WO2013045561A1

WO2013045561A1 - Electrochemical cell

Info

Publication number: WO2013045561A1
Application number: PCT/EP2012/069103
Authority: WO
Inventors: Martin Winter; Stefano Passerini; Simon LUX; Peter Bieker; Tobias PLACKE; Hinrich-Wilhelm MEYER
Original assignee: Westfälische Wilhelms-Universität Münster
Priority date: 2011-09-30
Filing date: 2012-09-27
Publication date: 2013-04-04
Also published as: DE102011054119A1

Abstract

The invention relates to an electrochemical cell comprising an electrode which reversibly absorbs and emits cations, an electrode which reversibly absorbs and emits anions, and an electrolyte comprising a conductive salt and a solvent, wherein the solvent comprises an ionic liquid or a mixture of an ionic liquid and an organic solvent.

Description

Electrochemical cell

The invention relates to an electrochemical cell, in particular a secondary

electrochemical cell based on the dual-ion insertion principle.

Secondary electrochemical cells are commonly referred to as rechargeable batteries and are distinguished from primary electrochemical cells by their rechargeability. Lithium-ion technology is currently the leading technology in the field of rechargeable battery storage systems, especially for applications in portable electronics. Lithium-ion batteries include two electrodes separated by a separator. The charge transport is via an electrolyte containing a lithium salt dissolved in a nonaqueous organic solvent. The electrolyte ensures ion transport between the two electrodes and

completes the electrical circuit. In lithium-ion batteries, lithium ions are reversibly stored or removed from the electrode active materials. When charging a lithium-ion battery Li ⁺ ions are transported from the cathode to the anode and during the discharge process change the Li ⁺ ions back from the anode to the cathode.

However, common lithium-ion batteries have various disadvantages. Thus, the cathodes can release oxygen, which in combination with the flammability of organic electrolytes safety concerns exist. Furthermore, in lithium-ion batteries as electrode material often metal oxides from mixtures of nickel and cobalt UD 40419 / SAM: AL used by the use of nickel and especially by cobalt the

Production costs are greatly increased. In addition, the heavy metals nickel and cobalt have a high toxicity. An alternative to conventional lithium-ion batteries form the so-called dual graphite systems, which are based on a storage of lithium in a graphite anode and an incorporation of anions in a graphite cathode. The graphite electrodes are also separated in dual graphite systems by a separator and the charge transport via an organic electrolyte containing a lithium salt. When charging a dual graphite system, however, the lithium ion from the electrolyte into the anode and parallel an anion, usually the counterion of the lithium salt, stored in the cathode. Therefore, this process is also referred to as dual insertion or dual-ion insertion principle. In the charged state, the electrolyte of the dual graphite system is thus depleted of Li ⁺ and anion, since these are as charge carriers in the two electrodes. During discharge, the ions are simultaneously released back to the electrolyte and thus the ion concentration is increased again.

A disadvantage of dual graphite systems, however, is that they use very high lithium salt concentrations. These high concentrations decrease at low levels

Temperatures the conductivity and thus the capacity of the cells. Because of the dual

Storage of Li ⁺ and anion, the function of a dual graphite cell is particularly dependent on the interaction of the individual components. Another disadvantage is that even with these systems, especially at higher temperatures due to a possible exothermic decomposition of the cell safety concerns. Another disadvantage of dual graphite systems is that they have a high capacity loss in the first cycle. Another disadvantage is that dual graphite systems throughout the

Life only low charging and discharging efficiencies reach. The present invention was therefore based on the object to provide an electrochemical cell which overcomes at least one of the aforementioned disadvantages of the prior art. In particular, the present invention was based on the object to provide an electrochemical cell which improved

Temperature resistance has.

This object is achieved by an electrochemical cell, in particular a secondary electrochemical cell, comprising a cation reversibly receiving and donating electrode, an anion reversible receiving and donating electrode and an electrolyte comprising a conducting salt and a solvent, wherein the solvent is an ionic liquid or a mixture an ionic liquid and an organic solvent.

Another object of the invention relates to the use of an ionic liquid as a solvent in an electrochemical cell, in particular a secondary electrochemical cell comprising a cation reversibly receiving and donating electrodes, anions reversibly receiving and donating an electrode and an electrolyte comprising a conducting salt and a solvent. Further advantageous embodiments of the invention will become apparent from the dependent claims.

