Electrochromic devices

Electrochromic devices incorporate reversible oxidizers to improve device kinetics, incorporate counterelectrodes composed of an alkali metal oxide and vanadium oxide to improve stability, and doped tungsten or molybdenum oxide in the electrochromic layer to improve UV durability.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to electrochromic devices that have improved
 kinetics, improved counterelectrodes, and improved resistance to
 degradation from ultraviolet (UV) radiation. In particular, the present
 invention relates to electrochromic devices that incorporate i) reversible
 oxidizers to improve device kinetics, ii) counterelectrodes composed of an
 alkali metal oxide and vanadium oxide to improve stability, and iii) an
 electrochromic layer formed from doped tungsten or molybdenum oxide to
 improve UV durability.
 2. Related Background
 Electrochromic (EC) devices are used to make variable transmission and
 reflection glazing and mirrors that may be used for example in automotive
 and architectural applications. These EC devices can also be fabricated as
 light filters and displays for a variety of uses. Such devices can be used
 for energy efficient windows (architectural and transportation),
 skylights, automotive mirrors, displays, lighting control filters, etc. EC
 devices color and/or darken in response to an electric voltage. There are
 several types of electrochromic devices used to modulate light in a
 variety of applications. Most electrochromic devices have at least one
 electrochromic electrode which typically reversibly changes color upon ion
 insertion (reduction). For example, electrochromic devices may include i)
 an electrochromic layer (electrode) and ii) a redox material incorporated
 in an electrolyte layer. Many EC devices have another type of construction
 in which a liquid electrolyte or a polymeric solid electrolyte separate
 two electrodes, where at least one is electrochromic and where the other
 is a counter electrode (which could also be electrochromic) for ion
 insertion (see e.g., FIG. 1). The electrolyte may further include an
 anodic or cathodic dye. Many EC devices may also incorporate multiple thin
 coatings on one substrate.
 Various examples of EC devices are found, for example, in U.S. Pat. No.
 5,239,405 which describes electrochemichromic solutions, U.S. Pat. No.
 4,902,108 which describes a single-compartment, self-erasing, solution-
 phase EC device, U.S. Pat. No. 5,729,379 which describes electrochemically
 active polymers, U.S. Pat. No. 5,780,160 which describes EC devices
 employing an electrochromically-inert reducing or oxidizing additive, U.S.
 Pat. No. 5,724,187 which describes EC devices containing redox reaction
 promoters, U.S. Pat. No. 4,671,619 which describes electrolytic solutions
 containing an iodide source material as a redox reaction promoter, and
 U.S. Pat. No. 5,725,809 which describes EC windows containing an
 ultraviolet stabilizer. Other examples are found in International Patent
 Publication WO 98/42796 which describes electrochromic polymeric solid
 films, International Patent Publication WO 97/38350 which describes an EC
 device containing a selective ion transport layer, and International
 Patent Publication WO 98/44384 which describes an EC device containing
 electroactive materials having a preselected perceived color. The
 disclosures of the above patents and publications are incorporated by
 reference herein.
 The kinetics in EC devices, such as their bleaching and/or their coloration
 rates, disadvantageously decrease when the electrolyte thickness is
 increased because the electron carrier ions must travel longer distances.
 Therefore, it would be desirable to develop additives that, when added to
 the electrolyte, improve the coloration kinetics.
 Further, it would be desirable to develop devices in which the coloration
 kinetics are insensitive to the gap (electrolyte thickness) between the
 electrodes. For example, in applications where curved glass is used over
 large areas (such as in automotive glass windows), large gaps of about 0.5
 to 3 mm might be preferred between the glass plates. However, the glass
 bending tolerances can cause the interglass gap to vary from 10 to 50%.
 Such variations in the interpane gap distance can disadvantageously lead
 to non-uniform color due to the different coloration/bleaching rates for
 each gap distance. Devices having coloration kinetics that are insensitive
 to the gap would not exhibit such color variations.
 A typical chromogenic layer utilized in EC devices such as a window is
 composed of, for example, tungsten oxide deposited on a transparent
 conductive substrate. A typical redox material used in the electrolyte is,
 for example, ferrocene. This electrolyte is sandwiched between the
 tungsten oxide layer described above and another transparent conductive
 substrate. When the EC cell is colored by applying an appropriate coloring
 potential, the tungsten oxide is reversibly reduced to a colored compound,
 tungsten bronze, while the ferrocene is reversibly oxidized to ferrocenium
 at the counterelectrode. When the bleaching potential is applied, (or
 under bleaching conditions) the ferrocenium oxidizes the tungsten bronze
 back to tungsten oxide, while the ferrocenium is itself reduced to
 ferrocene. The rate of such oxidation (or the bleaching rate) will depend
 in large part on the concentration of the ferrocenium near the bronze
 layer, the rate of transportation of ferrocenium through the electrolyte
 layer and the strength of ferrocenium as an oxidizer. Accordingly, it
 would be desirable to enhance the bleaching rate of EC devices in order to
 enhance their kinetics.
 As described above, electrochromic devices can reversibly change light
 transmission or coloration when an electrical stimulus is applied. In many
 applications, electrochromic devices are subjected to not only visible and
 IR radiation but also UV radiation. Continued exposure to UV radiation can
 disadvantageously cause deterioration of materials and components, thereby
 leading to deterioration of the properties of the EC device. Thus, it
 would be desirable to minimize the change and/or degradation of these
 devices when subjected to UV radiation.
 Many of the semiconductor materials utilized in EC devices can interact
 with other layers of the EC devices. For example, the semiconductor
 materials can undesirably interact with the electrolyte and transparent
 conductor layers when exposed to UV to shorten the EC devices' useful
 lifetimes. One of the effects from exposure to UV is the reduction in the
 transmission/reflection of the EC devices. This effect may be called
 "photochromism". Even more undesirably, the photochromism effect can be
 irreversible, i.e., cannot be reversed by applying a bleaching potential
 to the EC devices.
 As described above, most electrochromic devices have at least one
 electrochromic electrode (an electrochromic or EC layer) that typically
 changes color reversibly upon ion insertion (reduction). Many EC devices
 use oxides of tungsten, molybdenum, or niobium as such electrochromic
 electrodes. The tungsten, molybdenum, or niobium oxides are often mixed
 with other oxides to change their color in at least one of colored and
 bleached states, spectral characteristics, ion-insertion/extraction
 properties, color/bleach rates, reversibility, durability, etc. It would
 be particularly desirable to eliminate photochromism in such EC devices
 which use at least one layer having a composition that includes tungsten
 oxide and/or molybdenum oxide and/or niobium oxide.
 A typical prior art electrochromic device 17 is shown schematically in FIG.
 1. EC device 17 can be used, for example, as a window. EC device 17 is in
 the form of a sequence of layers. A substrate 16 is adjacent to a
 transparent conductor layer 12' which abuts a counterelectrode (CE) 15. An
 electrolyte layer 14 is disposed between the counterelectrode and an
 electrochromic layer 13, which abuts a transparent conductor 12, which is
 adjacent to a substrate 11.
 In a typical EC device, substrates 11 and 16 are often glass or a polymeric
 material, transparent conductor layers 12 and 12' are often formed from
 coatings of indium tin oxide or doped tin oxide, and electrochromic (EC)
 layer 13 is often an oxide (e.g., tungsten oxide, molybdenum oxide, etc.).
 EC device 17 is typically constructed by taking two substrates 11 and 16
 that are each already coated respectively with transparent conductors 12
 and 12'. On the 11/12 coated substrate, EC coating 13 is deposited over
 the conductor coating. On the other coated substrate 16/12', CE coating 15
 is deposited over the conductor coating. One of the coated substrates may
 be pre-reduced by ion-insertion. The two doubly coated substrates are then
 assembled together by, for example, lamination with an electrolyte or an
 ion-conductive layer therebetween. Examples of such devices are found in
 International Patent Publication WO 95/31746 which describes an
 electrochromic pane arrangement, International Patent Publication WO
 97/22906 which describes an electrochromic element, and in U.S. Pat. No.
 5,793,518 which describes an electrochromic system, the disclosures of
 each of which are incorporated by reference herein.
 Another way in which EC devices with counterelectrodes are fabricated is by
 sequential deposition of thin films on one substrate. Schematically such
 devices resemble FIG. 1, but without second substrate 16. Examples of such
 devices are described in International Patent Publication WO 94/15247
 which describes EC devices utilizing optical tuning layers, U.S. Pat. No.
 4,712,879 which describes an EC mirror, S. P. Sapers, et al., "Monolithic
 Solid State Electrochromic Coatings for Window Applications", Proc. of the
 Soc. of Vacuum Coaters Conference, 1996, and U.S. Pat. No. 5,721,633 which
 describes a wholly solid type EC device, the disclosures of each of which
 are incorporated by reference herein. It would be desirable to produce
 novel coatings which can be used as improved counterelectrodes in EC
 devices employing at least one of tungsten, molybdenum oxide and niobium
 oxide, as EC coatings. Particularly, it would be desirable to produce
 novel counterelectrodes, for EC devices, with improved stability in the
 range of environments to which such devices are exposed. Some of these
 counterelectrodes reversibly change their color when they are reduced or
 oxidized in the devices.
 The structure of the above described EC device is similar to a typical
 secondary (rechargeable) battery. In the above described devices, the EC
 layer is intercalated (charged or reduced) in the colored state of the
 device. That is, electrons are inserted into the EC layer from the
 counterelectrode in the coloration process or state. In the bleached
 state, the ions and the concomitant electrons are extracted from the EC
 layer and inserted into the counterelectrode. This process is again
 reversed for coloration.
 Following the above analogy to secondary batteries, a counterelectrode
 commonly used for secondary batteries is vanadium oxide formed by
 processing the powder at high temperature (e.g., 500.degree. C. to
 1500.degree. C.). The thus formed vanadium oxide(s) are then combined with
 other additives and binders before being applied as layered pastes onto
 metallic electrodes. Such vanadium oxide electrodes are typically opaque
 and dark in color due in part to the presence of sulfur compounds and
 carbon black powders. Although such optical properties are acceptable for
 batteries, typical EC device applications require that the electrodes
 possess optical clarity and optical uniformity--even after processing.
 Vanadium oxide (V.sub.2 O.sub.5) is used in certain EC devices as
 counterelectrodes although it is deep yellow in color. It would be
 desirable to change or vary the optical properties of such
 counterelectrodes.
 Vanadium oxide can be modified by doping with other oxides, e.g., formation
 of vanadates. Many such materials are known, as described in A. F. Wells,
 Structural Inorganic Chemistry, 5.sup.th edition, Oxford University Press,
 Oxford, United Kingdom, 1991. Nevertheless, another disadvantage to the
 existing counterelectrodes utilizing vanadium oxide is the high processing
 temperatures required. To preserve the mechanical, chemical and functional
 integrity of the conductive substrates (e.g., soda-lime glass or plastic
 coated with transparent conductive coatings) used for EC devices,
 processing temperatures lower than 500.degree. C. are desirable.
