WO1995013311A2

WO1995013311A2 - Capped compounds for solid polymeric electrolytes

Info

Publication number: WO1995013311A2
Application number: PCT/US1994/012978
Authority: WO
Inventors: Benjamin Chaloner-Gill; Milton Neal Golovin; Joseph Lundquist
Original assignee: Valence Technology, Inc.
Priority date: 1993-11-10
Filing date: 1994-11-10
Publication date: 1995-05-18
Also published as: AU1053995A; WO1995013311A3

Abstract

Polymer precursors for the solid polymer matrix of a solid polymeric electrolyte are capped polyester or poly(alkylene oxide) poly(oxyalkylene) units. The capping groups are selected from carbonate, phosphate, phosphonate, siloxy and sulfone groups.

Description

CAPPED COMPOUNDS FOR SOLID POLYMERIC ELECTROLYTES

FIELD OF THE INVENTION

The invention relates to polymers for solid polymeric electrolytes and their use in solid electrochemical cells. The invention particularly relates to polymer precursors for single-phase, solid polymeric electrolytes.

BACKGROUND OF THE INVENTION

Solid electrolytes have been shown to have many advantages in the fabrication of electrochemical cells and batteries, such as thermal stability, reduced corrosion of the electrodes, and cyclability. Furthermore, solid electrolytes permit us to create electrochemical sources of high energy-per-unit weight. Solid electrolytes, particularly polymeric electrolytes, have the principal advantage of being prepared in thin layers which reduces cell resistance and allows large drains at low current densities. In the design of solid polymeric electrolytes both the properties of ionic conductivity and mechanical strength must be provided. It has been found advantageous to incorporate inorganic ion salts and solvents into the solid electrolytes, as well to select polymers which enhance ionic conductivity. Cross-linking of the polymers can lead to stronger solid electrolytes, i.e. resilient thin layers of electrolyte, but cross-linking must not be to the detriment of ionic conductivity. Radiation has been extensively used to induce cross- linking.

Poly (alkylene oxide) derivatized with acryloyl and/or urethane groups, is a polymer precursor for single-phase, radiation-cured polymeric electrolytes. However, the radiation-cured solid polymer electrolyte may lack sufficient mechanical strength and toughness or may be too brittle. U.S. Patent 4,830,939 discloses a solid electrolyte which is a radiation polymerized network interpenetrated by an ionically conducting liquid.

Solid polymeric electrolytes are formed from monomers or prepolymers containing hetero atoms (particularly oxygen and nitrogen atoms) capable of forming donor acceptor bonds with an alkali metal cation. Such polymer precursors are polyethylenically unsaturated compounds terminated by radiation-polymerizable moieties. For example, consider the polymer precursor A-(CH₂CHRO)„-A, wherein R is hydrogen or an alkyl group of from 1 to 3 carbon atoms, and A is an ethylenically unsaturated moiety or glycidyl moiety. A particularly useful group of radiation-polymerizable compounds is disclosed as the reaction product of a polyethylene glycol with acrylic or methacrylic acid. The disclosure of U.S. Patent 4,830,939 is incorporated herein by reference in its entirety.

Fiona M. Gray, in "Solid Polymer Electrolytes", VCH Publishers, New York, 1991, the disclosure of which is incorporated herein by reference in its entirety, disclosed poly(ethylene glycol) and siloxane-based solid polymer electrolytes, pp. 98-102; urethane-linked poly(ethylene glycol) solid polymeric electrolytes, pp. 99-103; and phosphate ester poly(ethylene glycol), p. 103. U.S. Patent 4,792,504 discloses an electrolyte which is poly(ethylene oxide) cross-linked by a polyacrylate. U.S. Patent 4,357,401 disclosed polymers and other oligomers which upon cross-linking form an ionically conducting macromolecular material of low glass transition temperature which is diisocyanate-linked. The disclosure of each patent is incorporated herein by reference in its entirety. While the urethane linkages have heretofore been used to cross-link polymer matrices for solid polymeric electrolytes, it is recognized that urethanes can be mechanically strong but too brittle. Furthermore, the urethanes contain a relatively active hydrogen bound to nitrogen, i.e. abstractable and acidic, which may react with the anodic metal.

For these reasons it would be advantageous if cross-linking and/or capping groups were found for the solid polymer matrix which provide the properties needed by solid polymeric electrolytes while alleviating these problems.

U.S. Patent No. 5,262,253 is incorporated herein by reference in its entirety. It discloses a poly(alkylene glycol) capped with at least one vinyl sulfonate group, i.e. -OSO₂CR=CH₂, and which may also be capped with a hydrocarbyl group, an ethylenically unsaturated moiety or a glycidyl residue. The capped materials find use as polymer precursors for radiation-cured solid polymeric electrolytes.