Surprisingly, it has been found that an electrochemical cell based on the dual-ion insertion principle comprising as solvent an ionic liquid can have a very high capacity. Furthermore, it was found that when using an ionic liquid in a dual-ion insertion cell significantly higher charging and

Discharge currents could be realized when using organic electrolytes. A further advantage is that the inventive particular secondary electrochemical cell can provide a high cycle stability and high efficiency. In particular, it is further advantageous that the use of ionic liquids increases the safety of the electrochemical cell, in particular with regard to the flammability of the cell and the decomposition of the electrolyte at high temperatures

Temperatures can provide. Thus, the inventive

electrochemical cell to a higher reliability. Of particular advantage is that the electrochemical cell in the low temperature range, but especially in the

High temperature range can be operated. Furthermore, the electrochemical cell is less toxic than nickel and cobalt-containing lithium ion systems and therefore

more environmentally friendly.

The electrodes of the particular secondary electrochemical cell can absorb and release cations or anions reversibly. For the purposes of the present invention, the term "reversibly take up and release" is understood to mean that the active materials of the electrodes can reversibly store and disperse cations or anions, intercalate and deintercalate, or take up and release by compound formation or alloy formation. For the purposes of the present invention, the term reversibly intercalate and deintercalate means that a graphite or a carbon-based electrode can absorb and release cations or anions.

The cations and anions are provided from the electrolyte comprising a conducting salt. As the conductive salt, the salt of the electrolyte, which provides the charge transport, called. The conducting salt has a cation, preferably lithium and sodium, in particular lithium, and a counter anion. Suitable anions are, for example, complex halides of boron or phosphorus, for example tetrafluoroborate or

Hexafluorophosphate, and especially organic anions. For the purposes of this invention, the term "ionic liquid" is to be understood as meaning salts which form a class of liquids which exclusively contain ions and in which

Temperatures below 180 ° C are liquid. A useful ionic liquid may have only one anion and one cation, or have several different anions and / or cations, and / or be a mixture of ionic liquids.

An advantage of ionic liquids is that they are compared with organic ones

Solvents have a lower toxicity and hazard potential. Furthermore, ionic liquids often have only a small or hardly measurable vapor pressure. In addition, most ionic liquids are non-flammable. This is particularly advantageous for high operating temperature applications. Ionic liquids comprise at least one cation and at least one anion. Preferred are ionic liquids comprising an organic and / or inorganic anion and an organic and / or inorganic cation. In preferred embodiments of the present invention, the anion is an organic anion. Suitable counterions are organic and / or inorganic cations.

Suitable ionic compounds are, for example, those with a low melting point, preferably below ambient temperature, whose cation is of the onium type and has at least one heteroatom such as N, O, S or P, which carries the positive charge, and whose anion is wholly or partially at least one imide ion of the type (FX ¹ 0) N ^"(OX ² F), in which X ¹ and X ² are identical or different and comprise SO or PF.

In particular, the onium-type cation may comprise a compound of the following formula:

a compound of the following formula

a compound of the following formula

or a compound of the following formulas

7

: PR _H

ro

in which:

WO, S or N, and wherein N is optionally substituted by R ¹ , if the valency permits; R ¹ , R ³ , R ⁴ are the same or different and are H; - alkyl, alkenyl, oxaalkyl, oxaalkenyl, azaalkenyl, thioalkyl, thioalkenyl, dialkylazoradicals, wherein the radicals may be linear, branched or cyclic and comprise 1 to 18 carbon atoms; cyclic or heterocyclic aliphatic radicals of 4 to 26

Carbon atoms optionally comprising at least one side chain comprising one or more heteroatoms; - groups comprising a plurality of aromatic or heterocyclic nuclei which are condensed or uncondensed and which optionally contain one or more nitrogen, oxygen, sulfur or phosphorus atoms, two of which

Groups R ¹ , R ³ or R ^{4 may form} a ring or a heterocycle of 4 to 9 atoms and one or more groups R ¹ , R ³ or R ⁴ on the same cation may be part of a polymer chain; - R ² and R ⁵ to R ⁹ are the same or different and represent R ¹ , R ¹ 0- (R ¹ ) ₂ N-, R ^! S-, wherein R ^{1 is} as defined above.

