RU2130630C1 - Electrochromic composition - Google Patents

Abstract

FIELD: image generation materials. SUBSTANCE: electrochromic composition appropriate for use in various- destination displays, auto-car rear-view mirrors, and in windows of residential and industrial buildings contains, wt %: quaternary dipyridinium or its derivative salt with following anions: ClO $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , BF $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , [C₂B₉H₁₂]^-, [(C₆H₅)₃CNB]^-, 0.7- 3.0; ferrocene or its derivative, 0.2-1.0; ferricinium or its derivative salt, 0.002-0.060; propylene carbonate or gamma- butyrolactone, the balance. Compositions possess increased stability and uniformity of electrically colored state. EFFECT: expanded possibilities of electrochromic devices. 3 cl, 13 ex

Description

 The invention relates to applied electrochemistry - electrochromism of organic compounds. Electrochromic compositions based on organic compounds are mainly used in devices with an electrically controlled amount of light absorption or light reflection, for example, displays for various purposes, car rear-view mirrors, both exterior and interior, windows of various residential and industrial complexes with regulation of the flow of solar radiation into the room, etc. .d.

Electrochromic compositions based on quaternary dipyridinium salts and ferrocene derivatives in such organic solvents as dimethylformamide (A. S. USSR N 566863), γ-butyrolactone (A. S. USSR N 722219, RU N 2009530 propylene carbonate (RU N 2009530) are known. The work of organic electrochromic materials in devices arranged vertically, the position most often used in practice, is complicated by the effect of gravitational separation of electroactivated component forms (Electrochemistry, 1977, v. 13, p. 404, Electrochemistry, 1985, v. 21, p. 918). Due to In order to reduce this effect, the time of complete bleaching of electrochromic light-attenuating devices increases significantly with increasing time of exposure to a control constant voltage.In order to reduce the effect of the delamination, thickeners — polymers (polyvinyl butyral, polymethylmethacrylate) are introduced into the electrochromic compositions to create a more viscous medium (A. S. USSR N 566863, A.S. USSR N 722219, Electrochemistry, 1977, v. 13 p. 404) or use quaternary dipyridinium salts with bulky anions, such as [C ₂ B ₉ H ₁₂ ] ^- (A.S. USSR N 972815, [(C ₆ H ₅ ) ₃ CNB] ^- (A.с) as cathodic components . USSR N 13346662).

 The use of an electrochromic composition containing quaternary dipyridinium salts with large anions in volume can significantly reduce the delamination effect in a number of solvents. However, for practical use of the composition, this is not enough in a number of applications, since due to the delamination effect, its decoloration time is large.

In a series by the patent of the company Gentex (see, for example, US 4902108, electrochromic compositions are considered, where quaternary dipyridinium salts were used as the cathodic component and 5,10-dihydro-5,10-dimethylphenazine previously proposed by us (Electrochemistry, 1977, v. 13, p. 404.) The authors of patent US 4902108 introduced polymethyl methacrylate as a thickener into electrochromic materials. Previously, we proposed such a solution for electrochromic compositions based on quaternary dipyridinium salts with small-volume anions and ferrocene derivatives (A . S. USSR N 722219) or 5,10-dihydro-5,10-dimethylphenazine (Electrochemistry, 1977, v.13, S. 404). The introduction of thickening polymers helps to reduce the "delamination" of the electroactivated components, and nevertheless This leads to the far from incomplete elimination of this negative effect.Therefore, with prolonged polarization of a vertically positioned electrochromic device, the separation of the colored state of the material in a qualitative form occurs in the same way as without the introduction of a polymer additive, namely, after a voltage loss, usually in the upper part In addition, the layer remains of a slowly bleaching layer of excess of the reduced form of the cathode component, and at the bottom there is a layer of increased concentration of the oxidized form of the anode component, which leads to an increase in the time of bleaching of the composition, since the electrochromic composition is nonuniformly colored. The closest among analogs to the claimed electrochromic compositions is the composition proposed in RU N 2009530, made on the basis of the cathode component - a quaternary salt of dipyridinium with small volume ClO anions $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ or bf $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , the anode component of ferrocene or a derivative thereof, dissolved in propylene carbonate or γ-butyrolactone. The composition was used in devices operating in the mode when the electrocoating time was small (no more than 15 s), and during this short period of time it showed no signs of heterogeneity of the electrocoating state. However, as shown by preliminary experiments (see also example 1), with a longer polarization time, the colored state of the composition becomes inhomogeneous, which leads to an increase in bleaching time, as well as to a decrease in its stability.