SUMMARY OF THE INVENTION

The present invention is directed, in part, to the discovery of novel compounds which are capped polyesters or poly(alkylene glycols), (i.e. polymer precursors) and which are readily polymerized. The polymer precursors of this invention are represented by Formula I: I. A-[Z„ X R²]-,.

wherein Z_B is - ( CH∑ CHRⁱ O jn - or - (R* 0C(0)R6 c( 0 )0 )_n - wherein R¹ is selected from the group consisting of hydrogen and an alkyl group of from 1 to 3 carbon atoms; A is selected from the group consisting of a hydrocarbyl group of from 1 to about 30 carbon atoms, a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms and a glycidyl residue; n is an integer from about 2 to about 50; R² is selected from the group consisting of hydrocarbyl of from 1 to 30 carbon atoms, and a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms; X is selected from the group consisting of 0 o carbonate - c H-₀ — phosphate P n-0 —

I o

R4

0 0 phosphonate P-0— , sul f one — s — 0- ,

I II

R* 0

R3

I si l oxy — — Si-0 — I

R4

wherein R³ and R⁴ are hydrocarbyl or oxyhydrocarbyl groups of from 1 to about 7 carbon atoms; R^s is a hydrocarbylene or oxyhydrocarbylene group of from 1 to 12 carbon atoms; R⁶ is a hydrocarbylene group of from 1 to 12 carbon atoms; and m is an integer from 1 to about 50, preferably from 1 to about 3, and more preferably 1. In said polymer precursor, R¹ is preferably hydrogen and n is preferably an integer between 2 and about 20, more preferably an integer of about 10, and A is preferably an acryloyl moiety.

When polymerized these compounds form a polymer suitable for use as a solid matrix in a solid polymeric electrolyte. Accordingly, in another of its compositional aspects, this invention is directed to a single-phase, solid, solvent-containing electrolyte which comprises: a solid polymeric matrix; an inorganic ion salt; and a solvent; wherein said solid polymeric matrix is obtained by polymerizing a polymer precursor represented by Formula I. In another of its compositional aspects the present invention is directed to an electrochemical cell which comprises: an anode comprising a compatible anodic material, a cathode comprising a compatible cathodic material; and interposed therebetween a single-phase, solid, solvent-containing electrolyte which comprises: a solid polymeric matrix; an inorganic ion salt; and a solvent; wherein the polymeric matrix is obtained by polymerizing a polymer precursor represented by Formula I.

In yet another aspect of the present invention, a battery comprises at least two of the aforementioned electrochemical cells.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides a solid polymeric matrix and polymer precursors for the production of a solid polymeric matrix. The polymeric precursors are the reaction product of poly(alkylene glycol) with reactants which provide "capping" groups. However, prior to describing this invention in further detail, the following terms will first be defined.

Definitions

As used herein the following terms have the following meanings.

The term "solid single-phase polymeric electrolyte" and "solid polymeric electrolyte" refer to an ionically conducting solid, normally comprising an inorganic ion salt, a compatible electrolyte solvent, and a solid polymeric matrix.

The term "solid polymeric matrix" refers to a solid polymer formed by polymerizing a monomer, a polymer precursor, or prepolymer, which matrix is preferably ionically conducting. The term "polymer precursor", or "prepolymer", refers to compound of substantial molecular weight greater than

300 and preferably greater than 500, which undergoes crosslinking reactions when "cured". The polymer precursor contains at least one heteroatom capable of forming a donor-acceptor bond with inorganic cations derived from inorganic ion salts under conditions such that the resulting polymer is useful in preparing solid polymeric electrolytes. Solid polymeric matrices are well known in the art and are described, for example, in U.S. Patents 4,908,283 and 4,925,751, both of which are incorporated herein by reference in their entirety.

The term "capping" groups for "capped" polyester and polyoxyalkylene chains refers to the replacement of terminal OH groups by chemical groups capable of cross-linking. The cross-linking groups are ethylenically unsaturated groups located near the terminus of the polyoxyalkylene chains. The solid polymeric matrix of the present invention is derived from the novel polymer precursors of the present invention by cross-linking (curing) the components of the polymer precursor. Such cross-linking or curing is achieved chemically and is induced by thermal means or by actinic radiation, preferably by actinic radiation. "Actinic radiation" refers to any radiation or paniculate beam having the ability to induce the desired chemical reaction. Consequently, the actinic radiation is of an energy content which is appropriate to the desired reaction. In the practice of the present invention the use of electron beam generators and ultraviolet light sources, well known to the art, produce actinic radiation of appropriate energy to cure an electrolyte mixture comprising a solid electrolyte polymer precursor. The optimum degree of cross-linking is dictated by a balance of the properties required in a solid polymeric electrolyte, such as, mechanical strength, ionic conductivity, and solvent electrolyte retention without separation. The term "compatible electrolyte solvent" or in the context of components of the solid electrolyte, "solvent" is a low molecular weight plasticizer added to the electrolyte and/or the cathode composition which may also serve the purpose of solubilizing the inorganic ion salt. The solvent is any compatible, volatile, aprotic, relatively polar, solvent. Preferably, these materials have boiling points greater than about 80° C. to simplify manufacture and increase the shelf life of the electrolyte/battery. Typical examples of solvent are mixtures of such materials as propylene carbonate, ethylene carbonate, γ-butyrolactone, tetrahydrofuran, glyme, diglyme, triglyme, tetraglyme and dimethyl sulfoxide, dioxolane, sulfolane, and the like. A particularly preferred solvent is disclosed in U.S. Patent 5,262,253 which patent is incorporated herein by reference in its entirety. A distinction is made in the art between those solid electrolytes which contains a low molecular weight solvent and those which do not; Gray, "Solid Polymer Electrolytes", ibid., pages 1-2 and 108-109.