Preferred cations include compounds of the formula:

the imidazolium, triazolium, thiazolium and oxazolium derivatives include; Bindings of the formula

the triazolium, oxadiazolium and thiadiazolium derivatives include;

Connecting the formula

preferably pyridinium derivatives

in which:

WO, S or N, and wherein N is optionally substituted by R ¹ , if the valency permits; R ¹ , R ³ , R ^{4 are the} same or different from each other and - H; - alkyl, alkenyl, oxaalkyl, oxaalkenyl, azaalkyl, azaalkenyl, thioalkyl, thioalkenyl, dialkylazoradicals, where the radicals may be linear, branched or cyclic and 1 to 18

Carbon atoms; cyclic or heterocyclic aliphatic radicals having from 4 to 26 carbon atoms which optionally comprise at least one side chain comprising one or more heteroatoms, such as nitrogen, oxygen or sulfur; Aryls, arylalkyls, alkylaryls and alkenylaryls having from 5 to 26 carbon atoms optionally comprising one or more heteroatoms in the aromatic nucleus; - Groups comprising a plurality of aromatic or heterocyclic nuclei which are condensed or uncondensed and the optionally contain one or more nitrogen, oxygen, sulfur or phosphorus atoms, wherein two groups R ¹ , R ³ or R ^{4 can form} a ring or a heterocycle having 4 to 9 atoms, and one or more groups R ¹ , R ³ or R ⁴ on the same cation may be part of a polymer chain; and R ² and R ⁵ to R ^{9 are the} same or different and R ¹ , R ^{1 is} O- (R ¹ ) ₂ N-, R'S-, wherein R ^{1 is} as defined above.

The groups R ^1, R ³ and R ⁴ may bear groups which are active in the polymerization, such as double bonds or epoxides, or reactive functional groups which are reactive in polycondensations, such as OH, NH ₂ and COOH. In the case where the cations carry double bonds, they may be homopolymerized or copolymerized with, for example, vinylidene fluoride, an acrylate, a maleimide, acrylonitrile, a vinyl ether, a styrene, etc. The epoxide groups can be polycondensed or with other epoxides

be copolymerized. The ammonium, phosphonium and sulfonium cations may have optical isomerism and the molten salts containing them are chiral solvents capable of promoting the formation of an enantiomeric excess in the reactions carried out in these environments. The ionic liquid may comprise, in addition to the aforementioned imide anion, at least one other anion selected from Cl ^- ; Br ^~ ; Γ; N0 ₃ ^" ; (MR ¹⁰ ) ₄ ^~ A (R ¹⁰ ) ₆ ^~ ; R ⁿ 0 ₂ ^" ; [R 1 NZ ¹ ] ^" ; [R ⁿ YOCZ ² Z ³ ] ^~ ; 4,5-dicyano-l, 2,3-triazole, 3,5-bis (R _F ) -l, 2,4-triazole,

Tricyanomethane, pentacyanocyclopentadiene, pentakis (trifluoromethyl) cyclopentadiene, derivatives of barbituric acid and meldrumic acid and their substitution products; where - M is B, Al, Ga or Bi; - A is P, As and Sb; R ¹⁰ is a halogen; R ¹¹ is H, F is an alkyl, alkenyl, aryl, arylalkyl, alkylaryl, arylalkenyl, alkenylaryl, dialkylamino, alkoxy or thioalkoxy group, each having 1 to 18 carbon atoms and

optionally substituted by one or more oxa, thio or azas substituents, and in which one or more hydrogen atoms are optionally replaced by a halogen atom in a ratio of 0 to 100%, and which may possibly be part of a polymer chain; Y is C, SO, S = NCN, S = C (CN) ₂ , POR ¹¹ , P (NCN) R ⁿ , P (C (CN) ₂ R ⁿ , an alkyl, alkenyl, aryl, arylalkyl , Alkylaryl, arylalkenyl, alkenylaryl groups which have 1 to 18 carbon atoms and are optionally substituted by one or more oxa, thio or aza substituents; and a dialkylamino group N (R ¹⁰ ) ² ; - Z ¹ to Z ³ are independently R ¹¹ , R ^{n is} O or CN, which group may optionally be part of a polymer chain The ionic liquids are advantageously preparable easily by ion exchange in water, and these salts advantageously have a good stability to oxidation The advantage of the ionic compounds is the lower cost of the starting anions The low volatility of the ionic liquids, the thermal and electrochemical stability, and the increased conductivity are particularly advantageous for use as solvents in electrochemical Z. ellen, which are operated at low and in particular also higher temperature. In particular, this can reduce the flammability risk of conventional organic solvents.

