CA1276584C - Solid compounds based on superoxides exhibiting high ion conductivity, theirmanufacture, and related electrochemical uses - Google Patents

Abstract

The solid compositions based on superoxide of the invention comprise a material inert towards the O2 anions- playing the role of matrix with respect to these anions, and O2 anions - these compositions forming a material stable up to at about 100.degree.C. This matrix allows the mobility of O2- ions in this temperature range. These compositions can be used as electrolytes in an electrochemical cell.

Description

- 1 ~ Z, ~ s8 ~
"Solid compositions ~ based on ion-conducting superoxides ~ lifting, their manufacturing process and their electro applications ~
chemical ~ "~
The object of the invention is to ~ solid compositions ~ ~ base superoxides with ionic conduction ~ lifted, their manufacturing process9 and their electrochemical applications.
It targets, in particular, their applications as electrolytes in separation or analysis devices oxygen.
lo ~ 2 molecular oxygen is easily reducible to 1 ~ state anion due to its very electroactive nature which distinguishes from the other constituents of air (a ~ ote, rare gases) and many other gases.
The successive anionic stagesQ of the reduction of ~ 2 ~ 5 lead to ~ 2 (superoxide ion), 022 (peroxide ion) or ~ 2 H
(hydroperoxide ion) and, with rupture of the O-û bond, at 2 O ~
or 2 OH (oxide and hydroxide ions respectively).
The electrodiffusion of oxygen ~ ne souY anionic form has already been envisaged for s ~ adorn the oxygen ~ ne of a given medium.
Generally, a first electrode or cathode reduces the molecular oxygen to an oxygenated anion which migrates through an electrolyte up to a second ~ electrode or anode which oxidizes it by reforming molecular oxygen.
Several types of electrolytes have been propased to dry adorn oxygen by ~ electrodiffusion.
The most widely used electrolytes in phase liquid are constituted by aqueous solutions of potash and in solid phase with zirconia ~ doped with oxides such as those of yttrium Y2 ~ 3 or calcium Caû. The oxygen anions ~ s in play corresponds ~ respectively to the hydroxide ion OH and to the oxide ion O
In these two cases, the molecular oxygen undergoes a reduction tion with four electrons per molecule and the oxygen molecule is cut.
Very strong Qurtensions linked to the need to activate all the chemical and electrochemical reactions to ~ lec-~ 1 ~
. :

2 ~ 6 ~ 4 very high energy consumption very much higher to the energetic ~ th ~ oric of oxygen separation.
For example, in the case of a psr oxygen extractor electrodiffusion in a pota ~ se solution, the tension ~
apply to produce oxygen at 1 bar ~ from air atmospheric and the corresponding energy consumption have about 100 times the minimum values ~ given by the thermody-namique.
In the case of very conductive zirconia with very low temperature ture ambient3 it is necessary to heat above 600 ~ C
to obtain sufficient ionic conductivity and to activate the electrode reactions. The use of high temperatures causes psr elsewhere, problems of chemical reactivity in gas phase and corrosion problems of materials electrode.
Other environments were not considered but could not be developed such as molten salts based on alkaline nitrates operating at temperatures of about 250 ~. In that case, corrosion of electrodes and precipitation of peroxides have prevented the application of these media to the production of oxygen born. In addition, in a partial pressure gauge application oxygen, these media have temp ~ response of the order several hours ~, which makes them unusable in practice than.
Gas separation, and in particular extraction of the air oxygan are procedures ~ generally costly in energy. The electrodiffusion processes already mentioned on are particuli ~ rsment due to strong overvoltages of electro-also at large quantities of current required, or 4 faradays for one mole of oxygen transported.
~ Although significant efforts to reduce surten-have been undertaken in the field of oxygen electrodes for cells ~ fuel and in that of anodes ~ oxygen for electrolyte ~ e of water, the ~ most 30uvent solutions proposed use ~ an electrocatalysis using compounds ~ expensive ~
base of precious metals and / or organic molecules ~ synthetic delicate ~ te.

3 ~ 7 ~ iS89 ~
By Qilleurs, the high current intensities required when transporting one mole of oxygen ~ only involves 4 faradays cause energy losses by Joule effect both in the electrolytic medium and in conductors. vc ~ q In US patent 4,475,994, a method has been proposed.
electrochemical separation of oxygen from air or a gas line, using an electrochemical cell comprising a cathode where oxygen is reduced to ion ~ uperoxide ~ 2- and an ano-where the ion ~ 2 is reoxidized in û2, the transport of the super ion lo xyde being as ~ uré by an electrolyte. In this cell, the reaction oxidation-reduction involves only one electron per mo-02 school.
However, in this case, the sup ~ roxide anion produced by electrochemical way to csthode exists only temporarily, the time of its transport has 1 ~ anode where it is reoxidized: it re-it follows that in the absence of the application of a potential, the con-centering in ~ 2- is practically zero.
The concentration in ~ 2 during the operation of this cell proves insufficient for example for a production ~ a-satisfactory with oxygen, from a given medium containing it.
The work carried out by the Applicant has shown ~
that using appropriate superoxide3 compositions ~, it is possible to obtain a concentration of ~ 2 favoring the redox reaction of oxygen and, by 1 ~, the production oxygen.
The object of the invention is therefore to provide new positions do 3uperoxides conduction by ~ 2 elevation ~ e-It also involves providing a preparation process.
of these compo ~ itions and ~ els of superoxides of mi ~ e used easy.
The invention also ~ aims to provide electro-lyte ~ à ba3e de compo3ition ~ de superoxyde3 a ~ ensuring stability and mobility of ~ ion ~ ~ 2 ~ as well as electro-containing such electrolytes, usable in particular for the separation of oxygen from the air and the production of oxy-uncomfortable.
The solid composition3 ~ ba ~ e of superoxide of the invention tion ~ have csract ~ ris ~ e ~ in that they include:

4 ~; ~ 76 ~
- an inert material vis-a-vis superoxide anions 0z, playing the matrix role with respect to these anions, - superoxide anions ~ 2 ~
these compositions forming a stable material, ju ~ qu ~ a temperature not exceeding lOû ~ C approximately, 1A matrix allowing mobility ~ 2 ions in this temperature range.
By inert material vis-à-vis aniong ~ 2 means an essentially aprotic material and not comprising pa ~ of groups likely to react irreversibly with ~ 2 even under aprotic conditions, namely essentially:
oxidizing groups, Lewis acids, electro-centers philes or electrodeficient and systems that can lead to elimination in a basic medium.
The study of these compo ~ itionR shows that they have deq properties of high ionic conductivity, which makes them par-particularly advantageous as materials for the preparation of electrolytes.
They also have the advantage of ensuring a stable bility and mobility satisfai ~ antes of ions ~ 2 at temperatures-tures mod ~ r ~ es, in particular, ~ ambient temperatures of around lOO ~ C.
In the absence of any applied potential, these compositions solids contain a minimum concentration of super anions xyde ~ 2 of at least 10 milliequivalents per gram, in particular from 1 to 2 milliequivalents per gram.
Advantageously, the compositions of the invention have film-forming properties.
Composition ~ pr ~ f ~ rees are in the form of membrane whose ~ thickness is preferably less than 500 y approximately, advantageously of the order of 10 to 500 ~, in particular about 30 ~ 10 ~.
The matrix, according to a preferred embodiment of the positions of the invention is to bs ~ e of a macromol material ~ culai re.
Preferably, the macromol ~ cellular material is ~ basic of a homo or copolymeric polymer material ~ re, the case ~ expensive r ~ ticu the.

