Electrodes for electrochromic systems and electrochromic systems including said electrodes

Abstract

The present invention relates to an electrode for an electrochromic apparatus, particularly a counter electrode, which comprises an oxide of lithium, tungsten, and nickel, wherein the atomic ratio of nickel to tungsten is 0.9 to 1.1, the oxide crystallizes in an orthorhombic system, and the oxide of lithium, tungsten, and nickel preferably has the compositional formula Li x This corresponds to Ni2W2O9 (where x is between 0 and 2, including both ends).

Description

[Technical Field]

[0001] This invention relates to the field of electrochemical devices having controllable optical and / or energy properties, commonly known as “electrochromic devices.” More particularly, this invention relates to optical systems incorporating such electrochromic devices, and related manufacturing methods. [Background technology]

[0002] Electrochromic devices, under the influence of a suitable power supply, possess certain characteristics that can be altered between a colorless state and a colored state, particularly transmission, absorption, reflection, or even light scattering at specific wavelengths of electromagnetic radiation, especially in the visible and / or infrared regions. Changes in transmittance generally occur within the optical domain (infrared, visible, ultraviolet) and / or other electromagnetic radiation domains, and therefore, they are called devices with variable optical and / or energy properties, because the optical domain is not necessarily the only relevant domain.

[0003] From a thermal standpoint, glazing that can alter the absorptivity in at least a portion of the solar spectrum, when installed as exterior glazing inside buildings or as windows in means of transport such as automobiles, trains, or aircraft, allows for control of solar heat acquisition within rooms or passenger / enclosed spaces, and prevents excessive heating during strong sunlight.

[0004] Optically, they control the degree of visibility and, when installed within an external glazing, prevent glare in bright sunlight. Furthermore, they can exhibit a particularly interesting light-blocking effect when used both as external glazing and as internal glass, for example, to provide internal partitions between rooms (offices within a building) or to isolate compartments within trains or aircraft.

[0005] Structurally, the electrochromic laminate has two electrodes sandwiched between two transparent electrically conductive layers. At least one of these electrodes has an electrochromic material adapted, by definition, to reversibly and simultaneously insert ions and electrons, and the oxidation states corresponding to the insertion and deinsertion states exhibit different colors, with one state exhibiting relatively higher light transmittance than the other. This insertion or deinsertion reaction is controlled by the two transparent conductive layers, which are powered by a current generator or a voltage generator.

[0006] The first electrode, called the working electrode, is made of a cathode electrochromic material, which is adapted to capture ions when a voltage is applied across the terminals of the electrochromic system. The coloration of the working electrode corresponds to its most reduced state.

[0007] This working electrode is related to a second electrode, called the anode counter electrode, which has the ability to reversibly insert cations and is symmetrical with respect to the working electrode. In other words, this counter electrode is adapted to release ions when a voltage is applied across the electrochromic system. This counter electrode consists of a layer that is preferably achromatic, or at least slightly colored, when the working electrode is in a colorless state, and preferably has color in the oxidized state, thereby enhancing the overall contrast between the colored state and the colorless state of the electrochromic laminate.

[0008] The working electrode and the counter electrode are separated by an interfacial region generally called the "electrolyte" (ion conduction layer (IC)), which has a dual function as both an ion conductor and an electrical insulator, although this can be optional. Thus, the ion conduction layer prevents any short circuits between the working electrode and the counter electrode. It also allows both electrodes to retain charge, thus maintaining their colorless and colored states.

[0009] According to a particular embodiment, such an electrolyte is formed by depositing different intermediate layers between a working electrode and a counter electrode. The boundaries between these three layers are defined by abrupt changes in composition and / or microstructure. Thus, such an electrochromic laminate has at least three distinct layers separated by two distinct abrupt interfaces.

[0010] Alternatively, the working electrode and the counter electrode are stacked and generally in contact with each other during deposition, and only after this process, a transition region that functions as an electrolyte is formed by the movement of components within the electrodes during the manufacturing process, particularly during the laminate heating stage.

[0011] The two conductive layers mentioned above are positioned on both sides of the electrode, as shown in the attached Figure 1.

