EP3782213A1 - Lithium/sulfur battery with increased capacity and associated production process - Google Patents

Abstract

The invention relates to a battery comprising an anode, a separator, a cathode comprising a composite material based on sulfur and on carbon-containing material, and a catholyte comprising at least one organosulfur species contributing to the capacity of the cathode. The invention also relates to a process for producing such a battery.

Description

 LITHIUM / SULFUR BATTERY WITH INCREASED CAPACITY AND METHOD OF MANUFACTURING THE SAME

The present invention relates to the field of batteries and more specifically sulfur-based batteries with high energy and power densities. In particular, the present invention relates to a battery comprising a composite material comprising sulfur and carbon having improved performance. The invention also relates to a method for preparing such a battery.

PRIOR ART [0002] The development of rechargeable high energy density batteries is of great technological and commercial interest. Such batteries already equip portable electronic systems (e.g., Li-ion batteries) or hybrid cars (e.g., Ni-MH batteries). However, due to increasing energy demand for electronic, networked transport and storage applications, the need is growing for batteries with increasingly large storage and discharge capacities.

[0003] Sulfur-based storage batteries, such as lithium / sulfur (Li / S) storage batteries or Li / S batteries, are seen as promising alternatives to Li-ion batteries. In addition, sodium-sulfur batteries have high storage capacities and are mainly used to support renewable energy sources. Indeed, sulfur has the advantages of being abundant, lightweight, low cost and non-toxic, which allows to consider the development of large-scale sulfur-based batteries. In addition, the interest for this type of battery comes in particular from the high potential energy density of sulfur. Indeed, the electrochemical conversion of elemental sulfur to sulphide ion (S ² ) offers a theoretical capacity of 1675 mAh / g compared to less than 300 mAh / g for a conventional Li-ion cell cathode.

However, the development of conventional Li-S batteries continue to suffer from a decrease in capacity relatively fast cycling. Thus, the Applicant has proposed adding an organosulfur component comprising a bond -SS _n -, where n is greater than or equal to 1, in the electrolyte, in the cathode or in the separator so as to prevent the formation of insoluble species. of lithium sulphide (eg LiS and US2) reducing their deposition in battery cells and the loss of reactive species during charge / discharge cycles repeated. This allowed to observe a good stability to the cycling of the battery (CN106058229). In addition, it has been proposed to modify the functionalities of these organosulfur species in order to control their distribution in the cathode / catholyte. However, the proposed batteries having such characteristics have a capacity of the order of 200 mAh / g (WO2013155038) or 400 W / kg (EP0739544).

[0005] Sulfur is a very attractive cathode active material for its very high theoretical specific capacity of 1672 mAh / g, which is very much higher than any conventional active material. But its major disadvantage is the low electronic and ionic conductivity of sulfur. Usually, the formulation of the sulfur-based cathode additionally contains sulfur a carbon-based electrical conductor and much of the state of the art on Li-S battery architecture is dedicated to optimizing the ratio Sulfur - Carbon within the cathode or the use of other forms of carbon such as carbon nanotubes (CNTs).

NTCs are difficult to handle and disperse, because of their small size, their powderiness and, possibly, when they are obtained by chemical vapor deposition, their entangled structure generating strong interactions of Van Der Waals between their molecules. The mixture of the active ingredient and the conductive additive can be done in different ways. It has been proposed by the Applicant a Sulfur-Carbon composite, more particularly Sulfur-NTC, formed by molten way making the cathode more conductive (WO2016066944). This is an approach to reduce the amount of carbon charge required for the operation of the cathode, so to increase the rate of sulfur in the cathode. Nevertheless, batteries based on such an active material have capacities of the order of 1250 mAh / g at a C / 10 regime still below the theoretical capacity of sulfur of 1672 mAh / g (WO2016102942).

In addition, it has been proposed electrochemical cells comprising organosulfur species capable of improving the performance of such electrochemical cells during repeated cycles of discharge and charging batteries (US2017 / 084953) others have furthermore shown. an increase in capacity (US2014 / 1 70459 and Shuru Chen et al., 2016, Angew Chem Int.Ed 2016, 55, 4231-4235).

Thus, despite the improvements in cycling stability obtained with the methods of the prior art, there is a need for batteries having a high capacity and increased cycling speed. rTechnical problem!

The invention therefore aims to overcome the disadvantages of the prior art. In particular, the object of the invention is to propose a Sulfur-based battery having an improved capacitance. The invention also aims to propose a sulfur-based battery with faster cycling.

The invention further aims to provide a method for preparing such a battery, said method being fast and simple to implement.

Brief description of the invention

[001 1] The present invention relates to a battery comprising an anode, a separator, a cathode comprising a composite material based on sulfur and carbon material, and a catholyte, characterized in that the catholyte comprises at least one participating organosulfur species to the capacity of the cathode and preferably in that the composite material has been formed in the melt.

As will be presented later, the battery according to the invention has a specific capacity greater than the specific capacity observed for sulfur-based batteries. Indeed, the Li-S batteries of the prior art have initial discharge capacities lower than 1670 mAh / g with the majority of initial discharge capacities of the order of 1000 mAh / g, while the battery according to the invention has an initial discharge capacity generally greater than 1800 mAh / g. In addition, as will be presented, the battery according to the invention can do without the training step generally essential to the operation of the battery.

[0013] According to other advantageous characteristics of the battery:

the anode comprises an active anode material comprising sodium or lithium. Preferably, the anode may comprise lithium. Indeed, a lithium-sulfur battery according to the invention achieves unequaled discharging capabilities.

the composite material has been formed in the melt, for example through a step of melting the sulfur and kneading the sulfur and the carbonaceous material. Use a melt-formed composite permits intimate mixing of the sulfur and the carbonaceous material so as to improve the performance of the battery.

the carbonaceous material is selected from: carbon black, carbon nanotubes, carbon fibers, graphene, acetylene black, graphite, carbon nanofibers and a mixture of these in all proportions. Preferably, the carbonaceous material is selected from: carbon nanotubes, carbon nanofibers, graphene, and a mixture thereof in all proportions.

the composite material comprises sulfur in the elemental state.

the composite material furthermore comprises selenium. Indeed, the presence of selenium, preferably in low concentration, protects the cathode

the at least one organosulfur species is selected from: an organic disulfide, an organic polysulfide, a thiol, a polythiol, a thiolate or a polythiolate.

- the at least one organosoufrée species is selected among compounds of following formulas: RS R _X, R (SH) _n, R (SM) _X, R (COSH) _n, R (COSM) _n, R _x and RCOS polymer having one or more functions -S _x -, -COS _x -, -SH, -SM, -COSH, -COSM,

With:

 M selected from Li and Na;

 R selected from substituted or unsubstituted alkyl or aryl groups, x an integer greater than or equal to 2,

 n an integer greater than or equal to 1.

the catholyte further comprises:

one or more alkali metal salts, such as ATFSi, AFSi, ANO ₃ , ATDI, ACF ₃ SO ₃ ,

- inorganic and organic polysulfides salts A _{Z X} S and RS _X A, or

 - their mixtures,

 with R selected from substituted or unsubstituted alkyl or aryl groups,

 Selected from Li, Na, K, Rb or Cs,

 x an integer greater than or equal to 2, and

z an integer greater than or equal to 2. the catholyte further comprises one or more lithium salts, such as LiTFSi, LiFSi, LiTDI, UNO ₃ , LiCF ₃ SO ₃ , and mixtures thereof, and the Li: RS _y Li polysulfides with y an integer greater than or equal to 2; and R selected from substituted or unsubstituted alkyl or aryl groups.

the catholyte may also comprise a polymeric binder.

the at least one organosulfur species is a polymer and is capable of behaving like a polymeric binder.

the at least one organosulfur species acting as a polymeric binder is selected from a polymer containing the following functions: disulfide -SS-, polysulfides -S _n - with n an integer greater than or equal to 2, and / or -SH. The organosulfur species may then for example be selected from: polyethylene sulfide, polydisulphide, polyphenylsulfide, poly (1,8-Dimercapto-3,6-dioxaoctane), and / or polysulfideDMDO. The disulfide -SH-, polysulfide-S _{n- functions} with n an integer greater than or equal to 2 are preferably carried by the main chain of the polymer while the -SH functions are preferably on the side chains.

the organosulfur species or species participating in the capacity of the cathode are present in the catholyte at a concentration greater than or equal to 0.05 mol / l. Preferably, the organosulfur species or species participating in the capacity of the cathode are present in the catholyte at a concentration greater than or equal to 0.1 mol / l, more preferably greater than or equal to 0.2 mol / l and even more preferred way greater than or equal to 0.25 mol / L

it comprises mineral sulfur and organic sulfur and in that the molar ratio between the inorganic sulfur and the organic sulfur is between 0.05 and 10 and preferably between 0.1 and 7.

the cathode has a specific theoretical capacity greater than 1700 mAh / g

the cathode has a specific capacity greater than 1300 mAh / g measured at a discharge rate equal to C / 10. Preferably, the cathode has a specific capacity greater than or equal to 1500 mAh / g measured at a discharge rate equal to C / 10 and more preferably greater than or equal to 200 mAh / g. This value is for example measured at 25 ° C. the cathode has a specific capacity greater than 500 mAh / g measured at a discharge rate equal to C / 1. Preferably, the cathode has a specific capacity greater than or equal to 800 mAh / g measured at a discharge rate equal to C / 1 and more preferably greater than or equal to 1700 mAh / g and more preferably greater than or equal to 2000 mAh / g. This value is for example measured at 25 ° C.

- The cathode is capable of having a specific capacity greater than 1000 mAh / g measured at a discharge rate equal to C / 1 after 400 cycles. This value is for example measured at 25 ° C. the battery does not require a training step.

According to another aspect, the invention further relates to a method of manufacturing a battery according to the invention characterized in that it comprises:

a step of preparing a catholyte comprising at least one organosulfur species participating in the capacity of the cathode and

 a step of assembling an anode, a cathode, a separator and the catholyte.

According to other advantageous features, the manufacturing method according to the invention does not include a step of forming the battery after the assembly step.

Other advantages and features of the invention will become apparent on reading the following description given by way of illustrative and nonlimiting example, with reference to the appended figures which represent:

FIG. 1, a schematic representation of a battery according to the invention;

 • Figure 2, a schematic representation of steps implemented according to the invention during the process for preparing a composite material used in the invention. Dotted steps are optional;

FIG. 3, a galvanostatic C / 10 charge / discharge profile having the initial discharge capacity in the absence of an organosulfur species (the dashed line) and in the presence of 0.4 M DMDO (line curve). full); • Figure 4, a galvanostatic profile of charge / discharge; at C / 10 for cycles 1 and 20 in the presence of 0.2 M DMDO;

 FIG. 5, an aging curve of a Li-S battery comprising the organosulfur diphenyldisulfide species at 0.2 M, illustrating the discharge capacity (solid squares) and the efficiency (open circles) at a C regime.

[Description of the invention

In the remainder of the description, the term "catholyte" designates an electrolyte that can participate in the discharge capacity by its reversible reduction to the load and may in particular comprise the components of an active material which form a cathode.

By "polymer binder" is meant a polymer which in combination with a salt can form a polymer electrolyte. The polymeric binder may be capable of forming a solid polymer electrolyte or gelled polymer electrolyte.

The term "solvent" a substance, liquid or supercritical at its temperature of use, which has the property of dissolving, diluting or extracting other substances without chemically modifying them and without itself itself change . "Liquid phase solvent" is a solvent in the liquid state.

By "Sulfur-Carbon Composite" is meant an assembly of at least two immiscible components whose properties are complementary, said immiscible components comprising a sulfur-containing material and a carbon nanocharge. By "sulfur-containing material" is meant a sulfur-donor compound, for example chosen from vulcanizing agents and preferably selected from native sulfur (or in the elemental state), sulfur-containing organic compounds including polymers, and compounds inorganic sulfur. Preferably the sulfurized material is sulfur in the elemental state.

"Sulfur in the elemental state" means sulfur particles in a crystalline form Se or in an amorphous form. More particularly, this corresponds to elemental sulfur particles having no sulfur associated with carbon from the carbon nanofillers.

In the present invention, the expression "carbonaceous material" means a material essentially comprising carbon, that is to say comprising at least 80% by weight about carbon, preferably at least about 90% by weight carbon, and more preferably at least about 95% by weight carbon.