The term "hydrocarbyl" and "hydrocarbylene" refer to monovalent and divalent organic radicals composed of carbon and hydrogen which may be aliphatic, alicyclic, aromatic, or combinations thereof, e.g. aralkyl. Examples of hydrocarbylene groups include alkylene, such as ethylene, propylene, hexamethylene and the like, arylene, such as phenylene, naphthalene, and the like, hydrocarbyl groups include alkyl, such as methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, heptyl octyl, and the like, alkenyls, such as propenyl, isobutenyl, hexenyl, octenyl, and the like, aryl, such as phenyl, alkylphenyl, including 4-methylphenyl, 4-ethylphenyl, and the like. Likewise, oxyhydrocarbyl refers to hydrocarbyl radicals containing minor amounts of oxygen, such as alkoxy, e.g., ethoxyethyl, propoxyethyl, and the like. And likewise, oxyhydrocarbylene refers to hydrocarbylene groups containing minor amounts of oxygen, such as oxyalkylene, e.g., oxyethylene, oxypropylene, poly(oxyalkylene), poly(oxyethylene) and the like.

The term "acryloyl-derivatized" refers to a molecule containing the acryloyl group, herein represented by A. For purposes of the present invention the preferred acryloyl group has the chemical formula CH₂=CR^*C(O)-, wherein

R¹ is H or a C,-C₃ alkyl. However, acrylates are preferred over methacrylates.

The term "a compatible ethylenically unsaturated moiety of from 2 to about 6 carbon atoms" refers to unsaturated moieties attached to the polyester or poly (alkylene oxide) chain through a suitable linking group. Examples of compatible ethylenically unsaturated moieties include the aforementioned acryloyl group; a vinyl group, CH₂=CH-; allyl, CH₂=CH-CH₂-; more generally, allyl derivatives CH₂=CH(CH₂)_p-, where p is an integer from 1 to 5, and the like.

The term "glycidyl residue" refers to oligomeric derivatives of glycerol, (HOCH₂CHOH CH₂OH), which have a poly(alkylene oxide) moiety attached to at least one of the oxygen atoms of the hydroxyl groups by replacement of the proton of the hydroxyl group. For example,

( -CH2 CHO- )k I CH2 -O-

where k is an integer from 1 to about 10. Additionally, included with the term glycidyl are glycidyl moieties wherein one or more of the carbon atoms of the glycidyl moiety are substituted with an alkyl group of from 1 to 4 carbon atoms.

The term "salt" refers to any inorganic salt which is suitable for use in a solid electrolyte, for example, an inorganic ion salt. The particular inorganic ion salt employed is not critical and examples of suitable inorganic ion salts include, by way of example, LiClO₄, Lil, LiSCN, LiBF₄, LiAsF₆, LiPF₆, Nal, NaSCN, KI, LiSO₃CF₃, AgNO₃, CuCl₂, and the like. The inorganic ion salt preferably contains at least one atom selected from the group consisting of Li, Na, and K.

The term "electrochemical cell" refers to a composite structure containing an anode, a cathode and an ion-conducting electrolyte interposed therebetween.

The term "anode" refers to the electrode in an electrochemical cell at which oxidation occurs on discharge. It is typically comprised of a compatible anodic material, i.e. any material which functions as an anode in a solid electrochemical cell. Such compatible anodic materials are well known in the art and include, by way of example, lithium, lithium alloys, such as alloys of lithium with aluminum, mercury, iron, zinc, and the like, and intercalation anodes, such as carbon, tungsten oxides and the like.

The term "cathode" refers to the counterelectrode to the anode. It is typically comprised of a compatible cathodic material, e.g. an insertion compound which is any material which functions as a cathode in an electrochemical cell. Such compatible cathodic materials are well known to the art, and include, by way of example, manganese oxides, molybdenum oxides, vanadium oxides such as V₆O₁₃, sulfides of molybdenum, titanium and niobium, chromium oxides, lithiated cobalt oxides, lithiated nickel oxides, copper oxides and the like. The particular compatible cathodic material employed is not critical.

In an embodiment of the present invention a hydroxy-terminated polyester or poly (alkylene glycol) is reacted with one of the following: acrylic acid, acrylic acid chloride, alkenoic acid, methacrylic acid, glycidol acrylate, glycidyl methacrylate, glycerol, a glycidol polymer, or a vinyl glycidyl ether.

The free OH groups of the polyester or polyoxyalkylene chain may be further reacted with alkylene oxides, preferably ethylene oxide, using for example a basic or acidic catalyst to form side chains.

However, it is an element of the present invention that at least one of the free OH groups is capped with a capping group selected from the group consisting of phosphate, phosphonate, siloxy, sulfone, and carbonate.

The capping group, herein represented by XR², contains a substituent, R², which is selected from the group consisting of compatible ethylenically unsaturated moieties, of from 2 to about 10 carbon atoms, and hydrocarbyl groups of from 1 to 30 carbon atoms.