[0012] Therefore, this electrochromic device has two different subassemblies: a cathode subassembly having a working electrode, and an anode subassembly having a counter electrode. [Overview of the project] [Problems that the invention aims to solve]

[0013] The material selection for the counter electrode is particularly important in electrochromic applications. Naturally, it must be stable against repeated charge-discharge cycles. Furthermore, the material must have the highest possible Li+ / Li potential. This high potential ensures system efficiency. In particular, a high potential allows the entire electrochromic device to operate at relatively high potentials, thereby significantly reducing the time required for device changeover.

[0014] Patent Publication No. 2014 / 143410 describes an anode layer material comprising lithium, nickel, and elements selected from tungsten (W) and molybdenum (Mo), where the atomic ratio of (Mo+W) / (Mo+W+Ni) is 0.025 to 1. Examples herein describe compounds in which the Ni / W atomic ratio is significantly greater than 1. As reported in Table 3 herein, electrodes obtained with such compounds are Li + It has a potential of 2.88V to 3.56V relative to Li.

[0015] In particular, in large electrochromic devices, that is, in devices where the electrochromic system is incorporated on a large support (glazing), the switching speed is limited by the voltage drop along the surface of the device. This voltage drop is due to the limited conductivity of the materials constituting the electrochromic system. When such an electrochromic device is operated at a relatively high voltage, the effect of this voltage drop on the voltage distribution across the entire surface of the device is reduced because the relatively high voltage reduces the relative voltage drop at the center of the device. As a result, the device switches relatively uniformly, and the final state is reached relatively quickly. [Means for solving the problem]

[0016] More particularly, in order to solve the aforementioned objectives and problems, the present invention relates to an electrode, especially a counter electrode, for an electrochromic apparatus, comprising, preferably comprising, an oxide of tungsten, nickel, and optionally lithium, wherein the atomic ratio of nickel to tungsten is 0.9 to 1.1, and the oxide crystallizes in an orthorhombic system.

[0017] Preferably, the electrode does not contain elements other than Li, Ni, W, and O, except for those that are present as unavoidable impurities.

[0018] According to preferred but not limited embodiments of the present invention, these are as follows, and these can obviously be combined with each other as needed:

[0019] - The atomic ratio of oxygen to nickel (O / Ni) in the above oxide is 4.0 to 5.0, particularly 4.2 to 4.8.

[0020] - The atomic ratio of oxygen to tungsten (O / W) in the above oxide is 4.0 to 5.0, particularly 4.2 to 4.8.

[0021] - The oxides of lithium, tungsten, and nickel correspond to the composition formula LixNi2W2O9, where x is from 0 to 2, including both ends, preferably from 0 to 2, not including 0, and including 2.

[0022] - x is from 0.1 to 2, including both ends, preferably from 1 to 2, including both ends.

[0023] - The above oxide crystallizes in the Pbcn space group.

[0024] - The above oxide has the following lattice constants: - a = 8.69 Å ± 0.10 Å (0.869 nm ± 0.010 nm), - b = 5.06 Å ± 0.10 Å (0.506 nm ± 0.010 nm), and - c = 14.34 Å ± 0.10 Å (1.434 nm ± 0.010 nm).

[0025] - The above oxide has a layered structure composed of a continuum of NiO6 and WO^6 octahedral sheets, spaced by a plane into which lithium atoms are inserted, and the distance between the two closest tungsten atoms belonging to two consecutive octahedral sheets is preferably greater than 3 Å (0.3 nm), or even greater than 4 Å (0.4 nm).

[0026] The present invention also relates to an anode sub - assembly for an electrochromic system, the anode sub - assembly being adapted to be deposited on top of a glass functional substrate and having an electrode, particularly a counter - electrode, as described above.

[0027] - The above anode subassembly may have, in particular, the following: - Transparent conductive layer (2B), - A counter electrode (5) comprising the aforementioned electrodes and positioned above the first transparent conductive layer (2B).

[0028] -In the anode subassembly described above, according to the first embodiment, the counter electrode is in the form of a layer in contact with the transparent conductive layer.

[0029] - According to another embodiment, the counter electrode is in the form of a layer in contact with the transparent conductive layer, the layer consisting of crystalline particles of nickel tungsten oxide dispersed in an organic or inorganic matrix.

[0030] The present invention further relates to an electrochromic system incorporating a glass functional substrate and having the aforementioned electrodes, particularly the aforementioned anode subassembly.

