KR20080051280A - Electrode for electrochromic device and electrochromic device having the same - Google Patents

Abstract

An electrode for an electro-chromic device and an electro-chromic device having the same are provided to increase redox(reduction-oxidation) reaction by enlarging a contact area where an electrode contacts with an electrolytic and to have good chromic property. An electrode for electro-chromic device includes substrates(1,8), first conductive material layers(2,7), second conductive material layers(3,6) which are patterned, and an electro-chromic material layer in order. The second conductive material layers of electrode for the electro-chromic device pile on a portion of the first conductive material layer by a pattern shape to form an unevenness portion. The electro-chromic material layer is piled according to the unevenness portion. The electro-chromic device includes a first electrode, a second electrode and an electrolyte. The first electrode and the second electrode are an oxidation electrode and a reduction electrode.

Description

Electrode for electrochromic device and electrochromic device having the same {ELECTRODE FOR ELECTROCHROMIC DEVICE AND ELECTROCHROMIC DEVICE HAVING THE SAME}

Figure 1 shows a cross-sectional structure of an electrochromic device comprising an electrode described in the present invention.

2 illustrates a linear repeating pattern form as an example of the second conductive material pattern formed on the first conductive material layer.

3 illustrates a lattice type repeating pattern as an example of the second conductive material pattern formed on the first conductive material layer.

4 illustrates an example of a concentric circular pattern as an example of a second conductive material pattern formed on the first conductive material layer.

<Description of Drawing>

DESCRIPTION OF SYMBOLS 1 Base material 2 First conductive material layer 3 Electrochromic material layer

4: second conductive material layer 5: electrolyte

6 layer of electrochromic material of counter electrode 7 layer of first conductive material of counter electrode

8 Base material of counter electrode 9 Encapsulant 10,80 Clip (electrode connection part)

The present invention relates to an electrode and an electrochromic device including the same, which increases the redox reactivity by increasing the contact area between the electrode and the electrolyte and improves the electrical conductivity of the electrode.

The electrochromic device uses a phenomenon in which the light transmittance of the electrochromic material is changed by an electrochemical redox reaction. The electrochromic device is decolorized and colored by reversibly applying voltage to the device, and is used in a room mirror, smart window, display, etc. It can be applied.

Electrochromic materials that can be used in the electrochromic device are inorganic and organic, and representative inorganic materials include WO ₃ , NiO _x , V ₂ O ₅ , LiNiO _x , CeO ₂ -TiO ₂ , and Nb ₂ O ₅ . Among them, WO ₃ and the like are the substances to be colored by the reduction reaction, NiO _x , Nb ₂ O ₅ and the like are the substances to be colored by the oxidation reaction. Accordingly, an electrochromic device using an inorganic color change material is generally configured by pairing a reducing inorganic color change layer used as an active electrode and an oxidative inorganic color change layer used as an ion storage electrode.

The electrochemical mechanism that causes electrochromic in the inorganic electrochromic device can be generally described as follows. When voltage is applied to the electrochromic device, protons (H ⁺ ) or lithium ions (Li ⁺ ) contained in the electrolyte are inserted into or desorbed from the electrochromic material depending on the polarity of the current. In order to change the oxidation number of the transition metal contained in the electrochromic material, the optical properties (ex. Transmittance) of the electrochromic material itself change.

On the other hand, there are some problems to be solved in order to commercialize the electrochromic device using the inorganic electrochromic material. For example, the discoloration reaction time is slow, the light transmittance difference is not large at the time of coloration / discoloration, and when manufacturing a large-area device for application to a smart window, the discoloration disparity occurs between the edges and the center of the device, the discoloration occurs unevenly Etc.

In order to solve the problems of the inorganic electrochromic device as described above, the amount of lithium ions inserted / desorbed into the electrochromic material layer should be higher, the speed of insertion / desorption should be faster, and the electrical conductivity of the electrode will be further improved. There is a need. This requirement may be solved by a new electrochromic material, but also by a method of properly modifying the structure of the device.