5 ~ 7 ~
, CP polymer material, capable of providing ionR ~ 2 a satisfactory mobility for use in electrochemistry, is more specially constituted ~ by a material at least ~ partial-ment amorphous at the working temperatures.
5It is also pr ~ preferable to choose a polymer material-re seizing the highest dielectric constant pos ~ ible.
Advantageously, the glass transition temperature Tg of the phase formed by the polymer matrix containing the anions ~ 2 is relatively low, below ~ 50 ~ C approximately.
loPlus particularly9 this Tg is 50 ~ C lower approximately ~ operating temperature.
This polymer material can be formed from a single type of polymer or copolymer. The polymer or copolymer can be neutral, a superoxide salt being dissolved in the polym ~ matrix -15riqu ~. As a variant, it includes loaded sites, more special ones.
ment, a majority of ~ ites cationiqueY, ~ 2 constituting one counter-ion ~.
According to a variant, more particularly when the wants to make a base polymer more amorphous and / or when 20scuhaite lower the temperature Tg of the composition, the material polymer is formed ~ of a mixture of polymers and / or copolymer ~.
~ Res copolymers are block or block copolymers (in which the sequence of patterns is regular) or even statistical cooolymers (in which the sequence of motif- ~ is performed at hassrd, which is opposed to ~ crystallization-tion of ~ channels).
Note that each compossnt of the mixture or copolymer can be advantageously chosen to improve a property given, for example, the smorphic character, the conductivity, the dielectric constant, hydrophobicity, resistance to temperature ~ temperature, film-forming properties, contact with a material neighbor laugh.
~ tDeY copolymers of this type include f -'type ~ P-CPOE-POP, in particular, those marketed SOU9 la brand / PLURACûL, each of which ~ eq poq bde a molar mass about 3000.
The general term polymer material also covers well the polymers used alone as the mixture ~.
.

6 ~ 2 ~ 65 ~
A first group of preferred polymers comprises alkylene lyoxides.
Among the polyoxides of alkyl ~ ne, propylene polyoxide lene (POP), formed of r ~ petitive units of formula -CH -CH ~ O

particularly suitable.
In general, the molar mass of the POP used work is advantageously of the order of 50,000 ~ 100 OU.
Polyethylene oxide (POE) whose constituent motives lo respond to the formula -CH2-CH2-0- also constitutes a polym ~ re suitable given its good solvating properties and the high value of its dielectric constant (~ = 4.5).
Its glass transition temperature varies from about -80 to -16 ~ C
as a function of molecular ma-Qse.
lS Since the solubility of POE in solvents organic strongly decreases when we pass a molar mass area of 106, it is advantageous to operate with mass POEs lower molecular, advantage of around 6,000,000.
A second group includes polyphosphaz ~ ne4, plu8 especially polyphosphazenes substituted by groups ether.
These are more specifically products comprising m ~ tifs of type:, GOLD
-N = p _ OR 'n in which R and R 'represent saturated hydrocarbon chains rees, possibly including one or more h ~ teroatoms preferably û and N, possibly associated with aro- groups matiques, and n is the number of patterns in the polymer.
In the group of polyphosphaz ~ nes, we can also use polyphosphazenes substituted by ~ groupings secondary amine, tertiary amine or ammonium function quaternary, alone or in combination.
It consists in particular of compounds comprising patterns of the type:

7 ~ 2 ~
f NHR 1 ~ 1 2 _ -P = ~; P = N-_NHR 'n ~ NR3R4R5 n dan ~ which R, R ', Rl, R2, R3, R4 and R5 are as defined above for R and R '.
A third group includes the polyamides ~ baYe pattern type: 7 RCN-o in which R and R 'are as defined above.
In a fourth group, the polym re used for the ela-boration of the matrix is a polyalkyleneimine, more special-ment a poly ~ thylèneimine substituted comprising units of the type ~ -N-CH2-CH2 ~ n with R as defined above.
The polymers of these different types are substituted, if applicable, it being understood that the substitutions retain the aprotic and inert character, vis-à-vis ~ 2 ~ of the matrix.
Advantageous substituted polym ~ res ComprQnnent chai-nes perfluoroalcoylQ.
According to another provision of the inventian, these polym ~ rescomport sites gr ~ ffés loaded or not, allowing the sol-transient vation of ~ 2-- The grafted ites playing the role of relay sites are mobile ~ and located in ~ out of lat ~ rs chsines, more than a few links of the carbon skeleton of the polymer baYe. The grafted site can ~ be constituted by a mctif of the po-lymares considered above ~ sus.
Preferably, these are grafts made up of ~
pyridyl groups.

