GB2134125A

GB2134125A - Electronically conducting polypyrrole and copolymers of pyrrole, compositions containing them, methods for making them, and electrochemical cells using them

Info

Publication number: GB2134125A
Application number: GB08400463A
Authority: GB
Inventors: Harold M Gerdes; Mark L Daroux; Ned A Godshall
Original assignee: Lubrizol Enterprises Inc
Current assignee: Lubrizol Enterprises Inc
Priority date: 1983-01-24
Filing date: 1984-01-09
Publication date: 1984-08-08
Also published as: DK29184D0; KR840007487A; NO840236L; GB2184738A; DE3402133A1; JPS59166529A; DK29184A; IT8447573A0; GB8701664D0; IL70617A0; GB2134125B; FI840229A0; BE898733A; FI840229A; IN160942B; GB8400463D0; BR8400230A; SE8400331D0; FR2539916B1; ES8602887A1

Abstract

Electronically conducting compositions comprising electropolymerised polypyrrole or copolymers of a pyrrole are described. These compositions may be either porous or non-porous materials in the form of films, powders, dendriform materials, or various shapes formed as desired by pressing powders of the compositions of the invention. The electronically conducting compositions of the invention can be prepared by several processes which are described, and a preferred process involves a multi-phase system, and more preferably, a two-phase system, one phase being aqueous. These compositions are stable over a range of chemical and electrochemical conditions and are useful in a number of applications, including electrodes for electrochemical cells such as electrochemical energy storage cells.

Description

SPECIFICATION Electronically conducting polypyrrole and copolymers of pyrrole, compositions containing them, methods for making them, and electrochemical cells using them Technical field This invention relates to polypyrrole and co polymers of pyrrole. More particularly, this invention relates to electronically conducting compositions comprising electropolymerized polypyrrole or a co-polymer of pyrrole; to methods for making electronically conducting polypyrrole or co-polymers of pyrrole; and to electrochemical cells comprising polymeric electrode means, said polymeric electrode means being positive and/or negative and comprising electronically conductive polypyrrole or a copolymer of pyrrole.

Background of the invention The term polypyrrole means polymers containing polymerized pyrrole rings. A pyrrole ring is an unsaturated five membered ring containing four carbon atoms and one nitrogen atom. Polypyrrole is not limited herein to polymers of unsubstituted pyrrole monomer, nor is it limited to polymerization at specific sites in the pyrrole rings. A preferred polypyrrole for use in accordance with the present invention is the 2,5 polymerized homopoiymer of unsubstituted pyrrole. The term co-polymer of pyrrole means any polymer containing pyrrole and/or substituted pyrrole monomers and/or one,or more other monomers coplymerizable therewith.

Polypyrrole belongs to the general class of electronically conducting organic polymers, and more specifically is one of the group of polymers -which may, under certain conditions, have conductivities exceeding about 1 ohm-lcm-l that have been developed in recent years. Other well known members of this group are polyacetylene, poly-p-phenylene, poly-p-phenylene sulfide and poly (2,5 thienylene).

Pyrrole black, a polymeric powdered material formed by oxidizing pyrrole in homogeneous solution (e.g. with H2O2) has been known for many years. Gardini,Adv. Heterocycl. Chem, 15, 67 (1973). An electrochemical method of producing polypyrrole as a powdery film on an electrode has been reported. A. Dall' Olio et al., Comp. Rend., 433, 267c (1968).

Electropolymerization to produce polymer films from pyrrole has been reported. Diaz et al J.

Chem. Soc, Chem. Comm., 635, (1979) (hereinafter Diaz (I)); Diaz et al, J. Chem. Soc, Chem. Comm, 397, (1980) (hereinafter Diaz (all)); Diaz, Chemica Scripta, 17, 45, (1981) (hereinafter Diaz (III)); and Kanazawa et al., J. Chem. Soc., Chem. Comm., 954 (1979) (hereinafter Kanazawa (I)). Electropolymerized polypyrrole from substituted pyrroles has been reported. Diaz (all); Diaz et al., J. Electroanal Chem., 129, 115, (1981) (hereinafter Diaz (IV)); Diaz et al., J.

Electroanal Chem., 130, 181, (1 981) (hereinafter Diaz (V)). Co-polymer films produced by electropolymerizing mixtures of pyrrole and substituted pyrrole have also been reported. A mixture of pyrrole and N-methyl-pyrrnle has been polymerized and it is believed that both monomers are incorporated into the polymer. Diaz (all); Diaz, Proc. Int. Conf. on Low Dimensional Synthetic Metals Chemica Scripta, 17, 0000, (1981), (hereinafter Diaz (VI)); and Kanazawa et al. J. Synth Metals, 4, 1 19, (1981) (hereinafter Kanazawa (II)).

Polypyrrole is electronically conducting in the charged or oxidized state (black), and is produced in this state by electropolymerization. When it is completely reduced to the neutral or discharged state (yellow), it is an electronic insulator. The electropolymerized polypyrrole is produced in the oxidized, i.e. conductive, state and (unlike other conducting polymers such as polyacetylene) does not require any subsequent chemical or electrochemical treatment to increase its conductivity above 1 ohm-'cm-'. A counteranion is incorporated into the material during the electropolymerization process to balance the positive charge on the polymer backbone. Diaz (Ill).

Polypyrrole can be made as powders Gardini, supra. Polypyrrole can also be electropolymerized as a continuous film on electrodes. The highest electronic conductivities reported for the continuous films are of the order of about 100 ohm-1cm#1. Diaz (I); Kanazawa et al., Syn. Metals, 1, 329, (1980) (hereinafter Kanazawa (III). These conductivities can be orders of magnitude lower depending on the counter-anion incorporated.

A large number of counter-anions have been used, including BF4-, PFJ, AsFJ, Cl04-, HSO4-, CF3SO3-, C H3C6H4SO3-, CF3COO-, HC2O4-, Fe(CN)63 Diaz (IV); Diaz (VI); Kanazawa (I); and Noufi et al,J. Electrochem. Soc., 128, 2596, (1981).

N-substituted pyrroles have been polymerized, including methyl, ethyl, n-propyl, n-butyl, isobutyl and phenyl and substituted phenyl pyrroles. Diaz (IV) Diaz et al., Electrochemical Society Extended Abstracts, Vol. 82-1. Abstract No. 617, (1982) (hereinafter Diaz (VII)). These materials have reported electronic conductivities orders of magnitude lower than polypyrrole itself.

Kanazawa (all); Diaz (VII). It has been reported that beta-substituted pyrroles such as 3,4 dimethyl pyrrole have been polymerized. Gardinia, supra.

The polymers have been prepared to date with non-aqueous solvents, typically acetonitrile, (Diaz (I); Diaz (all); and Diaz (Vl)), containing a dissolved salt which provides the counter-anion. It is known that the physical properties of the resulting films are sensitive to the formation conditions. For example, in acetonitrile, small traces of water in the solvent produce a film with a smoother surface than that produced in anhydrous acetonitrile. Diaz (VI). The polypyrrole tetrafluoroborate films produced by Diaz et al. are continuous, space-filling and very poorly crystalline with a density of 1.48 g cm~3.

Kanazawa (III).

Polypyrrole films are thermally stable at room temperature and are insoluble in common solvents. Diaz (I); Kanazawa (all); and Tourilion et al., Electrochemical Society Extended Abstracts, Vol. Abstract 618, (1982). Polypyrrole in the oxidized form is reported to be chemically stable in ambient conditions of O2 and moisture for several months. Diaz et al., J. Electroanal, Chem., 121 355, (1981) (hereinafter Diaz (VIII)); Watanabe et al Bull. Chem. Soc. Jpn., 54, 2278, (1981). Polypyrrole fluoroborate films have been shown to be unstable under oxidative conditions such as potentials greater than +0.6 V. (SCE) or in the presence of halogens. Bull et al, J.

Electrochem. Soc., 129, 1009 (1982).

Polypyrrole can be driven repeatedly between the conducting and non-conducting state. Bull et al, supra; Diaz et al, "Conducting Polymers", Polymer Sci. 8 Technology, p. 149 et. seq., Plenum Press, N.Y., (1981) (hereinafter Diaz (IX)).

Rapid complete switching is reported-to require the use of thin films (i.e., less than about 0.1 micrometer) and switching is difficult for thicknesses greater than about 1 micrometer.

Diaz (all); Diaz (IX). It has been shown that although a film may contain BF4- counter-anions when it is formed (i.e., is the charged state) BF4is no longer present in the film when it is in the neutral (i.e., reduced or discharged) state. Diaz (IV). It has been suggested that both the anion and the cation of the electrolyte salt affect ion diffusion during reduction and oxidation of polypyrrole films. (Diaz (IV).

Polymers have been produced with different degrees of oxidation, depending on the anion and/or substituents. Most of these materials have degrees of oxidation around 0.25 (i.e., one quarter of the polymer rings are oxidized).

Summary of the invention The compositions of the present invention are electronically conducting compositions which comprise an electropolymerized polypyrrole or copolymer of pyrrole, and these compositions may be either porous or non-porous materials in the form of films, powders, dendriform materials, or various shapes formed as desired by pressing powders of the compositions of the invention.

These compositions are particularly suitable in the formation of positive and/or negative polymeric electrodes for use in electrochemical cells such as, for example, electrochemical energy storage cells.

The present invention contemplates the provision of a porous electronically conducting compositions comprising an electropolymerized polypyrrole or co-polymer of pyrrole, said composition characterized by an apparent density of from about 0.01 g cm~3 up the bulk density of said polypyrrole or co-polymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.

The invention further provides for an electrochemical cell comprising polymeric electrode means, said polymeric electrode means being positive and/or negative and comprising the foregoing composition.

Further, the present invention provides for an electronically conducting composition comprising electropolymerized polypyrrole or a co-polymer of pyrrole, said composition containing one or more low mobility anions characterized by an average ionic transference number for said low mobility anions during reduction of less than about 0.1.

Further, the present invention contemplates the provision of a method of preparing electronically conducting polypyrrole or copolymers of a pyrrole which comprises electropolymerization of pyrrole or a copolymerizable mixture containing pyrrole at an electronically conductive surface in an electrolytic bath, the method comprising the steps: (A) immersing an electronically conductive surface in an electrolytic bath comprising at least one liquid and at least one non-miscible liquid or gas or finely divided solid particles wherein the pyrrole or the copolymerizable mixture containing a pyrrole is one of the liquids or is dissolved in at least one of the liquids, and (B) passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or copolymerizable mixture containing a pyrrole at the electronically conductive surface.In a preferred embodiment of this method the electrolytic bath comprises an aqueous mixture comprising pyrrole, or mixture of pyrrole and a copolymerizable monomer and water. The invention further provides for an electrochemical cell comprising polymeric electrode means, said polymeric electrode means being positive and/or negative and comprising electronically conducting polypyrrole or a copolymer of pyrrole prepared in accordance with the foregoing method.

Further, the present invention provides for a method of preparing electronically conducting polypyrrole or a co-polymer of pyrrole which comprises the steps of: (A) electropolymerizing a pyrrole or a copolymerizable mixture of a pyrrole at an electronically conductive surface in an electrolytic bath by (1) immersing an electronically conductive surface in an electrolytic bath which comprises (a) an aqueous dispersion of a pyrrole, or a mixture of said aqueous dispersion and at least one copolymerizable monomer or (b) a pyrrole or a mixture of a pyrrole and/or at least one copolymerizable monomer, water and a water-immiscible diluent, (2) agitating the bath, and (3) passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or pyrrole mixture and deposit the polymer or co-polymer on the electronically conductive surface, and (B) removing said polymer or co-polymer from the conductive surface. In a preferred embodiment of this method, the electrolytic bath comprises an aqueous mixture comprising pyrrole or a copolymerizable mixture of pyrrole, water, and one or more low mobility anions which are incorporated into the polypyrrole by electropolymerization and which anions are characterized by an average ionic transference number for said low mobility anions on reduction of less than about 0.1. The invention further provides for an electrochemical cell comprising polymeric electrode means, said polymeric electrode means being positive and/or negative and comprising polypyrrole or a co-polymer of pyrrole prepared in accordance with the foregoing method.

Further, the present invention provides for a method of preparing electronically conducting polypyrrole or a co-polymer of pyrrole which comprises electropolymerization of a pyrrole or a copolymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath by (A) immersing an electronically conductive surface in an electrolytic bath comprising (i) a pyrrole or a mixture of a pyrrole with a copolymerizable monomer, (ii) one or more low mobility anions which are incorporated into the polypyrrole or co-polymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of the polypyrrole or copolymer of less than about 0.1, and (iii) an organic diluent, and (B) passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or copolymerizable mixture containing pyrrole at the electronically conductive surface. The invention further provides for an electrochemical cell comprising polymeric electrode means, said polymeric electrode means being positive and/or negative and comprising polypyrrole or a co-polymer of pyrrole prepared in accordance with the foregoing method.

Brief description of the drawings Fig. 1 is a sectional side elevational view of a laboratory scale lithium cell illustrating the present invention in a particular form; Fig. 2 is a side elevational view of a laboratory scale electrochemical cell illustrating an alternate embodiment of the present invention in a particular form; Fig. 3 is a perspective view of an electrochemical energy storage cell illustrating another alternate embodiment of the present invention in a particular form; Fig. 4 is a sectional side elevational view of the electrochemical cell illustrated in Fig. 3; Fig. 5 is a sectional side elevational view of an electrochemical energy storage cell illustrating another alternate embodiment of the present invention in a particular form;; Fig. 6 is a sectional side elevational view of a layered or stacked electrochemical energy storage cell illustrating another alternate embodiment of the present invention in a particular form; and Fig. 7 is a sectional side elevational view of a layered or stacked electrochemical energy storage cell illustrating still another alternate embodiment of the present invention in a particular form.

Description of the preferred embodiments In a preferred embodiment of this invention, the electronically conducting compositions of the invention contain at least one low mobility anion, A, which has a strong tendency to be retained in the composition on reduction. The transport of ionic charge to compensate the change in oxidation state of the polymer is then carried out principally by ions of the electrolyte in which the redox process is carried out. The low mobility anions may be characterized by their ionic transference numbers. The ionic transference number is defined as the fraction of the ionic current carried by the particular anion averaged over substantially full reduction of the composition. The polymer is formed in the oxidized state (black) which is electronically conductive and can be reduced to the neutral state (yellow) which is insulating.However, for practical purposes, the reduction of thick (500 millimicron or greater) films does not proceed to completion even at very negative potentials. The material remains black in appearance and retains some electronic conductivity although above about 90% reduction its resistance may increase.