For example, if the specific surface area of the electrochromic material layer is increased to increase the contact area with the electrolyte, the amount of insertion / desorption of lithium ions may be increased for a predetermined time, and the insertion / desorption rate may be increased. In some cases, an electrochromic material in the form of a porous thin film is used as a method of increasing the specific surface area of the electrochromic material layer, but various weaknesses may be problematic due to low mechanical strength of the material itself. In addition, there is a method of increasing the specific surface area by forming irregular irregularities by etching the surface of the electrochromic material layer, but in this case, the light transmittance of the electrochromic device may be degraded.

The present inventors can increase the contact area with the electrolyte when the electrochromic material layer in the electrode for the electrochromic device forms irregularities in the form of a pattern, and a second conductivity such as a metal under the electrochromic material layer for forming such a pattern. It has been found that by forming a pattern with the material, the electrical conductivity of the electrode can be further improved.

Conventionally, there has been a technique of increasing the surface area by unevening the substrate itself so that the film thereon is uneven, but in the present invention, by forming a patterned conductive material on the substrate, not only the effect of uneven formation but also electrical conductivity There is an advantage to maximize the electrochemical reaction by increasing.

Accordingly, the present invention provides an electrode including a second conductive material layer stacked in a pattern shape on a portion of a transparent electrode to form an uneven portion, and an electrochromic material layer stacked along the uneven shape thereon, a method of manufacturing the same, and the electrode It is an object to provide an electrochromic device comprising a.

The present invention; A first conductive material layer; A patterned second conductive material layer; And an electrochromic material layer in turn, wherein the second conductive material layer is stacked in a pattern on a portion of the first conductive material layer to form an uneven portion, and the electrochromic material layer is stacked along the uneven shape. It provides an electrode characterized by being.

In addition, the present invention includes the steps of a) laminating a first conductive material layer on a substrate; b) forming an unevenness by stacking a second conductive material layer in a pattern form on a portion of the first conductive material layer; And c) laminating an electrochromic material layer along the concave-convex shape. It provides a method for producing the electrode described above. .

In addition, the present invention provides an electrochromic device having the electrode described above.

Hereinafter, the present invention will be described in detail.

An example in which the electrode of the present invention is used in an electrochromic device is shown in FIG. 1, and the configuration of the present invention will be described with reference to the example of FIG. 1.

For example, an electrode for an electrochromic device is generally composed of a substrate (1,8), a transparent first conductive material layer (2,7), and an electrochromic material layer (3,6). And a cathode together with the electrolyte to form an electrochromic device. In the present invention, the second conductive material such as metal is formed by forming the unevenness by the pattern 4 of the second conductive material layer such as metal on the first conductive material layer and laminating the electrochromic material layer according to the shape of the uneven surface. An electrochromic material layer 3 having an uneven surface which is the same as the uneven surface by the pattern 4 of the material layer can be formed. Since the electrochromic material layer 3 having the uneven surface as described above has a wider specific surface area than that of the planar shape, the contact area with the electrolyte 5 is widened, so that the amount of access of lithium ions increases and the electrochromic color is increased. Properties can be improved.

In addition, since the pattern 4 formed between the first conductive material layer 2 and the electrochromic material layer 3 uses a material having excellent electrical conductivity such as metal, the color change reaction time is improved by improving the electrical conductivity of the electrode. And discoloration uniformity in a large area can also be improved.

The substrate and the first conductive material layer of the present invention are not particularly limited as long as they are known to those skilled in the art as an electrode material, and preferably, may form a transparent electrode. Non-limiting examples of the substrate include glass, transparent polymer, and the like. Non-limiting examples of the first conductive material include indium doped tin oxide (ITO), antimony doped tin oxide (ATO), fluorine doped tin oxide (FTO), indium doped zinc oxide (IZO), and ZnO. It is possible. A method of forming a thin film by depositing a first conductive material on a substrate may also use a method known to those skilled in the art. Non-limiting examples thereof include sputtering, electron beam deposition, chemical vapor deposition (CVD), and sol gel coating.

