comprises a first substrate, a first electrode layer, an electrochromic layer, an electrolyte layer, an ion storage layer, and a second electrode layer.

Description

[0001] Electrochromic device [0002]

The present application relates to an electrochromic device and its use.

Electrochromism is a phenomenon in which optical properties such as color or transmittance of an electrochromic material are changed by electrochemical oxidation and reduction reactions. When an external voltage is applied to an electrochromic material, the optical properties of the material, for example, the inherent color and transmittance of the material, are reversibly changed by the movement of electrons, oxidation, and reduction reactions.

The electrochromic device can be composed of a working electrode, a counter electrode and an electrolyte in a structure like a battery. As the electrochromic material, for example, an inorganic electrochromic material such as a metal oxide may be used. The inorganic electrochromic material may be formed in the form of a film on a transparent conductive electrode, for example, an ITO or FTO glass so that its characteristics can be observed and devices can be constituted. For example, ions such as Li ⁺ or Na ⁺ migrate, and at the same time electrons move through an external circuit, thereby altering the electron density of the electrochromic material and thereby changing its optical properties. That is, when electrons and ions are inserted and extracted by an electrochemical oxidation or reduction reaction, coloration or discoloration occurs on the surface of the metal oxide.

Electrochromic devices can be manufactured in a wide range of devices with low cost and have low power consumption, so they can be used in various fields such as smart windows, smart mirrors, and electronic paper. However, the electrochromic device has a disadvantage in that the rate of discoloration is slow, and this disadvantage can be a limitation especially in the large-sized electrochromic device. Various attempts have been made to lower the surface resistance of a transparent conductive electrode serving as a current collector of an electrochromic device in order to overcome such disadvantages.

Patent Document 1: Korean Patent Laid-Open Publication No. 2008-0051280

An object of the present invention is to provide an electrochromic device having excellent electrochromic rate and durability and its use.

The present application relates to an electrochromic device. The electrochromic device of the present application may include a first substrate, a first electrode layer, an electrochromic layer, an electrolyte layer, an ion storage layer, a second electrode layer, and a second substrate sequentially. In this application, at least one electrode layer of the first electrode layer and the second electrode layer may be a composite electrode layer including a first metal oxide layer, a metal layer and a second oxide layer sequentially. The electrochromic device of the present application may include a conductive barrier layer on one side of the second metal oxide layer. Such an electrochromic device can have excellent electrochromic rate and durability.

Fig. 1 exemplarily shows an electrochromic device according to one embodiment of the present application. FIG. 1 exemplarily shows a case where the first electrode layer is a composite electrode layer. The electrochromic device shown in Fig. 1 includes a first substrate 10, a first electrode layer 11, an electrochromic layer 12, an electrolyte layer 20, an ion storage layer 32, a second electrode layer 31 The first electrode layer 11 includes a first metal oxide layer 11a, a metal layer 11b and a second metal oxide layer 11c in sequence And a conductive barrier layer 40 on one side of the second metal oxide layer 103.

Hereinafter, the electrochromic device of the present application will be specifically described.

[Board]

The electrochromic device may include first and second substrates. The electrochromic device may include the first and second substrates in an opposed arrangement, and a first electrode layer, an electrochromic layer, an electrolyte layer, an ion storage layer, and a first electrode layer may be interposed between the first substrate and the second substrate. Two electrode layers may be sequentially provided.

The first and second substrates may each be a glass substrate or a polymer substrate. Specifically, the first and second substrates may be any one selected from the group consisting of glass, glass fiber, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyether sulfone, polyimide, and combinations thereof. According to one embodiment of the present application, the first substrate may be a glass substrate and the second substrate may be a polymer substrate. When the second substrate is a polymer substrate, the thickness can be appropriately selected in consideration of the object of the present application. The thickness of the polymer substrate may be, for example, 10 μm to 300 μm, more specifically 150 μm to 250 μm.