In preferred embodiments, the cation of the ionic liquid is selected from the group comprising alkylammonium, pyridinium, pyrazolium, pyrrolium,

Pyrrolinium, phosphonium, piperidinium, pyrrolidinium, imidazolium and / or

Sulfonium.

Preferably, the cation of the ionic liquid is selected from the group consisting of l-ethyl-3-methylimidazolium (EMI ^+), l, 2-dimethyl-3-propylimidazolium (DMPI ^+), 1,2-diethyl-3,5-dimethylimidazolium ( DEDMI ⁺ ), trimethyl-n-hexylammonium (TMHA ⁺ ), N-alkyl-N-methylpiperidinium (PIP _RR ⁺ ), N-alkyl-N-methylmorpholinium (MORP _R - _R ) and / or N-alkyl-N-methylpyrrolidinium (PYR _RR ⁺ ). The cation of the ionic liquid is preferred selected from the group comprising pyrrolidinium and / or pyrrolidinium compounds. The cation of the ionic liquid is particularly preferably selected from the group comprising N-alkyl-N-alkylpyrrolidinium (PYR _RR ⁺ ), in particular N-butyl-N-methylpyrrolidinium (PYR ₁₄ ) and / or N-methyl-N-propylpyrrolidinium (PYR ₁₃ ). N-alkyl-N-alkylpyrrolidinium cations have the advantage that these cations are liquid at room temperature. In particular, N-alkyl-N-alkylpyrrolidinium cations can show good results in terms of the function of a cell.

In preferred embodiments, the anion of the ionic liquid is selected from the group comprising halides, cyanides, borates, in particular tetrafluoroborates,

Perfluoroalkyl borates, nitrates, sulfates, alkyl sulfates, aryl sulfates, perfluoroalkyl sulfates,

Sulfonates, alkyl and arylsulfonates, perfluorinated alkylsulfonates, arylsulfonates, phosphates, in particular hexafluorophosphates, perfluoroalkylphosphates, bis (perfluoroalkylsulfonyl) amides, bis (fluorosulfonyl) imides, bis (perfluoroalkylsulfonyl) imides, such as bis (trifluoromethylsulfonyl) imide and / or fluoroalkylsulfonylacetamides.

Preferably, the anion of the ionic liquid is selected from the group comprising bis (trifluoromethanesulfonyl) imide (TFSI), bis (pentafluoroethanesulfonyl) imide (BETT),

Bis (fluorosulfonyl) imide (FST), 2,2,2-trifluoro-N- (trifluoromethanesulfonyl) acetamide (TSAC), tetrafluoroborate (BF ₄ ^~ ), pentafluoroethane trifluoroborate (C ₂ F ₅ BF ₃ ), hexafluorophosphate (PF ₆ ^~ ) , Bisoxolato borate (BOB), difluoro (oxalato) borate (DFOB) and / or

Tri (pentafluoroethane) trifluorophosphate ((C ₂ F ₅ ) ₃ PF ₃ ^~ ). The anion of the ionic liquid is particularly preferably selected from the group comprising bis (trifluoromethanesulfonyl) imide (TFSI), bis (fluorosulfonyl) imide (FSI), bisoxolatoborate (BOB) and / or hexafluorophosphate (PF ₆ ^~ ). These anions have the advantage that they are stable on the cathode and can show good results in terms of cell function. In particular, it is of great advantage if the anion of the ionic liquid corresponds to the anion of the conductive salt. This increases the availability of the anion for incorporation into the electrode. Preferably, the solvent of the electrolyte is an ionic liquid. In

In preferred embodiments, the solvent is an ionic liquid comprising a cation selected from the group comprising pyrrolidinium and / or

Pyrrolidiniumverbindungen, preferably an N-alkyl-N-alkylpyrrolidinium (PYR _R - _R ), in particular N-butyl-N-methylpyrrolidinium (PYRi ₄ ) and / or N-methyl-N-propylpyrrolidinium (PYRi ₃ ⁺ ) and an anion selected from comprising the group