The second conductive material forming the pattern between the first conductive material layer and the electrochromic material layer is not particularly limited in the present invention as long as the second conductive material is a material having higher electrical conductivity than the first conductive material, but is an oxide that is commonly used as the first conductive material. It is preferable that the metal has better electrical conductivity than the electrode material (ITO, ZnO, IZO, FTO), and non-limiting examples thereof include Ir, Ag, Cu, Au, Cr, Al, W, Zn, Ni, Fe, and Pt. , Pb, and alloys of the metal elements.

The method of patterning the second conductive material over the first conductive material layer is not particularly limited in the present invention. For example, by sputtering or electron beam depositing the second conductive material directly using a mask having a desired shape, a method of forming a partial pattern of the second conductive material on the substrate on which the first conductive material layer is formed may be used. Screen printing, inkjet printing, roll printing, photolithography and the like used may also be used.

In the case where the second conductive material layer is patterned and stacked on the first conductive material layer, the shape of the pattern can be seen as shown in FIGS. ), As shown in FIG. 1, the irregularities are formed by the pattern of the second conductive material layer. Since the electrode of the present invention has this type of unevenness, when depositing an electrochromic material layer on the unevenness, the electrochromic material layer also has the same unevenness and pattern shape and thus has a larger specific surface area than that of the planar shape. It becomes possible.

At this time, the thicker the thickness of the pattern of the second conductive material layer (as seen from the side of the substrate, the height of the unevenness), the greater the effect of widening the specific surface area of the electrochromic material layer. In order to inhibit transparency of the electrode, the present invention is preferably in the range of 100 nm to 900 nm.

In addition, when the width of the pattern of the layer of the second conductive material (the width of the pattern when viewed from the front of the substrate) is also too wide, it may impede the transmission of light and impede transparency of the electrode, in particular, the second conductive material. This may be so even with this metal. Thus, the preferred pattern width of the present invention may range from 50 nm to 300 nm.

In the present invention, it is preferable that the pattern of the second conductive material layer has a specific shape. In the case of the amorphous pattern without a specific shape, the specific surface area is not easy to control and the permeability of the electrode is difficult to control, so in the present invention, a pattern having a specific shape is preferable, for example, a pattern in which a certain shape is repeatedly arranged. Can be. For example, a linear repeating pattern as shown in FIG. 2, a lattice repeating pattern as shown in FIG. 3, or a concentric repeating pattern as shown in FIG. 4 may be used. In the present invention, the specific surface area of the electrochromic material layer is not limited to the above-described pattern, and any pattern having a particular shape may be included in the scope of the present invention.

In the case of the repeating pattern, the smaller the spacing between the patterns may increase the specific surface area, but since this may be a factor that hinders the transparency of the electrode, considering both these factors, the spacing between the patterns is preferably May range from 1 μm to 10 μm.

After forming the pattern-shaped unevenness of the second conductive material layer on the first conductive material layer as described above, when the electrochromic material is laminated, the electrochromic material layer has a curvature according to the uneven shape. This has the effect of widening the specific surface area.

In this case, the method of stacking the electrochromic material layer forms a thin film at a constant height from the base of the substrate along the surface profile of one surface of the substrate on which the first conductive material layer and the patterned second conductive material layer are formed. It is preferable that it is a method which can be performed, for example, vacuum deposition methods, such as sputtering. That is, when the substrate has a bend, the film must be formed at a constant height thereon at the high side on the substrate and at a constant height therefrom at the low side, so that the thin film can have the bend shape of the substrate as it is.

In the case of using a liquid coating method, the upper surface of the formed thin film is easy to have a flat shape regardless of the shape and irregularities of the substrate due to the surface tension of the liquid. Is not preferred.

