WO2019030270A1

WO2019030270A1 - Article for production of or use in an electrochromic device

Info

Publication number: WO2019030270A1
Application number: PCT/EP2018/071481
Authority: WO
Inventors: Michael Goebel
Original assignee: Basf Se
Priority date: 2017-08-09
Filing date: 2018-08-08
Publication date: 2019-02-14
Also published as: TW201920596A

Abstract

The present invention relates to compositions (also referred to as inks) comprising electrochromic nanoobjects, to an article for production of or use in an electrochromic device, to a process for producing said article and to a process for preconditioning a multilayer structure for production of or use in an electrochromic device.

Description

Article for production of or use in an electrochromic device

Electronic devices e.g. optoelectronic devices or electrochromic devices often contain functional layers comprising nanoobjects, e.g. nanoobjects comprising an electrochromic material. US 8,593,714 B2 discloses an electrochromic device comprising a pair of electrodes separated by an electrolyte layer, wherein one of the said electrodes comprises an electrochromic material, an ion-conductive binder and conductive nanowires. More specifically, said electrode comprises particles which are electrochromic and are bound together with a binder which is ion conductive. This electrode also has a network of electronically conductive nanowires.

US 8,593,714 B2 does not provide detailed information regarding the manufacturing of an electrode comprising an electrochromic material, an ion-conductive binder and conductive nanowires, although this is not a trivial issue, at least due to the large number of different constituents (electrochromic material, nanowires, ion conductor, binder) which have to interact in such electrode in order to fulfill different functions (electrochromism, electronic conduction, ionic conduction, matrix-building). The large number of different constituents may cause problems with regard to their chemical compatibility. Furthermore, in order to allow expedient manufacturing of such electrodes by printing or other wet processing techniques, compositions (also referred to as inks) are needed wherein the non-soluble constituents of the electrode (particles of electrochromic material as well as electronically con- ductive nanowires) are suspended, beside those constituents which are in the dissolved state. It is well known that suspensions of nanoobjects have limited stability because suspended nanoobjects tend to agglomerate.

Ion conductors typically used for electrochromic composite electrodes like those disclosed in US 8,593,714 B2 are electrolytes comprising cations selected from the group consisting of H⁺, Li⁺, Na⁺, and K⁺. Unfortunately, high concentrations of such electrolytes have a detrimental influence on the stability of suspended nanoobjects against agglomeration and settling. Thus, inks for preparation of electrochromic devices containing such electrolytes have to be used shortly after preparation, and only low concentrations of suspended nanoobjects are possible in order to avoid agglomeration and settling. In order to facilitate preparation of electrochromic composite electrodes by wet processing techniques, it is desirable to increase the storage stability and the concentration of suspended nanoobjects in such inks.

Related art is also

JP 2008 287001 A

NAJAFI-ASHTIANI NAMED ET AL: "A dual electrochromic film based on nanocomposite of copolymer and WO3 nanoparticles: Enhanced electrochromic coloration efficiency and switching response", JOURNAL OF ELECTROANALYTICAL CHEMISTRY, ELSEVIER, AMSTERDAM, NL, vol. 774, 30 April 2016 (2016-04-30), pages 14-21 , XP029593937, ISSN: 1572-6657, DOI: 10.1016/J.JELECHEM.2016.04.046

US 6, 175,441 B1.

According to a first aspect of the present invention, there is provided a composition (A-0) comprising

(a) nanoobjects comprising one or more electrochromic oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon

(c) a carrier liquid having a boiling point below 120 °C

(d) one or more kinds of polymerizable moieties (e) optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties

(f) optionally one or more organic polymers suspended or dissolved in said carrier liquid

(g) an aprotic organic liquid having a boiling point of 120 °C or higher

wherein in said composition (A-0) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 2 ppm or less, preferably 0.02 ppm or less, most preferably 0.002 ppm or less.

As used herein, "ppm" means "part per million" with respect to the total weight of the composition. A composition according to the present invention is in the form of a suspension, also referred to as a slurry. In the context of certain technical application fields, such composition is also referred to as an ink. Preparation of suspensions is known in the art. The term "suspension" denotes a dispersion comprising a continuous phase (in the literature sometimes referred to as an external phase e.p.) that is liquid and at least one dispersed phase (in the literature sometimes referred to as an internal phase i.p.) that is solid and does not dissolve in said continuous phase which is liquid. In a suspension which forms a composition according to the present invention, the nanoobjects (a) form a dispersed phase, which is dispersed within the liquid external phase. The external liquid phase consists of the above-defined liquid constituents (c) and (g) and any constituents which are dissolved in said liquid constituents.

Surprisingly it has been found that an electrochromic electrode obtained from an ink as described above which virtually does not contain cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ can subsequently be provided with sufficient ionic conductivity in a multilayer structure for production of or use in an electrochromic device. This is achieved by allowing migration or diffusion of ions of an electrolyte comprising cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ as defined above from one or more other layers of said multilayer structure into said composite layer.

The constituents of the composition according to the invention are now described in detail.

According to ISO TS 27687:2008 (as published in 2008), the term "nanoobject" refers to an object having one, two or three external dimensions in the nanoscale, i.e. in the size range from approximately 1 nm to 100 nm. According to ISO TS 27687:2008, nanoobjects having one external dimension in the nanoscale, while the other two external dimensions are significantly larger, are generally referred to as nanoplates. Said one external dimension in the nanoscale corresponds to the thickness of the nanoplate. The two significantly larger dimensions differ from the na- noscale dimension by more than three times. The two larger external dimensions are not necessarily in the nanoscale. Another common term for denoting a nanoobject having one external dimension in the nanoscale, while the other two external dimensions are significantly larger, is "nanoflake".

According to ISO TS 27687:2008, nanoobjects having two similar external dimensions in the nanoscale, while the third external dimension is significantly larger, are generally referred to as nanofibers. The third significantly larger dimension differs from the nanoscale dimensions by more than three times. The largest external dimension is not necessarily in the nanoscale. Said largest external dimension corresponds to the length of the nanofibers. Nanofibers typically have a cross section close to circular shape. Said cross section ex- tends perpendicularly to the length. Said two external dimensions which are in the nanoscale are defined by the diameter of said circular cross section.

Electrically conductive nanofibers are also referred to as nanowires. Hollow nanofibers (irrespective of their electrical conductivity) are also referred to as nanotubes. Nanoobjects having two similar external dimensions in the nanoscale, while the third external dimension (length) is significantly larger, which are rigid (i.e. not flexible) are commonly referred to as nanorods. Nanoobjects having two similar external dimensions in the nanoscale, while the third external dimension (length) is significantly larger, and have a cross section close to rectangular shape extending perpendicularly to the length, are commonly referred to as nanoribbons. According to ISO/TS 27687:2008, nanoobjects having all three external dimensions in the nanoscale, wherein the length of the longest axis and the length of the shortest axis of the nanoobject differ not significantly, are generally referred to as nanoparticles. The length of the longest axis and the length of the shortest axis differ by not more than three times.

Approximately isometric nanoparticles, i.e. the aspect ratio (longest : shortest direction) of all three orthogonal external dimensions is close to 1 , are commonly referred to as nano- spheres. Preferably, the nanoobjects of constituent (a) of the present invention are nanoparticles. Preferred nanoparticles are approximately isometric, i.e. the aspect ratio (longest : shortest direction) of all 3 orthogonal external dimensions is in the range of from 1 to 2. Especially preferred nanoparticles are nanospheres. Particularly preferred nanoparticles are primary particles having a primary particle diameter of 1 nm to 100 nm, preferably 3 nm to 50 nm (measured by nitrogen absorption, X-ray diffraction or transmission electron microscopy). Preferred are nanoparticles having a primary particle diameter of less than 20 nm, more preferably less than 15 nm, further preferably 12 nm or less. According to DIN 53206-1 : 1972-08, the term "primary particles" refers to entities which are discernible as individuals by means of optical microscopy or transmission electron microscopy.

Advantageously, the nanoobjects are nanoparticles which in suspension have a hydrody- namic size D90 of less than 100 nm (measured by dynamic light scattering or centrifugal sedimentation techniques). Said nanoobjects (a) comprise one or more electrochromic oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon. More preferably, said nanoobjects (a) consist of one or more electrochromic oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the ex- ception of carbon. As used herein, "elements of groups 12, 13 and 14" refer to elements of groups 12, 13 and 14 of the periodic table of the elements according to lUPAC notation.

Electrochromic materials are characterized by an ability to change their optical properties, reversibly, and persistently, when a voltage is applied across them (see Claes G. Granqvist, Solar Energy Materials & Solar Cells 99 (2012) 1-13). This ability is herein also referred to as the "electrochromic effect". A change of the optical absorption of the electrochromic material occurs when electrons are transferred to or away from the electrochromic material. Certain electrochromic materials have the property of exhibiting a change, evocation, or bleaching of color (in the visible range of the electromagnetic spectrum) as effected either by an electron-transfer (redox) process or by a sufficient electrochemical potential (see Mortimer, R. J.: "Electrochromic materials", Annu. Rev. Mater. Res. 201 1 , 41 :241-68). However, as used herein, the term "electrochromic material" is not limited to materials exhibiting a change, evocation, or bleaching of color (i.e. in the visible range of the electromagnetic spectrum). Thus, materials changing their optical absorption, e.g. in the UV or IR range of the electromagnetic spectrum without a visible color change, are herein also referred to as "electrochromic".

Electrochromic metal oxides are known in the art, see e.g. Mortimer, R. J.: "Electrochromic materials", Annu. Rev. Mater. Res. 201 1 , 41 :241-68 and Granqvist, C. G.: "Oxide electro- chromics: An introduction to devices and materials", Solar Energy Materials & Solar Cells 99 (2012) 1-13.

Preferably said nanoobjects (a) comprise or consist of one or more electrochromic oxides of Ti, Ni, Zn, Y, Zr, Nb, Mo, Cd, Ce, Hf, Ta, W, Ag, La, Pr, Nd, Sm, Eu, Si, Sn, Pb, In, V and Ir. More preferably said nanoobjects (a) are nanoparticles (as defined above) comprising, preferably consisting of, one or more electrochromic oxides of Ti, Ni, Zn, Y, Zr, Nb, Mo, Cd, Ce, Hf, Ta, W, Ag, La, Pr, Nd, Sm, Eu, Si, Sn, Pb, In, V and Ir.

More preferably, said nanoobjects (a) comprise one or more oxides of nickel, preferably consist of one or more oxides of nickel, or comprise one or more oxides of tungsten, preferably consist of one or more oxides of tungsten. Especially preferably, said nanoobjects (a) are nanoparticles comprising one or more oxides of nickel, preferably consisting of one or more oxides of nickel, or nanoparticles comprising one or more oxides of tungsten, preferably consisting of one or more oxides of tungsten.

Preparation of nanoobjects (a) comprising one or more electrochromic metal oxides is known in the art. For instance, said nanoobjects (a) are nanoparticles synthesized by a gas phase pyrolysis process, preferably flame spray synthesis. Such nanoparticles are commercially available.

In certain cases, it is preferred that the composition further comprises

(b) one or more metal salts of formula (I)

(M^a+)z(Z^b )y (I),

wherein

M^a+ represents a metal cation,

Z^b_ represents the corresponding salt anion,

a is 2, 3, 4 or 5, b is 1 , 2 or 3,

z is the least common multiple of a and b, divided by a

y is the least common multiple of a and b, divided by b.