[0031] The electrochromic system advantageously incorporates the following from the surface of the above-mentioned substrate: - A cathode subassembly having a first transparent conductive layer and a working electrode; - The aforementioned anode subassembly, in particular, comprising a counter electrode containing the above-mentioned lithium, tungsten, and nickel oxides, and a second transparent electrical conductive layer disposed below the counter electrode, in a continuous manner. - Lithium (Li) ions introduced into the electrochromic system described above.

[0032] Preferably, the electrochromic system further comprises different layers of ion conductors interposed between the electrode and the counter electrode.

[0033] In such an electrochromic system, the working electrode is advantageously tungsten oxide, particularly WO3, and optionally tungsten oxide doped with an element selected from nickel, niobium, molybdenum, tantalum, titanium, vanadium, zinc, and zirconium, or alternatively vanadium oxide, particularly V2O5.

[0034] The thickness of the working electrode is typically 100–1500 nm.

[0035] The thickness of the counter electrode is generally 100 to 1500 nm.

[0036] Finally, the present invention relates to glazing incorporating the aforementioned electrochromic system, which is suitable for use as building glazing, particularly as exterior glazing for interior partitions or glass doors, or as glazing for interior partitions or windows of means of transport, such as trains, aircraft, cars, or ships.

[0037] Such glazing may have at least two glass substrates and incorporate the aforementioned electrochemical system.

[0038] It should be noted that, in this specification, the deposition of one layer above or below another does not necessarily mean that the two layers are in direct contact with each other. Here, the terms “above” and “below” refer to the order in which these various elements are arbitrarily selected and arranged on the surface of the glass functional substrate. Alternatively, such arrangement order can be reversed for this same substrate. Furthermore, two layers deposited in overlapping positions may be physically separated, for example, by one or more intermediate layers. Similarly, the term “between” does not necessarily mean that the three specified elements are in direct contact with each other.

[0039] The glass functional substrate is, of course, a glass substrate, but alternatively, any rigid plastic material, such as PMMA or polycarbonate, can support the electrochromic system within the glazing. However, preferably, the substrate is made of glass.

[0040] According to a preferred embodiment, the working electrode is deposited by magnetron sputtering. Alternatively, the deposition is carried out using a liquid process.

[0041] According to a particular embodiment, the working electrode is composed of at least tungsten oxide (WOx) doped with at least one transition metal element Y selected from the group including niobium (Nb), molybdenum (Mo), vanadium (Va), tantalum (Ta), titanium (Ti), nickel (Ni), zinc (Zn), and zirconium (Zr), as described in International Application No. 2021 / 123267.

[0042] The present invention also relates to an electrochromic system adapted to be deposited on top of a glass functional substrate, which has the following features: - The aforementioned cathode subassembly, - Counter electrode located above the cathode subassembly mentioned above, - A second transparent conductive layer above the counter electrode, - Lithium (Li) ions introduced into the above electrochromic system, and - Preferably, different layers of ion conductors interposed between the electrode and the counter electrode.

[0043] The present invention also relates to an electrochromic system adapted to be deposited on top of a glass functional substrate, which has the following features: - A second transparent conductive layer positioned above the above substrate, - Counter electrode located above the second transparent conductive layer, - The aforementioned cathode subassembly, located above the counter electrode, - Lithium (Li) ions introduced into the above electrochromic system, and - Preferably, different layers of ion conductors interposed between the electrode and the counter electrode.

[0044] Thus, during the manufacturing of electrochromic systems, the order in which the laminates are deposited on the substrate may be reversed, and therefore, the order in which the counter electrode is deposited above the working electrode, or the order in which the working electrode is deposited above the counter electrode, may be alternating.

[0045] In this specification, the process of introducing lithium (Li) ions into the electrochromic system can be carried out in various ways. Preferably, one or more different lithium layers are interposed within the electrochromic system, and the lithium ions diffuse into the electrochromic layer spontaneously and / or as a result of rising temperature.

[0046] According to a particular embodiment, the counter electrode is tungsten-nickel oxide (NiW x O z It consists of at least ) which is preferably doped with at least one transition metal element.