[Electrode layer]

The electrochromic device may include a first electrode layer and a second electrode layer. The first electrode layer may be formed on the first substrate, and the second electrode layer may be formed on the second substrate. The electrochromic device may include the first electrode layer and the second electrode layer in an opposed arrangement, and the electrochromic layer, the electrolyte layer, and the ion storage layer are sequentially disposed between the first electrode layer and the second electrode layer, Lt; / RTI >

The first and second electrode layers may function to supply electric charge to the electrochromic layer or the ion storage layer. The first electrode layer may be referred to as an electrode adjacent to the electrochromic layer and having an electrochromic action in the electrochromic device, for example, an active electrode. The second electrode layer may be referred to as an electrode, for example, a counter electrode, which is adjacent to the ion storage layer and can accommodate hydrogen or lithium ions, etc., which have been desorbed from the active electrode. However, when the ion storage layer includes an electrochromic material as described later, both the first electrode layer and the second electrode layer may function as counter electrodes while being active electrodes.

At least one electrode layer of the first electrode layer and the second electrode layer may be a composite electrode layer including a first metal oxide layer, a metal layer, and a second oxide layer sequentially. Either the first electrode layer or the second electrode layer may be a composite electrode layer, or both the first electrode layer and the second electrode layer may be a composite electrode layer. The first metal oxide layer may be adjacent to the first and / or second substrate relative to the second metal oxide layer. Such a composite electrode layer can realize a high visible light transmittance and a low surface resistance when the optical constant is appropriately adjusted.

The composite electrode layer may have an average visible light transmittance of 80% or more. In this specification, visible light may mean light having a wavelength of about 380 nm to 700 mm. Since such composite electrode layer can exhibit excellent transparency, it can be substituted for the transparent conductive oxide, which is a material of the conventional electrode layer, and can be suitable for the implementation of an electrochromic device.

The composite electrode layer may have a surface resistance of 10? / Sq or less. Since such a composite electrode layer has a low surface resistance value, it is possible to provide an electrochromic device having an improved electrochromic rate. Specifically, the coloring and discoloration conversion time of the electrochromic device can be reduced.

The composite electrode layer having the visible light transmittance and the surface resistance can be implemented by organically controlling the refractive indexes and thicknesses of the first metal oxide layer, the metal layer, and the second oxide layer.

The refractive index of the first metal oxide layer to light at a wavelength of 550 nm may be, for example, from 1.8 to 2.8, more specifically from 2.0 to 2.5. Or the refractive index of the first metal oxide layer with respect to light having a wavelength of 370 nm may be 2.0 to 3.2. The thickness of the first metal oxide layer may be, for example, 20 nm to 60 nm, more specifically, 20 nm to 50 nm, 20 nm to 40 nm. The first metal oxide layer may be made of a suitable material to exhibit the refractive index in the thickness range. For example, the first metal oxide layer may include niobium (Nb) oxide, cerium (Ce) oxide, or indium doped tin oxide (ITO).

The refractive index of the metal layer with respect to light at a wavelength of 550 nm may be, for example, less than 0.5, more specifically, less than 0.4, less than 0.3, or less than 0.2. The thickness of the metal layer may be, for example, 5 nm to 20 nm, more specifically 10 nm to 15 nm. The metal layer may be made of a suitable material to exhibit the refractive index in the thickness range. For example, the metal layer may comprise an alloy of silver (Ag) or silver (Ag). The alloy metal with silver may be, for example, copper (Cu), palladium (Pd), nickel (Ni) or zinc (Zn)

The refractive index of the second metal oxide layer with respect to light having a wavelength of 550 nm may be, for example, 1.5 to 2.5, more specifically 1.7 to 2.3 to 1.9 to 2.1. The thickness of the second metal oxide layer may be, for example, 20 nm to 80 nm more specifically 30 nm to 70 nm or 40 nm to 60 nm. The second metal oxide layer may be made of a suitable material to exhibit the refractive index in the thickness range. For example, the bimetal oxide layer may be formed of a material selected from the group consisting of Aluminum-doped Zinc Oxide (AZO), Galium-doped Zinc Oxide (GZO), Indium-doped Tin Oxide (ITO) .

In the composite electrode layer, the refractive index of the first metal oxide layer may be higher than that of the second metal oxide layer, and the refractive index of the metal layer may be lower than that of the second metal oxide layer. In view of such a refractive index relationship, it may be more advantageous to realize excellent visible light transmittance and low sheet resistance.

The composite electrode layer may be formed through a thin film deposition process. Examples of the thin film deposition process include, but are not limited to, a vacuum deposition process such as sputtering.