 The aim of this invention is the creation of electrochromic compositions with increased uniformity of the colored state and greater stability with a long polarization time.

 Such compositions will have a reduced bleaching time after prolonged electrocoating while maintaining the original light transmission.

This goal is achieved by introducing into the compositions based on quaternary salts of dipyridinium or its derivative and ferrocene or its derivative salts of ferricinium or its derivative. In this case, quaternary salts of dipyridinium or its derivative with large anions of [C ₂ B ₉ H ₁₂ ] ^- and [(C ₆ H ₅ ) ₃ CNB] ^- , as well as a mixture of quaternary salts of dipyridinium or its derivative with small and large anions in volume.

The claimed compositions have the following content of ingredients (wt.%):
1. Cathode component:
Quaternary salt of dipyridinium or its derivative with ClO anions $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ Bf $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , [C ₂ B ₉ H ₁₂ ] ^- , [(C ₆ H ₅ ) ₃ CNB] ^- - 0.7-3.0
Anode component:
Ferrocene or its derivative - 0.2 - 1.0
Additive:
Salt of ferricinium or its derivative - 0.002 - 0.060
Solvent:
Propylene Carbonate or γ-Butyrolactone - Else
2. The composition according to p. 1, characterized in that the cathodic component contains a mixture of the quaternary salt of dipyridinium or its derivative with a large anion of [C ₂ B ₉ H ₁₂ ] ^- or [(C ₆ H ₅ ) ₃ CNB] ^- and a quaternary salt of dipyridinium or a derivative thereof with a small volume ClO anion $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ or bf $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ with a content in the mixture of the latter 0.03-0.12 wt.%.

 3. The composition according to p. 1, characterized in that it may additionally contain a polymer - thickener in an amount of 0.5-1.5 wt.%.

A significant difference of the proposed solution is the introduction of a new additive into the well-known electrochromic composition - ferricinium salt or its derivative, expansion of the range of anions that are part of the quaternary salts of dipyridinium or its derivatives, as well as the use of a mixture of a quaternary dipyridinium salt or its derivative with a small volume anion and the same salt, but with a large anion. In this case, both liquid and polymer-thickened solvents can be used. As the quaternary salt of dipyridinium or its derivative, perchlorates, tetrafluoroborates, dicarboundecoborates, triphenyl cyanoborates of 4,4'-dipyridinium, 2,2'-dipyridinium, bis-1 ', 1''- dipyridinium with a nitrogen atom bonding alkylene group with 1 can be used -10 carbon atoms; bis-2,2'-pyridinium or bis-4 ', 4''- pyridinium with a phenylene linking group or a keto group, as well as one and the other in various combinations. As the quaternizing groups of the pyridine rings of dipyridines, there can be independent from each other alkyl groups with 1-10 carbon atoms, phenyl and benzyl groups, phenyl or benzyl groups with different alkyl substituents on each benzene ring with 1-4 carbon atoms halides (Cl, Br, I), alkoxy groups or cyano groups, as well as alkylene linking groups with 2-4 carbon atoms for 2,2'-dipyridinium derivatives. In addition, pyridine rings
The method of measuring the integral light transmission is used the same as in the patent prototype [3].

 The proposed solutions confirm the following examples, showing a comparison of the claimed electrochromic compositions with the known ones (including the composition of the prototype - example 1).

 Example 1. To test the compositions, electrochromic devices were made, which are two rectangular optically transparent ITO electrodes glued together along the perimeter with epoxy-based adhesive with spacers that determine the thickness of the interelectrode space. In this case, the electrodes were shifted relative to each other to form metal contacts for supplying electrical voltage from the greater side of the device. The internal space of the device was filled with a vacuum method using an electrochromic composition through a gap of an adhesive seam 2 mm wide and sealed with silicone sealant. The adhesive and sealant used were inert with respect to the electrochromic material.