[0047] According to one embodiment, - The thickness of the working electrode (3) is 100 to 1500 nm, preferably 150 to 1000 nm, more preferably 200 to 700 nm, even more preferably 300 to 500 nm, most preferably 350 to 450 nm, and / or - The thickness of the counter electrode (5) is 100 to 1500 nm, preferably 150 to 500 nm, more preferably 200 to 350 nm, even more preferably 225 to 300 nm, and most preferably 260 to 280 nm.

[0048] The present invention also includes obtaining an electrochromic device by assembling a reinforced cathode subassembly on one side and an anode subassembly on the other. Such an anode subassembly has at least one opposing substrate on which a second transparent conductive layer and an opposing electrode are deposited. Preferably, the anode subassembly is thermally reinforced.

[0049] The present invention also relates to glazing incorporating such reinforced electrochromic systems, which is suitable for use as building glazing, particularly as exterior glazing for interior partitions or glass doors, or as glazing for interior partitions or windows of means of transport, such as trains, aircraft, cars, or ships.

[0050] Further features and advantages of the present invention will become apparent from the following description of specific embodiments, which are presented as illustrative and non-limiting examples, and from the accompanying drawings, with respect to these: [Brief explanation of the drawing]

[0051] [Figure 1] Figure 1 is a schematic diagram of an electrochromic system according to a specific embodiment of the present invention.

[0052] [Figure 2] Figure 2 is a graph showing the potential of the electrode according to the present invention, which contains the crystalline compound LixNi2W2O9, compared to the potential of the electrode containing the material LixNiyWOz (y>2), as described in Prior Art International Publication No. 2014 / 143410.

[0053] [Figure 3]Figure 3 is a graph showing the potential difference between the counter electrode and the working electrode in the electrochromic apparatus according to the present invention shown in Figure 1, where the transparent conductive layer is made of ITO, the working electrode is made of WO3, and the solid electrolyte layer is made of LiSiOx. The counter electrode according to the present invention contains the crystalline compound LixNi2W2O9, while the prior art contains the material LixNiyWOz (y>2).

[0054] [Figure 4] Figure 4 shows the discharge capacity of the electrochemical system when performing a continuous charge-discharge cycle of the electrode according to the present invention.

[0055] [Figure 5] Figure 5 shows the structure of the LixNi2W2O9 electrode material according to the present invention, obtained by Rietveld analysis. [Modes for carrying out the invention]

[0056] Unless otherwise specified, reference numbers used in Figure 1 and reported herein refer to similar or identical elements.

[0057] The various elements illustrated in the diagrams are not necessarily shown to actual size, and the focus is on illustrating the general operation of the present invention.

[0058] Some specific embodiments of the present invention are shown below. It should be understood that the present invention is not limited in any way by these specific embodiments, and other embodiments are entirely possible.

[0059] According to a particular embodiment, as shown in Figure 1, the present invention relates to an electrochromic system (8) deposited on a glass functional substrate (1), which, in the order of deposition, comprises: a first transparent conductive layer (2A), preferably made of indium tin oxide (ITO); a working electrode (3) made of tungsten oxide (WOx), which may be doped with an element selected from Ni, Nb, Mo, Ta, Ti, V, Zn, and Zr; and an electrolyte (4), for example, lithium silicon oxide (LiSiO). x An electrolyte (4), a counter electrode (5), comprising or derived from ) and having the general formula Li x A counter electrode (5) comprising or derived from lithium nickel tungsten oxide according to the present invention, Ni2W2O9 (0≦x≦2), and a second transparent conductive layer (2B) of indium tin oxide (ITO).

[0060] At this stage, lithium (Li) ions have already been introduced into the electrochromic system by the deposition of two different lithium layers: the first between the working electrode and the electrolyte, and the second between the counter electrode and the second transparent conductive layer. It should be noted that after each deposition, a heating process is performed to induce the diffusion of lithium ions into the electrochromic stack.

[0061] In a preferred embodiment, at least a portion, preferably all, of the layers forming the electrochromic laminate are deposited by magnetron sputtering. In another embodiment, at least a portion of these layers are deposited using an alternative method, such as liquid-phase deposition.