By "carbon nanobond" is meant a charge comprising at least one member of the group consisting of carbon nanotubes, carbon nanofibres and graphene, or a mixture thereof in all proportions. Preferably, the carbon nanofillers comprise at least carbon nanotubes. The term "nanofiller" is usually used to denote a carbonaceous filler whose smallest dimension is between 0.1 and 200 nm, preferably between 0.1 and 160 nm, more preferably between 0.1 and 50 nm, measured by diffusion. light.

By "compounding device" is meant, according to the invention, an apparatus conventionally used in the plastics industry, for the melt blending of thermoplastic polymers and additives in order to produce composites. In this apparatus, the sulfur-containing material and the carbon nanofillers are mixed using a high-shear device, for example a co-rotating twin-screw extruder or a co-kneader. The melt generally comes out of the apparatus in an agglomerated solid physical form, for example in the form of granules.

By "polymer" is meant either a copolymer or a homopolymer. The term "copolymer" means a polymer comprising several different monomer units and "homopolymer" means a polymer comprising identical monomeric units. The term "block copolymer" means a polymer comprising one or more uninterrupted sequences of each of the different polymeric species, the polymer blocks being chemically different from one another and being linked together by a covalent bond. These polymer blocks are still referred to as polymer blocks.

The term "radical initiator", within the meaning of the invention, denotes a compound that can start / initiate the polymerization of a monomer or monomers.

The term "polymerization", within the meaning of the invention, refers to the process for converting a monomer or a mixture of monomers into a polymer.

The term "monomer", within the meaning of the invention, denotes a molecule that can undergo polymerization.

The expression "group consisting of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated" as used in the present invention, corresponds to a saturated hydrocarbon chain, linear, cyclic or branched, containing 1 at 20 carbon atoms or a linear, cyclic or branched unsaturated hydrocarbon chain containing from 2 to 20 carbon atoms. A linear, cyclic or branched saturated hydrocarbon chain containing from 1 to 20 carbon atoms includes, but is not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl and the like. butyl, n-pentyl and the like. A linear or branched, unsaturated hydrocarbon chain containing from 2 to 20 carbon atoms comprises at least one double or triple bond, and includes, but is not limited to, ethenyl, propenyl, butenyl, pentenyl, ethynyl, propynyl, butynyl, pentynyl and the like.

The term "(C1-C12) alkyl", as used in the present invention, denotes a saturated, linear or branched alkyl group having between 1 and 12 carbon atoms, substituted or unsubstituted, which may comprise at least a heteroatom such as N, or O for example.

The term "(C2-C12) alkenyl", as used in the present invention, denotes an unsaturated, linear, branched or cyclic alkyl group having between 2 and 12 carbon atoms and at least one double bond, substituted. or unsubstituted, which may comprise at least one heteroatom such as N, or O, for example.

The term "(C2-C12) alkynyl", as used in the present invention, denotes a linear, branched or cyclic unsaturated alkyl group having between 2 and 12 carbon atoms and at least one triple bond, substituted. or unsubstituted, which may comprise at least one heteroatom such as N, or O, for example.

The term "cycloalkyl" as used in the present invention refers to a substituted or unsubstituted cyclic saturated alkyl group which may comprise at least one heteroatom such as N, or O, for example.

The term "aryl", as used in the present invention, denotes an aromatic hydrocarbon group preferably comprising 6 to 10 carbon atoms and comprising one or more, in particular 1 or 2, condensed rings, for example a phenyl group or a naphthyl group. Advantageously, this designates a phenyl group.

The term "heteroaryl" as used in the present invention refers to a mono-, bi- or tri-cyclic aromatic radical containing a total of 3 to 13 atoms, of which 1, 2, 3 or 4 are chosen independently of one another from nitrogen, oxygen and sulfur, optionally in the oxidized state (case of nitrogen and sulfur), the other atoms being carbon atoms, the said heteroaryl radical being optionally substituted by one or more chemical species, identical or different. The term "alkylaryl", as used in the present invention, refers to an aryl group as defined above bonded to the molecule via an alkyl group. In particular, the term "- (C1-C12 alkyl) -aryl", as used in the present invention, refers to an aryl group as defined above bonded to the molecule via a C1-C12 alkyl group such as as defined above. In particular, the - (C 1 -C 12 alkyl) aryl group according to the invention is a propane-phenyl group. The term "arylalkyl" as used in the present invention refers to an aryl group as defined above, substituted with an alkyl group and attached to the molecule via the aryl group. This corresponds for example to a benzyl.

For groups comprising two or more subgroups, the attachment is indicated by "-". For example, "- (C1-C5) alkyl-aryl" means an alkyl radical bonded to an aryl radical in which the alkyl is bonded to the rest of the molecule. For groups comprising an attachment on each side, for example, "- (C 1 -C 5 alkyl) -aryl-", this refers to an alkyl radical attached to an aryl radical in which the alkyl or aryl are bonded to the remainder. of the molecule and this encompasses both a - (C 1 -C 5) alkyl-aryl-group and a -aryl- (C 1 -C 5 -alkyl) - group.

The groups according to the invention, for example the alkyl, alkenyl, aryl heteroaryl or cycloalkyl groups, may be optionally substituted according to the present invention with one or more groups independently selected from the group consisting of alkyl, alkoxyl (alkoxyl), hydroxyl, carboxyl, ester, thiol or thiolate. Examples of optionally substituted phenyl groups are methoxyphenyl, dimethoxyphenyl and carboxyphenyl. Alternatively, they are only substituted if explicitly specified. The term "optionally substituted" as used herein means that any of the hydrogen atoms may be replaced by a substituent, such as an alkyl, alkoxyl (alkoxyl), hydroxyl, carboxyl, ester, thiol or thiolate group. .

The invention is now described in more detail and without limitation in the description which follows. In the rest of the description, the same references are used to designate the same elements.

 As shown in the examples, the inventors have developed a new generation of sulfur-based battery whose cathode has an improved capacity.

Indeed, while lithium-sulfur batteries developed in recent years are generally limited to capacities less than 1300 mAh.g ^-1 (see Table 1), the battery according to the invention can achieve in some embodiments a capacity greater than 2000 mAh.g- ¹ .

 For this, the inventors have developed a battery whose catholyte has an organosulfur species participating in the capacity of the cathode. As will be detailed later, the presence of the organosoufrée species makes it possible to increase the capacity of the cathode to levels hitherto unequaled.

In addition, the organosulfur species makes it possible to eliminate the tedious step of 1 ^st charge and discharge.

Battery

 Thus, according to a first aspect, the invention relates to a battery comprising an anode 10, a separator 20, a cathode 30 comprising a composite material based on sulfur and carbon material, and a catholyte 40 comprising at least one Organosulfur species participating in the cathode capacity. Such a battery is shown in FIG.

 The battery according to the invention is more particularly a rechargeable battery.

The catholyte

At 25 ° C, the catholyte can be liquid, gelled or solid. The state of the catholyte at 25 ° C may be predetermined and will depend on the specifications of the battery incorporating said catholyte.

As mentioned, the battery according to the invention may in particular be characterized in that the catholyte comprises at least one organosulfur species participating in the capacity of the cathode.

In particular, the catholyte comprises at least one organosulfur species participating in the capacity of the cathode at a concentration greater than or equal to 0.05 mol / L, preferably greater than or equal to 0.1 mol / L, of more preferably greater than or equal to 0.2 mol / L and even more preferably greater than or equal to 0.25 mol / L.

For example, the catholyte comprises at least one organosulfur species participating in the capacity of the cathode at a concentration of between 0.05 and 1 mol / L, preferably between 0.1 and 0.6 mol / L, more preferably between 0.2 and 0.5 mol / L and even more preferably between 0.25 and 0.45 mol / L. The terminals are included. As will be detailed later, the organosulfur species participating in the capacity of the cathode may comprise several functions capable of improving the capacity of the cathode, for example at least one reactive function of the -S-Sn- type or of type -SH or -SM, with n ranging from 1 to 5, and M possibly being sodium, lithium, ammonium, sulfonium or quaternary phosphonium.

Thus, in particular, the catholyte comprises at least one organosulfur species participating in the capacity of the cathode at a concentration such that the reactive functional concentration -S-Sn- is greater than or equal to 0.05 mol / L. , preferably greater than or equal to 0.1 mol / L, more preferably greater than or equal to 0.2 mol / L and even more preferably greater than or equal to 0.25 mol / L.

For example, the catholyte comprises at least one organosulfur species participating in the capacity of the cathode at a concentration such that the concentration of reactive function - S-Sn- is between 0.05 and 1 mol / L, so that preferred between 0.1 and 0.6 mol / L, more preferably between 0.2 and 0.5 mol / L and even more preferably between 0.25 and 0.45 mol / L. The terminals are included.

Alternatively, the catholyte comprises at least one organosulfur species participating in the capacity of the cathode at a concentration such that the reactive functional concentration -SH or -SM is greater than or equal to 0.1 mol / L, of preferred way greater than or equal to 0.2 mol / L, more preferably greater than or equal to 0.4 mol / L and even more preferably greater than or equal to 0.5 mol / L.

For example, the catholyte comprises at least one organosulfur species participating in the capacity of the cathode at a concentration such that the reactive functional concentration -SH or -SM is between 0.1 and 2 mol / L, so that preferred between 0.2 and 1.2 mol / L, more preferably between 0.4 and 1 mol / L and even more preferably between 0.5 and 0.9 mol / L; with M selected from sodium, lithium, ammonium, sulfonium or quaternary phosphonium.

As will be shown in the examples, the inventors have determined particularly advantageous ratios between the amount of organic sulfur and the amount of inorganic sulfur in the cathode / catholyte assembly or the total amount of sulfur in the cathode / cathode assembly. catholyte. The amount of inorganic sulfur may in particular correspond to elemental sulfur present in the cathode and more particularly in the composite material. Nevertheless, the mineral sulfur may also include elemental sulfur that would have been added to the catholyte.

The amount of organic sulfur may correspond more particularly to the amount of sulfur present in the organosulfur species participating in the capacity of the cathode. The sulfur present in the organosulfur species participating in the capacity of the cathode is that found in the catholyte but may also include that which could be present in the cathode and / or the separator.

The amount of total sulfur corresponds to the mineral sulfur as well as the sulfur present in the organosulfur species participating in the capacity of the cathode.

The inorganic sulfur and organic sulfur present in the organosulfur species participating in the capacity of the cathode can for example be quantified by: high performance liquid chromatography, X-ray crystallography, X-ray absorption spectrometry , Raman Spectroscopy, Infrared Spectroscopy, UV-Vis Spectroscopy, Differential Scanning Calorimetry or Mass Spectrometry (eg ICP-MS or ICP-MS-MS).

Advantageously, the molar ratio of inorganic sulfur / organic sulfur is between 0.05 and 10, preferably between 0.1 and 7. Even more preferably, the ratio of mineral sulfur / organic sulfur is substantially equal. In particular, the molar ratio of mineral sulfur / sulfur present in the organosulfur species participating in the capacity of the cathode is between 0.05 and 10, preferably between 0.1 and 7. Even more preferably , the molar ratio of mineral sulfur / sulfur present in the organosulfur species participating in the capacity of the cathode is substantially equal to 5.

The organosoufrée species

The organosulfur species is preferably selected from: an organic disulfide, an organic polysulfide, a thiol (i.e. mercaptan), a polythiol, a thiolate (i.e. mercaptide) or a polythiolate. In addition, it may take the form of an oligomer or a polymer.

These compounds may have one or more SS bonds that can be broken during the discharge cycle of a lithium-sulfur battery and reformed during the charge cycle. Similarly thiol and thiolate functions can lead, during the charging cycle, SS bond formation.

The organosulfur species may in particular correspond to a compound according to formula I:

in which :

 - X = -H, -M or -A;

 M is selected from sodium, lithium, ammonium, sulfonium or quaternary phosphonium;

- A = -S _n -R1'-L ';

 The groups R 1 and RL are identical or different and represent a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or several heteroatoms;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO-, -COS-, -CSS-, -O-, -CONR5-, hydrogen, - (Ci-Ci2) alkyl, - (C2- Ci2) alkenyl, - (C2-Ci2) alkynyl, -F, -CF _3, -NH ₂ , -NO ₂ , -SO ₂ H, -SH, -COOR 5, -COR 5, -SCOR 5, -CSSR 5, and -OR 5; if L has a free connection then it allows to connect L to RL or to L 'and if L' has a free connection then it makes it possible to connect L 'to Ri or to L;

 the group R5 represents a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl;

 - n is an integer between 1 and 5, the terminals are included; and

 p is an integer between 1 and 10.