Other grafts are of the sulfon ~ mide ~ - S - N - R 'type, with R and d R 'as defined above.
Yet another group of polymers includes one or more sieurs ré ~ Qine ~ contains exchangeable anions ~ by ~ 2 -Resins ~ preferred are constituted by resins quaternary ammonium comprising units such as:
8 3L2 ~ 5 ~ 4 - N- (CH2) n -, R ' and RR 'R R' in which R and R 'are as defined above ~ us.
The anions of the resin may be chosen in particular.
among the anionQ fluoride ~ chloride, hydroxide, iodide, tetraphe-nylborate, carbonate or acetate, previously exchanged, all or in part, by anions ~ 2-~
The resin used in the polymer material may be an homo or an ionic copolymer, produced from a monomer vinyl or allyl quaternary ammonium, alone or in copolymer-re ~ with other allyl quaternary ammonium monomers or different vinyl.
Advantageously, the use, for the preparation superoxide compositions according to the invention, a tet salt trapnenylborate and a poly (diallyldimethylammonium) salt per-puts to obtain superoxide compositions according to the invention tion having a ~ lev ~ e ion concentration ~ ~ 2 and having both a long service life and good thermal stability.
According to an advantageous arrangement of the invention, the ma-polymeric material further comprises alJ minus a capa additive ble, in particular to increase its dielectric constant and / or its amorphous character or ~ if necessary, make it less ~ by partially amorphous when it acts as a polymer of shouting tall or partially crystalline, and / or further promote the compatibility of the constituents of the composition.
Compounds ~ suitable for this purpose include polym ~ -re-Q, plu9 sp ~ cially the type of those defined above, from ~
agentQ plasticizer- ~ or 8el3, preferably ~ low reticular energy As plasticizers, mention will be made of ~ polar plasticizers -~ Z ~ 65; 1 ~ 4 g such as the ~ cyan compounds ~ s. The work carried out shows q'un compound which carries groups cyanées of the type 2,4,6-trimétho-xyben ~ onitrile is particularly suitable.
Alternatively, the dielectric constant is increased by using polym ~ r2s materials comprising groups-polar elements ~ carried by lateral chalnes ~ orientableQ.
Groups of this type include perfluoromethyl groups.
When the polymer material comprises several polymbers or copolymers, an observes that some 3uperoxide ~ allow to increase the compatibility of polymers. This Favorable effect is observed for example with tetrabutylammonium superoxide quaternary.
Appropriate ionic additives, in particular to increase ~ and / or compatibility ~ of the polymer (s) and / or copolymer ~ res Tire them and / or, if necessary, with the 8el of ~ uperoxide9 take NRI4 type A salts in which:
~ A- is an anion such as C104, B (C6H5) 4, Cn, F2n, + l 503 and -R represents a saturated hydrocarbon chain, capable of contain one or more heteroatoms, preferably 0 and N and n ' is an integer from about 1 to 10.
As neutral additives, mention will be made of compos ~ 9 comprising in particular a pyridine nucleus such as 2,2'-bipyridine.
Dan ~ the case where ~ the mechanical strength of the polymer must be reinforced, the polymer material defined below ~ us is present under for ~ e crosslinked or 90U8 tram ~ e form comprising, in particular, a frame formed from another polymer or copo-inert lymer with respect to ions ~ 2.
According to another preferred embodiment, the matrix containing the ions ~ 2- e3t the association of a liquid, possibly-lement g ~ lified, and a support con ~ constituted by a Qolide material authorizing the percolation of ions ~ 2 ~ that is to say the migration continues from ~ ion3 ~ 2 from one r ~ ion to another of the material.
Solid materials pr ~ féré have good performance mechanical and include ~ supports7 preferably thin, psr example based on glass or ceramic, such as fibers agglomerated glass ~ r ~ es, sintered glass or porous glass, or ~ ba ~ e 10 127 ~ 4 wettable, porous or swellable polymer impregnation, this polymber being inert with respect to the constituents killing the solution.
The liquid removed may be a molten superoxide salt.
S or in concentrated solution in a compatible solvent.
These supported materials have, in particular, the advantage good mechanical strength, high concentration of carriers ~ ions û2-) in the support and great mobility of these por-teurs. The problem of solvent evaporation is avoided when where the solvent is at low vapor pressure or gelled.
As indicated above, the matrix forms with the super-xyde a stable material at the temperatures considered ~ es.
Note that the term "superoxide" used alone in the description and the claims denotes the salt O + û2 formed with Cations C ~ mineral or organic ~.
According to a preferred embodiment of the invention, Cations C ~ represent ~ nt mineral cations.
Suitable mineral superoxides include the super-roxides of monovalent metals, more especially alkali metals lins, such as Naû2, K02, RbO2 and Csû2. Other superoxides take transition metal superoxides as complex.
According to another embodiment, particularly preferred due to 3 high compatibility properties of ~ uperoxides with the ~ polymer materials of the matrix, the ca-C + tions represent one or more organic cations. From ~
super oxides of organic cations specially ~ preferred for the implementation of the invention include ~ superoxides of ammonia nium q ~ otsrnaire used alone or in mixture.
Among the products of this type, there will be mentioned superoxides of quaternary tetraalkylammonium NR4 + û2 dan ~ which R re-has an alkyl radical of pr ~ ference of lb lO atom ~ of carbon approximately.
Dea superoxide ~ of this type include superoxide quaternary tetramiethylammonium TMA + 02, the - ~ tetrabu- uperoxide quaternary tylammoniun TBA + 02 and tetrahexylam superoxide quaternary monium THA + 02 -11,127 ~ i584 Ruperoxide TMA ~ 02 is particularly advantageous due to its great stability (it melts around 97 ~ C and decomposes se at a slightly higher temperature and its solubility raised in several organic solvents (about 0.05M danq acetonitrile).
In a variant, the alkyl groups of the cations t ~ -traalcoylammonium superoxides used are replaced by ether groups, for example, of structure - -- ~ (CH2j2 ~~~ n CH3 in which n is an integer, preferably ~ rence from 1 to 5 approximately.
According to another variant, the superoxides used for the seeding is solvated by the solvent or solvents used vre for their preparation, most generally pyridine.
This solvation advantageously leads to a fa-vorable on the stability of the system.
The compositions of the invention are prepared by incorporating anion poration ~ ~ 2 in a matrix as defined above sus. This incorporation operation corresponds to a sowing-ment of the ion matrix ~ ~ 2.
According to an alternative embodiment, the incorporation is carried out chemical ration in the presence of a solvent in which the matrix and the superoxide are soluble or can be made solublea ~ using additives.
The solvent mi- ~ used is an aprotic solvent such than pyridine, benzene or toluene.
When the superoxide ael is a mineral salt, for facilitsr ~ olubili-Qation of salt and / or increase the size of cations in order to decrease the potential well that it constitutes for anions, we use according to classical techniques a alkaline cation complexing agent such as a crown ether or a cryptand.
According to another alternative embodiment, the seeding in o ~ e ~ t performed electrochemically by cathode reduction dic of molecular oxygen according to the method described in the brief vet US 3,102,140 on behalf of Callery Chemical Cy.
In a preferred way, the incorporation of aniona 2-in the electrochemical m.trice is r ~ performed by replacing 12 ~ 2 ~ 5 ~
anionR electroactive préexiYtant in the matrix, lesditq anion ~
being ~ limin ~ s psr anodic oxidation as the creation of ions 0 ~ ~ a cathode subjected to a flow of oxygen gaseous or dissolved.
S To prepare derivatives of superoxides sou ~ form of membrane, we proceed ~ the evaporation of ~ solvents or a diaper consisting on the one hand of a solution of the constituent material the matrix and on the other hand a ~ olution of ~ el of superoxide, these solutions being degassed.
lo Evaporation is carried out, preferably ~ under current dry gas such as nitrogen and temperature controlled ~ e. We use a flat support in an inert mat vis-à-vis the reagents using, for example, polytetrafluoroethylene (PTFEj. After evaporation of the solvent3 or membrane3 formed ~ are dried.