If only one of the first electrode layer and the second electrode layer is a composite electrode layer, the other electrode layer may be a single-layer electrode layer including a conductive material. In one example, the first electrode layer may be a composite electrode layer and the second electrode layer may be a single layer electrode layer comprising a conductive material.

As the conductive material, for example, a transparent conductive oxide (TCO), a conductive polymer, a silver nano wire, or a metal mesh may be exemplified. Examples of the transparent conductive oxide include ITO (indium tin oxide), FTO (fluorinated tin oxide), AZO (aluminum doped zinc oxide), GZO (gallium doped zinc oxide), ATO (antimony doped tin oxide), IZO doped Zinc Oxide (ITO), Niobium-doped Titanium Oxide (NTO), ZnO, or CTO, but the present invention is not limited thereto. Such an electrode layer can be produced by forming a conductive material on a substrate in a thin film form through a process such as sputtering or digital printing.

When the second electrode layer is a single layer electrode layer, the thickness can be appropriately selected in consideration of the object of the present application. The thickness of the single layer electrode layer may be, for example, 100 nm to 3000 nm, more specifically 150 nm to 250 nm.

The voltage applied to the first electrode layer and the second electrode layer through the external circuit can be appropriately adjusted within a range that does not impair the purpose of the present application. The higher the voltage applied, the better the characteristics of the electrochromic device, but the degradation of the device may be degraded by accelerating the deterioration of the device. In consideration of this point, the external voltage applied to the first electrode layer and the second electrode layer can be appropriately adjusted. For example, the voltage applied to the first or second electrode layer through the external circuit may be -5 V to +5 V, more specifically, -2 V to +2 V, but is not limited thereto. In addition, the voltages at the time of coloring and decoloring may be the same or different, and may be suitably adjusted as needed. The voltage may be applied by an alternating current (AC) power source, and the power source for applying the voltage or the method thereof may be appropriately selected by a person skilled in the art.

[Conductive barrier layer]

The electrochromic device may comprise a conductive barrier layer provided on one side of the second metal oxide layer. When the first electrode layer is a composite electrode layer, a conductive barrier layer may be provided between the second metal oxide layer and the electrochromic layer. When the second electrode layer is a composite electrode layer, a conductive barrier layer may be provided between the second metal oxide layer and the ion storage layer.

The electrochromic device of the present application can ensure excellent durability through the conductive barrier layer. Specifically, when the electrolyte layer is driven to a specific potential or higher, ionization can proceed to the metal of the composite electrode layer due to penetration of ions included in the ion storage layer and the electrolyte layer, for example, lithium ions. In this case, There is a problem that the etching deteriorates. According to the present invention, it is possible to prevent penetration of ions by providing a conductive barrier layer between the composite electrode layer and the electrolyte layer, thereby preventing deterioration of the composite electrode layer even within a specific reaction potential, thereby improving the durability of the electrochromic device .

The thickness of the conductive barrier layer can be appropriately selected in consideration of the object of the present application. The thickness of the conductive barrier layer may be, for example, 100 nm to 500 nm, more specifically 200 nm to 300 nm. The conductive barrier layer may comprise a conductive material. As the conductive material, for example, a transparent conductive oxide (TCO) can be exemplified. Examples of the transparent conductive oxide include indium doped tin oxide (ITO), fluoro-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), gallium zinc oxide (GZO) (HTO), indium-doped zinc oxide (IZO), niobium-doped titanium oxide (NTO), cadmium-doped titanium oxide (CTO), Cadmium doped Zinc Oxide, or Zinc Oxide. However, the present invention is not limited thereto.

[Electrochromic layer]

The electrochromic layer may comprise an electrochromic material. Electrochromism is a reversible change in color depending on the electrical signal. Electrochromism can be caused by the insertion and extraction of electrons and ions (H ⁺ , Li ^+, etc.) into the electrochromic material. Electrochromic materials can be classified as reductive electrochromic materials that are reversibly colored by ion implantation and oxidative electrochromic materials that are reversibly colored by ion extraction.

The electrochromic material may be a metal oxide electrochromic material, a metal complex, an organic electrochromic material, or a conductive polymer electrochromic material.

