JP2730139B2 - Electrochromic device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrochromic device (EC) device.

[Prior art] Conventionally, nickel (Ni) is contained as a material of a counter electrode of an EC element that performs display or dimming by using a substance (EC substance) that changes color by electrochemical oxidation or reduction, and contains an electrolyte. For example, those using polyvinyl alcohol, polyvinyl acetal, and the like have been proposed in JP-A-56-156818. However, the above-mentioned conventional EC element has a problem in life.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned disadvantages of the prior art and has not been known in the past.
The purpose is to provide a new EC element.

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and an electrochromic device comprising an electrode and a counter electrode formed on a substrate, an electrochemical coloring material and an electrolyte. The counter electrode contains NiO _x , and the x is 0.
5-2, wherein the electrolyte is propylene carbonate, γ-butyrolactone, sulfolane or 3-methylsulfolane with M ⁺ X ⁻ (where M is Li, Na or K, X is Cl
The present invention provides an electrochromic device characterized by using a solution in which an alkali metal salt represented by O ₄ , BF ₄ , CF ₃ SO ₃ , AsF ₆ or PF ₆ ) is dissolved.

FIG. 1 is a sectional view of a typical example of an EC device according to the present invention. In addition,% with respect to the composition is expressed by weight%.

In FIG. 1, reference numerals 1A and 1B denote substrates made of glass, plastic, or the like, an electrode 2A made of a transparent conductive film such as ITO on a first substrate 1A, and an EC material which is an electrochemical coloring material on the electrode 2A. Layer 3 is formed, and IT is formed on second substrate 1B.
A conductive layer 6 of O, SnO ₂ , metal or the like is formed, and a counter electrode 2B is formed thereon. The first substrate 1A and the second substrate
1B is a cell in which the electrode surfaces face each other and the periphery is sealed with a sealing material 4 to form a cell. A liquid electrolyte 5 exists between the substrates.

As the electrolyte 5, an organic electrolyte solution containing an alkali metal salt or a solution thickened with a polymer soluble therein is used. It is desirable that the conductivity is 10 ⁻⁴ S / cm or more and the viscosity is 10 ² to 10 ⁵ cps. As the organic electrolyte solution at that time, propylene carbonate, γ-butyrolactone, sulfolane or 3-methylsulfolane can be used, and as the alkali metal salt (M ⁺ X ⁻ ), M = Li, Na or K, X = ClO ₄ , BF ₄ , CF ₃ SO ₃ , AsF ₆
Or those which 0.1 to 1 mol / dissolved in the electrolyte solution or the like PF ₆ are preferred. The polymer used as a thickener is polymethyl methacrylate (PMMA), or ethylene oxide (PE).
O), polyprolene oxide (PPO), polyvinylpyrrolidone (PVP) and the like are preferably dissolved in the electrolyte solution containing the alkali metal salt in an amount of 1 to 30%.

In the present invention, as the substrates 1A and 1B constituting the EC element, ordinary substrates such as glass and plastic can be used. In the case of using a reflection type such as a mirror or a reflection type display element, one of the substrates may be an opaque substrate such as a metal, a ceramic, and a colored plastic.

As the electrode 2A, a transparent conductive film such as tin oxide (SnO ₂ ) or indium oxide / tin oxide (ITO) may be used as the electrode.

Further, in order to reduce these resistance values, a low-resistance material such as a metal such as aluminum, chromium, or titanium, or a conductive paste may be laminated in a linear or lattice shape. Further, it is convenient to form a terminal which can be soldered by plating or conductive paste at the end of the substrate, or to bond a lead to the outside by connecting a lead.

As the EC substance, a known EC substance such as a transition metal compound such as tungsten oxide (WO ₃ ) or molybdenum oxide (MoO ₃ ) or an organic EC substance may be used. Further, the thickness of the EC material layer 3 is preferably 0.5 to 2 μm in consideration of the response and the like.

The counter electrode 2B is formed by forming NiO _x on the conductive layer 6 by a method such as vacuum evaporation. _X of NiO _x needs to satisfy 0.5 ≦ x ≦ 2, and if x is less than 0.5, electrochromic properties are poor and complete erasure is difficult. When x is more than 2, there is a disadvantage that Ni becomes an unstable peroxide and is easily decomposed, and desirably falls within a range of 1 <x <2.

The counter electrode 2B has a thickness of 0.5 to 3 μm and a film density of 2 to 4 g /
cc, and an electric charge of 30 mC / cm ² or more is desirable in terms of durability and responsiveness.