According to a ~ advantageous position of the invention, which increases the conductivity, the membrane is subjected at least one annealing operation, preferably a temperature slightly lower than the melting temperature of the material the matrix in ~ emencée, insofar as the superoxide is not no degradation ~ at this temperature.
To improve the mechanical strength of the polymer material, the base polymer is screened using another polymer or copolymer according to conventional techniques.
One can also crosslink the material before, or, the if necessary, after ~ incorporation of ~ uperoxide, in particular by irradiation or UV photocrosslinking.
The ~ quaternary tetraalkylammonium superoxide NR4 + 02-can be prepared mani ~ re clas ~ iqua by electrolysis of a tetraalkylammonium halide NR4 + X ~ in which R is such as defined above and X represents a halide ion ~ nure and r ~ duke-oxygen or, according to another variant, by a reaction solid-solid followed by extraction, as described in Inorg.
Chem. 1964, 3, 1 ?, 1798-9, and 1983, 22, 18, 2577 ~ 3.
The ~ ~ uperoxydeq NR4l02 peuv8nt ~ be pr ~ prepared by a metathesis reaction between:
a - a quaternary ammonium salt whose inert anion vis- ~ vis of ~ 2 e9t chosen pr ~ f ~ rence from the ~ anions F, I, OH, N03, 13 ~ Z'7 ~ Sl ~
C104- ~ ~ Ph4, CH3COO, C03-- and b - an excess of superoxide whose cation is a metal cation alkaline, preferably K + or a quaternary ammnnium cation, preferably TMA + ~
This metathesis can, indeed, be carried out as a reaction solid-solid, according to the above US patent, followed by an extrac-tion of NR4 + ~ 2 dan ~ NH3 liquid.
In accordance with an original availability of the invention, the metathesis reaction is carried out in an organic solvent such as benzene, toluene, ca ~ appropriate, dimethylsulfo-DMSO xyde, and preferably in pyridine.
The electrochemical study of compositions based on super-oxide above allowed to highlight their ~ properties of high anion conduction and this, advantageously, in a temperature range from ambient to approx. 100 ~ C
Ron.
This ~ compositions allow more especially the diffusion of oxygen in the form ~ 2- while constituting a barrier impermeable to other non-ionizable gases ~ under the same conditions tions that ~ 2 The invention therefore relates to new electrolytic materials.
based on superoxide compositions as defined above.
Note that the con3titusnts of the electrolytic material have good ~ chemical stability vis-à-vis ~ 2 but also towards Yi ~ chemical ~ rePecies ~ possibly produced by the reactions of û2 with the impurities of the material, in par-particular ViS- ~ -Vi9 of peroxidized species (peroxides) hydrope-roxydes, peroxydates) resulting from the dismutation of ~ uperoxydes.30 The presence of any element favoring or cstalysing dismuta-tion of ~ uperoxydeq must therefore ~ be avoided.
The electrolytic material can furthermore be conduc-cationic insofar as the9 cstions are not too much bulky and where their diffusion does not limit the conductivity anionic.
According to another provision of the invention, this material electrolytic is made electronic conductor for example 1 ~ ~ Z'7 ~; $ -! 34 by incorporating electronic conductive particles such as as particles of carbon or magnetite Fe304 These materials rials have the advantage of being able to be used in dea devices involving a partial pressure difference of oxygen instead of a difference of electrical potential.
This electronic conductivity is however not haitable when using an electric generator in the cooked, or when looking for ~ g ~ generate an electrical voltage because it would lead to loss of energy or self-discharge.
By taking advantage of the film-forming properties of materials matrix electrolytes, the electrolytes of the invention are advantageously carefully prepared in the form of membranes, which allows install large areas.
Preferred membranes have thicknesses inf ~ -less than 500 ~, in particular around 10 to 500 ~ before-approximately 30 ~ 100 ~.
Particularly advantageous matrix materials for the development of homogeneous transparent membranes3 including nent a polymeric material, sn particular, an alkylene polyoxide lane as defined above.
High conductivity electrolytic membranes include a copolymer, especially a static copolymer tistique with OE (thylene oxide) and OP (pro-pylene).
The percentage of OP reasons and advantageously at least minus about 5%, preferably about 40 ~ in the copoly-mother whose molecular weight is higher especially around from 50ûO ~ 50û 000.
Other membranes ~ include a blend of polymers and one or more additives.
Ges proportions pond ~ rales preferred ~ of constitusnt ~
of the membrane, mixture of polym ~ re ~ / additiveq / superoxides, are about 6/1/2.
Advantageous membranes of this type are ba ~ s POE
and include another pclymere such as POP, pr ~ férenca according to a ratio of about 4/2.
As composition, mention may be made of POE / POP / additi ~ such that 15 ~; ~ 7 ~ S5 ~
THAP (tetrahPxylam ~ onium perchlorate) / superoxide salt such as TBAO ~ according to the weight proportions of about 3b5 / 2/1/2 or again, POE / POP / additive such as THAP / superoxide such as K02 / agent complexing agent such as crown ether 18-crown-6 according to the proportions S tions of about 3 to 5/2/1 / 0.4 / 0.4.
the invention also relates to devices or cells electrochemicals for selective oxygen transport clearance, like oxygen and current carriers, of ions ~ 2 moving within Jn electrolytic material as defined lo above.
Preferred cells are characterized in that they comprise the electrolytic material, advantageously in the form of membrane, confined between two coextensive electrodes facing against face with said film, this ~ ele ~ trodes being c ~ nstituées of a conductive material which is permeable to gases, porous, inert towards screw of the mat ~ electrolytic line at temperature below ~ 100 ~ C
and stainless at least as regards the anode.
The materials of the two electrodes are identical or different.
The electrolytic chain developed from electro-lytes of the invention corresponds to the following sequence: (medium 1) cathode / electrolyte / anode (medium 2).
Molecular oxygen from medium 1 is reduced at the cathode in the state of anion ~ 2 by a monoelectronic reaction ~ 2 + e ~~~~ ~ 2 quasi-reversible in the absence of protons in the middle.
The ion ~ 2 diffuses into the electrolyte and will discharge has 1 ~ anode according to a reaction also mnno ~ electronics, almost reversible ~ corresponding to the equation: ~ 2 ~ e ~ + û2.
Oxygen can combine with the metal or material of the anooe if the latter is oxidizable, or is released in gaseous form in the opposite case.
We will note with interest that the global reaction responds to the transfer of one oxygen molecule for each ~ lec-3 ~ tron switched on when four electrons were needed reR in the prior artO
In addition, it should be noted that it does not occur at any time for cutting the oxygen ~ ne-oxygen link, the superoxide ion being : ..
16 ~ 2 ~ 76 ~
a molecular ion.
The implementation of reversible processes, both cathode than at the anode, reduces the activation energy to bring to the system ~ oit SOU8 form ~ electric or soua form thermal (gain in operating energy cost), either by catalytic means ~ (investment gain).
In general, it is thus possible to decrease significantly overvoltage at the electrodes, to lower operating temperatures and simplify, danY the ~
electrochemical devices used, dzs technology trodes which will not have to carry out a particular electrocatalysis particularly delicate in the case of OH- ions.
The ~ electrode materials are specially chosen from leq materials able to ac ~ accelerate the redox reaction ~ 2 (adsorbed) ~ e -> ~ 2 and does not cause dissociative chemisorption of the oxygen molecule.
Suitable materials include personal materials.
carbon-gas-permeable, for example vitreous carbon or graphite, possibly mechanically supported by a conductive or non-conductive weft, for example a polypropylene fabric.
Carbon can be incorporated SOU3 in the form of particles and / or fibers dispersed dan a mat ~ riau polymare.
The carbon-based conductive material may also be ment formed of a possibly woven sheet, a felt or a carbon paper.
Other suitable materials include a slightly stainless metal or a form dispersed in a polymeric material or SOU8 form of tablecloth ~ possibly woven.
For the cathode, the metal can be formed from coated steel green of a dep ~ t for example of platinum or nickel.