Examples of the metal oxide electrochromic material include tungsten (W), titanium (Ti), vanadium (V), molybdenum (Mo), niobium (Nb), chromium (Cr), manganese (Mn) , Iron (Fe), nickel (Ni), cobalt (Co), iridium (Ir) and lithium nickel (LiNi). Metal oxides such as tungsten (W), titanium (Ti), vanadium (V), molybdenum (Mo), and niobium (Nb) can be classified as reducing electrochromic materials, and vanadium (V) Manganese (Mn), tantalum (Ta), iron (Fe), nickel (Ni), cobalt (Co), iridium (Ir) or lithium nickel (LiNi)

As the metal complex, for example, Prussian blue, phthalocyanines or bismuth may be used.

As the organic electrochromic material, for example, viologen or quinone can be used.

Examples of the conductive polymer electrochromic material include polythiophene, polyaniline, polypyrrole, polyanthracene, polyfluorene, polycarbazole, polyphenylene, At least one of polyphenylenevinylene and derivatives thereof may be used.

The thickness of the electrochromic layer can be appropriately selected in consideration of the object of the present application. The thickness of the electrochromic layer may be, for example, 100 nm to 500 nm, more specifically, 200 nm to 400 nm.

[Ion storage layer]

The ion storage layer may serve to accept and discharge ions of the ions necessary for discoloring the electrochromic layer. Accordingly, in order to match the charge balance between the ion storage layer and the electrochromic layer, the ion storage layer may include a conductive material complementary to the electrochromic layer.

The ion storage layer may comprise an oxidative conducting material when the composite electrochromic layer comprises a reduced electrochromic material. Or the ion storage layer may comprise a reducing conductive material when the composite electrochromic layer comprises an oxidative electrochromic material.

As one example, the conductive material included in the ion storage layer may be an electrochromic material. When the composite electrochromic layer contains a reducing electrochromic material, the ion storage layer may include an oxidizing electrochromic material, and when the composite electrochromic layer contains an oxidizing electrochromic material, the ion storage layer may contain a reducing electrochromic material can do. According to one embodiment of the present application, when tungsten oxide (WO ₃ ) is used in the composite electrochromic layer, lithium nickel oxide (LiNiO _x ) can be used in the ion storage layer.

Or the ion storage layer may comprise a suitable conductive material, for example a conductive material such as a conductive graphite, whether the composite electrochromic layer comprises a red coloring material or an oxidative coloring material.

The thickness of the ion storage layer can be suitably selected within a range that does not impair the purpose of the present application. For example, the thickness of the ion storage layer may be from 50 nm to 300 nm, more specifically from 150 nm to 250 nm. When the thickness of the ion storage layer is in the above range, it is possible to provide an electrochromic device improved in electrochromic rate and durability.

[Electrolyte Layer]

The electrolyte layer may comprise an electrolyte salt. Specifically, the electrolyte layer may be any one selected from the group consisting of a liquid electrolyte in which an electrolytic salt is dissolved, a gel electrolyte, a solid electrolyte, a polymer electrolyte and a gel polymer electrolyte. In the case of a liquid electrolyte, an electrolytic salt may be dissolved in a solvent have. According to one embodiment of the present application, the electrolyte may be an gel-like polymer electrolyte.

The electrolyte salt may be an organic electrolyte salt or an inorganic electrolyte salt. Than electrolytic said concretely salt may include lithium salt, potassium salt, sodium salt or ammonium salt such as, for example, electrolyte salt is _{n-Bu 4 NClO 4, n} -Bu 4 NPF 6, NaBF 4, LiClO 4, _{LiPF 6, LiBF 4, LiN (} SO 2 C 2 F 5) 2, LiCF 3 SO 3, C 2 F 6 LiNO 4 S 2, K 4 Fe (CN) 6 and any one of a selected from the group consisting of .

The solvent may be a non-aqueous solvent, and specifically, dichloromethane, chloroform, acetonitrile, ethylene carbonate (EC), propylene carbonate (PC), tetrahydrofuran (THF), butylene carbonate, May be any one selected from the group consisting of

The thickness of the electrolyte layer can be appropriately selected within a range not to impair the purpose of the present application. For example, the thickness of the electrolyte layer may be 50 nm to 300 nm, more specifically 150 nm to 250 nm. When the thickness of the electrolyte layer satisfies the above range, it is possible to provide an electrochromic device improved in electrochromic rate and durability.

The electrochromic device of the present application can be produced by laminating the respective layers described above. The lamination of each layer can be performed by appropriately selecting a known lamination method. For example, the deposition method may be a sputtering method, a sol-gel method, an e-beam evaporation method, a pulsed laser deposition method, a CVD (chemical vapor deposition) method, a spin coating ) Or dip coating may be exemplified.