 Accordingly, it would be desirable to produce compositions and processing
 methods for counterelectrodes that are useful in EC devices--including
 counterelectrodes containing modified vanadium oxides--that utilize lower
 processing temperatures.
 A wet chemical method to add copper to tungsten oxide is described in U.S.
 Pat. No. 5,034,246. The patent describes adding a pyridine solution of
 Cu(II) acetylacetonate to a solution containing alkyl amine tungstate in
 order to produce a tungsten oxide film containing copper. The patent,
 however, does not discuss any benefits from such addition of copper. Nor
 does the patent discuss what the form of the copper was --whether the
 copper was in the final coating as an oxide or as elemental copper in a
 nano-composite.
 Further, the patent does not provide any specific disclosure of the
 conditions necessary to perform the described copper addition.
 SUMMARY OF THE INVENTION
 This invention is directed to a method to enhance the kinetics of
 electrochromic devices by adding an augmenting amount of an oxidizer or
 reducer to the electrolyte layer of the electrochromic device. This
 invention is also directed to an electrochromic device having an
 electrochromic layer and an electrolyte layer abutting the electrochromic
 layer in which the electrolyte layer contains an augmenting amount of an
 oxidizer or reducer effective to enhance the bleaching rate of the
 electrochromic layer. Most preferably, an augmenting amount of oxidizer is
 used in combination with an electrolyte layer comprising an anodic
 compound and a cathodic electrochromic layer.
 As used herein, the augmenting amount of oxidizer employed when the device
 has a cathodic electrochromic layer is an oxidizer having an oxidation
 number which is higher than the oxidation number of the redox material
 incorporated in the electrolyte layer. Coversely, the augmenting amount of
 reducer employed when the device has an anodic electrochromic layer is a
 reducer having an oxidation number which is lower than the oxidation
 number of the redox material incorporated in the electrolyte layer. T
 his invention is also directed to electrochromic devices that exhibit
 reduced photochromism by using a layer composed of tungsten oxide or
 molybdenum oxide. The tungsten or molybdenum oxide may be doped with
 oxides of at least one of lithium, sodium, or potassium.
 Yet another embodiment of this invention is directed to electrochromic
 devices that exhibit reduced photochromism by using an oxide layer
 composed of an oxide which has at least one of an element of Group 2A or
 an oxide of the 4.sup.th period in a standard periodic table of the
 elements. The Group 2A or 4th period oxide layer is situated between i) a
 transparent conductor layer and ii) an electrochromic layer such as
 tungsten oxide or molybdenum oxide layer of the electrochromic device.
 This invention is also directed to UV resistant electrochromic layers that
 may be selected from compositions described by the formulas:
EQU p(oxide of M.sub.1)+q(oxide of M.sub.2)+r(oxide of M.sub.3) (I)
EQU q(oxide of M.sub.4)+r(oxide of M.sub.3) (II)
 wherein
 M.sub.1 is at least one of lithium, sodium, or potassium; and
 M.sub.2 is at least one element of Group 2A or an element of the 4.sup.th
 period in a standard periodic table of the elements. However, the
 preferred elements are barium, vanadium, chromium, cobalt and copper.
 M.sub.3 is at least one of tungsten or molybdenum.
 M.sub.4 is at least one of barium, chromium, cobalt or copper.
 For compositions (I) and (II) the atomic ratio p/r of M.sub.1 to M.sub.3,
 is in the range of from about 0.01 to about 2; and for composition (II)
 the atomic ratio q/r of M.sub.4 to M.sub.3 is in the range of from about
 0.001 to about 0.5. PCT application WO 9908153 describes addition of
 zirconium oxide to tungsten oxide so that its color in the colored state
 (i.e., reduced state) is neutral rather than blue. Such mixtures or any
 other mixtures where additives are used to change the spectral or other
 properties of tungsten, niobium and molybdenum oxides will also benefit
 from this invention by further incorporating the inventive oxides
 described herein.
 Yet another embodiment of this invention is directed to a counterelectrode
 having a composition selected from the formulas:
EQU x(oxide of M.sub.5)+y(oxide of M.sub.6)+z(oxide of vanadium) (III)
EQU x(oxide of M.sub.5)+z(oxide of vanadium) (IV)
 wherein
 M.sub.5 is at least one of lithium, sodium, potassium, rubidium, or cesium,
 provided for composition (IV), M.sub.5 may not be sodium unless M.sub.5 is
 a mixture of oxides;
 M.sub.6 is at least one of barium, tantalum, copper, niobium, rhenium,
 titanium, cesium, cobalt, nickel, irridium or chromium;
 the atomic ratio x/z of M.sub.5 to vanadium is in the range of from about
 0.01 to about 1; and
 the atomic ratio y/z of M.sub.6 to vanadium is in the range of from about
 0.1 to about 0.8.
 Another embodiment of this invention includes a counterelectrode formed
 from a composition described by formula:
EQU y(oxide of M.sub.7)+z(oxide of vanadium) (V)
 wherein
 M.sub.7 is at least one of barium, copper or rhenium; and
 the atomic ratio y/z of M.sub.7 to vanadium is in the range of from about
 0.1 to about 0.8. Preferably the composition is formed by a liquid phase
 reaction, e.g., using sol-gel or a wet chemical deposition technique of a
 liquid precursor onto a substrate.

DETAILED DESCRIPTION OF THE INVENTION
 Referring to FIG. 7, an electrochromic device 700 includes a chromogenic
 layer 701 (for example tungsten oxide which colors upon reduction) and an
 electrolyte layer 702 incorporating a redox material (such as ferrocene).
 The redox material (in this example, metallocene, in particular ferrocene)
 includes a reducing and oxidizing form (in this example, ferrocenium is
 the oxidizing form and ferrocene is the reducing form). Typically, the
 uncolored oxide is converted to a colored bronze to produce a chromogenic
 effect. An important factor in the overall kinetics of EC devices is the
 rate that the colored bronze is oxidized back to the uncolored oxide. The
 rate of such oxidation (or the bleaching rate), among other parameters,
 will depend importantly on the concentration of ferrocenium near the
 bronze layer and the strength of ferrocenium as an oxidizer. Accordingly,
 in one aspect, this invention enhances the kinetics of EC devices by
 enhancing the bleaching rate.
 The bleaching rate is enhanced by forming electrolyte layer 702 containing
 an increased or augmented concentration of reversible oxidizer.
 To enhance the kinetics is to increase the rate at which a reaction occurs,
 as measured by a physical manifestation of the reaction. Such
 manifestations include, for example, the amount of darkening over a period
 of time (kinetics of coloring), and the amount of lightening over a period
 of time (kinetics of bleaching). Accordingly, enhancing the bleaching rate
 means achieving a measured amount of lightening over a shorter time period
 than that time period required for the same amount of lightening at the
 unenhanced bleaching rate. As an example, if it takes 180 seconds for an
 unmodified device to lighten from 25% T to 60% T at a particular bleaching
 voltage V.sub.bleaching, then the bleaching rate is enhanced if the device
 when modified achieves a change from 25% T to 60% T at V.sub.bleaching in
 a time shorter than 180 seconds.
 This invention enhances the bleaching rate by increasing or augmenting the
 reversible oxidizer (for example, ferrocenium) concentration in
 electrolyte layer 702. Thus, for a given oxidizer, its oxidation potential
 relative to the bronze and other such colored species present in the
 electrolyte is increased by conveniently adding an effective augmenting
 amount of the oxidizer ion to electrolyte layer 702, thereby enhancing the
 bleaching rate. This oxidizer is present in the EC cell in the bleached
 state. For example, ferrocenium can be conveniently added by adding its
 salt to the electrolyte. Such oxidized metallocene salts, e.g.,
 ferrocenium salts include, for example, ferrocenium hexafluoro phosphate,
 and ferrocenium tetrafluoro borate.
 In the case of other reducing agents other than ferrocene such as, for
 example, I.sup.- (iodide) or tetramethylphenylenediamine (TMPD), their
 respective oxidizing forms would be I.sub.2 (iodine) and TMPD.sup.+.
 Accordingly, this invention would add effective augmenting amounts of the
 oxidizer to the electrolyte layer, thereby enhancing the bleaching rate.
 Such species can be conveniently added to the electrolyte. Such species
 includes, for example, I.sub.2 and [TMPD.sup.+. ClO.sup.-.sub.4 ].
 The choice of such an oxidizer to be added to electrolyte layer 702,
 however, containing a reducing compound is not limited to the
 corresponding oxidizing ion or salt. Any convenient reversible oxidizer
 that will oxidize the bronze (for example, tungsten bronze) may be used.
 For ferrocene, for example, the oxidizer could be a salt of the
 ferrocenium derivative (e.g., butyl ferrocenium salt). However, the
 oxidizer can even be unrelated to ferrocene (that is, not contain iron).
 Examples of such oxidizers include tetracyanoquinodimethane (TCNQ),
 dichlorodicyanobenzoquinone (DDQ), iodine (I.sub.2), and copper.sup.(2+)
 triflate.
 In general, the augmenting amount of oxidizer, e.g., ferrocenium should be
 in a molar ratio in the range of from about 0.01 to about 0.5, preferably
 from about 0.02 to about 0.1 of the concentration of the reducing
 compound, e.g., ferrocene.
 Some of the kinetics-enhancing additives described above also promote the
 UV stability of the devices by oxidizing bronzes undesirably formed from
 the photochromic interaction of the materials in the EC device with solar
 radiation. In one embodiment of this invention, additives are utilized
 that are activated in the presence of UV (UV active oxidizers) whereby,
 when activated, the additives become oxidizers of such undesirably formed
 bronzes. Such oxidizers include, for example, 2,4,6-triphenylpyrylium
 tetrafluoro borate, [2,4,7-trinitro-9-fluoroenone] and C.sub.60
 (fullerene).
 In general, the augmenting amount of UV active oxidizer should be in the
 same range as the oxidizers described above.
 For those EC devices where the electrochromic layer colors by oxidation
 (e.g. polyaniline and its derivatives) and where the electrolyte includes
 a redox material in an oxidizing form, the bleach rate may be enhanced by
 adding a redox agent in the reducing form to enhance the bleach rate.
 Referring to FIG. 8, another EC device 800 of this invention has an
 electrolyte 802, containing at least one anodic compound, one cathodic
 compound, and an augmenting amount of oxidizer. Electrolyte 802 is
 enclosed in a gap 804 between a conductive layer 801 and conductive layer
 803.