According to an alternative embodiment, the electrodes ~ have made up of a combination of materials.
One type of combination includes a weft of a polymer, with high resistance properties, supporting a film very thin electronic conductive polymer itself ~ charged me ~
glassy carbon powder or an au ~ re product ensuring a good electronic transfer.
17 ~ ~
According to another type of cumbing, the electrodes ~ are formed of one or more materials giving them conduction properties both electronic and ionic vis- ~ -vi3 from ~ 2.
According to another variant, the electrochemical dispo3itif ~
includes, interpo ~ é between the electrode and the electrolyte, a film a mixed conductor, electronic and ionic, in which ~ 2 is soluble, which allows the reduction of ~ 2 in a large volume and not p8S only ~ the electrode surface-lo ~ electrolyte.
According to yet another variant, the electrodes are formed of an asymmetric system, the cathode side promoting gas flow to limit the polarization of the phase gas and re ~ embrace electrode reactions ~ reduction from ~ 2 to a single electron, and the c8t ~ anodic faYorisant the oxy-dation of ~ 2 and the departure of gaseous oxygen.
Satisfactory performance on an industrial scale are obtained using large area membrane devices nes and high compactness.
According to an advantageous method of implementation, ce3 available sitif ~ come in the form of small modules of a few tens to a few hundred m2 each ~
These include cylindrical modules where the membrane is wound in a spiral, of the type used in permeation carbonated classic. In these cylinder ~, the coiled layers ~ es Advantageously follow one another as follows: cathode / membrane / ano-of / membrane / cathode ... Cathodes on the one hand 9 anodes on the other hand are permeable ~ to ga ~ and d ~ not ~ ent each of a c ~ tee of the cylinder in the axial direction so ~ be connected to the current leads. The gas circulation is carried out according to the mode known as currentY believe ~ s inside the por3 electrode3 ses, oxygen being collected in the axis of the cylinder.
Another suitable type of module includes setting up forms membranes in the boxes with con ~ titution of "sand-cathode / membrane / snode wiches, accordion-folded dan ~ le bo ~ -tier constituted psr example by mat faces ~ insulating risu gas tight and conductive faces R distributing current and gas.
'18 ~. ~ 7 ~ 84 The modules are grouped in series, in parallel or in parallel series According to yet another aspect, the invention relates to a method selective oxygen transfer from a first medium to a second medium in which electrochemical reduction is implemented of oxygen ~ only leading to the transient formation of ions ~ 2- ~ the diffusion in ~ 2 form in ~ electrolytic material such as defined above, which also constitutes a practical barribre only completely impermeable to other gases, and oxidation lo in oxygen ~ 2 ions.
In a preferred mode of carrying out this process, imposes a potential difference, ~ using a generator electric outdoor, across the electrodes of a cell such as the as defined above, separating the ~ environments mentioned above.
The electrode El used as a cathode is adjacent to the first medium and that used as an anode E2 is adjacent in the second ~ middle.
Under these conditions, the oxygen in the medium l is consumed at the level of the El electrode: an electrochemical reaction of reduction transforms it into ~ 2 ions which migrate to the elect Trode E2 ob takes place an electrochemical reaction opposite to the previous one (oxidation of the anion in oxygen which is released in the middle 2).
The assessment of this process chain is a transfer of oxygen from medium l to medium 2, obtained at the cost of one consumption tion of electrical energy.
It will be noted that it is also possible by this process ~ to decompress oxygen ~ not dan ~ the anode compartment.
According to another mode of realization ~ ation, we have ~ sure the transfer s ~ oxygen read from a first medium ga ~ them at a pressure partial oxygen ~ not called high in a second medium ~ pressure partial lower oxygen, maintaining a difference partial pressure between the media considered3 ~ sparse ~ s an electrochemical cell, as defined above. This partial pressure difference provides an electrical voltage E
across the electrodes.
This voltage can be used as an electrical generator.
19 ~ .Z7 ~ 8 ~
cudgel: concentration pila operating between two pre3sion ~
partial oxygen imposed Pl and P2, or battery ~ chargeable in the case where the oxygen produced at the electrodes E2 is consumed by an irreverible chemical reaction ~
The voltage that appears between cathode and anode when it there is a difference in partial pre ~ ion of oxygen between two gaseous media can be used to make a gauge to oxygen operating at room temperature. In this case, the pres-Partial oxygen release from one of the media is used as a reference.
lo ~ ernst's law gives the value of the measured voltage (without current bit) E = RT log P
F ~ P ~
the number of electrons involved in the electrochemical chain being here of 1, R ~ being the constant of the ideal gases, F the value faraday and T the absolute temperature. It should be noted that the voltage E delivered by this type of gauge is 4 times higher than that provided by the gauges using a conductive electrolyte ~ 0 tor by OH or o2 ions.
In a particular mode of use, when it exists a difference in partial oxygen pressure between two media gaseous separated by the electrochemical cell described above, the two electrodes are connected ~ by a passive external circuit carrying a conductor of low electrical resistance and an inter-breaker. Such a device makes it possible to control (has its ~ oir of regu-ler or interrupt) the flow of oxygen which passes from medium 1 to bearing the plu8 high partial pressure of oxygen ~ towards the middle 2. When the switch is in the closed position, the cell is short-circuited and oxygen is transferred from medium 1 to medium 2 by migrating 80U9 as a superoxide, the mi3 electrons involved to the electrodes circulating in ~ the external conductor ~ When the switch is in the open position, a voltage appears at electrodeQ, mai3 the electrons ~ cannot circulate in the cir-cooked outside, the oxygen flow between the medium ~ 1 and 2 is interrupted (it is in fact limited to the permeation flux of the oxy-neutral molecular gene ~ through the electrolyte membrane).
- 20 ~ 7 ~
The "all or nothing" control thus carried out can be refined by the introduction of a variable resistance in shelter in the external circuit: current measurement allows control so very preciqe the flow of oxygen that is transferred from middle 1 in middle 2.
It is clear that this very simple route can lead to a real slave system allowing for example to tabiliate or to program the partial oxygen pressure of one of the two half places.
According to yet another variant, if the electrolytic medium that not only allows the diffusion of oxygen in the form anionic but also electron transport, the system can then operate as a "semi-perm ~ able" ~ lective membrane to oxygen. The term semi-permeable is not taken here in the classical concept of permeation: the selectivity of the membrane for oxygen is not pa ~ due to a diFfu ~ ion pref ~ ren-tial of dissolved neutral molecular oxygen may ~ at pre-sence and mobility of oxygenated anions and electrons.
The general operating principle is as follows:
electronic conductivity leads to a partial short circuit of the member. This short circuit gives rise, or the action of a partial pressure difference of oxygen between the two faces of the membrane with der current3 electronic and ionic which cancel each other out but whose balance sheet is a transfer of oxygen from one side of the membrane. The semi- flow perm ~ ability increases with temperature. Electro-conduction nique within the material itself has the advantage, compared 8U if the ~ electrons return by an external circuit, distribute the current evenly across the membrane.
More precisely, if there is a pressure difference partial oxygen ~ ne between the two faces of the membrane, oxygen ~ ne can be reduced sn anion oxygenated in contact with the membrane of the cBté high pressure, then migrate ~ trsvers the membrane by diffu Zion before ~ being oxidized to oxygen ~ ne of the low pressure side. The 3 ~ librons lib ~ res from the low pre ~ sion side can then migrate to the high pressure summer by diffusion ~ through the medium electrolytic ~ mixed conduction (ionic and electronic).