Bis (trifluoromethanesulfonyl) imide (TFSL), bis (pentafluoroethanesulfonyl) imide (BED),

Bis (fluorosulfonyl) imide (FSL), 2,2,2-trifluoro-N- (trifluoromethanesulfonyl) acetamide (TSAC), tetrafluoroborate (BF ₄ ^~ ), pentafluoroethane trifluoroborate (C ₂ F ₅ BF ₃ ), hexafluorophosphate (PF ₆ ^~ ) , Bisoxalatoborat (BOB), Difluoro (oxalato) borate (DFOB) and / or

Tri (pentafluoroethane) trifluorophosphate ((C ₂ F ₅ ) ₃ PF ₃ ^~ ), preferably selected from the group comprising bis (trifluoromethanesulfonyl) imide (TFSL), bis (fluorosulfonyl) imide (FSL),

Bisoxalatoborate (BOB) and / or hexafluorophosphate (PF ₆ ^~ ).

It is particularly advantageous that these ionic liquids dissolve metal salts, especially lithium salts, well and can give very conductive solutions. Furthermore, these are ionic liquids or their mixtures with other metallic salts

excellent solvents for a large number of polymers.

The electrolyte may further contain polymers in addition to the conductive salt and the solvent. In particular, mixtures of an ionic liquid and an organic solvent as well as a polymer can form good gel polymer electrolytes. Preferred polymers are selected from the group comprising homopolymers or copolymers of polyethylene oxide (PEO), polypropylene oxide (PPO), polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), polyacrylonitrile (PAN),

Polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), polyvinyl acetate (PVAc), polyvinyl chloride (PVC), polyphosphazenes, polysiloxanes, polyvinyl alcohol (PVA) and / or homo and (block) copolymers comprising functional side chains selected from the group comprising ethylene oxide, propylene oxide , Acrylonitrile and / or siloxanes.

In a very preferred embodiment, the solvent is an ionic liquid selected from the group comprising bis (trifluoromethanesulfonyl) imide (EMI-TFSI), N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide (PYR ₁₄ TFSI), N-methyl-N- propylpyrrolidinium bis (fluorosulfonyl) imide (PYR ₁ 3FSI) and / or N-methyl-N-propylpyrrolidinium bis (trifluoromethanesulfonyl imide (PYR ₁₃ TFSI)) The electrolyte may contain an ionic liquid or a mixture of an ionic liquid and an organic solvent.

Mixtures of ionic liquids and organic solvents may be higher

Conductivities and lower melting points than pure ionic liquids. Furthermore, properties such as viscosity or the melting point can be influenced in a targeted manner by mixing with an organic solvent.

In preferred embodiments, the organic solvent is selected from the group comprising aliphatic hydrocarbons, in particular pentane, aromatic hydrocarbons, in particular toluene, alkenes, in particular hexene, alkynes, in particular heptin, halogenated hydrocarbons, in particular chloroform or fluoromethane, alcohols, in particular ethanol, glycols, in particular ethylene glycol and diethylene glycol, ethers, in particular diethyl ether and tetrahydrofuran, esters, especially ethyl acetate, Carbonates, in particular diethyl carbonate, lactones, in particular gamma-butyrolactone and gamma-valero lactone, acetates, in particular sodium acetate, sulfones, in particular sulfolane, sulfoxides, in particular dimethyl sulfoxide, amides in particular

Acetic acid (trimethylsilyl) amide, nitriles, in particular acetonitrile, amines in particular

Dimethylamine, ketones, in particular acetone, aldehydes, in particular hexanal, sulfides, in particular carbon disulfide, carbonic acid esters, in particular dimethyl carbonate and ethylene carbonate, carboxylic acids, in particular formic acid, and / or urea derivatives, in particular dimethylpropyleneurea. The organic solvents can advantageously promote a good degree of dissociation of the conductive salt in the electrolyte. It is advantageous that the conductive salt, for example LiTFSI, is dissolved as completely as possible in the electrolyte. As a result, an electrolytic solution having high conductivity and high ion concentration can be provided.