 This invention could be used for any convenient gap distance by utilizing a
 convenient augmenting amount of oxidizer effective to cause an
 acceleration in cell kinetics. An acceleration in cell kinetics is readily
 determined by one skilled in the art by measuring and comparing the time
 durations required for bleaching from one coloration to a bleached
 coloration--with and without added oxidizer. An effective augmenting
 amount of oxidizer shortens the measured time duration. Generally,
 augmenting amounts of oxidizers in the concentration range described above
 are effective for gaps in the range of 0.05 mm to 5 mm, for which
 acceleration in cell kinetics (color and/or bleach) is expected.
 Other additives such as water, acids (e.g. phosphoric acid), dissociable
 salts (e.g., salts of lithium sodium and potassium), UV stabilizers (such
 as benzotriazole, benzophenone, salicyclates, nickel salts, benzoates,
 formamidines, oxalanilides, hindered amines and diphenylacrylate),
 thickeners (e.g.,polymers such as polymethylmethacrylate and vinylidene
 fluoride resins (e.g., various Kynar grades produced by Elf Atochem North
 America, Philadelphia, Pa.), fume silicas and other fumed oxides, and
 particulate fillers), polymerizable monomers (e.g., isocyanates, polyols,
 silicones, acrylates) and crosslinkers (e.g., photoinitiators,
 thermalinitiators, catalysts and curing agents) may be employed with
 electrolytes used in the devices of this invention. The electrolyte may be
 converted to a polymeric solid after filling the cell with a liquid
 monomer composition or the two substrates may be laminated using a
 preformed electrolyte solid polymeric sheet. The solid electrolyte sheet
 can consist of the components described above. Such use is shown, for
 example, in the patents and patent applications incorporated by reference
 above.
 In the configurations of the EC devices of this invention utilizing one or
 more substrates, typical substrates used include glass, plastic, or metal.
 Substrates which are colored (either the glass substrates themselves are
 colored and/or have colored coatings underneath the transparent conductor)
 can also be used. Some examples of glass substrates include soda lime
 glass, borosilicate glass, AZURLITE glass, GL20 and GL35 (PPG Industries,
 Pittsburgh, Pa.), KRYSTAL KLEAR glass from (AFG Industries, Kingsport,
 Tenn.), and GALAXSEE and EZ-KOOL from Libbey Owens Ford (Toledo, Ohio).
 The coatings underneath the transparent conductor may also possess UV
 blocking characteristics as described in U.S. Pat. No. 5,859,722, which is
 incorporated by reference herein. Further, transparent conductors that may
 be used in the EC devices of this invention are well known. For example,
 indium/tin oxide coatings and fluorine doped tin or zinc oxide coatings
 can be used. Fluorine doped tin oxide coatings are available from Libbey
 Owens Ford (Toledo, Ohio) under the trade name of TEC, while fluorine
 doped zinc oxide coatings are described in International Patent
 Publication WO 98/08245. Colored glass such as TEC where color is imparted
 from either the bulk glass or from one of the coatings underneath the
 conductive coating can also be used as a substrate for these devices.
 In a similar aspect of this invention bleach speed is increased in EC
 devices having a layer composed of tungsten oxide, molybdenum oxide, or
 niobium oxide by adding at least one alkali metal oxide, M.sub.1, thereto.
 M.sub.1 is preferably chosen from Li, Na and K.
 Additionally, the doped layer of this invention can be formed from the
 composition described below to provide UV resistant properties to the EC
 layer. The UV resistant compositions can be utilized in EC device 900 in
 doped layer 902.
 Preferred compositions of UV resistant electrochromic layers of this
 invention may be selected from the following compositions:
EQU Composition 1: pM.sub.1 O+qM.sub.2 O+rM.sub.3 O (I)
EQU Composition 2: qM.sub.4 O+rM.sub.3 O (II)
 In the above compositions I and II:
 i) "O" means "oxide" and does not indicate any particular stoichiometry of
 oxygen relative to M.sub.1, M.sub.2, M.sub.3 and M.sub.4.
 ii) Ml is at least one of the alkali atoms chosen from Li, Na and K.
 iii) M.sub.2 is defined as those elements of Group 2A and those elements of
 the 4.sup.th period in a standard periodic table of the elements.
 Preferably, the oxides formed from the 4.sup.th period are those formed
 from elements having atomic number 45 (scandium) to atomic number 65
 (zinc). Preferably, the oxide from Group 2A is barium oxide. The most
 preferred oxides are those formed from the elements Ba, V, Cr, Co, and Cu.
 iv) M.sub.3 is at least one of W and Mo.
 v) M.sub.4 is Ba, Cr, Co, and Cu.
 For composition I, the atomic ratio of p to r ("p/r", the atomic ratio of
 M.sub.1 to M.sub.3) is in the range of from about 0.01 to about 2,
 preferably in the range of from about 0.1 to about 1. For compositions I
 and II, the atomic ratio (q/r) is in the range of from about 0.001 to
 about 0.5, preferably in the range of from about 0.01 to about 0.2. Other
 elements can be included in the above compositions (such as an oxide of
 another element not mentioned here) in addition to M.sub.1, M.sub.2,
 M.sub.3, and M.sub.4 but nevertheless the above defined atomic ratios will
 still hold. The above compositions are utilized as coatings that may be
 amorphous or crystalline, and may also be hydrated. Hydrated means that
 the composition contains OH groups and/or water.
 In one embodiment, referring to FIG. 9, an EC device 900 includes a doped
 layer 902 composed of such M.sub.1 doped tungsten or molybdenum oxide
 formed between a transparent conductor layer 901 and an EC layer 903 to
 reduce photochromism. EC layer 903 can be omitted, with doped layer 902
 then serving as a doped EC layer of this invention.
 The composition and/or microstructure of doped layer 902 can be different
 compared to EC layer 903. For example, layer 902 can be crystalline and
 layer 903 amorphous. Layers 902 and 903 may be processed differently to
 form a different crystal structure, density, amount of crystallinity, etc.
 As an example layer 902 may be processed in excess of 300.degree. C.
 whereas layer 903 is processed at lower temperatures to achieve the
 desired microstructure. The composition of doped layer 902 could be chosen
 from one of compositions 1 and 2 listed above, or could be any oxide
 (including mixtures of oxides) as long as one of the components in the
 layer is chosen from chromium oxide, cobalt oxide, barium oxide and copper
 oxide. The preferred range of thickness of doped layer 902 is between
 about 5 nm and about 100 nm, but any thickness which would lead to
 improved device performance can be used.
 The doped layer disclosed in this invention can be used in many different
 types of EC devices, such as i) those EC devices employing other redox
 promoters in the electrolyte as described in U.S. Pat. No. 5,724,187 which
 describes EC devices containing redox reaction promoters, and U.S. Pat.
 No. 4,671,619 which describes electrolytic solutions containing an iodide
 source material as a redox reaction promoter, and International
 Publication No. WO 97/38350 which describes an EC device containing a
 selective ion transport layer; ii) those EC devices having a
 counterelectrode but separated by an electrolyte as described in U.S. Pat.
 No. 5,708,523 which describes a counterelectrode containing a plurality of
 electrically conductive dots, and International Patent Publication Nos. WO
 97/22906 which describes an electrochromic element, and WO 95/31746 which
 describes an electrochromic pane arrangement; and iii) those EC devices
 that have all thin coatings only on one substrate as described in U.S.
 Pat. No. 4,712,879 which describes an EC mirror, International Patent
 Publication No. WO 94/15247 which describes EC devices utilizing optical
 tuning layers, and in S. P. Sapers, et al., "Monolithic Solid-State
 Electrochromic Coatings for Window Applications", Proceedings of the
 Society of Vacuum Coaters Conference 1996). All these references are
 incorporated herein by reference.
 Referring to FIG. 10, an EC device 1000 of this invention is shown which
 includes a transparent conductor 1001, an EC layer 1002, an electrolyte
 layer 1003, and an ion storage electrode 1004. Ion storage electrode 1004
 is also known as a counterelectrode. EC layer 1002 can be formed from, for
 example, tungsten oxide, molybdenum oxide, niobium oxide, or their
 mixtures.
 The counterelectrodes utilized by this invention are characterized by the
 following general formulas:
EQU xM.sub.5 O+yM.sub.6 O+zVO (III)
 and
EQU xM.sub.5 O+zVO (IV)
 where "O" indicates "oxide" of M.sub.5, M.sub.6 and vanadium and does not
 indicate any particular stoichiometry of oxygen relative to M.sub.5,
 M.sub.6, and V. These oxide compositions may or may not be hydrated.
 Hydrated means that they contain OH groups and/or water. M.sub.5
 represents at least one of the alkali elements in Group 1A of the periodic
 table (e.g., Li, Na, K, Rb, and Cs). M.sub.6 represents at least one of
 Ba, Ta, Cu, Nb, Re, Ti, Ce and Cr. The factors x, y, and z represent the
 stoichiometric relationship amongst these elements. Taking a ratio of one
 to another provides the atomic ratios of the associated term. For example,
 x/z provides the atomic ratio of M.sub.5 to V. For Composition IV, M.sub.5
 may not be sodium unless M.sub.5 is a mixture of oxides.
 Without being bound to the theory, it is believed that the addition of
 M.sub.5 improves the stability of the framework and opens the oxide
 network. Some of the preferred elements are lithium, sodium and potassium.
 These materials could be amorphous (including distorted octahedral and the
 framework structure) or could be micro-crystalline as measured by x-ray
 diffraction. It is preferred that the atomic ratio (x/z) range from about
 0.05 to about 1, and the ratio (y/z) range from about 0.1 to about 0.8.
 Other EC devices of this invention utilize counterelectrodes formed from
 compounds produced from a liquid phase chemical reaction. The compounds
 are described by the chemical formula:
EQU yM.sub.6 O+zVO (V)
 where M.sub.6 is Ta, Cr, Nb or Ti.
 Some of the compounds of equation (V) are described in U.S. Pat. No.
 4,938,571 utilized in an all solid-state EC device having a source of
 charge compensating ions and an inorganic counterelectrode. The patent,
 however, describes the use of a physical vapor deposition (PVD) process to
 form the compounds.
 In the present invention, by contrast, a wet-chemical route is utilized
 that forms the composition from a liquid phase reaction. The wet-chemical
 method is an advantageous route to deposit these yM.sub.6 O+zVO oxides, as
 well as other compositions disclosed herein, particularly because it is
 easier in the wet-chemical method to control the micro-structure, chemical
 composition and uniformity of the various metals in the coatings in order
 to form a coating having a morphology characterized by an amorphous or
 crystalline state including crystals less than 10 nanometers in size
 imbedded in an amorphous matrix. Further, depending on the details of the
 chemistry of the coating precursors and the processing conditions one
 could control porosity (thus the density and the refractive index) and
 structure (amorphous, microcrystalline, crystal size, etc.) of the
 coatings. The porosity is preferably about 5% to about 70%. Since many EC
 applications are for large area devices such as light filters (e.g., in
 displays), automobile and architectural glazing, this method can be used
 to process such coatings at a relatively small capital cost as compared to
 PVD.