The selectivity of the oxygen transfer provided by the available ~ itif ~ from the inventiun le5 makes it particularly suitable for applications relating to oxygen separation.
Such applications include the production of oxygen '5 by concentration from air, in particular dry air, preferably low acid gas content such as C02, 5 ~ 2 or SH2, for industry or in the medical field, purification of oxygen-containing gases, the introduction of con-of oxygen in a gas, the analysis of gaseous media.
lo Other characteristics and advantages of the invention are reported in the following examples and with reference to it to the figures.
Figure lb represents the magnification of a part of the cell of a device according to the invention shown in figure la.
Figure 2b shows a fold of the modular element of FIG. 2a of the sandwich type.
Figure 3 shows the same module in section.
EXAMPLE 1 Preparation of a superoxide-based composition of POE POP / TBA02 in the form of a membrane.
ûn proceeds to the development of a solution 1 of polymer and of a solution 2 of tetra-n-butyla ~ monium superoxide, in operating as follows:
Solution 1 One dissolves 4q of POE of my molecular ~ 600,000 (Aldrich), 29 from POP (Hercules Co, under the name of Parel 58) and 19 from per-tetra-n-hexylammonium chlorate (Alfa Ventron) in an amount ~ Enough pyridine (Prolabo) to make 10 ml of solution.
This solution is strongly stirred for about 15 hours.
Solution 2 a mixture 19 of tetra-n-butylammonium fluoride (TBAF) trihy-draté (Fluka) with 2.59 pota superoxide ~ sium (purity ~ 6.5 X) (Alfa Ventron) in a sufficient quantity of pyridine (Prolabo) to make 15 ml of solution. We leave the reaction of metathesis be done with stirring for 10 8 30 minutes.
It is centrifuged, the liquid part is recovered. We then resume the solid with 15 ml of pyridine. We centrifuge and r ~ cupère 18 liquid part. The solution obtained by bringing together ~ the two 22 ~ 2'7 ~
liquid fractions, i.e. ~ 0 ml in tDUt, contains approximately 0.69 tetra-n-butylammonium superoxide.
Solution 2 is mixed with 30 ml of solution 1 with stirring for 10 to 30 minutes A vacuum is created above the solution (approximately 20 mm Hg) to ~ vaporize approximately ~ 0 ~ of the solvent. We can heat up to 35 ~ C maximum to accelerate the evaporation.
We obtain about 30 ml of yellow viscous solution, which we pour into a flat-bottomed polytetrafluoroethylene container. We evaporates the solvent in a stream of dry nitrogen for a period of time 12 to 3 p.m.
We invert the membrane and continue the evaporation during less ~ 3 hours.
A 90U9 film is thus obtained in the form of a homogeneous yellow membrane.
very pale which contains POE / POP / THAP / T8A02 according to the parts in following weights: 4/2/1/2. The conductivity of this membrane 2û ~ C is 4 x 10 7 Q 1 cm ~ l and at 50 ~ C
of 5 x 1o ~ 6 Ql Cm-l This membrane lends itself very well to rolling between two rollers polytetrafluoroethylene up to thicknesses of the order of 20 microns.
EXAMPLE 2: Variants of preparation of solution 2 (TBASj:
Ut; ili ~ ation do an ~ on flu ~ rur ~ as anion starting point ~ Solvent: tolubne.
49 of T8AF trihydrate in 3CO ~ 1 of tolubne are added and azeotropically distilled at about ordinary pressure three ~ quarters of toluene. The solution is cooled and added K02. The mixture is stirred for approximately 8 h and then filtered under nitrogen to remove solid products. We add to the filtrate an identical volume of dry cyclohexane. A disturbance appears.
Cool to -20 ~ C to crystallize the product which form. The necessary quantity of T ~ AO ~ is redissolved in the pyri-dine to get solution 2.
We can also prepare superoxide compositions tetrabutylammonium (TBAS) using ~ starting anions other than fluoride and less hydrated than this, for example ~
ple carbonate, iodide or acetate, following the mode operative below:
23 ~ 84 Use of rarbunate ~ nt ~ nt as anion de ~ de ~ port First, tetrabutylammonium carbonate (TBAC) is prepared by bubbling CO 2 gas in a methanolic solution tetrabutylammonium hydroxide and then evaporating the methanol.
S Then the TBAC crystallized ~ white is dried, then redi ~ sout le TBAC in pyridine (part of the product remains in suspensionj and add to this solution an excess of potassium superoxide previously crushed. After stirring the solution for ques minute ~, the solution is filtered to separate K02 and K2C03 and o a solution of TBAS is collected in pyridine.
The reaction is written -pyridine (N Bu4) 2 C03 ~ 2 K3 ~ -> 2 N Bu4 û2 + K2 C ~ 3 Use of iodide as anion of dKp ~ rt The anions ~ 2 and I- can also exchange 9 'in ~ cases specific goods where the network energy of the products formed plays a role a great role.
If powdered sodium or potassium iodide is added to a solution of TMAS danq pyridine, or better in acetoni-trile, we observe the immediate precipitation of tetram iodide-thylammonium (TMAI), the network energy of TMAI being very high important. On the other hand, in dimethylsulfoxide, TMAI is much more soluble blow and separation of TMAI from ~ quperoxide formed is much more difficult. This rapid precipitation of TMAI
dsns CH3CN still opens a new way of preparation for TaAS
and other ~ quaternary ammonium superoxides.
It suffices to exchange ~ 2- and I- between TMAS and the iodide of tetrabutylammonium TBAI in CH3CN. The TMAI precipitates and, after filtration, a solution of TBAS dan ~ CH3CN ~ is collected.
tion is as follows:

