JPS58115420A - Electrochromic display body - Google Patents

Abstract

PURPOSE:To realize a high response speed and a long life, by using activated carbon and carbon black for an opposed electrode, and using lithium borofluoride or lithium perchlorate, water, and propylene carbonate or gamma-butyl lactone, for an electrolyte. CONSTITUTION:As for an opposed electrode 4, that which has been press-molded by charging an expanded metal 5 of Ti into a core by use of carbon black or activated carbon powder, and a carbonxymethyl cellulose sodium is used. As for an electrolyte, that which has used lithium perchlorate or lithium borofluoride as an electrolyte, has used propylene carbonate or gamma-butyl lactone for a solvent, and has added water of 1.0-2.5wt% is used. When water is added, a response speed of ECD increases, because a part of H<+> is changed to Li<+> and is diffused into the display electrode, and it is caused by a fact that a diffusion speed of H<+> is higher.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display using an electrochemical redox reaction, and in particular to an electro-p1/o4 display (hereinafter abbreviated as KOD) using activated carbon or carbon black as a counter electrode material. It is something to do.

In general, mOD has a structure in which an electrolyte is interposed between the display electrode and the counter electrode, and a DC voltage is applied between the display electrode and the counter electrode, and a pattern is displayed by coloring or decoloring by applying current to the substance. This made it possible. In order to reversibly proceed with color development and color decolorization and obtain a long-life IC0D, the electrochemical reaction of the display electrode and the electrochemical reaction of the counter electrode that accompany color decolorization must be reversible.

The present applicant has previously discovered that activated carbon and carbon black have a fine structure, a three-dimensional chain structure, and a large surface area, so that electrochemical reactions proceed reversibly, and have used them as counter electrode materials. By doing so, we have provided a man who can meet with others in order to extend its lifespan. When a transition metal oxide such as WO is used for the display electrode, this man uses lithium perchlorate or lithium boro7tride as the electrolyte, propylene carbonate (p, o) or r, butyl lactone. By using a solution dissolved in (r-BL), an lOD with a long color development/decolorization driving life was obtained.

However, this IOD also had the following points to be improved. Response speed is 350-500sscC±
t, OV), which is rather slow.

The present invention has been made with the above points in mind. That is,
By adding 10 to 2.5 vt% of water to the electrolytic solution, the response speed of the IOD is increased, and an IOD with excellent life characteristics is created. The reason for the improvement in response speed of the IOD due to the addition of water is that in the conventional system, the rate at which L1+ in the electrolyte diffuses into the display electrode by applying a negative voltage to the display electrode was the rate determining factor. In the system of the present invention, this is expected to be because some H+ is converted to L1+ and diffused into the display electrode.

This is due to the fact that H+ has a smaller specific payon radius than -1+ and a higher diffusion rate.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Embodiment 1 First, a method for manufacturing an IC0D cell will be described with reference to FIG. On a transparent glass substrate 1 which has been washed with alkali, water and dried, approximately 300X of nzO@ is deposited by electron beam vacuum evaporation using a metal mask to form a transparent electrode 2. Next, a 10° section of the IO material was formed into a 50001 yM film by electron beam vacuum evaporation to form the display electrode 3. At this time, the substrate temperature was about 100° C. and a metal mask was used. Next, the counter electrode 4 is made by mixing the activated carbon powder with about 20 wt% sodium carboxymethylcellulose and about 50 vt% water, thoroughly kneading the mixture, and then using a hydraulic press using an extracted metal 5 made of T1 with a cut of about 2 cm as a core. It was press-molded. The press pressure at this time was 3 torr! /'-. After drying it at about 100° C. to remove moisture, a part of the end of this counter electrode was broken, and a Ti mesh 5 was taken out and a lead wire 6 made of T1 was spot welded to it to create a counter electrode 4. . Then, the previously prepared glass substrate 1 and the background container @ 9, which had been cleaned and dried and had holes for the liquid injection lower and the lead wire outlet 8, were bonded together. At this time, a white plate 10 and a counter electrode 4 were placed inside to provide contrast in the display, and the lead wire outlet 8 was also sealed. mO created in this way
Electrolyte 11 is injected into D cell from injection lower, and counter electrode 4 is injected.
After completely permeating the white plate 1o, the injection lower was sealed. The electrolyte is propylene carbonate.
1 of lithium borofluoride and 18 wt% of water were used.