For example, when p is greater than or equal to 2, the organosulfur species participating in the capacity of the cathode may correspond to the following compounds:

The syntheses of these compounds are known and are commercially available, for example under the name Thiocure® (trade name). In this context, the organosulfur species participating in the cathode capacity may particularly be selected from: Thiocure® GDMP (1a), Thiocure® TMPMP (Ib), Thiocure® Di-PETMP (on), Thiocure® ETTMP (Id), Thiocure® PETMP, Thiocure® GDMA, Thiocure® TMPMA, Thiocure® PETMA , and Thiocure® TEMPIC (trade names).

When p is equal to 1, the organosulfur species may in particular correspond to a compound according to formula G:

in which :

 - X = -H, -M or -A;

 M is selected from sodium, lithium, ammonium, sulfonium or quaternary phosphonium;

- A = -S _n -RT-L ';

 The groups R 1 and RL are identical or different and represent a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or several heteroatoms;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO-, -COS-, -CSS-, -O-, -CONR5-, hydrogen, - (C1-C12) alkyl, - (C2-

Ci2) alkenyl, - (C2-Ci2) alkynyl, -F, -CF _3, -NH _2, -NO2, -SO2H, -SH, -COOR 5, -COR 5

COSR5, -CSSR5, and -OR5; if L has a free connection then it allows to connect L to RL or to L 'and if L' has a free connection then it makes it possible to connect L 'to Ri or to L;

 the group R5 represents a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl; and

 n is an integer between 1 and 5, the terminals are included.

In particular, the organosulfur species may correspond to an organic polysulfide. When the organosulfur species corresponds to an organic polysulfide such as a disulfide, then it may correspond to a compound according to formula II.

In which :

 The groups R 1 and RL are identical or different and represent a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or several heteroatoms;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO- , -COS-, -CSS-, -O-, -CONR ₅ -, hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C 12) alkenyl, - (C ₂ -C 12) alkynyl, -F, -CF ₃ , -NH ₂ , -NO ₂ , -SO ₂ H, -SH, -COOR 5, -COR 5, -SCOR 5, -CSSR 5 and -OR 5; if L has a free connection then it allows to connect L to RL or to L 'and if L' has a free connection then it makes it possible to connect L 'to Ri or to L;

the group R ₅ represents a group selected from: a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl; and

 n is an integer between 1 and 5, the terminals are included.

In particular, the organosulfur species may correspond to an organic disulfide and therefore comprise a disulfide group.

In this context, an organosulfur species of disulfide type participating in the capacity of the cathode may correspond to a compound according to formula III.

In which :

The groups R 1 and RL are identical or different and represent a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example from alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO- , -COS-, -CSS-, -O-, -CONR ₅ -, hydrogen, - (CrCi 2) alkyl, - (C 2 -C 12) alkenyl, - (C 2 -C 12) alkynyl, -F, -CF ₃ , -NH ₂ , -NO ₂ , -SO ₂ H, -SH, -COOR 5, -COR 5, -SCOR 5, -CSSR 5 and -OR 5; if L has a free connection then it allows to connect L to RL or to L 'and if L' has a free connection then it makes it possible to connect L 'to Ri or to L; and

the group R ₅ represents a group selected from: a hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl.

In particular, the groups Ri and Ri 'may respectively represent -R2-R4-R3- and -R2 -R4 -R3- in which:

- the groups R _2, R _3, R ₂ 'and R _3' are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C ₁ - Ci ₂₎ alkyl-, - (C ₂ -C ₂₎ alkényle-, - (C ₂ -C ₂₎ alkynyle-, -aryl-, -cycloalkyle-, substituted or unsubstituted;

the groups R ₄ and R ₄ 'are identical or different and represent a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- and -O-;

the group R ₅ represents a group selected from: a hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl.

Thus, preferably, the organosulfur species participating in the capacity of the cathode may correspond to symmetrical disulfide compounds with alkyl chain: dimethyl disulfide (Ilia compound), diethyl disulfide (DEDS), disulfide of dipropyl (DPDS), dibutyl disulfide (DBDS), dipentyl disulfide (or diammonium disulfide), dihexyl disulfide.

Some of these compounds as well as disulphides resulting from the oxidation of thioglycolic acid esters, such as compounds IIIc and IIId, are illustrated below:

The organosulfur species participating in the capacity of the cathode may also correspond to asymmetric disulfide compounds or mixed alkyl chain such as ethylmethyldisulphide (Nie).

In the context of the invention, asymmetric and symmetrical disulfide mixtures of different alkyl or aryl chains can be used. Thus, the organosulfur species participating in the capacity of the cathode may correspond to a mixture of organosulfur species. For example, the DSOs ("Oilsulfide Oils" in English) are mixtures of disulfides from, for example, gas or oil extraction fields and could be used in the case of the present invention. DTDDS (ditertiododecyl disulfide, IIIf) is a mixture of disulfides, the major part of which consists of carbon chain disulfides of 12 carbons.

The organosulfur species participating in the capacity of the cathode may also correspond to disulfide-type compounds resulting from the oxidation of dithiols:

The organosulfur species participating in the capacity of the cathode may also correspond to a molecule containing several disulfide units. It can thus take the form of linear molecules such as the adduct of two DMDO or cyclic molecules such as, for example, the following compounds:

In particular for the compounds (IIIll), (IIId) and (IIIk), L comprises a bond making it possible to connect L to RL or to L '.

The organosulfur species participating in the capacity of the cathode may also comprise rings and more particularly comprise aromatic rings directly linked to the S-S bond.

Thus, according to one embodiment, the organosulfur species participating in the capacity of the cathode may correspond to a compound according to formula IV.

In which:

 Re, R7, Re, Rg, R10, Re ', R7', Re ', Rg' and R10 'are the same or different and represent a group selected from: hydrogen, - (C1-C12) alkyl, - ( C2

Ci2) alkenyl, - (C2-Ci2) alkynyl, -F, -CF _3, -NH _2, -NO2, -SO2H, -SH, -COOR 5, -COR 5

COSR5, -CSSR5 and -OR5;

 the group R5 represents a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl; and

 n is an integer between 1 and 5, the terminals are included.

As will be presented in the examples, in this context, the organosulfur species participating in the capacity of the cathode may correspond to the following compounds:

The organosulfur species participating in the capacity of the cathode may also comprise one or two carbonyl or thiocarbonyl groups directly attached to a disulfide bond (S-S).

Thus, according to one embodiment, the organosulfur species participating in the capacity of the cathode may correspond to a compound according to Formula V.

 In which :

 The groups Rn and Rn 'are identical or different and represent a group composed of 1 to 19 carbons, branched or linear, unsaturated or unsaturated, for example of alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms.

 Groups G and G 'are identical or different and represent an atom

 selected from Oxygen or Sulfur;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO- , -COS-, -CSS-, -O-, -CONR ₅ -, a hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -

Ci2) alkenyl, - (C2-Ci2) alkynyl, -F, -CF _3, -NH _2, -NO2, -SO2H, -SH, -COOR 5, -COR 5

COSR5, -CSSR5 and -OR5; if L has a free connection then it allows to connect L to R 'or L' and if L 'has a free connection then it allows to connect L' to R ₁₁ or L;

the group R ₅ represents a group selected from: a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl; and

 n is an integer between 1 and 5, the terminals are included.

In particular, the groups R and R 'can respectively represent -R2-R4-R3-Ot -R2 -R4 -R3- in which:

- the groups R _2, R _3, R ₂ 'and R _3' are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C ₁ - Ci ₂₎ alkyl-, - (C ₂ -C ₁₂ ) alkenyl-, - (C ₂ -C ₁₂ ) alkynyl-, -aryl-, -cycloalkyl-, substituted or unsubstituted;

the groups R ₄ and R ₄ 'are identical or different and represent a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- and -O-; the group Rs represents a group selected from: a hydrogen, - (Ci-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl.

As will be presented in the examples, in this context, the organosulfur species participating in the capacity of the cathode may correspond to the following compounds:

As has been presented previously, many organosulfur species participating in the capacity of the cathode and preferred in the context of the invention are of the disulfide type. Nevertheless, certain organosulfur species molecules participating in the capacity of the cathode and preferred in the context of the invention may also be of the trisulphide or polysulfide type.

An organosulfur species of polysulfide type participating in the capacity of the cathode may correspond to a compound according to formula II '.

in which :

 The groups R 1 and R 1 'are identical or different and represent a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain a or more heteroatoms;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO -, -COS-, -CSS-, -O-, -CONR ₅ -, hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C 12) alkenyl, - (C ₂ -C 12) alkynyl, -F , -CF ₃ , -NH ₂ , -NO ₂ , -SO ₂ H, -SH, -COOR 5, -COR 5, -SCOR 5, -CSSR 5 and -OR 5; with if L has a free connection then it allows to connect L to Ri 'or to L' and if L 'has a free connection then it makes it possible to connect L' to Ri or to L;

the group R ₅ represents a group selected from: a hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl; and

 n is an integer between 2 and 5, the terminals are included.

In particular, the groups R 1 and R 1 'may respectively represent the groups - R 2 -R 4 -R 3 - and -R 2 -R 4 -R 3' - in which:

- the groups R _2, R _3, R ₂ 'and R _3' are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C ₁ - Ci ₂₎ alkyl-, - (C ₂ -C ₂₎ alkényle-, - (C ₂ -C ₂₎ alkynyle-, -aryl-, -cycloalkyle-, substituted or unsubstituted;

the groups R ₄ and R ₄ 'are identical or different and represent a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- and -O-;

the group R ₅ represents a group selected from: a hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl.

Thus, preferably, the organosulfur species participating in the capacity of the cathode may correspond to the compounds of formula N'a:

where n is an integer from 2 to 5, the terminals are included. The organosulfur species participating in the capacity of the cathode may also correspond to a mixture of organosulfur species. In this case in the context of polysulfides, the organosulfur species may correspond to a mixture of compounds according to the formula N'a, said compounds being identical and having different values of n, in which n has an average value of between 2 and 5. .

Alternatively, the organosulfur species of the polysulfide type participating in the capacity of the cathode may correspond to a compound according to formula VI-1:

in which

 the groups F½ and R12 'are identical or different and represent a group

 compound of 1 to 20 carbons, branched or linear, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms; and

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO- , -COS-, -CSS-, -O-, -CONR ₅ -, hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C 12) alkenyl, - (C ₂ -C 12) alkynyl, -F, -CF _3, -NH _2, -NO2, -SO2H, -SH, -COOR 5, -COR 5, - COSR5, -CSSR5 and -OR5; if L has a free connection then it makes it possible to connect L to R ₁₂ 'or L' and if L 'has a free connection then it makes it possible to connect L' to R12 or to L; and

 the group R5 represents a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl.

In particular, the groups R12 and R12 'may respectively represent the groups - R2-R4-R3- and -R2 -R4 -R3- in which:

the groups R2, R3, R2 'and R3' are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C1-C12) alkyl-, - (C2-C12) alkenyl-, - (C2-C12) alkynyl-, -aryl-, -cycloalkyl-, substituted or unsubstituted; the groups R ₄ and FU 'are identical or different and represent a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, - CSS- and -O-; and

the group R ₅ represents a group selected from: a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl.

As will be presented in the examples, in this context, the organosulfur species participating in the capacity of the cathode may correspond to the following compounds:

Alternatively, the organosulfur species of the polysulfide type participating in the capacity of the cathode may correspond to a compound according to formula VI-2:

in which

the groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO -, -COS-, -CSS-, -O-, -CONR ₅ -, a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl, - (C ₂ -C ₁₂ ) alkynyl , -F, -CF _3, -NH _2, -N0 _2, -S0 ₂ H, -SH, -COOR _5, -COR _5, -

COSR5, -CSSR5 and -OR5; if L has a free connection then it allows to connect L to R ₁₂ 'or L' and if L 'has a free connection then it allows to connect L' to R ₁₂ or L;

the group R ₅ represents a group selected from: a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl; and the groups R13 and R13 'are identical or different and represent a group composed of 1 to 20 carbons, branched or linear, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or several heteroatoms.