Thus, in the present invention, at least one of the polyester or polyoxyalkylene chains in the polymer precursor contains a compatible ethylenically unsaturated moiety, preferably near the chain terminus. The unsaturation may be provided by the capping group substituent, R². The number average molecular weight of the compound of Formula I ranges from about 1,000 to about 100,000; preferably from about 1,000 to about 50,000; more preferably from about 2,000 to about 30,000 and most preferably from about 2,000 to about 10,000.

METHODOLOGY

Methods for preparing the solid polymeric matrix and the solid polymeric electrolyte are well known in the art. However, the present invention utilizes a particular polymer precursor in the preparation of a solid polymeric matrix. The solid polymer precursor is at least one capped polyester or polyoxyalkylene chain. The capping reactions, well known to those of ordinary skill in the art, are illustrated by the following reactions. The carbonate-capped polymer precursor may be obtained by the reaction of a polyester or polyoxyalkylene chain terminal hydroxy group(s) with a acid chloride, as in Reaction 1.

A[ ( -CH₂ CHRi O- )n-H ]« + Cl C ( 0 )OR2

A[ ( -CH2 CHR1 0- )_n -C ( 0 ) OR2 ]m + HCl

A, R¹ and R² have been heretofore defined, m is an integer having a value from 1 to 50, more preferably from 1 to 3 and most preferably 1. This synthesis avoids the reversibility associated with esterification. The hydrogen chloride may escape as such, or it may be absorbed in a base such as triethylamine, sodium hydroxide, ^N,N- dimethylaniline, or pyridine. The simplest procedure consists in shaking the acid chloride with aqueous base containing the appropriate alcohol. For best yields the acid chloride and ester formed should be insoluble in water so that the reaction occurs at the interface of the organic and aqueous layers. The insolubility of the ester in the aqueous phase retards its saponification. At the end of the reaction the ester is free from acid chloride and hydrogen chloride and can be extracted and dried immediately by conventional means. See CA. Buhler and D.E. Pearson, "Survey of Organic Synthesis", Wiley, New York, 1970, the disclosure of which is incorporated herein by reference in its entirety.

The phosphonate-capped polymer precursor may be obtained from the reaction of the polyester or polyoxyalkylene terminal hydroxyl(s) with a dihydrocarbyl chlorophosphinate as illustrated in Reaction 2.

2 .

A[ ( -CH₂ CHR1 0- )n -H ]» + Cl P ( 0 ) OR2 R4 ^■>

A[ ( -CH₂ CHR1 0- )n -P ( 0 ) OR2 R4 ]_B + HC1

The phosphate-capped polymer precursor is obtained from the reaction of the polyester or polyoxyalkylene terminal hydroxyl(s) with a dihydrocarbyl chlorophosphonate i.e. representing the case when OR² and R⁴ represent alkoxy groups. By reaction with thionylchloride, SOCl₂, the chlorophosphinate, and the chlorophosphonate are obtained from the corresponding phosphinate and phosphonate. The synthesis of these compounds by this and other means has been disclosed in H.D. Orloff, J. Amer. Chem. Soc. 8_Q, 727 (1958); U.S. Patents 2,409,039; 2,426,691; 2,478,441; A.W. Frank et al., J. Org. Chem. 21, 872 (1966); J.F. Allen et al., J. Amer. Chem. Soc. 78, 3715

(1956); British Patent 783,697; A.E. Arbuzov et al., J. Russ. Phys. Chem. Soc. 62, 1533 (1930); B. Ackerman et al. J. Amer. Chem. Soc. 7 , 6524 (1957); G.M. Kosolapoff, "Organophosphorus Compounds", Wiley, New York, 1950; J.R. Van Wazer, "Phosphorous and Its Compounds", Wiley, New york, 1961; and CR. Noller, "Chemistry of Organic Compounds", pp. 317-323,

Saunders, Philadelphia, 1965; the disclosure of each of the foregoing references is incorporated herein.

The siloxy-capped polymer precursor may be obtained by the reaction of the polyester or polyoxyalkylene chain terminating hydroxyl(s) with a monochlorosilane. The reactions of silanes and their preparation are known in the art, see for example C Eaborn, "Organosilicon Compounds", Academic Press, New York, 1960; R.N. Meals et al., "Silicones", Reinhold, New York, 1959; W. Noll, "Chemistry and Technology of Silicones", Academic Press, New York, 1968; CG. Freeman, "Silicones: An Introduction to Their Chemistry and Applications", ILIFFE, London, 1962; and E.G. Rochow, "An Introduction to the Chemistry of Silicones", Second Edition, Wiley- Interscience, New York, 1951. The disclosures of the foregoing references are incorporated herein. The sulfone-capped polymer-precursor may be obtained from the reaction of halided alcohol with sodium hydrocarbyl sulfonate R²SO₂Na. First, the alcohol is converted to the tosyl derivative with p-toluenesulfonylchloride. Then the tosyl-derivative is converted to the halide by, for example, lithium chloride in ethanol. See M.F. Clarke et al., J. Chem. Soc. 215, 226 (1949), the disclosure of which is incorporated herein by reference. The halide is converted to the sulfone by reaction with the sulfonate. See Noller, "Chemistry of Organic Compounds", pp. 312-313, Saunders, Phila., 1965, the disclosure of which is incorporated herein by reference in its entirety.