The IOD configured in this way has an
The response speed was 240 sec+a.V and a bright blue color appeared, and the response speed was 180 .mu./cod at reverse voltage, which quickly disappeared. Furthermore, the service life of rectangular wave driving with a display and disappearance time of 300 m-5 ec has reached t3X'lo-* times and is still continuing.

Furthermore, for comparison, the response speed at ±1 V of the configuration 10D using an electrolytic solution in which IM/l of lithium borofluoride was dissolved in propylene carbonate was written as 43'Os.
-Red, erasure was 560 m m5ec.

Example λ mOD was prepared in the same manner as in Example 1, except that r-butyl lactone was used instead of the organic solvent propylene carbonate i used in Example 1. The response speed at ±1■ is 230 meters for writing and 160 meters for erasing, and the lifespan is 56 meters.
For comparison, the response speed at the same voltage is , writing 450m/beast, erasing 380s-
It was a flag.

Examples & The electrolyte lithium boroborofluoride used in Example 1 was replaced with 5 M/l of lithium perchlorate, 2 wt of water, and a propylene carbonate solution was used as the electrolyte, but the other configuration was the same as in Example 1. , created the IOD. The response speed at ±1 V is 250 m for writing and 190 m for erasing, and the life span is a5 x 10 times, which is currently continuing. Furthermore, for comparison, the above configurations X and D using a lithium perchlorate propylene carbonate solution with water addition + 7) Ny 1.5 M were written at the same voltage at 470 m -5ee.
It was a 570vm stable.

Example Instead of the electrolyte used in Example 1, α8M/l lithium perchlorate and L2vt% water were added to r-butyllactone droplets as the electrolyte, and the counter electrode used in Example 1 was also used. Material Ic0D was prepared using the same structure as in Example 1 except that acetylene black powder was used instead of activated carbon powder. ±1
The response speed at v is 220 鵠・ll! c. Erase 2
The life is 4.8×10 times and is currently being continued.

In addition, when using the above-mentioned electrolytic solution without water addition and a counter electrode, writing was 460 min/red and erasing was 4 at the same voltage.
30m - It was cod.

Furthermore, the life span of the comparative example in this example reached !L2X10- times with 4 oos''sc rectangular wave driving and is still being continued, but the driving voltage is ±1.2 V to provide the same consistency.

As the counter electrode material, activated carbon, carbon plastic\1,
■ In man using a tsuku, the response speed can be improved by adding water to lithium borosulfide and lithium perchlorate as an electrolyte, and using an electrolyte solution using propylene carbonate and r-butyllactone as solvents. Excellent performance and fast lifespan were obtained.

In addition, the reasons for limiting the components in the present invention are as follows:
If the amount of lithium fluoroborate or lithium perchlorate as an electrolyte is less than αI M / t, the conductivity of the electrolyte will be low, and the driving voltage will be higher than the water decomposition voltage, causing water electrolysis. Even if it exceeds L, the conductivity does not change much, and recrystallization occurs at low temperatures, so 1
1~2.0M/l&:l! Established. Furthermore, if the water content in the electrolytic solution is less than 1 wt%, the improvement in response speed due to the addition of water will not be noticeable, and furthermore, the response speed will likely change due to an increase in the number of blinks in the life test. In addition, if it exceeds 2.5vt%, the balance of the writing ratio becomes poor in the life test, and the so-called residual phenomenon is likely to occur.Furthermore, if left for a long time, VO is likely to be eluted into the liquid. −
Limited to 5vt%. Further, in the present invention, an example is shown in which VO, is used as the display material, but similar effects can be expected even when transition metal oxides such as MOO, RO, 08, etc. are used.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the cell structure of the MOD of the present invention. 1...Display electrode substrate 2...Transparent electrode 3...Display electrode 4...Counter electrode 5...Wire mesh 6... ...Lead wire 7...Liquid inlet 8...Lead wire outlet 9...Background container 10...White porous plate 11...More than electrolyte Applicant Kinsha Suwa Seikosha Co., Ltd. Representative Patent Attorney Tsutomu Mogami Figure 1

Claims (1)

[Claims] In an electrochromic main display consisting of a combination of a display material that can be colored and erased electrochemically, an electrolyte, and a counter electrode, the electrolyte is converted into propylene carbonate or r-butyl lactone (Ll to LOM/l of borosilicate). An electrochromic display comprising lithium heptadide or lithium perchlorate and 1.0 to 15 wt- of water, and using activated carbon or carbon black as a counter electrode.