In particular, the groups F 1 and R ₁₃ 'may respectively represent the groups -R 2 -R 4 -R 3 -and R ₂ ' -R ₄ '-R ₃ ' - in which:

the groups R ₂ , R ₃ , R ₂ 'and R ₃ ' are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C1-

C12) alkyl-, - (C2-C12) alkenyl-, - (C2-C12) alkynyl-, -aryl-, -cycloalkyl-, substituted or unsubstituted;

the groups R ₄ and R ₄ 'are identical or different and represent a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, - CSS- and -O-; and the group R5 represents a group selected from: a hydrogen, - (CrCi2) alkyl,

(C2-C12) alkenyl or - (C2-C12) alkynyl.

As will be presented in the examples, in this context, the organosulfur species participating in the capacity of the cathode may correspond to the following compounds:

In particular, the organosulfur species can comprise at least one thiol group, for example it comprises a thiol group or two thiol groups.

An organosulfur species of thiol type participating in the capacity of the cathode may correspond to a compound according to formula VII. in which :

 X is selected from hydrogen and the group M;

 M is selected from sodium, lithium, ammonium, sulfonium or quaternary phosphonium;

The group R 1 represents a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms; The L group represents a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- , -O-, - CONR ₅ -, a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl, - (C ₂ -C ₁₂ ) alkynyl, -F, -CF ₃ , - NH 2, -NO 2, -SO 2 H, -SH, -COOR 5, -COR 5, -COSR 5, -CSSR 5 and -OR 5; with if L has a free connection then it makes it possible to connect L to Ri; and

the group R ₅ represents a group selected from: a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl.

In particular, the group R 1 may represent the groups -R ₂ -R ₄ -R ₃ - in which:

- the groups R ₂ and R ₃ are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C ₁ - Ci ₂₎ alkyl-, - (C ₂ -C ₂ ) alkenyl-, - (C ₂ -C ₁₂ ) alkynyl-, -aryl-, -cycloalkyl-, substituted or unsubstituted;

the group R ₄ represents a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- and -O-;

the group R ₅ represents a group selected from: a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl or - (C ₂ -C ₁₂ ) alkynyl.

[00102] Preferably, X is a hydrogen.

The organosulfur species participating in the capacity of the cathode may then be a molecule selected from: methyl mercaptan, ethyl mercaptan, isopropyl mercaptan, tert-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, tertiononyl mercaptan, tertiododecyl mercaptan thioglycolic acid or 2-ethylhexyl thioglycolate (2-EHTG). In particular, the organosulfur species may comprise at least two thiol groups, for example the organosulfur species may comprise two thiol groups. As will be presented in the examples, in this context, the dithiol-type organosulfur species participating in the capacity of the cathode may be a linear molecule and may correspond to the following compounds:

[00106] The thiol-type organosulfur species participating in the capacity of the cathode may also be a molecule comprising one or more rings, cycloalkyl, aryl or heteroaryl, for example with the following compounds:

[00107] Advantageously, the organosulfur species participating in the capacity of the cathode may be selected from: 1,8-dimercapto-3,6-dioxaoctane (DMDO-compound VIIa), 2,5-dimercapto-1,3 , 4-thiadiazole (DMTD) or bis-DMTD.

In particular, a thiol-type organosulfur species participating in the capacity of the cathode may correspond to a compound according to formula VIII

In which :

 The groups RM, R15, Rie, R17, and Rie are identical or different and represent a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl, - (C2-

Ci ₂₎ alkynyl, -F, -CF _3, -NH _2, -N0 _2, -S0 ₂ H, -SH, -COOR 5, -COR _5, -COSR5, -CSSR ₅ and -OR 5; and

 the group R5 represents a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl.

[00109] The organosulfur species participating in the capacity of the cathode may be a cyclic molecule and may correspond to the following compounds: (Villa)

In particular, the organosulfur species can comprise at least one group of thioacid type.

[001 1 1] An organosulfur species of thioacid type participating in the capacity of the cathode may correspond to a compound according to formula IX.

in which :

 - G is an atom selected from: oxygen or sulfur;

 The group R19 represents a group composed of 1 to 19 carbons, branched or linear, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms;

The L group represents a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- , -O-, - CONR ₅ -, a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl, - (C ₂ -C ₁₂ ) alkynyl, -F, -CF ₃ , - NH2, -NO2, -SO2H, -SH, -COOR5, -COR5, -COSR5, -CSSR5 ot -OR5; with if L has a free connection then it makes it possible to connect L to R ₁₉ ;

- the group R ₅ represents a group selected from: hydrogen, - (Ci-Ci ₂₎ alkyl, - (C ₂ -C ₂₎ alkenyl or - (C ₂ -C ₂₎ alkynyl.

In particular, the group R19 may represent the groups -R2-R4-R3- in which: the groups R ₂ and R ₃ are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C1-C12) alkyl-, - (C2-C12) alkenyl- - (C2-C12) alkynyl-, -aryl-, -cycloalkyl-, substituted or unsubstituted;

the group R ₄ represents a group selected from: a single bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- and -O-; and

 the group R5 represents a group selected from: a hydrogen, - (CrCi2) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl.

[001 13] For example, the organosulfur species participating in the capacity of the cathode may be thioacetic acid.

As mentioned, the organosulfur species participating in the capacity of the cathode according to the invention may correspond to an oligomer or a polymer. The oligomer and the polymer may include disulfide, trisulphide, polysulfide functions as well as thiol or thiolate functions. Thus, it is possible to describe these compounds as polysulfides, poly (polysulfides), polythiols or polythiolates. In general, the organosulfur species may correspond to an oligomer or polymer with alkyl or aryl chain monomers, which may comprise heteroatoms, being linear, cyclic or three-dimensional (i.e., dendrimers).

In particular, the organosulfur species advantageously comprises a repetition of the unit according to formula I and may correspond to an oligomer or a polymer that can be formed from monomers according to formula I.

[001 16] Thus, the organosulfur species may for example correspond to a compound of formula X:

In which :

The groups R 1 and R 1 'are identical or different and represent a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example from alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms;

The groups L and L 'are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, - COO-, -CO- , -COS-, -CSS-, -O-, -CONR ₅ -, hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -C 12) alkenyl, - (C ₂ -C 12) alkynyl, -F, -CF ₃ , -NH ₂ , -NO ₂ , -SO ₂ H, -SH, -COOR 5, -COR 5, -SCOR 5, -CSSR 5 and -OR 5; if L has a free connection then it allows to connect L to RL or to L 'and if L' has a free connection then it makes it possible to connect L 'to Ri or to L; and

 the group R5 represents a group selected from: a hydrogen, - (CrCi2) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl; and

 n is an integer between 1 and 5, the terminals being included; and

 m is an integer between 2 and 1000, the terminals being included.

In particular, the groups R 1 and R 1 'can respectively represent -R 2 -R 4 -R 3 -and -R 2'-R ₄ ' -R ₃ '- in which:

 the groups R2, R3, R2 'and R3' are identical or different and represent a group selected from: a single bond, a double bond, a triple bond, - (C1-C12) alkyl-, - (C2-C12) alkenyl-, - (C2-C12) alkynyl-, -aryl-, -cycloalkyl-, substituted or unsubstituted;

the groups R ₄ and R ₄ 'are identical or different and represent a group selected from: a single bond, -NH R5-, -SO2-, -S-, -COO-, -CO-, -COS-, - CSS- and -O-; and

the group R5 represents a group selected from: a hydrogen, - (CrCi2) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl.

Alternatively, the organosulfur species may, for example, correspond to a compound of formula X ':

in which :

the groups R24 and R25 are identical or different and represent a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl, - (C2-C12) alkynyl, - F, -CF _3, -NH -N0 _{2I 2I} -SO2H, -SH, -COORs, -CORs, -COSRs, -CSSR5 and -OR _5; and the group R5 represents a group selected from: a hydrogen, - (Ci-C12) alkyl,

(C2-C12) alkenyl or - (C2-C12) alkynyl.

 n is an integer between 1 and 5, the terminals being included; and

 - m is an integer between 1 and 1000, the terminals being included.

For example, the organosulfur species participating in the capacity of the cathode may correspond to the following compound:

The organosulfur polymer species according to the invention can be formed from organosulfur species having two thiol functions. For example, the organosulfur polymer species participating in the capacity of the cathode may correspond to polymers formed for example at least in part by compounds according to formula VII in which L is a -SH function. The organosulfur species participating in the capacity of the cathode may correspond to a compound according to formula XI:

in which the group R 1 represents a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl or cycloalkyl type, arylalkyl or alkylaryl and may contain one or more heteroatoms; and m is an integer between 2 and 1000, the terminals being included.

The organosulfur species may for example correspond to the following compounds:

in which n is between 1 and 5, m is between 2 and 1000, the terminals being included.

in which m is between 2 and 1000

in which m is between 2 and 1000

In particular, the group R 1 may represent a substituted or unsubstituted aryl or heteroaryl group. More particularly, in the case where R 1 is a substituted aryl, the organosulfur species can correspond to a compound according to formula XII: in which :

The L group represents a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- , -O-, - CONR ₅ -, a hydrogen, - (C ₁ -C ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl, - (C ₂ -C ₁₂ ) alkynyl, -F, -CF ₃ , -

NH2, -NO2, -SO2H, -SH, -COOR5, -COR5, -COSR5, -CSSR5 ot -OR5; with if L has a free bond then it makes it possible to connect L to the terminal sulfur; and

R20 groups, R21, R22, and R23 are identical or different and represent a group selected from: hydrogen, - (Ci-Ci ₂₎ alkyl, - (C ₂ -C ₂₎ alkenyl, - (C ₂ -C ₂ ) alkynyl, -

F, -CF ₃ , -NH ₂ , -NO ₂ , -SO ₂ H, -SH, -COORs, -CORs, -COSRs, -CSSR ₅ and -OR ₅ ;

 the group R5 represents a group selected from: a hydrogen, - (C1-C12) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl; and

 m is an integer between 2 and 1000, the terminals being included.

The organosulfur species participating in the capacity of the cathode may then correspond to the following cyclic compounds:

the)

The organosulfur polymer species according to the invention may also correspond to an oligomer or a polymer formed from compounds according to formula I to form a molecule in which the L group is linked to the R1 group of another molecule, directly or via a substituent of the group R1.

In this context, the organosulfur polymer species according to the invention may correspond to the compounds according to formula XIII:

In which :

Wherein X is selected from sodium, lithium, ammonium, sulfonium, or The group R 1 represents a group composed of 1 to 20 carbons, branched or linear or cyclic, unsaturated or unsaturated, for example of the alkyl, aryl, heteroaryl, cycloalkyl, arylalkyl or alkylaryl type and which may contain one or more heteroatoms; The L group represents a group selected from: a single bond, a double bond, a triple bond, -NHR ₅ -, -SO ₂ -, -S-, -COO-, -CO-, -COS-, -CSS- , -O-, - CONR ₅ -, a hydrogen, - (CrCi ₂ ) alkyl, - (C ₂ -C ₁₂ ) alkenyl, - (C ₂ -C ₁₂ ) alkynyl, -F, -CF ₃ , -NH 2, -NO2, -SO2H, -SH, -COOR5, -COR5, -COSR5, -CSSR5 and -OR5; if L has a free connection then it allows to connect L to RL or to L 'and if L' has a free connection then it makes it possible to connect L 'to Ri or to L; and

 the group R5 represents a group selected from: a hydrogen, - (CrCi2) alkyl, - (C2-C12) alkenyl or - (C2-C12) alkynyl; and

 m is an integer between 2 and 1000, the terminals being included.

The organosulfur species participating in the capacity of the cathode may therefore correspond to the following linear compounds:

I l ia) in which m is an integer between 2 and 1000, the terminals being included or:

(XI Mb) In particular, the group R 1 may represent an aryl or heteroaryl group. In the case where R 1 is a substituted aryl or a substituted heteroaryl, the organosulfur species may correspond to the following compound:

(XI Ile) in which m is an integer between 2 and 1000, the terminals being included

The catholyte may contain a mixture of organosulfur species participating in the capacity of the cathode.

When the organosulfur species according to the invention have been represented are the thiol form, it should be understood that the invention also covers these organosulfur species in the form of thiolates. The counterion is then advantageously selected from: sodium, lithium, ammonium, sulfonium and quaternary phosphonium.

When the organosulfur species participating in the capacity of the cathode is a polymer then, it can also act as a polymeric binder.