N Me4 ~ 2 + N ~ u4 I> N Me4 I + N 9u4 ~ 2 These reactions with iodide ~ can not be applied in pr ~ 3encede iodhydrate. The ammoniums must indeed be quaternary (4 chains other than H Rur the nitrogen atom).
Using the ~ c ~ tute co ~ m ~ anion from start It is also possible to prepare solutions of ammonium superoxides.
, 2 ~ 7 ~ 584 quaternary niums from the corresponding acts. Parex ~ mple, dQn8 le ca ~ de N Bu4 ~ 2 ~ the preparation method is the next one:
ûn first makes t ~ trabutylammonium acetate by pouring drip of glacial acetic acid in a Rolution methanolic tetrabutylammonium hydroxide until the pH reaches approximately 4. The methanol is removed in an evaporator rotary without exceeding 50 ~ C then poured over the precipitate ~ a little of acetonitrile which is chased again.
o Then put the acetate in pyridine and add ~ ute K02 groy ~. Acetate is insoluble in pyridine, just like K02, but the exchange between the anions ~ ~ 2 and CH ~ CûO takes place then-the solution turns yellow a ~ sez quickly and contains tetrabutylammonium superoxide.
The reaction, which is written:
pyridine N Bu4 CH ~ COû ~ K02 ~> N ~ u4 ~ 2 + CH3 C ~ û K
is not quantitative, however.
The methods described above are relatively gentle since reactions occur at room temperature and therefore do not involve rapid degradation of superoxides to solution during their preparation. Anyway, we can extract the ammonium superoxides from the solution in which they have been prepared so as to isolate them from the different constituents (anions, ~ olvants ...) of the reaction medium, these which can cause slow degradation of the superoxide.
EXAMPLE 3 Preparation of a superoxide composition containing .
poly (diallyldimethylammonium chloride) The reagents used are:
. Poly (diallyldimethylammonium) chloride (abbreviation PDADMAC) ~ 15 ~ en ~ olution dan ~ l'eau (réf 6515 de Polysciences, Wsrrington, Pennsylvania, United States ~).
. Sodium tetraph ~ nylborate (rgf 72020 Fluka-CH) . Tetrabutylammnnium superoxide solution in pyridine prepared by metathesis between tetrabutylammo- fluoride nium pentahydrate and potassium hydroxide ~ qium . Pyridine (Prolabo-France) ~ 2 ~ ~ S 8 ~
We first prepare the tetraph ~ poly nylborate (diallyldim ~ thy-lammonium) (abr ~ viation PDADMA-TPBj by ~ change of C1 ions and BPh4 in 1 esu according to the reaction:
s ~, Nal 3Ph4 ~ ~ Na + Cl e me me _ Cl ~ n ~ BPh4 - n PDADMA-C PDADMA-TPB
PDADMA-TP ~ quantitatively precipitates in the form of White powder. It is dried by heating at 60 ~ C under Yide pen-within 24 h. The replacement of C1 ions by BPh4 ions is almost 100 Y.
Dry PDADMA-TPB is dissolved in pyridine (or DMSOj at 20DC then poured into the solution obtained a solution of tetrabutylammonium superoxide N (C4H9 ~ 402 L9 suDeroxide ae poly (diallyldimethylammoniumj (abbreviation PDADMA S) precipitates in the form of white powder ~ hâtre. It is dried under vacuum at 20 ~ C.
The total percentage of Cl or BPh4 anions substituted by ~ 2 is measured by dosing the ions ~ 2 by volumetry. We measure the volume of oxygen released when reacting the solid product of and dry obtained with an aqueous solution of ferric chloride FeC13 (1M) and hydrochloric acid (1M).
the overall reaction is as follows:
2 ~ 2 + 2 H ~ H20 ~ 3/2 ~ 2 The me ~ ure ~ performed ~ show that dan ~ the PDADMA-S
obtained by two methathe ~ e ~ successive ~, about 60 Z of the anions present in the oolymer ~ are anions ~ C ~, the anions res-tants being BPh4 ~ since the first ion exchange is ~ t ~ i total). This corresponds to approximately 2.5 milliequivalents of ~ 2 per gram of polymer although the ma ~ molar BPh4 anions 3s is very high.
The PDADMA-S, stored under vacuum ~ 20 ~ C, remains intact during for several weeks and its physical appearance is not changed , 26 ~ Z ~ 6 ~ 4 up to ~ 170 ~ C (Kofler bench test). This thermal stability is significantly higher than that of tetramethylam superoxide monium (TMASj which melts at 97 ~ C and decomposes around 100 ~ C.
The quaternary polyammonium ain ~ i prepared, of which approximately 60 ~
anions are ~ 2 anions (the other anions are Cl and BPh4), has excellent thermal stability and has a very long lifetime.
To make the ~ 2- ions mobile in the polymer, we laminates PDADMA-S with low mass polymers (between ~ 00 and 12QO environj which solvate the ions ~ 2- so as to separate these from their counterions belonging to the skeleton. These plastic-fiants can be chosen, for example, from polymers capable of solvating the ions ~ 2 by hydrogen bonding, by example polyethyleneimine, prepared by alkaline hydrolysis of polyoxazoline according to the method described by T. SAEGUSA et al, J. Am. Chem. Soc. (1985), lû7, p 3823-3828.
PDADMA S can also be made amorphous by others.
means such as:
. Replacement of methyl groups by groups having several ~~ links -CH2-, for example butyl or hexyl.
. The copolymerization of diallyldimethylammonium chloride with a vinyl ether or another vinyl monomer compatible with û2 ions (example: methyl-vinyl-ether perfluor ~ j.
EXAMPLE 4 Film based on POP / TBAO
2s We proceed as in Example 1, by submitting a lution of POP (3 parts by weight) and a solution of TBA02 (1 part by weight) ~ a coevaporation operation.
The membrane obtained is SOU3 in the form of a paste sticky which improves the mechanical hold with a weft non-woven polypropyl ~ not introduced before evaporation.
EXAMPLE 5: Oxygen transfer ~ through a seeded membrane in anions ~ 2- 'by application of an electric voltage only at the terminals ~ of a mounted electrochemical cell ~
with this membrane The ~ tests were carried out with the assembly shown in figure la. Figure lb ~ represents a large ~ issement in section of a part of the electrochemical cell.
27 ~; ~ 76 ~
The membrane (lj whose preparation and composition are described ~ in Example 1, has a diambtr ~ of 60 mm and a thickness close to 150 microns. She is pressed between two carbon nonwoven webs (2aj and (3a) (International Paperj which act as porous electrodes. The tablecloth sandwich carbon-membrane-carbon sheet is itself pressed between the sintered stainless steel discs (17) and (18d.
The room (19d which has inlet and outlet ducts ~
gases (20) and (21) has a volume of approximately 50 cm3 and plays the role cathodic compartments.
The chamber (22d is connected by the outlet duct of ga ~ (23) to a pressure sensor and its total volume, i.e.
say including tubing, connections and dead volume of sensor is 3 cm3. It plays the role of an anode compartment.
The entire cell is thermostatically controlled at 4 ~ .0 + 0.1 ~ C
by circulation of water in the brass blocks (24) and (25d.
Before starting the device, the chamber (19) is filled with oxygen at 1 bar and the chamber (24) is filled oxygen at 1005 mbar. The two compartments are rigorous-2C waterproof.
After stabilization of temperature and pressure an electrical potential difference of -0.8 V is applied between cathode and anode. Current intensity is 300 ~ A
at the start of the experiment and quickly stabilizes around 60 ~ A
After passage of a quantity of electricity of ~
1.67 x lû-l C measured, in 30 minutes, by a coulom ~ tre, we cons-that the pressure in the chamber (22d is not ~ 1005 ~
1017 mbar, which corresponds to the production of 1.37 x 10 6 mole of oxygen ~ ne for 1.73 x 10 6 Faraday having passed through ~ the cell. The Faradic ratio, close to 1, indicates that the oxygen transfer ~ -was therefore not carried out ~ by the intermediary of superoxide anions ~ 2 EXAMPLE 6: Accordion-type module used as a device electrochemical to separate oxygen from the air.
FIGS. 2a and 2b relate to a variant of an arrangement modular tuning type ~ on and represent respectively a cutaway view of a module and the d ~ tail of a folded section.
The module is composed of a membrane assembly ~ lectrolyti-._ - 28 ~% 7 ~
que-electrodes (1,2,3) folded in accordion inside a waterproof rectangular box with four insulating fac ~ s (4,5,6,7) and two ~ conductive sides (8,9) used for faith of current and gas. The membrane (lj of the type from that described in ~ example l is sandwiched between two layers ~ R of ~ porous electrode atrial (2) and (3d for example graphite cloth. The composite film thus formed is folded in accordion. It is useful to insert, between the folds, ~ layers (14d of a conductive material ~ very easily permeable electric ble au gaz, for example, a corrugated metal grid, the lerdle of which, on the one hand, maintains between the folds of the Film a space allowing easy circulation of gases and optimizing them the ride, on the other hand, to provide good electrical contacts distributed on the surface of the electrodes.
The two extremities of the stack thus produced perpen-particularly to the folds (10 and 11j are made gas tight, for example, by drowning them in an electrically insulating resin epoxy or silicone type. They are applied tightly against the two faces (4) and (5d of the bo ~ tier.
In addition, each of the ends of the membrane composite ne- ~ electrodes parallel to the folds (l and 13) is connected fa-waterproof and over their entire length ~ one of the iso- plates lantes (6 and 7) of the housing.
Figure 2b shows how each of the layers electrode (2) and (3) surrounding the electrolytic film (lj is in electrical contact at the folds with one of the two face ~ conductive (8) and (9).
Figure 3 shows a section of the module in the plane perpendicular to the folds ~ located at the gas pipes (15) and (16).
It also shows how the package / film system accordion site delimits two regions A ~ t B isolated one of the other vis-à-vis gases and electrically.
Channels are arranged in the faces (a) and (9), of so that each of the compartments ~ A and B communicate with the ~ end caps (15), (15 ') and (16), (16') respectively, end caps 2g ~ Z7 ~
connectable ~ to external gas circuits.
The module thus constructed is used to produce oxygen taken from the air. The operating mode is the following: weakly compressed air to overcome losses load (~ 1.1 Bar absoluj circulates in ~ compartment A, the entry being made by the end piece (15), the exit by the end piece (15 '). The plates (8) and (9j are respectively connected to the - and + terminals of a direct current generator capable of delivering a voltage of around 1 V between these plates. The plate (8d dis-o tributes the current on the electrode (2d along the folds which are adjacent and thanks to the conductive intermediate layers (14) internal to compartment A.
Likewise the plate (9d distributes the current on the electrode (3) along the folds which are adjacent to it and graceful to the layers lS conductive inserts (4) internal to compartment B.
The oxygen in the air circulating in compartment A is reduced to superoxide anions at the level of the electrode sheet (2) (cathode). Nitrogen, which does not undergo any electrochemical reaction mique is purged continuously by the outlet 15 'where we obtains oxygen-depleted air.
The superoxide anions which have migrated through the membrane (lj are oxidized at the anode (3) producing oxygen which is released in gaseous form in the compartment B and can be collected at one of the exits (16) or (16 ').
Such rodule ~ can be easily assembled in series or in parallel according to the characteristics of the generator of cou-rant which is being distributed.
EXAMPLE 7 Application of the device of Example 3 as a gauge -~ oxygen.
A device of the type of that according to the example is used 3 containing as electrolyte POE / POP / THAP / TBA02 ~ reason for 4/2/1/3 parts by weight.
We operate at 20 ~ C on discs of membranes of 3 cm2 surface and about 150 micron3 thick. The membrane thus made ~ ee ~ t lightly pre ~ sée between two cloth discs of conductive carbon of the type of that comm ~ specialized ~ ar la Société Carbone Lorraine under the ~ ~ c ~ / TCS 80 (or 3 ~ ~ 276; S1 ~ 4 ~
TCM 128) or that marketed by the International Company Paper. The carbon discs are themselves held in place by two stainless steel grids spray coated with gold cathodic, thin, which are connected to the measuring circuit (volt-digital meter).
This device is sensitive to any difference in chemical potential.
that, (in the present case of partial pressure of oxygen ~ nej, between the upstream and downstream media separated by the membrane, and provides a potential difference across the electrodes. We have cons-lo tate the appearance of a potential difference of 39 plus or minus 1 mV when the upstream medium consists of oxygen pure at a pressure of 1 bar, while the downstream medium is consisting of a mixture of nitrogen t78.91 ~) and oxygen (21.09 ~) under 1 bar of total pressure. The value of this difference of potential is very close to the theoretical value of 39.3 mV cal-abutment according to Nernst's Law for a monoelectronic transfer.
As a result, a reduction in oxygen is observed in ~ 2 high pressure side and oxidation of d'2 to ~ 2 on the side low membrane pressure. We get 90 ~ O of the answer in less than 10 seconds when switching from air to pure oxygen.
The experiment is commonly performed by maintaining one sides of the membrane under sweeping pure oxygen while the other side is alternately oxygen scanned pure and another gas whose oxygen content is to be measured.
~ ~ 7 ~ r, ~~~ 0 ~ / ~ c'-7rn ~ 7th, ~ c ~