The compositions were tested in two comparative electrochromic devices with optically transparent electrodes 40x50 mm ^{2 in} size. The surface resistance of the conductive coatings was 6-8 Ohm / □. The thickness of the layer of electrochromic material was 0.015 cm. The first device was filled with a solution of 0.8% 1,1'-dimethyl-4,4'-dipyridinium diperchlorate and 0.5% ferrocene oil, which is a mixture of mono-, di- and tritretbutyl derivatives of ferrocene in propylene carbonate (prototype). The second device was filled with the same solution, but additionally containing a mixture of perchlorates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.060%. Both cells were arranged vertically and placed on the smaller side, which did not have current-carrying contacts. A voltage of 1.09 V was applied to the first device, and 1.20 V to the second device. The indicated voltage values made it possible to have the same attenuation of transmission in both cells and, correspondingly, the same concentration of colored forms of the components in both devices. After continuous polarization of both devices for 72 h and subsequent closure of the electrodes, the second device was completely decolorized before the initial light transmission in 17 min 05 s, while the first one in 2 h 12 min with a decrease in the maximum light transmission of ~ 5%.

Example 2. Two electrochromic devices with dimensions of optically transparent ITO electrodes 55x130 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first is 1.1% 1,1'-dimethyl-4, 4'-dipyridinium didicarboundecarborate, 0.6% ferrocene oil in propylene carbonate; the second - with the same solution, but with the addition of perchlorates of mono-, di- and tritetbutyl derivatives of ferricinium in a total concentration of 0.017%. The distance between the electrodes was 0.015 cm. Both cells were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. The polarization of both devices was carried out under a voltage of 1.20 V. In this case, the attenuation of light transmission were the same in both cells. After 12 hours, the voltage was turned off and at the same time, the electrodes were short-circuited. The second device completely bleached after 5 minutes and 15 seconds, while the first after 45 minutes, while the color cast of the electrochromic layer in the cell changed, and light transmission decreased by 3% compared to the original.

Example 3. Two electrochromic devices with dimensions of optically transparent ITO electrodes 50x126 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first was 1.5% 1,1'-dimethyl-4 , 4'-dipyridinium ditriphenylcyanborate, 0.5% ferrocene oil in propylene carbonate; the second - with the same solution, but with the addition of perchlorates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.041%. The distance between the electrodes was 0.015 cm. Both cells were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. In order to ensure the same attenuation of light transmission, the polarization of the first device was carried out under a voltage of 0.92 V, and the second - 1.10 V. After 13 hours, the polarization was turned off and the electrodes were shorted. The second device was completely discolored in 6-7 s, while the first - in 50 minutes, while the color cast of the electrochromic layer in the cells changed slightly, and the light transmission decreased by 2% compared to the original.

 Example 4

a) Two electrochromic devices with dimensions of optically transparent ITO electrodes 55x130 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first was 1.8% 1,1'-dimethyl-4, 4'-dipyridinium didicarboundecaborate, 1.0% ferrocene oil in propylene carbonate; the second - with the same solution, but with the addition of tetrafluoroborates of mono-, di- and tritetbutyl derivatives of ferricinium in a total concentration of 0.017%. The distance between the electrodes was 0.015 cm. Both devices were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the top, and the "plus" - at the bottom. Both devices were polarized at a voltage of 1.20 V. When the light transmission was weakened, they were close in value in both devices. After 30 minutes, the voltage was turned off and the electrodes were short-circuited. The second device bleached for 20 s, while the first 3 min 25 s.

 b) Voltage was applied to the electrochromic devices used above so that the “plus” was at the top and the “minus” at the bottom. Both devices were polarized at a voltage of 1.20 V for 1 h, followed by short-circuiting of the electrodes. In this case, the second device was discolored in 5 minutes, while the first in 8 minutes.