In general, the low mobility anions utilized in the compositions of this invention will be characterized by an average ionic transference number for said low mobility anions during reduction of less than 0.1 and preferably less than about 0.05. A most preferred low mobility anion is one characterized by an average ionic transference number for said low mobility anions during reduction of less than 0.01.

These transference numbers may be determined by elemental analysis of the polymers before and after reduction. Thus, the transference number (tA) of the low mobility anion may be defined as follows: tA=AN,/(N#)0 wherein (NA)o is the number of moles of the charge compensating anion initially in the polymer (when it is in the oxidized state) and A NA is the change in the number of moles of the anion after subtantially full reduction (towards the neutral state).

The porous compositions of the invention also are characterized by an apparent density of from about 0.01 g cm up to about the bulk density of the polypyrrole or co-polymer of pyrrole.

Bulk or theoretical density of the polymers is the density of continuous, pure polymer containing no voids, pores, cavities or inclusions.

The bulk or theoretical density can usually be determined by flotation methods. Apparent density for less dense forms of the polymer such as the porous materials is defined from the mass of the polymer and the volume calculated from the external dimensions of the material. Since voids, cavities, etc., are included in the porous type materials, their apparent density will be lower than the bulk density.

The porous composition of the invention also is characterized as having an electrochemically accessible surface area of at least two times the surface area of a smooth film of bulk density of the polymer or co-polymer. Preferred materials have significantly greater surface areas, (e.g., 1000 times or more than that of a smooth film of bulk density).

The electronically conducting compositions of the present invention comprise either polypyrrole(s) or co-polymer(s) of pyrrole which may be obtained by (a) polymerizing mixtures of a pyrrole with other co-polymerizable monomers or by (b) grafting a co-monomer(s) to a polypyrrole polymer or by (c) grafting a pyrrole monomer(s) to a preformed polymer based on a monomer other than pyrrole.

The pyrrole monomers which can be electropolymerized may be pyrrole or substituted pyrroles such as the N-substituted or Csubstituted pyrroles as described more fully below. Homopolymers of these pyrroles, and preferably the homopolymers of unsubstituted pyrrole are included.

Co-polymers of a pyrrole can be prepared, for example, by polymerizing a mixture of pyrrole and one or more substituted pyrroles which may be substituted either on the nitrogen atom or at one or more of the ring carbon atoms in the beta pbsition. Preferably, the substituent is a lower alkyl group containing from 1 to 7 carbon atoms, and it is more preferably a methyl group. Thus, for example, co-polymers of pyrrole and Nmethylpyrrole or 3,4-dimethyl pyrrole can be prepared in accordance with the methods of the invention. Alternatively, pyrrole can be copolymerized with other heterocyclic ring compounds including those containing nitrogen (e.g., pyridine, aniline, indole, etc.), furan and thiophene or with other aromatic or substituted aromatic compounds.

The low mobility anions which are incorporated into the compositions of the invention may be either organic or inorganic anions. Examples of low mobility inorganic anions useful in the present invention include transition metal complexes such as ferricyanide, nitroprusside, iron/sulfur cluster compounds such as the redox centers of the rubredoxins and the ferredoxins, boron cluster compounds, cobalt hexacyanide, other transition metal cyanide complexes, nitroprusside complexes, and other transition metal oxy complexes or sulfides or chalcogenide complexes, e.g. WO4-, MoO4-, Mo(CN)84#, Fe4S4C4H12#, Cur0,6, etc.

Preferably, the low mobility anions included in the compositions of the present invention are organic anions. Examples of organic anions include those derived from organic sulfates or sulfonates, and these may be alky, cycloalkyl, aryl, arylalkyl or alkaryl sulfates and sulfonates. The anions which are useful in the present invention may contain more than one anionic site, i.e., more than one ionizable group per molecule, e.g. more than one sulfonic acid group per molecule.The sulfonates and sulfates useful as the low mobility anions in the compositions of the present invention may be represented by the following formulas: R'(SO3)x- Formula I R2(SO3)X- Formula II R'(OSO3)x- Formula Ill R2(OSO3)xX# Formula IV R2yT(so3)xx- Formula V RlyT(503)x7 Formula Vl In the above formulas, R' is an aliphatic or an aliphatic substituted cycloaliphatic hydrocarbon or an essentially hydrocarbon group generally free from unsaturation and usually containing up to about 30 carbon atoms although it may be polymeric and contain more than 30 carbon atoms.When R' is aliphatic, it usually contains at least about 4 carbon atoms, and when Ra is alkyl substituted cycloaliphatic, the alkyl substituents preferentially contain from 1 to 4 carbon atoms.

Specific examples of R1 include butyl, hexyl, octyl, lauryl, cetyl, octadecyl and groups derived from petroleum, saturated and unsaturated paraffin wax, and olefin polymers including polymerized mono-olefins and diolefins containing from 2 to about 8 carbon atoms per olefinic monomer unit.

R' can also contain other substituents such as phenyl, cycloalkyl, hydroxy, mercapto, halo, nitro, amino, lower alkoxy, lower alkylmercapto, carbalkoxy, oxo or thio, or interrupting groups such as -NH-, -0-, -S-, but preferably its overall hydrocarbon character is retained.

R2 generally is a hydrocarbon or essentially hydrocarbon group containing from 1 to about 30 carbon atoms, although it may be polymeric and contain more than 30 carbon atoms. R2 is preferably an aliphatic hydrocarbon group such as alkyl, alkenyl, or alkylaryl. R2 also may contain substituents such as those enumerated above, including the above indicated interrupting groups, provided the essentially hydrocarbon character thereof is retained.

The group Tin the above formulas V and Vl is a cyclic nucleus which may be derived from an aromatic hydrocarbon such as benzene or from a heterocyclic compound such as pyridine.

Ordinarily, T is an aromatic hydrocarbon nucleus and especially benzene. The subscript and superscript x represents the average number of ionized groups per molecule. The anion may contain additional sulfate or sulfonate groups which are not ionized but associated with some cationic species. In Formulas I through Vl, x may have a value of up to 1000 or more when R' or R2 is polymeric, but is preferably from 1 to 10, more preferably from 1 to 6, and generally is 1. The subscript y in Formulas V and Vl is a number ranging from 1 to 5 and preferably is 1.

Anionic compounds containing the anions represented above by Formulas I through Vl are available commercially or can be prepared readily by techniques known in the art. Examples are salts with alkali or alkaline earth metals, or ammonium salts.

Examples of sulfonates useful in the invention include the anions of the following acids; hexyl sulfonic acid, octyl sulfonic acid, dodecyl sulfonic acid, octyldecyl sulfonic acid, lauryl sulfonic acid, mahogany sulfonic acid, paraffin wax sulfonic acid, benzene sulfonic acid, naphthalene sulfonic acid, lauryl cyclohexyl sulfonic acid, dodecyl benzene sulfonic acid; polyethylene sulfonic acids of various molecular weights; polystyrene sulfonic acids of various molecular weights, etc.Styrene maleic anhydride co-polymers bearing sulfonate groups on the rings or styrene maleic anhydride co-polymers which have been partially or fully converted to the corresponding imide sulfonates are also useful anionic species in the invention; such materials are derived from styrene maleic anhydride co-polymers typically having inherent viscosity of about 0.06 to about 1, preferably about 0.06 to about 0.3 dl g-l measured at 300C in acetone,0.4~1 g dl-1.

A preferred embodiment includes anions derived from aliphatic compounds containing two sulfonic acid groups and may be represented by the formula (CH2)n(SO3)2 Formula Vli wherein n is an integer from about 2 to 20 or more and preferably about 2 to 12. These disulfonic acid salts can be prepared by techniques known in the art such as by the reaction of alkylene dihalides with sodium sulfite.

Specific examples of such compounds include the salts of ethane disulfonic acid, 1 ,4-butane disulfonic acid, 1 5-pentane disulfonic acid, 1,6hexane disulfonic acid, 1,8-octane disulfonic acid and 1,1 0-decane disulfonic acid.

Examples of sulfates which are useful include alkyl sulfates such as lauryl sulfate; and polyethylene sulfates of various molecular weights.

Another class of sulfates which are useful as the low mobility anions in the compositions of the present invention are polysulfated polyhydroxy compounds. Such compounds can be obtained by reacting polyhydroxy compounds with an appropriate reagent such as chlorosulfonic acid thereby converting one or more of the hydroxy groups to sulfate groups. Examples of polyhydroxy compounds which can be used to prepare such polysulfates include pentaerythritol, mannitol, trimethylolpropane, dipentaerythritol, etc. As mentioned, one or more of the hydroxy groups in these polyhydroxy compounds can be sulfated to produce a variety of products. Ammonium sulfates can be prepared directly from polyhydroxy compounds by reaction with an aminosulfonic acid in the presence of a diluent such as dimethyl formamide.

Amido, and preferably acrylamide alkane sulfonic acid anions can be used in the compositions of the invention. Specific examples of such anions include: 2,2-bisacrylamido- 1,1 - dimethylethanesulfonic acid anion; 2-acrylamido2-methyl propane sulfonic acid anion; and poly(2acrylamido-2-methyl propane sulfonic acid sodium salt of various molecular weights.

The low mobility anions included in the compositions of the present invention may also be derived from pentavalent phosphorous compounds. Examples of such phosphorous compounds are phosphates, phosphonates and phosphinates. The phosphorous compounds useful as the low mobility anions in the compositions of the present invention may be represented by the following formulas:

For example, many of the higher molecular weight sulfates or sulfonates listed above as low mobility anions, also function as plasticizers and, additionally, can modify the wetting properties of the polymer. A specific example is sodium lauryl sulfate which functions as a low mobility anion and as a plasticizer for polypyrrole and copolymers of pyrrole.

The plasticizers which are useful in the present invention include organic sulfates or sulfonates such as alkyl, aryl, arylalkyl, alkaryl and polyolefin sulfates or sulfonates of the types listed above as low mobility anions. Another class of compounds useful as plasticizers and the compositions of the present invention are polyhydroxy compounds.

The polyhydroxy compounds are preferably those containing from 2 to 6 alcoholic radicals of which at least 1 is unsubstituted. The unsubstituted polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3- propylene glycol, glycerol, erythritol, pentaerythritol, arabitol, adonitol, xylitol, mannitol, sorbitol, and neopentylglycol. Higher molecular weight polyhydric alcohols are also useful. Examples of such alcohols include various polyethylene glycols, and polypropylene glycol.

Partially acylated polyhydric alcohols likewise are contemplated for use herein. The partially acylated polyhydric alcohols are preferably those containing from 2 to 6 alcoholic radicals of which at least one but not all are acylated with an aliphatic carboxylic acid having from about 8 to about 30 carbon atoms. Examples are glycerol mono-oleate, glycerol di-stearate, sorbitan monostearate, sorbitan di-decanoate, sorbitan tristearate, sorbitan di-behenate, erythritol mono oleate, 1,1,1-trimethylol propane monomyristate, pentaerythritol di-linoleate, ribitol mono-(9,10-dichloro stearate), sorbitan monooleate, etc.

The polyhydric alcohols may also contain ether linkages within their molecular structure. The ether-containing polyhydric alcohols may be obtained by dehydrating a polyhydric alcohol.

Examples of such derivatives are sorbitan and mannitan. The ether-containing polyhydric alcohols may also be obtained by reacting a polyhydric alcohol with an epoxide. The epoxides are for the most part hydrocarbon epoxides and substantially hydrocarbon epoxides. The hydrocarbon epoxide may be an alkylene oxide or and aryl-alkylene oxide. The aryl-alkylene oxides are exemplified by styrene oxide, paraethylstyrene oxide and para-chlorostyrene oxide.

The alkylene oxides include principally the lower alkylene oxides such as ethylene oxide, propylene oxide, 1 ,2-butene oxide and 1,2-hexene oxide.

The substantially hydrocarbon epoxides may contain polar substituents. The polar substituent is usually a halo radical such as chloro, fluoro, bromo, or iodo; an ether radical such as methoxy or phenoxy; or an ester radical such as carbomethoxy. Examples of such epoxides are epichlorohydrin and butyl, 9,10-epoxy-stearate.

The number of ether linkages in the product is

In the above formulas R3 is R1 or RlyT as defined above, or can be hydrogen, an alkali metal (.e.g, lithium, sodium, potassium, etc.) or an alkaline-earth metal (e.g., calcium, magnesium, etc.). R4 is R2 or R2yT, as defined above, or can be hydrogen, an alkali metal (e.g., lithium, sodium, potassium, etc.) or an alkaline earth metal (e.g., calcium, magnesium, etc.). Each of X', X2, X3 and X4 is oxygen or sulfur; and each a and b is 0 or 1.

The subscript and superscript z represents the average number of ionized groups per molecule.

In Formulas Xl through XIV, z may be a value of up to 1000 or more when R' or R2 is polymeric, but is preferably from 1 to 10, more preferably from 1 to 4, and generally is 1. Thus, it will be appreciated that the pentavalent phosphorous compounds may be for example, organophosphoric, phosphonic or phosphinic compounds including the acids, alkali metal salts and alkaline-earth metal salts thereof, or a thio analog of any of these.

Although useful electronically conducting compositions can be prepared in accordance with the method of the invention comprising a polypyrrole or a co-polymer of a pyrrole, and a low mobility anion as described above, the properties of the compositions may be improved by the inclusion of other components which provide certain desirable properties. The electrolytic baths useful in the formation of the compositions of this invention preferably will contain a plasticizer.

Plasticizers are compounds known in the art which have the ability when incorporated into polymeric compounds such as polypyrrole or copolymers of a pyrrole to increase stretch elongation and/or decrease the modulus of the polymer and/or increase flexibility. The last criterion has been used to define the term plasticizer as applied to the materials in this application. Compounds which can increase the flexibility of the compositions of the invention generally are included in the electrolytic baths. In some instances, the low mobility anions which are incorporated into the compositions of the invention have more than one function and may, for example, include the function of a plasticizer and/or a surface active agent in the composition.

determined by the amount of epoxide added. Thus it is possible to react polyhydric alcohol such as sorbitol with 1, 2, 3 or more equivalents of an epoxide such as propylene oxide.