Claims (46)

The realizations of the invention, about of which an exclusive right of ownership or privilege is claimed, are defined as it follows: 1. Solid compositions based on superoxides characterized in that they include:
- a material inert towards superoxide anions O2 -, playing the role of matrix with regard to these anions, - superoxide O2 anions -, these compositions forming a stable material, up to a temperature not exceeding about 100 ° C, the matrix allowing the mobility of O2- ions in this temperature range-ture. 2. Compositions according to claim 1, characterized in that they contain the anions O2- in the absence of any potential applied, to a concentration of at least about 10-2 milliequivalent per gram including at least about 1 to 2 milli-equivalents per gram. 3. Compositions according to claim 1, characterized in that they are in the form of membrane whose thickness is preferably less than less than around 500 µ, advantageously of the order of 10 to 500 µ, preferably around 30 to 100 µ. 4. Compositions according to any one of Claims 1 to 3, characterized in that they contain superoxide salts C + O2-, C + represented smelling a mineral cation, in particular, of metal monovalent, more particularly of alkali metal such as Na +, K +, Rb + and Cs + or transition metal under form of complex. 5. Compositions according to claim 1, characterized in that they contain salts of superoxide C + O2-, C + representing one or more organic cations, in particular, a cation quaternary ammonium, more especially tetraalkyl-quaternary ammonium NR4 + where R represents a radical alkyl of 1 to 10 carbon atoms approximately, preferably TMA +, TBA + or THA +. 6. Compositions according to claim 5, characterized in that the alkyl groups of tetraalkylammonium cations are substituted with ether groups for example by groups of structure [- (CH2) 2 -O] n -CH3 in which n is a whole, preferably from 1 to 5 approximately. 7. Compositions according to claim 1, characterized in that the matrix is based on a macromolecular material. 8. Compositions according to claim 7, characterized in that the macromolecular material is based on an at least partial polymer material-ment amorphous at processing temperatures, having a high dielectric constant and forming with superoxide a phase whose temperature of glass transition Tg is about 50 ° C lower at the processing temperature. 9. Compositions according to claim 8, characterized in that the polymer material is neutral or charged, more particularly comprising a majority of cationic sites, and is formed by a single type of polymer or copolymer, or contains a mixture of several polymers and / or copolymers. 10. Compositions according to claim 9, characterized in that the polymeric material comprises alkylene polyoxides, polyamides, poly-phosphazenes or polyalkyleneimines. 11. Compositions according to claim 10, characterized in that the alkylene polyoxides include propylene polyoxide (POP) and polyethylene oxide (POE). 12. Compositions according to claim 10, characterized in that the polyphosphazenes com-take ether groups and satisfy more specially to a formula of the type in which R and R 'represent hydro-saturated carbonaceous, optionally comprising one or several heteroatoms preferably O and N, possibly-lnely associated with aromatic groups, and n is the number of units in the polymer. 13. Compositions according to claim 10, characterized in that the polyphosphazenes include groups carrying functions secondary amine, tertiary amine or ammonium quater-alone or in combination and satisfy more specially to formulas of the type or in which R, R ', R1, R2, R3, R4 and R5 are defined in the same way as R and R 'in the claim cation 12. 14. Compositions according to claim 10, characterized in that the polyamides include type patterns in which R and R 'are such that defined in claim 12. 15. Compositions according to claim 10, characterized in that the polyalkyleneimines include in particular polyethyleneimines substituted comprising motifs of the type R being as defined in claim 12. 16. Compositions according to any one of claims 9 to 11, characterized in that the polymers have side chains of tution, it being understood that these retain the inertness towards O2- of the matrix, in particularly perfluoroalkyl chains. 17. Compositions according to claim 9, characterized in that the polymer material comprises grafted sites, loaded or not, allowing the transient solvation of O2 -, such as groups constituted by the patterns of the polymers according to the claim 10, pyridyl groups, or alternatively sulfonamide type GOLD
-SNR 'R and R' being as defined in claim 12. 18. Compositions according to claim 9, characterized in that the polymeric material comprises one or more anion exchange resins, preferably one or more quater ammonium resins nary, including reasons such as:
in which R and R 'represent hydro-saturated carbonaceous, optionally comprising one or several heteroatoms preferably O and N, even tally associated with aromatic groups, and n is the number of units in the polymer, the anions resin chosen in particular from anions fluoride, chloride, hydroxide, iodide, tetraphenyl-borate, carbonate or acetate, having been previously exchanged, in whole or in part, by O2- anions. 19. Compositions according to claim 18, characterized in that the resin is a homo or copo-ionic lymer produced from an ammonium monomer vinyl or allylic quaternary, alone or in copoly-mother with other quaternary ammonium monomers different allyl or vinyl. 20. Compositions according to claim 7, characterized in that they further comprise minus an additive capable, in particular, of increasing the ionic conductivity of the matrix material, chosen in particular in the group comprising a / polymers more especially of the defined type in claim 9, b / plasticizing agents, such as plasticizers polar, like cyan compounds, in particular, a compound containing these groups of the 2,4,6- type trimethoxybenzonitrile, or c / salts, in particular of the A-NR4 + type in which:
A- is an anion such as C104-, B (C6H5) 4-, Cn, F2n '+ 1 SO3- R being as defined in claim 12, and n 'is an integer from 1 to 10 approximately, or d / neutral additives, in particular compounds having a pyridine nucleus such as 2,2'-bi-pyridine. 21. Compositions according to claim 7, characterized in that the polymer material is pre-smells in cross-linked or grid form;
comprising in particular a frame formed from a other polymer or copolymer inert towards ions O2-. 22. Compositions according to claim 1, characterized in that the matrix containing the ions O2- is the association of a liquid, possibly gelled, and a support constituted by a material solid allowing percolation of O2- ions. 23. Compositions according to claim 22, characterized in that they include supports preferably thin, for example, based on glass or ceramic, such as agglomerated glass fibers, sintered glass or porous glass, or based on polymer wettable, porous or swellable with a solution impregnation, this polymer being chemically inert vis-à-vis the constituents of the solution. 24. Compositions according to claim 21, characterized in that the supported liquid is a salt molten superoxide or concentrated solution in a compatible solvent. 25. Process for the preparation of the compositions according to claim 1, characterized in that it includes incorporating O2- anions into a matrix as defined in claim 1, this incorporation being carried out chemically in presence of a solvent in which the matrix and the superoxide are soluble or can be made soluble using additives, or electronically chemical, in which the accumulation is carried out of O2- anions in an electrolytic matrix by replacement of other pre-active electroactive anions existing in the matrix, these being eliminated by anodic oxidation as it is created of O2- ions at a cathode subjected to a flow of oxygen gaseous or dissolved. 26. The method of claim 25, charac-terized in that to prepare the compositions of superoxides in membrane form, we proceed to evaporation of the solvent (s) from a mixture consisting, on the one hand, of a solution of the material constituting the matrix and, on the other hand, of a solution of the superoxide salt, these solutions being degassed, and then the membrane formed is preferably dried.
under inert gas flow at temperature controlled and advantageously an annealing of preferably at a temperature close to the melting of matrix material as far as superoxide is not degraded at this temperature. 27. Process for the preparation of superoxides of quaternary ammonium used in the process according to claim 25, characterized in that reacts, in an organic solvent medium, in particular in pyridine a / a quaternary ammonium salt whose inert anion vis-à-vis O2- is preferably chosen from among anions F-, I-, OH-, NO3-, ClO4, BPh4-, CH3COO-, CO3--b / an excess of superoxide of which the cation is a alkali metal cation preferably K + or a cation quaternary ammonium, preferably TMA +. 28. Electrolytic materials, characterized in what they are based on superoxide compositions according to claim 1. 29. Materials according to claim 28, charac-terized in that they further comprise electronic conductive cells such as particles carbon or Fe3O4 magnetules, these particles being in sufficient concentration to confer to said materials an electronic conductivity at the operating temperature. 30. Materials according to claim 28, charac-terized in that they contain a polymeric material, in particular, an alkylene polyoxide such as propylene polyoxide (POP) and polyoxide ethylene (POE). 31. Materials according to claim 30, character-laughed at in that they include a copolymer, plus specially a random copolymer with units OE and OP, advantageously at least 5% of OP, preferably approximately 40%, the molecular weight of the copolymer being of the order of 5000 to 500,000. 32. Materials according to claim 28, charac-in the form of membranes comprising a mixture of polymers and one or more several additives, in particular a mixture of polymers / additives / superoxide, in proportions by weight of approximately 6/1/2, the mixture of polymers being in particular based on POE, and another polymer such as POP, preferably according to a ratio of 4/2. 33. Materials according to claim 32, charac-terized in that the membranes include [POE / POP /
additive such as THAP / superoxide such as TBAO2], depending on the weight proportions of approximately [3 to 5/2/1/2] or again [POE / POP / additive such as THAP / superoxide mineral such as KO2 / complexing agent such as ether crown 18-crown-6] according to the proportions by weight [3 to 5/2/1 / 0.4 / 0.4]. 34. Electrochemical transfer cells oxygen characterized in that they involve, as selective oxygen and current carriers, O2- ions moving within a matrix of electrolytic material according to claim 28. 35. Electrochemical cells as claimed cation 34, characterized in that they include the electrolytic material, advantageously in the form of membrane, confined between two coextensive electrodes face to face with said film, these electrodes being made of a conductive material permeable to agaz, inert towards the electrolytic material to temperature below 100 ° C and at least stainless as regards the anode, this material being identical tick or different for the two electrodes. 36. Electrochemical cells as claimed cation 35, characterized in that the materials are carbon-based. 37. Electrochemical cells as claimed cation 35, characterized in that at least one of electrodes is formed from a combination of materials, in particular, a tramp of a polymer provided with properties of high resistance, supporting a very thin film thin electronic conductive polymer itself loaded with glassy carbon powder or some other product providing good electronic transfer, or still one or more materials giving them conduction properties both electronic and ionic with respect to O2-. 38. Electrochemical cells according to one any of claims 34 to 36 characterized in what they include a mixed electro- conductor ionic and ionic, interposed between the electrode and the electrolyte, in which O2 is soluble. 39. Electrochemical cells according to one any of claims 34 to 36 characterized in that they are in the form of small modules from a few dozen to a few hundred m2 each, in particular of cylindrical modules where the membrane is wound in a spiral, of the type used read in conventional gas permeation, or modules including accordion-folded membranes in a housing, these modules being mounted in series, in parallel or in parallel series. 40. Process for the selective transfer of oxygen from a first medium to a second medium, characterized in that that we implement electrochemical reduction oxygen leading to transient ion formation O2 -, the diffusion of oxygen in the form O2- in a electrolytic material according to claim 28 ce material constituting a practically complete barrier highly impermeable to gases, and oxidation to oxygen O2- ions. 41. Method according to claim 40, charac-terrified in that we impose a potential difference, using an external electric generator, terminals of the electrodes of a cell as defined in any of claims 34 or 35 separating the first and second media. 42. The method of claim 40, character-laughed at using an electrochemical cell according to any of claims 34 or 35 in which the two electrodes are connected by a passive outdoor circuit with switch and a variable resistance system that we maintain between the two faces of the electrolytic material of the cell a partial pressure difference of oxy-gene, which helps regulate or stop the oxygen flow transferred from the pressure medium partial high oxygen in the middle of pressure partial lower. 43. Process for the selective transfer of oxygen from a first gaseous medium at partial pressure of oxygen so-called high towards a second pressure medium partial weaker oxygen, characterized in that we control a partial pressure difference of oxygen between said media separated by a membrane comprising a material according to claim 29. 44. Partial pressure measurement method oxygen in a gas, characterized by measuring a difference in electrical potential appearing at electrode terminals of an electrochemical cell according to any one of claims 34 or 35 and separating two media, maintaining pressure partial reference oxygen in a first medium adjacent to an electrode and gas inlet at partial pressure of oxygen to be measured in the second medium adjacent to the other electrode. 45. Process for the selective transfer of oxygen from a first gaseous medium at partial pressure of oxygen said to be high in a second medium at partial pressure of lower oxygen, characterized in that maintains a partial pressure difference between the environments considered separated by a cell electrochemical according to any one of the claims cations 34 to 36 and that the electrical voltage generated across the electrodes is used as a source of electrical energy. 46. Process for selective oxygen transfer according to claim 40, applied to the separation oxygen, in particular for the production of oxygen by concentration from air, for industry or in the medical field, gas purification containing oxygen and the introduction of controlled amounts of oxygen in a gas.