Thus, when a is 2 and b is 1 , z is 1 and y is 2

Thus, when a is 2 and b is 2, z is 1 and y is 1

Thus, when a is 2 and b is 3, z is 3 and y is 2

Thus, when a is 3 and b is 1 , z is 1 and y is 3

Thus, when a is 3 and b is 2, z is 2 and y is 3

Thus, when a is 3 and b is 3, z is 1 and y is 1

Thus, when a is 4 and b is 1 , z is 1 and y is 4

Thus, when a is 4 and b is 2, z is 1 and y is 2

Thus, when a is 4 and b is 3, z is 3 and y is 4

Thus, when a is 5 and b is 1 , z is 1 and y is 5

Thus, when a is 5 and b is 2, z is 2 and y is 5

Thus, when a is 5 and b is 3, z is 3 and y is 5

Preferred are metal salts of formula (I) wherein

M represents a metal selected from the group consisting of transition metals, rare earth metals, Mg, Ca, Sr, Ba, Al, In, Ga, Sn, Pb, Bi, Zn, Cd, and Hg, preferably from the group consisting of Ni, Cu, Zn, Al, In, Sc, La, Ce and Y

or

Z^b_ represents an anion selected from the group consisting of acetate, formiate, citrate, oxalate, nitrate, difluorophosphate, and weakly coordinating anions whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid.

More specifically, preferred are metal salts of formula (I) wherein

and Z^b~ represents an anion selected from the group consisting of acetate, formiate, citrate, oxalate, nitrate, difluorophosphate, and weakly coordinating anions whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid.

In preferred metal salts of formula (I), Z^b~ is a weakly coordinating anion whose correspond- ing acid has an acidity higher than the acidity of 100 % sulfuric acid, b = 1 , z = 1 and y = a.

The term "weakly coordinating anion" is known in the art, see e.g. I. Krossing and I. Raabe, Angew. Chem. Int. Ed. 2004, 43, 2066 - 2090. Weakly coordinating anions (sometimes referred to as non-coordinating anions) are stable on their own and do not have a propensity to donate electrons to an electron acceptor. These anions readily release their respec- tive cations because their negative charge is delocalized over a large area of non-nucleo- philic and chemically robust moieties. The coordinating ability of each anion is limited by its most basic site; it will always coordinate with its most nucleophilic, sterically accessible moiety. Therefore, the acidity of the corresponding acid is a measure for the coordinating ability of the anion. Acids having an acidity higher than the acidity of pure sulfuric acid (100 % sulfuric acid) are known in the art and are also referred to as "superacids".

The term acidity, as used herein, refers to the acidity in the solvent 1 ,2-dicloromethane according to the equilibrium superacidity scale proposed by A. Kiitt et al., J. Org. Chem. Vol. 76, No. 2, 2011 and may be determined by the method described therein. Compositions comprising nanoobjects (a) and metal salts (b) of formula (I) having an anion Z selected from the group consisting weakly coordinating anions whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid are described in a patent application filed by the same applicant on the same day as the present application.

Preferably in said salts of formula (I) said anion Z^" is selected from the group consisting of (Z-1 ) [BX4]^" wherein

X is selected from F, -OTeFs, -CN and R

(Z-2) [X3B-E-BX3]^" wherein

X is selected from F, -OTeFs, -CN and R

and E is selected from F and CN (Z-3) [CBiiHi2-mXm]- wherein

X is selected from F, CI, Br, I and R;

and m is an integer selected from the range of 1 to 12

(Z-4) [CBgH-io-mXm]^" wherein

X is selected from F, CI, Br, I and R;

and m is an integer selected from the range of 1 to 10

(Z-5) [AIX₄]- wherein

X is selected from F, CI, Br, I, -OR, R, and -OC{X'_mR3-m} wherein m is an integer selected from the range of 0 to 3 and X' is selected from F, CI, Br, I and -OR

(Z-6) [X3AI-E-AIX3]- wherein

X is selected from of F, CI, Br, I, -OR, R, and -OC{X'_mR3-m} wherein m is an integer selected from the range of 0 to 3 and X' is selected from F, CI, Br, I and -OR and E is selected from CN and F

(Z-7) [ΕΧβ]^" wherein

E is selected from P, As and Sb

X is selected from F, CN, -OTeFs and R

(Z-8) [X5E-A-EX5]^" wherein

E is selected from P, As and Sb

X is selected from F, CN, -OTeFs, and R;

A is selected from F and CN

(Z-9) [E(S0₂X)m]- wherein

X is selected from F and R;

E is selected from O, N and C

m is an integer selected from the range of 1 to 3; m = 1 for E = O; m = 2 for E = N; m = 3 for E = C;

(Z-10)[N(OPR₂)₂]-

(Z-13) N(CN)₂- wherein in the anions selected from the group consisting of (Z-1 ) to (Z-13) R, if present, is selected from the group consisting of

CnH2n+i pFp, wherein n is an integer selected from the range of 1 to 16 and p is an integer selected from the range of 0 to (2n + 1 )

- CnH(2n-i) pFp, wherein n is an integer selected from the range of 2 to16 and p is an integer selected from the range of 0 to (2n - 1 )

CnH(2n-3)-pFp, wherein n is an integer selected from the range of 2 to 16 and p is an integer selected from the range of 0 to (2n - 3)

C6H(5-n)-pFp(CH3 qFq)n, wherein n is an integer selected from the range of 0 to 5, p is an integer selected from the range of 0 to 5 and q is an integer selected from the range of 0 to 3.

Preferably in said salts of formula (I) said cation M^a+ is selected from the above-defined preferred cations M^a+, and the anion Z^b~ is selected from the above-defined preferred anions Z^". Preferred anions are above-defined anions (Z-9) wherein X is F or Cnh i-pFp, herein n is an integer selected from the range of 1 to 16 and p is an integer selected from the range of 0 to (2n + 1 ).

Especially preferred metal salts of formula (I) are zinc diacteate, aluminium triacetate, yttrium triacetate, zinc dinitrate, aluminium trinitrate, yttrium trinitrate, scandium bis(trifluoro- methane)sulfonimide, yttrium bis(trifluoromethane)sulfonimide, aluminum bis(trifluoro- methane)sulfonimide, lanthanum bis(trifluoromethane)sulfonimide, cerium bis(trifluoro- methane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosulfonyl)imide, zinc bis(fluorosulfonyl)imide, yttrium trifluoromethylsulfonate, aluminum trifluoromethyl- sulfonate, lanthanum trifluoromethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate.

Metal salts of formula (I) as defined above are commercially available.

It is preferred that the metals M of the metal salts of formula (I) differ from the metals of the metal oxides in the metal oxide nanoobjects dispersed in said first suspension.

Without being bound to theory, it is believed that the metal salts of formula (I) as defined above act as dispersing aids for the nanoobjects (a) and are at least partly physisorbed on the surface of the nanoobjects (a), and may be partly dissolved in the carrier liquid (c) of the suspension. The term "dispersing aid" as used herein denotes a substance which facilitates the separation of suspended particles and acts to prevent or suppress agglomeration or settling of said particles. In the context of the present invention the term "dispersing aid" is used for metal salts of formula (I) as defined herein which stabilize said suspended nanoobjects (a). Use of certain metal salts of formula (I) as dispersing agents for nanoobjects is described in WO 2016/128133 A1.

In the composition according to the present invention, the surfaces of the nanoobjects (a) are at least partly coated with physisorbed metal salts of formula (I). The term physisorp- tion, as used herein, defines adsorption in which the forces involved are intermolecular forces (van der Waals or electrostatic forces) and which do not involve a significant change in the electronic orbital patterns of the species involved. In the context of the present application, "physisorption" denotes the adsorption of a molecule or ion on a surface by either electrostatic or van der Waals attraction. In contrast to chemisorption, a physisorbed molecule or ion does not alter its chemical properties upon adsorption. Accordingly, by physisorption covalent bonds are neither formed nor broken nor are atoms ionized or ions deionized or subject to a change of their charge.

Coating of nanoobjects (a) by said one or more metal salts of formula (I) may be achieved by procedures known in the art, see e.g. WO 2016/128133 A1 which is incorporated herein by reference. For instance, said carrier liquid (c) and said nanoobjects (a) are combined, for example by mixing, ultrasonication or ball milling. To the obtained initial suspension, one or more metal salts (b) of formula (I) as defined above are added. Coating of the nanoobjects (a) with the one or more metal salts (b) of formula (I) as defined above takes place during mixing at room temperature or upon heating. Alternatively, said carrier liquid (c) and said one or more metal salts (b) of formula (I) are combined, for example by mixing. To the obtained initial solution of one or more metal salts (b) of formula (I) in the carrier liquid (c), the nanoobjects (a) are added. Coating of the nanoobjects (a) with the one or more metal salts of formula (I) as defined above takes place during mixing at room temperature or upon heating.

Preferably, in a composition according the present invention, the molar percentage of metal ions M^a+ of the metal salts (b) of formula (I) is in the range of from 0.02 to 6 mol%, based on the total amount of

the mols of metal in the metal ions M^a+ of the metal salts (b) of formula (I) and the mols of metal in the metal oxides in the nanoobjects (a). If the above-defined molar percentage is below 0.02 %, the amount of the metal salts of formula (I) may be not sufficient to achieve the above-described effect of suppressing agglomeration and settling of the nanoobjects (a). If the above-defined molar percentage is above 6 %, in an electrochromic composite layer (see below) prepared from a composition according to the invention the amount of nanoobjects (a) comprising one or more electro- chromic compounds as defined above may be not sufficient for achieving an appropriate electrochromic effect.

Especially if the nanoobjects (a) comprise or consist of one or more oxides of nickel, it is preferred that a metal salt (b) according to formula (I) is present in the composition according to the first aspect of the present invention.

The carrier liquid (c) is merely a vehicle for wet processing and usually does not remain in the layer to be formed from the above-defined composition.

Said carrier liquid (c) has a polarity index > 4 according to the polarity scale, based on the polarity index of water being 9 (V.J. Barwick, Trends in Analytical Chemistry, vol. 16, no. 6, 1997, p.293ff, Table 5).

Preferably, said carrier liquid has a boiling point of less than 120 °C. The boiling point refers to the standard pressure of 101 .325 kPa.

Said carrier liquid is not polymerizable.

Preferably said carrier liquid is selected from the group consisting of water, alcohols, amines, carbonic acids, esters, ketones, organic carbonates, polyethers, sulfides and ni- triles and mixtures thereof. More preferably, said carrier liquid is selected from the group consisting of water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso- butanol, tert.-butanol, 2-butanone, 2-pentanone, methyl isobutyl ketone, dimethyl carbonate, ethyl methyl carbonate, 1 ,2-dimethoxy-ethane, acetonitrile, pyridine, propionitrile, dimethylamine, formic acid, acetic acid, ethyl acetate, dimethoxyethane, acetone, dimethyl carbonate, dioxane, trifluoromethyl methyl carbonate, ethyl methyl carbonate, 2-methyltet- rahydrofuran, chloroform and mixtures thereof.