The use of the electrode of the present invention is not particularly limited as long as it is an electrode that causes an oxidation or reduction reaction for an electrochemical device, but may be preferably used as an oxidizing electrode or a reducing electrode of an electrochromic device. Non-limiting examples of the electrochromic material that can be stacked on the electrode is NiO _x , LiNiO, V ₂ O ₅ , and CeO ₂ -TiO ₂ .

Meanwhile, the electrode of the present invention is as follows.

a) laminating a transparent first conductive material layer (2) on the substrate (1);

b) forming an unevenness by laminating a second conductive material layer 4 in a pattern form on a portion of the transparent first conductive material layer 2; And

c) stacking an electrochromic material layer 3 along the concave-convex shape; It may be prepared by a method comprising a.

The electrochromic device of the present invention may be manufactured by a conventional method known to those skilled in the art, except for including the electrode described above, the first electrode; Second electrode; Including an electrolyte, the first electrode and / or second electrode may be an electrode according to the present invention. For example, the first electrode and the second electrode may be manufactured by bonding a portion of the electrolyte injection hole with an adhesive containing a spacer and injecting and encapsulating the electrolyte.

On the other hand, the first electrode and the second electrode may act as an active electrode and an ion storage electrode, respectively. An active electrode is an electrode that performs electrochromic action in an electrochromic device, and an ion storage electrode is an ion storage electrode as a concept of a complementary electrode that can receive hydrogen or lithium ions desorbed from an active electrode containing an electrochromic material. It may also be electrochromic, including electrochromic materials. For example, when NiO and WO ₃ are respectively included in the first electrode and the second electrode, both electrodes may be active electrodes having electrochromic properties and may be ion storage electrodes for the counter electrode.

In this case, it may be said that it is advantageous in terms of efficiency of the device to maintain a balance because the ion storage capacity of the first electrode and the second electrode is the same, but in many cases, the ion storage of the first electrode and the second electrode may be reduced. If the electrode structure of the present invention is applied to a small-capacity electrode, it may be advantageous to maintain the balance of both electrodes to increase device efficiency.

In addition, in the present invention, since the electrical conductivity of the electrode is improved by the second conductive material layer, it is possible to exhibit excellent electrochromic properties even in a general size electrochromic device, but particularly 1 × 1㎡ ~ 2 × 2 It may be used for an electrochromic device having a large area of m 2, for example, a smart window or the like, to exhibit excellent electrochromic properties. In the case of the electrochromic device having a large area as described above, there may be a problem that discoloration occurs unevenly for each part due to disparity of discoloration reaction when the electrical conductivity of the electrode is inferior, but when the electrical conductivity of the electrode is improved by the present invention In the large-area device of the same size as above, it can induce a uniform discoloration reaction.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited thereto.

Example 1

After sputtering iridium (Ir) with a mask having a lattice slit (100 nm slit width, 5 μm gap between slits) on a glass substrate coated with ITO (100 mm x 100 mm), the mask was removed and the metal was removed. A transparent electrode with a pattern was prepared. The deposition thickness of iridium was set to 100 nm.

An ion storage electrode was fabricated by depositing NiO, an oxidative electrochromic material, using RF sputtering on the transparent electrode on which the metal pattern was formed. Deposition conditions are as follows.

Target: 6-inch disc type NiO sintered body

Ar flow rate: 70 ~ 90 sccm

Chamber pressure: 5 ~ 10mTorr

RF Power: 800 ~ 900W

Sputtering Time: 2 Hours

Deposition NiO Thickness: 500nm

Meanwhile, an active electrode was prepared by depositing a reducing electrochromic material WO ₃ having a thickness of 500 nm on an ITO-coated glass substrate by using RF sputtering.