Example 5. Two electrochromic devices with dimensions of optically transparent ITO electrodes 50x70 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first is 0.7% 1,1'-dibenzyl-4 , 4'-dipyridinium didicarboundecaborate, 0.2% ferrocene oil in propylene carbonate; the second - with the same solution, but with the addition of ferricinium perchlorate with a concentration of 0.002%. The distance between the electrodes was 0.015 cm. Both devices were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the top, and the "plus" - at the bottom. The polarization of both devices was carried out at a voltage of 1.5 V. In this case, the attenuation of light transmission was the same in both devices. After 1 h, the voltage was turned off and the devices remained open. The second device discolored in 40 seconds, while the first in 4 minutes and 30 seconds.

Example 6. Two electrochromic devices with dimensions of optically transparent ITO electrodes 50x130 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first - 1.1% 1,1'-dimethyl-4 , 4'-dipyridinium didicarboundecaborate, 0.6% ferrocene oil, a mixture of perchlorates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.017% in propylene carbonate; the second is 1.0% 1,1'-dimethyl-4,4'-dipyridinium didicarboundecaborate, 0.09% 1,1'-dimethyl-4,4'-dipyridinium diperchlorate, 0.6% ferrocene oil, a mixture of mono- perchlorates , di- and tritrebutyl derivatives of ferricinium in a total concentration of 0.017% in propylene carbonate. The distance between the electrodes was 0.015 cm. Both cells were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. Both devices were polarized at a voltage of 1.20 V for 12 h, after which the electrodes were shorted. The first device bleached for 6 minutes, the second for 5-6 seconds.

Example 7. Two electrochromic devices with dimensions of optically transparent ITO electrodes 95x160 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first is 0.7% 1,1'-dimethyl-4 , 4'-dipyridinium didicarboundecaborate, 0.08% 1,1'-dimethyl-4,4'-dipyridinium diperchlorate, 0.5% ferrocene oil, a mixture of perchlorates of mono-, di- and tritetbitul derivatives of ferricinium in a total concentration of 0.009% in propylene carbonate ; the second - 0.6% 1,1'-dimethyl-4,4'-dipyridinium didicarboundecaborate, 0.12% 1,1'-dimethyl-4,4'-dipyridinium dipochlorate, 0.5% ferrocene oil, a mixture of mono perchlorates -, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.009% in propylene carbonate. The distance between the electrodes was 0.02 cm. Both cells were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. The polarization of both devices was carried out at a voltage of 1.20 V for 12 h, followed by turning off the power source and simultaneously shorting the electrodes. In this case, the second device was completely discolored in 22 minutes, while the first one took more than 2 hours.

Example 8. Two electrochromic devices with the dimensions of optically transparent electrodes 100x170 mm ² and the resistance of conductive coatings of SnO ₂ doped with fluorine, 15 Ohm / □ are made as in example 1 and filled with electrochromic compositions: the first is 0.8% 1,1'- dimethyl-4,4'-dipyridinium didicarboundecaborate, 0.5% ferrocene oil in propylene carbonate; the second - 0.6% 1,1'-dimethyl-4,4'-dipyridinium didicarboundecaborate, 0.13% 1,1'-dimethyl-4,4'-dipyridinium dipochlorate, 0.5% ferrocene oil, a mixture of mono perchlorates -, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.006% in propylene carbonate. The distance between the electrodes was 0.02 cm. Both cells were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. Both devices were polarized at a voltage of 1.50 V. The attenuation of light transmission was the same. After 12 hours, the voltage was turned off and at the same time, the electrodes were short-circuited. The first device was discolored in 38 minutes, the second in 7-9 seconds.