Preferred carrier liquids are selected from the group consisting of water, ethanol, methanol, 2-propanol, 2-methyl tetrahydrofuran, and mixtures thereof. Especially if the nanoobjects (a) comprise or consist of one or more oxides of tungsten, preferably said carrier liquid (c) is a mixture comprising water and one or more of the above- mentioned organic liquids having a boiling point of less than 120 °C. In this case it is further preferred that the above-described constituent (b) is not present in the composition accord- ing to the first aspect of the present invention. Preferably, in this case said carrier liquid is a mixture comprising water and one or more organic liquids selected from the group consisting of ethanol, methanol, 2-propanol, 2-methyl-tetrahydrofuran, and mixtures thereof.

A composition according to the invention further comprises

(d) one or more kinds of polymerizable moieties. The term "polymerizable moieties" as used herein includes polymerizable monomers and polymerizable oligomers.

Said polymerizable moieties (d) are dissolved in the liquid phase of the composition.

Said polymerizable moieties (d) are precursors of a polymer matrix. In the process of preparing a layer from the above-defined composition, said polymerizable moieties form a polymer matrix by polymerization on a surface of a solid substrate to which the above- defined composition has been applied. In a layer obtained from an above-defined preferred composition according to the present invention, said matrix binds and accommodates the nanoobjects (a) and optionally further constituents (see below) within said layer, fills the voids between said nanoobjects (a), provides mechanical integrity and stability to the layer and binds the layer to the surface of the solid substrate.

Preferably said polymerizable moieties are selected from the group consisting of alkyl acrylates, alkyl methacrylates, hydroxyalkyi acrylates, hydroxyalkyi methacrylates, vinyl chloride, vinyl fluoride, acrylonitrile, vinylidene fluoride, vinylidene chloride, hexafluoropropyl- ene, trifluoroethylene, tetrafluoroethylene, tetrahydrofuran, vinylpyrrolidone, polyisocya- nates in combination with polyols and/or diamines.

Most preferably, said polymerizable moieties are co-polymerizable monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and from the group consisting of hydroxyalkyi acrylates and hydroxyalkyi methacrylates. Herein preferably the molar ratio between the total amount of monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and the total amount of monomers selected from the group of hydroxyalkyi acrylates and hydroxyalkyi methacrylates is in the range of from 0.0002 to 50000, preferably 0.4 to 400. Preferably said polymerizable monomers are butyl acrylate and hydroxybutyl acrylate.

In cases where the polymerizable moieties (d) are polymerizable by radical polymerization, said composition preferably further comprises

(e) one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties.

Suitable initiators are known in the art and commercially available. Preferably, said initiators are selected from the group consisting of compounds which decompose into radicals when exposed to electromagnetic irradiation. Optionally, a composition according to the invention further comprises

(f) one or more organic polymers suspended or dissolved in the liquid external phase of the composition.

In the process of preparing a layer from the composition said polymers are incorporated in the above-defined matrix. The polymers (f) are either dissolved in the liquid external phase of the composition, or -in case they are not soluble in said liquid phase - they are present in the form of particles which are suspended within said liquid phase.

Preferably said polymers (f) are selected from the group consisting of polyalkyl acrylates, polyalkyl methacrylates, polyhydroxyalkyl acrylates, polyhydroxyalkyl methacrylates, poly- vinyl chloride, polyvinyl fluoride, polyacrylonitrile, polyvinylidene fluoride, polyvinylidene chloride, polyhexafluoropropylene, polytrifluorethylene, polytetrafluoroethylene, polytetra- hydrofuran, polyvinylpyrrolidone, polyurethanes, polyethylene oxides.

A composition according to the invention further comprises

(g) an aprotic organic liquid having a boiling point of 120 °C or higher. The boiling point refers to the standard pressure of 101.325 kPa.

In the composition according to the present invention, said aprotic organic liquid (g) is mixed with the carrier liquid so that a common liquid phase exists in the above-defined composition. Accordingly, the carrier liquid (c) having a boiling point below 120 °C and the aprotic organic liquid (g) having a boiling point of 120 °C or higher are selected to be mis- cible.

Said aprotic organic liquid is selected to have a boiling point of 120 °C or higher, in order to allow said aprotic organic liquid (g) to remain in a layer prepared from the above-defined composition, when heat is applied during the steps of removing the carrier liquid and polymerizing the polymerizable moieties.

Said aprotic organic liquid (g) is not polymerizable.

Said aprotic organic liquid (g) is selected to be capable of allowing for dissolution and dis- sociation of an electrolyte comprising cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ when such electrolyte enters a layer prepared from a composition according to the present invention by migration or diffusion (for further details, see below).

Preferably said aprotic organic liquid (g) is selected from the group consisting of organic carbonates, alcoholes, amides, carboxylic acid esters, ethers, polyethers, ketones, lac- tones, lactames, phosphoric acid esters, sulfones, sulfoxides, sulfonates, urea, thiourea, derivatives of urea resp. thiourea, and mixtures thereof. Derivatives of urea resp. thiourea are compounds wherein one or more of the hydrogen atoms of urea resp. thiourea are substituted. Examples are ethylene urea (2-lmidazolidon) Ν,Ν'-dimethylpropylene urea, N- (2-hydroxyethyl)ethylene urea and the corresponding thiourea derivatives. Most preferably, said aprotic organic liquid (g) is selected from the group consisting of ethylene carbonate, 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, 1 ,2-butylene carbonate, 1 ,3-butylene carbonate, 1 ,4-butylene carbonate, 2,3-butylene carbonate, ethylene glycol, diethylene glycol, diethyl carbonate, gamma-butyrolactone, gamma-valerolactone, sulfolane, dimethyl sulfoxide, 1 ,3-dimethyl-3,4,5,6-tetrahydro-2(1 H)-pyrimidinone (DMPU) and mixtures thereof.

Especially preferred are ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3- propylene carbonate and mixtures thereof. Optionally, a composition according to the invention further comprises

(h) electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14. Said electronically conductive nanoobjects (h) form a dispersed phase, which is dispersed within the liquid external phase of the composition according to the present invention.

In a layer prepared from the above-defined preferred composition, said electronically conductive nanoobjects may form a conductive network of adjacent and overlapping electronically conductive nanoobjects capable of carrying an electric current (see below). Preferably said electroconductive nanoobjects (h) have two external dimensions in the range of from 1 nm to 100 nm, and their third external dimension is in the range of from 1 μιη to 100 μιτι, in each case determined by transmission electron microscopy. Typically, said two external dimensions which are in the range of from 1 nm to 100 nm are similar i.e. they differ in size by less than three times. The third dimension of said electroconductive nanoobjects is significantly larger, i.e. it differs from the other two external dimensions by more than three times. Preferably, said electroconductive nanoobjects (h) are nanowires as defined in ISO TS 27687:2008 (as published in 2008) (for details, see above).

Preferably, the electronically conductive nanoobjects (h) are nanowires having a length in the range of from 1 μητι to 100 μιτι, preferably of from 3 μιτι to 50 μιτι, more preferably of from 10 μιτι to 50 μιτι, and a diameter in the range of from 1 nm to 100 nm, preferably of from 2 nm to 50 nm, more preferably of from 15 nm to 30 nm, length and diameter in each case being determined by transmission electron microscopy.

Preferably, said electronically conductive nanoobjects are nanowires comprising materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel. More preferably, said electronically conductive nanoobjects are nanowires consisting of materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel. A composition according to the present invention which contains the above-defined constituents (a), (c), (d) and (g) and optionally one, more or all of the above-defined constituents (b), (e), (f), and (h) contains a single continuous liquid phase comprising the constituents (c) and (g) which at standard pressure 101.325 kPa are liquid at temperatures below 120 °C, and constituent (d) and - if present - constituent (e) and constituent (f) (if present in the form of soluble polymers) which are dissolved in said liquid phase. Constituents (a) and - if present - constituent (h) and constituent (f) (if present in the form of polymer particles) each form a dispersed phase, which is dispersed within the liquid external phase.

A composition according to the present invention which contains the above-defined constituents (a), (c), (d) and (g) and optionally one, more or all of the above-defined constituents (b), (e), (f), and (h) may be used for preparing a composite layer which in an electro- chromic device can function as an electrochromic electrode.

A composite layer obtainable from a composition according to the first aspect of the present invention, which contains the above-defined constituents (a), (c), (d), (g) and optionally one, more or all of the above-defined constituents (b), (e), (f) and (h), comprises

a matrix formed of one or more organic polymers formed by polymerization of the polymerizable moieties (d)

and dispersed within said matrix

(b) optionally one or more metal salts according to formula (I)

(g) an aprotic organic liquid having a boiling point of 120 °C or higher, wherein in said composite layer the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less.

Optionally (in case the composition according to the first aspect of the present invention comprises the above-defined optional constituent (h)), said composite layer as defined above further comprises

(h) electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 dispersed within said matrix formed of one or more organic polymers.

The term composite layer denotes a layer comprising discrete nanoobjects (a) comprising one or more electrochromic oxides as defined above and constituents (g) and optionally (h) dispersed within a continuous phase (matrix) extending throughout said layer. Further constituents may be dispersed in the matrix, each fulfilling a specific function and interacting with the other constituents.

Within the composite layer, the matrix provides mechanical integrity and stability and binds and accommodates the above-defined constituents of the composite layer which are dispersed within said matrix. Without being bound to theory, it is believed that the nanoobjects (a) comprising one or more electrochromic oxides as defined above and - if present - the electronically conductive nanoobjects (h) as defined above, which are dispersed within the matrix, form a network extending throughout the composite layer providing for the transport of electrons towards and away from the nanoobjects (a). Without being bound to theory, it is believed that in the composite layer said aprotic organic liquid (g) as defined above is confined within pores extending through the matrix. When an electrolyte comprising cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ from an external source (see below) enters the composite layer by migration or diffusion, said aprotic organic liquid (g) allows for dissolution and dissociation of said electrolyte, thus providing a network for the transport of ions to and away from the nanoobjects (a). Thus, a composition according to the invention which may be used for preparing a composite layer as defined above comprises

precursors (in the form of polymerizable moieties (d) and optionally dissolved or suspended polymers (f)) of the organic polymer matrix of the composite layer, and the above-defined constituents (a), (g) and optionally (h) of the composite layer which are to be dispersed within said organic polymer matrix, and

a carrier liquid (c) having a boiling point of less than 120 °C which does not become a constituent of the composite layer but merely acts as a vehicle for wet-processing, and is substantially free of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺. This is a significant advantage since it was found that electrolytes containing cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ have a detrimental influence on the stability of suspended nanoobjects against agglomeration and settling. Thus, the invention provides inks comprising suspended nanoobjects (a) wherein said inks have an increased storage stability and allow for increased concentrations of suspended nanoobjects (a). In turn, sufficient ionic conductivity of the layer prepared from a composition according to the invention is achievable when subsequently an electrolyte enters a layer prepared from a composition according to the present invention by migration or diffusion.