Example

The solid electrolyte and the electrochemical cell are prepared as described in the following example wherein a commercially available urethane polymer precursor, is used as the polymer precursor for a polymeric matrix analogous to that of the present invention. While urethane acrylate of the following example is not based upon the principle of capping-groups of the present invention, the preparation of a solid electrolyte by curing a polymer precursor of the present invention is substantially the same.

A solid electrolytic cell is prepared by first preparing a cathodic paste which is spread onto a current collector and is then cured to provide for the cathode. An electrolyte solution is then placed onto the cathode surface and is cured to provide for the solid electrolyte composition. Then, the anode is laminated onto the solid electrolyte composition to provide for a solid electrolytic cell. The specifics of this construction are as follows:

A. The Current Collector The current collector employed is a sheet of aluminum foil having a layer of adhesion promoter attached to the surface of the foil which will contact the cathode so as to form a composite having a sheet of aluminum foil, a cathode and a layer of adhesion promoter interposed therebetween.

Specifically, the adhesion promoter layer is prepared as a dispersed colloidal solution in one of two methods. The first preparation of this colloidal solution for this example is as follows:

8.44 weight percent of carbon powder

(Shawinigan Black™ — available from Chevron Chemical Company, San Ramon, CA) 33.76 weight percent of a 25 weight percent solution of polyacrylic acid (a reported average molecular weight of about 90,000, commercially available from Aldrich Chemical Company — contains about 84.4 grams polyacrylic acid and 253.2 grams water) 57.80 weight percent of isopropanol

The carbon powder and isopropanol are combined with mixing in a conventional high shear colloid mill mixer (Ebenbach-type colloid mill) until the carbon is uniformly dispersed and the carbon particle size is smaller than 10 microns. At this point, the 25 weight percent solution of polyacrylic acid is added to the solution and mixed for approximately 15 minutes. The resulting mixture is pumped to the coating head and roll coated with a Meyer rod onto a sheet of aluminum foil (about 9 inches wide and about 0.0005 inches thick). After application, the solution/foil are contacted with a Mylar wipe (about 0.002 inches thick by about 2 inches and by about 9 inches wide — the entire width of aluminum foil). The wipe is flexibly engaged with the foil (i.e., the wipe merely contacted the foil) to redistribute the solution so as to pro-vide for a substantially uniform coating. Evaporation of the solvents (i.e., water and isopropanol) via a conventional gas-fired oven provides for an electrically- conducting adhesion-promoter layer of about 6 microns in thickness or about 3 x 10"* grams per cm². The aluminum foil is then cut to about 8 inches wide by removing approximately ^lή inch from either side by the use of a conventional slitter so as to remove any uneven edges.

In order to further remove the protic solvent from this layer, the foil is redried. In particular, the foil is wound up and a copper support placed through the roll's cavity. The roll is then hung overnight from the support in a vacuum oven maintained at about 130°C Afterwards, the roll is removed. In order to avoid absorption of moisture from the atmosphere, the roll is preferably stored into a desiccator or other similar anhydrous environment to minimize atmospheric moisture content until the cathode paste is ready for application onto this roll.

The second preparation of this colloidal solution comprises mixing 25 lbs of carbon powder (Shawinigan Black™ ~ available from Chevron Chemical Company, San Ramon, CA) with 100 lbs of a 25 weight percent solution of polyacrylic acid (average molecular weight of about 240,000, commercially available from BF Goodrich, Cleveland, Ohio, as Good-Rite K702 - contains about 25 lbs polyacrylic acid and 75 lbs water) and with 18.5 lbs of isopropanol. Stirring is done in a 30 gallon polyethylene drum with a gear- motor mixer (e.g., Lightin Labmaster Mixer, model XJ-43, available from Cole-Parmer Instruments Co., Niles, Illinois) at 720 rpm with two 5 inch diameter A310-type propellers mounted on a single shaft. This wets down the carbon and eliminates any further dust problem. The resulting weight of the mixture is 143.5 lbs and contains some "lumps".

The mixture is then further mixed with an ink mill which consists of three steel rollers almost in contact with each other, turning at 275, 300, and 325 rpms respectively. This high shear operation allows particles that are sufficiently small to pass directly through the rollers. Those that do not pass through the rollers continue to mix in the ink mill until they are small enough to pass through these rollers. When the mixing is complete, the carbon powder is completely dispersed. A Hegman fineness of grind gauge (available from Paul N. Gardner Co., Pompano Beach, FL) indicates that the particles are 4-6 μm with the occasional 12.5 μm particles. The mixture can be stored for well over 1 month without the carbon settling out or reagglomerating.

When this composition is to be used to coat the current collector, an additional 55.5 lbs of isopropanol is mixed into the composition working with 5 gallon batches in a plastic pail using an air powered shaft mixer (Dayton model 42231 available from Granger Supply Co., San Jose, CA) with a 4 inch diameter Jiffy-Mixer brand impeller (such as an impeller available as Catalog No. G-04541-20 from Cole Parmer Instrument Co., Niles, Illinois). Then, it is gear pumped through a 25 μm cloth filter (e.g., So-Clean Filter Systems, American Felt and Filter Company, Newburgh, NY) and Meyer-rod coated as described above.