Example 9. Two electrochromic devices with dimensions of optically transparent ITO electrodes 55x130 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first 1.1% 1,1'-dimethyl-4, 4'-dipyridinium didicarboundecaborate, 0.6% ferrocene oil, a mixture of tetrofluoroborates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.017% in propylene carbonate; the second 1.1% 1,1'-dimethyl-4,4'-dipyridinium didicarboundecaborate, 0.03% 1,1'-dimethyl-4,4'-dipyridinium dipochlorate, 0.6% ferrocene oil, a mixture of tetrafluoroborates mono- , di- and tritrebutyl derivatives of ferricinium in a total concentration of 0.017% in propylene carbonate. The distance between the electrodes was 0.015 cm. Both devices were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. Both devices were polarized at a voltage of 1.20 V. The attenuation of light transmission was the same in both devices. After 12 hours, the voltage was turned off and the electrodes were short-circuited. The second device completely discolored in 4 minutes 50 seconds, while the first - in 5 minutes 20 seconds.

 Example 10

a) Two electrochromic devices with dimensions of optically transparent ITO electrodes 40x50 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first - 1.0% 1,1'-dimethyl-4, 4'-dipyridinium ditetrafluoroborate, 0.7% ferrocene oil, 0.5% polymethylmethacrylate in γ-butyrolactone; the second - with the same solution, but with the addition of a mixture of perchlorates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.060%. The distance between the electrodes was 0.015 cm. Both cells were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. The polarization of both devices was carried out at a voltage of 1.20 V for 12 h, followed by the closure of the electrodes until completely discolored, and then at a voltage of 1.50 V. The attenuation of transmission in the electrostained state was close. After 12 h of secondary polarization, the electrodes were shorted. In this case, the first device was completely discolored in 15 minutes 20 seconds, the second in 4-5 seconds.

 b) A voltage was applied to the electrochromic devices so that the “plus” was at the bottom, the “minus” at the top. The polarization of both devices was carried out under a voltage of 1.22 for 4 hours, followed by the closure of the electrodes. In this case, the first device was completely discolored in 5 minutes 30 seconds, the second - 4-5 seconds.

Example 11. Two electrochromic devices with dimensions of optically transparent electrodes 40x50 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first 1.3% 1,1'-diheptyl-4,4 ' -dipyridinium diperchlorate, 0.7% ferrocene oil, 1.5% polymer — cellulose acetyl propionate in propylene carbonate; the second - with the same solution, but with the addition of phenylferricinium perchlorate at a concentration of 0.029%. The distance between the electrodes was 0.015 cm. Both devices were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was at the bottom, the "plus" - at the top. The first device was polarized at a voltage of 1.20 V, the second - 1.18 V for 12 hours, followed by short-circuiting of the electrodes. The attenuation of light transmission in the electrostained state of the compositions was close in value. In this case, the first device discolored in 3 minutes 10 s, the second in 8-10 s.

Example 12. Two electrochromic devices with dimensions of optically transparent ITO electrodes 40x50 mm ² with a resistance of conductive coatings of 6-8 Ohm / □ were made as in Example 1 and filled with electrochromic compositions: the first was 0.04 M trimethylene bis [4- (1 '-benzylpyridin-4'-yl) -pyridinium] tetra (tetrafluoroborate), 0.8% ferrocene oil, dissolved in a 1.5% solution of poly- (N-vinyl-2-pyrrolidone) in γ-butyrolactone, the second is the same a solution, but with the addition of a mixture of tetrafluoroborates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.017%. The distance between the electrodes was 0.015 cm. Both devices were arranged vertically and placed on the larger side with current-carrying contacts. The voltage was applied so that the "minus" was attached to the bottom of the device, and the "plus" up. The first device was polarized at a voltage of 1.18 V, the second - 1.17 V for 8 hours and the subsequent closure of the electrodes until completely discolored. The attenuation of light transmission was close in value. The first device discolored in 3 minutes 05 seconds, the second in 10 seconds.