Preferably, in a composition (A-0) according to first aspect of the present invention

(a) the total amount of said nanoobjects comprising one or more electrochromic oxides is in the range of from 0.1 wt.-% to 20 wt.-%, preferably 0.5 wt.-% to 10 wt.-%,

(b) the total amount of said salts of formula (I) is in the range of from 0 wt.-% to 2 wt.- %, preferably 0 wt.-% to 1 wt.-%,

(c) the amount of said carrier liquid is in the range of from 70 wt.-% to 99.5 wt.-%, preferably 88 wt.-% to 99 wt.-%,

(d) the total amount of polymerizable moieties is in the range of from 0.005 wt.-% to 7.0 wt.-%, preferably 0.21 wt.-% to 2.5 wt.-%,

(e) the total amount of said initiators is in the range of from 0.00001 wt.-% to 0.06 wt.- %, preferably 0.0001 wt.-% to 0.05 wt.-%,

(f) the total amount of said polymers is in the range of from 0 wt.-% to 7.0 wt.-%, preferably 0.21 wt.-% to 2.5 wt.-%,

(g) the amount of said aprotic organic liquid having a boiling point of 120 °C or higher is in the range of from 0.00009 wt.-% to 1 wt.-%, preferably 0.005 wt.-% to 0.7 wt.-%,

(h) the total amount of said electronically conductive nanoobjects is in the range of from 0 wt.-% to 0.9 wt.-%, preferably 0 wt.-%to 0.4 wt.-%,

in each case based on the total weight of the composition,

The concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ may be determined by means of pH measurement (H⁺) and inductively coupled plasma optical emission spectrometry (Li⁺, Na⁺, K⁺). This method has a detection limit of 30 ppt (parts per trillion). This method is known in the art.

Preferably, in said composition, the ratio between

(a) the total weight of said nanoobjects comprising one or more electrochromic oxides and

(h) the total weight of said electronically conductive nanoobjects

is in the range of from 1 to 1000, preferably 5 to 300.

At a weight ratio above 1000, in a composite layer prepared from a composition according to the invention, the amount of electronically conductive nanoobjects (h) may be not sufficient to have a remarkable effect on the electronic conductivity. On the other hand, at a weight ratio below 1 , in a composite layer prepared from a composition according to the invention the amount of nanoobjects (a) comprising one or more electrochromic oxides as defined above may be not sufficient for achieving an appropriate electrochromic effect. Further preferably, the ratio between

(d) the total weight said polymerizable moieties

and the total weight of

(a) said nanoobjects comprising one or more electrochromic oxides

(g) said aprotic organic liquid having a boiling point of 120 °C or higher

(h) said electronically conductive nanoobjects

is in the range of from 0.00002 to 70, preferably 0.018 to 4.95.

At a weight ratio below 0.00002, the amount of polymerizable moieties in the composition may be not sufficient for forming a matrix which is capable of binding and accommodating the constituents (a), (g), and (h) as described above when a composite layer is prepared from a composition according to the invention. On the other hand, at a weight ratio above 70, the amount of the constituents (a), (g) and (h), which determine the electrochromic effect and other important properties of a composite layer prepared from a composition according to the present invention may be not sufficient to achieve the desired properties.

Further preferably the ratio between

(c) the weight of the carrier liquid

and

(a) the total weight of nanoobjects comprising one or more electrochromic oxides is in the range of from 3.5 to 995, preferably 8.8 to 198. At a weight ratio below 3.5, the fraction of solids in the composition is quite high, which may impede application of the composition by means of wet processing techniques. On the other hand, at a weight ratio above 995, the fraction of the carrier liquid, which has to be removed in the process of forming a composite layer, is relatively large, and processing may become inefficient.

A composite layer as defined above arranged on a surface of a solid substrate is obtainable by a process comprising the steps of

forming on a surface of said solid substrate a wet film by applying a composition according to the first aspect of the present invention to said surface of said solid substrate

removing said carrier liquid (c) of said composition from the wet film formed on said surface of said solid substrate

polymerizing the polymerizable moieties (d) on said surface of said solid substrate.

Particularly preferably, the composition applied to said surface of said solid substrate com- prises

(d) one or more polymerizable moieties,

and

(e) one or more initiators for initiating radical polymerization of said polymerizable moieties. Polymerization of the polymerizable moieties is preferably initiated by irradiation, especially irradiation having a wavelength in the range of from 360 nm to 420 nm, in the presence of an initiator which decomposes into radicals when exposed to said irradiation. Suitable initiators are known in the art and are commercially available.

In certain cases, preparing said process further comprises the step of annealing the layer formed on the surface of the solid substrate after polymerizing the polymerizable monomers.

Said solid substrate comprises, preferably consists of, one or more materials selected from the group consisting of glasses, metals, transparent conducting oxides and organic polymers. In some cases, the surface of the solid substrate to which the composition according to the invention is applied comprises an electronically conductive material, preferably an optically transparent electronically conductive material. Preferred optically transparent conducting materials are transparent conducting oxides (TCO), preferably selected from the group consisting of ITO (indium doped tin oxide), AZO (aluminum doped zinc oxide), IGZO (indium gallium doped zinc oxide), GZO (gallium doped zinc oxide), FTO (fluorine doped tin oxide), indium oxide, tin oxide and zinc oxide. In some cases, the surface of the solid substrate layer upon which the composite layer is arranged comprises one or more metallic electronically conductive materials, wherein the metals are preferably selected from the group consisting of Cu, Ag, Au, Pt and Pd. Preferably, the metal at the solid substrate surface is present in the form of a structure which is optically transparent, e.g. in the form of fine mesh or nanowires.

However, it has been found that in cases where the composition comprises electroconduc- tive nanoobjects (h) as defined above the electronic in-plane conductivity of a composite layer prepared from a composition according to the invention is sufficiently high so that providing the solid substrate surface with an electronically conductive material can be omitted.

Said solid substrate is preferably in a form selected from the group consisting of foils, films, webs, panes and plates. In certain cases, said solid substrate comprises an organic polymer and has a thickness in the range of from 10 μιτι to 200 μιτι, preferably from 50 μιτι to 150 μιτι.

In other cases, said solid substrate comprises glass and has a thickness in the range from 3 to 7 mm, preferably 4 to 6 mm, or in the range from 0.5 to 2.5 mm, preferably 0.7 to 2 mm. Preferred types of glass are e.g. float glass, low iron float glass, heat strengthened glass and chemically strengthened glass. Optionally, the glass has a low-emissivity (low-e) coating, sun-protection coating or any other coating on the surface facing away from the above- described composite layer.

Preferred organic polymers are selected from the group consisting of polymethylmethacry- late (PMMA, commercially available e.g. as Plexiglas™), polycarbonate (PC), polyethylene (PE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene (PP), low density polypropylene (LDPP), polyethylene therephthalate (PET), glycol modified polyethylene therephthalate, polyethylene naphthalate (PEN), cellulose acetate butyrate, polylactide (PL), polystyrene (PS), polyvinyl chloride (PVC), polyimides (PI), pol- ypropyleneoxide (PPO) and mixtures thereof. PET and PEN are particularly preferred.

Preferably, said solid substrate has a light transmission of 80 % or more measured according to ASTM D1003 (Procedure A) as published in November 2013.

Preferably, the composition which in the process according to the invention is applied to said surface of said solid substrate is selected from the above-defined preferred composi- tions according to the first aspect of the present invention. Preferably, the composition according to the present invention is applied to the surface of said solid substrate by coating or printing, preferably by a coating technique selected from the group consisting of roll-to- roll-, roll-to-sheet-, sheet-to-sheet-, slot-die-, spray-, ultrasonic spray-, dip- and blade coating, or by a printing technique selected from the group consisting of ink-jet-, pad-, offset-, gravure-, screen-, intaglio- and sheet-to-sheet- printing.

Preferably, the wet film formed by applying the composition according to the present invention to said surface of said solid substrate has a thickness in a range of from 1 μητι to 250 μητι, preferably of from 20 μιτι to 150 μιτι. Said thickness is also referred to as "wet thickness". In the above-defined process according to the present invention, the carrier liquid which has a boiling point below 120 °C is removed from said wet film on said surface of said solid substrate by exposing said wet film to a temperature in the range of from 20 °C to 120 °C, preferably 40 °C to 120 °C, most preferably 80 °C to 120 °C, to allow the carrier liquid to evaporate or volatilize. The step of polymerizing the polymerizable moieties on said surface of said solid substrate is performed after the step of removing said carrier liquid having a boiling point below 120 °C from the wet film formed on said surface of said solid substrate. In certain cases, in the step of polymerizing the polymerizable moieties the degree of conversation of the double bonds in the polymerizable moieties is significantly below 96 %, preferably 90 % or less, further preferably 80 % or less, more preferably 70 % or less, particularly preferably 60 % or less, or 50 % or less, and polymerization is completed in a later stage e.g. when the surface of the composite layer facing away from the solid substrate is to be bonded to another layer (see below).

In certain cases, after polymerization of said polymerizable moieties on the surface of said solid substrate, a sequence comprising the steps of

forming a wet film by applying the above-defined composition according to the invention on the surface of the layer wherein the polymerizable moieties have been polymerized,

removing said carrier liquid (c) of said composition from the wet film,

polymerizing said polymerizable moieties in the layer,

optionally annealing the layer after polymerizing the polymerizable monomers is carried out and optionally repeated at least once.

Preferably, in a process for preparing a composite layer as defined above, the following constituents of the composition according to the first aspect of the present invention are applied to the surface of said solid substrate in the following amount per cm² of said surface:

(a) nanoobjects comprising one or more electrochromic oxides as defined above in an amount of 0.05 mg/cm² to 6 mg/cm²

(d) polymerizable moieties in an amount of 0.0007 mg/cm² to 13.3 mg/cm²

(f) optionally polymers in an amount of 0.0007 mg/cm² to 13.3 mg/cm²

(g) the aprotic organic liquid having a boiling point of 120 °C or higher in an amount of 0.0001 mg/cm² to 2.05 mg/cm²

(h) optionally electronically conductive nanoobjects not comprising any oxides of nickel in an amount of 0.0009 mg/cm² to 6 mg/cm².

When said polymerizable moieties are co-polymerizable monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates, said monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates are applied in an amount of 0.0006 mg/cm² to 10.9 mg/cm² and said monomers selected from the group of hydroxyalkyl acrylates and hydroxyalkyl methacrylates in an amount of 0.0001 mg cm² to 2.4 mg /cm².

In a second aspect, the present invention relates to an article for production of or use in an electrochromic device and methods for preparing such articles. The term "electrochromic device" as used herein refers to a device exploiting the electrochromic effect as defined above. Such device comprises at least one electrode comprising an electrochromic material, a counter electrode and a separator layer sandwiched between and electronically separating said electrodes. Electrochromic devices are used, inter alia, as fagade and roof elements, interior construction and design elements for buildings and vehicles, displays, visualization optics and electrochromic mirrors. A widely known type of electrochromic devices are so-called smart windows. The term "smart windows" is known in the art.

An article according to the second aspect of the present invention comprises or consists of (A-1 ) a substrate,

(A-2) a composite layer arranged on a surface of said substrate (A-1 ), said composite layer (A-2) comprising

a matrix formed of one or more organic polymers and

and dispersed within said matrix:

(b) optionally one or more metal salts according to formula (I)

(g) an aprotic organic liquid having a boiling point of 120 °C or higher wherein in said composite layer (A-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less

and

(B-1 ) a separator layer arranged on a surface of said composite layer (A-2) facing away from said substrate (A-1 ),

said separator layer (B-1 ) comprising

a matrix formed of one or more organic polymers

and dispersed within said matrix

(g") an aprotic organic liquid having a boiling point of 120 °C or higher.