The polyhydric alcohols contemplated for use in this invention may also be ether-containing acylated polyhydric alcohols. These may be prepared by a number of methods. A polyhydric alcohol may be dehydrated and subsequently acylated or an alcoholic radical may be acylated first followed by dehydration of other alcoholic radicals. As mentioned previously, the ether linkage may also be introduced by the reaction of an epoxide with the polyhydric alcohol either before or after acylation. Examples of ethercontaining acylated polyhydric alcohols include polyoxyethylene sorbitan mono-oleate, polyoxyethylene sorbitan tri-stearate, polyoxyethylene glycerol di-stearate, polyoxypropylene sorbitan di-linoleate, and polyoxypropylene penta erythritol mono-oleate.

A particularly preferred example of a class of plasticizers useful in the compositions of the invention are polyalkylene polyols, polyethers and polyglycerols, and particularly polyalkylene glycols wherein the monomer unit may contain from 1 to about 4 carbon atoms and preferably about 2 carbon atoms. A specific example is polyethylene glycol. The molecular weight of the plasticizers may vary over a wide range depending upon the composition to be modified and the properties which are to be modified by inclusion of the plasticizer. Polyethylene glycols of molecular weight of from about 300 to about 5,000,000 are included in the electrolytic bath composition and are useful in modifying the properties of the compositions of the present invention.

It also has been discovered that when the electropolymerization of pyrrole or polymerizable mixtures of pyrrole is carried out using either an aqueous medium or a multi-phase system as described below, the presence of polyethylene glycol over a range of molecular weights confers mechanical strength and flexibility to the polymeric compositions obtained. Moreover, when polyethylene glycol of various molecular weights is added to electrolytic baths of the invention, the morphology of the polymeric composition obtained generally can be modified by varying the molecular weight of the glycol added.

The amount of plasticizer included in the electrolytic bath of the invention may vary over a wide range, particularly if the low mobility anion also functions as a plasticizer. Generally, however, the electrolytic bath compositions of the invention will contain less than about 75% of plasticizer and preferably, less than about 25% by weight of the plasticizer based on the total weight of the bath composition.

The compositions useful in the preparation of the compositions of the invention also may contain redox species. Redox species are chemical species that are able to undergo changes in oxidation state and can be oxidized or reduced at an electrode. In this context, the species should generally be reduced before or during the reduction of the polymer beyond that required to change the oxidation state of polymer alone, and, therefore, stores additional charge.

The oxidation and reduction of this species may or may not be reversible. The incorporation of redox species having suitable redox potentials into the compositions of the invention generally results in an increase in the charge capacity of the composition. Charge capacity of a polymer composition is the total charge consumed per unit mass when the material is oxidized or reduced usually expressed in coulombs/g or ampere hours/kg. Examples of redox species which are useful include transition metal complexes and more preferably anionic transition metal complexes.Examples of complexes include halide complexes, amine complexes wherein the amine may have the formula -NR5R6 R7 wherein each R5, R6 and R7 independently may be hydrogen or an alkyl or an aryl group; oxy complexes such as molybdates, tungstates, vanadates; cyanide complexes such as hexacyanide complexes of transition metals, iron cyanides, cobalt cyanides and molybdenum cyanide complexes. Other redox species which are useful include nitroprussides, polysulfides, transition metal oxy compounds, sulfur compounds or chalcogenides.

The redox species may be included in ionic form in the compositions of the invention up to about 70% by weight based on the weight of the total composition. Preferably, redox species are incorporated in anionic form up to the amount necessary to neutralize the charge on the polymer backbone.

Surface active agents, also variously referred to as wetting agents or emulsifying agents, may be included in the compositions of the invention and in the electrolytic baths utilized to form the compositions of the invention. The surface active agent may be hydrophilic or hydrophobic.

Typically, the surfactant is a hydrophilic surfactant, and generally, has an HLB (hydrophilic-lipophilic balance) in the range of about 10 to about 20.

The surfactant can be of the cationic, anionic, non-ionic or amphoteric type. Many such surfactants of each type are known to the art.

See, for example, McCutcheon's "Detergents and Emulsifiers',1978, North American Edition, published by McCutcheon's Division, MC Publishing Corporation, Glen Rock, New Jersey, U.S.A., particularly pages 17-33 which are hereby incorporated by reference for their disclosures in this regard.

Anionic surfactants contain negatively charged polar groups while cationic surfactants contain positively charged polar groups.

Amphoteric surfactants contain both types of polar groups in the same molecule. A general survey of useful surfactants is found in Kirk-Othmer Encyclopedia of Chemical Technology, Second Edition, Volume 19, page 507 and following (1969, John Wiley and Son, New York) and the aforementioned compilation published under the name of McCutcheon's. These references are both hereby incorporated by reference for their disclosures relating to cationic, amphoteric and anionic surfactants. The anionic or non-ionic surfactants are preferred. The low mobility anion incorporated into the polymer may additionally perform the function of a surface active agent.

Among the useful anionic surfactant types are the widely known metal carboxylate soaps, organo sulfates, sulfonates, sulfocarboxylic acids and their salts, and phosphates. Useful cationic surfactants include nitrogen compounds such as amine oxides and the well known quaternary ammonium salts. Amphoteric surfactants include amino acid type materials and similar types.

Various cationic, anionic and amphoteric dispersants are available from the industry particularly from such companies as Rohm and Haas and Union Carbide Corporation. Among the non-ionic surfactants are the alkylene oxidetreated products, such as ethylene oxide-treated phenols, alcohols, esters, amines and amides.

Ethylene oxide/propylene oxide block co-polymers are also useful non-ionic surfactants. Glycerol esters and sugar esters are also known to be nonionic surfactants. A typical non-ionic surfactant class useful with the derivatives of the present invention are the alkylene oxide-treated alkyl phenols such as the ethylene oxide alkyl phenol condensates sold by the Rohm s Haas Company.

A specific example of these is Triton X-100 which contains an average of 9-10 ethylene oxide units per molecule, has an HLB value of about 13.5 and a molecular weight of about 628. Many other suitable non-ionic surfactants are known; see, for example, the aforementioned McCutcheon's as well as the treatise "Non-ionic Surfactants" edited by Martin J. Schick, M.

Drekker Co., New York, 1967, which is hereby incorporated by reference for its disclosures in this regard.

Further information about anionic and cationic surfactants also can be found in the texts "Anionic Surfactants", Parts II and Ill, edited by W. M. Linfield, published by Marcel Dekker, Inc., New york, 1976, and "Cationic Surfactants", edited by E. Jungermann, Marcel Dekker, Inc., New York, 1976. Both of these references are incorporated by reference or their disclosures in this regard.

The electronically conducting polypyrrole or co-polymers of pyrrole of the present invention are prepared by electropolymerization of a pyrrole or a co-polymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath. The electrolytic bath contains a pyrrole or mixture of pyrrole and co-polymerizable monomer, at least one electrolyte salt which includes an anion while will be incorporated into polymer upon formation and at least one liquid in which the pyrrole (and/or co-polymer) and electrolyte salt together have some finite solubility. The bath may additionally contain a second non-miscible liquid or a gas or finely divided solid particles or combinations thereof. In one embodiment, the electrolytic bath comprises a pyrrole or co-polymerizable mixture of pyrrole and water.In another embodiment the electrolytic bath comprises the pyrrole or co-polymerizable mixture of pyrrole and an organic diluent. In yet another embodiment, the electrolytic bath comprises the pyrrole or co-polymerizable mixture containing pyrrole, water, and a non-miscible liquid such as an organic diluent. The last embodiment wherein the bath contains water and a non-miscible organic diluent, hereinafter referred to as the two-phase system, is useful in preparing compositions of the invention which may be characterized as being porous and having very high surface areas.

The electropolymerization of a pyrrole or a copolymerizable mixture containing a pyrrole utilizing a two-phase system such as water and an organic diluent comprises the steps of A. immersing an electronically conductive surface in an electrolytic bath comprising at least one liquid and at least one non-miscible liquid wherein the pyrrole or co-polymerizable mixture is one of the liquids or is dissloved in at least one of the liquid and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing a pyrrole at the electronically conductive surface.

Preferably, one of the liquids is water and the non-miscible liquid is an organic diluent.

Examples of organic diluents useful in the present invention include organic hydrocarbons such as aliphatic or aromatic hydrocarbons, halogenated aliphatic or aromatic compounds, etc. Specific examples include mineral spirits, hexane, heptane, toluene, xylene, 1 ,2-dichloroethane, dichloromethane, carbon tetrachloride, and chlorobenzene.

The amount of the pyrrole or co-polymerizable mixture containing pyrrole in the electrolytic bath may vary over a wide range although the total amount must exceed the amount necessary to form the total amount of polymer desired. The amount of the pyrrole dissolved in the electrolyte solution component(s) of the electrolytic bath must be enough to permit a reasonable rate of reaction. This amount will usually vary from about 10-3 molar up to saturation of the electrolyte(s).

The amount of electrolyte salt in the electrolytic bath must be sufficient to both conduct the current desired and provide sufficient anionic species for incorporation into the polymer for the purpose of charge neutralization. Typical concentrations are from 10-2 molar up to saturation of the bath, and more typically 5x10-2 up to 1 molar in at least one phase.

As mentioned above, the electrolytic bath of the invention may contain other ingredients which provide desirable properties to the compositions of the invention. Thus, the bath may contain low mobility anions, plasticizers, redox couples, surfactants, etc., as defined above. When an aqueous system or a multi-phase system containing water is utilized for the electrolytic bath, an emulsifier or emulsion stabilizer may be included to stabilize this system.

The emulsifier may be an aliphatic glycol or a monoaryl ether of an aliphatic glycol. The aliphatic glycol may be a polyalkylene glycol. It is preferably one in which the alkylene radial is a lower alkylene radical having from 1 to 10 carbon atoms. Thus, the aliphatic glycol is illustrated by ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, 1 2-butylene glycol, 2,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, or the like.Specific examples of the ethers include monophenyl ether of ethylene glycol, mono(heptylphenyl)ether of triethylene glycol, mono-(alpha-octyl-betanaphthyl-ether of tetrapropylene glycol, mono (polyisobutene(molecular weight of 1000)substituted phenyl) ether of octapropylene glycol, and mono-(o,p-dibutylphenyl)ether of polybutylene glycol, mono-(heptylphenyl)ether of trimethylene glycol and mono-(3,5dioctylphenyl)ether of tetra-trimethylene glycol, etc. The mono-aryl ethers are obtained by the condensation of a phenolic compound such as an alkylated phenol or naphthol with one or more moles of an epoxide such as ethylene oxide, propylene oxide, trimethylene oxide, or 2,3hexylene oxide. The condensation is promoted by a basic catalyst such as an alkali or alkaline earth metal hydroxide, alcoholate, or phenate.The temperature at which the condensation is carried out may be varied within wide ranges such as from room temperature to about 2500 C. Ordinarily it is preferably 5#1 500C. More than one mole of the epoxide may condense with the phenolic compound so that the product may contain in its molecular structure one or more of the radicals derived from the epoxide. A polar-substituted alkylene oxide such as epichlorohydrin or epibromohydrin likewise is useful to prepare the mono-aryl ether product and such product likewise is useful as an emulsifier.

Likewise useful as the emulsifiers are the mono- or di-alkyl ethers of the aliphatic glycols in which the alkyl radical preferably has 2 to 20 carbon atoms (e.g., octyl, nonyl, dodecyl, behenyl, etc.). The fatty acid esters of the mono-aryl or mono-alkyl ethers of aliphatic glycols also are useful. The acids include, e.g., acetic acid, formic acid, butanoic acid, hexanoic acid, oleic acid, stearic acid, behenic acid, decanoic acid, isostearic acid, linolenic acid, as well as commercial acid mixtures such as are obtained by the hydrolysis of tall oils, sperm oils, etc. Specific examples are the oleate of mono (heptylphenyl)ether of tetraethylene glycol and the acetate of mono-(polypropene(having molecular weight of 1000)-substituted phenyl)ether of tri-propylene glycol.

The alkali meal and ammonium salts of sulfonic acids likewise are emulsion stabilizers.

The acids are illustrated by decylbenzene sulfonic acid, di-dodecylbenzene sulfonic acid, mahogany sulfonic acid, heptylbenzene sulfonic acid, polyisobutene sulfonic acid (molecular weight of 750), and decylnaphthalene sulfonic acid, and tridecylbenzene sulfonic acid. The salts are illustrated by the sodium, potassium, or ammonium salts of the above acids.

Emulsifiers include phosphatides, especially those having the structural formula

wherein G is selected from the class consisting of fatty acyl radicals and phosphorus-containing radicals having the structural grouping

wherein R' is a lower alkylene radical having from 1 to about 10 carbon atoms and R" and R'7, are lower alkyl radicals having from 1 to 4 carbon atoms, and at least one but no more than two of the G radicals being said phosphorus-containing radicals. The fatty acyl radicals are for the most part those derived from fatty acids having from 8 to 30 carbon atoms in the fatty radicals such as octanoic acid, stearic acid, oleic acid, palmitic acid, behenic acid, myristic acid, and oleostearic acid.Especially desirable radicals are those derived from commercial fatty compounds such as soya bean oil, cotton seed oil, and castor seed oil. A particularly effective phosphatide is soyabean lecithin which is described in detail in Encyclopedia of Chemical Technology, Kirk and Othmer, volume 8, pages 309-326~(1952).

Also useful as supplementary emulsion stabilizers are the neutral alkali metal salts of fatty acids having at least 12 aliphatic carbon atoms in the fatty radical. These fatty acids include, principally, lauric acid, stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, linolenic acid, behenic acid, or a mixture of such acids such as are obtained from the hydrolysis of tall oil, sperm oil, and other commercial fats.

Only a small amount of the stabilizer is necessary for the purpose. It may be as little as 0.01 part and seldom exceeds 2 parts per 100 parts by weight of the electrolytic bath. In most instances it is within the range from 0.1 to 3 part per 100 parts of the bath.

As mentioned, the electropolymerization process utilized in this invention can be carried out in an organic diluent and more particularly in an organic phase containing less than about 3% and more preferably less than about 1% of water.

Examples of organic diluents include polyols, organic carbonates, ethers, nitriles, etc. It is essential that the solvent does not undergo competitive oxidation during the electropolymerization and thus interfere with dhe polymerization or substantially reduce the current efficiency of the polymerization process.

A preferred embodiment of the present invention, however, is the electropolymerization of pyrroles from aqueous media, either a singlephase aqueous system or a multi-phase aqueous system. Many of the advantages of using aqueous systems are apparent including, reduced costs, availability and easy purification of water, the ability to utilize a wide range of ionic materials as electrolyte salts in water, the ability to utilize high concentrations of ionic species thus permitting high electrochemical currents and high polymer formation rates. Under controlled conditions, intact homogeneous films of polypyrroles can be formed on a variety of substrates in aqueous media. Thicknesses range from less than 100 Angstroms to a few millimeters for more dense materials. In some instances, current density has an effect on the morphology.The morphology of the electropolymerized compositions of the invention can be further modified by the use of the additives already discussed.

It has been observed that improved results are obtained when the electroplating bath is thoroughly agitated during the electropolymerization of the monomers. Agitation can be accomplished by any known technique including vigorous stirring with paddle mixers, magnetic stirrers, ultrasonics, vibration or by bubbling gases through the bath to provide sufficient agitation (including gases generated at the counter-electrode). Electropolymerization is accomplished by passing an electric current through the bath at a voltage which is sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing a pyrrole at an electronically conductive surface immersed in the electrolytic bath. The electric current may be a continuous electric current or a varying electric current such as a pulse current.Generally, the electric current is direct current although in some instances alternating current may be useful.

The voltage at the anode should be sufficient to oxidize monomer without producing significant changes in the bath, such as degradation of a bath component, which would adversely affect the polymerization. Generally, current densities of up to two amperes per square centimeter may be used, but preferably, current densities not exceeding 500 milliamperes per square centimeter are utilized. In more preferred embodiments, the current density will be less than 250 and more generally, less than 100 milliamps per square centimeter.

At the above current densities, the pyrrole or co-polymerizable mixture of a pyrrole is electropolymerized at the electronically conductive surface Depending upon the specific ingredients in the plating bath, the electropolymerizable polypyrrole may either form as a powder at the electronically conductive surface and fall into and be dispersed in the electrolytic bath, or alternatively, be deposited on the conductive surface. The deposit may be in the form of a film which is either smooth and dense or irregular with less than the bulk or theoretical density. Bulk or theoretical density of the polymers is the density of continuous, pure polymer containing no voids, pores, cavities or inclusions. The bulk or theoretical density can usually be determined by flotation methods.

Examples of irregular deposits include porous films, powders, dendriform materials, etc. The nature of the cation(s) as well as that of the anion(s) present in the electrolytic bath affects the electropolymerization. The morphology of the deposit on the electronically conductive substrate can be controlled and modified by the incorporation in the electrolytic bath of various complexing agents for the ionic constituents of the electrolyte. Examples of materials which function as growth regulators when incorporated into the electrolytic bath include the abovediscussed non-ionic plasticizers (e.g. polyalkylene glycol such as polyethylene glycol), cryptands, and commercially available crown ethers such as 1 2-Crown-4, 15-Crown-S, and 1 8-Crown-6 available from Aldrich Chemical Co.

The temperature of the electrolytic bath during the electropolymerization process is generally maintained between about 15 to about 500 C, although polymerization proceeds over a much wider temperature range. The reaction is conducted at or about room temperature and preferably under thermostatted conditions.

A variety of electronically conductive substrates that do not undergo competitive oxidation during the electropolymerization can be utilized in the process of the invention. Not all types of metals can be used with the entire range of bath formulations. For example, although steel surfaces are useful for electropolymerizing pyrrole in the presence of sodium lauryl sulfate and water, the electrolytic bath containing pentaerythrityl tetrasulfate and water will not deposit a satisfactory film on steel, but deposits a satisfactory coating on nickel substrates. The choice of particular substrate material can be readily determined by those skilled in the art, with a minimum of experimentation. The size and shape of the substrate utilized in the process of the invention will vary depending upon the type of cell in which the electropolymerization process is conducted and on the desired form of the polymer. For example, when flat films are desired, the substrate will be in a shape of a flat panel in a parallel plate cell.

A preferred embodiment of this invention provides for a rotating cylindrical anode or a moving belt anode from which the polymer is removed in a continuous process. The polymer can also be collected or stripped from a stationary electrode in a continuous manner.

The time required to produce a given quantity or thickness of polymer will depend upon several factors, including the current density, bath temperature, size or physical dimensions of the electronically conductive surface anc: the temperature of the electrolytic bath. Moreover, the specific type of morphology desired will be an important consideration when selecting the values of the process variables such as temperature, current density, time of coating, voltage, etc.

One of the advantages of the process of the present invention, particularly with the aqueous systems of the invention, is the ability to produce films of controlled thickness over a wide range of thicknesses, and in particular, films having thicknesses greater than 250 micrometers, ard in particular thicknesses between a range of 0.5 mm. to 2 cm. Many prior art processes have not been developed to the level required to produce anything but thin films (200 micrometers or less).

In the general process of the invention, the electronically conductive surfaces are introduced into the electrolytic bath and connected to a current source. The polymer is formed at the anode. The counterelectrode may consist of the bath tank or a separate conductive surface(s) may be introduced into the electrolytic bath. The bath may have a separate compartment for the secondary electrode but the one compartment configuration is preferred.

When the electropolymerization process is completed, the substrate is removed from the electrolytic bath, and the electropolymerized material is mechanically stripped from the surface. This polymer may be washed with water and with various non-aqueous solvents (e.g., ethers, liquid hydrocarbons, etc.) to remove any undesirable deposits contained on or in the material. If the deposited material has not been fully dried, this can be achieved, if desired, by heating the polymer at elevated temperatures, preferably under vacuum. The particular temperatures will depend upon the nature of the pyrrole or co-polymerizable mixture of pyrroles utilized in the process, but will generally be less than 2500C and preferably below 1000C.

As mentioned earlier, the morphology and physical nature of the compositions electropolymerized in accordance with The method of the invention.will be dependent on a variety of factors including the nature of the substrate, solvent, temperature, agitation, current density, electric potential, etc. Continuous films having a density approximately equal to the bulk density of the polymer can be prepared by the process of the present invention when singlephase organic or aqueous systems are utilized.

When more irregular films characterized by low density and high surface area are desired, the multi-phase processes described above, in particular, the two-phase aqueous systems, are advantageous. In one of the preferred embodiments, the low mobility anions are incorporated into the compositions of the invention by including said anions in the electrolytic baths. When incorporated into the polymeric compositions of the present invention, the anions, as mentioned earlier, have low mobilities and ar substantially permanently retained in the polymer on reduction and on any subsequent oxidations or reductions.

One of the unexpected advantages of preparing the pyrrole polymers and co-polymers of the invention containing the low mobility anions is the fact that the polymer is able to be discharged and recharged through at least hundreds of cycles.

See, for example, Example 21. This is surprising since it might be expected that highly mobile anions would confer the greatest reversibility. The mechanism for the observed reversibility is not known but is believed t9 involve forced transport by other ion(s). Such compositions, therefore, are classified as being electrochemically reversible polymers, and they are, therefore, useful in the preparation of rechargable batteries.

The following examples illustrate the process of the invention. Unless otherwise indicated, all parts and percentages are by weight.

Unless otherwise indicated, in the following Examples, electropolymerizations are conducted at 2 amperes for 30 minutes using a Hanovia arc lamp power supply controlled with a Variac.

Agitation is accomplished with a horizontal perforated glass disk mounted on the bottom of a stirring rod (about 1 to 2 cm from the bottom of the bath) and rapidly vibrated up and down with A Vibro-Mixer (Model El, supplied by A. G. Fur Chemie-Apparatebau Mannedorf-Zurich). The temperature is controlled with an ice bath. Both electrodes are 1 5 x7.5 xO.05 cm panels of steel (AISI No. 10/10) in parallel plate configuration that have been degreased with toluene. The surface area (one side) of each electrode immersed in the bath is 70 cm2 and the distance between the electrodes is 5.5 cm. The polyethylene glycol used in some of the examples has an average molecular weight of about 1 5- 20,000. The bath is exposed to the atmosphere.

The descriptions of the polymer films of the following Examples do not cover edge effects.

These effects produce irregularities which rarely effect more than five percent of the total mass of the film.

Example 1 In this example, the following components are utilized: Grams Pyrrole 40 Sodium Lauryl Sulfate 40 Polyethylene Glycol 20 Distilled Water 1600 Heptane 200 (ml.) The above first four ingredients are mixed in a container until homogeneous, and 375 ml. of this mixture is added to the 10.8x8.9x5.7 cm.

reaction vessel. Two steel panel electrodes are put into place. Heptane (50 ml.) is added, and agitation is accomplished mechanically with a Vibro Mixer.

Four films are separatedly prepared at 2 amperes utilizing a reaction time of 30 minutes. The temperature is controlled with an ice bath and is initially 21 0C and rises to a temperature of about 34~37 C during the reaction. The current is maintained at 2 amperes, but the voltage changes from about 60 to about 40 volts during the course of the reaction. The electrolyte side of each film has a few irregularities in the form of dendriform projections (about 1 millimeter) and these projections are removed by light abrasion before stripping the films from the electrode surfaces.

Each film is rinsed thoroughly in distilled water and in heptane.

Two of the films are fully dried in a vacuum oven at 500C for 24 hours. The cleaned films obtained in this manner appear to comprise 3 layers. The first layer which is the layer closest to the steel panel is smooth and continuous. The second layer adjacent to the smooth layer is a uniformly porous material and the third layer adjacent to the second layer is denser and less porous than the seond layer. The two other films obtained in this example are stripped of their backing or smooth layer and cut into 3/4 inch strips. The strips are cleaned in a soxhlet extractor with distilled water for 15 hours. After drying at room temperature, the pieces are further dried in a vacuum oven at 500C for 24 hours Example 2 A mixture of 5 grams of pyrrole, 1 gram of sodium ethane disulfonate, 2 grams of polyethene glycol and 200 grams of water is prepared and added to an 8x7x4.5 cm reaction vessel.The cathode is a 15x5x0.025 cm piece of Precision brand shim steel (a product of Precision identified as NIDA/SIDA 1613D Al). The anode is a 10x5x0.05 cm Nickel 200 panel. (Nickel 200 is product of Inco identified as a high purity nickel).

The surface area (one side) of each electrode immersed in the bath is about 40 cm2. Toluene (20 ml.) is added and the mixture agitated using a Vibro-Mixer. The electropolymerization reaction is conducted for 15 minutes at a constant current of 0.5 amperes at a potential of about 17 volts. The film formed on the electrode is removed and observed to be a relatively porous uniform film of about 0.3 to 0.4 mm in thickness.

Example 3 A mixture of 20 grams of pyrrole, 4 grams of pentaerythrityl tetrahydrogensulfate, 4 grams of polyethylene glycol and 800 grams of water is prepared and mixed until homogeneous. A volume of 375 ml. is added to a 5.7x8.9x10.8 cm reaction vessel, and 50 ml. of dichloromethane also is added to the vessel. In this example, a panel of steel (AISI No. 10/10) (1 5x7.5x0.05 cm) is used as the cathode, and a Nickel 200 sheet (14.2x7.6x0.025 cm) is used as the anode. The electropolymerization is carried out in a normal manner over a period of 15 minutes while maintaining a current of 2 amperes. A porous mass of approximately 1 cm in thickness with a low density (less than 0.1 g cm~3) is obtained; this porous mass is electronically conducting.

Example 4 A mixture of 20 grams of pyrrole, 10 grams of sodium-1 ,1 0-decane disulfonate, 10 grams of polyethylene glycol and 800 parts of water is prepared, and 375 ml. added to each of two reaction vessels. Heptane, (50 ml.) is added to each reaction vessel, and the electropolymerization carried out in the normal manner at a current of 2 amperes. The electropolymerization in the first reaction vessel is terminated after 5 minutes yielding a thin black electronically conductive film covered with small dendriform projections of about 1 mm. in height.

The electropolymerization reaction in the second vessel is carried out for 39 minutes yielding a thicker base film covered with small dendriform projections of approximately the same dimensions as for the previous film.

Example 5 A mixture of 10 grams of pyrrole, 10 grams of sodium lauryl sulfate and 0.5 grams of polyethylene glycol is prepared and added to the reaction vessel. In this example, both electrodes are steel panels and agitation is accomplished with a Vibro Mixer. The electropolymerization reaction is conducted for 20 minutes at a current of 2 amperes. A thick rather uniform coating is deposited on the anode and the coating is covered with small dendriform shapes which are easily removed by light abrasion.

Example 6 The procedure of Example 5 is repeated except that 50 ml. of heptane is added to the mixture in the reaction vessel, and the electropolymerization is conducted for five minutes at 2 amperes. The film prepared in this manner is more porous than the material obtained from the procedure of Example 5 and is covered with dendriform shapes.

Example 7 Pentaerythrityl tetrasulfate ammonium salt is prepared from pentaerythritol and sulfamic acid in N,N-dimethylformamide. A mixture of 5 grams of pyrrole and 5 grams of the ammonium salt in 200 ml. water is prepared and electropolymerized in a 8x7x4.5 cm reaction vessel wherein the cathode is a 15x5x0.025 cm Precision brand steel sheet and the anode is a 6.4x5x0.025 cm nickel sheet.

About 40 cm2 of the nickel sheet is immersed in the bath. The distance between electrodes is 4.5 centimeters. Electropolymerization is conducted at a current of 0.3 amperes for a period of 10 minutes yielding a black electronically conducting film characterized by a somewhat rough surface on the solution side of the film.

Example 8 The procedure of Example 7 is repeated except that 2 grams of polyethylene glycol is included in the mixture contained in the reaction vessel. The black electronically conducting film obtained in this manner is more uniform and smoother on the solution side than the film obtained in Example 7.

Example 9 Mannityl hexasulfate ammonium salt is prepared from mannitol and sulfamic acid in dimethylformamide. A mixture of 5 grams of pyrrole and 1 gram of this ammonium salt is dissolved in 200 ml. of water. Utilizing the apparatus described in Example 7, the electropolymerization is carried out at a current of about 0.4 amperes over a period of 20 minutes.

The product is a black electronically conducting film which is shiny on the substrate side and rough on the solution side.

Example 10 The procedure of Example 9 is repeated except that 2 grams of polyethylene glycol is added to the mixture in the reaction vessel. A more uniform film is obtained in this example which is much smoother on the solution side.

Example 11 A mixture of 15 grams of pyrrole in 500 grams of water is prepared, and a second mixture of 10 grams of potassium ferricyanide and 5 grams of polyethylene glycol is prepared in 400 ml. of water. The two solutions are mixed together and shaken. Approximately 450 ml. of the mixture is poured into the 10.8x8.9x5.7 cm reaction vessel. The electrodes used in this example are both steel panels. The electropolymerization is conducted at 5 amperes. At the start of the reaction the temperature is 230C and the voltage is 22 volts. During the electropolymerization reaction, the temperature is stabilized at 31320C with an ice bath. At this temperature, 20 volts is required to maintain a current of 5 amperes. The distance between electrodes is 5.5 cm. The electropolymerization reaction is conducted for 40 minutes. The polymer is then removed from the anode.This film is 0.8 mm.

thick, black and electronically conducting. The film is smooth on both sides although smoother on the substrate side.

Example 12 The procedure of Example 11 is repeated except that the 1 5,000-20,000 molecular weight polyethylene glycol is replaced by an equivalent weight of Carbowax 4000 (a product of Union Carbide identifed as 4,000 molecular weight polyethylene glycol). The electropolymerization reaction is conducted at 5 amperes current and about 20 volts are required to maintain this current throughout the 40 minute reaction period. The temperature of the bath ranges from 220 to 320C. The polymer is removed from the electrode, and the film obtained in this manner is black and electronically conducting. The substrate side is smooth while the solution side is covered with dendriform structures.

Example 13 A mixture of 2 grams of pyrrole, 0.4 grams of a 50% aqueous solution of the sodium salt of 2 acrylamido-2-methylpropanesulfonic acid and 1 00 ml. of water is prepared and mixed until homogeneous. In this example, the cathode of the reaction vessel is a platinum strip (0.5x3 cm.) and the anode is a gold surface (2x4 cm) with about 4 cm2 immersed in the bath. The electrodes are rinsed with distilled water prior to use. The electropolymerization in this example is carried out using a Hewlett Packard power supply/amplifier Model 6824A. The electropolymerization reaction is conducted at a current of 24 milliamps and at a voltage of 1 5 volts for a period of 2 minutes. A thin black electronically conductive film is deposited on the gold surface.

Example 14 The procedure of Example 13 is repeated except that the electrolyte salt utilized is poly(2 acrylamido-2-methylpropanesu Ifonic acid sodium salt having an inherent viscosity of 0.1 dl. g*-t (measured in 0.5 N NaCI at 300C). The electropolymerization is conducted at 30 milliamps at 20 volts for a period of 2 minutes. A smooth thin glossy black electronically conducting film is deposited on the gold surface.

Example 15 A mixture of 20 grams of pyrrole, 20 grams of sodium lauryl sulfate, 10 grams of polyethylene glycol and 800 grams of water is prepared, and 375 ml. of this mixture is added to the 10.8x8.9x5.7 cm reaction vessel. Heptane (50 ml.) for each experiment is then added to the reaction vessel, and agitation is accomplished with a rapidly vibrating glass disk. The temperature is controlled with an ice bath. In this example, the electropolymerization is carried out using a current of 2 amperes. The reaction time is 30 minutes and the reaction temperature ranges from 200--380C. The polymer formed on the anode is removed and cleaned by washing several times in distilled water.The film prepared in this manner comprises a very thin base layer next to the substrate, a uniformly porous layer adjacent the base layer and a denser wrinkled less porous layer on the electrolyte side. The polymer layer is removed from the electrode and a 4x 1 cm strip is cut from the film and its thin base layers removed.

The rest of the film is broken into pieces and rinsed several times with distilled water along with the strip. The pieces and the strip are then rinsed further in a Soxhlet extractor using distilled water for 1 5 hours (about 40 extractions). The materials are then dried in a vacuum oven at 800C for 29 hours. This polymer is electronically conducting and can be ground dry to a porous powder which is easily cold pressed without any additives into various shapes as desired. The shapes obtained in this manner are also electronically conducting.

Example 16 The procedure of Example 15 repeated except that the mixture contains only 7.5 grams of polyethylene glycol. The electropolymerization of the mixture results in a thinner, denser film than obtained in Example 15. The film also does not appear to be as flexible and the corresponding powder does not cold press as well as the powder obtained in Example 15.

Example 17 The procedure of Example 1 5 is repeated except that the mixture contains only 5 grams of polyethylene glycol. The film obtained in this manner is electronically conductive, is thinner than the film obtained in Example 16 and is less uniform.

Example 18 A mixture of 40 grams of pyrrole, 40 grams of sodium lauryl sulfate, 1 5 grams of polyethylene glycol and 1,600 grams of water is agitated until homogeneous, and 1200 ml. is added to a 8.25x 14x 19 cm plastic reaction vessel. Both electrodes are 14x19x0.1 cm panels of steel (AISA No. 10/10) steel plate degreased with toluene. Heptane (15) ml.) is added and agitation is accomplished with a Vibro Mixer. The surface area of the anode covered with polymer is about 250 cm2. The electropolymerization reaction is conducted for a period of one hour at a current of about 4 amperes D.C. The product is removed from the anode and partially pulverized by hand while washing with distilled water.After further washing (Soxhlet extraction with distilled water) and drying, (vacuum oven, 850C, 20 hr.) the polymer was pulverized further with a mortar and pestal. In this rnanner, fine black electronically conducting powder is obtained.

The powder obtained in this example can be cold pressed at room temperature in the dry state without any additives, and the pressed electrodes obtained in this manner exhibit improved electronc conductivity over the dried electropolymerized films. The density of the electropolymerized film is about 0.2 g cm-3 whereas the density of the pressed electrode is about 0.8 g cm~3.

Example 19 The procedure of Example 18 is repeated except that the power source is a simple full wave rectifier (12 amp rating) controlled with a Variac.

The voltage requirements are essentially identical to those of Example 18.

Example 20 An electrolyte bath is prepared comprising 1 g of phenyl phosphonic acid and 2 g of pyrrole in 100 g of water. The electropolymerization is carried out in the unstirred bath on a gold strip of dimensions 3 cmx0.5 cm. The gold strip is immersed to a depth of 1 cm. A platinum counterelectrode is employed and a current of 1 milliampere is maintained for 300 seconds. The product is a black electronically conducting film.

In particularly advantageous embodiments polymers or co-polymers of the invention can be heat treated to enhance their electrochemical storage capacities. Heat treatment is preferably conducted at a temperature above the transition temperature of the composition observed during differential scanning calorimetry (DSC) in the region of about 600 C. For example, a temperature in the range of about 600C up to the decomposition temperature of the polymer, preferably about 800C to abou#t 1 000C, can be used. Heat treatment is preferably conducted under a vacuum or partial vacuum (e.g., a pressure of about 1 mm Hg. absolute or less) and is continued until equilibrium is achieved or substantially achieved (e.g., about 10 to about 20 hours).

The electronically conductive polymers or copolymers prepared in accordance with this invention are useful, for example, for electrodes in electrochemical cells (e.g., as electrodes in batteries, both primary and secondary batteries); as coatings for photocells to inhibit photocorrosion or corrosion processes; for catalytic electrodes; for electric conductors; for conductive substrates and/or binders and mixtures for composite electrodes; for switching devices; and as durable or corrosion resistant electropolymerized coatings. The electronically conductive polymers of the invention are also useful in solid state applications (e.g., in the formation of junctions) and/or for photovoltaic and photoelectrochemical devices and as reversible electrode materials in electrochemical cells and batteries.

Electrodes produced in accordance with the present invention may be positive or negative and may contain in addition to polymer, a suitable binder material and/or suitable high surface area carbon materials. They may also contain at least one other redox species. Suitable binder materials are inert polymeric binders that do not hinder the electrochemical performance of the resulting electrode. An example of such a binder material is a halogenated polymeric material such as polytetrafluoroethylene which is preferably introduced from an aqueous suspension, such suspension being available commercially, for example, from DuPont under the trade designation Teflon T30B. Polytetrafluoroethylene introduced in the form of a powder may be used.

Other polymers, for example polypropylene, may be suitable for use in such compositions under conditions that are not strongly oxidizing. High surface area carbons that are suitable are those materials having surface areas of about 1 to about 2000 square meters per gram, preferably about 60 to about 1200 square meters per gram.

Examples of commercially available high surface area carbons that are useful are RB Carbon identified as having a surface area of about 1200 square meters per gram, and Shawinigan Black identified as having a surface area of about 60 to about 65 square meters per gram.

Polymeric electrodes can be prepared in accordance with the invention by mixing a polymer of the invention together with the optional ingredients of binder, high surface area carbon and/or other redox species with water or organic liquid (e.g., mineral spirits) to provide a paste-like mixture. The paste-like mixture is then cold pressed or rolled according to standard techniques preferably at a pressure in the range of about 500 to about 12,000 PSI and a temperature in the range of about room temperature to the decomposition temperature of the polymer, to provide an electrode of desired shape. The polymer is preferably heat treated to increase its electrochemical storage capacity prior to or subsequent to being incorporated into the mixture.

The polymeric electrodes provided in accordance with the present invention either as anodic films or pressed from powders are suitable for use in electrochemical cells, particularly electrochemical storage cells or batteries (both primary and secondary batteries) as the positive and/or negative electrode. These electrodes can have any desired size and shape, such size and shape depending upon the size and shape of the electrochemical cell or battery for which they are used.

In electrochemical cells wherein the polymeric material of the invention is the positive electrode, a metal negative electrode can be used. The metal negative electrode is designed and constructed in accordance with standard practice and preferably is an alkali metal or an alkaline-earth metal or an alloy of either. Preferred alkali metals are lithium, sodium and potassiun. Preferred alkaline-earth metals are magnesium and calcium. Suitable alloying materials are aluminum and silicon, for example.

In electrochemical cells wherein the polymeric material of the invention is the negative electrode, the positive electrode can be made of any material (i.e., metal or non-metal) provided such positive electrode is electrochemically more positive than the polymeric negative electrode of the invention, Both polymeric positive and negative electrodes can be provided in an electrochemical cell in accordance with the present invention.

These electrodes may have different compositions or can have the same composition and/or be made in accordance with the same method, provided such electrodes can accommodate sufficiently different charge states to provide an effective electrochemical cell. The polymeric electrodes (negative and positive) provided in accordance with the present invention preferably comprise porous electronically conducting compositions comprising an electropolymerized polypyrrole or co-polymer of a pyrrole having an apparent density of from about 0.1 g cm-3 up to about the bulk density of the polypyrrole or copolymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.These electrodes preferably contain one or more low mobility anions characterized by an average ionic transference number during reduction of less than about 0.1, preferably less than about 0.01. An advantage of the positive electrodes comprising the polymers provided in accordance with the present invention is that electronic resistance of such electrodes increases as the discharge voltage of the cell approaches zero volts thus tending to protect the electrochemical cell from damage resulting from overdischarge.

Referring to the drawings, Fig. 1 illustrates a laboratory scale flooded lithium cell with an outer large container 1 having a cap 2. The cap 2 is constructed with a hole in the center in which a rubber stopper 3 is inserted. Within the large container 1 is a smaller container 4 held in place by rubber flange 14. The elements of the lithium cell are maintained in the small container 4. the larger container 1, cap 2 and stopper 3 being utilized to maintain a specific atmosphere such as argon. The desired atmosphere such as argon is introduced through plastic tubing inserted through the stopper as indicated at 10, and the argon exits through tube 11.A strip of the polymer of the invention 6 is suspended within the inner container 4 using nickel contacts 13, and two lithium electrodes 5 and 9 also are suspended through the stopper 3 into the inner container 4 through the use of platinum hooks 8.

The polymer electrode 6 is a positive electrode whereas lithium electrode 5 is a working negative electrode and lithium electrode 9 is a reference electrode. Working electrode 5 is larger than the reference electrode 9. Sufficient non-aqueous electrolyte 12 is added to the inner container 4 to provide an electrolyte level 15 below the platinum hooks 8 and covering a portion of the positive electrode 6 and the two lithium electrodes 5 and 9.

The reversible storage of charge in the materials of the present invention is also demonstrated in a flooded cell in an argon filled glove box, Fig. 2. The glass container 30 holds 50 ml. of non-aqueous electrolyte 31. A strip 32 of the polymer of the present invention is suspended between strips 33 and 34 of active lithium metal, and is in electrochemical ionic communication with strips 33 and 34 by means of the electrolyte 31. Lithium electrode 33 is a negative electrode and acts as a source (during discharge) and a sink (during charge) of lithium ions. Lithium electrode 34 is placed in close promixity to the strip 32 and serves as a reference electrode; no current flows through electrode 34.

When active metals such as lithium, sodium or calcium are used as negative electrodes, nonaqueous electrolytes are used. Typically, these electrolytes are organic liquids which have salts of the electroactive species dissolved in them. For example, in the case of cells employing lithium negative electrodes, well known electrolytes are used such as propylene carbonate/I .0M lithium perchlorate (PC/1.0M Lilo4), tetrahydrofuran/1.5M lithium hexafluoroarsenate, 2M e-tetrahydrofuran/1 .0M lithium hexafluoroarsenate, mixtures thereof, etc.

The present invention also includes primary and secondary batteries, Figs. 3 and 4, which include negative alkali metal electrode 45 (e.g., lithium, sodium or potassium); separator 46; polymeric positive electrode 47 which is prepared in accordance with the present invention; ceramic or glass feed-through insulator 49; spacers 50 and 51, and metal negative electrode contact 52.

Metallic casing 48 provides containment of the cell components and electrical contact to the positive electrode 47. Negative electrode 45 is electronically isolated from the positive electrode contact 48 by the insulator 49. Alternatively, cell containment can be provided by an insulating material such as plastic, and electrical contact can be made to the electrode by means of metallic grids, screens, foils, etc. In a preferred embodiment a cylindrical wrapping of the negative electrode 45, separator 46, and positive electrode 47 into a cell having a spiral-wound configuration is provided.

Another preferred embodiment of the present invention Fig. 5, is laboratory-scale electrochemical energy storage cell 60 which has a layered configuration and includes polymeric positive electrode 61 which is prepared in accordance with the present invention, lithium negative electrode 62, lithium reference electrode 63, glass fiber separators 64, gold contacts 65, 66 and 67, glass plates 68 and 69 and epoxy seal 70. The cell is assembled in dry air or in an inert atmosphere, for example, argon.

Another preferred embodiment of the present invention includes layered or stacked cell 71 (Fig.

6) in which a number of positive and negative electrodes are respectively connected in parallel for purposes of increasing the maximum current that can be supplied by the resulting battery package. Cell 71 includes parallel spaced polymeric electrodes 72and, which are provided in accordance with the present invention, and parallel spaced negative electrodes 73aid which are parallel to and spaced from electrodes 72a-d. Electrodes 72 and 73 are housed within container 74. Container 74 is preferably electronically insulating. Electrode 73a is positioned in parallel spaced relationship between electrodes 72a and 72b. Electrode 73b is positioned in parallel spaced relationship between electrodes 72b and 72c. Electrode 73c is positioned in parallel spaced relationship between electrodes 72c and 72d.Electrode 73d is positioned in parallel spaced relationship below electrode 72d. Electrodes 72aid are connected to contact 76 which projects from container 74.

Similarly, electrodes 73aid are connected to contact 77 which projects from container 74.

Separator material 75, which contains a suitable electrolyte, is dispersed throughout the interior of container 74. Although four electrodes 72and and four electrodes 73and are shown in the illustrated embodiment, it will be understood by those skilled in the art that the number of such electrodes can be fewer or greater than four, such number being dependent upon the requirements for cell 71.

In still another embodiment of the present invention, layered or stacked cell 81 (Fig. 7) is provided in which a series stack of alternating positive and negative electrodes gives a bipolar configuration for the purposes of increasing the total voltage of the resulting battery package. Cell 81 includes parallel spaced polymeric electrodes 82and, which are provided in accordance with the present invention, and parallel spaced negative electrodes 83acid which are parallel to and spaced from electrodes 82and, respectively.

Separators 84and which can be made of fiberglass, for example, and contain a suitable electrolyte are positioned between electrodes 82aid and 83aid as shown. Electrodes 82aid and 83a-d and separators 84acid are housed within electronically insulating container 85.

Container 85 also includes bipolar electronically conductive plates 86, 87 and 88 which divide container 85 into four isolated compartments 90, 91,92 and 93. Electrodes 82a and 83a, and separator 84a are positioned in compartment 90.

Electrodes 82b and 83b and separator 84b are positioned in compartment 91. Electrodes 82c and 83c and separator 84c are positioned in compartment 92. Electrodes 82d and 83d and separator 84d are positioned in compartment 93.

Contact to the two ends of the series stack is provided by contacts 95 and 96 which project from container 85. Although four electrodes 82aid and four electrodes 83a d are shown in the illustrated embodiment, it will be understood by those skilled in the art that the number of such electrodes can be fewer or greater than four, such number being dependent upon the requirements forcell 81.

Example 21 The composition of Example 6 is used as a positive electrode material in lithium cell 60, the design of cell 60 being depicted in Fig. 5. The cell 60 is assembled in a dry argon atmosphere. The polymer composition 61 is electropolymerized on a gold strip which serves as contact 65. The thickness of each separator 64 is about 0.5 mm.

Separators 64 are soaked with electrolyte, 1 M Lilo4 in propylene carbonate. Negative electrode 62 and reference electrode 63 are formed from lithium. The cell 60 sandwiched between glass plates 68 and 69 as shown, is clamped together and the edges sealed with epoxy 70.

A thin film of polymer is prepared in accordance with Example 6, with the exception that it is electropolymerized for a shorter time.

The film is tested as the positive electrode in cell 60.

The areal density of the film is about 0.1 mg cm~2. The discharge is carried out at a current of about 0.1 mA-cm2, and is terminated when the potential between the positive electrode 61 and the reference electrode 63 drops to about 1 volt.

At this point the polymer demonstrates a specific capacity of 19 Ah (kg polymer)-1.

This cell is repeatedly recharged and discharged under constant current conditions, and exhibits good reversibility over more than 200 cycles. The performance of this cell was not degraded despite repeated overdischarging and repeated overcharging on the order of the capacity of the cell. The open circuit voltage of this type of cell when tested over a period of four months shows little or no degradation.

Example 22 The composition of Example 11 is used as the positive electrode material in the cell described in Example 21. A thin electropolymerized film of areal density of about 0.25 mg cm-2 is discharged at a current of about 0.25 mA cm~2. The discharge is terminated when the potential between the polymer and the reference electrode drops to about 1 volt. This composition exhibits a specific capacity of 83 Ah (kg polymer)~'.

Example 23 A porous composition prepared according to Example 1 is used as the positive electrode material in the cell of Fig. 1. The self supporting film has approximate dimensions of 2x0.8x0.1 cm and a weight of about 48 mg. The discharge is carried out at a total current of 2 milliamperes, and terminated when the overall cell voltage (between electrodes 5 and 6) drops to 1 volt.

This material demonstrates a specific capacity of about 35 Ah (kg polymer)-1 and can be charged and discharged in excess of 220 cycles.

Example 24 The composition produced by the method of Example 15 is used as positive electrode material in the cell illustrated in Fig. 2. The negative electrode material is lithium and the electrolyte is 1 M Lilo4 in propylene carbonate. The cell is discharged at a current of 1 mA cm and the discharge is terminated when the overall cell voltage falls to 1 volt. The material demonstrates a reversible specific capacity of 57 Ah (Kg polymer)-1.

Example 25 The composition produced by the method in Example 16 is used as positive electrode material in the cell illustrated in Fig. 2. The negative electrode material is lithium and the electrolyte is 1 M Lilo4 in propylene carbonate. The cell is discharged at a current of 1 mA cm~2 and the discharge is terminated when the overall cell voltage falls to 1 volt. The material demonstrates a reversible specific capacity of 59 Ah (kg polymer)#1.

Example 26 A porous composition prepared according to Example 1 is heat treated at 800C and a pressure of about 1 mm Hg absolute for 12 hours.

Example 27 Example 23 is repeated with the exception that the product of Example 26 is used as the positive electrode material in the cell of Fig. 1. This material demonstrates a specific capacity of about 57 Ah (Kg polymer)-1.

While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications that fall within the scope of the appended claims.

Claims

1. A porous electronically conducting composition comprising an electropolymerized polypyrrole or a co-polymer of a pyrrole, said composition characterized by an apparent density of from about 0.019 cm-3 up to about the bulk density of said polypyrrole or co-polymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.

2. The composition of claim 1 wherein said composition is heat treated to enhance the electrochemical storage capacity of said composition.

3. The composition of claim 1 in the form of a homogeneous porous film, or a powder of which the particles are porous.

4. A porous electronically conducting composite composition comprising at least two members, at least one of which comprises the porous electronically conducting composition of claim 1.

5. The composition of claim 1 wherein the density of the composition is from about 0.2g cm to about 0.89 cm~3.

6. The composition of claim 1 also containing at least one low mobility anion characterized by an average ionic transference number during reduction of less than about 0.1

7. The composition of claim 6 wherein the average transference number is less than 0.05.

8. The composition of claim 6 wherein the anions are organic anions.

9. The composition of claim 8 wherein the organic anions are derived from organic sulfates or sulfonates.

10. The composition of claim 9 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

1 The composition of claim 10 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

12. The composition of claim 1 1 wherein the sulfate is lauryl sulfate.

13. The composition of claim 6 wherein the anion is derived from a sulfated polyhydroxy compound.

14. The composition of claim 13 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

15. The composition of claim 6 wherein the anions are derived from pentavalent phosphorous compound.

16. The composition of claim 15 wherein said phosphorous compound is phosphate.

17. The composition of claim 15 wherein said phosphorous compound is phosphonate.

18. The composition of claim 15 wherein said phosphorous compound is phosphinate.

19. The composition of claim 1 or 6 also containing at least one plasticizer.

20. The composition of claim 19 wherein the plasticizer is a polyhydroxy compound.

21. The composition of claim 19 wherein the plasticizer is a polyalkylene glycol.

22. The composition of claim 1 or 6 comprising a redox species.

23. The composition of claim 22 wherein the redox species is a transition metal complex.

24. The composition of claim 6 wherein the anion is also a plasticizer for the composition.

25. An electronically conducting composition comprising electropolymerized polypyrrole or a co-polymer of pyrrole, said composition containing one or more low mobility anions characterized by an average ionic transference number for said low mobility anions during reduction of less than about 0.1.

26. The composition of claim 25 wherein said composition is heat treated to enhance the electrochemical storage capacity of said composition.

27. The composition of claim 25 wherein said ionic transference number is less than 0.05.

28. The composition of claim 25 in the form of a homogeneous coherent smooth film of bulk density or a uniformly porous film of less than bulk density.

29. The composition of claim 25 wherein the anions are derived from organic sulfates or sulfonates.

30. The composition of claim 29 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

31. The composition of claim 25 wherein the anion is an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

32. The composition of claim 31 wherein the alkyl sulfate is lauryl sulfate.

33. The composition of claim 25 wherein the anion is derived from a sulfated polyhydroxy compound.

34. The composition of claim 33 where the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

35. The composition of claim 25 wherein the anions are derived from pentavalent phosphorous compound.

36. The composition of claim 35 wherein said phosphorous compound is phosphate.

37. The composition of claim 35 wherein said phosphorous compound is phosphonate.

38. The composition of claim 35 wherein said phosphorus compound is phosphinate.

39. The composition of claim 25 also containing at least one plasticizer.

40. The composition of claim 39 wherein the plasticizer is a polyhydroxy compound.

41. The composition of claim 39 wherein the plasticizer is a polyalkylene glycol.

42. The composition of claim 25 comprising a redox species.

43. The composition of claim 42 wherein the redox species is a transition metal complex.

44. The composition of claim 25 wherein the anion is also a plasticizer for the composition.

45. A method of preparing electronically conducting polypyrrole or co-polymer of pyrrole which comprises electropolymerization of pyrrole or a co-polymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath comprising the steps: A. immersing an electronically conductive surface in an electrolytic bath comprising at least one liquid and at least one non-miscible liquid or gas or finely divided solid particles wherein a pyrrole or co-polymerizable mixture containing a pyrrole is one of the liquids or is dissolved in at least one of the liquids, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing a pyrrole at the electronically conductive surface.

46. A method of preparing electronically conducting polypyrrole or a co-polymer of pyrrole which comprises electropolymerization of pyrrole or a co-polymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath comprising the steps: A. immersing an electronically conductive surface in an electrolytic bath comprising at least one liquid and at least one non-miscible liquid or gas wherein the pyrrole or co-polymerizable mixture containing a pyrrole is one of the liquids or is dissolved in at least one of the liquids, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing pyrrole at the electronically conductive surface.

47. The method of claim 46 wherein the electric current is continuous or varying.

48. The method of claim 46 wherein the bath is agitated while the electric current is passed through said bath.

49. The method of claim 46 wherein the polypyrrole or co-polymer of a pyrrole is deposited on the conductive surface.

50. The method of claim 46 wherein the polypyrrole or co-polymer of pyrrole is formed as a powder at the electronically conducting surface and is dispersed in the bath.

51. The method of claim 46 wherein the electrolytic bath comprises pyrrole, water, and a water-immiscible organic diluent.

52. The method of claim 51 wherein the bath also contains an emulsifier.

53. The method of claim -51 1 wherein the polypyrrole or co-polymer of pyrrole is formed as a powder at the conducting surface and the powder is dispersed in the bath.

54. A method of preparing electronically conducting polypyrrole or a co-polymer of a pyrrole which comprises the steps of A. electropolymerizing a pyrrole or a copolymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath by

1. immersing an electronically conductive surface in an electrolytic bath which comprises (a) an aqueous dispersion of a pyrrole, or a mixture of said aqueous dispersion and at least one co-polymerizable monomer, or (b) a pyrrole or a mixture of a pyrrole and/or at least one co-polymerizable monomer, water and water-immiscible diluent,

2. agitating the bath, and

3. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or a pyrrole mixture and deposit the polymer or co-polymer on the electronically conductive surface, and B. removing said polymer or co-polymer from the conductive surface.

55. The method of claim 54 wherein the electrolytic bath is maintained at a temperature of from about 1 50 to 500C as the electric current is passed through the bath.

56. The method of ciaim 54 wherein the electric current is a continuous or varying electric current.

57. The method of claim 54 wherein the electric current is a direct current.

58. The method of claim 54 wherein the electrolytic bath also contains an emulsifier.

59. The method of claim 54 wherein the electrolytic bath comprises at least about 50% by weight of water.

60. The method of claim 45 or 54 wherein the electrolytic bath also contains one or more low mobility anions which are incorporated into the polypyrrole or co-polymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of less than 0.1. -

61. The method of claim 59 wherein said ionic# transference number is less than 0.05.

62. The method of any one of claims 45, 46 or 54 with the step of heat treating said electronically conducting polypyrrole or copolymer of pyrrole to enhance the electrochemical storage capacity thereof.

63. The method of claim 60 wherein the anions in the bath are derived from organic sulfates or sulfonates.

64. The method of claim 63 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

65. The method of claim 60 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

66. The method of claim 60 wherein the anion is derived from a sulfated polyhydroxy compound.

67. The method of claim 66 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

68. The method of claim 60 wherein the anions are derived from pentavalent phosphous compound.

69. The method of claim 68 wherein said phosphorous compound is phosphate.

70. The method of claim 68 wherein said phosphorous compound is phosphonate.

71. The method of claim 68 wherein said phosphorous compound is phosphinate.

72. The method of claim 45 or 54 wherein the bath also contains a plasticizer.

73. The method of claim 72 wherein the plasticizer is a polyhydroxy compound.

74. The method of claim 72 wherein the plasticizer is a polyalkylene glycol.

75. The method of claim 45 or 54 wherein the bath comprises a redox species.

76. The method of claim 75 wherein the redox species is a transition metal complex.

77. The method of claim 45 or 54 wherein the bath also contains a neutral or ionic surface active compound.

78. The method of claim 60 wherein the anion also is a plasticizer for the polypyrrole or copolymer of pyrrole.

79. A method of preparing electronically conducting polypyrrole or co-polymerof pyrrole which comprises electropolymerization of pyrrole or a co-polymerizable mixture containing pyrrole at an electronically conductive surface in an electrolytic bath comprising the steps of A. immersing an electronically conductive surface in an electrolytic bath comprising an aqueous mixture comprising pyrrole or a mixture of pyrrole and a co-polymerizable monomer and water, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing pyrrole at the electronically conductive surface.

80. The method of claim 79 wherein the bath is agitated while the electric current is passed through said bath.

81. The method of claim 79 wherein the polypyrrole or co-polymer of polypyrrole is deposited on the electronically conductive surface.

82. The method of claim 79 wherein the polypyrrole or co-polymers of pyrrole is formed as a powder at the conductive surface and dispersed in the bath.

83. The method of claim 79 wherein the bath also contains a neutral or ionic surface active compound.

84. The method of claim 79 wherein the bath also contains an emulsifier.

85. The method of claim 79 wherein the bath also contains one or more low mobility anions which are incorporated into the polypyrrole or copolymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of less than 0.1.

86. The method of claim 85 wherein said transference number is less than 0.05.

87. A method of preparing electronically conducting polypyrrole or co-polymer of pyrrole which comprises the steps of A. electropolymerizing a pyrrole or a copolymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath by

1. immersing an electronically conductive surface in an electrolytic bath which comprises an aqueous mixture comprising pyrrole or a co-polymerizable mixture of pyrrole, water, and one or more low mobility anions which are incorporated into the polypyrrole by electropolymerization and which anions are characterized by an average ionic transference number on reduction of less than 0.1,

2. agitating the bath, and 3. passing an electric current through the said bath at a voltage sufficient to electropolymerize the pyrrole or pyrrole mixture and deposit the polymer or co polymer on the electronically conductive surface, and B. removing said deposit from the conductive surface.

88. The method of claim 87 wherein the transfer number change on discharge is less than 0.05.

89. The method of claim 87 wherein the electrolytic bath is maintained at a temperature of from about 150 to 50 C as the electric current is passed through the bath.

90. The method of claim 87 wherein the electric current is a direct current.

91. The method of claim 79 or 87 with the step of heat treating said electronically conducting polypyrrole or co-polymer of pyrrole to enhance the electrochemical storage capacity thereof.

92. The method of claim 87 wherein the anions in the bath are derived from organic sulfates or sulfonates.

93. The method of claim 92 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

94. The method of claim 93 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atom in the alkyl group.

95. The method of claim 87 wherein the anion is derived from a sulfated polyhydroxy compound.

96. The method of claim 95 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

97. The method of claim 87 wherein the anions are derived from pentavalent phosphorous compound.

98. The method of claim 97 wherein said phosphorous compound is phosphate.

99. The method of claim 97 wherein said phosphorous compounds is phosphonate.

100. The method of claim 97 wherein said phosphorous compound is phosphinate.

101. The method of claim 87 wherein the bath also contains a plasticizer.

102. The method of claim 101 wherein the plasticizer is a polyhydroxy compound.

103. The method of claim 101 wherein the plasticizer is a polyalkylene glycol.

104. The method of claim 87 wherein the bath comprises a redox species.

105. The method of claim 104 wherein the redox species is a transition metal complex.

106. The method of claim 87 wherein the anion also is a plasticizer for the polypyrrole or copolymer of pyrrole.

107. A method of preparing electronically conducting polypyrrole or co-polymer of pyrrole which comprises electropolymerization of a pyrrole or a co-polymerizable mixture containing pyrrole at an electronically conductive surface in an electrolytic bath by A. immersing an electronically conductive surface in an electrolytic bath comprising (i) a pyrrole or a mixture of a pyrrole with a co-polymerizable monomer, (ii) one or more low mobility anions which are incorporated into the polypyrrole or co polymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of the polypyrrole or co-polymer of less than 0.1, and (iii) an organic diluent, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing pyrrole at the electronically conductive surface.

108. The method of claim 107 wherein the bath is agitated while the electric current is passed through said bath.

109. The method of claim 107 wherein the polypyrrole or co-polymer of pyrrole is deposited on the conductive surface.

110. The method of claim 107 wherein said transference number is less than O.05.

111. The method of claim 107 wherein the bath also contains a neutral or ionic surface active compound.

112. The method of claim 107 wherein the electrolytic bath is maintained at a temperature of from about 150 to about 500C as the electric current is passed through the bath.

113. The method of claim 107 with the step of heat treating said electronically conducting polypyrrole or co-polymer of pyrrole to enhance the electrochemical storage capacity thereof.

114. The method of claim 107 wherein the anions in the bath are derived from organic sulfates or sulfonates.

115. The method of claim 114 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

116. The method of claim 115 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

117. The method of claim 107 wherein the anion is derived from a sulfated polyhydroxy compound.

118. The method of claim 117 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

119. The method of claim 107 wherein the anions are derived from pentavalent phosphorous compound.

120. The method of claim 119 wherein said phosphorous compound is phosphate.

121. The method of claim 119 wherein said phosphorous compound is phosphonate.

122. The method of claim 119 wherein said phosphorous compound is phosphinate.

123. The method of claim 107 wherein the bath also contains a plasticizer.

124. The method of claim 123 wherein the plasticizer is a polyhydroxy compound.

125. The method of claim 123 wherein the plasticizer is a polyalkylene glycol.

126. The method of claim 107 wherein the bath comprises a redox species.

127. The method of claim 126 wherein the redox species is a transition metal complex.

128. The method of claim 107 wherein the anion also is a plasticizer for the polypyrrole or copolymer of polypyrrole.

129. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising a porous electronically conducting composition comprising an electropolymerized polypyrrole or a co-polymer of pyrrole, said composition characterized by an apparent density of from about 0.01g cm up to about the bulk density of said polypyrrole or copolymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.

130. The cell of claim 129 wherein said polymeric electrode means comprises a porous electronically conducting composite composition comprising at least two members, at least one of which comprises said porous electronically conducting composition.

131. The cell of claim 129 wherein the density of the composition is from about 0.2g cm~3 to about 0.8g cm~3.

132. The cell of claim 129 with said composition also containing at least one low mobility anion characterized by an average ionic transference number for said low mobility anions during reduction of less than about 0.1.

133. The cell of claim 132 wherein said transference number is less than about 0.05.

134. The cell of claim 129 wherein said composition is heat treated to enhance the electrochemical storage capacity of said composition.

135. The cell of claim 132 wherein the anions are derived from organic sulfates or sulfonates.

136. The cell of claim 135 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

137. The cell of claim 132 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

138. The cell of claim 137 wherein the sulfate is lauryl sulfate.

139. The cell of claim 132 wherein the anion is derived from a sulfated polyhydroxy compound.

140. The cell of claim 139 wherein the sulfated polyhyroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

141. The cell of claim 132 wherein the anions are derived from pentavalent phosphorous compound.

142. The cell of claim 141 wherein said phosphorous compound is phosphate.

143. The cell of claim 141 wherein said phosphorous compound is phosphonate.

144. The cell of claim 141 wherein said phosphorous compound is phosphinate.

145. The cell of claim 129 or 132 with said composition also containing at least one plasticizer.

146. The cell of claim 145 wherein the plasticizer is a polyhydroxy compound.

147. The cell of claim 145 wherein the plasticizer is a polyalkylene glycol.

148. The cell of claim 129 or 132 with said composition comprising a redox species.

149. The cell of claim 148 wherein the redox species is a transition metal complex.

1 50. The cell of claim 132 wherein the anion is also a plasticizer for the composition.

1 51. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising an electronically conducting composition comprising electropolymerized polypyrrole or a co-polymer of pyrrole, said composition containing one or more low mobility anions characterized by an average ionic transference number for said low mobility -anions during reduction of less than about 0.1.

1 52. The cell of claim 151 wherein said transference number is less than 0.05.

153. The cell of claim 151 wherein said composition is heat treated to enhance the electrochemical storage capacity of said composition.

1 54. The cell of claim 1 51 wherein the anions are derived from organic sulfates or sulfonates.

155. The cell of claim 154 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

1 56. The cell of claim 151 wherein the anion is an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

157. The cell of claim 156 wherein the alkyl sulfate is lauryl sulfate.

158. The cell of claim 151 wherein the anion is derived from a sulfated polyhydroxy compound.

159. The cell of claim 1 58 where the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

160. The cell of claim 151 wherein the anions are derived from pentavalent phosphorous compound.

161. The cell of claim 160 wherein said phosphorous compound is phosphate.

162. The cell of claim 160 wherein said phosphorous compound is phosphonate.

163. The cell of claim 160 wherein said phosphorous compound is phosphinate.

164. The cell of claim 151 with said composition also containing at least one plasticizer.

165. The cell of claim 164 wherein the plasticizer is a polyhydroxy compound.

166. The cell of claim 164 wherein the plasticizer is a polyalkylene glycol.

167. The cell of claims 151 with said composition comprising a redox species.

1 68. The cell of claim 167 wherein the redox species is a transition metal complex.

1 69. The cell of claim 151 wherein the anion is also a plasticizer for the composition.

170. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising electronically conducting polypyrrole or a co-polymer of pyrrole prepared by a method which comprises electropolymerization of pyrrole or a copolymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath comprising the steps:: A. immersing an electronically conductive surface in an electrolytic bath comprising at least one liquid and at least one non-miscible liquid or gas or finely divided solid particles wherein a pyrrole or co-polymerizable mixture containing a pyrrole is one of the liquids or is dissolved in at least one of the liquids, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing a pyrrole at the electronically conductive surface.

1 71. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising electronically conducting polypyrrole or a co-polymer of pyrrole prepared by a method which comprises electropolymerization of a pyrrole or a copolymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath comprising the steps:: A. immersing an electronically conductive surface in an electrolytic bath comprising at least one liquid and at least one non-miscible liquid or gas wherein the pyrrole or co-polymerizable mixture containing a pyrrole is one of the liquids or is dissolved in at least one of the liquids, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing pyrrole at the electronically conductive surface.

172. The cell of claim 171 wherein the electric current is continuous or varying.

173. The cell of claim 171 wherein the bath is agitated while the electric current is passed through said bath.

1 74. The cell of claim 171 wherein the polypyrrole or co-polymer of a pyrrole is deposited on the conductive surface.

175. The cell of claim 171 wherein the polypyrrole or co-polymer of a pyrrole is formed as a powder at the electronically conducting surface and is dispersed in the bath.

176. The cell of claim 171 wherein the electrolytic bath comprises pyrrole, water, and a water-immiscible organic diluent.

177. The cell of claim 176 wherein the bath also contains an emulsifier.

178. The cell of claim 171 wherein the polypyrrole or co-polymer of a pyrrole is formed as a powder at the conducting surface and the powder is dispersed in the bath.

179. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising electronically conducting polypyrrole or co-polymer of pyrrole prepared by a method which comprises the steps of A. electropolymerizing a pyrrole or a copolymerizable mixture comprising a pyrrole at an electronically conductive surface in an electrolytic bath by

1. immersing an electronically conductive surface in an electrolytic bath which comprises (a) an aqueous dispersion of a pyrrole, or a mixture of said aqueous dispersion and at least one co-polymerizable monomer, or (b) a pyrrole or mixture of a pyrrole and/or at least one co-polymerizable monomer, water and water-immiscible diluent,

2. agitating the bath, and 3. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or a pyrrole mixture and deposit the polymer or co-polymer on the electronically conductive surface, and B. removing said polymer or co-polymer from the conductive surface.

180. The cell of claim 179 wherein the electrolytic bath is maintained at a temperature of from about 150 to 500C as the electric current is passed through the bath.

181. The cell of claim 179 wherein the electric current is a continuous or varying electric current.

182. The cell of claim 179 wherein the electric current is a direct current.

183. The cell of claim 179 wherein the electrolytic bath also contains an emulsifier.

1 84. The cell of claim 179 wherein the electrolytic bath comprises at least about 50% by weight of water.

185. The cell of claim 170 or 179 wherein the electrolytic bath also contains one or more low mobility anions which are incorporated into the polypyrrole or co-polymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of less than 0.1.

186. The cell of claim 185 wherein said transference number is less than 0.05.

187. The cell of any one of claims 170, 171 or 179 wherein said electronically conducting polypyrrole or co-polymer of pyrrole is heat treated to enhance the electrochemical storage capacity thereof.

188. The cell of claim 185 wherein the anions in the bath are derived from organic sulfates or sulfonates.

189. The cell of claim 188 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

190. The cell of claim 185 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

191. The cell of claim 185 wherein the anion is derived from a sulfated polyhydroxy compound.

192. The cell of claim 191 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

193. The cell of claim 185 wherein the anions are derived from pentavalent phosphorous compound.

194. The cell of claim 193 wherein said phosphorous compound is phosphate.

195. The cell of claim 193 wherein said phosphorous compound is phosphonate.

196. The cell of claim 193 wherein said phosphorous compound is phosphinate.

197. The cell of claim 170 or 179 wherein the bath also contains a plasticizer.

198. The cell of claim 197 wherein the plasticizer is a polyhydroxy compound.

1 99. The cell of claim 197 wherein the plasticizer is a polyalkylene glycol.

200. The cell of claim 170 or 179 wherein the bath comprises a redox species.

201. The cell of claim 200 wherein the redox species is a transition metal complex.

202. The cell of claim 170 or 179 wherein the bath also contains a neutral or ionic surface active compound.

203. The cell of claim 184 wherein the anion also is a plasticizer for the polypyrrole or copolymer of pyrrole.

204. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising electronically conducting polypyrrole or a co-polymer of pyrrole prepared by a method which comprises electropolymerization of pyrrole or a copolymerizable mixture containing pyrrole at an electronically conductive surface in an electrolytic bath comprising the steps of A. immersing an electronically conductive surface in an electrolytic bath comprising an aqueous mixture comprising pyrrole or a mixture of pyrrole and a co-polymerizable monomer and water, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing a pyrrole at the electronically conductive surface.

205. The cell of claim 204 wherein the bath is agitated while the electric current is passed through said bath.

206. The cell of claim 204 wherein the polypyrrole or co-polymer of pyrrole is deposited on the electronically conductive surface.

207. The cell of claim 204 wherein the polypyrrole or co-polymer of pyrrole is formed as a powder at the conductive surface and dispersed in the bath.

208. The cell of claim 204 wherein the bath also contains a neutral or ionic surface active compound.

209. The cell of claim 204 wherein the bath also contains an emulsifier.

210. The cell of claim 204 wherein the bath also contains one or more low mobility anions which are incorporated into the polypyrrole or copolymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of less than 0.1.

211. The cell of claim 210 wherein said transference number is less than 0.05.

212. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising electronically conducting polypyrrole or co-polymer of pyrrole prepared by a method which comprises the steps of A. electropolymerizing a pyrrole or a copolymerizable mixture of a pyrrole at an electronically conductive surface in an electrolytic bath by

1. immersing an electronically conductive surface in an electrolytic bath which comprises an aqueous mixture comprising pyrrole or a co-polymerizable mixture of pyrrole, water, and one or more low mobility anions which are incorporated into the polypyrrole by electropolymerization and which anions are characterized by an average ionic transference number for said low mobility anions on reduction of less than 0.1,

213. The cell of claim 212 wherein said transference is less than 0.05.

214. The cell of claim 212 wherein the electrolytic bath is maintained at a temperature of from about 150 to 50 C as the electric current is passed through the bath.

215. The cell of claim 212 wherein the electric current is a direct current.

216. The cell of claim 204 or 212 wherein said electronically conducting polypyrrole or copolymer of pyrrole is heat treated to enhance the electrochemical storage capacity thereof.

217. The cell of claim 212 wherein the anions in the bath are derived from organic sulfates or sulfonates.

218. The cell of claim 217 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

219. The cell of claim 212 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

220. The cell of claim 212 wherein the anion is derived from a sulfated polyhydroxy compound.

221. The cell of claim 220 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

222. The cell of claim 212 wherein the anions are derived from pentavalent phosphorous compound.

223. The cell of claim 222 wherein said phosphorous compound is phosphate.

224. The cell of claim 222 wherein said phosphorous compound is phosphonate.

225. The cell of claim 222 wherein said phosphorous compound is phosphinate.

226. The cell of claim 212 wherein the bath ålso contains a plasticizer.

227. The cell of claim 226 wherein the plasticizer is a polyhydroxy compound.

228. The cell of claim 226 wherein the plasticizer is a polyalkylene glycol.

229. The cell of claim 212 wherein the bath comprises a redox species.

230. The cell of claim 229 wherein the redox species is a transition metal complex.

231. The cell of claim 212 wherein the anion also is a plasticizer for the polypyrrole or copolymer of pyrrole.

232. An electrochemical cell comprising polymeric electrode means, said polymeric electrode means comprising electronically conducting polypyrrole or co-polymer of pyrrole prepared by a method which comprises electropolymerization of a pyrrole or a copolymerizable mixture containing a pyrrole at an electronically conductive surface in an electrolytic bath by A. immersing an electronically conductive surface in an electrolytic bath comprising (i) pyrrole, or a mixture of pyrrole and a co polymerizable monomer, (ii) one or more low mobility anions which are incorporated into the polypyrrole or co polymer of pyrrole and which are characterized by an average ionic transference number for said low mobility anions during reduction of the polypyrrole or co-polymer of less than 0.1, and (iii) an organic diluent, and B. passing an electric current through said bath at a voltage sufficient to electropolymerize the pyrrole or co-polymerizable mixture containing pyrrole at the electronically conductive surface.

233. The cell of claim 232 wherein the bath is agitated while the electric current is passed through said bath.

234. The cell of claim 232 wherein the polypyrrole or co-polymer of pyrrole is deposited on the conductive surface.

235. The cell of claim 232 wherein said transference number is less than 0.05.

236. The cell of claim 232 wherein the bath also contains a neutral or ionic surface active compound.

237. The cell of claim 232 wherein the electrolytic bath is maintained at a temperature of from about 150 to about 500C as the electric current is passed through the bath.

238. The cell of claim 232 wherein said electronically conducting polypyrrole or copolymer of pyrrole is heat treated to enhance the electrochemical storage capacity thereof.

239. The cell of claim 232 wherein the anions in the bath are derived from organic sulfates or sulfonates.

240. The cell of claim 239 wherein the sulfates or sulfonates are alkyl, aryl, arylalkyl, alkaryl or polyolefin sulfates or sulfonates, each containing one or more anionic sites.

241. The cell of claim 240 wherein the anion is derived from an alkyl sulfate containing at least 4 carbon atoms in the alkyl group.

242. The cell of claim 241 wherein the anion is derived from a sulfated polyhydroxy compound.

243. The cell of claim 242 wherein the sulfated polyhydroxy compound is pentaerythrityl tetrasulfate salt or corresponding acid.

244. The composition of claim 232 wherein the anions are derived from pentavalent phosphorous compound.

245. The composition of claim 232 wherein said phosphorus compound is phosphate.

246. The composition of claim 232 wherein said phosphorous compound is phosphonate.

247. The composition of claim 232 wherein said phosphorous compound is phosphinate.

248. The cell of claim 232 wherein the bath also contains a plasticizer.

249. The cell of claim 248 wherein the plasticizer is a polyhydroxy compound.

250. The cell of claim 248 wherein the plasticizer is a polyalkylene glycol.

251. The cell of claim 232 wherein the bath comprises a redox species.

252. The cell of claim 251 wherein the redox species is a transition metal complex.

253. The cell of claim 232 wherein the anion also is a plasticizer for the polypyrrole or copolymer of pyrrole.

254. An electrochemical cell comprising metal negative electrode means, separator means, electrolyte means, and polymeric positive electrode means, said polymeric positive electrode means comprising a porous electronically conducting composition comprising an electropolymerized polypyrrole or co-polymer of a pyrrole, said composition characterized by an apparent density of from about 0.1 g cm~3 up to about the bulk density of said polypyrrole or copolymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.

255. The cell of claim 254 wherein said negative electrode means comprises an alkali metal, an alkaline-earth metal, or an alloy of said alkali metal or alkaline-earth metal.

256. The cell of claim 254 wherein said negative electrode means comprises a material selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, or an alloy thereof.

257. The cell of claim 254 wherein said composition is heat treated to increase its electrochemical storage capacity.

258. The cell of claim 254 wherein said polymeric positive electrode means provides an enhanced resistive barrier to damage to said cell arising from over discharge.

259. The cell of claim 254 wherein said composition is cold pressed to provide said polymeric positive electrode means.

260. The cell of claim 254 wherein said composition includes binder means, said composition being cold pressed to provide said polymeric positive electrode means.

261. The cell of claim 254 wherein electrical contact is made with said polymeric positive electrode means by screen means or grid means positioned between said polymeric positive electrode means and said separator means.

262. The cell of claim 254 wherein said polymeric positive electrode means includes at least one other redox species.

263. An electrochemical cell comprising separator means, electrolyte means, polymeric negative electrode means and another electrode means, said another electrode means being electrochemically more positive than said polymeric negative electrode means, said polymeric negative electrode means comprising a porous electronically conducting composition comprising an electropolymerized polypyrrole or co-polymer of pyrrole, said composition characterized by an apparent density of from about 0.1 g cm~3 up to about the bulk density of said polypyrrole or copolymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.

264. The cell of claim 263 wherein said composition is heat treated to increase its electrochemical storage capacity.

265. The cell of claim 263 wherein said polymeric negative electrode means provides an enhanced resistive barrier to damage to said cell arising from overcharging.

266. The cell of claim 263 wherein said composition is cold pressed to provide said polymeric negative electrode means.

267. The cell of claim 263 wherein said polymeric negative electrode means includes binder means, said composition being cold pressed to provide said polymeric negative electrode means.

268. The cell of claim 263 wherein electrical contact is made with said polymeric negative electrode means by screen means or grid means positioned between said polymeric negative electrode means and said separator means.

269. The cell of claim 263 wherein said polymeric negative electrode means includes at least one other redox species.

270. An electrochemical cell comprising: separator means; electrolyte means; polymeric positive electrode means; and polymeric negative electrode means; said polymeric positive electrode means comprising a first composition; said polymeric negative electrode means comprising a second composition; said first composition and said second composition each comprising a porous electronically conducting material comprising an electropolymerized poly pyrrole or copolymer of a pyrrole, said material characterized by an apparent density of from about 0.1 g cm~3 up to about the bulk density of said polypyrrole or copolymer and a surface area of at least two times the surface area of a smooth film of bulk density of the composition.

271. The cell of claim 270 wherein said first composition and/or said second composition is heat treated to increase its electrochemical storage capacity.

272. The cell of claim 270 wherein said polymeri positive electrode means provides an enhanced resistive barrier to damage to said cell arising 'from over discharge, and/or said polymeric negative electrode means provides an enhanced resistive barrier to damage to said cell arising from overcharging.

273. The cell of claim 270 wherein said first composition is cold pressed to provide said polymeric positive electrode means and/or said second composition is cold pressed to provide said polymeric negative electrode means.

274. The cell of claim 270 wherein said first composition includes binder means, said first composition being cold pressed to provide said polymeric positive electrode means; and/or said second composition includes binder means, said second composition being cold pressed to provide said polymeric negative electrode means.

275. The cell of claim 270 wherein electrical contact is made with said polymeric positive electrode means by screen means or grid means positioned between said polymeric positive electrode means and said separator means; and/or wherein electrical contact is made with said polymeric negative electrode means by screen means or grid means positioned between said polymeric negative electrode means and said separator means.

276. The cell of claim 270 wherein said polymeric positive electrode means and/or said polymeric negative electrode means includes at least one other redox species.

277. An electrochemical cell comprising metal negative electrode means, separator means, electrolyte means, and polymeric positive electrode means, said polymeric positive electrode means comprising a composition comprising electropolymerized polypyrrole or a copolymer of pyrrole, said composition containing one or more low mobility anions characterized by an average ionic transference number for said low mobility anions during reduction of less than about 0.1.

278. The cell of claim 277 wherein said transference number is less than about 0.01.

279. The cell of claim 277 wherein said negative electrode means comprises an alkali metal, an alkaline-earth metal, or an alloy of said alkali metal or alkaline-earth metal.

280. The cell of claim 277 wherein said negative electrode means comprises a material selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, or an alloy thereof.

281. The cell of claim 277 wherein said composition is heat treated to increase its electrochemical storage capacity.

282. The cell of claim 277 wherein said polymeric positive electrode means provides an enhanced resistive barrier to damage to said cell arising from over discharge.

283. The cell of claim 277 wherein said composition is cold pressed to provide said polymeric positive electrode means.

284. The cell of claim 277 wherein said composition includes binder means, said composition being cold pressed to provide said polymeric positive electrode means.

285. The cell of claim 277 wherein electrical contact is made with said polymeric positive electrode means by screen means or grid means positioned between said polymeric positive electrode means and said separator means.

286. The cell of claim 277 wherein said polymeric positive electrode means includes at least one other redox species.

287. An electrochemical cell comprising separator means, electrolyte means, polymeric negative electrode means, and another electrode means, said another electrode means being more electrochemically positive than said polymeric negative electrode means, said polymeric negative electrode means comprising a composition comprising electropolymerized polypyrrole or a copolymer of pyrrole, said composition containing one or more low mobility anions characterized by an average ionic transference number for said low mobility anions during reduction of less than about 0.1.

288. The cell of claim 287 wherein said transference number is less than about 0.01.

289. The cell of claim 287 wherein said composition is heat treated to increase its electrochemical storage capacity.

290. The cell of claim 287 wherein said polymeric negative electrode means provides an enhanced resistive barrier to damage to said cell arising from overcharging.

291. The cell of claim 287 wherein said composition is cold pressed to provide said polymeric negative electrode means.

292. The cell of claim 287 wherein said composition includes binder means, said composition being cold pressed to provide said polymeric negative electrode means.

293. The cell of claim 287 wherein electrical contact is made with said polymeric negative electrode means by screen means or grid means positioned between said polymeric negative electrode means and said separator means.

294. The cell of claim 287 wherein said polymeric negative electrode means includes at least one other redox species.

295. An electrochemical cell comprising: separator means; electrolyte means; polymeric positive electrode means; and polymeric negative electrode means; said polymeric positive electrode means comprising a first composition; said polymeric negative electrode means comprising a second composition; said first composition and said second composition each comprising electropolymerized polypyrrole or copolymer of pyrrole containing one or more low mobility anions characterized by an average ionic transference number for said low mobility anions during reduction of less than about 0.1.

296. The cell of claim 295 wherein said transference number is less than about 0.01.

297. The cell of claim 295 wherein said first composition and/or said second composition is heat treated to increase its electrochemical storage capacity.

298. The cell of claim 295 wherein said polymeric positive electrode means provides an enhanced resistive barrier to damage to said cell arising from over discharge, and/or said polymeric negative electrode means provides an enhanced resistive barrier to damage to said cell arising from overcharging.

299. The cell of claim 295 wherein said first composition is cold pressed to provide said polymeric positive electrode means and/or said second composition is cold pressed to provide said polymeric negative electrode means.

300. The cell of claim 295 wherein said first composition includes binder means, said first composition being cold pressed to provide said polymeric positive electrode means; and/or wherein said second composition includes binder means, said second composition being cold pressed to provide said polymeric negative electrode means.

301. The cell of claim 295 wherein electrical contact is made with said polymeric positive electrode means by screen means or grid means positioned between said polymeric positive electrode means and said separator means; and/or wherein electrical contact is made with said polymeric negative electrode means by screen means or grid means positioned between said polymeric negative electrode means and said separator means.

302. The cell of claim 295 wherein said polymeric positive electrode means and/or said polymeric negative electrode means includes at least one other redox species.

303. The cell of any one of claims 129, 1 52, 170, 179, 204, 212 or 232 wherein said polymeric electrode means comprises polymeric positive electrode means.

304. The cell of any one of claims 129, 152, 170 179,204,212 or 232 wherein said polymeric electrode means comprises polymeric negative electrode means.

305. The cell of any one of claims 129, 152, 170, 1 79, 204, 212 or 232 wherein said polymeric electrode means comprises polymeric positive electrode means and polymeric negative electrode means.

306. A primary battery comprising polymeric electrode means, said electrode means comprising the composition of claim 1 or 25.

307. A secondary battery comprising polymeric electrode means, said electrode means comprising the composition of claim 1 or 25.

308. A primary battery comprising polymeric electrode means, said electrode means comprising the product of the method of any one of claims 45, 46, 54, 79, 87 or 107.

309. A secondary battery comprising polymeric electrode means, said electrode means comprising the product of the method of any one of claims 45, 46, 54, 79, 87 or 107.

310. The invention in its several novel aspects.