[0062] During operation, the anode material of the electrode according to the present invention (preferably Li x(Ni2W2O9) has the ability to electrochemically exchange lithium. Following this lithium exchange, the oxidation state of the material changes. In the reduced state (i.e., containing the maximum amount of Li within the crystal lattice, for example x = 2), the light absorption rate of the material is minimized. In the oxidized state (i.e., containing the minimum amount of Li within the crystal lattice, for example 1 ≦ x < 2), the light absorbance of the material in the visible light region is maximized. And it is referred to as anodic coloring. This color change is due to the change in the oxidation state of nickel atoms: Ni 2+ / Ni 3+ and may be caused by Ni 3+ species absorb more visible light than Ni 2+ species.

[0063] According to another embodiment not shown, the deposition order of the electrochromic laminate on the substrate may be reversed, whereby it has the following deposition order: a first transparent conductive layer (2A) made of indium tin oxide (ITO), a counter electrode (5) made of lithium nickel tungstate according to the present invention, an electrolyte (4) which contains or consists of, for example, lithium silicon oxide, for example LiSiO x , an electrolyte (4), a working electrode (3) made of tungsten oxide (WOx) optionally doped, and a second transparent conductive layer (2B) made of indium tin oxide (ITO). And the working electrode is deposited above the counter electrode.

[0064] According to these two alternative embodiments, the first transparent conductive layer and the working electrode form a cathode subassembly (6), while the counter electrode and the second transparent conductive layer form an anode subassembly (7).

[0065] Therefore, a preferred electrochromic device according to the present invention is completely solid and consists of a laminate of thin film layers on a transparent substrate (glass or plastic). At least five layers make up the laminate: - A first transparent conductive layer (ITO, SnO2:F, etc.), - A working electrode layer (WO3, TiO2, V2O5, etc.), - Ion-conducting layer (LiSiOx, etc.) - Counter electrode layer according to the present invention, - A second transparent conductive layer (ITO, SnO2:F, etc.).

[0066] Further layers may be used: - Multiple layers of various compositions within the working electrode layer and the counter electrode layer, - A layer that improves optical properties (such as anti-reflective properties) between the substrate and other layers, or at the air interface. - Sealing layer at the air interface, - A buffer layer between the electrode and the transparent conductive layer.

[0067] According to one possible alternative to the present invention, the electrochromic apparatus may consist of two transparent substrates (glass or plastic) on which at least two layers are deposited, and these constitute the components of the apparatus.

[0068] The two aforementioned components are joined together by an organic intermediate layer (polymer gel) that functions as an ion conductor, so that the electrode material and the counter electrode material face each other.

[0069] At least the following layers are deposited on the first substrate: - First transparent conductive layer (ITO, SnO2:F, etc.) - Working electrode layer (e.g., WO3, optionally doped, TiO2, V2O5, etc.).

[0070] At least the following two layers are deposited on the second substrate: - Second transparent conductive layer (ITO, SnO2:F, etc.) - The counter electrode layer according to the present invention.

[0071] The intermediate gel may comprise at least one polymer, a lithium salt, a solvent for dissolving the salt, and a plasticizer for the polymer. [Examples]

[0072] The illustrative examples described below highlight some of the technical advantages of the electrodes according to the present invention, but do not limit the scope of the claims.

[0073] The material according to the present invention is synthesized as follows: Li2Ni2W2O9 powder is synthesized by ceramic synthesis from nickel oxide powder (NiO, Sigma-Aldrich, 99%), tungsten oxide (WO3, Alfa Aesar, 99.8%), and lithium carbonate (Li2CO3, Sigma-Aldrich, ≥99.0%). The powders are mixed in an agate mortar and then transferred to a steel jar containing two steel balls. The entire batch is placed in a mechanical mill (SPEX SamplePrep 8000M Mixer / Mill) and subjected to high-energy mechanical grinding for 30 minutes.

[0074] The obtained powder is deposited in an alumina crucible and placed in a Carbolite CWF 1200 muffle furnace. The powder is heated in air at a rate of 5°C / min to 650°C, and then held in the furnace at this temperature for 12 hours to ensure decarburization of lithium carbonate. The powder is then annealed at 700°C for 24 hours. The resulting powder is mechanically ground again for 30 minutes and held at 700°C for 24 hours to ensure a complete reaction.