As used herein, "ppm" means "part per million" with respect to the total weight of the composite layer (A-2). Preferably, said solid substrate (A-1 ) comprises one or more materials selected from the group consisting of glasses, metals, transparent conducting oxides and organic polymers. Said solid substrate is preferably in a form selected from the group consisting of foils, films, webs, panes and plates. Preferably said solid substrate is optically transparent, i.e. exhibits a light transmission of 80 % or more measured according to DIN EN 410. Regarding further specific and preferred features of the solid substrate, reference is made to the disclosure provided above.

The composite layer (A-2) arranged on the surface of the solid substrate (A-1 ) has thickness in the range of from 0.05 μιτι to 500 μιτι, preferably 0.05 μιτι to 50 μιτι, most preferably 0.1 μιτι to 30 μιτι.

Said separator layer (B-1 ) is virtually electronically insulating, but allows for flow of ions. Without being bound to theory, it is believed that in the separator layer (B-1 ) said aprotic organic liquid (g") as defined above is confined within pores extending through the matrix thus providing a network for the transport of ions. In said separator layer (B-1 ), preferably the matrix is formed of the same organic polymers as the matrix in the composite layer (A-2), and the aprotic organic liquid (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the first composite layer.

Said separator layer preferably has a thickness in the range of from 0.05 μιτι to 1500 μιτι, preferably 0.05 μιτι to 1000 μιτι, most preferably 1 μητι to 800 μιτι. Thickness may be determined by profilometry, atomic force microscopy or electron microscopy.

An article as defined above is obtainable by a process comprising the steps of

preparing a composite layer (A-2) as defined above on a surface of a solid substrate (A-1 ) by a process as described above, and

- disposing a separator layer (B-1 ) as defined above on the surface of said composite layer (A-2) facing away from the solid substrate.

Disposing a separator layer (B-1 ) on the surface of said composite layer (A-2) facing away from said first solid substrate (A-1 ) comprises the steps of

forming on said surface of said composite layer a wet film by applying to said surface a composition (B-0) comprising (c") optionally a carrier liquid having a boiling point below 120 °C

(d") one or more kinds of polymerizable moieties,

(e") optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties

(g") an aprotic organic liquid having a boiling point of 120 °C or higher

(i") optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺,

in case the composition contains a carrier liquid (c") having a boiling point below 120 °C, removing the carrier liquid having a boiling point below 120 °C from the wet film formed on the surface of said composite layer

polymerizing the polymerizable moieties in the layer formed on the surface of said composite layer.

In certain cases, said composition (B-0) for preparing the separator layer comprises a carrier liquid (c"). However, in said composition for disposing a separator layer as defined above advantageously a carrier liquid as a vehicle for wet processing can be omitted, because said composition does not comprise non-dissolved matter, in contrast to the above- described composition for preparing a composite layer or a precursor layer thereof. Accordingly, the step of removing the carrier liquid from the wet film can be omitted in preparing the separator layer.

Preferably, in a composition (B-0)

(c") the total amount of said carrier liquid is 0 wt.-%

(d") the total amount of polymerizable moieties is in the range of from 65 wt.-% to 94 wt.-

%,

(e") the total amount of said initiators is in the range of from 0.1 wt.-% to 5 wt.-%,

(g") the amount of said aprotic organic liquid having a boiling point of 120 °C or higher is in the range of from 5 wt.-% to 20 wt.-%

in each case based on the total weight of the composition (B-0). In certain cases (see below), said composition (B-0) further comprises

(i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺, wherein in said composition (B-0) the total concentration of said electrolytes is in the range of from 0.5 wt.-% to 15 wt.-%, based on the total weight of said composition.

Regarding preferred and specific carrier liquids (c"), polymerizable moieties (d"), initiators (e"), and aprotic organic liquids (g") having a boiling point of 120 °C or higher, the same applies as disclosed above in the context of the first aspect of the present invention for the carrier liquid (c), polymerizable moieties (d), initiators (e) and aprotic organic liquid (g) hav- ing a boiling point of 120 °C or higher, resp., of the composition according to the first aspect of the present invention.

In the composition for preparing the separator layer, preferably the polymerizable moieties (d") are the same as the polymerizable moieties (d) in the composition for preparing the composite layer, and the aprotic organic liquid (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the composition for preparing the composite layer.

If said composition for preparing the separator layer comprises a carrier liquid, the step of polymerizing the polymerizable moieties is performed after the step of removing said carrier liquid having a boiling point below 120 °C from the wet film formed on said surface of said solid substrate.

In certain cases, in the step of polymerizing the polymerizable moieties the degree of conversation of the double bonds in the polymerizable moieties is significantly below 96 %, preferably 90 % or less, further preferably 80 % or less, more preferably 70 % or less, particularly preferably 60 % or less, or 50 % or less, and polymerization is completed during bonding the surface of the separator layer facing away from the composite layer to another layer.

In certain cases, after polymerization of said polymerizable moieties on the surface of said composite layer, a sequence comprising the steps of

forming a wet film by applying the above-defined composition on the surface of the layer wherein the polymerizable moieties have been polymerized, in case the composition contains a carrier liquid (c"), removing from said wet film said carrier liquid having a boiling point below 120 °C,

polymerizing said polymerizable moieties in the layer,

is carried out and optionally repeated at least once. Preferably, the composition for preparing the separator layer is applied to the surface of said composite layer by coating or printing, preferably by a coating technique selected from the group consisting of roll-to-roll-, roll-to-sheet-, sheet-to-sheet-, slot-die-, spray-, ultrasonic spray-, dip- and blade coating, or by a printing technique selected from the group consisting of ink-jet-, pad-, offset-, gravure-, screen-, intaglio- and sheet-to-sheet- printing. In the above-defined process for disposing the separator layer, the carrier liquid (c") - if present - is removed from said wet film on said surface of said solid substrate by exposing said wet film to a temperature in the range of from 20 °C to 120 °C, preferably 40 °C to 120 °C, most preferably 80 °C to 120 °C.

Preferably, the composition for preparing the separator layer does not contain a carrier liquid (c"), and the wet film formed by applying the composition for preparing the separator layer to said surface of said composite layer has a thickness in a range of from 0.05 μιτι to 1500 μιτι, preferably of from 0.05 μιτι to 1000 μιτι. Said thickness is also referred to as "wet thickness".

For further details of disposing a separator layer on the surface of an above-defined com- posite layer facing away from said first solid substrate, see the non-prepublished patent application having the application number PCT/EP2017/055320.

The above-defined article is suitable for preparing a multilayer structure for production of or use in an electrochromic device by combining said article with a counter electrode as described below. Said counter electrode is a second composite layer (C-2) arranged on a surface of said substrate (C-1 ), said second composite layer (C-2) comprising

a matrix formed of one or more organic polymers

and dispersed within said matrix:

(a') nanoobjects comprising one or more electrochromic oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon, which are different from the electrochromic oxides comprised by the nanoobjects (a) of the first composite layer (A-2)

(b') optionally one or more metal salts according to formula (I)

(g') an aprotic organic liquid having a boiling point of 120 °C or higher.

Said second composite layer (C-2) arranged on a surface of said second solid substrate (C-1 ) is obtainable by a process as described above in the context of the first aspect of the present invention. For preparing the second composite layer (C-2) a composition (C-0) is used, said composition (C-0) comprising

(a') nanoobjects comprising one or more electrochromic oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon which are different from the electrochromic oxides comprised by the nanoobjects (a) of the composition (A-0) used for preparing the first composite layer (A-2)

(b') optionally a metal salt according to formula (I) as defined above

(c') a carrier liquid having a boiling point below 120 °C

(d') one or more kinds of polymerizable moieties

(e') optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties

(g') an aprotic organic liquid having a boiling point of 120 °C or higher

(h') optionally electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14.

In certain preferred articles (as defined above) said separator layer (B-1 ) further comprises

(i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g"),

wherein in the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layer (B-1 ) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

Typically, in said separator layer the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is more than 100 ppm, preferably more than 200 ppm, further preferably more than 1000 ppm.

As used herein, "ppm" means "part per million" with respect to the total weight of the separator layer (B-1 ).

The term "electrolyte" is known in the art and denotes a substance which is capable of dissociating into mobile ions. For specific and preferred electrolytes (i"), see below. Such preferred article is suitable for combination with a second composite layer (C-2) as defined above as the counter electrode, when in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less. As used herein, "ppm" means "part per million" with respect to the total weight of the second composite layer (C-2).

Thus, advantageously said second composite layer (C-2) is obtainable in the same way as the first composite layer, from an ink having a total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ of 2 ppm or less, preferably 0.02 ppm or less, most preferably 0.002 ppm or less. Ions from the electrolyte (i") which is present in said separator layer may enter the first and second composite layer (C-2) which have a significantly lower concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ by diffusion and migration, thereby providing for sufficient ionic conductivity in the first and second composite layer.

Such preferred article is (as defined above) also suitable for combination with a counter electrode which is not a second composite layer (C-2) as defined above. For instance, the counter electrode layer is obtained by depositing an electroactive material on the surface of said second solid substrate. Depositing the electroactive material (e.g. an electrochromic material) may be achieved by means of sputtering. Said counter electrode layer may comprise an electroactive material which independent from its state of oxidation is substantially optically transparent or has an electrochromic effect involving a color change significantly less pronounced than that of the electrochromic metal oxide in the nanoobjects (a) of the electrochromic composite layer. Suitable electroactive materials are known in the art and include, but are not limited to tin oxide, cerium oxide, and transparent polymers capable of intercalating lithium ions. Alternatively, said counter electrode layer comprises an electro- active material which exhibits an electrochromic effect having a dependence on the applied electrochemical potential which is opposite to the electrochromic effect of the electrochromic metal oxide in the electrochromic composite layer. For instance, the electrochromic oxide of the electrochromic composite layer colors during anodic oxidation and discolors during cathodic reduction, and the electrochromic material in the counter electrode colors during cathodic reduction and discolors during anodic oxidation, or vice versa. Alternatively, the electrochromic oxide of the electrochromic composite layer adopts a dark color during anodic oxidation and a less dark color during cathodic reduction, and the electrochromic material in the counter electrode adopts a dark color during cathodic reduction and a less dark color during anodic oxidation, or vice versa.

Alternatively, in said separator layer (B-1 ) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 20 ppm or less, preferably 4 ppm or less, most preferably 0.4 ppm or less. Such article is suitable for combination with a second composite layer (C-2) as the counter electrode, when said second composite layer (C-2) comprises (i') at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g') wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said second composite layer (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layer and said first composite layer by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more. Typically, in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is more than 100 ppm, preferably more than 200 ppm, most preferably more than 1000 ppm. Ions from the electrolyte (i") which is present in said second composite layer may enter the separator layer and the first composite layer which have a significant lower concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ by diffu- sion and migration, thereby providing for sufficient ionic conductivity in the separator layer and the first composite layer.