 The porosity was established by measuring the thickness of the coating by a
 surface profilometer. The number of tungsten atoms per unit area were
 calculated from Rutherford back scattering (RBS). Percentage porosity was
 then calculated as the number of tungsten atoms per unit area divided by
 the number of tungsten atoms expected for a similar thickness 100%
 WO.sub.3 single crystal.
 Other elements (such as an oxide of another element not mentioned above)
 can be included in addition to M.sub.5, M.sub.6 and V in any of the above
 compositions (III), (IV), and (V). One could formulate counterelectrodes
 without departing from the teaching of this patent as long as vanadium
 concentration (atomic concentration based on total cations in the coating)
 in the counterelectrode coatings is greater than 35% and the atomic ratios
 of M.sub.5 to M.sub.6 ; M.sub.6 to V; and M.sub.5 to V are within the
 ranges disclosed above.
 The compositions of this invention reduce and/or change the yellow color
 typical of undoped vanadium oxide while still retaining durability
 maintaining or exceeding required electrochemical characteristics
 (cyclability, charge capacity, potentials for oxidation and reduction).
 These counterelectrodes have excellent optical properties, cyclability,
 charge capacity and are stable in both the reduced and the oxidized states
 for prolonged duration and within the environment that an EC device such
 as an automotive or architectural glazing may be subjected to.
 The counterelectrodes of this invention can be used for any electrochromic
 device where the coloration in the device is principally due to an EC
 layer (electrochromic electrode) that colors upon reduction (e.g.,
 intercalation by at least one of H.sup.+, Li.sup.+, Na.sup.+, etc., with a
 simultaneous injection of electrons). The counterelectrodes of this
 invention are particularly useful in EC devices that incorporate an
 electrochromic layer composed of tungsten oxide and/or molybdenum oxide at
 more than 20 mole %. The counterelectrodes can also be utilized in a
 variety of EC devices, including those in which other oxides are added to
 the tungsten oxide and/or molybdenum oxide to change the color, spectral
 characteristics, ion-insertion/extraction properties, color/bleach rates,
 reversibility, durability, etc of the EC device.
 Another embodiment of this invention is direct to counterelectrodes and
 electrochromic electrodes with dyes attached to inorganic oxides which can
 be used in the EC cells. For example, if tungsten oxide or any other
 cathodically coloring oxide (described previously) is used in an EC cell,
 the counterelectrodes can be anodic organic or metallorganic dyes which
 are put in an inorganic oxide host matrix. The dyes may modulate light in
 one of the ultraviolet, visible and infra-red spectrum of the solar
 radiation. Some example of dyes which modulate in the infrared are
 discussed in WO99/45081. These dyes may require further chemical
 modification to attach groups so that they can be anchored to the
 inorganic oxide surfaces. Such modification has been described and is
 known for other dyes. In principal all the inorganic oxide
 counterelectrodes described earlier in this disclosure can be used. The
 inorganic oxide matrices may be of single inorganic materials or mixtures.
 Some of the preferred inorganic oxides useful for housing anodic dyes are
 silicon oxide, titanium oxide, zirconium oxide, vanadium oxide, niobium
 oxide, nickel oxide, cobalt oxide, chromium oxide, cerium oxide, zinc
 oxide, aluminum oxide, tin oxide, indium oxide, antimony oxide, manganese
 oxide. These oxides may further be combined with oxides of alkali metals
 from Group 1 of the periodic table of elements. Electronically conductive
 oxides such as fluorine doped tin oxide, antimony doped tin oxide, tin
 doped indium oxide and aluminum doped zinc oxide can also be used. The
 conductivity of these oxides for dye interaction can range from 10,000
 ohms/.quadrature. to 1 ohm/.quadrature.. These electronically conductive
 oxides may be further deposited on pre-formed conductive substrates, or
 may be attached to the pores of the transparent conductor itself. Some
 transparent conductors with surface porosity are TEC 15 and TEC 8 from
 Libbey Owens Ford and Comfort E2 and TCO12 from AFG in Kingsport, Tenn.
 These counterelectrodes and electrochromic electrodes with dyes attached to
 inorganic oxides can be made in several ways. One could deposit the
 inorganic oxide coating first and then attach the inorganic dye on its
 surface by dipping these in solutions of organic dyes. Such methods are
 described in a solar cell, photochromic and electrochromic devices where
 ruthenium dyes or other dyes are attached to the titania substrates. See,
 e.g., M. K. Nazeeruddin, et al., J. Am. Chem. So., 115 (1993) 6382; U.S.
 Pat. No. 5,838,483 (G. Teowee et al); WO98/35267 (D. Fitzmaurice et al);
 and WO97/45767 (C. S. Bechinger et al.). To increase the surface area of
 attachment of the dyes, these coatings could be very porous. Preferred
 electrodes for transparent window applications should have low haze,
 preferably lower than 0.5% as measured by ASTM method D1003. A method to
 prepare and deposit transparent and porous titania coatings from colloidal
 solutions is outlined in U.S. Pat. No. 5,828,482 and in the "TiO.sub.2
 films for User Controlled Photochromic Applications" authored by T. J.
 Gudgel, et al in the Proceedings of the SPIE (Society of Photo Optical
 Instrumentation Engineers, Bellingham, Wash.) Vol. 3788 (1999) which are
 incorporated herein by reference. For many electrochromic devices (such as
 mirrors and glass for automotive applications) low haze is required,
 preferably below 2% and most preferably below 1% for the coated substrate.
 Typically several oxides, particularly when deposited from pre-fabricated
 particulates suspended in a liquid can result in substantial optical haze.
 However, the above deposition methods result in coatings which are very
 clear. The haze is typically measured using American Society for Testing
 and Materials (ASTM) method D1003. The measurement is made when the coated
 substrate is in contact with air. The measurement can be made before or
 after incorporating the dye. The haze should be low in both cases. For
 example, as given in the above reference from SPIE, a titania coating in a
 thickness of 240 nm was deposited from a colloidal solution containing
 pre-formed titania (anatase phase). This coating was deposited on a
 conductively coated glass substrate (TEC 15 from Libbey Owens Ford of
 Toledo, Ohio) and in contact with the conductive coating. The haze of the
 substrate before titania coating deposition was 0.53% and after coating
 0.27%. The measurement was made on a Hunterlab (Reston, Va.) spectrometer
 Colorquest II. In another method, a solution could be made which contains
 the precursor of the inorganic oxide. The dyes are either chemically
 attached to this precursor or dissolved in the solution. The coatings are
 formed by dipping, spraying or spinning these solutions on the substrates,
 followed by solvent evaporation. These coatings may further be heat
 treated to get rid of residual solvent and/or promoting further reactions.
 The coatings may even incorporate flexible groups which are polar so that
 good compatibility with the organic electrolytes is obtained. Such an
 exemplary moiety is polyethylene oxide.
 One may even assemble electrochromic devices using the electrochromic
 electrodes as described in WO98/35267, which for example are titania and
 other semiconductors with violgen bonded on to their surfaces. In this
 case the counterelectrode of the electrochromic device can be any of those
 described in this disclosure earlier which were suitable for tungsten
 oxide. Alternatively the counterelectrodes could be anodic polymers such
 as conductive polymers, e.g., polyaniline and its derivatives. Examples of
 other anodic polymers and the way to make electrochromic devices is
 described in WO96/13754 which is incorporated herein by reference. The
 major difference from WO96/13754 is that rather than including the
 cathodic compound in the electrolyte, the cathodic material (titania with
 violgen incorporation) is deposited as a coating on the conductive
 electrode counter to the polyaniline electrode. The anodic polymer may
 even be replaced by an anodic coloring oxide containing at least one of
 nickel oxide and vanadium oxide.
 The Examples which follow are intended as an illustration of certain
 preferred embodiments of the invention, and no limitation of the invention
 is implied.
 Improved Kinetics
 EXAMPLE 1, and COMATIVE EXAMPLES C1 and C2
 Device construction, 0.1 LiO+WO electrode and electrolyte:
 A 3 in..times.3 in. piece of conductive doped tin oxide coated glass
 (TEC8), available from Libbey Owens Ford (Toledo, Ohio), was coated with a
 thin film of 0.1 LiO+WO by a wet-chemical method described below. A
 tungsten peroxyester was prepared as described in U.S. Pat. No. 5,277,986,
 the disclosure of which is incorporated by reference herein. A coating
 solution was made by dissolving 350 g of the tungsten peroxyester
 precursor in 1 liter of reagent ethanol. After the precursor was
 completely dissolved, 4.82 g of lithium methoxide was added to the
 precursor solution to form a coating solution. The substrate was coated by
 dipping in the coating solution. The coating was then fired under humid
 conditions to 135.degree. C. as described in the U.S. Pat. No. 5,277,986.
 The coating thickness was between 450 to 500 nm.
 A portion of the fired coating was etched away from the conductive surface
 around the perimeter. This etched area was then primed with a silane or
 other equivalent organometallic containing primer to enhance adhesion with
 the glue as described later. Two holes about 0.125 inch (0.32 cm) in
 diameter were drilled in the opposite corners of a second 3 in..times.3
 in. (7.62 cm.times.7.62 cm) piece of TEC8 glass. The conductive surface
 around the perimeter of this second substrate was also etched and primed
 as described above.
 The cell was assembled by sealing these two substrates at the edges with an
 epoxy glue with their conductive coatings facing inward. The epoxy
 primarily touched the primed areas described above. As an alternative, the
 priming step could be omitted by adding the silane used in the primer
 directly to the epoxy glue. The spacing between the substrates was
 controlled by inserting 1 mm thick glass strips as spacers at the edges.
 The substrates, being of the same dimensions, were translated (shifted)
 relative to each other so as to be slightly offset thereby providing
 accessible areas to anchor electrical leads. The assembled substrates were
 clamped and the epoxy was cured thermally in an oven at 120.degree. C. for
 one hour in air. Several such cells were prepared without the electrolyte.
 The prepared cells were then filled with the liquid electrolytes shown in
 the table below. All percentages used herein are by weight unless
 specifically stated otherwise.

Comp. Ex. Com. Ex.
 Component C1 C2 Ex. 1
 Propylene Carbonate 59.04% 58.88% 58.88%
 Sulfolane 39.40% 39.34% 39.30%
 Lithium perchlorate 0.43% 0.42% 0.43%
 Ferrocene 0.15% 0.38% 0.38%
 Ferrocenium -- -- 0.03%
 hexafluorophosphate
 Deionized water 0.98% 0.98% 0.98%
 The filling holes were plugged with Teflon balls. The area around the plug
 hole was primed to enhance adhesion. A UV curable glue was poured on the
 plugs and covered with glass cover slides (which were also primed for
 improved adhesion). The glue was then cured by subjecting the plug area to
 UV radiation. Electrical wires were then soldered on to the offset areas
 formed as described above. The kinetic traces of these cells are shown in
 FIG. 2. The results show that Example 1 with the additive ferrocenium
 hexafluorophosphate bleached the fastest--faster than either Comparative
 Example C1 or C2.