An ultraviolet curing sealant was applied to the edge of the ion storage electrode, bonded to the active electrode to form an electrolyte injection portion, and then exposed to ultraviolet light for 5 minutes to cure the sealant. Thereafter, an acetamide and a lithium trifluoromethanesulfonimide (LiTFSI) eutectic mixture (mixing ratio of 5 g: 6 g) were injected using a vacuum injection method, and the injection portion was sealed with an epoxy adhesive. As shown in FIG. 1, electrochromic devices were manufactured by making electrode connecting portions using clips 10 and 80 at both ends of the active electrode and the ion storage electrode.

Applying a DC voltage to the electrochromic device prepared as described above (switching for 30 seconds at -1.5V, repeated for 30 seconds at + 1.5V) to induce coloration and decolorization reaction, the electrochromic properties were measured at that time . Electrochromism was measured by the transmittance measuring device (Avantes, Netherlands) to measure the extent to which light in the wavelength region of 350nm ~ 1200nm transmitted through the device and recorded a transmittance of 550nm, which is known to be the most sensitive to the naked eye among the visible region. As a result, the electrochromic device manufactured as described above had a transmittance of 23% when pigmented and 75% when decolorized after 500 times of initial driving. The reaction time took 2 seconds for complete reaction from decoloration to coloration and 1.5 seconds for complete reaction from coloration to decolorization.

 Comparative Example 1

An electrochromic device was manufactured and characterized in the same manner as in Example 1, except that Ir metal patterning was not performed on the ion storage electrode. As a result, after 500 cycles after the initial operation, the transmittance was 35% when staining and 64% when discoloring. Compared with the device of Example 1 containing metal patterning, the transmittance was about 12% higher during coloring and about 11% lower when discoloring. The reaction time was 3 seconds for complete reaction from decoloring to coloring and 2 seconds for complete reaction from coloring to decoloring.

According to the present invention, the area of contact between the electrochromic material layer and the lithium ions in the electrolyte in the electrochromic device is increased, and as the amount of lithium ions moves, the electrochromic properties such as transmittance difference during coloring / discoloration can be improved. As the conductive pattern is additionally provided, the electrical conductivity of the electrode is further improved, so that the discoloration reaction time may be shortened, and the discoloration uniformity in a large area may be improved. Therefore, it is possible to implement an electrochromic device having a large area and excellent discoloration characteristics.

Claims (12)

materials; A first conductive material layer; A patterned second conductive material layer; And an electrode in turn comprising an electrochromic material layer, And the second conductive material layer is stacked on a portion of the first conductive material layer in a pattern form to form an uneven portion, and the electrochromic material layer is stacked along the uneven shape. The method of claim 1, wherein the second conductive material is selected from the group consisting of Ir, Ag, Cu, Au, Cr, Al, W, Zn, Ni, Fe, Pt, Pb, and the alloy of the metal element. electrode. The electrode of claim 1, wherein a thickness of the pattern of the second conductive material layer is in a range of 100 nm to 900 nm. The electrode of claim 1, wherein the width of the pattern of the second conductive material layer is in a range of 50 nm to 300 nm. The electrode of claim 1, wherein a pattern of the second conductive material layer is repeatedly arranged in a predetermined shape. The electrode of claim 1, wherein an interval between patterns of the second conductive material layer is in a range of 1 μm to 10 μm. The electrode according to claim 1, which is used as an oxidizing electrode or a reducing electrode of an electrochromic device. a) laminating a first conductive material layer on the substrate; b) forming an unevenness by laminating a second conductive material layer in a pattern form on a portion of the first conductive material layer; And c) laminating an electrochromic material layer along the concave-convex shape; A method for producing the electrode according to any one of claims 1 to 7, including. The method of claim 8, wherein the lamination of the layer of electrochromic material is by vacuum deposition. A first electrode; Second electrode; And an electrochromic device comprising an electrolyte, wherein the first electrode, the second electrode, or both are the electrodes according to any one of claims 1 to 7. The electrochromic device according to claim 10, wherein an electrode having a small ion storage capacity among the first electrode and the second electrode is the electrode according to any one of claims 1 to 7. The electrochromic device according to claim 10, wherein the electrochromic device has a large area of 1 to 4 m 2.

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