A particularly preferred article according to the second aspect of the invention comprises a multilayer structure consisting of

(A-1 ) a first substrate, (A-2) a first composite layer as defined above arranged on a surface of said first substrate (A-1 ),

(C-1 ) a second solid substrate,

(C-2) a second composite layer arranged on a surface of said substrate (C-1 ), said second composite layer (C-2) comprising

a matrix formed of one or more organic polymers

and dispersed within said matrix:

(b') optionally one or more metal salts according to formula (I)

(g') an aprotic organic liquid having a boiling point of 120 °C or higher

(B) sandwiched between said first composite layer (A-2) and said second composite layer (C-2), a separator layer (B) comprising

a matrix formed of one or more organic polymers

and dispersed within said matrix

(g") an aprotic organic liquid having a boiling point of 120 °C or higher wherein at least one of said second composite layer (C-2) and said separator layer (B) further comprises

(i,' i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g', g")

wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said layers (B), (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in the first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

Said article comprises a multilayer structure which in the direction of stacking consists of a first solid substrate (A-1 ), a first composite layer (A-2) as defined above, a separator layer (B), a second composite layer (C-2) as defined above and a second solid substrate (C-1 ). In said article said separator layer (B) has a first surface and a second surface opposite to said first surface, wherein said first surface of said separator layer (B) is in contact with a surface of said first composite layer (A-2) facing away from said first solid substrate (A-1 ), and said second surface of said separator layer (B) is in contact with a surface of said second composite layer (C-2) facing away from said second solid substrate (C-1 ). Said solid substrates (A-1 ), (C-1 ) comprise one or more materials selected from the group consisting of glasses, metals and organic polymers. At least one of said solid substrates (A-1 ), (C-1 ) exhibits a light transmission of 80 % or more measured according to DIN EN 410.

The first composite layer (A-2) arranged on the surface of the solid substrate (A-1 ) has a thickness in the range of from 0.05 μιτι to 500 μιτι, preferably 0.05 μιτι to 50 μιτι, most preferably 0.1 μιτι to 30 μιτι. The second composite layer (C-2) arranged on the surface of the second solid substrate (C-1 ) has a thickness in the range of from 0.05 μιτι to 500 μιτι, preferably 0.05 μιτι to 50 μιτι, most preferably 0.1 μιτι to 30 μιτι.

Said separator layer (B) is virtually electronically insulating, but allows for flow of ions. With- out being bound to theory, it is believed that in the separator layer (B) said aprotic organic liquid (g") as defined above is confined within pores extending through the matrix thus providing a network for the transport of ions between the first and the second composite layer.

In said second composite layer (C-2) and said separator layer (B), preferably the matrix is formed of the same organic polymers as the matrix in the first composite layer and the aprotic organic liquid (g') resp. (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the first composite layer.

At least one of said separator layer (B) and said second composite layer (C-2) contains an electrolyte (i'), (i"), resp., wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said layers (B), (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in the first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more. It has been found that ions from the electrolyte which is present in said separator layer (B) or said second composite layer (C-2) may enter the other layer(s) having a significantly lower concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ by diffusion and migration, thereby providing for sufficient ionic conductivity across the respec- tive layers.

In the context of this disclosure, water does not belong to the electrolytes (Γ), (i") as defined above. Accordingly, said electrolyte comprises at least one anion which is different from OH^" or at least one cation from the group consisting of Li⁺, Na⁺ and K⁺.

Preferred electrolytes (¥), (i") are lithium salts. Preferably, said electrolytes (i'),(i") are selected from the group consisting of lithium aluminum chloride (LiAICU); lithium hexafluorosilicate (Li2SiFe); lithium hexafluoroantimonate (LiSbFe); LiX(RS0₂)n wherein n=1 and X=0 or S, n=2 and X=N or P, n=3 and X=C or Si, and R in each case is CmH2m+i-nF_n wherein m = 0-20, n = 0-21 ; lithium fluoride (LiF); lithium nitrate (L1NO3); lithium perchlorate (LiCIC ); lithium tetrafluoroborate (L1BF4); lithium tetrakis(pentafluorophenyl)borate; lithium difluorophosphate (L1PO2F2); lithium hexafluoro- phosphate (LiPFe); lithium hexafluoroarsenate (LiAsFe); lithium bis(fluorosulfonyl)imide (LiN(S0₂F)₂); lithium trifluoromethylsulfonate (UCF3SO3); LiN(S0₂CnF2n₊i )2 wherein n = 2 to 20; LiC[(CnF2n-i)S0₂]3 wherein n = 2 to 20; Li(CnF2n₊i)S0₂ wherein n = 2 to 20; lithium bis(trifluoromethane)sulfonimide (LiN(CF3S02)2, also referred to as lithium bis-trifluorome- thylsulfonylimide); lithium tris-trifluoromethyl sulfonylmethide (LiC(CF3S02)3); lithium bisox- alatoborate (LiB(C204)2); lithium difluoro(oxalate)borate (LiBF2(C204)); lithium difluoro(bi- soxalato)phosphate and lithium tetrafluoro(oxalate)phosphate.

Preferably, said electrolyte (i'), (i") has an anion which is selected from the group consisting of anions Z^b~ as defined above for the metal salts (b) of formula (I). Preferably, said electrolytes (¥), (i") are selected from the group consisting of lithium aluminum chloride (LiAICU); lithium hexafluoroantimonate (LiSbFe); LiX(RS02)n wherein n=1 and X=0 n=2 and X=N, n=3 and X=C , and R in each case is CmH2m+i-nF_n wherein m = 0- 20, n = 0-21 , lithium perchlorate (LiCIC ); lithium tetrakis(pentafluorophenyl)borate; (LiPFe); lithium hexafluoroarsenate (LiAsFe); lithium bis(fluorosulfonyl)imide (LiN(S02F)2); lithium trifluoromethylsulfonate (UCF3SO3); LiN(S02C_nF2n+i )2 wherein n = 2 to 20; LiC[(C_nF2n-i )S02]3 wherein n = 2 to 20; lithium bis(trifluoromethane)sulfonimide (LiN(CF₃S0₂)2); and lithium tris-trifluoromethyl sulfonylmethide (LiC(CF₃S0₂)3). Most preferably, said electrolyte (¥), (i") is selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sulfonimide and lithium bis(fluorosulfonyl)imide.

Said second composite layer functions as counter electrode with respect to the first composite layer in an electrochromic device. In said second composite layer, the nanoobjects (a') comprise electrochromic oxides which are different from the electrochromic oxides comprised by the nanoobjects (a) of the first composite layer. Preferably, the electrochromic oxides in the second composite layer are selected to exhibit an electrochromic effect having a dependence on the applied electrochemical potential which is opposite to the electrochromic effect of the electrochromic metal oxide in the first composite layer. For instance, the electrochromic oxide of the first composite layer colors during anodic oxidation and discolors during cathodic reduction, and the electrochromic material in the second composite layer colors during cathodic reduction and discolors during anodic oxidation, or vice versa. Alternatively, the electrochromic oxide of the first composite layer adopts a dark color during anodic oxidation and a less dark color during cathodic reduction, and the electrochromic material in the second composite layer adopts a dark color during cathodic reduction and a less dark color during anodic oxidation, or vice versa.

In a specific preferred case, the nanoobjects (a) of the first composite layer (A-2) comprise one or more oxides of nickel, and the nanoobjects (a') of the second composite layer (C-2) comprise one or more oxides of tungsten or vice versa.

Said second composite layer (C-2) arranged on a surface of said second solid substrate (C-1 ) is obtainable by a process as described above in the context of the first aspect of the present invention for preparing said first composite layer (A-2) arranged on a surface of said first solid substrate (A-1 ).

Optionally, said second composite layer (C-2) as defined above further comprises

(h') electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 dispersed within said matrix formed of one or more organic polymers.

In a first specifically preferred article comprising the above-defined multilayer structure said second composite layer (C-2) further comprises (ί') at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g'),

wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said second composite layer (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

Typically, in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is more than 100 ppm, preferably more than 200 ppm, further preferably more than 1000 ppm.

Regarding said first specifically preferred article, it is further preferred that in said separator layer (B) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 20 ppm or less, preferably 4 ppm or less, most preferably 0.4 ppm or less. Ions from the electrolyte which is present in said second composite layer (C-2) may enter the separator layer (B) and the first composite layer (A-2) which have a significantly lower concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ by diffusion and migration, thereby providing for sufficient ionic conductivity in the separator layer and the first composite layer.

In a second specifically preferred article comprising the above-defined multilayer structure, said separator layer (B) further comprises

(i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g")

wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layer (B) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

Typically, in said separator layer (B) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is more than 100 ppm, preferably more than 200 ppm, further preferably more than 1000 ppm. As used herein, "ppm" means "part per million" with respect to the total weight of the separator layer (B). Regarding said second specifically preferred article, it is further preferred that in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 2 ppm or less, preferably 0.02 ppm or less, most preferably 0.002 ppm or less.

Thus, in an especially preferred article comprising the above-defined multilayer structure, in said first composite layer (A-2) and in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less and said separator layer (B) comprises

(i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g") wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layer (B) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) as well as the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said second composite layer (C-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

Ions from the electrolyte which is present in said separator layer (B) may enter the first composite layer (A-2) and the second composite layer (C-2) which have a significantly lower concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ by diffusion and migration, thereby providing for sufficient ionic conductivity in the first and second composite layer.

An article comprising the above-defined multilayer structure for production of or use in an electrochromic device is obtainable by a process comprising the steps of

preparing

a first layer assembly (A) comprising a first solid substrate (A-1 ) having a surface and arranged on said surface of said first solid substrate a first composite layer (A-2) as defined above, and optionally a separator layer (B-1 ) as defined above disposed on a surface of said first composite layer (A-2) facing away from said first solid substrate (A-1 ) or a wet film obtained by applying the above-defined composition (B-0) on said surface of the first composite layer (A-2) facing away from said first solid substrate (A-1 ),

and

a second layer assembly (C) comprising a second solid substrate (C-1 ) having a surface and arranged on said surface of said second solid substrate a second composite layer (C-2) as defined above, and optionally a separator layer (B-2) as defined above disposed on a surface of said second composite layer (C-2) facing away from said second solid substrate (C-1 ) or a wet film obtained by applying the above-defined composition (B-0) on said surface of the second composite layer (C-2) facing away from said second solid substrate (C- 1 ),

with the proviso that

at least one of said first layer assembly (A) and said second layer assembly (C) comprises a separator layer (B-1 ), (B-2) or a wet film obtained by applying the above-defined composition (B-0)

and at least one of said second composite layer (C-2) and said separator layers (B-1 ), (B-2) resp. wet films obtained by applying the above-defined composition (B-0) further comprises

(i,' i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g', g"), wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layers (B-1 ), (B-2), resp. in said wet films, resp. in said layer (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in the first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more,

stacking and bonding said layer assemblies so that an article is obtained having a separator layer (B) sandwiched between said first composite layer (A-2) and said second composite layer (C-2).

Separator layer (B-2) on the surface of said second composite layer (C-2) is obtainable by a process as described above for obtaining a separator layer (B-1 ) on a surface of said first composite layer (A-2). Bonding may be achieved by polymerizing the monomers (d") in said wet film obtained by applying the above-defined composition (B-0) on the surface of the first resp. second composite layer as defined above, or by completing the polymerization of the polymerizable moieties (d), (d'), (d"), resp. in said layers to be bonded. For further details of the above-mentioned bonding, see the non-prepublished patent application having the application number PCT/EP2017/055320.

When the first layer assembly (A) comprises a separator layer (B-1 ) and the second layer assembly (C) does not comprise a separator layer, a bonding is achieved between the separator layer (B-1 ) of the first layer assembly and the second composite layer (C-2), and the obtained article comprises a separator layer (B-1 ) sandwiched between said first composite layer (A-2) and said second composite layer (C-2).