 EXAMPLE 2 and COMATIVE EXAMPLE C3
 PSSNa overcoated 0.1 LiO+WO electrode:
 Devices similar to Example 1 were made, except that the 0.1 LiO+WO
 electrode was overcoated with a polystyrenesulfonate-sodium salt (PSSNa)
 coating. These devices are described in PCT application WO 97/38350. The
 PSSNa coating was deposited by spin coating a 5% solution (by weight) of
 500,000 molecular weight PSSNa in deionized (DI) water. A mixture of 1:1
 by weight of water and reagent ethanol optionally could be used instead of
 pure water. The PSSNa solution also contained 0.01% by weight of a
 surfactant Triton X100 (available from Aldrich Chemical Co., Milwaukee,
 Wis.). The PSSNa coating was also etched from the perimeter area prior to
 priming as described in Example 1. In these devices, hard rubber spacers
 rather than glass strips were used in the corners to control the gap
 between the substrates. The electrolyte compositions were:

Electrolyte Electrolyte
 composition composition
 for 210 micron for 850 micron
 electrolyte electrolyte
 thickness thickness
 Component Comp. Ex. C3 Ex. 2
 Propylene Carbonate 52.82% 53%
 Sulfolane 35.25% 35.3%
 Polymethyl methacrylate 9.76% 9.80%
 (PMMA) with an inherent
 viscosity of 1.38
 deciliter
 Lithium perchlorate 0.47% 0.47%
 Ferrocene 0.82% 0.41%
 Ferrocenium -- 0.02%
 hexafluorophosphate
 Deionized water 0.88% 1%
 FIG. 3 shows kinetic traces for the cells taken at 550 nm wavelength.
 Smaller gaps tend to produce faster kinetics than larger gaps. Example 2
 had a larger gap (850 micron electrolyte layer) than Comparative Example
 C3 (210 micron electrolyte layer). The results show that Example 2
 containing ferrocenium hexafluorophosphate nevertheless bleached with
 substantially similar kinetics to Comparative Example C3.
 EXAMPLE 3
 A 3 in..times.6 in. (7.62 cm.times.15.24 cm) device (similar in
 construction as described in Example 1) was constructed with uneven
 electrolyte spacing. The spacing (along the 3 inch (7.62 cm) edge) between
 the substrates at one end was 1.3 mm while the spacing was 0.7 mm at the
 other end. This was done by curing the epoxy seal in the cells with a
 thicker spacer at one end as compared to the other end.
 The device was filled with the following electrolyte:

Component Ex. 3
 Propylene Carbonate 53.14%
 Sulfolane 35.51%
 Polymethyl methacrylate 9.73%
 (PMMA) with an inherent
 viscosity of 1.38 deciliter
 Lithium Perchlorate 0.38%
 Ferrocene 0.24%
 Ferrocenium 0.02%
 hexafluorophosphate
 Deionized water 0.97%
 Example 3 only varied 2% in transmission of light at 550 nm wavelength from
 the example's thicker edge to its thinner edge. As shown in FIG. 4, there
 were virtually no differences in the kinetics and in the light
 transmission of the colored state among the different gap thicknesses (1.3
 mm, 1.0 mm, and 0.7 mm). Thus, although Example 3 had large variations in
 the thicknesses of the electrolyte layer, the resulting variation of the
 depth of coloration and kinetics with thickness was advantageously
 negligible.
 As describe previously, such variations in thickness can be caused in
 practice by non-uniformity in the substrates used. If strengthened or
 tempered glass substrates are used, for example, they might not be flat
 enough to maintain a uniform gap. As another example, substrates that are
 bent to form a curved cell might not be perfectly matched in curvature,
 leading to electrolyte gap variations. Thus, as shown by the results of
 Example 3, this invention can prevent variations in EC cell gap
 (electrolyte thickness) from affecting cell optical and kinetic
 properties.
 EXAMPLES 4A, 4B, 4C, 4D, and COMATIVE EXAMPLE C4
 Several devices were fabricated similar to that described in Example 1. The
 substrates used were ITO coated soda-lime glass (12 ohms/sq.). The
 electrolyte composition in the cells were as formed from the following
 constituents:

Electrolyte Comp. Ex.
 component Ex. C4 Ex. 4A 4B Ex. 4C Ex. 4D
 Propylene carbonate 44.92% 44.88% 44.84% 44.77% 44.69%
 Sulfolane 31.76% 31.73% 31.71% 31.65% 31.60%
 Poly- 7.56% 7.55% 7.54% 7.53% 7.52%
 methylmethacrylate** 0.47% 0.47% 0.47% 0.47% 0.47%
 Ferrocene 0.59% 0.59% 0.58% 0.58% 0.58%
 Ferrocenium 0.00% 0.09% 0.17% 0.34% 0.51%
 tetrafluoroborate
 Lithium perchlorate 0.07% 0.07% 0.07% 0.07% 0.07%
 Lithium 0.24% 0.24% 0.24% 0.24% 0.23%
 tetrafluoroborate
 Tetrabutylammonium 10.37% 10.36% 10.35% 10.33% 10.31%
 tetrafluoroborate
 Uvinul 3000* 4.04% 4.03% 4.03% 4.02% 4.02%
 Bleach speed 0.55 0.77 1.05 2.0 2.72
 (% T/sec)
 *Uvinul 3000 is a UV stabilizer available from BASF Corp. (Parsippany, NJ).
 **PMMA - had a Mw of 463,000 and Mn of 167,000
 The modulation kinetics of each device for light at 550 nm wavelength are
 shown in FIG. 5a. The figure shows that the kinetics are faster with
 increasing ferrocenium tetrafluoroborate concentration. As seen in FIG.
 5b, the bleaching rate also increases with increasing ferrocenium
 tetrafluoroborate concentration.
 UV Durable
 EXAMPLE 5
 Formation of coating precursors:
 Examples 5-17 used EC coatings deposited by a wet-chemical method, similar
 to that described above in Example 1, by dissolving 350 g of the tungsten
 peroxyester precursor in 1 liter of reagent ethanol, adding 4.82 g of
 lithium methoxide to the precursor solution, and stirring at room
 temperature for two hours to form the coating solution. This amount of
 lithium corresponded in p/r of 0.1. This quantity of lithium methoxide can
 be adjusted proportionally to provide different p/r ratios.
 The coatings were deposited onto conductive transparent substrates such as
 ITO or TEC glass by spin, dip or roller coating. The thickness of the
 coatings were varied between 10 and 1000 nm. Preferably, the thickness of
 the coatings was about 500 nm.
 Each coating was then fired under humid conditions to 135.degree. C. as
 described previously. In the Examples, coatings heated to higher
 temperatures were first subjected to the humid treatment at 135.degree. C.
 The subsequent higher temperature treatments were then conducted in a
 standard atmosphere unless otherwise specified.
 EXAMPLE 6
 A tungsten/copper oxide coating was prepared having the composition
 Cu.sub.0.064 W.sub.0.93 O.sub.y by adding 9 g of peroxotungstic ethoxide
 to 30 ml of dry ethanol and 0.198 g of copper(II) methoxide. The mixture
 was stirred at room temperature for two hours to complete dissolution. The
 resulting solution was a light green color which was spin coated under
 ambient atmosphere onto 2 inches.times.2 inches (5.1 cm.times.5.1 cm) ITO
 coated glass substrates at 1200 rpm.
 The coated substrate was then heated under humid conditions to 135.degree.
 C. The thickness of the resulting coating was 350 nm. The charge capacity
 was determined in a three electrode cell configuration where the
 counterelectrode was platinum, the reference electrode was Ag/AgNO.sub.3
 and the electrolyte was 0.1 molar LiClO.sub.4 in propylene carbonate. From
 an insertion step potential of 1.3 volts the charge capacity was
 determined to be 1,005 C.multidot.cm.sup.-3. Under this degree of
 reduction the coating had a % T of 19.7% for light at 550 nm wavelength.
 EXAMPLE 7
 A tungsten oxide coating containing potassium having the composition
 K.sub.0.1 W.sub.0.9 O.sub.y was prepared by reacting 0.28 g of potassium
 ethoxide with 9.0 g of peroxotungstic ethoxide in 30 ml of dry ethanol.
 The mixture was dissolved by being sonicated at about 40.degree. C. for 30
 minutes and then stirred at room temperature for twelve hours. The
 solution was filtered using a 0.1 micron filter and spin coated at 1000
 rpm onto 3 inches.times.3 inches (7.6 cm.times.7.6 cm) ITO coated glass
 substrates and fired under humid conditions to 135.degree. C. The
 thickness of the resulting coating was 415 nm. The coating had 84% T for
 light at 550 nm wavelength. When colored at a step potential of 1.3 volts,
 as described in Example 6, the % T was 8.8 for 550 nm light.
 EXAMPLE 8
 A tungsten oxide coating containing sodium having the composition
 Na.sub.0.1 W.sub.0.9 O.sub.y was prepared by reacting 0.23 g of sodium
 ethoxide with 9.0 g of peroxotungstic ethoxide in 30 ml of dry ethanol.
 The mixture was stirred at room temperature for twelve hours to form a
 clear yellow solution. The solution was filtered using a 0.1 micron filter
 and spin coated at 1000 rpm onto 2 inches.times.2 inches (5.1 cm.times.5.1
 cm) ITO coated glass substrates and fired under humid conditions to
 135.degree. C. The thickness of the resulting coating was 330 nm. For
 light at 550 nm wavelength, the coating had a % T of 78. When colored at a
 step potential of 1.3 volts, as described in Example 6, its % T was 14 for
 light at 550 nm.
 EXAMPLE 9
 A tungsten oxide coating containing lithium having the composition
 Li.sub.0.1 W.sub.0.9 O.sub.y was prepared by reacting 0.13 g of lithium
 methoxide with 9.0 g of peroxotungstic ethoxide in 30 ml of dry ethanol.
 The mixture was stirred at room temperature for two hours to form a clear
 yellow solution. The solution was filtered using a 0.1 micron filter and
 spin coated at 500 rpm onto 2 inches.times.2 inches (5.1 cm.times.5.1 cm)
 ITO coated glass substrates and fired under humid conditions to
 135.degree. C. The thickness of the resulting coating was 550 nm. The
 coating had an 84% T for light at 550 nm wavelength. When colored at a
 step potential of 1.3 volts, as described in Example 6, its % T was 3 for
 light at 550 nm.
