Electrochromic element with improved electrolyte layer

Patent metadata

Field	Value
Publication number	US-2018088426-A1
Application number	US-201615560215-A
Country	US
Kind code	A1
Filing date	Mar 21, 2016
Priority date	Mar 24, 2015
Publication date	Mar 29, 2018
Grant date	—

Abstract

The invention relates to an electrochromic element comprising two substrates having electrically conductive insides, a layered operating electrode which comprises a metal complex compound and which is capable of entering into a redox reaction where the transition from the oxidized to the reduced state is attended by an increase of color depth and the transition from the reduced to the oxidized state is attended by a corresponding weakening of color, an electrolyte layer in the form of a transparent, flexible film, and a counterelectrode [ATI(D1] which is capable of intercalating mobile cations of the electrolyte material and/or of entering into a redox reaction in which when the material of the second electrode changes from the oxidized to the reduced state it exhibits no increase of color depth in the wavelength region of the increase of color depth of the metal complex compound and preferably is not subject to any increase of color depth at all, where the electrolyte layer comprises at least the following components: (a) a crosslinkable hybrid prepolymer, (b) a crosslinkable organic monomer or prepolymer, (c) a non-crosslinkable, thermoplastic organic polymer, and a dissociable salt whose inorganic cations can, in the presence of a charge difference between the operating electrode and the counterelectrode, move between the said electrodes. The electrochromic element is more particularly suitable as constituent of automobile glazing systems.

First claim

What is claimed is:

1 . Electrochromic element, comprising
a first and a second substrate, wherein each of the first and second substrates is transparent for visible light and has an electrically conductive surface on its side facing inwardly toward the electrochromic cell, a layered operating electrode which is in contact with the electrically conductive surface of a first of the two substrates and has a metal complex compound which is capable of entering into a redox reaction, where the transition from the oxidized to the reduced state is attended by an increase of color, and the transition from the reduced to the oxidized state is attended by a corresponding weakening of color, an electrolyte layer which is located between the operating electrode and the other substrate and contains movable metal cations, a counterelectrode located between the electrolyte material and the conductive coating of the other substrate, which is capable of intercalating mobile cations of the electrolyte material and/or of entering into a redox reaction, where the material of the second electrode is not subjected to an increase of color depth in the wavelength region of the increase of color depth of the metal complex compound during the transition from the reduced to the oxidized state, wherein the electrolyte layer is a transparent, flexible film that is produced using at least the following components: (a) a crosslinkable hybrid prepolymer, (b) a crosslinkable organic monomer or prepolymer, (c) a non-crosslinkable thermosplastic organic polymer and (d) a dissociable salt whose inorganic cations can, in the presence of a charge difference between the operating electrode and the counterelectrode, move between said electrodes.

2 . Electrochromic element according to claim 1 , wherein the prepolymers of the electrolyte layer are present in crosslinked form.

3 . Electrochromic element according to claim 1 , wherein the crosslinkable hybrid prepolymer (a) is an organic silicic acid(hetero)polycondensate and/or wherein the crosslinkable organic monomer or prepolymer (b) is an organic compound which is capable of undergoing a polymerization reaction, in particular a C═C addition polymerization, and/or wherein the non-crosslinkable, thermoplastic polymer (c) is selected from the group consisting of polyacrylates, acrylate ester polymers and polyethers as well as copolymers containing (poly)acrylate, an acrylate ester polymer and/or a polyether.

4 . Electrochromic element according to claim 3 , wherein the crosslinkable hybrid prepolymer (a) has groups, which are bonded to silicon via carbon, with organically crosslinkable or organically crosslinked residues, in particular (meth)acrylic groups, norbornenyl groups or epoxy groups, and/or wherein the crosslinkable organic monomer or prepolymer (b) contains at least one group per molecule that has one or more C═C double bonds, in particular vinyl-, acrylate-, methacrylate groups, or at least one epoxy group and/or wherein the non-crosslinkable, thermoplastic polymer (c) is selected from the group consisting of poly(methyl methacrylates), ethyl methacrylate-methyl acrylate copolymers and optionally acrylate-functional poly(propylene oxide-ethylene oxide)-copolymers.

5 . Electrochromic element according to claim 1 , wherein the electrolyte layer further comprises:
(e) a solvent or a solvent mixture and/or (f) nanoparticles.