When the first layer assembly (A) does not comprises a separator layer and the second layer assembly (C) comprises a separator layer (B-2), a bonding is achieved between the first composite layer (A-2) and the separator layer (B-2) of the second layer assembly, and the obtained article comprises a separator layer (B-2) sandwiched between said first composite layer (A-2) and said second composite layer (C-2).

When the first layer assembly (A) comprises a separator layer (B-1 ) and the second layer assembly (C) comprises a separator layer (B-2), a bonding is achieved between the separator layer (B-1 ) of the first layer assembly and the separator layer (B-2) of the second layer assembly, and the obtained article comprises a resulting separator layer (B-1/B-2) sandwiched between said first composite layer (A-2) and said second composite layer (C-2).

Irrespective of their origin from the first layer assembly (A), the second layer assembly (C) or from both, the separator layers (B-1 ), (B-2), (B-1/B-2) are herein commonly referred to as "separator layer (B)" where appropriate. Said first composite layer (A-2) arranged on a surface of said first solid substrate (A-1 ) and said second composite layer (C-2) arranged on a surface of said second solid substrate (C-1 ) are obtainable by a process as described above in the context of the first aspect of the present invention. For preparing the first composite layer (A-2) a composition (A-0) according to the first aspect of the present invention is used. For preparing the second composite layer (C-2) a composition (C-0) is used as defined above which comprises

(b') optionally a metal salt according to formula (I) as defined above

(c') a carrier liquid having a boiling point below 120 °C

(d') one or more kinds of polymerizable moieties

(g') an aprotic organic liquid having a boiling point of 120 °C or higher

In said ink (C-0) the nanoobjects (a') comprise electrochromic oxides which are different from the electrochromic oxides comprised by the nanoobjects (a) of the first composite layer. As regards criteria for selecting said electrochromic material, see above. In a specific preferred case, the nanoobjects (a) of the composition (A-0) comprise one or more oxides of nickel, and the nanoobjects (a') of the composition (C-0) comprise one or more oxides of tungsten, or vice versa.

Regarding preferred and specific metal salts (b'), carrier liquids (c'), polymerizable moieties (d'), initiators (e'), polymers (f) aprotic organic liquids (g') having a boiling point of 120 °C or higher and electroconductive nanoobjects (h') of the composition (C-0), the same applies as disclosed above in the context of the first aspect of the present invention for the metal salts (b), carrier liquid (c), polymerizable moieties (d), initiators (e), aprotic organic liquid

(g) having a boiling point of 120 °C or higher, and electroconductive nanoobjects (h) resp., of the composition (A-0) according to the first aspect of the present invention. In the composition (C-0) for preparing the second composite layer (C-2), preferably the polymerizable moieties (d') are the same as the polymerizable moieties (d) in the composition (A-0) for preparing the first composite layer (A-2), and the aprotic organic liquid (g') having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the composition (A-0) for preparing the first composite layer (A-2).

For preparing the separator layer (B) a composition (B-0) as defined above is used.

At least one of said compositions (B-0) and (C-0) comprises

(i,' i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺

in an amount suitable for preparing a layer having a total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said layers (B), (C-2) which exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in the first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

In a first specifically preferred process, said composition (C-0) comprises

(i') at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ wherein in said composition the total concentration of said electrolytes is preferably in the range of from 0.001 wt.-% to 0.4 wt.-%. Regarding said first specifically preferred process, it is further preferred that in the composition (B-0) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 20 ppm or less, preferably 4 ppm or less, most preferably 0.4 ppm or less and said composition (B-0) does not comprise a carrier liquid.

By using these compositions (B-0) and (C-0) and the composition (A-0) as defined above in the context of the first aspect of the present invention in the above-defined first specifically preferred process, an article is obtainable wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said second composite layer (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) as well as in said separator layer (B) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more. Typically, in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is more than 100 ppm, preferably more than 200 ppm, most preferably more than 1000 ppm, and in said separator layer (B) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 20 ppm or less, preferably 4 ppm or less, most preferably 0.4 ppm or less.

In a second specifically preferred process, said composition (B-0) comprises

(i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺, wherein in said composition (B-0) the total concentration of said electrolytes is in the range of from 0.5 wt.-% to 15 wt.-%, based on the total weight of said composition

and no carrier liquid (c").

Regarding said second specifically preferred process, it is further preferred that in the composition (C-0) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 2 ppm or less, preferably 0.02 ppm or less, most preferably 0.002 ppm or less. This is advantageous, because composition (C-0) comprises nanoobjects (a'), and high concentrations of electrolytes having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ have a detrimental influence on the stability of suspended nanoobjects against agglomeration and settling have a detrimental influence on the stability of suspended nanoobjects against agglomeration and settling. On the other hand, the composi- tion (B-0) does not comprise any suspended nanoobjects, therefore the presence of significant concentrations of electrolytes having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is not disadvantageous.

By using these compositions (B-0) and (C-0) and the composition (A-0) as defined above in the context of the first aspect of the present invention in the above-defined second spe- cifically preferred process, an article is obtainable, wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layer (B) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) as well as in said second composite layer (C-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

Typically, in said separator layer (B) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is more than 100 ppm, preferably more than 200 ppm, most preferably more than 1000 ppm, and in said second composite layer (C-2) total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 20 ppm or less, preferably 4 ppm or less, most preferably 0.4 ppm or less.

According to a third aspect, there is provided a method for preconditioning a multilayer structure for production of or use in an electrochromic device, said process comprising the steps of:

providing an article comprising a multilayer structure as defined above

applying an electric voltage between the first and the second composite layer to allow migration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ across the separator layer to the first composite layer. According to a fourth aspect the present invention relates to the use of an article comprising a multilayer structure as defined above for production of or use in an electrochromic device.

In certain cases, an article for production of or use in an electrochromic device further comprises a support layer attached to the surface of the first solid substrate facing away from the composite layer and/or a support layer attached to the surface of the second solid sub- strate facing away from said counter electrode layer. Preferably, a first support layer is attached to the surface of the first solid substrate facing away from the composite layer and a second support layer is attached to the surface of the second solid substrate facing away from said counter electrode layer. In this regard, it is particularly preferred that the first and second solid substrate comprise materials from the group of organic polymers and are in the form of foils, films, webs, and the first and second support layer comprise glass.

Furthermore, a third support layer may be attached to the surface of the first support layer facing away from the first solid substrate and/or a fourth support layer may be attached to the surface of the second support layer facing away from the second solid substrate. In this regard it is particularly preferred that a third support layer is attached to the surface of the first support layer facing away from the first solid substrate and a fourth support layer is attached to the surface of the second support layer facing away from the second solid substrate. In this regard, it is particularly preferred that the first, second, third and fourth support layer comprise glass.

Said support layers comprise one or more materials selected from the group consisting of glasses, metals and organic polymers. Preferred types of glass are e.g. float glass, low iron float glass, heat strengthened glass and chemically strengthened glass. Optionally, the glass has a low-emissivity (low-e) coating, sun-protection coating or any other coating on the surface facing outwardly.

Attaching said first resp. second support layer to said first resp. second solid substrate preferably comprises applying an adhesive between the support layer and the surface of the solid substrate to which said support layer has to be attached. Attaching said third resp. fourth support layer to said first resp. second support layer preferably comprises applying an adhesive. Suitable adhesives are thermoplastics, e.g. polyvinylbutyral, polyvinylalcohol, polyvinylacetate, ethylene-vinylacetate-copolymers, polyurethanes, ionomer resins (commercially available e.g. under the trade name SentryGlas®) and polymethylmethacrylate (PMMA).

The present invention further relates to the use of an article as defined above resp., an electrochromic device as defined above in buildings, furniture, cars, trains, planes and ships as well as to the in facades, skylights, glass roofs, stair treads, glass bridges, canopies, railings, car glazing, train glazing. The present invention further relates to insulating glass units, windows, rotating windows, turn windows, tilt windows, top-hung windows, swinging windows, box windows, horizontal sliding windows, vertical sliding windows, quarterlights, store windows, skylights, light domes, doors, horizontal sliding doors in double-skin facades, closed cavity facades, all- glass constructions, D3-facades (Dual, Dynamic Durable Facade), facade glass construc- tion elements (e.g. but not limited to fins, louvres), interactive facades (facades reacting on an external impulse e.g. but not limited to a motion control, a radio sensor, other sensors) curved glazing, formed glazing, 3D three-dimensional glazing, wood-glass combinations, over head glazing, roof glazing, bus stops, shower wall, indoor walls, indoor separating elements in open space offices and rooms, outdoor walls, stair treads, glass bridges, can- opies, railings, aquaria, balconies, privacy glass and figured glass.

The present invention further relates to thermal insulation, i.e. insulation against heat, insulation against cold, sound insulation, shading and/or sight protection. The present invention is preferably useful when combined with further glass layers to an insulation glass unit (IGU), which can be used for building facades. The IGU might have a double (Pane 1 + Pane 2), or triple glazing (Pane 1 + Pane 2 + Pane 3), or more panes. The panes might have different thicknesses and different sizes. The panes might be of tempered glass, tempered safety glass, laminated glass, laminated tempered glass, safety glass. The device according to the present application may be used in any of the panes 1 , 2, 3. Materials can be put into the space between the panes. For example, but not limited such materials might be argon, xenon, nitrogen, wooden objects, metal objects, expanded metal, prismatic objects, blinds, louvres, light guiding objects, light guiding films, light guiding blinds, 3-D light guiding objects, sun protecting blinds, movable blinds, roller blinds, roller blinds from films, translucent materials, capillary objects, honey comb objects, micro blinds, micro lamella, micro shade, micro mirrors insulation materials, aerogel, integrated vacuum insulation panels, holographic elements, integrated photovoltaics or combinations thereof.

The present invention further relates to the use in heat-mirror glazing, vacuum glazing, multiple glazing and laminated safety glass.

The present invention further relates to the use in transportation units, preferably in boats, in vessels, in spacecrafts, in aircrafts, in helicopters, in trains, in automotive, in trucks, in cars e.g. but not limited to windows, separating walls, light surfaces and background lighting, signage, pass protection, as sunroof.

The present invention is preferentially useful when combined with further glass layers to an insulation glass unit (IGU), which can be used for building facades.

Examples

The invention is now further illustrated by means of a non-limiting example.

All compositions were obtained according to the examples disclosed in WO 2016/128133. The nanoparticles were either commercially available or obtained by flame spray pyrolysis. All other constituents were all commercially available.

Composition (A-0) for preparing a first composite layer (A-2)

A composition (A-0) comprising

(a) nanoparticles comprising tungsten oxide

(c) a mixture consisting of water and 2-propanol

(d) a monomer selected from the group consisting of alkyl acrylates and alkyl meth- acrylates and a monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates

(e) an initiator for initiating copolymerization of monomers (d) by UV irradiation (g) 1 ,2-propylene carbonate was prepared. The concentrations of all constituents were in the above-defined preferred ranges.