B. The Cathode

The cathode is prepared from a cathodic paste which, in turn, is prepared from a cathode powder as follows: i. Cathode Powder The cathode powder is prepared by combining 90.44 weight percent

V₆O₁₃ [prepared by heating ammonium metavanadate (NH^VO/) at 450°C for 16 hours under N₂ flow] and 9.56 weight percent of carbon (from Chevron Chemical Company, San Ramon, CA under the tradename of Shawinigan Black™). About 100 grams of the resulting mixture is placed into a grinding machine (Attritor Model S-l purchased from Union Process, Akron, Ohio) and ground for 30 minutes. Afterwards, the resulting mixture is dried at about 260°C for 21 hours. ii. Cathode Paste

A cathode paste is prepared by combining sufficient cathode powder to provide for a final product having 45 weight percent V₆O₁₃. Specifically, 171.6 grams of a 4: 1 weight ratio of propylene carbonate:triglyme is combined with 42.9 grams of polyethylene glycol diacrylate (molecular weight about 400 available as SR-344 from Sartomer Company, Inc., Exton, PA), and about 7.6 grams of ethoxylated trimethylolpropane triacylate (TMPEOTA) (molecular weight about 450 available as SR-454 from Sartomer Company, Inc., Exton, PA) in a double planetary mixer (Ross #2 mixer available from Charles Ross & Sons, Company, Hauppag, New York).

A propeller mixer is inserted into the double planetary mixer and the resulting mixture is stirred at a 150 rpms until homogeneous. The resulting solution is then passed through sodiated 4 A molecular sieves. The solution is then returned to double planetary mixer equipped with the propeller mixer and about 5 grams of polyethylene oxide (number average molecular weight about 600,000 available as Polyox WSR-205 from Union Carbide Chemicals and Plastics, Danbury, CT) is added to the solution vortex from by the propeller by a mini-sieve such as a 25 mesh mini-sieve commercially available as Order No. 57333-965 from VWR Scientific, San Francisco, CA.

The solution is then heated while stirring until the temperature of the solution reaches 65 °C At this point, stirring is continued until the solution is completely clear. The propeller blade is removed and the carbon powder prepared as above is then is added as well as an additional 28.71 grams of unground carbon (from Chevron Chemical Company, San Ramon, CA under the tradename of Shawinigan Black™). The resulting mixture is mixed at a rate of 7.5 cycles per second for 30 minutes in the double planetary mixer. During this mixing the temperature is slowly increased to a maximum of 73 °C At this point, the mixing is reduced to 1 cycle per second the mixture slowly cooled to 40°C to 48°C (e.g. about 45°C). The resulting cathode paste is maintained at this temperature until just prior to application onto the current collector. The resulting cathode paste has the following approximate weight percent of components: V₆O₁₃ 45 weight percent

Carbon 10 weight percent 4:1 propylene carbonate/tri- glyme 34 weight percent polyethylene oxide 1 weight percent polyethylene glycol diacrylate 8.5 weight percent ethoxylated trimethylol- propane triacrylate 1.5 weight percent

In an alternative embodiment, the requisite amounts of all of the solid components are added to directly to combined liquid components. In this regard, mixing speeds can be adjusted to account for the amount of the material mixed and size of vessel used to prepare the cathode paste. Such adjustments are well known to the skilled artisan. In order to enhance the coatability of the cathode paste onto the current collector, it may be desirable to heat the paste to a temperature of from about 60°C to about 130°C and more preferably, from about 80°C to about 90°C and for a period of time of from about 0.1 to about 2 hours, more preferably, from about 0.1 to 1 hour and even more preferably from about 0.2 to 1 hour. A particularly preferred combination is to heat the paste at from about 80 °C to about 90°C for about 0.33 to about 0.5 hours.

During this heating step, there is no need to stir or mix the paste although such stirring or mixing may be conducted during this step. However, the only requirement is that the composition be heated during this period. In this regard, the composition to be heated has a volume to surface area ratio such that the entire mass is heated during the heating step.

A further description of this heating step is set forth in U.S. Patent Application Serial No. 07/968,203 filed October 29, 1992 as Attorney Docket No. 1116 and entitled "METHODS FOR ENHANCING THE COATABILITY OF CARBON PASTES TO SUBSTRATES", which application is incorporated herein by reference in its entirety.

The so-prepared cathode paste is then placed onto the adhesion layer of the current collector described above by extrusion at a temperature of from about 45° to about 48 °C A Mylar cover sheet is then placed over the paste and the paste is spread to thickness of about 80-90 microns (μm) with a conventional plate and roller system and is cured by continuously passing the sheet through an electron beam apparatus (Electro-curtain, Energy Science Inc. , Woburn, MA) at a voltage of about 175 Kv and a current of about 1.0 Ma and at a rate of about 1 cm/sec. After curing, the Mylar sheet is removed to provide for a solid cathode laminated to the aluminum current collector described above.

C. Electrolyte 56.51 grams of propylene carbonate, 14.13 grams of triglyme, and

17.56 grams of urethane acrylate (Photomer 6140, available from Henkel Corp., Coating and Chemical Division, Ambler, PA) are combined at room temperature until homogeneous. The resulting solution is passed through a column of 4A sodiated molecular sieves to remove water and then mixed at room temperature until homogeneous.