The electrochromic device of the present application can have excellent electrochromic rate and durability. Such electrochromic devices can be useful for various devices such as smart windows, smart mirrors, displays, electronic paper, and adaptive camouflage. The method of constituting the above apparatus is not particularly limited, and a conventional method can be applied as long as the electrochromic device of the present application is applied.

The present application can provide an electrochromic device having improved electrochromic rate and durability. Such electrochromic devices can be useful for various devices such as smart windows, smart mirrors, displays, electronic paper, and adaptive camouflage.

1 is a schematic diagram of an electrochromic device in one embodiment of the present application.
2 is a schematic diagram of the electrochromic device of Comparative Example 1. Fig.
3 is a schematic diagram of an electrochromic device of Comparative Example 2. Fig.
4 is a time-current graph of Comparative Example 1. Fig.
5 is a time-current graph of Example 1. Fig.
6 is a time-current graph of Comparative Example 2. Fig.
7 is a schematic view of an element of Reference Example 1. [Fig.
FIG. 8 shows the XPS Depth Profile analysis result when depositing the LiNiOx layer.
FIG. 9 shows the XPS Depth Profile analysis result when the LiNiOx layer is colored.
10 shows the XPS Depth Profile analysis result of the decolorization of the LiNiOx layer.

Hereinafter, the contents of the present application will be described in more detail by way of examples and comparative examples, but the scope of the present application is not limited to the following contents.

Example One

WO ₃ Manufacture of electrodes

A niobium oxide (NbOx) layer (thickness: about 30 nm), a silver (Ag) layer (thickness: about 12 nm) and an aluminum oxide (AZO) layer (thickness: about 50 nm) Were sequentially deposited to fabricate a composite electrode layer. Next, an indium tin oxide (ITO) layer (thickness: about 300 nm) was deposited as a conductive barrier layer on a zinc aluminum oxide (AZO) layer using a DC sputter. Next, a working electrode was prepared by depositing a tungsten oxide (WO ₃ ) layer (thickness: about 230 nm) as an electrochromic layer on the indium tin oxide layer using a DC sputtering method.

LiNiOx Manufacture of electrodes

An ITO layer (thickness: about 200 nm) was deposited as an electrode layer on a PET film (thickness: about 188 탆) using a DC sputtering method. A DC sputtering was performed on the ITO layer to deposit nickel lithium oxide LiNiOx) layer (thickness: about 200 nm) was deposited thereon to prepare a counter electrode.

Manufacture of electrochromic devices

PC (propylene carbonate) and LiClO ₄ , A working electrode and a counter electrode were adhered to each other so that the ITO layer of the WO ₃ electrode and the LiNiO x layer of the LiNiO x electrode were in contact with the gel polymer electrolyte to prepare an electrochromic device. 1 is a schematic diagram of an electrochromic device according to Example 1. Fig.

Comparative Example One

In the same manner as in Example 1 except that an ITO layer (thickness: about 200 nm) was deposited instead of the composite electrode layer and the conductive barrier layer in the preparation of the WO ₃ electrode in Example 1, Device. 2 is a schematic diagram of an electrochromic device according to Comparative Example 1. Fig.

Comparative Example 2

The electrochromic device was prepared in the same manner as in Example 1, except that the conductive barrier layer (ITO layer) was not deposited in the preparation of the WO ₃ electrode in Example 1. 3 is a schematic diagram of an electrochromic device according to Comparative Example 2. Fig.

Electrochemical Characterization of Electrochromic Devices 1

The electrochemical characteristics of Example 1 and Comparative Example 1 were evaluated by Potenti-step chronoamperometry (PSCA) using Potentiostat. The electrolyte was prepared by dissolving 1 mole of LiClO ₄ in propylene carbonate (PC) solvent. The working electrode was the WO ₃ electrode of Example 1 and Comparative Example 1, the Pt electrode was used as the counter electrode, and the Ag wire was used as the reference electrode. The specimen size of the working electrode was prepared as 2 cm × 3 cm.