Such an organosulfur species also acting as a polymeric binder may for example be selected from: the compound Xla, the compound Xlb, the compound Xlc, the copolymers of polyphenylene disulfide, and any other polymers containing the disulfide sequences -SS- or polysulfides -S _n - in the main polymer chain and -SH groups in the functionalities

In this context, a formulation of the organosulfur species can be in liquid form with very low viscosity at room temperature or can have a viscosity greater than 20,000 cPs forming a viscous gel or be in the solid state if the compound is mainly formed of polymer.

Alternatively, the organosulfur species participating in the capacity of the cathode may be associated with the separator. Additives to the catholite

The catholyte may further comprise sulfur in the elemental state. In this case, the sulfur in the elemental state is preferably in admixture with a thiolate compound.

In particular, the catholyte comprises sulfur in the elemental state in a molar ratio (sulfur in the elemental state) / (thiolate type compound) of between 1 and 10.

The concentration of sulfur in the elemental state in the catholyte may for example be greater than or equal to 0.05 mol / L, preferably greater than or equal to 0.1 mol / L, more preferably greater than or equal to at 0.2 mol / L. Sulfur in the elemental state is generally present at a concentration of less than 5 mol / L.

The thiolate concentration in turn is generally less than or equal to 0.5 mol / L. It may for example be greater than or equal to 0.05 mol / L, preferably greater than or equal to 0.1 mol / L, more preferably greater than or equal to 0.2 mol / L.

[00139] Different sources of native sulfur are commercially available. The particle size of the sulfur powder can vary widely. The sulfur can be used as it is, or the sulfur can be previously purified by different techniques such as refining, sublimation, or precipitation. The sulfur, or more generally the sulfurized material, can also be subjected to a preliminary grinding and / or sieving step in order to reduce the size of the particles and to tighten their distribution.

The catholyte makes it possible to transport the alkali metal ions from one electrode to the other. The catholyte may therefore be a liquid catholyte comprising one or more alkali metal salts, such as a lithium salt, dissolved in an organic solvent.

Thus, the catholyte further comprises one or more alkali metal salts, such as ATFSI, AFSI, ANO ₃ , ATDI, ACF ₃ SO ₃ , AFO ₃ , ABO ₂ , ACIO ₄ , APF ₆ , ACI0 ₄ , A2B12F12, ABC _4. 0 ₈ , ABF ₄ , AF, inorganic polysulfide salts A _Z S _X , or mixtures thereof,

with A selected from Li, Na, K, Rb or Cs

 x an integer greater than or equal to 2,

z an integer greater than or equal to 2. [00142] The catholyte may thus comprise a lithium selected preferably salt from: lithium fluorate (UFO3), lithium metaborate (UBO2), lithium perchlorate (UCIO4), lithium nitrate (UNO _3), lithium bis (oxalato ) borate (LiBOB or ίίB (q ₂ q ₄ ) ₂ ), lithium trifluoromethanesulfonate (LiTF), (Bis) trifluoromethanesulfonate lithium imide (LiTFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI) , bis (fluorosulfonyl) lithium imide (LiFSI), lithium hexafluorophosphate (LiPF _6), lithium perchlorate (UCIO _4), lithium trifluoromethylsulfonate (CF ₃ SO ₃ U), lithium trifluoroacetate (CF ₃ COOU) dodécafluorododécaborate of dilithium (U ₂ B ₁₂ F ₁₂ ), lithium bis (oxalate) borate (LiBCe) and lithium tetrafluoroborate (UBF ₄ ), the mineral polysulfides of Li, S _y Li, with y an integer greater than or equal to 2 , and their mixtures.

Even more preferably, the catholyte further comprises one or more lithium salts, such as LiTFSi, LiFSi, LiTDI, UNO3, UCF3SO3, the mineral polysulfides of Li, S _y Li, with y an integer greater than or equal to at 2, and mixtures thereof.

[00144] Even more preferably, the catholyte comprises LiTFSi or LiFSi.

The concentration of the alkali metal salt or salts in the catholyte is preferably between about 0.1 to 2 mol / L, preferably from about 0.2 to 1 mol / L, and more preferably from 0, 25 to about 0.75 mol / L.

The catholyte of the battery according to the invention is non-aqueous, that is to say that it does not include water or aqueous solvents. Thus, the catholyte according to the invention preferably comprises less than 50 ppm of water and more preferably less than 25 ppm of water.

The catholyte may for example comprise a polymeric binder, said polymeric binder not participating in the capacity of the cathode.

The polymeric binder may have a molar mass greater than 10,000 g. mol ^-1 , preferably greater than 50,000 g. mol ^-1 , and more preferably greater than 100,000 g. mol ^-1 . Depending on its molecular weight, the polymeric binder may be capable of forming a liquid, gelled or solid catholyte.

A solid catholyte is a solid electrolyte at room temperature, preferably comprising a mixture of polymers and lithium salts. This type of catholyte can be used without a separator because it offers a positive and negative physical separation of the electrodes. Nevertheless, the operation of the battery must be conducted at a temperature higher than the room temperature, to allow the molten state of the catholyte and the sufficient displacement of the lithium ions (T> 65 ° C for the POE).

 [00150] A gelled catholyte is a catholyte in which a polymer is mixed with a lithium salt, but also with a solvent or a mixture of organic solvents. The salt and the solvent (s) are trapped in the polymer, which is then said plasticized. The gelled catholyte can also act as a positive and negative electrode separator, and thus is not coupled to a conventional liquid electrolyte separator. On the other hand, the difference lies in the cycling temperature, since this type of electrolyte membrane operates at ambient temperature.

 The polymeric binders may for example be polyethers, polyesters or polyfluoroes. Preferably, the polymeric binder is selected from:

 homopolymers and copolymers of ethylene oxide (e.g. POE, POE copolymer), methylene oxide, propylene oxide, epichlorohydrin, allylglycidyl ether;

 halogenated polymers such as homopolymers and copolymers of vinyl chloride, vinylidene fluoride (PVdF), vinylidene chloride, ethylene tetrafluoride, or chlorotrifluoroethylene, copolymers of vinylidene fluoride and hexafluoropropylene (PVdF) -co-HFP);

 homopolymers and copolymers of (meth) acrylate such as poly (methylmethacrylate);

 - and their mixtures.

[00152] A catholyte in the gelled state at 25 ° C may comprise from 20 to 70% by weight of polymer binder, and preferably from 30 to 60% by weight of polymer binder, relative to the total mass of the gelled polymer electrolyte.

In the context of a solid catholyte, it may comprise an alloy based on lithium, germanium and / or silicon. Preferably, the catholyte comprises an alloy selected from: U2SP2S5, U2SP2S5-U-U2SP2S5 UBH4, and Li _{2 S-P2S5-GeS2,} or other formulations of the ceramic U2S-X-P2S5 family (with x sulfide, oxide, selenide or halide). Also, the ceramic electrolyte may be composed of heterogeneous metal sulfides, in the amorphous (vitreous) or crystalline state. The ceramic compounds based on metal oxide can also be used. More preferably, the ceramic solid electrolyte is selected from U2S-X-P2S5 type formulations (with x sulfide, oxide, selenide or halide). The catholyte may contain other additives whose components do not contribute to the capacity of the system. These additives are generally present in proportions of less than 20% by weight of the total mass of the catholyte, preferably less than 10%.

The catholyte may contain protective additives lithium interfaces or carbon-sulfur composite material. For example, the catholyte may comprise additives selected from:

nitrogen-containing additives such as lithium nitrate (UNO ₃ ) which is very effective in suppressing the shuttle mechanism due to the passivation of the lithium surface, or nitromethane (CH ₃ NO ₂ ), an FSI anion of LiFSI salt; can also participate in this passivation effect;

organic polysulfide compounds, of general formula P2S _X such as phosphorus pentasulfide (P ₂ S ₅ ), capable of limiting the irreversible deposition of Li ₂ S on the lithium metal electrode, with x an integer greater than or equal to 2 ;

 one or more electrical conductors, advantageously a carbon-based electrical conductor, such as carbon black, graphite or graphene, generally in proportions ranging from 1 to 10% by weight relative to the sulfur-containing material; . Preferably, the carbon black is used as the electrical conductor; and or

 - One or more electron donor elements to improve the electronic exchanges and regulate the length of the polysulfides during charging, which optimizes the charge / discharge cycles of the battery. As electron donor elements, it is advantageous to use an element, in the form of a powder or in the form of a salt, of columns IVa, Va and Via of the periodic table, preferably chosen from Se, Te, Ge, Sn, Sb, Bi. , Pb, Si or As.

These additives are generally present in proportions of between 0.5 and 5% by weight of the total mass of catholyte.

The catholyte described above may contain one or more organic solvents in variable proportions.

The organic solvent may for example be selected from: a monomer, an oligomer, a polymer and a mixture thereof. In particular, the organic solvent comprises at least one compound selected from: an amide, a carbonate ester, an ether, a sulfone, a ketone, a fluorinated compound, a sulfoxide-amide, toluene and a sulfoxide. The amide is preferably selected from N-methyl-2-pyrrolidone (NMP) or N, N-dimethylformamide (DMF). The sulfoxide is preferably dimethylsulfoxide. The dimethylsulfoxide may advantageously be used in combination with lactones (preferably gamma butyrolactone and valerolactone), pyrrolidones (eg NMP or 2-pyrrolidone), sulfonamides, or ketones (eg acetone, trimethylcyclohexanone, cyclohexanone).

 The organic solvent is preferably a solvent suitable for lithium-sulfur batteries. Thus, preferably, the organic solvent comprises at least one compound selected from: a carbonate ester, an ether, a sulfone, a fluorinated compound and toluene.

The ethers make it possible in particular to obtain good solubilization of lithium polysulfides and although having dielectric constants generally lower than the carbonates.

 Thus, preferably, the organic solvent is selected from an ether such as 1,3-dioxolane (DIOX) or 1,2-dimethoxyethane (DME) or a carbonate ester such as dimethyl carbonate ( DMC) or propylene carbonate (PC).

 The organic solvent may also comprise a combination of solvents. For example, it may include an ether and a carbonate ester. This can reduce the viscosity of a mixture having a high molecular weight carbonate ester.

 [00163] Preferably, the organic solvent is selected from: 1,3-dioxolane (DIOX), 1,2-dimethoxyethane (DME), ethylene carbonate (EC), diethyl carbonate (DEC) , propylene carbonate (PC), dimethyl carbonate (DMC), methyl ethyl carbonate (EMC), methylpropylcarbonate, tetrahydrofuran (THF), 2-methyltetrahydrofuran, methylpropylpropionate, ethylpropylpropionate, methyl acetate, diglyme (2-methoxyethyl ether), tetraglyme, diethylene glycol dimethyl ether (diglyme, DEGDME), polyethylene glycol dimethyl ether (PEGDME), tetraethylene glycol dimethyl ether (TEGDME), ethylene carbonate, propylene, butyrolactone, dioxolane, hexamethylphosphoamide, pyridine, dimethylsulfoxide, tributylphosphate, trimethylphosphate, N-tetraethylsulfamide, sulfone and mixtures thereof.

More preferably, the organic solvent is selected from: tetrahydrofuran, 2-methyltetrahydrofuran, dimethylcarbonate, diethylcarbonate, ethylmethylcarbonate, methylpropylcarbonate, methylpropylpropionate, ethylpropylpropionate, methylacetate, dimethoxyethane, 1,3-dioxolane, diglyme (2-methoxyethyl ether), tetraglyme, ethylene carbonate, propylene carbonate, butyrolactone, dioxolane, hexamethyl phosphoamide, pyridine, dimethylsulfoxide, phosphate tributyl, trimethyl phosphate, N-tetraethylsulfamide, sulfone and mixtures thereof. Other solvents may also be used such as, for example, sulfones, fluorinated compounds or toluene.

 Preferably, the organic solvent is a sulfone or a mixture of sulfones. Examples of sulfones are dimethylsulfone and sulfolane. The sulfolane may be used as a single solvent or in combination with, for example, other sulfones. In one embodiment, the electrolyte liquid solvent comprises lithium trifluoromethanesulfonate and sulfolane. Alternatively, the catholite may also be formulated without a solvent.

ELECTRODES

In the context of the present invention, the cathode 30 comprises sulfur capable of inserting / disinbing a salt such as sodium or lithium or forming an alloy therewith.

 During charging, the sodium or lithium ions are disintercalated by oxidation of the anode 10, pass through the separator 20 and migrate through the catholyte 40, ionic conductor, to the cathode 30, generally based on a carbon material, which is reduced with intercalation of these ions.

 Simultaneously, the electrons released at the anode 10 join the cathode 30 through the external circuit.

 During the first insertion into the material of the cathode or the first formation of the alloy with the material of the cathode, part of the salt (eg sodium or lithium initially contained in the anode is consumed in a controlled manner. irreversible.

 As will be presented in the examples, the inventors have developed a new battery having on the one hand a greatly increased capacity and, on the other hand, the advantage of not requiring a slow first training cycle that can lead to a loss of capacity.

[00172] The cathode

As has been mentioned, the battery according to the invention has a specific capacity greater than the specific capacity observed for this type of sulfur-based battery. A study of the literature shows in particular that the developed Li-S batteries has initial discharge capacities being all lower than 1670 mAh / g with the majority of initial discharge capacities of the order of 1000 mAh / g. Thus, current systems fail to utilize the full potential of sulfur and generally have non-optimal initial discharge capabilities. On the contrary, in the context of the present invention, the cathode advantageously has a specific capacity greater than 1300 mAh / g. To verify this characteristic, the specific capacitance of the cathode can be measured at a discharge rate of C / 10 and a temperature of 20 ° C. Classically, these values are a function of the sulfur mass present in the cathode.

Preferably, the cathode has a specific capacity greater than 1500 mAh / g, and more preferably above 2000 mAh / g.

In addition, to present such characteristics, the cathode also has a specific theoretical capacity greater than 1672 mAh / g. Thus, the present invention makes it possible to go beyond the true potential of the sulfur present in the cathode.

Such characteristics are possible in particular because of the presence in the catholyte of the organosulfur species participating in the capacity of the cathode.

The cathode according to the invention also has good coulombic efficiency. It is for example greater than or equal to 95%, and preferably greater than 98%.

As has been mentioned, the cathode comprises a composite material based on sulfur and carbonaceous material.

The composite material based on sulfur and carbonaceous material may further comprise other compounds such as additives detailed below.

The composite material based on sulfur and carbonaceous material (i.e. Sulfur-carbon composite material) has preferably been obtained by a melt process, for example in the context of a process including a compounding step. A process for preparing a sulfur-carbon composite that is particularly advantageous in the context of the invention is described in document WO2016 / 102865.

For optimum formation of the composite material, the carbonaceous material such as carbon nanotubes and / or carbon black, is mixed with sulfur in the molten state. For this, it is generally necessary to add an intense mechanical energy to achieve this mixture, which can be between 0.05 kWh / kg and 1 kWh / kg of active material, preferably between 0.2 and 0.5 kWh / kg of active ingredient. The carbonaceous material is thus dispersed homogeneously throughout the mass of the particles, and is not found only on the surface of the sulfur particles. Advantageously, the sulfur-carbon composite is obtained by a manufacturing process comprising a step of melting the sulfur and kneading the sulfur and the carbonaceous material. This melting and kneading step may advantageously be carried out by a compounding device. Thus, as shown in FIG. 2, the process according to the invention may comprise preliminary stages of formation of the Sulfur-Carbon composite, said stages of formation of the carbon Sulfur composite comprising:

 introduction into a device for compounding sulfur and carbon material,

 the implementation of a compounding step 130 so as to allow the fusion of the sulfur, and

 the kneading 140 of the molten sulfur and of the carbonaceous material.

To do this, a compounding device is preferably used, that is to say an apparatus conventionally used in the plastics industry for the melt blending of thermoplastic polymers and additives in order to to produce composites. The composite material based on sulfur and carbonaceous material according to the invention can thus be prepared according to a process comprising the following steps:

 (a) introduction 1 into a device for compounding sulfur and carbonaceous material,

 (b) melting 130 sulfur;

 (c) kneading 140 of the molten sulfur and the carbonaceous material;

 (d) recovering 150 the resulting mixture in agglomerated solid physical form; and

 (e) grinding in powder form.

In a compounding apparatus, the sulfur and the carbonaceous material are mixed using a high-shear device, for example a co-rotating twin-screw extruder or a co-kneader. The melt generally comes out of the apparatus in solid physical form agglomerated, for example in the form of granules, or in the form of rods which, after cooling, are cut into granules.

[00186] Examples of suitable co-mixers are the co-mixers ^® BUSS MDK 46 and those of the BUSS ^® MKS or MX, sold by Buss AG, which are made of a screw shaft provided with fins, disposed in a heating sleeve optionally consisting of several parts and whose inner wall is provided with kneading teeth adapted to cooperate with the fins to produce a shear of the kneaded material. The shaft is rotated and provided with oscillation movement in the axial direction by a motor. These co-kneaders may be equipped with a granule manufacturing system, adapted for example to their outlet orifice, which may consist of an extrusion screw or a pump.

 The co-kneaders that can be used preferably have an L / D screw ratio ranging from 7 to 22, for example from 10 to 20, while the co-rotating extruders advantageously have an L / D ratio ranging from 15 to 56. for example from 20 to 50.

To achieve optimum dispersion of the carbonaceous material in sulfur, it is preferable to apply a large mechanical energy, which is preferably greater than 0.05 kWh / kg of material.

 The compounding step is carried out at a temperature above the sulfur melting temperature. Thus, the compounding temperature can range from 120 ° C to 150 ° C.

 This process makes it possible to disperse efficiently and homogeneously a large amount of carbonaceous material in sulfur, despite the difference in density between the constituents of the composite material.

 The composite material according to the invention is advantageously in the form of a powder comprising particles having a mean size of less than 150 μm, preferably less than 100 μm, a median diameter d 50 of between 1 and 60 μm, preferably between 10 and 60 pm, more preferably between 20 and 50 pm, a median diameter d90 of less than 100 pm, preferably a diameter d100 of less than 50 pm, these characteristics being determined by laser diffraction. In order to obtain this powder morphology, a hammer mill, brush mill, ball mill, an air jet mill, or other methods of micronization of solid materials are generally used.

Sulfur used for the composite material

 According to a preferred embodiment of the invention, the sulfur used to form the composite material comprises at least sulfur in the elemental state and / or at least one sulfur-containing material.

 Thus, the composite material may comprise elemental sulfur alone, at least one other sulfur-containing material, or mixtures thereof.

[00194] Different sources of elemental sulfur are commercially available. The particle size of the sulfur powder can vary widely. The sulfur can be used as it is, or the sulfur can be previously purified by different techniques such as refining, sublimation, or precipitation. Sulfur, or more generally the sulfur material, can also be subjected to a preliminary step of grinding and / or sieving to reduce the size of the particles and tighten their distribution.

 The sulfurized material may be a sulfur-containing organic compound or polymer, or a sulfur-containing inorganic compound, or a mixture thereof in all proportions.

The sulfur-containing inorganic compounds that can be used as sulfur-containing materials are, for example, anionic polysulfides of alkali metal, preferably lithium polysulfides represented by the formula Li ₂ S _n (with n> 1).

The sulfur-containing organic compounds or polymers that can be used as sulfur-containing materials are, for example: polyDMDO, polysulfide-DMDO, polyphenylene disulfide copolymers, and any other polymer containing the disulifide -SS- or polisulfide -S _n - sequences without the polymer chain. main and -SH groups in the features.

The sulfur used to form the sulfur-carbon composite according to the invention may have different melting enthalpy values. This enthalpy of fusion (DH _fus ) may preferably be between 70 and 100 J. g ¹ . Indeed, the sulfurized material, for example in the elemental state or in the form of aromatic polysulfide, can be characterized by a melting enthalpy measured during a phase transition (fusion) by differential scanning calorimetry between 80 ° C. and 130 ° C (DSC - "Differential scanning calorimetry" in English terminology). Following the implementation of the process according to the invention, and in particular the incorporation of the carbon nanofillers in molten mode, there is a decrease in the enthalpy value (DH _fu ) of the composite with respect to the enthalpy value of the sulfur material of origin.

The composite material may comprise from 30 to 90% by weight of sulfur, preferably from 50 to 90% by weight of sulfur, and more preferably from 70 to 90% by weight of sulfur, relative to to the total mass of composite material.

The carbon material used for the composite material

According to the invention, the carbonaceous material may be selected from: carbon black, carbon nanotubes (CNTs), carbon nanofibers, graphene, acetylene black, graphite, carbon fibers and a mixture thereof in all proportions. Advantageously, the carbonaceous material is selected from carbon nanotubes (CNTs), carbon nanofibers, and graphene and a mixture thereof in all proportions.

Preferably, the carbonaceous material comprises at least carbon nanotubes or carbon nanofibers. That is, the carbonaceous material may correspond to carbon nanotubes and carbon nanofibers, alone or mixed with at least one other carbon nanocharge. In fact, unlike carbon black, the NTC type additives have the advantage of also conferring a beneficial adsorbent effect for the active ingredient by limiting its dissolution in the electrolyte and thus promoting better cyclability. The carbon nanocharge can here correspond to carbon black, graphene, acetylene black, graphite, carbon fibers and a mixture of these in all proportions.

The composite material may comprise from 10 to 70% by weight of carbonaceous material, preferably from 10 to 50% by weight of carbonaceous material, and more preferably from 10 to 30% by weight of carbonaceous material. , relative to the total mass of composite material.

The CNTs used in the composition of the composite material may be single-walled, double-walled or multi-walled, preferably multi-walled (MWNT) type.

The carbon nanotubes used according to the invention usually have a mean diameter ranging from 0.1 to 200 nm, preferably from 0.1 to 100 nm, more preferably from 0.4 to 50 nm, and better still , from 1 to 30 nm, indeed from 10 to 15 nm, and advantageously a length of more than 0.1 μm and advantageously from 0.1 to 20 μm, preferably from 0.1 to 10 μm, for example from approximately 6 pm. Their length / diameter ratio is advantageously greater than 10 and most often greater than 100. Their specific surface area is, for example, between 100 and 300 nf / g, advantageously between 200 and 300 nf / g, and their apparent density may notably be included. between 0.01 and 0.5 g / cm ³ and more preferably between 0.07 and 0.2 g / cm ³ . MWNT may for example comprise from 5 to 15 sheets and more preferably from 7 to 10 sheets.

 Carbon nanotubes are obtained in particular by chemical vapor deposition, for example according to the method described in WO06 / 082325. Preferably, they are obtained from renewable raw material, in particular of plant origin, as described in the patent application EP1980530.

 These nanotubes may or may not be treated.

An example of crude carbon nanotubes is in particular the trade name Graphistrength ^® C100 Arkema.

 These nanotubes can be purified and / or treated (for example oxidized) and / or milled and / or functionalized.

The grinding of the nanotubes may in particular be carried out cold or hot and be performed according to known techniques used in devices such as ball mills, hammers, grinders, knives, gas jet or any another grinding system capable of reducing the size of the entangled network of nanotubes. We prefer that this step grinding is practiced according to a gas jet grinding technique and in particular in an air jet mill.

 The purification of the crude or milled nanotubes can be carried out by washing with a sulfuric acid solution, so as to rid them of any residual mineral and metal impurities, such as for example iron from their process of preparation. The weight ratio of the nanotubes to the sulfuric acid may especially be between 1: 2 and 1: 3. The purification operation may also be carried out at a temperature ranging from 90 to 120 ° C, for example for a period of 5 to 10 hours. This operation may advantageously be followed by rinsing steps with water and drying the purified nanotubes. The nanotubes may alternatively be purified by high temperature heat treatment, typically greater than 1000 ° C.

 The oxidation of the nanotubes is advantageously carried out by putting them in contact with a solution of sodium hypochlorite containing from 0.5 to 15% by weight of NaOCI and preferably from 1 to 10% by weight of NaOCI, for example in a weight ratio of nanotubes to sodium hypochlorite ranging from 1: 0.1 to 1: 1. The oxidation is advantageously carried out at a temperature below 60 ° C. and preferably at room temperature, for a duration ranging from a few minutes to 24 hours. This oxidation operation may advantageously be followed by filtration and / or centrifugation, washing and drying steps of the oxidized nanotubes.

 The functionalization of the nanotubes can be carried out by grafting reactive units such as vinyl monomers on the surface of the nanotubes.

 In the present invention, it is preferable to use raw carbon nanotubes, which may be crushed, that is to say nanotubes which are neither oxidized nor purified nor functionalized and have undergone no other chemical and / or thermal treatment. .

The carbon nanofibers that can be used as carbonaceous material in the present invention are, like carbon nanotubes, nanofilaments produced by chemical vapor deposition (or CVD) from a carbon source which is decomposed on a catalyst comprising a transition metal (Fe, Ni, Co, Cu), in the presence of hydrogen, at temperatures of 500 to 1200 ° C. However, these two carbonaceous charges are differentiated by their structure, because carbon nanofibers consist of more or less organized graphitic zones (or turbostratic stacks) whose planes are inclined at variable angles with respect to the axis of the fiber. These stacks can take the form of platelets, fish bones or stacked cups to form structures generally ranging in diameter from 100 nm to 500 nm or more. Examples of usable carbon nanofibers have in particular a diameter of 100 to 200 nm, for example about 150 nm, and advantageously a length of 100 to 200 μm. It is possible to use, for example, VGCF ^® nanofibers from SHOWA DENKO.

 By graphene is meant a plane graphite sheet, isolated and individualized, but also, by extension, an assembly comprising between one and a few tens of sheets and having a flat structure or more or less wavy. This definition therefore includes FLG (Few Layer Graphene or Graphene NanoRibbons or Graphene NanoRibbons), NGP (Nanosized Graphene Plates), CNS (Carbon NanoSheets or nano-graphene sheets), and Graphene NanoRibbons. nano-ribbons of graphene). On the other hand, it excludes carbon nanotubes and nanofibers, which consist respectively of the winding of one or more sheets of graphene in a coaxial manner and of the turbostratic stacking of these sheets. It is furthermore preferred that the graphene used according to the invention is not subjected to an additional step of chemical oxidation or functionalization.

 The graphene used according to the invention is obtained by chemical vapor deposition or CVD, preferably in a process using a powdery catalyst based on a mixed oxide. It is typically in the form of particles having a thickness of less than 50 nm, preferably less than 15 nm, more preferably less than 5 nm and less than one micron side dimensions, preferably 10 nm at less than 1000 nm, more preferably 50 to 600 nm, or even 100 to 400 nm. Each of these particles generally contains from 1 to 50 sheets, preferably from 1 to 20 sheets and more preferably from 1 to 10 sheets, or even from 1 to 5 sheets which are capable of being disconnected from one another in the form of independent leaflets, for example during an ultrasound treatment.

Additives used for the composite material

According to one embodiment of the invention, the composite material further comprises at least one additive selected from a rheology modifier, a binder, an ionic conductor, a carbonaceous electrical conductor, an electron donor element or their association. These additives are advantageously introduced during a step 120, before or during the compounding step, so as to obtain a homogeneous composite material. Thus, preferably, a rheology modifier is added to the compounding device, preferably prior to performing the compounding step. In particular, it is possible to add, during mixing, during the compounding step, an additive modifying the rheology of the sulfur in the molten state, in order to reduce the self-heating of the mixture in the compounding device. Such additives having a fluidifying effect on liquid sulfur are described in application WO 2013/178930. Examples that may be mentioned include dimethyl sulphide, diethyl sulphide, dipropyl sulphide, dibutyl sulphide, dimethyl disulphide, diethyl disulphide, dipropyl disulphide, dibutyl disulphide, and the like. trisulfides, their tetrasulfide counterparts, their pentasulfide counterparts, their hexasulfide counterparts, alone or as mixtures of two or more of them in all proportions.

 The amount of rheology modifier additive is generally between 0.01% to 5% by weight, preferably from 0.1% to 3% by weight relative to the total weight of the carbon-sulfur composite.

 The composite material may comprise a binder, especially a polymeric binder. Thus, it is also possible to add during the formation of the composite material a polymeric binder as defined above.

 The composite material may comprise an electrical conductor and / or an electron donor element to improve the electronic exchanges and regulate the length of the polysulfides during charging, which optimizes the charge / discharge cycles of the battery.

These additive compounds can generally be added in proportions ranging from 1 to 10% by weight relative to the weight of sulfur-containing material.

[00224] Advantageously, the composite material based on sulfur and carbonaceous material may further comprise selenium. Selenium may be in the form of mineral or organic selenium (e.g. organoselenium compounds).

 The composite material may comprise from 0.1% to 10% by weight of selenium, preferably from 0.1 to 5% by weight of selenium, and more preferably from 0.1 to 2% by weight. in mass of Selenium, with respect to the total mass of composite material.

 The composite material may comprise from 1 to 50% by weight of ceramic type U2S-X-P2S5, preferably from 5 to 30% (with x sulfide, oxide, selenide or halide).

Constitution of the cathode

Thus, the cathode according to the invention comprises a composite material based on sulfur and carbonaceous material. Advantageously, the cathode may comprise from 30 to 95% by mass approximately of composite material.

In addition, the cathode according to the invention may in particular comprise one or more polymeric binder and one or more metal salt.

The polymeric binder

 The cathode may comprise a polymeric binder capable of improving the physicochemical and mechanical properties thereof.

The polymeric binder may be selected from homopolymers and copolymers of ethylene; homopolymers and copolymers of propylene; homopolymers and copolymers of ethylene oxide (eg POE, POE copolymer), methylene oxide, propylene oxide, epichlorohydrin, allylglycidyl ether, ter-octylphenyl ether ethylene of formula Ci4H ₂₂ 0 (C 2 H ₄ 0) n), the formulas of polyallylamines R (C 3 H ₅ NH ₂₎ n, the polyères of lactones, such as caprolactone P _(£ CL) _n, polymers of trimethylene carbonate P ( TMC) _n, or oligomer of caprolactone and trimethylene carbonate P (eCL _n -co-TMC _m) of the formula CH3 (C6Hio0 ₂₎ m (C 4 H ₆ 0 ₂₎ n CH 3, copolymers shaped type star [P (OE _n -co-OP _m ) acrylate] ₄ , where EO is ethylene oxide and EO is propylene oxide, the P [eCL _n -co- (AGE-g-MePEG7) _m ] where AGE is allylglycidylether and MePEG is methylpolyethyleneglycol (O-CH ₂ -CH ₂ ) 7-0-CH ₃ , P (SF 4 -g-MePEG 7) nb-PS _m where PS is a polystyrene group, SF ₄ is a group CH ₂ -CH ₂ -C ₆ F ₄ O-CH ₂ -CH ₂ . Finally, in general, any polymer obtained by polymerization of at least one cyclic monomer including in the ring chain a heteroatom selected from oxygen, nitrogen, phosphorus, silicon or sulfur atoms, which may be non-limiting type of lactone, carbonate, lactide, alkylene oxide and mixtures thereof; halogenated polymers such as homopolymers and copolymers of vinyl chloride, vinylidene fluoride (PVdF), vinylidene chloride, ethylene tetrafluoride, or chlorotrifluoroethylene, copolymers of vinylidene fluoride and hexafluoropropylene (PVdF). co-HFP) or mixtures thereof; polyacrylates such as polymethyl methacrylate; polyalcohols such as polyvinyl alcohol (PVA); electron-conducting polymers such as polyaniline, polypyrrole, polyfluorenes, polypyrenes, polyazulenes, polynaphthalenes, polyacetylenes, poly (p-phenylenevinylene), polycarbazoles, polyindoles, polyazepines, polythiophenes, p-phenylene polysulfide or mixtures thereof; cationic type polymers such as polyethyleneimine (PEI), polyaniline in the form of emeraldine salt (ES), poly (N-vinylimidazole quaternized), poly (acrylamide-co-diallyldimethyl ammonium chloride) (AMAC) or their mixtures; anionic polymers such as polystyrene sulfonate), gelatin or pectin; and one of their mixtures. According to a particular embodiment, the cathode comprises from 1 to 30% by weight of polymer binder, and preferably from 5 to 10% by weight of polymer binder, relative to the total mass of the cathode.

Metal salt

The cathode may further comprise at least one metal salt. Preferably the at least one metal salt is selected from lithium and sodium salts.

 More preferably, the cathode may further comprise at least one lithium salt.

 The lithium salt may be chosen from the salts already presented during the description of the catholyte.

Among the electrolyte salts, the salts are preferably chosen as LiTFSI, LiPF ₆ , LiFSI, LiTDI, LIBOB, LIDFOB, LiBF ₄ , UCIO4, LiAsFe, and mixtures thereof.

 [00237] LiTFSI or LiFSI are the preferred lithium salts.

The cathode may comprise from 1 to 25% by weight of metal salt, preferably from 1 to 15% by weight of metal salt, and more preferably from 1 to 10% by weight of metal salt, for example. relative to the total mass of the cathode.

The cathode according to the invention can be manufactured by any conventional method.

For example, the cathode may be prepared by mixing a composite material, based on sulfur and carbonaceous material, with at least one polymeric binder, optionally at least one metal salt, and optionally at least one solvent of said polymeric binder. , to obtain an electrode ink. The electrode ink can then be applied to at least one support.

The solvent of the polymeric binder may be selected from water, N-methylpyrrolidone, carbonate type solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate or the like. methyl and ethyl carbonate, acetone, alcohols such as methanol, ethanol or propanol, and mixtures thereof. The application of the electrode paste may be carried out by rolling or by coating. The application can be carried out on a current collector and / or a support film. The current collector may for example comprise an aluminum foil. The support film may for example be a plastic film of polyethylene terephthalate (PET) silicone type.

The manufacturing method of the cathode according to the invention may comprise a step of drying the electrode paste to obtain a positive electrode in the form of a supported film.

In addition, the cathode manufacturing method may comprise a calendering or extrusion step.

The cathode according to the invention may have a thickness ranging from 2 to 100 mm, and preferably from 10 to 60 mm.

The separator

Conventionally, the separator 20 is placed between the anode 10 and the cathode 30 and more particularly between the catholyte 40 and the anode 10.

The separator generally ensures perfect insulation between the two electrodes to avoid any risk of short circuit. Advantageously, it has sufficient mechanical strength to withstand the stresses due to variations in the volume of the active substances during the charging and discharging cycles, a chemical resistance sufficient to ensure its resistance over time since it is immersed in the electrolyte, and a suitable porous structure, to allow the diffusion of the anions and cations of the electrolyte, and to avoid any transport of active material from one electrode to the other.

The separator corresponds for example to an intermediate separating element placed between the anode and the cathode acting to separate the liquid electrolyte or gel solutions in contact with the anode and the cathode, through which the metal ions and their counterions move between the anode and the cathode.

The separator may take the form of a solid electrolyte or a separator 20 impregnated with a liquid catholyte.

The separator used in the organic lithium battery of the invention also makes it possible to ensure the electrical separation of the electrodes, while avoiding or limiting the diffusion of the organic redox structure of the positive electrode into the battery. In addition, the separator is stable vis-à-vis the electrolyte of the battery, that said electrolyte is in liquid or solid form (eg gelled polymer electrolyte). Preferably, a part of its structure is unreactive with respect to the organic or inorganic sulfur species.

The separator is generally made of an electronically non-conductive porous material, for example a polymer material based on polyolefins (e.g. polyethylene) or fibers (e.g. glass fibers or wood fibers).

In a particular embodiment, the porous separator has pores of average size ranging from about 50 nm to about 3 μm, preferably from about 50 nm to about 1 μm, and more preferably from about 100 nm to about 500 nm. Thanks to this porosity, said separator can be easily impregnated by the electrolyte while ensuring sufficient mechanical strength.

The polypropylene of the porous separator may be a homopolymer of polypropylene (PP) or a copolymer of polypropylene.

The porous separator may be impregnated with the polymers or copolymers of DMDO, Ph-S-S-R or other functionalities mentioned in the "cathode" part.

The separator may comprise an organofluorinated species such as polyvinylidene fluoride (PVDF) and copolymers or terpolymers, the typical representatives of which are the PVDF-TrFE (trifluoroethylene) copolymers or the PVDF-TrFE-CTFE (chlorotrifluoroethylene) terpolymers.

The separator advantageously comprises one or more ceramic alloys. The ceramic may be associated with the separator via a deposit for example via laser deposition (pulsed laser deposition).

Anode

The battery according to the invention also comprises an anode. In particular, the anode may comprise an anode active material comprising sodium or lithium. The anode active material is preferably a sodium or lithium-based composite material or a sodium or lithium-based alloy.