At this point, 2.57 grams of polyethylene oxide film forming agent having a number average molecular weight of about 600,000 (available as Polyox WSR-205 from Union Carbide Chemicals and Plastics, Danbury, CT) is added to the solution and then dispersed while stirring with a magnetic stirrer over a period of about 120 minutes. After dispersion, the solution is heated to between 60 °C and 65 °C with stirring until the film forming agent dissolved. The solution is cooled to a temperature of between 45° and 48°C, a thermo¬ couple is placed at the edge of the vortex created by the magnetic stirrer to monitor solution temperature, and then 9.24 grams of LiPF₆ is added to the solution over a 120 minute period while thoroughly mixing to ensure a sub¬ stantially uniform temperature profile throughout the solution. Cooling is applied as necessary to maintain the temperature of the solution between 45° and 48°C In one embodiment, the polyethylene oxide film forming agent is added to the solution via a mini-sieve such as a 25 mesh mini-sieve commercially available as Order No. 57333-965 from VWR Scientific, San Francisco, CA.

The resulting solution contains the following:

Component Amount Weight Percent^*1

Propylene Carbonate 56.51 g 56.51 Triglyme 14.13 g 14.13 Urethane Acrylate 17.56 g 17.56 iPF₆ 9.24 g 9.24 PEO Film Forming Agent 2.57 g 2.57

Total 100 g 100

* = weight percent based on the total weight of the electrolyte solution (100 g)

This solution is then degassed to provide for an electrolyte solution wherein little, if any, of the LiPF₆ salt decomposes. Optionally, solutions produced as above and which contains the prepolymer, the polyalkylene oxide film forming agent, the electrolyte solvent and the LiPF₆ salt are filtered to remove any solid particles or gels remaining in the solution. One suitable filter device is a sintered stainless steel screen having a pore size between 1 and 50 μm at 100% efficiency. Alternatively, the electrolyte solution can be prepared in the following manner. Specifically, in this example, the mixing procedure is conducted using the following weight percent of components:

Propylene Carbonate 52.472 weight percent

Triglyme 13.099 weight percent Urethane Acrylateb 20.379 weight percent

LiPF₆ 10.720 weight percent

PEO Film Forming Agent^c 3.340 weight percent

(Photomer 6140, available from Harcross Corp., Coating and Chemical Division, Manchester, U.K.) ^€ polyethylene oxide film forming agent having a number average molecular weight of about 600,000 (available as Polyox WSR-205 from Union Carbide Chemicals and Plastics, Danbury, CT)

The mixing procedure employs the following steps:

1. Check the moisture level of the urethane acrylate. If the moisture level is less than 100 ppm water, proceed to step 2. If not, then first dissolve the urethane acrylate at room temperature, < 30°C, in the propylene carbonate and triglyme and dry the solution over sodiated 4A molecular sieves (Grade 514, 8-12 Mesh from Schoofs Inc., Moraga, CA) and then proceed to step 4.

2. Dry the propylene carbonate and triglyme over sodiated 4A molecular sieves (Grade 514, 8-12 Mesh from Schoofs Inc., Moraga, CA).

3. At room temperature, <30°C, add the urethane acrylate to the solvent prepared in step 2. Stir at 300 rpm until the resin is completely dissolved. The solution should be clear and colorless.

4. Dry and then sift the polyethylene oxide film forming agent through a 25 mesh mini-sieve commercially available as Order No. 57333-965 from VWR Scientific, San Francisco, CA. While stirring at 300 rpm, add the dried and pre-sifted polyethylene oxide film forming agent slowing to the solution. The polyethylene oxide film forming agent should be sifted into the center of the vortex formed by the stirring means over a 30 minute period. Addition of the polyethylene oxide film forming agent should be dispersive and, during addition, the temperature should be maintained at room temperature (< 30°C). 5. After final addition of the polyethylene oxide film forming agent, stir an additional 30 minutes to ensure that the film forming agent is substantially dispersed.

6. Heat the mixture to 68 °C to 75 °C and stir until the film forming agent has melted and the solution has become transparent to light yellow in color. Optionally, in this step, the mixture is heated to 65 °C to 68°C

7. Cool the solution produced in step 6 and when the temperature of the solution reaches 40 °C, add the LiPF₆ salt very slowly making sure that the maximum temperature does not exceed 55 °C

8. After the final addition of the LiPF₆ salt, stir for an additional 30 minutes, degas, and let sit overnight and cool.

9. Filter the solution through a sintered stainless steel screen having a pore size between 1 and 50 μm at 100% efficiency.

At all times, the temperature of the solution should be monitored with a thermocouple which should be placed in the vortex formed by the mixer.

Afterwards, the electrolyte mixture is then coated by a conventional knife blade to a thickness of about 50 μm onto the surface of the cathode sheet prepared as above (on the side opposite that of the current collector) but without the Mylar covering. The electrolyte is then cured by continuously passing the sheet through an electron beam apparatus (Electrocurtain, Energy Science Inc. , Wobum, MA) at a voltage of about 175 kV and a current of about 1.0 mA and at a conveyor speed setting of 50 which provides for a conveyor speed of about 1 cm/sec. After curing, a composite is recovered which contained a solid electrolyte laminated to a solid cathode. D. Anode

The anode comprises a sheet of lithium foil (about 51-76 μm thick) which is commercially available from FMC Corporation Lithium Division, Bessemer City, North Carolina.