In the PSCA method, a certain voltage is applied in one direction at a constant speed, and then the direction is changed repeatedly. At this time, the current corresponding to the voltage applied to the working electrode is measured. When an external potential is applied, an electrolytic current flows, which decreases with time and becomes zero after a long time. The PSCA method measures the current-time obtained by this potential step. The PSCA of the WO3 electrode was measured by repeating 100 times between -1.0V and 1.0V at a recoding step of 1 sec. FIGS. 4 and 5 are time-current graphs of the WO ₃ electrodes of Comparative Example 1 and Example 1 measured by the PSCA method, respectively. Based on the graph, the coloring and decoloring peak currents and charge amounts are calculated. The evaluation of the electrochromic characteristics proceeds in a constant voltage mode. As shown in FIG. 4 and FIG. 5, a graph is formed in which a momentary amount of current flows instantaneously when a constant potential is applied, and then a maximum value is plotted and decreased. The peak current at this time is called the peak current. The coloring and decoloring time was calculated based on the amount of current of 80% relative to the peak current. The peak current is inversely proportional to the sheet resistance of the electrode layer serving as a current collector and tends to increase in proportion to the value of the lithium ion diffusion coefficient of the electrochromic material.

Table 1 below shows the results of measurement of optical properties based on electrochemical reactions of three electrode cells. The surface resistance was measured by a constant voltage (CV) mode method using a Potentiostat. The transmittance was measured using a UV-vis spectrometer (Solidspec 3700) using a visible light average transmittance And the coloring time was measured by using Potentiostat to determine the peak current level of 80%.

- Driving Bias: -2 to +2 V

-Duration Time: 50s (coloring) - 50s (discoloration)

Comparative Example 1
(ITO electrode layer) Example 1
(Composite electrode layer) Sheet resistance (ohm / sq) 15 5 Peak current (mA) 5 7.5 Transmittance (%) in coloring 39 1.7 Transmittance in decolorization (%) 80 60 Transmittance difference (%) 41 43 Coloring time (seconds) 10 6.5

Referring to FIGS. 4 and 5 and Table 1, it can be seen that the peak current is increased in Example 1 as compared with Comparative Example 1, and the coloring time is decreased according to the low surface resistance characteristic.

Electrochemical Characterization of Electrochromic Devices 2

The electrochemical characteristics of Example 1 and Comparative Example 2 were evaluated by potential-step chronoamperometry PSCA using potentiostat. The results are shown in Fig. 5 (Example 1) and Fig. 6 (Comparative Example 2), except that the WO ₃ electrodes of Example 1 and Comparative Example 2 were used as working electrodes, respectively. And the degree of degradation was evaluated.

Referring to FIG. 6, in Comparative Example 2 in which the conductive barrier layer is not provided, the amount of charge decreases after about 10 cycles, and deterioration occurs upon initial activation. Also, in Comparative Example 1, deterioration occurred after 10 cycles even when a voltage of 1.0 V was applied.

In contrast, referring to FIG. 5, in Example 1 in which the conductive barrier layer is provided, activation was completed after 5 cycles, and durability was demonstrated for 10000 seconds without decreasing the amount of charge.

Reference Example One LiNiOx Manufacture of electrodes

A layer of indium tin oxide (ITO) (thickness: about 32 nm), a layer of silver (Ag) (thickness: about 12 nm) and an layer of indium tin oxide (ITO) 40 nm) were sequentially deposited to fabricate a composite electrode layer. Next, a lithium nickel oxide (LiNiOx) layer (thickness: about 100 nm) was deposited on the indium tin oxide (ITO) layer (thickness: about 30 to 40 nm) using DC sputtering to prepare a LiNiOx electrode. 7 is a schematic diagram of a device according to Reference Example 1. [Fig.

Electrochemical Characterization of Electrochromic Devices 3

The electrochemical characteristics of Reference Example 1 were measured with Potentiostat. As a working electrode, Except that a LiNiOx electrode was used. It is colored when applied at -1 V in the direction of lithium nickel oxide (LiNiOx) which is an electrochromic layer, and is discolored when applied at +1 V. 8 to 10 show XPS Depth Profile analysis results of deposition (sample 1), coloring (sample 2) and decolorization (sample 3) of a lithium nickel oxide (LiNiOx) layer.