In preferred embodiments, the organic solvent is selected from the group comprising ethylene carbonate, fluoroethylene carbonate, propylene carbonate,

Diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, acetonitrile, glutaronitrile,

Adiponitrile, pimelonitrile, fluoroethylene carbonate, gamma-butyrolactone, gamma-valerolactone, dimethoxyethane, dimethylsulfoxide, vinylene carbonate, vinylmethylene carbonate, 1,3-dioxalane, methyl acetate and / or mixtures thereof. Preferred organic solvents are organic carbonates and mixtures of organic carbonates. The organic solvent is particularly preferably selected from the group comprising ethylene carbonate, diethyl carbonate, dimethyl carbonate, vinylene carbonate and / or mixtures thereof.

Ethylene carbonate is also named l, 3-dioxolan-2-one according to the IUP AC nomenclature. It is advantageous that ethylene carbonate enables high conductivity and good salt dissociation. Organic carbonates and mixtures of organic carbonates as solvents can advantageously a very high conductivity of the electrolyte solution for

Make available. The respective cations or anions reversibly receiving and donating electrodes may be composite electrodes, which may contain binders and additives in addition to the respective cation or anion reversible receiving and donating material. These electrode materials are usually applied to a metal foil or a carbon-based current collector foil, which acts as a current conductor. The cation or anion reversible receiving and donating electrode material is commonly referred to as

Active material.

The positive electrode, the cathode, in particular the secondary electrochemical cell can absorb and release anions reversibly.

In the cells of the invention, the positive electrode preferably comprises one

Intercalation compound into which the anion can be stored. In particular, carbon or metal compounds are particularly alkali, alkaline earth or

Transition metal compounds such as oxides, halides, phosphates, chalcogenides such as sulfides and selenides, silicates, aluminates or hydroxides. These compounds, in particular aluminates and hydroxides, are often layered compounds which can incorporate anions between the layers.

In preferred embodiments, the anion is a reversibly accepting and donating electrode material selected from the group comprising

Carbon, graphite, graphene, or carbon nanotubes,

fluorinated carbons of the formula (CF _x ) _n where x is in the range of 0.01 to 1.24 and n is in the range of 1 to 1000, Carbon oxides of the formula (CO _y ) _m , which are solid at room temperature and where y is in the range of 0.01 to 1 and m is in the range of 1 to 100,

Sulfides M _z S _y of transition metals M selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn, W and / or Al, wherein y is in the range of 1 to 10 and z is in the range of 1 to 3,

Selenide M _z Se _y of transition metals M selected from the group comprising Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn and / or Al, wherein y im Range is from 1 to 10 and z ranges from 1 to 3,

Telluride M _z Te _y of transition metals M selected from the group comprising Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn and / or Al, where y im Range is from 1 to 10 and z ranges from 1 to 3,

complex halides of metals selected from the group comprising Na, Mg, Al, Si, P, S, K, Ca, Ti, Zn, Cu, Ni, Co, Fe, Mn, Cr, V, Zr, Nb, Mo and / or Sn, anion-introducing metal oxides of the transition metals, preferably selected from the group comprising W, Mo, Cr, V and / or Ti,

Metal silicates of the formula Me _n [(Si _x O _y ) ^{4x "2y} ], wherein Me is selected from the group consisting of Fe, Li, Ni, Ti, Na, K, Ba, Ca, Mg, Mn, Co, Al , Sn, Ag, Au, Cu and / or Sb, and 1 <x <65, 1 <y <130 and 1 <n <12, where Si can be replaced by Al up to a ratio of 1: 1,

Metal aluminates of the formula (MeAl (OH) _x ), wherein Me is selected from the group consisting of Fe, Li, Ni, Ti, Na, K, Ba, Ca, Mg, Mn, Co, Al, Sn, Ag, Au , Cu and / or Sb and 2 <x <7, and / or

Layered, mixed metal hydroxides corresponding essentially to the general formula: M _m DdT (OH) _{(3 + m +} d ₎ , wherein

M is a metal cation selected from the group of alkaline earth metals and alkali metals, preferably Li, Na, Mg, Ca, and / or K, particularly preferably Li and Ca and particularly preferably Ca, and m is in the range from 0 to 8, D is at least one divalent metal cation selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu and / or Zn, and d is in the range of 0 to 8,

T is a unit amount of at least one trivalent metal cation selected from the group comprising Al, Ga, Fe and / or Cr, and

(3 + m + d) corresponds to the number of OH groups which are essentially the

Satisfies valency requirements of M, D and T, where m + d is not equal to zero.