E. The Solid Electrolytic Cell

A sheet comprising a solid battery is prepared by laminating the lithium foil anode to the surface of the electrolyte in the sheet produced in step C above. Lamination is accomplished by minimal pressure.

While the invention has been described in terms of various preferred embodiments, the skilled artisan will appreciate that various modifications, substitutions, omissions and changes, may be made without departing from the spirit thereof. The descriptions of subject matter in this disclosure are illustrative of the invention and are not intended to be construed as limitations upon the scope of the invention.

Claims

What is Claimed is:

1. A compound of the Formula I: I. A-[Z_a X R²],,,

wherein Z_n is - ( CH2 CHRl O)_n - or - (R50C( 0 )R⁶ C(0)0)_n - wherein R¹ is selected from the group consisting of hydrogen and an alkyl group of 1 to 3 carbon atoms; A is selected from the group consisting of a hydrocarbyl group of from 1 to about 30 carbon atoms, a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms, and a glycidyl residue; n is an integer from about 2 to about 50; R² is selected from the group consisting of hydrocarbyl group of from 1 to 30 carbon atoms, and a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms; X is selected from the group consisting of

(a ) o (b) O

II ii C-O— ; P-O—

0 R4

^(c) ?, ⁽d⁾ ?|

R4 O

and

R3

I

Si-0 — >

I R4

and mixtures thereof . where R³ and R⁴ are hydrocarbyl or oxyhydrocarbyl groups of from 1 to about 7 carbons atoms; R⁵ is a hydrocarbylene or oxyhydrocarylene group of from 1 to 12 carbon atoms; R⁶ is a hydrocarbylene group of from 1 to 12 carbon atoms; and m is an integer of from 1 to about 50.

2. A compound according to Claim 1 wherein R¹ is hydrogen.

3. A compound according to Claim 1 wherein n is an integer between 2 and about 20.

4. A compound according to Claim 1 wherein n is an integer of about 10.

5. A compound according to Claim 1 wherein A is an acryloyl moiety.

6. A solid polymeric electrolyte comprising a solid polymeric matrix obtained by polymerizing a polymer precursor represented by Formula I:

I. A-[Z„ X R²],.,

wherein Z-, is - (CH2 CHRi O)_n - or - (R* 0C(0)R⁶ C(0)0)« - wherein R¹ is selected from the group consisting of hydrogen and an alkyl group of 1 to 3 carbon atoms; A is selected from the group consisting of a hydrocarbyl group of from 1 to about 30 carbon atoms, a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms, and a glycidyl residue; n is an integer from about 2 to about 50; R² is selected from the group consisting hydrocarbyl group of from 1 to 30 carbon atoms, and a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms; OXO is selected from the group consisting of

and

R3

I Si-O—

I

R4

where R³ and R⁴ are hydrocarbyl or oxyhydrocarbyl groups of from 1 to about 7 carbons atoms; R⁵ is a hydrocarbylene or oxyhydrocarbylene group of from 1 to 12 carbon atoms; R⁶ is a hydrocarbylene group of from 1 to 12 carbon atoms; and m is an integer of from 1 to about 50.

7. A solid polymeric electrolyte according to Claim 6 wherein R¹ is hydrogen.

8. A solid polymeric electrolyte according to Claim 6 wherein n is an integer between 2 and about 20.

9. A solid polymeric electrolyte according to Claim 6 wherein n is an integer of about 10.

10. A solid polymeric electrolyte according to Claim 6 wherein A is an acryloyl moiety.

11. A compound according to Claim 1 wherein said solid compound is of number average molecular weight between about 1,000 and 100,000.

12. A solid polymeric electrolyte according to Claim 6 comprising an inorganic ion salt and a compatible electrolyte solvent.

13. A solid polymeric electrolyte according to Claim 6 wherein said solid polymeric matrix is obtained by curing said polymer precursor with actinic radiation.

14. An electrochemical cell which comprises an anode comprising a compatible anodic material; a cathode comprising a compatible cathodic material; and an interposed therebetween a single-phase, solid, solvent- containing solid polymeric electrolytes obtained by polymerizing a polymer precursor represented by Formula I: I. A-[Z-, X R²]_m

wherein Z-, is - ( CH2 CHRⁱ O)_n - or - ( R» OC(0)R6 C(0)0)_n - wherein R¹ is selected from the group consisting of hydrogen and an alkyl group of 1 to 3 carbon atoms; A is selected from the group consisting of a hydrocarbyl group of from 1 to about 30 carbon atoms, a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms, and a glycidyl residue; n is an integer from about 2 to about 50; R² is selected from the group consisting hydrocarbyl group of from 1 to 30 carbon atoms, and a compatible ethylenically unsaturated moiety of from 2 to about 10 carbon atoms; X is selected from the group consisting of

(c) ° (d) ?|

R4 0

and

R3

I Si-O—

I R4

15. An electrochemical cell according to Claim 14 wherein the anode is an interaction anode comprising carbon.

16. An electrochemical cell according to Claim 15 wherein the cathode comprises lithiated cobalt oxides.

17. A battery comprising at least two electrochemical cells of either Claim 14, 15 or 16.