Composition (C-0) for preparing a second composite layer (C-2)

A composition (C-0) comprising

(a') nanoparticles comprising nickel oxide

(c') ethanol

(d') a monomer selected from the group consisting of alkyl acrylates and alkyl meth- acrylates and a monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates

(e') an initiator for initiating copolymerization of monomers (d) by UV irradiation

(g') 1 ,2-propylene carbonate

was prepared. The concentrations of all constituents were in the above-defined preferred ranges

No electrolytes comprising cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ have been used in preparing said compositions (A-0) and (C-0). In composition (A-0) as well as in composition (C-0) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is less than 2 ppm.

Composition (B-0) for preparing the separation layer

A composition (B-0) comprising

(d") a monomer selected from the group consisting of alkyl acrylates and alkyl methacrylates and a monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates

(e") an initiator for initiating copolymerization of monomers (d) by UV irradiation

(g") 1 ,2-propylene carbonate

(i") lithium bis(trifluoromethane)sulfonimide

was prepared. The composition (B-0) did not comprise a carrier liguid having a boiling point below 120 °C. The concentrations of all constituents were in the above-defined preferred ranges. The monomers (d), (d'), (d") in composition (A-0), (C-0) and (B-0) are identical. Preparation of the composite layer (A-2), (C-2)

The composition (A-0) was used as ink for preparing a first composite layer (A-2) compris- ing the above-defined nanoparticles (a) on a first substrate (A-1 ).

The composition (C-0) was used as ink for preparing a second composite layer (C-2) comprising the above-defined nanoparticles (a') on a second substrate (C-1 ).

The substrate (A-1 ), (C-1 ) was in each case a PET foil having a surface coated with indium- tin-oxide (ITO). A wet film was formed in each case by blade-coating the ink on said ITO- coated surface. After evaporation of the carrier liquid (c), (c") at ambient conditions the monomers (d), (d') were copolymerized. The copolymerization was initiated by means of UV irradiation. Thereafter, the coated substrates were heated on a hot plate.

Preparation of a multilayer structure for preparation of or use in an electrochromic device

On the surface of the first composite layer (A-2) facing away from substrate (A-1 ) a wet film was formed by dropwise application of composition (B-0) by means of a syringe. The layer assembly consisting of the second substrate (C-1 ) and the second composite layer (C-2) arranged on the surface of said second substrate (C-1 ) was put on top of the wet film so that the wet film faces the composite layer (C-2).

The thus-obtained multilayer structure with the wet film of composition (B-0) sandwiched between the first composite layer (A-2) and the second composite layer (C-2) was exposed to UV irradiation using a mercury UV lamp for 60 s for polymerizing the monomers (d") in the wet film, thereby forming a separator layer (B) sandwiched between the first composite layer (A-2) and the second composite layer (C-2). Thus, a multilayer structure which in the direction of stacking consists of a first solid substrate (A-1 ), a first composite layer (A-2) as defined above, a separator layer (B), a second composite layer (C-2) as defined above and a second solid substrate (C-1 ) is obtained. Spectroelectrochemical studies of the multilayer structure

The electrochromic behavior of the multilayer structure obtained as described above was studied by means of multiple cycle cyclovoltammetry in a two-electrode configuration (working electrode: composite layer (A-2), counter and reference electrode: composite layer (C-2)).

The first five cycles (preconditioning phase, scan rate was 5 mV/s in each case) were carried out using the following voltage ranges:

1st CV cycle: -0.5V to 1.2V

2nd CV cycle: -1.2V to 1.2V

3rd CV cycle: -1.7V to 1.2V

4th CV cycle: -1.8V to 1.4V

5th CV cycle: -2.2V to 2.4V

Afterwards the electrochromic device was repeatedly switched for another 288 cycles (working phase, cycles 6-293) within the voltage range of -1.6 / +2.6 V at a scan rate of 10 mV/s. The color change was simultaneously monitored by in-situ UV-Vis measurements which prove a stable coloring and discoloring of the electrochromic device.

During the five cycles of the preconditioning phase, the shape of the cyclic voltammog rams changed due to development of anodic and cathodic peaks which significantly grew from the first to the fifth cycle, see figures 1 to 5. This is an evidence of increasing anodic oxida- tion/cathodic reduction of the electrochromic nanoparticles (a) in the first composite layer (A-2), which is facilitated by increasing diffusion and migration of Li⁺ cations from the electrolyte (i") present in the separator layer (B) into the first composite layer (A-2) for the balance of the reduction of the oxidation state of the tungsten in the tungsten oxide nanoparticles (a) during the cathodic scans. During the working phase, the cyclic voltammogram did not change as significantly as in the preconditioning phase, see figure 6. Accordingly, a virtually reproducible electrochromic behavior was achieved, as also evidenced by the reproducible optical modulation at fixed wavelength of 550 nm during the working phase, i.e. voltammetric cycles 6 to 293 (see figure 7).

Claims

Composition (A-0) comprising

(c) a carrier liquid having a boiling point below 120 °C

(d) one or more kinds of polymerizable moieties

(g) an aprotic organic liquid having a boiling point of 120 °C or higher

wherein in said composition (A-0) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 2 ppm or less, preferably 0.02 ppm or less, most preferably 0.002 ppm or less with respect to the total weight of the composition.

Composition according to claim 1 , further comprising

(e) one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties

and/or

(f) one or more organic polymers

and/or

(h) electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14.

Composition according to claim 1 or 2, wherein

(a) said nanoobjects are selected from the group consisting of nanowires and na- noparticles

and/or

(c) said carrier liquid having a boiling point below 120 °C is selected from the group consisting of alcohols, amines, carbonic acids, esters, ketones, organic carbonates, polyethers, sulfides and nitriles and mixtures thereof and/or (d) said polymerizable moieties are selected from the group consisting of alkyl acrylates, alkyl methacrylates, hydroxyalkyl acrylates, hydroxyalkyl methacry- lates, vinyl chloride, vinyl fluoride, acrylonitrile, vinylidene fluoride, vinylidene chloride, hexafluoropropylene, trifluoroethylene, tetrafluoroethylene, tetrahy- drofuran, vinylpyrrolidone, polyisocyanates in combination with polyols and/or diamines

and/or

(f) said organic polymers are selected from the group consisting of polyalkyl acrylates, polyalkyl methacrylates, polyhydroxyalkyl acrylates, poly- hydroxyalkyl methacrylates, polyvinyl chloride, polyvinyl fluoride, polyacrylo- nitrile, polyvinylidene fluoride, polyvinylidene chloride, polyhexafluoropropyl- ene, polytrifluorethylene, polytetrafluoroethylene, polytetrahydrofuran, polyvinylpyrrolidone, polyurethanes, polyethylene oxide

and/or

(g) said non-polymerizable aprotic organic liquid having a boiling point of 120 °C or higher is selected from the group consisting of organic carbonates, alco- holes, amides, carboxylic acid esters, ethers, polyethers, ketones, lactones, lactames, phosphoric acid esters, sulfones, sulfoxides, sulfonates and urea derivatives and mixtures thereof

and/or

(h) said nanoobjects are nanowires comprising materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel.

Composition according to any of claims 1 to 3, comprising

(a) nanoparticles comprising one or more oxides of tungsten or nanoparticles comprising one or more oxides of nickel

(c) a carrier liquid selected from the group consisting of ethanol, methanol, 2- propanol, 2-methyl tetrahydrofuran and mixtures thereof

(d) one or more kinds of monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and one or more kinds of monomers selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates (e) an initiator which decomposes into radicals when exposed to irradiation

(g) an aprotic organic liquid selected from the group consisting of ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3-propylene carbonate and mixtures thereof

(h) optionally silver nanowires.

An article comprising

(A-1 ) a substrate,

(A-2) a composite layer arranged on a surface of said substrate (A-1 ), said composite layer comprising

a matrix formed of one or more organic polymers and

and dispersed within said matrix:

(g) an aprotic organic liquid having a boiling point of 120 °C or higher wherein in said composite layer (A-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less with respect to the total weight of the composite layer (A-2),

said separator layer (B-1 ) comprising

a matrix formed of one or more organic polymers

and dispersed within said matrix

(g") an aprotic organic liquid having a boiling point of 120 °C or higher.

Article according to claim 5, wherein said article comprises a multilayer structure consisting of

(A-1 ) a first substrate, (A-2) a first composite layer which is a composite layer as defined in claim 5, arranged on a surface of said first substrate (A-1 ),

(C-1 ) a second solid substrate,

a matrix formed of one or more organic polymers

and dispersed within said matrix:

(a') nanoobjects comprising one or more electrochromic oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon, which are different from the electro- chromic oxides comprised by the nanoobjects (a) of the first composite layer (A-2)

(g') an aprotic organic liquid having a boiling point of 120 °C or higher

a matrix formed of one or more organic polymers

and dispersed within said matrix

(i,' i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g', g") wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said one of said layers (B), (C-2) exceeds the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in the first composite layer (A-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more. Article according to claim 5 or 6, wherein

said separator layer (B-1 ), (B) further comprises

Article according to claim 5 or 6, wherein

in said separator layer (B-1 ), (B), the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 20 ppm or less, preferably 4 ppm or less, most preferably 0.4 ppm or less with respect to the total weight of the separator layer (B-1 ).

Article according to any of claims 6 to 8, wherein

said electrochromic composite layer (C-2) further comprises

(i') at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g')

Article according to claim 6 or 7, wherein

in said electrochromic composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less with respect to the total weight of the second composite layer (C-2).

1 1. Article according to claim 6, wherein

in said first composite layer (A-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less with respect to the total weight of the first composite layer (A-2),

in said second composite layer (C-2) the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ is 100 ppm or less, preferably 20 ppm or less, most preferably 2 ppm or less with respect to the total weight of the second composite layer (C-2)

- and said separator layer (B) comprises

(i") at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g") wherein the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said separator layer (B) exceeds the total concentra- tion of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said first composite layer (A-2) as well as the total concentration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ in said second composite layer (C-2) by a factor of 5 or more, more preferably by a factor of 25 or more, further preferably by a factor of 50 or more and most preferably by a factor of 100 or more.

12. Article according to any of claims 6 to 1 1 , wherein said electrolyte (Γ), (i") is a lithium salt, preferably a lithium salt selected from the group consisting of consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sul- fonimide and lithium bis(fluorosulfonyl)imide. 13. Article according to any of claims 6 to 12, wherein in said second composite layer (C-2) and in said separator layer (B) the matrix is formed of the same organic polymers as the matrix in the first composite layer (A-2) and the aprotic organic liquid (g") having a boiling point of 120 °C or higher in the separator layer (B) and the aprotic organic liquid (g') having a boiling point of 120 °C or higher in the second composite layer (C-2) is the same as the aprotic organic liquid (g) in the first composite layer, and the nanoobjects (a) of the first composite layer (A-2) comprise one or more oxides of tungsten, and the nanoobjects (a') of the second composite layer (C- 2) comprise one or more oxides of nickel.

14. Article according to any of claims 6 to 13, wherein said solid substrates (A-1 , C-1 ) comprise one or more materials selected from the group consisting of glasses, metals and organic polymers, wherein at least one of said solid substrates (A-1 , C-1 ) exhibits a light transmission of 80 % or more measured according to DIN EN 410.

15. Method for preconditioning a multilayer structure for production of or use in an elec- trochromic device, said process comprising the steps of:

providing an article comprising a multilayer structure as defined in claim 6 applying an electric voltage between the first and the second composite layer to allow migration of cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ across the separator layer to the first composite layer.