When NiO _{x of the} counter electrode 2B is formed, LiO _x , IrO ₂ , Sn
5 to 20% of O ₂ , In ₂ O ₃ etc. or 3d of CrO _x , MnO _x , FeO _x , CoO _x etc.
5 transition metal oxides or rare earth oxides such as La ₂ O ₃ and CeO ₂
By doping up to 30%, the current capacity of the opposing electrode 2B is increased by 30 to 200%, and the responsiveness is desirably improved as compared with the case of using NiO _x alone.

[Operation] Since the EC element of the present invention has the above-described configuration, the electrolyte is not easily decomposed and the life is long.

Examples (Example 1) As shown in FIG. 1, a transparent conductive film and an EC material layer were sequentially laminated on a glass substrate, and a transparent conductive film and a counter electrode were sequentially laminated on a glass substrate. The gap was filled with an organic electrolyte so as to face each other. EC using transparent conductive film
The material layer was formed by vacuum-depositing 1 μm of WO ₃ . The counter electrode was formed by vacuum evaporation so as to have a NiO _0.8 film thickness of 2 μm.

The electrolyte used was one obtained by dissolving LiClO ₄ as an alkali metal salt in propylene carbonate at 1 mol / mol. Further, PMMA as a thickener was added to the liquid prepared as described above.
15% dissolved.

Thus was applied to DC2V the EC device produced, variation of 60-5% transmittance occurs, 10 ⁵ times driven even appearance, the deterioration of the responsiveness was hardly observed.

(Example 2) In the same manner as in Example 1, the counter electrode was made of NiO _{1.5 and} 1 μm thick.
And KClO ₄ , LiBF ₄ , NaCF ₃ SO ₃ , KAsF ₆ , LiP
Each F ₆ was 15 or an EC element using (15) produced as an electrolyte a material obtained by 0.5 mol / dissolved.

When a test similar to that of Example 1 was performed on these 15 samples, the result was almost the same as that of Example 1, and no abnormality was observed.

(Example 3) IrO ₂ , SnO ₂ , and In ₂ O ₃ were each doped by 8% when forming the counter electrode, and the other conditions such as the material of the counter electrode were exactly the same as those in Examples 1 and 2. When one sample corresponding to Example 1 and 15 samples corresponding to Example 2 were prepared for each of the above three oxides, Example 1,
As compared with the case of Example 2, the response was improved by about 50%.

Example 4 16 samples × 3 samples were prepared in the same manner as in Example 3 except that the doll of IrO ₂ , SnO ₂ and In ₂ O ₃ was 15%. The results were the same as in Example 3.

Example 5 LiO ₂ , Cr ₂ O ₃ , MnO ₂ , FeO, and CoO were used as doping substances, and the doping amount was 10%. The same sample as in Example 3 was used for each of the above substances. As a result, the results were almost the same as those in Example 3.

(Example 6) La ₂ O ₃ , CeO ₂ , and Eu ₂ O ₃ were used as doping substances, respectively, and the doping amount was set to 10%. The same samples as those in Example 3 were prepared for the respective substances described above. The results were almost the same as in Example 3.

(Comparative Example 1) An EC element was manufactured in the same manner as in Example 1, except that a counter electrode was formed so as to be NiO _0.3 , and the other conditions were exactly the same as in Example 1. This decoloring time was three times longer than in Example 1.

(Comparative Example 2) An EC element was manufactured in the same manner as in Example 1, except that a counter electrode was formed so as to have a NiO of _0.25 . This life was 1/5 that of Example 1.

[Effects of the Invention] The EC device of the present invention exhibits excellent durability and quick response, and greatly contributes to industry.

[Brief description of the drawings]

 FIG. 1 is a cross-sectional view of a typical example of an EC device according to the present invention. 1A, 1B: Substrate 2A: Electrode 2B: Counter electrode

Claims (1)

(57) [Claims] 1. An electrochromic device comprising an electrode and a counter electrode formed on a substrate, an electrochemical color-forming substance and an electrolyte, wherein the counter electrode contains NiO _x and x is in the range of 0.5 to 2. The electrolyte is propylene carbonate, γ-butyrolactone, sulfolane or 3
- methyl sulfolane M ⁺ X ^- (however, M is Li, Na or K, X is _{ClO 4, BF 4, CF 3} SO 3, AsF 6 or PF ₆₎ obtained by dissolving an alkali metal salt represented by An electrochromic device characterized by using: