FR2460044A1 - Non aqueous battery resistant to anode passivation - by treating separator with vinyl! polymer, esp. PVC or vinyl! chloride-vinyl! acetate copolymer - Google Patents

Abstract

A non-aq. battery comprises an ionically conductive electrolyte-cathode soln. comprising a solute dissolved in an active liquid cathode; an active metal anode; a cathodic collector; a separator between the anode and the cathodic collector and a coating of a vinyl polymer on at least part of the separator surfaces. Passivation of the anode during storage and operation of the battery is prevented.

Description

 The present invention relates to a non-aqueous cell comprising an active metal anode, a cathode collector, a separator disposed between the cathode collector and the anode and separating them from each other} and an active liquid electrolyte-cathode, the surface of the separator facing the anode being coated with a film of vinyl polymer.

 The production of high energy batteries requires, among other things, the compatibility of an electrolyte endowed with advantageous electrochemical properties with very reactive anodic materials such as lithium or a similar material. The use of aqueous electrolytes is excluded from these systems because the anode materials are sufficiently active to react chemically with water. It has therefore been necessary, in order to achieve the high energy density that can result from the use of these highly reactive anodes, to direct research towards non-aqueous electrolytic systems.

The term "non-aqueous electrolyte" as used herein means an electrolyte which is composed of a solute such as, for example, a metal salt or a complex salt of elements of Group IA, IIA, IIIA or IVA of
Periodic table, in solution in a suitable nonaqueous solvent. The term "Periodic Table" as used herein means the Periodic Table of the Elements reproduced on the third cover of the book "Handbook of Chemistry and Physics", 48th Edition,
The Chemical Rubber Co., Cleveland, Ohio, 1967-1968.

 A multitude of solutes are known and the use of many of them has been suggested, but the choice of a suitable solvent has been particularly problematic. The ideal electrolyte for a battery should be a solvent-solute pair with a wide range of existence in the liquid state, high ionic conductivity, and high stability. A wide range of existence in the liquid state, ie, high boiling point and low freezing point, is essential if the battery is to operate at temperatures other than normal ambient temperatures. High ionic conductivity is required if the battery is to be capable of high flow.

Stability is required for the materials constituting the electrodes, the battery materials and the reaction products of the battery so that the shelf life is long when the battery is used in a primary or secondary battery.

The literature has recently made known that certain materials are capable of behaving both as an electrolyte carrier, i.e. as a solvent for the salt used as an electrolyte, and as an active cathode for a non-electrochemical cell. aqueous. Patents
No. 3,475,226, US Pat. No. 3,567,515 and US Pat. No. 3,578,500 each disclose that liquid sulfur dioxide or solutions of sulfur dioxide and a cosolvent assume this dual function in non-aqueous electrochemical cells. . Although these solutions assume their dual function, they are not without several disadvantages in service. Sulfur dioxide is always present and) expected that it is a gas at ordinary temperatures, this substance must be contained in the stack in the form of a liquid under pressure or in solution in a liquid solvent. Handling and packaging problems are caused if sulfur dioxide is used alone, and an additional component and an additional mounting step are required if the sulfur dioxide is to be dissolved in a liquid solvent. As noted above, a broad range of existence in the liquid state encompassing normal ambient temperatures is a desirable feature for an electrolyte solvent. Obviously, sulfur dioxide is not satisfactory from this point of view at atmospheric pressure.

U.S. Patent Application No. 439,521, filed February 4, 1974 to GE Blomgren et al., Discloses a non-aqueous electrochemical cell comprising an anode, a cathode collector and an electrolyte-cathode, the latter consisting of a solution of a solute endowed with ionic conductivity in an active cathode (depolarizer), the latter consisting of a liquid oxyhalide of a Group V or Group VI element
Periodic Table. Although oxyhalides can be used effectively as a component of an electrolytecathode together with an active metal anode, for example a lithium anode, to make a battery advantageously having a high energy density, it has been observed that if the battery is maintained for a prolonged period of about three days or more, anode passivation occurs which results in undesirable voltage response delays at the beginning of the discharge along with high internal resistance batteries.

 U.S. Patent No. 3,993,501 discloses a means for minimizing or preventing undesirable voltage response delays at the start of discharging non-aqueous cells, using an oxyhalide-containing electrolyte-cathode, by applying a film of a vinyl polymer to the surface of the anode which contacts the electrolyte cathode.

U.S. Patent Application No. 015,938 discloses a non-aqueous cell comprising an anode of active metal, for example lithium, a liquid electrolytecathode comprising a solute dissolved in a solvent which is an oxyhalide of an element. Group V or
Group VI of the Periodic Table of the Elements, elemental sulfur or a sulfur compound being incorporated in the electrolyte-cathode so as to substantially eliminate the initial voltage response time of the cell during the discharge.

 It is an object of the present invention to substantially prevent passivation of the active metal anode into the electrolyte-liquid cathode cells.

 Another object of the present invention is to find a liquid electrolyte-cathode battery in which the surface of the anode-facing separator is coated with a vinyl polymer film so as to substantially avoid the passivation of the metal anode. active during storage and use of the battery.

 Another object of the invention is to find an electrolyte-cathode cell formed of an oxyhalide in which the surface of the separator facing the active metal anode carries a thin adhering film of a vinyl polymer and elemental sulfur or a sulfur compound is used in the cathode electrolyte in the manner taught in the aforementioned US patent application 015938, in order to effectively prevent passivation of the active metal anode during storage and use of the battery.

 Other features and advantages of the present invention will become apparent from the detailed description which follows.

 The invention relates to a non-aqueous high energy density cell comprising an active metal anode; a cathodic collector; a separator disposed between the anode and the cathode collector; a solution of an electrolyte-cathode endowed with ionic conductivity comprising a solute dissolved in an active liquid cathode (depolarizing) with or without a reactive or non-reactive co-solvent; at least a portion of the surface of the separator, preferably that facing the anode, being coated with a vinyl polymer film so as to reduce the duration of the initial voltage response time of the battery during discharge. Preferably, the vinyl coating carried by the separator should be used in an amount within the range of about 0.7 to about 3.5 g / m of the projected air, particularly in the range of about 1.5 to about 1.8 g / m. It is considered that less than about 0.7 g / m 2 is unable to significantly reduce the duration of the voltage response time at the initial discharge while an amount greater than about 3.5 g / m would result in cracking. separator and interfere with the flow of the electrolyte.

 The term "vinyl polymer" as used herein includes polymers in which the monomeric units are similar to each other (i.e., homopolymers) or differ from each other (i.e., copolymers). .

As used herein and as described in an article by Akiya Rozawa and RA Powers titled "Electrochemical Reactions In Batteries" published in the "Journal of
Chemical Education, Vol 49, pp 287-291, September 1972 issue, a cathodic depolarizer is the reaction body of the cathode and, therefore, it is the material that is electrochemically reduced at the cathode. is not an active reducible material and behaves both as a current collector and as an electronic conductor towards the positive (cathode) terminal of a cell.In other words, the cathodic collector is a site for the Electrochemical reduction reaction of the active cathode material and the electronic conductor towards the cathode terminal of a battery.

 An active liquid-reducible cathodic material (depolarizer) may be mixed with a conductive solute which is a non-reactive material but is added to improve the conductivity of liquid active reducible cathodic materials, or may be mixed with a solute conductor and a reactive or non-reactive co-solvent.

A reactive co-solvent is a co-solvent which is endowed with electrochemical activity and which therefore behaves as an active cathodic material while a non-reactive co-solvent is a solvent which is devoid of electrochemical activity and which, therefore, can not behave as an active cathodic material.

 The separator for use in accordance with the invention must be chemically inert and insoluble in the electrolyte-liquid cathode and must be porous so as to allow the liquid electrolyte to infiltrate and come into contact with the liquid electrolyte. with the anode of the cell, so as to establish a way of ion transfer between the anode and the cathode. An advantageous separator to be used in accordance with the invention is a mat of non-woven or woven glass fibers.

 Any compatible solid material that is substantially electrically conductive may be used as a cathode collector in the cells of the present invention.

 It is desirable that there is as much surface contact as possible between the catholyte electrolyte and the collector. It is therefore preferred to use a porous collector, since it has a high surface area interface with the electrolyte-liquid cathode. The collector may be metallic and may be present in any physical form, for example in the form of a film, canvas or compressed metal powder.

However, preferably, a compressed powder manifold must be at least partially formed of a carbonaceous material or other material with a large specific surface area.

 The solute can be a single salt or a double salt which gives a solution endowed with ionic conductivity when it is dissolved in the solvent. Preferred solutes are inorganic or organic Lewis acid complexes and inorganic ionizable salts. The main conditions to be satisfied involve that the salt, whether simple or complex, is compatible with the solvent that is used and that it gives a solution that is endowed with ionic conductivity. In accordance with the Lewis concept or the electronic concept of-acids and bases, many substances that do not carry active hydrogen can behave as acids or as electron-doublet acceptors. The basic concept is stated in the chemical literature (Journal of the Franklin Institute, Volume 226 July / December 1938, pp. 293-313, G. N. Lewis).

 A suggested reaction mechanism concerning the mode of operation of these complexes in a solvent is described in detail in US Pat. No. 3,542,602 in which the hypothesis is that the complex salt or double salt formed between the Lewis acid and the ionizable salt constitutes an entity that is more stable than any of the components considered alone.

 Examples of advantageous Lewis acids for use in the present invention include aluminum fluoride, aluminum bromide, aluminum chloride, antimony pentachloride, zirconium tetrachloride, phosphorus pentafluoride, boron fluoride, boron chloride and boron bromide.

 Preferred ionizable salts for use in conjunction with Lewis acids include lithium fluoride, lithium chloride, lithium bromide, lithium sulfide, sodium fluoride, sodium chloride, sodium bromide, fluoride of potassium, potassium chloride and potassium bromide.

 It will be apparent to those skilled in the art that the Lewis acid double salts and an ionizable inorganic salt may be used as is or that the individual components may be added to the solvent separately to form the salt or salts in situ. resulting ions. A double salt of this kind, for example, is one that is formed by the combination of aluminum chloride and lithium chloride which gives lithium aluminum tetrachloride.

The present invention provides a non-aqueous electrochemical system comprising an active metal anode, a cathode collector, a separator disposed between the anode and the cathode collector and carrying on its anode-facing surface a vinyl polymer film, and a electrolyte-cathode, the latter comprising a solute dissolved in an active reducible electrolytic solvent formed of at least one oxyhalide of a Group V element or of Group VI of the
Periodic table and / or a halide of an element of the
Group IV, V or VI of the Periodic Table, in the presence or absence of a co-solvent. The solvent of the active reducible electrolyte assumes the dual function of behaving as a solvent for the electrolytic salt and as an active cathode for the cell. The term "electrolyte-cathode" is used herein to refer to electrolytes comprising solvents that can assume this dual function.

 The use of a single cell component as both an electrolytic solvent and as an active cathode is a relatively recent advance since, previously, it was generally considered that the two functions were necessarily independent and could not be assumed by the same. material. For an electrolytic solvent to operate in a cell, it is necessary that it be in contact with both the anode and the cathode so as to form a continuous ion path between them. Therefore, it has been generally accepted that the active cathode material should never be in direct contact with the anode and thus it has become apparent that the two functions are mutually exclusive.

However, it has recently been discovered that certain active cathode materials such as liquid oxyhalides do not chemically react appreciably with the active anode metal at the interface between the metal and the cathode material, thereby allowing the latter to come into direct contact with the anode and behave as the support for the electrolyte. Although the theory on which the cause of the inhibition of the direct chemical reaction is based is not fully understood at this point in time and there is no desire in fact to be attached to any theory with regard to the present invention. it appears that a direct chemical reaction is inhibited either by a naturally high activation energy of the reaction, or by the formation of a thin protective film on the surface of the anode. Any protective film on the surface the anode should not be formed to an extent excessive enough to result in a large increase in anodic polarization.

 Although active reducible liquid cathodes such as oxyhalides inhibit the direct reaction of the active metal anode surfaces in. sufficient for them to behave both as a cathode material and as an electrolyte carrier for non-aqueous cells, they actually cause the formation of a surface film on the active metal anode during storage of the cell, in particular at high pressures, this film being formed of a rather dense layer of crystalline material. This crystalline layer obviously causes passivation of the anode and results in a voltage response delay during the initial discharge together with high values of internal battery resistance in the range of 11 to 15 ohms for a normal battery. type C.

 The degree of anodic passivation can be measured by observing the time required for the closed circuit voltage of the stored battery to reach its desired voltage level when the discharge has begun. If this response time exceeds 20 seconds, anodic passivation should be considered excessive for most applications. It has been observed for example in lithium oxyhalide batteries that after a voltage has been applied across the battery, the battery voltage decreases immediately below the desired level of discharge and then a speed which depends on the temperature, the thickness of the crystalline layer and the electrical voltage.

 The exact composition of this layer is not known The thickness and density of the crystalline layer as well as the size and shape of the crystals vary, as we have seen, with the length of the storage period as well as with temperature during storage; for example, at low temperatures, relatively little growth of the crystalline layer is observed compared to the higher growth of the layer at high temperatures of about 700C. It has also been observed that when the oxyhalides such as thionyl chloride or sulphuryl chloride are saturated with sulfur dioxide and then placed in a lithium anode cell, a crystalline layer is rapidly formed on the surface of the lithium while passivating. metal.

( désigne un radical libre).In accordance with the present invention, it has been found that anodic passivation can be substantially prevented by the presence of a layer of vinyl polymer film adhered to at least a portion of the surface of the battery separator which is preferably turned towards the anode. The vinyl polymer film should adhere to the separator, remain stable in the liquid electrolytic liquid, and not significantly reduce the battery capacity during storage and discharge. In most cases, the presence of the polymer film can even increase the capacity of the battery during a high flow charge. Although it is not desired to limit the invention to any theory, it appears that the one of the reasons why vinyl polymers such as vinyl chloride polymers are stable in the oxyhalide electrolytecathode cell, for example a lithium oxyhalide battery, can be explained as follows: one of the accepted mechanisms of degradation of a vinyl chloride polymer is dehydrochlorination, i.e. the cleavage of a chlorine atom and a hydrogen atom to form a molecule of HCl. This process continues until the electronegativity of the remaining chlorine atoms of the polymer is compensated for by the conjugation energy (i.e., the formation of double bonds) of the polymer. It is assumed that subsequent degradation has occurred. place according to a mechanism of free radical production, as indicated below:

(denotes a free radical).

Most of the compounds that have shown themselves capable of interaction or interference with polymer degradation can be exemplified by the formation of radicals of the R-, RO-, ROO- and atomic-chlorine types. The reaction mechanism by which SO2Cl2 is decomposed presumably proceeds by formation of free radicals, ie Cl and sO 2 Cl radicals as described in an article by ZG Szabo and T. Bérces, entitled The Mechanism of the
Thermal Decomposition of Sulfuryl Chloride ", Zeit.
Physikalische Chemie, new series 12: 168-195 (1952).

Thus, according to the LeChatelier principle (chemical equilibrium), the stability of vinyl chloride polymers can be promoted in a medium such as that which prevails in systems based on an oxyhalide. In other words, if the concentration of any of the degradation products is high, the reaction equilibrium shifts in favor of the undegraded initial polymer.

The unsaturated polymeric materials which are suitable for the coating of separators according to the invention can be represented by the following general formula representing the monomeric unit of the polymer:
tCH2 = CRxRy) in this formula, Rx and Ry of a monomeric unit have the same values as in the other monomeric units (homopolymers) or else Rx or Ry of the monomeric unit of a polymer does not have the same value as in the monomeric unit of the second polymer (copolymers) and
Rx is chosen from hydrogen, halogens such
as chlorine and bromine, and alkoxy groups
whose alkyl radicals have 1 to 5 carbon atoms
bone (eg acetoxy); and
R is selected from halogens such as chlorine
and bromine and alkoxy groups containing
alkyl radicals having 1 to 5 carbon atoms
(for example acetoxy).

de chlorure de vinyle, dont le motif monomérique est
tCH2 = CH-Cl) et de chlorure de vinylidène dont le motif monomérique est

Examples of suitable polymers include vinyl acetate polymers in which the monomeric unit has the formula

of vinyl chloride, the monomeric unit of which is
tCH2 = CH-Cl) and vinylidene chloride whose monomeric unit is

 By way of example, mention is made of a copolymer of vinyl chloride and of vinyl acetate in which Rx is a hydrogen atom in the monomeric unit of the two polymers and R in the monomeric unit of a polymer is a chlorine atom. and, in the monomeric unit of the second polymer, represents an acetoxy group.

 Polymers for use in the present invention must not be degraded or decomposed in the presence of the solvent used for the coating process or the liquid electrolyte-cathode used in the cell, they must also be capable of forming a thin coating which can adhere to the separator.

 Although not all the materials of the above-defined group have the characteristics set forth above, any person skilled in the art can readily choose the appropriate ones by simply experimenting the material in the form of a coating applied to the material. the surface of a separator, which is immersed in a liquid electrolyte-cathode. For example, polyethylene and polypropylene would not be suitable because they would decompose in a liquid oxyhalide.

 Vinyl polymers that can be advantageously used in the present invention can be selected from copolymers of vinyl chloride and vinyl acetate containing, for example, 86% vinyl chloride and 14% vinyl acetate. copolymers containing 86% vinyl chloride, 13% vinyl acetate and 1% of an interpolymerized dibasic acid (0.7-0.8 carboxyl group), homopolymers of vinyl chloride and homopolymers of vinyl.

 The vinyl polymer film can be applied to the surface of the separator by any conventional technique, for example by spraying, brushing or the like in the presence or absence of a suitable liquid suspending medium. for example 3-pentanone, methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK) and 2-pentanone. A suitable liquid suspending medium could be formed by the oxyhalides used as solvents in the cell, for example thionyl chloride (SOCl 2) or sulphuryl chloride (SO 2 Cl 2). Thus, a vinyl polymer such as a copolymer of Vinyl chloride and vinyl acetate (86% vinyl chloride and 14% vinyl acetate with a molecular weight of approximately 40,000) can be dissolved in thionyl chloride and the solution can then be applied to the surface of the separator either by immersion of the latter in the solution, or by application of the solution with a brush or by spraying on the surface of the separator.

Upon evaporation of the oxyhalide solvent, a thin adhering film remains on the surface of the separator. For example, the separator could be easily dip coated in a 1% vinyl solution of vinyl acetate-vinyl chloride copolymer in 3-pentanone and then drying the separator for one minute at about 2000C. This would not only have the effect of depositing an advantageous layer of vinyl polymer on the surface of the separator, but would also improve the mechanical handling characteristics of the material constituting the separator. If desired, a thin layer of a vinyl polymer film could be applied to the separator provided that intimate contact and good adhesion to the separator can be achieved.

 In the industrial production of batteries, it is much easier to coat the surface of the separator than to coat the anode and, therefore, the mechanical handling characteristics of the separator are improved thereby facilitating its incorporation into the cell.

 The concentration of the vinyl polymer in the liquid medium can vary within wide limits as long as the amount of vinyl polymer is deposited on the separator as specified above. When using a separator having a porosity of about 50%, it has been observed that a suitable vinyl polymer concentration is between about 0.5 and 3.0% by weight based on the weight of the liquid medium. suspending. A concentration of less than 0.5% by weight would probably be insufficient to obtain an effective film on the separator, whereas a concentration greater than 3.0% by weight would not offer any appreciable additional protection against the passivation of the metal anode and could even lead to deterioration of the separator during handling.

 The effective range of vinyl polymer concentration may range from about 0.7 to about 3.5 g / m 2 of apparent surface area and preferably from about 1.5 to about 1.8 g / m 2. A concentration of less than about 0.7 g / m 2 would not be able to significantly prevent the passivation of the active metal anode, for example lithium, while a concentration greater than about 3.5 g / m 2 would result in elevation undesirable of the internal resistance of the battery.

 Preferred oxyhalides for use according to the invention include sulfuryl chloride, thionyl chloride, phosphorus oxychloride, thionyl bromide, chromyl chloride, vanadyl tribromide and selenium oxychloride.

Advantageous organic co-solvents for use in the present invention include the following classes of trialkyl borate compounds: for example trimethyl borate
(CH30) 3B (liquid range -29.3 to 670C) - tetralkyl silicates: for example tetra silicate
methyl (CH 3 O) 4 Si (boiling point 1210 C) - nitroalkanes: for example nitromethane CH 3 NO 2 (range
liquid -17 to 100.80C) - alkylnitriles: for example acetonitrile CH3CN (range
liquid -45 to 81.60C) - dialkylamides: for example dimethylformamide, HCON (CH3) 2
(liquid range -60.48 to 1490C) - lactams: for example N-methylpyrrolidone,

<tb> CH2-CH2-CE2CO <SEP> * <SEP> CS3 <SEP>
<tb> (liquid range -16 to 2020C) - tetraalkylureas: for example tetramethylurea,
(CH3) 2N-CO-N (CH3) 2 (liquid range -1.2 to 1660C) - esters of monocarboxylic acids: for example acetate
ethyl (liquid range -83.6 to 77.060C) - ortho esters: eg trimethyl orthoformate
HC (OCH3) 3 (boiling point 1030C) - lactones: for example gamma-butyrolactone
(liquid range -42 to 2060C)

<tb> CH2-CH2-CH2-o-CO <SEP>
<tb> - monoethers: for example diethyl ether (liquid range
-116 to 34.50C) - polyethers: for example 1,1- and 1,2-dimethoxyethane
(respective liquid ranges -113.2 to 64.50C and -58 to
830C) - cyclic ethers: for example tetrahydrofuran (range
liquid -65 to 670C); 1,3-dioxolane (liquid range -95 to
780C) - nitroaromatic compounds: for example nitrobenzene
(liquid range 5.7 at 210.80 ° C) - aromatic carboxylic acid halides: by
benzoyl chloride example (liquid range 0 to 1970C);
benzoyl bromide (liquid range -24 to 2180C) - aromatic sulfonic acid halides: for example
benzenesulfonyl chloride (liquid range 14.5 to 10C) - aromatic phosphonic acid dihalides: by
benzenephosphonyl dichloride (boiling point
258 C) - dialkyl carbonates: for example dimethyl carbonate
thyle OC (OCH3) 2 (liquid range 2 to 900 ° C) - alkylene carbonates: for example propylene carbonate

<tb> CH (CH3) CH2-O-CO-O
<tb> (liquid range -48 to 2420C) - aromatic thiophosphonic acid halides
for example benzenethiophosphonyl dichloride
boiling point 1240 ° C. under a vacuum of 5 mm) - cyclic sulphones: for example sulpholane

<tb> CH2-CH2-CH2-CH2 <SEP> 2 <SEP>
<tb> (melting point 220C); 3-methyl
sulfolane (melting point -10C) alkylsulfonic acid halides: for example chlo
methanesulfonyl chloride (boiling point 1610C) alkylcarboxylic acid halides: for example
acetyl chloride (liquid range -112 at 50.90C); bromide
acetyl (liquid range -96 to 760C); propio chloride
nyle (liquid range -94 to 800C) saturated heterocyclic compounds: for example tetra
hydrothiophene (liquid range -96 to 1210C); 3-methyl-2
oxazolidone (melting point 15 ° -90 ° C.) - dialkylsulfamic acid halides: for example
dimethylsulfamyl chloride (boiling point 800C,
16 mm) - alkyl halogenosulphonates: for example chlorosulphonate
ethyl (boiling point 7510C) halogenated heterocyclic carboxylic acid halides
for example 2-furoyl chloride (liquid range
to 1730C) pentagonal unsaturated heterocyclic compounds: by
example 3,5-dimethylisoxazole (boiling point
1400C); 1-methylpyrrole (boiling point 1140C)
2,4-dimethylthiazole (boiling point 1440C); furan
(liquid range -85.65 to 31.360C) esters and / or halides of dicarboxylic acids: by
example ethyl chloride and oxalyl (boiling point
1350C) halides of alkylsulfonic acids and halides
mixed carboxylic acids: for example
chlorosulfonyl and acetyl (boiling point 980C
under a vacuum of 10 mm) - dialkylsulfoxides: for example dimethylsulfoxide (range
liquid 18.4 to 1890C) dialkyl sulphates: for example dimethyl sulphate
(liquid range -31.75 to 188.50C) - dialkyl sulfites: eg dimethyl sulfite
(boiling point 126 C) - alkylene sulfites: eg ethylene sulfite
glycol (liquid range -11 to 1730C) - halogenated alkanes: for example methylene chloride (liquid range -95 to 40 ° C) 1.3 d ic; 1,3-dichloropropane (range
liquid -99.5 to 120.4 C).

 Among the co-solvents indicated above, those which are preferred are nitrobenzene; tetrahydrofuran; 1,3-dioxolane; 3-methyl-2-oxazolidone; propylene carbonate; gamma-butyrolactone; sulfolane; ethylene glycol sulfite; Dimethyl sulphite and benzoyl chloride Among the preferred co-solvents, the best are nitrobenzene, 3-methyl-2-oxazolidone, benzoyl chloride, dimethyl sulphite and ethylene glycol sulphite, because they have a greater chemical inertness with respect to the components of the cell and because they have wide liquid ranges and, in particular, because they allow a very efficient use of cathode materials.

In accordance with the invention, it is also possible to use inorganic solvents such as liquid inorganic halides of Group IV, V and VI elements of
Periodic table, for example selenium tetrafluoride (SeF4), selenium monobromide (Se2Br2), thiophosphoryl chloride (PSC13), thiophosphoryl bromide (PSBr3), vanadium pentafluoride (VF5), lead tetrachloride ( PbCl4), titanium tetrachloride (TiCl4), sulfur decafluoride (S2F10), tin bromide-trichloride (SnBrCl3), dibromide-tin dichloride (SnBr2Cl2), tribromide-tin chloride (SnBr3Cl) ), the sulfur monochloride (82Cl2) and the sulfur dichloride (SCl2). These halides, in addition to behaving as a solvent for the electrolyte in non-aqueous cells, can also play the role of a active reducible cathode thus contributing to the total active reducible material in these cells.

 Useful anode materials are generally consumable metals and include aluminum, alkali metals, alkaline earth metals and alloys of alkali metals or alkaline earth metals with each other and with other metals. The term "alloy" as used herein includes mixtures, solid solutions such as lithium-magnesium, and intermetallic compounds such as lithium mono-aluminide. Preferred anode materials are alkali metals such as lithium, sodium and potassium, and alkaline earth metals such as calcium.

 In the preferred embodiment, the choice of the particular oxy-halide for a particular cell according to the invention should also be considered in relation to the stability of the oxy-halide in question in the presence of the other components of the cell. and the temperatures at which the battery must operate. Therefore, one must choose an oxyhalide that is stable in the presence of the other components of the stack.

 In addition, if it is desired to make the electrolyte solution more viscous or to transform it into a gel, a gelling agent such as colloidal silica may be added.

 The present invention is illustrated by the following examples, given without limitation.

EXAMPLE 1
Three batches of 12mm diameter stacks are prepared using the following components:
0.45 g of lithium;
a cathode collector made from 0.65 g of a mixture of 90% by weight of carbon black and 10% by weight of "Teflon" binder (trade mark designating a polytetrafluoroethylene)
a felted nonwoven fiberglass separator (type 9348 ", from Mead Co.) in contact with the cathode collector, and
2.4 cc of a 1M LiAlC14 electrolyte-liquid cathode solution in SOCl2, containing added lithium sulfide to its saturation point in the solution.

 The components are assembled in stainless steel containers which are closed with lids in a conventional manner.

 The above batteries are kept in various conditions and then discharged across a 75 ohm resistor. The average discharge voltage after one second for three cells of each batch is shown in the following Table I.

TABLE I
Storage conditions
Batch of 1 week 1 month to 3 months with fresh batteries at 710 200C 200C
1 3,18V 2,50V 1,76V 1,38V
2 3,40V 1,08V 1,82V 0,96V 2,88V 1,27V 1,52V 1,07V
Three other batches of batteries were prepared in the manner indicated above except that the separators, before being put into place in the cells, were immersed in a 1% by weight solution of acetate copolymer. vinyl and vinyl chloride in 3-pentanone and then dried quickly by heating at about 2000C for one minute. The copolymer of vinyl acetate and vinyl chloride is the commercial product "VYHH" of the firm Union
Carbide Corporation, containing 86% by weight of vinyl chloride and 14% by weight of vinyl acetate. The separators bearing the vinyl polymer coating are easier to handle mechanically and incorporate into the piles. The three batches of batteries were kept under various conditions and the batteries were discharged across a 75 ohm resistor. The average voltage observed for three cells of each batch after one second is shown in Table II.

TABLE II
Storage conditions
Batch of 1 week 1 month to 3 months fresh batteries at 710C 200C 200C
4 3,21V 1,50V 2,18V 1,53V
5 3.39V 1.50V 2.00V 1.87V
6 3.01V 1.25V 1.96V 1.72V
As these results indicate, batteries with vinyl polymer-coated separators have a higher average voltage value measured after storage for 1 month and for 3 months than cells with uncoated separators.

 The batteries of the six batches were then continuously discharged across a 75-ohm resistor after storage under varying conditions and the average amp-hour (Ah) numbers calculated for three cells in each batch are shown in the table. III.

TABLE III
Storage conditions
1 week 1 month to 3 months battery pack at 710C 200C 200C
1 0.48Ah 0.57Ah 0.51Ah
2 0.49Ah 0.65Ah 0.56Ah
3 0.52Ah 0.57Ah 0.59Ah
4 0.62Ah 0.63Ah 0.63Ah
0.55Ah 0.57Ah 0.63Ah
6 0.72Ah 0.59Ah 0.61Ah
EXAMPLE 2
Several other cells were made in the same manner as in Example 1 except that the solution used to coat the separators was a solution ranging from 0.5 to 3% by weight of vinyl acetate copolymer and chloride vinyl ("VYHH") in 3-pentanone as shown in Table IV. Three batteries of each type, including three batteries whose separator had not been coated, were stored under various conditions and then discharged across a 75 ohm resistor. The average voltage after one second and the average number delivered Ampere-hours are shown in the following Table IV.

TABLE IV Conditions No "VYHH" 0.5% of 1% of 1.5% of 2% of 3% of storage (control stack) "VYHH""VYHH""VYHH""VYHH""VYHH" at charge 3,18V 3,20V 3,17V 3,19V 3,43V 3,44V 1 week at 71 C 2,50V 1,98V 2,17V 2,33V 1,65V 1,83V
0.48Ah 0.42Ah 0.41Ah 0.42Ah 0.61Ah 0.60Ah 1 month at 20 C 1.76V 1.86B 2.05V 2.02V 1.95V 1.99V
0.57Ah 0.65Ah 0.59Ah 0.54Ah 0.63Ah 0.62Ah 3 months at 20 C 1.38V 1.32V 1.48V 1.41V 1.99V 1.71V
0.51Ah 0.57Ah 0.48Ah 0.59Ah 0.61Ah 0.63Ah
The amount of vinyl retained on the separator after coating with the various vinyl solutions ranges from about 0.7 to 1.0 g / m 2 of separator material for the 0.5 wt% solution of vinyl in a solvent to to about 3.5 g / m 2 of material constituting the separator for the 3 wt.% solution of vinyl in the solvent.

Based on the weight of the separator (about 25 g / m 2), this would represent about 2.8 to about 14% by weight of vinyl starting from the range of 0.5 to 3% of solution used for the coating, respectively.

EXAMPLE 3
Several other cells were made as in Example 1 with some of the separators having a coating of 1% by weight of vinyl acetate copolymer and vinyl chloride in 3-pentanone. In addition, the lithium electrodes in some cells have been replaced by lithium aluminum alloy electrodes each weighing 0.52 g and comprising 85% by weight of lithium and 15% by weight of aluminum. Three batteries of each of the various types were stored under different conditions and then discharged across a 75 ohm resistor. The average voltages after one second and the average ampere hour numbers delivered are shown in the following Table V.

TABLE V
Alloy Electrode
Lithium Aluminum Aluminum Lithium Storage Conditions 1% "VYHH" Storage No Vinyla 1% "VYHH" No Vinyl Cooled 3,33V 3,40V 3,33V 3,33V 1 Week at 71C 1,50V 1, 08V 1.83V 0.98V
0.63Ah * 0.49Ah 0.42Ah 0.45Ah 1 month at 20 C 2.14V 1.82V 1.62V 1.20V
0,64Ah 0.65Ah 0.60Ah 0.62Ah 3 months at 20 C 1.48V 0.96V 0.98V 0.63V
0.58Ah 0.56Ah 0.53Ah 0.48Ah
* One battery.

EXAMPLE 4
Other cells were made as in Example 1 except that in each of them 0.479 g of a lithium sheet or 0.450 g of extruded lithium were used as the anode and the cathode collector was formed of 85 % by weight of carbon black and 15% by weight of "Teflon"; the electrolyte-cathode solution consisted of 2.4 cm 3 of 1M LiAlCl 4 in SO 2 Cl 2 and contained added lithium sulfide to the saturation point of the solution and the separator was coated with a vinyl solution as shown in Table VI. The batteries were stored under various conditions and then discharged across a 75 ohm resistor. The average voltages of the three cells, observed after one second and the average numbers of amperes delivered are shown in Table VI. In batch No. 8, the separators, after being immersed in the solution, were dried at room temperature for 2 hours. In the batch of NO 9 cells, the separators were dried for one minute at 1750C while in the batch of batteries No. 10, the separators were dried at 2250C for one minute.

TABLE VI
Batches of Voltage in volts after a second Amperes-hours batteries Solution of 1 week 1 month 3 months 1 week 1 month 3 months (3 batteries) Fresh coating anodes at 71 C at 20 C at 20 C at 71 C at 20 C at 20 C
1 Sheet 1% VYHH # SOCl2 3.23 2.38 2.86 1.13 1.12
2 In sheet 1% of VYNW. # SOCl2 3.26 3.00 2.58 0.81 0.92
3 In sheet 1% of VYHH.DIBK ** 3.16 2.80 2.76 0.99 1.14
4 Extruded 1% of VYHH.DIBK 3.03 2.99 3.05 1.06 1.13
5 Extruded 0.5% VYHH.DIBK 3.38 2.87 3.23 1.05 1.10
6 Extruded 1.5% VYHH.DIBK 3.29 2.17 2.42 1.13 1.10
7 Extruded 0.25% of VYHH.DIBK 3.03 2.51 2.49
8 Extruded 1% VYHH.DIBK 3.23 2.30 2.77 2.60 1.21 1.02 1.12
(2 batteries)
9 Extruded 1% VYHH.DIBK 3.31 2.67 3.16 2.49 1.22 1.31 1.09
10 Extruded 1% VYHH.DIBK 3.32 2.67 3.09 2.61 1.15 1.25 1.15
11 Extruded 1% of VYHH. 3.41 2.59 2.68 1.08
3-Pentanone
12 Extruded 1% of VYHH.DIBK 3.43 2.10 2.92 1.21
13 Extruded 1% of VYHH in the 2.91 2.75 2.63 1.07
2-Pentanone
* "VYHW is a vinyl acetate / vinyl chloride copolymer containing 97% by weight of
vinyl chlorite and 3% by weight of vinyl acetate.

** DIBK refers to diisobutyl ketone

Claims (8)

 A non-aqueous battery, characterized in that it comprises an electrolyte-cathode solution endowed with ionic conductivity, consisting of a solute dissolved in an active liquid cathode and an anode of active metal; a cathodic collector; a separator disposed between the anode and the cathode collector; at least a portion of the surface of the separator being coated with a vinyl polymer film.  2. Non-aqueous battery according to claim 1, characterized in that the monomeric unit of the vinyl polymer corresponds to the formula  tCH2 = CR R) in which Rx is chosen from hydrogen, halogens and  alkoxy groups having C1 to C4 alkyl radicals  C5; and RY is a halogen or an alkoxy group containing  C1 to C5 alkyl radicals.  3. Non-aqueous battery according to one of claims 1 and 2, characterized in that the amount of vinyl polymer film carried by the separator is from about 0.7 to about 3.5 g / m 2 of projected area. .  Non-aqueous battery according to one of claims 1 and 2, characterized in that the vinyl polymer is chosen between a copolymer of vinyl chloride and vinyl acetate, homopolymers of vinyl chloride and homopolymers of acetate of vinyl.  5. A non-aqueous battery according to one of claims 1 and 2, characterized in that the electrolyte-cathode contains a material selected from lithium sulphide and sulfur monochloride and mixtures thereof.  6. A non-aqueous battery according to claim 1, characterized in that the electrolyte-cathode contains at least one liquid oxyhalide selected from thionyl chloride, sulfuryl chloride, phosphorus oxychloride, thionyl bromide, chloride chromium, vanadyl tribromide and selenium oxychloride.  7. Battery no. aqueous composition according to claim 6, characterized in that the electrolyte-cathode contains an inorganic cosolvent.  8. A non-aqueous battery according to claim 6, characterized in that the electrolyte-cathode contains an inorganic cosolvent.