Referring to FIG. 8 to FIG. 10, the Li content in FIGS. 9 and 10 is reduced compared to FIG. 8, and Li ions contained in the lithium nickel oxide (LiNiOx) layer penetrate into the electrode layer . As shown in the schematic diagram of FIG. 7, when Li ions penetrate into the electrode layer, there is a possibility that Li deposits with the electrons and grows into a dendrite form. It is presumed that the etching of the metal layer occurs due to such a chemical reaction, which causes deterioration and durability deterioration in Comparative Example 2 of Evaluation 2.

10: first substrate
11: first electrode layer
12: Electrochromic layer
20: electrolyte layer
32: ion storage layer
31: second electrode layer
32: second substrate
40: conductive barrier layer
11a: a first metal oxide layer
11b: metal layer
11c: a second metal oxide layer
11 ': ITO electrode layer

Claims

Wherein at least one of the first electrode layer and the second electrode layer includes a first substrate, a first electrode layer, an electrochromic layer, an electrolyte layer, an ion storage layer, a second electrode layer, and a second substrate, Wherein the first metal oxide layer, the first metal oxide layer, the metal layer, and the second oxide layer are sequentially formed on one surface of the second metal oxide layer, and the conductive barrier layer is formed on one surface of the second metal oxide layer.

The method according to claim 1,
Wherein the composite electrode layer has an average transmittance of visible light of 80% or more.

The method according to claim 1,
Wherein the composite electrode layer has a surface resistance of 10? / Sq or less.

The method according to claim 1,
And the first metal oxide layer has a refractive index of 1.8 to 2.8 with respect to light having a wavelength of 550 nm.

The method according to claim 1,
Wherein the thickness of the first metal oxide layer is 20 nm to 40 nm.

The method according to claim 1,
Wherein the first metal oxide layer comprises niobium (Nb) oxide, cerium (Ce) oxide or indium-doped tin oxide (ITO).

The method according to claim 1,
Wherein the metal layer has a refractive index of less than 0.5 with respect to light having a wavelength of 550 nm.

The method according to claim 1,
Wherein the metal layer has a thickness of 5 nm to 20 nm.

The method according to claim 1,
Wherein the metal layer comprises an alloy of silver (Ag) or silver (Ag).

The method according to claim 1,
And the second metal oxide layer has a refractive index of 1.5 to 2.5 with respect to light having a wavelength of 550 nm.

The method according to claim 1,
And the second metal oxide layer has a thickness of 20 nm to 80 nm.

The method according to claim 1,
The second metal oxide layer may include at least one of Aluminum-doped Zinc Oxide (AZO), Galium-doped Zinc Oxide (GZO), Indium-doped Tin Oxide (ITO), or Niobium (Nb) Electrochromic device.

The method according to claim 1,
The refractive index of the first metal oxide layer is higher than that of the second metal oxide layer, and the refractive index of the metal layer is lower than that of the second metal oxide layer.

The method according to claim 1,
Wherein the conductive barrier layer is present between the second metal oxide layer and the electrochromic layer.

The method according to claim 1,
Wherein the thickness of the conductive barrier layer is 100 nm to 500 nm.

The method according to claim 1,
The conductive barrier layer may be formed of indium tin oxide (ITO), fluoro-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide ), Antimony doped tin oxide (ATO), indium doped zinc oxide (IZO), niobium doped titanium oxide (NTO), cadmium doped zinc oxide (CTO) An electrochromic device comprising a zinc oxide.

The method according to claim 1,
Wherein the first electrode layer is a composite electrode layer and the second electrode layer comprises a transparent conductive material.

The method according to claim 1,
The electrochromic layer includes a metal oxide electrochromic material, an organic electrochromic material, or a conductive polymer electrochromic material.

The method according to claim 1,
The electrochromic layer may be formed of a material selected from the group consisting of tungsten (W), titanium (Ti), vanadium (V), molybdenum (Mo), niobium (Nb), chromium (Cr), manganese (Mn), tantalum (Ta) An electrochromic device comprising at least one metal oxide selected from the group consisting of nickel (Ni), cobalt (Co), iridium (Ir) and lithium nickel (LiNi).

The method according to claim 1,
Wherein the ion storage layer comprises an oxidative conductive material when the electrochromic layer contains a reducing electrochromic material or a reducing conductive material when the electrochromic layer contains an oxidative electrochromic material.

The method according to claim 1,
Wherein the electrolyte layer comprises an electrolytic salt.

A smart window comprising the electrochromic device of claim 1.