[0075] First, a constant current charge-discharge test was performed using a button cell obtained from synthetic powder in a two-electrode configuration. For measuring the potential of the electrode containing Li2Ni2W2O9 according to the present invention, it was mixed with Super P carbon black (20% by weight), and the other electrode was made of lithium metal. Aluminum foil and stainless steel plate were used as current collectors for the positive and negative electrodes, respectively. Two layers of Whatman GF / D glass fiber filter were used as a separator between the two electrodes. The electrolyte was a 1M solution of lithium hexafluorophosphate (LiPF6) in a mixture of ethylene carbonate (EC), propylene carbonate (PC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:4.

[0076] Measurements were performed using a BioLogic BCS-805 battery cycler, and data was acquired using EC-Lab. The cell was measured at room temperature and atmospheric pressure with a current density of 10 mA·g. -1 So, Li + The Li battery is cycled at 2.5-5.0V. Three button batteries are cycled under the same conditions to confirm the reproducibility of their electrochemical behavior and to obtain a certain statistical variance in these measurements.

[0077] For comparison, the same constant current charge-discharge experiment will be performed with the same two-electrode configuration, but this time with Li > 2. x Ni y WO z The potential of the electrode made of is measured in accordance with the International Publication No. 2014 / 143410 of the prior art.

[0078] Figure 2 shows the potential (V vs. Li+ / Li) of the electrode containing the Li2Ni2W2O9 material according to the present invention (dotted curve) and the aforementioned reference electrode, from a colorless state, i.e., a state in which the material absorbs little to no visible light (Li2Ni2W2O9), to a dark state, i.e., a state in which it absorbs a relatively large amount of visible light, due to lithium ion desorption, and consequently Li<2 2-x This is shown based on the charges exchanged when the state changes to one corresponding to the Ni2W2O9 empirical formula.

[0079] The results shown in Figure 2 demonstrate the essential advantages of the present invention: electrodes containing the Li2Ni2W2O9 material according to the present invention react at a much higher potential than Li / Li+, in the range of 4.5V to 5.0V.

[0080] Due to this characteristic, the electrochromic system according to the present invention can be expected to be relatively efficient. In particular, this potential increase ultimately allows the entire electrochromic device to operate at a relatively high potential, thereby significantly reducing the time required for switching.

[0081] An electrochromic apparatus using the counter electrode according to the present invention is constructed based on the model described above in relation to Figure 1, and a similar apparatus is constructed using the conventional electrochromic apparatus using the counter electrode described above.

[0082] Figure 3 shows the potential difference between the counter electrode and the working electrode for an electrochromic system using one of two counter electrodes. It can be seen that the potential difference is remarkably high in the device according to the present invention, which significantly reduces the time required to switch between systems according to the present invention.

[0083] Figure 4 shows the discharge capacity of the electrode according to the present invention during a continuous charge-discharge cycle. It can be seen that this capacity does not change during the continuous cycle, thereby guaranteeing the durability of the electrode in electrochromic applications.

[0084] X-ray diffraction and neutron diffraction analysis were performed on Li x The procedure is performed on Ni2W2O9 oxide material. Its structure is determined from the diffraction pattern obtained using the Rietold method. The material crystallizes in an orthorhombic lattice in the Pbcn space group, and its lattice constants after purification are a=8.69 Å (0.869 nm), b=5.06 Å (0.506 nm), and c=14.34 Å (1.434 nm).

[0085] The obtained oxide structure is shown in Figure 5. A layered structure can be observed, containing a continuum of NiO6 and WO6 octahedral sheets along the c-axis, which are spaced by planes into which lithium atoms are inserted. According to the present invention, the distance between the two nearest tungsten atoms belonging to two consecutive octahedral sheets is approximately 4.13 Å (see attached Figure 5).

[0086] Furthermore, X-ray diffraction demonstrates that oxide materials do not undergo structural changes under continuous charge-discharge cycles.

[0087] While specific embodiments of the present invention have been illustrated and described, it is clear that various other changes and modifications can be made within the spirit and scope of the invention. Therefore, this specification is intended to encompass all modifications within the scope of the invention in the appended claims.

Claims

1. An electrode for an electrochromic apparatus, particularly a counter electrode, comprising an oxide of tungsten, nickel, and optionally lithium, wherein the atomic ratio of nickel to tungsten (Ni / W) is 0.9 to 1.1, and the oxide belongs to the orthorhombic crystal system.