 EXAMPLE 10
 A tungsten oxide coating containing barium having the composition
 Ba.sub.0.1 WO.sub.0.9 O.sub.y was prepared by dissolving 9.0 g of
 peroxotungstic ethoxide in 30 ml of dry ethanol. To this solution, at room
 temperature, was added 0.45 g of barium metal. The mixture was stirred for
 twelve hours to produce a clear yellow solution. The solution was filtered
 with a 0.2 micron filter and spin coated at 1000 rpm onto 2 inches.times.2
 inches ITO coated glass substrates. The coating was fired under humid
 conditions to 135.degree. C. The resulting coating was 450 nm thick. Under
 a step potential of 1.3 volts, as described in Example 6, the charge
 capacity of the coating was determined to be 9,956 C.multidot.cm.sup.-3.
 Under the 1.3 v. degree of reduction, the % T was 18.8 for light at 550 nm
 wavelength.
 EXAMPLE 11
 Fabrication of Cells
 The experiments below, to Example 18, were conducted on cells that employed
 a redox promoter in the electrolyte. The cells consisted of EC windows
 fabricated using two substrates coated with a transparent conductor that
 was either Indium/Tin Oxide (available from Applied Films, Boulder, Co.)
 or TEC glass (available from Libbey Owens Ford, Toledo, Ohio). In each of
 the cells, one of the substrates was further coated with tungsten oxide
 before being assembled into the cell. The cells were produced by a process
 similar to that described above in Example 1.
 EXAMPLES 12A and 12B
 Lithium and lithium copper doped tungsten oxide precursor solutions were
 prepared by dissolving 100 g of PTE and 1.3671 g of lithium methoxide in
 250 ml of ethanol. For the copper doped solution 0.4139 g of copper
 methoxide was added. Coatings were fabricated as described in Example 5.
 The cells were made as described in Example 11 and their stability to UV
 is described in the Table below. The electrolyte composition was propylene
 carbonate and sulfolane (in a ratio of 60:40 by volume) in which 1 molar
 lithium perchlorate and 10 wt % polymethylmethacrylate were added.
 Other electrolyte compositions can be used containing other additives such
 as, for example, different lithium and sodium salts, water, UV
 stabilizers, colorants, pigments and different polymers, as known in the
 art. Further, an in-situ polymerizable composition as is also known in the
 art can also be used. These additives can influence the UV properties as
 tested in this and other examples. However, the improvement of UV
 properties as demonstrated in the Examples would still be observed even
 with different electrolyte.
 The cells were exposed to solar radiation and their optical transmission of
 light at 550 nm wavelength were measured periodically. The results below
 show that the addition of copper substantially reduced the detrimental
 photochromic effect.

Bleached transmission (% @ 550 nm)
 Hours Ex. 12A [EX. 12B]
 exposed to (0.3 Li, 0.01 Cu, W)O.sub.y (0.3 Li, W)O.sub.y
 UV (Processed at 250.degree. C.) (Processed at 250.degree. C.)
 0 83.2 81.3
 6 82.4 70.9
 20 - - - 64.8
 28 82.0 - - -
 60 - - - - - -
 the ratios described above are atomic ratios
 Further, the coatings without copper, but containing higher amounts of
 lithium were less photochromic.
 EXAMPLES 13A, 13B, 13C, and COMATIVE EXAMPLE C5
 Electrochromic cells with tungsten oxide coatings of various compositions
 were made as described in Example 1. The electrode coatings were
 fabricated as described in Example 5 except that a thin layer of
 copper-containing WO.sub.3 was first deposited on the ITO surface. The
 CU/WO.sub.3 coatings were prepared as described in Examples 12A and 12B
 and had a thickness of 20 nm after being fired. On top of this thin
 coating was deposited a lithium-containing WO.sub.3 coating formed in a
 manner as described in Example 5. The specific details of each Example are
 listed in the Table below. The coatings were incorporated into
 electrochromic cells as described in Example 12 and the cells tested under
 UV exposure.

Comp. Ex.
 C5 Ex. 13A Ex. 13B Ex. 13C
 Thin None (Cu.sub.0.02 WO.sub.0.98) (Cu.sub.0.01 WO.sub.0.99)
 (Cu.sub.0.01 WO.sub.0.99)
 layer O.sub.y O.sub.y O.sub.y
 between 135.degree. C. 135.degree. C. 250.degree. C.
 EC
 layer
 and
 ITO
 surface
 EC (Li.sub.0.1 WO.sub.0.9) (Li.sub.0.1 WO.sub.0.9)O.sub.y (Li.sub.0.3
 WO.sub.0.7)O.sub.y (Li.sub.0.3 WO.sub.0.7)O.sub.y
 Layer O.sub.y
 135.degree. C. 135.degree. C. 250.degree. C. 250.degree. C.
 Thickness Thickness Thickness Thickness
 450 nm 420 nm 665 nm 595 nm
 Hours % T % T % T % T
 exposed (550 nm) (55O nm) (550 nm) (550 nm
 to
 UV
 0 79.3 84.6 82.3 82.7
 6 59.2 - - - 76.6 77.32
 8 - - - 81.0 - - - - - -
 28 39.7 - - - 70.3 71.5
 32 - - - 75.3 - - - - - -
 The results show that the Examples 13A, 13B, and 13C, with the thin coating
 of copper-containing tungsten oxide had an effective resistance to change
 when subjected to UV. Additionally, the surfaces of the underlying
 coatings can also provide other advantages over the prior art such as
 improved adhesion and better control of interfacial stress. The thin coat
 can also minimize changes in EC coating thickness during processing,
 particularly when wet-chemical methods are used to deposit the coats.
 EXAMPLES 14A, 14B, 14C, and 14D
 In these Examples 14A, 14B, 14C, and 14D, tungsten oxide coatings were
 prepared containing A) barium oxide, B) potassium oxide, C) lithium oxide
 and D) copper oxide as described in Examples 10, 7, 9 and 6, respectively.
 The coatings were incorporated into cells as described in Example 12. The
 cells were exposed to solar radiation and the change in transmission of
 light at 550 nm wavelength were recorded as a function of time as listed
 in Table 3 below:
 TABLE 3
 Ex. 14A Ex. 14B Ex. 14C Ex. 14D
 (Ba.sub.0.1 W.sub.0.9) (K.sub.0.1 W.sub.0.9) (Li.sub.0.1
 W.sub.0.9) (Cu.sub.0.1 W.sub.0.9)
 Cell Type O.sub.y O.sub.y O.sub.y O.sub.y
 Time % T at 550 nm
 Exposed to
 UV
 (hours)
 0 83 82 80 75
 16 73 66 70 73
 56 67 59 62 71
 The results all show resistance to UV induced deterioration of light
 transmittance. Example 14D, with the copper-containing tungsten oxide, had
 the best resistance to transmittance change when subjected to UV
 radiation.
 EXAMPLE 15
 An electrochromic coating having a composition (Li.sub.0.1 Cr.sub.0.1
 W.sub.0.8)O.sub.y was prepared by first reacting 0.696 g of chromium(II)
 acetate monohydrate in 20 ml of ethanol with 4 ml of 30 wt % H.sub.2
 O.sub.2 at 0.degree. C. The product was isolated under vacuum at
 60.degree. C. and dissolved in 30 ml of ethanol. To this solution, 10.2 g
 of peroxotungstic ethoxide and 0.16 g of lithium methoxide were added. The
 solution was filtered using a 0.2 micron filter and resulted in a stable
 precursor solution which could be used under ambient conditions. The
 solution was spin coated at 500 rpm onto 3 inches.times.3 inches (7.6
 cm.times.7.6 cm) ITO and fired to 135.degree. C. under humid conditions.
 The resulting fired coating thickness was 661 nm.
 EXAMPLE 16
 An electrochromic coating having a composition (Li.sub.0.1 Co.sub.0.1
 W.sub.0.8)O.sub.y was prepared by reacting 0.922 g of cobalt(II) acetate
 tetrahydrate in 30 ml of ethanol with 10.2 g of peroxotungstic ethoxide
 and 0.16 g of lithium methoxide. The solution was filtered using a 0.2
 micron filter and resulted in a stable precursor solution which could be
 used under ambient conditions. The solution was spin coated at 500 rpm
 onto 2 inches.times.2 inches (5.1 cm.times.5.1 cm) ITO and fired to
 135.degree. C. under humid conditions. The resulting fired coating
 thickness was 710 nm.
 EXAMPLE 17
 The optical and electrochromic properties of coatings having the
 compositions (Li.sub.0.1 Cr.sub.0.1 W.sub.0.8)O.sub.y and (Li.sub.0.1
 Co.sub.0.1 W.sub.0.8)O.sub.y, prepared in Examples 15 and 16, were
 compared with those of a (Li.sub.0.1 W.sub.0.9)O.sub.y coating prepared as
 described in Example 9 by preparing cells in accordance with the technique
 described in Example 7 and the testing thereof. The data is summarized in
 Table 4 below. Also included in the table are the solar radiation exposure
 data for the (Li.sub.0.1 W.sub.0.9)O.sub.y and the (Li.sub.0.1 Cr.sub.0.1
 W.sub.0.8)O.sub.y coatings. The coatings were colored under a step
 potential of 1.2 volts as described in Example 6.
 TABLE 4
 Light Transmission as
 a function of UV
 1931 2.degree. CIE standard Exposure
 illuminant A Time
 (eye response) exposed to % T at (550
 Coating Colored Bleached UV (hours) nm)
 (Li.sub.0.1 W.sub.0.9 O).sub.y 9.2 81.0 0 78
 62 50
 110 47
 (Li.sub.0.1 Cr.sub.0.1 W.sub.0.8)O.sub.y 6.6 80.2 0
 78
 62 68
 110 63
 (Li.sub.0.1 Co.sub.0.1 W.sub.0.8)O.sub.y 6.7 80.0
 The data in Table 4 show that, by adding Co and Cr to the EC coating, the
 optical modulation of the devices is were not reduced. Further, these
 coatings were incorporated in EC cells as described in Example 12 and
 exposed to UV. Further, the Cr-containing coating showed better resistance
 to change in LTV compared to the unadulterated (Li.sub.0.1 Cr.sub.0.1
 W.sub.0.9)O.sub.y coating. FIG. 11 illustrates the voltage generated by
 the EC cell when subjected to the radiation of specific wavelengths. The
 results set forth in FIG. 11 show that the EC cell with chromium doped
 tungsten oxide is less sensitive to higher ultraviolet wavelengths as
 compared to the non-doped sample.
 EXAMPLE 18
 A tungsten oxide coating containing lithium was prepared as described in
 Example 5 except that the p/r was 0.5. After being fired under humidity,
 the resulting coating was again fired to 250.degree. C. under ambient
 atmosphere. The resulting twice fired (under higher temperature) coating
 was incorporated into a cell configuration as described in Example 1. The
 transmission, for light at 550 nm wavelength, through the device was 73%.
 When colored for 100 seconds at 1.3 v the light transmission was 16.5%.