Preferably, the anions are carbon-based reversibly receiving and donating electrode material. For the purposes of the present invention, the term "carbon-based" includes carbon-rich or -rich materials such as graphite, pitch or tar,

Pitch coal, coke, synthetic graphite, soot, lamellar graphite, or mixtures thereof.

Preferably, the anions are reversibly receiving and donating electrode material formed of a material selected from the group comprising carbon, graphite, graphene or carbon nanotubes. Carbon and graphite have particularly good intercalating and deintercalating properties for anions.

The anions from the electrolyte may intercalate between the layer lattice planes of the graphite and / or deposit or intercalate with graphite layers of disordered carbons. Carbon materials are particularly well suited if they have a partial graphitic structure. But even porous carbon-rich material can intercalate reversible anions within its crystal lattice. The intercalating carbons or graphites preferably intercalate the anions without their solvation sheath.

In particular, used in the technical processing of carbon fibers such as carbon black, activated carbon, amorphous carbon, carbon fibers, graphites, graphene, Graphite oxides, as well as carbon nanotubes, carbon nanofoam, amorphous carbon or mixtures thereof.

Carbon particles may be amorphous, crystalline or partially crystalline. In particular, amorphous or partially crystalline carbon so-called soft or hard carbons are preferred

usable. Examples of amorphous carbon are, for example, Ketjenblack,

Acetylene black or carbon black. Preference is given to using crystalline

Carbon modifications, for example graphite, carbon nanotubes, so-called carbon nanotubes, as well as fullerenes or mixtures thereof. Also preferably usable as crystalline carbon modifications is so-called VGCF carbon (vapor grown carbon fibers).

Further preferably usable are temperature-treated carbons such as graphene oxides. A heat treatment of carbonaceous or -rich materials increases their

Crystallinity and may increase the ability to store anions. Temperature treated carbons are preferably solid at room temperature. Also preferred are graphene, graphite and / or partially graphitized carbons. Graphite and partially graphitized carbons are particularly good at intercalating anions between the layer lattice planes of the graphite.

Useful graphite or carbon particles preferably have a middle one

Diameter in the range of> 2 nm to <50 μιη, preferably in the range of> 10 nm to <30 μιη, more preferably in the range of> 30 nm to <30 μιη, on. Useful are discrete particles, for example in the form of spheres, such as spheroidal graphite, flakes, grains or rods, so-called nanotubes. The graphite or

Carbon material is particularly useful in powder form. In particular, powdery Carbon and graphite can be easily processed into a composite electrode with a binder.

The electrodes are usually composite electrodes, which in addition to the respective ions reversibly receiving and donating or intercalating and deintercalating

Materials Binder and additives may contain. These electrode materials are usually applied to a metal foil or a carbon-based current collector foil, which acts as a current conductor. Typical further constituents of an electrode are, in addition to the anions or cations, reversible receiving and donating electrode or active material additives and binders. The total weight of the electrode therefore includes the anion or cation reversibly receiving and donating electrode material and further additive and / or binder.

Suitable binders include, for example, polytetrafluoroethylene (PTFE), polyvinylidene difluoride-hexafluoropropylene copolymer (PVDF-HFP), styrene-butadiene elastomer (SBR),

Carboxymethylcelluloses (CMC), in particular sodium carboxymethylcellulose (Na-CMC), or polyvinylidene difluoride (PVDF). Suitable additives are in particular

Conductivity additives such as metal particles, such as copper particles, in particular

Metal particles with a size in the nanometer range, as well as conductive carbon materials, in particular carbon blacks, carbon fibers, graphites, carbon nanotubes or mixtures thereof. Suitable carbon blacks are, for example, the finely divided industrial carbon blacks known by the name carbon black.

Preferably, the anions comprise reversibly intercalating and deintercalating electrode carbon and / or graphite in the range of> 70 wt .-% to <100 wt .-%, preferably in the range of> 80 wt .-% to <98 wt .-%, preferably in the range of> 90% by weight to < 97 wt .-%, based on the total weight of the electrode. The proportion of> 70% by weight of the electrode formed in a dual intercalation cell of the carbon and / or graphite anion intercalation compound makes a significant difference to conventional lithium ion battery cathodes containing carbon and graphite as an additive contained only in small amounts of about 10 wt .-%.