2. The electrode according to claim 1, wherein the atomic ratio of oxygen to nickel in the oxide (O / Ni) is 4.0 to 5.0, particularly 4.2 to 4.

8.

3. The electrode according to claim 1 or 2, wherein the atomic ratio (O / W) of oxygen in the oxide to tungsten is 4.0 to 5.0, particularly 4.2 to 4.

8.

4. The aforementioned lithium, tungsten, and nickel oxides have the composition formula Li ｘ Ni ２ W ２ O ９ The electrode according to any one of claims 1 to 3, wherein x is between 0 and 2 and includes both ends.

5. The electrode according to any one of claims 1 to 4, wherein x is 1 to 2 and includes both ends.

6. The electrode according to any one of claims 1 to 5, wherein the oxide crystallizes in the Pbcn space group.

7. The oxide has the following lattice constants: - a = 8.69 Å ± 0.10 Å, - b = 5.06 Å ± 0.10 Å, and, - c = 14.34 Å ± 0.10 Å, An electrode according to any one of claims 1 to 6, having the following characteristics.

8. The aforementioned oxide is NiO ６ and WO ６ The electrode according to any one of claims 1 to 7, having a layered structure consisting of a continuum of octahedral sheets, spaced apart by planes in which lithium atoms are inserted, and the distance between the two closest tungsten atoms belonging to two consecutive octahedral sheets is preferably greater than 3 Å, or even greater than 4 Å.

9. an anode subassembly (7) for an electrochromic system (8), wherein the anode subassembly (7) is adapted to be deposited on top of a glass functional substrate (1), and has an electrode, particularly a counter electrode, according to any one of claims 1 to 8.

10. The following: - Transparent conductive layer (2B), - Counter electrode (5), which is made of an electrode according to any one of claims 1 to 7 and is positioned above the first transparent conductive layer (2B), The anode subassembly according to claim 9, having the following features.

11. The anode subassembly (7) according to claim 10, wherein the counter electrode is in the form of a layer in contact with the transparent conductive layer.

12. The anode subassembly (7) according to claim 10, wherein the counter electrode is in the form of a layer in contact with the transparent conductive layer, and the layer consists of crystalline particles of nickel tungsten oxide dispersed in an organic or inorganic matrix.

13. Electrochromic system (8), comprising a glass functional substrate (1), and having an electrode according to any one of claims 1 to 8, particularly an anode subassembly according to any one of claims 9 to 12.

14. From the surface of the aforementioned substrate, the following: - A cathode subassembly having a first transparent conductive layer (2A) and a working electrode (3); - An anode subassembly (7) according to any one of claims 9 to 12, more particularly an anode subassembly (7) comprising, in a continuous manner, a counter electrode (5) comprising the lithium, tungsten, and nickel oxides according to any one of claims 1 to 8, and a second transparent electrical conductive layer (2B) disposed below the counter electrode (5), - Lithium (Li) ions introduced into the electrochromic system (8), The electrochromic system (8) according to claim 13, which incorporates the following.

15. The electrochromic system (8) according to claim 13 or 14, further comprising a different layer (4) of an ion conductor interposed between the electrode and the counter electrode.

16. The working electrode contains tungsten oxide, particularly WO ３ and optionally contains tungsten oxide doped with an element selected from nickel, niobium, molybdenum, tantalum, titanium, vanadium, zinc, zirconium, or contains vanadium oxide, particularly V ２ O ５ The electrochromic system (8) according to any one of claims 13 to 15, containing

17. The electrochromic system (8) according to any one of claims 13 to 16, wherein the thickness of the working electrode (3) is 100 to 1500 nm.

18. The electrochromic system (8) according to any one of claims 13 to 17, wherein the thickness of the counter electrode (5) is 100 to 1500 nm.

19. A glazing incorporating the electrochromic system described in any one of claims 13 to 18, wherein the glazing is suitable for use as building glazing, particularly as exterior glazing for interior partitions or glass doors, or as glazing for interior partitions or windows of means of transport, such as trains, aircraft, cars, or ships.

20. The glazing according to claim 19, comprising at least two glass substrates and incorporating the electrochemical system according to any one of claims 13 to 18.

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