 The cell under a potential of zero volts bleached back to 73% T in 300
 seconds. In the colored state the device had a neutral gray color. The
 transmission spectra of the cell in the colored and bleached state is
 shown in FIG. 6. Also shown in FIG. 6 is the colored spectrum for a cell
 containing Li/WO.sub.3 with a p/r of 0.3. This cell when colored was blue.
 Zirconium oxide has been added to tungsten oxide to impart neutral color in
 the colored state. Typical atomic concentration of Zr/W is less than 0.15
 (WO99/08153). However, increasing concentration of Zirconium (within the
 above range) leads to a dramatic loss in the extent of coloration. It has
 been discovered that the addition of Zirconium along with alkali metal
 oxides of Li, Na and K result in novel compositions of open oxide networks
 which color well and also have a neutral gray color. These compositions
 can be further modified by adding M.sub.2 as shown for composition 1 to
 enhance UV stability (i.e., M.sub.3 oxide is a mixture of tungsten and
 zirconium oxides). Of course, addition of M.sub.4 as in composition 2,
 where only W and Zr oxide mixtures are used can also result in enhancing
 the UV stability. Along similar lines novel combinations can be formed
 when zirconium is substituted in part or completely by vanadium. In
 WO97/22906 it was shown that the combination of tungsten and vanadium
 oxides also color to a neutral gray color.
 Counterelectrodes
 EXAMPLE 19
 A vanadium oxide coating was prepared by dissolving 5 ml of vanadium
 triisopropoxide oxide, [(CH.sub.3).sub.2 CHO].sub.3 VO, in 50 ml of
 isopropanol under dry nitrogen. The solution was stirred for twelve hours
 and spin coated onto ITO coated glass with a sheet resistance of
 12.OMEGA./p. The coating was heat treated at a heating rate of 5.degree.
 C./minute to 250.degree. C. The resulting coating was amorphous and yellow
 in color. A 125 nm thick coating had a 50% transmission for light at 550
 nm wavelength. Lithium was inserted into the coating under potential
 limits of -1 to 2 volts with respect to Ag/AgNO.sub.3 reference electrode.
 The electrolyte was 0.01 molar LiClO.sub.4 in propylene carbonate. Under
 these conditions the charge capacity was calculated to be 1,180
 C.multidot.cm.sup.-3.
 EXAMPLE 20
 A vanadium oxide coating was prepared as described in Example 19 except
 that the coating was fired to 350.degree. C. in a second firing. This
 resulted in a crystalline coating that was yellow in color. From a current
 versus voltage plot, between the potential limits of -1 and 2 volts, at a
 scan rate of 10 mV/s, the apparent charge capacity was calculated to be
 2,242 C.multidot.cm.sup.-3. The coating showed a slight electrochromic
 behavior on insertion and/or extraction of lithium.
 EXAMPLE 21
 A metal oxide coating (xLi+zV)O was prepared. The molar ratio of lithium to
 vanadium was 0.54. The ((Li.sub.0.35 V.sub.0.65)O.sub.y coating was
 prepared by adding 40 ml of isopropyl alcohol, 2 ml of 2,4-pentanedione,
 and 5 ml of vanadium triisopropoxide oxide to a flask under nitrogen. The
 mixture was stirred at room temperature for one hour. Then, 1.18 g of
 lithium 2,4-pentanedione was added. The solution was heated to 40.degree.
 C., and 1 ml of glacial acetic acid was added, to form the spin deposition
 solution.
 The resulting solution was spin coated onto ITO coated glass and heated to
 250.degree. C. under ambient atmosphere. From a current versus voltage
 analysis, between the potential limits -1 and 2 volts, at a scan rate of
 0.1 mV/s, the charge capacity was determined to be 3,900
 C.multidot.cm.sup.-3.
 EXAMPLE 22
 A coating was prepared as described in Example 21 except that the sodium
 alkali metal ion was used instead of lithium. The (Na.sub.0.35
 V.sub.0.65)O.sub.y coating was prepared by dissolving 5 ml of vanadium
 triisopropoxide oxide and 2.06 ml of 2,4-pentanedione in 60 ml of
 isopropyl alcohol. The mixture was allowed to react for 1 hour and 0.253 g
 of sodium metal was added. This resulted in a vigorous reaction with the
 evolution of hydrogen gas. The reaction was completed in about one hour
 and the mixture was left to stand under nitrogen for 24 hours. The
 solution was spin coated onto ITO coated soda-lime glass substrate and
 fired to 250.degree. C. for one hour. The fired coating on the substrate
 was colorless and had a % T value of 65 as measured against standard
 Illuminant A and a solar % T air mass 2 (AM2) value of 49. On insertion of
 lithium, the coating changed from colorless to light brown. The charge
 capacity was calculated to be 13,700 C.multidot.cm.sup.-3.
 EXAMPLE 23
 A potassium vanadate coating was prepared by reacting 2.9 ml of vanadium
 triisopropoxide oxide, with 1 g of potassium acetate, in 50 ml of a 50/50
 mixture of ethanol and isopropyl alcohol at 60.degree. C. under nitrogen.
 The mixture was stirred for 48 hours. Then 8 ml of glacial acetic acid was
 added and the mixture heated at 70.degree. C. for 30 minutes. This
 resulted in a light green clear solution which was deposited by spin
 coating onto ITO.
 The coating was fired to 350.degree. C. for one hour in air. The heating
 rate was 5.degree. C./minute. The resulting coating thickness was 70 nm.
 The coating was colorless and had a slight brown tint in the reduced
 state. The charge capacity of the coating was determined under cyclic
 voltammetry at two different scan rates between the potential limits of
 -1.2 to 2.5 volts. The reference electrode was Ag/AgNO.sub.3 and the
 counterelectrode was Pt. The electrolyte was 0.1 molar LiClO.sub.4 in
 propylene carbonate. At a scan rate of 10 mV/s the charge capacity was
 1,893 C.multidot.cm.sup.-3, while the charge capacity was 3,694
 C.multidot.cm.sup.-3 at 2 mV/s.
 EXAMPLE 24
 A coating was prepared as described in Example 21 except that barium was
 used as the additive material. The (Ba.sub.0.35 V.sub.0.65)O.sub.y coating
 was prepared by reacting 2.88 g of barium metal with 60 ml of dry ethanol.
 The reaction was vigorous with the evolution of hydrogen gas. On cessation
 of gas evolution, 8 ml of vanadium triisopropoxide oxide and 2 ml of
 N-dimethyl formamide was added. The mixture was heated to 60.degree. C.
 for 30 minutes and cooled to room temperature to produce a clear orange
 solution. This solution was spin coated onto ITO coated substrate and
 heated to 250.degree. C. under ambient atmosphere for one hour. The
 resulting fired coating was slightly brown in color. Its charge capacity
 was calculated to be 961 C.multidot.cm.sup.-3.
 EXAMPLE 25
 A thin film coating of composition (Nb.sub.0.35 V.sub.0.65)O.sub.y was
 prepared by dissolving 5 ml of vanadium triisopropoxide oxide and 4.09 ml
 of 2,4-pentanedione in 60 ml of isopropyl alcohol. The mixture was allowed
 to react for 1 hour and then 3.53 ml of niobium (V) ethoxide was added to
 produce a clear red solution. After spin deposition on ITO, the coating
 was fired to 250.degree. C. for one hour under ambient atmosphere. The
 coating had a slight yellow tint and a charge capacity of 1,000
 C.multidot.cm.sup.-3.
 EXAMPLE 26
 A niobium vanadate thin film was prepared as described in Example 24 except
 that the coating was fired to 350.degree. C. for one hour under ambient
 atmosphere. The coating had a slight yellow tint. Under lithium insertion,
 the coating had a charge capacity of 1,055 C.multidot.cm.sup.-3 and was
 highly reversible.
 EXAMPLE 27
 A niobium vanadate coating with a Nb/V ratio equal to one (unity) was
 prepared by reacting vanadium triisopropoxide oxide with niobium (V)
 chloride in dry isopropyl alcohol. 25.5 g of niobium chloride was slowly
 added to 250 ml of isopropyl alcohol while stirring under nitrogen. The
 mixture was stirred for two hours and 22.8 ml of vanadium triisopropoxide
 oxide added. This resulted in a red solution. The solution was heated at
 60.degree. C. under nitrogen for 48 hours resulting in a green solution.
 This solution was filtered through a 0.1 micron filter and spin coated
 onto an ITO coated substrate. The coating was fired to 250.degree. C.
 under an ambient atmosphere for one hour at a heating rate of 10.degree.
 C./min. The resulting coating on the substrate appeared colorless and had
 a thickness of 190 nm. The charge capacity for lithium insertion was
 determined to be 1,360 C.multidot.cm.sup.-3.
 EXAMPLE 28
 A niobium vanadate coating (y:z=1) solution was prepared as described in
 Example 27 except that, after heating at 60.degree. C. for 48 hours, NaOH
 dissolved at varied concentrations in ethanol was slowly added to the
 green solution. This resulted immediately in a white precipitate (composed
 substantially of NaCl) and a more basic pH.
 The resulting solutions were filtered and spin coated onto ITO substrates
 and fired to 250.degree. C. for one hour at a heating rate of 10.degree.
 C./minute under ambient air. The coatings appeared colorless on the
 substrate with an 86% transmission of light at 550 nm wavelength.
 Depending on the amount of chlorine removed from the solution (in the form
 of sodium chloride) through the addition of NaOH the charge capacity of
 the coating could be optimized. The electrolyte was 0.4 molar LiClO.sub.4
 in propylene carbonate.
 TABLE 5
 NaOH 0.0 0.3 0.4 0.45 0.5 0.55 0.6
 (Molar)
 Thickness 190 130 110 100 85 80 70
 (nm)
 Charge 1,360 1,400 1,850 1,960 1,960 1,920 910
 Capacity
 (C .multidot. cm.sup.-3)
 EXAMPLE 29
 An electrochromic transmissive device was fabricated using a NbVO.sub.y
 coating prepared as described in Example 27, with a thickness of 250 nm,
 as the counterelectrode. The working electrode WO.sub.3 used was deposited
 by a wet-chemical method. The precursor (tungsten peroxyester) for this
 was prepared as described in U.S. Pat. No. 5,277,986, the disclosure of
 which is incorporated by reference herein.
 The coating solution was made by dissolving 350 g of the precursor in 1
 liter of reagent ethanol. The coatings contained lithium which was added
 in the form of lithium methoxide to the precursor solution. When the
 precursor was completely dissolved, 4.82 g of lithium methoxide was added
 and stirred at room temperature for two hours to form the coating
 solution. This amount of lithium corresponded to a W/Li of 0.1. The
 coatings were deposited onto ITO substrates fired under humid conditions
 to 135.degree. C. as described above. The LiWO.sub.3 thickness was 450 nm.
 The fired coating thickness was between 450 to 500 nm. A cell was then
 made out of the two electrodes by etching the coating from the conductive
 surface around the perimeter. This area was then primed with a silane
 primer to enhance adhesion with the glue as described below.