The anode active material may, for example, correspond to a lithium metal material or to a lithiated silicon (eg silicon coated with lithium, for example via electrolysis). The process of preparing the battery

The invention also relates to a method of manufacturing a sulfur-based battery as defined in the first subject of the invention, characterized in that it comprises a step of preparing a catholyte such as defined in the present invention comprising in particular at least one organosulfur species participating in the capacity of the cathode and a step of assembling an anode, a cathode and a porous separator as defined in the present invention.

When the organosulfur species has a thiol function, the preparation of the catholyte may comprise a prior step of reducing the organosulfur species by contacting with mineral lithium.

Preferably, the preparation of the catholyte further comprises the dissolution with stirring at least one lithium salt in an organic solvent, optionally at a temperature ranging from 20 to 120 ° C.

The method may comprise a step of impregnating the separator prior to the assembly step. The impregnation of the separator with the catholyte can be carried out by coiling the separator and a gelled catholyte film.

The method may also include a step of mounting the anode with the positive cathode, the separator and the catholyte to form an electrochemical cell.

The battery can then be charged and different cycles are carried out.

After assembly, the sulfur-based batteries generally require a preliminary formation step. During this training step, the batteries follow long charging and discharging cycles to create the interfaces necessary for their subsequent operation. However, advantageously, this is not the case for the battery according to the invention.

Thus, preferably, in the context of the invention, the method of manufacturing the battery according to the invention does not require a training step.

As illustrated by the examples below, the present invention provides a solution based on the reactivity of the organosulfur-containing catholyte to improve the capacity of Li-S batteries while maintaining system stability. rExemplesl

 Example 1 Preparation of a Sulfur / NTC Composite Material

The composite material (or "compound") sulfur / CNT is produced according to the method described in the patent application WO2016 / 102865.

Nanotubes (ARKEMA Graphistrength C100) and solid sulfur (50-800 microns) were introduced into the first feed hopper of a co-kneader BUSS MDK 30 (L / D = 15), equipped with a recovery extrusion screw and a granulation device.

The temperature setpoints within the co-kneader were as follows: Zone 1: 140 ° C .; Zone 2: 130 ° C.

At the outlet of the die, the mixture, consisting of 87% by weight of sulfur and 13% by weight of nanotubes, is in the form of granules obtained by the overhead cut cooled by air. The composite material is characterized by a density of 1.55 g / cm ³ and a bulk density of 1.05 g / cm ³ . Another specific feature of the composite material is the sulfur melting enthalpy measured by DSC (the value of D Hfus was measured between 90 and 130 ° C). For the starting sulfur D Hfus = 72 J g ^-1 . The granules of composite material after compounding demonstrate a value of 54 J g ^-1 .

The grinding of the granules was carried out in a hammer mill under nitrogen. The resulting composite material powder is characterized by a D 50 <50 μm and a bulk density of 0.90 g / cm ³ . This Sulfur / NTC composite material powder is then used as a cathode active material in the Li / S battery.

Example 2 - Reference cathode preparation 1 based on Sulfur

[00273] The mixture of (S / NTC): carbon black: PVDF = 60:30:10 is mixed in N-methyl-2-pyrrolidone to form an ink. The ink of semi-fluid consistency is deposited in a thin layer directly on carbon paper and dried for 3 hours at 60 ° C. The mass of sulfur active material is subsequently calculated by evaluating the amount deposited according to the percentage reported above. Sulfur active mass values are generally between 0.8 mg and 2 mg per 1 cm ² .

The elements of the battery: separator, cathode are dried at 80 ° C under vacuum for 24 hours and then assembled in glove boxes Example 3 Preparation of the Reference Electrode 2 Based on the Active Ingredient of Example 1 on Aluminum Foil

An ink formed according to Example 2 and then deposited on an aluminum sheet via a doctor blade technology (e.g. doctor blade). The film thus obtained was dried at 120 ° C for 20 minutes in an oven to obtain a cathode.

Example 4 Preparation of the reference electrode 3 based on the active ingredient of Example 1 self-supported and deposited on an aluminum grid.

The mixture of (S / NTC): carbon black: PTFE = 45:45:10 is mixed in N-methyl-2-pyrrolidone / ethanol to form a paste. The mixture of semi-solid consistency (paste) is shaped by simple pressing, between aluminum grid 3 tons for optimal adhesion.

Example 5 Preparation of a liquid catholyte

Two lithium salts UNO ₃ and LiTFSI (0.25 M / 0.75 M) were mixed with a solvent base consisting of a binary mixture DOL: DME. A liquid electrolyte with 1M lithium salt in DOL: DME was thus obtained. The water content is controlled and must not exceed 20ppm.

The electrolyte is or is not added to an organosulfur species (e.g. 0.2 M). Depending on the nature of the organosulfur species it is important to convert its concentration to thiolate function concentration (e.g., 0.4 M RS-).

In the case where the organosulfur species is a thiol (ie R-SH) or polythiol, it is preferable to carry out a prior ex-situ reduction 24 hours before assembly, under an inert atmosphere with lithium metal by adding an excess of lithium metal in the mixture of solvents / salts + R-SH previously prepared. The reaction is complete and leads to the formation of the corresponding lithium thiolate.

For example, for 1, 3 mg of sulfur in the cathode and 100 microlitre of DMDO-based electrolyte is 0.2 mol / L, there is then 0.02 millimoles of dithioles or 0.04 millimole RS-functions for 1, 3 mg of sulfur. The ratio S / RS- can then be 1.

The amount of active material in the electrode is 1.75 mg of S is 0.05 millimole. The proportion of inorganic sulfur / organic sulfur (sulfur from the organosulfur species participating in the capacity of the cathode) is equal to or substantially equal to 1.25.

Example 6 Preparation of a solid catholyte

The solid catholyte is prepared from the constituents shown in Example 5 except for the presence in the PVDF-co-HFP copolymer solution.

In addition, the catholyte is prepared by extrusion of the mixture and then by rolling the ink obtained at 125 ° C between two plastic films.

Example 7. Preparation and Testing of Li / S Batteries

The assembly is carried out by superposition of the lithium anode, the separator impregnated with the catholyte according to Example 5 and the sulfur-carbon cathode in a glove box.

The batteries Ref1, Ref2 and Ref3 are not in accordance with the invention since there is no organosulfur species participating in the capacity of the cathode in the catholyte.

The batteries 11 to I5 are in accordance with the invention and have different compounds and different concentrations. They are based on the electrodes formed according to Example 2.

The discharge curves are measured at ambient temperature, the current imposed at the first discharge (extraction of sulfur) is equivalent to a C / 10 regime (10 h of discharge.) The cycling of the batteries thus produced can also be done at higher temperature (45 to 50 ° C).

Example 8 Properties of the studied batteries

An example of a galvanostatic charge / discharge curve representing the initial discharge capacitance obtained for a reference battery and a battery according to the invention, comprising 0.4 M DMDO as an organosulfur species is presented in FIG. 3 and a summary results obtained is presented in the table below:

 Thus, the presence of at least one organosulfur species in the catholyte makes it possible to increase the initial discharge capacity of the battery significantly. Indeed, all the examples according to the invention have values of initial discharge capacities at a C / 10 regime much higher than the values of initial discharge capacities at a C / 10 regime of the comparative examples (Ref1, Ref2, Ref3). The increase compared to Ref1 based on the same electrode can reach more than 280% (see Ref1 vs 11). In addition, the discharge capacity at a C regime is also improved with an increase of up to more than 500% (see Ref1 vs 11).

[00291] Figure 4 shows further that the capacity of the battery increases over cycles performed in the presence of DMDO 0.2M. While FIG. 5 shows for 400 cycles, for a battery according to the invention comprising Diphenyldisulfide, an excellent efficiency of this battery as well as levels of discharge capacity well above the conventional level.

Finally, the addition of sulfur in the mineral state in the catholyte makes it possible to further increase the capacity of the battery according to the invention (result not shown).

Example 8 - Preparation of a solid catholyte where the organosulfur species is also a polymeric binder

The solid catholyte is prepared from the constituents shown in Example 5 where the organosulfur species is a polyDMDO. The catholyte is prepared by extruding the mixture and then rolling the ink obtained at 125 ° C between two plastic films.

Claims

claims 1. Battery comprising an anode, a separator, a cathode comprising a composite material based on sulfur and carbon material, and a catholyte, characterized in that the catholyte comprises at least one organosulfur species participating in the capacity of the cathode. 2. Battery according to claim 1 characterized in that the anode comprises an anode active material comprising sodium or lithium. 3. Battery according to one of claims 1 or 2, characterized in that the composite material was formed melt through a step of melting sulfur and kneading sulfur and carbon material. 4. Battery according to any one of claims 1 to 3, characterized in that the carbon material is selected from: carbon black, carbon nanotubes, carbon fibers, graphene, acetylene black, graphite, carbon nanofibers and a mixture of these in all proportions. 5. Battery according to any one of claims 1 to 4, characterized in that the composite material comprises sulfur in the elemental state. 6. Battery according to any one of claims 1 to 5, characterized in that the composite material further comprises selenium. 7. Battery according to any one of claims 1 to 6, characterized in that the at least one organosulfur species is selected from: an organic disulfide, an organic polysulfide, a thiol, a polythiol, a thiolate or a polythiolate. 8. Battery according to any one of claims 1 to 7, characterized in that the at least one organosulfur species is selected from compounds of the following formulas: RS _X R, R (SH) _n , R (SM) _X , R (COSH) _n , R (COSM) _n , RCOS _x R and a polymer having one or more functions -S _x -, -COS _x -, -SH, -SM, -COSH, -COSM,  With:  M selected from Li and Na; R selected from substituted or unsubstituted alkyl or aryl groups, x an integer greater than or equal to 2,  n an integer greater than or equal to 1. 9. Battery according to any one of claims 1 to 8, characterized in that the catholyte further comprises: one or more alkali metal salts, such as ATFSi, AFSi, ANO ₃ , ATDI, ACF ₃ SO ₃ , - inorganic and organic polysulfides salts A _{Z X} S and RS _X A, or - their mixtures,  with R selected from substituted or unsubstituted alkyl or aryl groups,  Selected from Li, Na, K, Rb or Cs,  x an integer greater than or equal to 2, and  z an integer greater than or equal to 2. 10. Battery according to any one of claims 1 to 9, characterized in that the catholyte further comprises one or more lithium salts, such as LiTFSi, LiFSi, LiTDI, UNO3, UCF3SO3, and mixtures thereof and Li polysulfides. RS _y Li with y an integer greater than or equal to 2 and R selected from alkyl or aryl groups, substituted or unsubstituted. 1 1. Battery according to any one of claims 1 to 10, characterized in that the catholyte may also comprise a polymeric binder. 12. Battery according to any one of claims 1 to 1 1, characterized in that the at least one organosulfur species is a polymer and is capable of behaving as a polymeric binder. 13. Battery according to claim 12, characterized in that the at least one organosulfur species acting as a polymeric binder is selected from a polymer containing the following functions: disulfide -SS-, polysulfides - S _n - with n a higher integer or equal to 2, and / or -SH. 14. Battery according to any one of claims 1 to 13, characterized in that the organosulfur species or species participating in the capacity of the cathode are present in the catholyte at a concentration greater than or equal to 0.05 mol / L. 15. Battery according to any one of claims 1 to 14, characterized in that it comprises mineral sulfur and organic sulfur and in that the molar ratio between the mineral sulfur and the organic sulfur is between 0.05 and And preferably between 0.1 and 7. 16. Battery according to any one of claims 1 to 15, characterized in that the cathode has a specific theoretical capacity greater than 1700 mAh / g. 17. Battery according to any one of claims 1 to 16, characterized in that the cathode has a specific capacity greater than 1300 mAh / g measured at a discharge rate equal to C / 10. 18. Battery according to any one of claims 1 to 17, characterized in that the cathode has a specific capacity greater than 500 mAh / g measured at a discharge regime equal to C / 1. 19. Battery according to any one of claims 1 to 18, characterized in that the cathode is capable of having a specific capacity greater than 1000 mAh / g measured at a discharge rate equal to C / 1 after 400 cycles. 20. Battery according to any one of claims 1 to 19, characterized in that it does not require a formation step. 21. A method of manufacturing a battery according to one of claims 1 to 19 characterized in that it comprises:  a step of preparing a catholyte comprising at least one organosulfur species participating in the capacity of the cathode, and  a step of assembling an anode, a cathode, a separator and the catholyte. 22. The manufacturing method according to claim 21, characterized in that it does not include a step of forming the battery after the assembly step.