Example 13. Two electrochromic devices with sizes of optically transparent ITO electrodes 52x130 mm ² and a resistance of conductive coatings of 6-8 Ohm / □ were made as in example 1 and filled with electrochromic compositions: the first - 1.1% 1,1'-dimethyl-4 , 4'-dipyridinium didicarboundecaborate, 0.6% ferrocene oil in propylene carbonate; the second - with the same solution, but with the addition of perchlorates of mono-, di- and tritretbutyl derivatives of ferricinium in a total concentration of 0.017%. The distance between the electrodes was 0.015 cm. Both cells were placed horizontally and placed in a heating cabinet at a temperature of 80 ^o C. After heating the devices to a predetermined temperature, a voltage of 1.45 V was applied to them. The polarization mode was cyclic. Cycle - 3 hours of polarization / 0.5 hours with short-circuited electrodes. The number of cycles was 6, that is, the total polarization time at a voltage of 1.45 V and a temperature of 80 ^o C was 18 hours. At the end of the tests, the electrochromic composition in the first device acquired a blue tint, and light transmission decreased by 7%; the second device remained unchanged while maintaining the original light transmission.

 The upper concentration limit was determined by the solubility of the quaternary salts of dipyridinium derivatives in the declared solvents, and the lower limit was unsuitable for the practical use of light absorption of the electrostained state. The lower concentration limit of the thickener polymer was determined by the ineffective effect of lower concentrations on the bleaching time, and the upper limit is associated with the difficulty of filling the sealed electrochromic devices with the thickened compositions.

 In the case where the mixture of quaternary salts of dipyridinium or its derivative with different anions in volume was used as the cathodic component, the lower limit of the amount of salt with a small anion volume was determined by the insignificant effect on the composition bleaching time (Example 9), and the upper one is associated with sufficient compensation for the delamination effects of electroactivated forms component with long polarizations for the actually used resistances of optically transparent electrodes in electrochromic devices.

 As can be seen in the above examples, the addition of salts of ferricinium or its derivative in the known compositions, including the composition of the prototype (example 1) leads to a decrease in the time of discoloration after a long stay of the composition in the electrocolored state. The bleaching of the claimed composition (example 1) is faster by about 8 times compared with the prototype. This confirms the increased uniformity of the electrostained state of the claimed composition in comparison with the composition of the prototype. Similar data were obtained in the case of compositions based on quaternary salts of dipyridine derivatives with large anions in volume (Example 2-5), using mixtures of quaternary salts of dipyridinium derivatives with different volumes of anions (Example 6-9), as well as in the case of polymer-thickened solvents (example 10-12). In all cases, in the claimed compositions, the bleaching time is in wide limits and decreases from 1.1 to ~ 430 times.

 In addition, as can be seen from examples 1-3,13, with prolonged electrocoating, the light transmission of the claimed compositions with subsequent decoloration does not change, unlike the known solutions, which indicates greater stability of the electrocoated state of the compositions.

 The proposed compositions with increased stability and uniformity of the electrostained state will make it possible to manufacture electrochromic devices with wider capabilities without signs of a change in their initial characteristics.

Claims (2)

1. The electrochromic composition, including the cathodic component — the quaternary dipyridinium salt, the anodic component — ferrocene or its derivative, and the solvent — propylene carbonate or γ-butyrolactone, characterized in that the cathodic component contains the quaternary salt of dipyridinium or its derivative with ClO anions $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ Bf $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , [C ₂ B ₉ H ₁₂ ] ^- , [(C ₆ H ₅ ) ₃ CNB] ^- and additionally an additive - a salt of ferricinium or its derivative in the following ratio of components, wt.%:
Quaternary salt of dipyridinium or its derivative with ClO anions $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ Bf $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , [C ₂ B ₉ H ₁₂ ] ^- , [(C ₆ H ₅ ) ₃ CNB] ^- - 0.7 - 3.0
Ferrocene or its derivative - 0.2 - 1.0
Ferricinium salt or its derivative - 0.002 - 0.060
Propylene Carbonate or γ-Butyrolactone - Else
2. The composition according to claim 1, characterized in that as the cathode component it contains a mixture of the quaternary salt of dipyridinium or its derivative with a large anion of [C ₂ B ₉ H ₁₂ ] ^- or [(C ₆ H ₅ ) ₃ CNB] ^- and the quaternary salt of dipyridinium or its derivative with a small volume ClO anion $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , or BF $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ , with the content in the mixture of the last 0.03 - 0.12 wt.%.  3. The composition according to claim 1, characterized in that it further comprises a thickener in an amount of 0.5 to 1.5 wt.%.