 Two holes about 0.125 inch (0.32 cm) in diameter were drilled in opposite
 corners of the 3 in..times.3 in. (7.62 cm.times.7.62 cm) NbVO.sub.y coated
 substrate. Prior to cell assembly, the NbVoy electrode was reduced with
 lithium in a two or three electrode cell configuration. Alternative
 reducing methods as described in U.S. Pat. No. 5,780,160, incorporated
 herein by reference, can be used. The methods include, for example,
 in-situ reduction by the electrolyte, in-situ reduction in the cell prior
 to the introduction of the electrolyte, and reduction while depositing the
 coating.
 In this example, electrochemical reduction was by a nickel electrode in a
 bath filled with 0.4 molar LiClO.sub.4 in propylene carbonate. The
 NbVO.sub.y was reduced with 0.9 coulombs of lithium. A cell was assembled
 by sealing the NbVO.sub.y and LiWO.sub.3 coated substrates, with coatings
 facing inward, at the edges with an epoxy glue. The epoxy primarily
 touched the primed areas described above.
 The spacing between the substrates was controlled by inserting 53 micron
 spacers in the sealing epoxy. The substrates, having the same dimensions,
 were slightly offset to provide a place to anchor the electrical leads.
 The substrates were clamped and the epoxy was cured at 25.degree. C. for
 one hour in air.
 The cells were filled with an electrolyte composed of 0.01 molar
 LiClO.sub.4 in propylene carbonate. Other additives such as UV
 stabilizers, fillers, polymers, and monomers, for example, optionally
 could also be added to the electrolyte. Many such additives are described
 in patent application EP 0612826A1. After filling, the filling holes were
 plugged with Teflon balls. The area around the plug hole was primed with a
 methacrylic based silane primer to enhance adhesion. A UV curable glue was
 poured on the plugs and covered with glass cover slides (which were also
 primed for improved adhesion). The glue was then cured by subjecting the
 plug area to UV radiation at 8 W/cm.sup.2 for 30 seconds. Electrical wires
 were then soldered on to the offset areas described above.
 The cell was colored by applying a coloring potential of 1.2 volts. The
 transmission of light at 550 nm went from 60.5% to 9.4% in 90 seconds and,
 by applying a bleaching potential of -1.2 volts, it went back to 60.5 % T
 in 120 seconds.
 EXAMPLE 30
 A vanadium oxide thin film containing tantalum was prepared with a
 tantalum/vanadium ratio of 0.54. The (Ta.sub.0.35 V.sub.0.65)O.sub.y
 coating was prepared by reacting 5 ml of vanadium triisopropoxide oxide
 with 4.13 ml of 2,4-pentanedione and 2.88 ml of tantalum (V) ethoxide in
 isopropyl alcohol. The mixture was stirred at room temperature under dry
 nitrogen for one hour and spin coated onto ITO coated glass substrates.
 The inorganic oxide network was formed by heating to 250.degree. C. for
 one hour under ambient atmosphere. The film was 140 nm thick and 50%
 transmitting for light at 550 nm wavelength. Its charge capacity was
 calculated to be 407 C.multidot.cm.sup.-3.
 EXAMPLE 31
 A coating composed of (Ta.sub.0.35 V.sub.0.65)O.sub.y was prepared as
 described in Example 30 with the exception that the coating was heated to
 350.degree. C. for one hour under ambient atmosphere. The coating had a
 solar % T (AM2) equal to 48%. The coating had light brown color. Under
 lithium insertion the coating had a charge capacity of 2,067
 C.multidot.cm.sup.-3.
 EXAMPLE 32
 A rhenium vanadate coating was prepared, having a molar ratio of Re to V
 equal to 0.25, by first reacting 8 g of rhenium metal with a 50/50 mixture
 of H.sub.2 O.sub.2 (30 vol %) and glacial acetic acid at 0.degree. C. The
 resulting mixture was allowed to react for 90 minutes. The reaction
 mixture was then slowly warmed to room temperature and reacted for an
 additional 24 hours. The excess hydrogen peroxide and acetic acid were
 removed under reduced pressure at 60.degree. C. to leave a yellow liquid
 of the rhenium complex. The rhenium complex was added to an isopropyl
 alcohol solution of vanadium triisopropoxide oxide such that the molar
 concentration of rhenium was 20%. The resulting solution was spin coated
 onto an ITO coated substrate and fired by being heated to 200.degree. C.
 for one hour under ambient atmosphere. The thickness of the fired coating
 was 120 nm. The coating was light green in color and had a charge capacity
 of 965 C.multidot.cm.sup.-3.
 EXAMPLE 33
 A copper(II) vanadate film was prepared, having a molar ratio of Cu to V
 equal to 0.54, by dissolving 3.54 g of copper(II) n-butyrate in 80 ml of
 dry isopropyl alcohol and then adding 3.28 g of vanadium triisopropoxide
 oxide and 1 g of water. The solution was stirred under nitrogen at room
 temperature for 12 hours prior to spin coating onto conductive tin oxide
 coated glass. The coating was fired to 350.degree. C. for one hour under
 ambient atmosphere. The thickness of the coating was 146 nm. The charge
 capacity for lithium insertion at a scan rate of 0.1 mV/s was calculated
 to be 2,186 C.multidot.cm.sup.-3.
 EXAMPLE 34
 A ferrocene counterelectrode was prepared as follows. Ferrocene was
 dilithiated with 2 equivalents of n-butyl lithium in presence of
 tetramethylene diamine for 12 hours at room temperature. The reaction was
 quenced with an excess of trimethoxychlorosilane. The crude product was
 dissolved in methanol, the solution was filtered, and thin films were spun
 on TEC20 substrates. Condensation was believed to proceed according to
 Scheme 1, and was performed by first exposing the films to HCl, gas for 3
 hours and then heating the films for one day at 80-100.degree. C.
 ##STR1##
 The cyclic voltammetry of these films (100 nanometers) showed a
 well-defined redox wave at +1.0 V vs. Ag/AgCl in PC 1M LiTfO.
 One cell was made with LTW03 and a Fc counterelectrode. The initial
 modulation was from 70% to 30% T, and the kinetics was very fast.
 EXAMPLE 35
 Ferrocene counterelectrodes were prepared by reacting functionalized
 ferrocene in a sol-gel network. Two functionalized ferrocenes were
 prepared: a silyated material containing alkoxysilane groups and ferrocene
 carboxylic acid.
 (a) SILYLATED FERROCENE
 Silylated ferrocene was prepared by the following reaction:
EQU Fc--CH.sub.2 OH+(EtO).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2
 NCO.fwdarw.Fc--CH.sub.2 OCONHCH.sub.2 CH.sub.2 CH.sub.2 Si (OEt).sub.3
 Ferrocenemethanol was refluxed with a slight excess of
 3-(triethoxysilyl)propyl isocyanate (1 ferrocene: 1.05 isocyanate molar
 ratio) in MEK for 90 minutes. After this time, the solvent was stripped
 off in a rotary is evaporator to yield a brown liquid. FTIR analysis
 indicated that the reaction was complete by the disappearance of the --Oh
 and --NCO bands and the appearance of the urethane band.
 The silyated ferrocene was incorporated into a base matrix of PEG.sub.4
 /LiClO.sub.4 /ZrO.sub.2. Prior to reaction, the PEG.sub.4 was also
 silyated with 3-(triethoxysilyl)propyl isocyanate as described above for
 the ferrocene methanol:
EQU HO--[CH.sub.2 CH.sub.2 O].sub.4 --H+2(EtO).sub.3 SiCH.sub.2 CH.sub.2
 CH.sub.2 NCO
EQU .dwnarw.
EQU (EtO).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2 NHCOO--[CH.sub.2 CH.sub.2 O].sub.4
 --CONHCH.sub.2 CH.sub.2 CH.sub.2 Si (OEt).sub.3
 A coating solution was prepared by the following reaction scheme:
EQU Fc--CH.sub.2 OCONHCH.sub.2 CH.sub.2 CH.sub.2 Si (OEt).sub.3 /MeOH
EQU H.sub.2 O/H+.dwnarw.
 silylated PEG.sub.4.dwnarw.
EQU H.sub.2 O/H+.dwnarw.
EQU Zr(O.sup.n Pr).sub.4 /HOAc.dwnarw.
EQU LiClO.sub.4.dwnarw.
 The resulting solution was then spin coated on TEC 15 at various speeds,
 followed by curing at 125.degree. C. for 30 minutes. Films up to .about.4
 micrometers were obtained after curing. These films were fabricated into
 EC cells with WO.sub.3 as an electrochromic electrode. Tungsten oxide was
 deposited by a dip process onto a TEC 15 substrate. The cell was
 fabricated as described in earlier examples. The electrolyte thickness of
 the EC cells was 210 microns. The electrolyte consisted of 50.6% propylene
 carbonate, 35.8% sulfolane, 9% polymethylmethacrylate, 3-5% UVinul 3000,
 0.7% water, 0.3% LiBF.sub.4 and 0.1% LiClO.sub.4 by weight.
 Thinner films (0.65 and 0.13 .mu.m) with a longer cure (125.degree. C./8
 hrs) were also prepared. These were much harder and stable in the
 electrolyte compared to using the milder cure conditions. They colored at
 .about.2.5V but only with a limited degree of modulation. The high
 voltages required to color these films indicated that the poor
 conductivity of the matrix was the major problem. To investigate this,
 similar films were deposited on a porous conducting undercoat.
 The undercoat was a sol-gel derived Sb--SnO.sub.2 coating deposited on TEC
 15. Two different spin-coating speeds were used to obtain thinner and
 thicker films. The ferrocene counterelectrode was then deposited on top to
 give the following configuration:
 Ferrocene/Porous SnO.sub.2 Counterelectrode

ferrocene film
 porous SnO.sub.2
 TEC 15
 glass
 These film configurations colored at 1.3 V. The films had low leakage
 currents of approximately 0.5 mA, indicating that the ferrocene had been
 successfully immobilized.
 (b) CHELATED FERROCENE FILMS
 A ferrocene carboxylic acid--Zr alkoxide counterelectrode was prepared.
 This material is based on the chelation of the ferrocene carboxylic acid
 to Zr n-propoxide as shown below:
 ##STR2##
 Coating solutions were prepared by refluxing ferrocene carboxylic acid and
 Zr n-propoxide, at 1:1 and 1:2 molar ratios of Zr:Fc, in MEK. Films were
 then spin coated on TEC 15 and cured at 125.degree. C. for 8 hours. The
 resulting coatings, up to 1 .mu.m thick, were hard and stable in the
 electrolyte and colored at 1.3 V.
 Other variations and modifications of this invention will be apparent to
 those skilled in this art after careful study of this application. This
 invention is not to be limited except as set forth in the following
 claims.