6 . Electrochromic element according to claim 5 , wherein the solvent has a boiling point greater than about 130° C., preferably greater than about 160° C. and more preferably greater than about 200° C., or wherein one component of the solvent mixture contains a solvent having such a boiling point.

7 . Electrochromic element according to claim 5 , wherein the surface of the nanoparticles is unmodified or modified and the material of the nanoparticles is selected from the group consisting of metal oxides, mixed metal oxides and mixtures of metal (mixed) oxides.

8 . Electrochromic element according to claim 5 , wherein the material of the nanoparticles is selected from the group consisting of SiO 2 , TiO 2 , Al 2 O 3 , ZnO, ZrO 2 , and Ta 2 O 5 , and mixtures thereof and/or wherein the primary particle size of the nanoparticles is below 100 nm, preferably below 20 nm.

9 . Electrochromic element according to claim 1 , wherein the metal complex compound of the operating electrode has at least one chelating complexing ligand which can bind metal atoms via two or more nitrogen-, oxygen- or sulfur atoms, with at least some of the two or more nitrogen-, oxygen-, or sulfur atoms of the complexing ligand having free electron pairs.

10 . Electrochromic element according to claim 9 , wherein the at least one chelating complexing ligand contains at least one aromatic hetero ring selected from the group consisting of bis(benzimidazolyl)pyridine that is unsubstituted or substituted with OH or with halogen, bis(benzoxazolyl)pyridine that is unsubstituted or substituted with OH, alkoxy, nitro or, halogen, terpyridine that is unsubstituted or substituted with halogen, alkyl, alkoxy, OH, nitro, or aminophenyl, and ligands that contain two terpyridine residues bound together via a single bond or via a divalent spacer, in particular via a hydrocarbon-containing residue, that are unsubstituted or substituted with halogen, alkyl or aminophenyl.

11 . Electrochromic element according to claim 9 , wherein the metal atoms of the chelating complexing ligands are selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd or a mixture thereof, in particular from iron ions.

12 . Electrochromic element according to claim 10 , comprising an operating electrode having
a) a combination of at least two Fe-MEPE with different ligand structures, or b) a combination of at least one Fe-MEPE with a different MEPE having the same ligand structure, but containing a different cation, preferably a Ru-MEPE, or c) a combination of one Fe-MEPE with a different MEPE having a different ligand structure and containing a different cation, preferably a Ru-MEPE.

13 . Electrochromic element according to claim 12 , wherein the different MEPEs are arranged as a mixture in one layer or separately in two overlying layers.

14 . Electrochromic element according to claim 9 , wherein the operating electrode further contains an embedding material having hydroxy groups and non-aromatic, organic polymerizable C═C double bonds that functions as a matrix for the chelating complexing ligands.

15 . Electrochromic element according to claim 14 , wherein the embedding material is composed of at least 70 wt. % of an organic material and/or of a silicic acid(hetero)polycondensate relative to the embedding material.

16 . Electrochromic element according to claim 15 , wherein the embedding material
either (i) comprises units which are selected from the group consisting of
(a) organic compounds in which each molecule carries at least one hydroxy group and at least one organically polymerizable C═C double bond,
and/or
(b) residues of an organically modified silicic acid(hetero)polycondensate bonded to silicon atoms by carbon, wherein each of these residues carries at least one hydroxy group and at least one organically polymerizable C═C double bond,
and/or
(ii) comprises a mixture of at least two different units, wherein a first unit is substituted with at least one hydroxy group and a second unit carries at least one organically polymerizable C═C double bond, with the proviso that these units are either residues of an organically modified silicic acid(hetero)polycondensate

Assignees

• Fraunhofer Ges Forschung
• Bayerische Motoren Werke Ag

Inventors

• Posset Uwe
• Joost Christine
• Schott Marco
• Clade Jurgen
• Muller Christine
• Beck Matthias
• Pinsker Martin
• Bokor Tamas Gellert
• Meszaros Robert

Classifications

• C09K2211/187

  of the iron group metals, i.e. Fe, Co or Ni · CPC title

• G02F2001/1519

  Physics · mapped topic

• C08J2451/00

  Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers · CPC title

• C09K2211/1007

  Non-condensed systems · CPC title

• G02F1/155

  Electrodes · CPC title