Other useful carbon compounds are fluorinated carbons of the formula (CF _x ) _n where x is in the range of 0.01 to 1.24 and n is in the range of 1 to 1000 and carbon oxides of the formula (CO _y ) _m which are solid at room temperature and y is in the range of 0.01 to 1 and m is in the range of 1 to 100. An example of fluorinated carbons is LiCF _x . An example of suitable carbon oxides are temperature- and oxygen-treated graphites.

Another group of advantageously usable anions reversibly accepting and donating compounds are transition metal chalcogenides. Preference is given to sulfides,

Selenides and tellurides of the formula M _z S _y, M _z Se _y, and M _z Te _y of transition metals M selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr , Nb, Mo,

Sn, W and / or Al, where y is in the range of 1 to 10 and z is in the range of 1 to 3.

Preferred transition metals M are selected from the group comprising Ti, V, Cr, Ni and / or Mo. Sulfides such as TiS ₂ and NiS are particularly advantageous. Particularly advantageously usable are TaS ₂ , TiS ₂ , MoS ₂ and WS ₂ . Also usable are selenides like

TiSe ₂ .

Also preferably usable are complex halides of metals selected from the group consisting of Na, Mg, Al, Si, P, S, K, Ca, Ti, Zn, Cu, Ni, Co, Fe, Mn, Cr, V, Zr, Nb , Mo and / or Sn. For the purposes of the present invention, the term "complex halides" is to be understood as meaning compounds in which the halides are present as complexing ligands In particular, the complex halides are insoluble in the electrolyte and are solid at room temperature (20 ± 2 ° C). Examples of preferably usable complex halides are selected from the group comprising chiolith (Na ₅ Al ₃ Fi ₄ ), usovite (Ba ₂ CaMgAl ₂ Fi ₄ ) and / or cryptophalite ((NH ₄ ) ₂ SiF ₆ ). Further particularly useful compounds are anion-donating metal oxides of the transition metals, preferably of transition metals selected from the group comprising W, Mo, Cr, V and / or Ti. Particular preference is given to using metal oxides selected from the group comprising MoO, MoO ₂ , Ti0 ₂ and / or W0 ₂ . Also useful compounds are in particular layered metal silicates of the formula Me _n [(Si _x O _y ) ^{4x "2y} ], where Me is selected from the group consisting of Fe, Li, Ni, Ti, Na, K, Ba, Ca, Mg, Mn, Co, Al, Sn, Ag, Au, Cu and / or Sb, 1 <n <12 and 1 <x <65 and 1 <y <130. In the case of the metal silicates of the formula Me "[(Si _x O _y ) ^{4x 2y} ] can Si up to one

Ratio of 1: 1 to be replaced by AI. Preferred metals Me are selected from the group comprising Li, Na, Ca, Ba and / or Fe, in particular Li, Na and Fe. Metal silicates selected from the group consisting of Li ₂ FeSiO ₄ , Li ₂ CoSiO ₄ , Li ₂ MnSiO ₄ and / or NaFeSi ₄ are particularly advantageously usable.

Further usable compounds are, in particular, layered metal aluminates of the formula (MeAl (OH) _x ) where Me is selected from the group consisting of Fe, Li, Ni, Ti, Na, K, Ba, Ca, Mg, Mn, Co, Al, Sn, Ag, Au, Cu and / or Sb and 2 <x <7. Preference is given to NaAl (OH) ₄ and KAl (OH) ₄ .

Further usable compounds are, in particular, layered metal hydroxides corresponding essentially to the general formula M _m DdT (OH) _{(3 + m +} d ₎ , where M is a metal cation selected from the group of alkaline earth metals and alkali metals, and m is in the range from 0 to 8 D is at least one divalent metal cation selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu and / or Zn, and d is in the range of 0 to 8, T is a unit amount of at least one trivalent metal cation selected from the group comprising Al, Ga, Fe and / or Cr, and (3 + m + d) corresponds to the number of OH groups satisfying substantially the valence requirements of M, D and T. where m + d is not equal to zero.

These metal hydroxides are also referred to as "mixed" metal hydroxides due to the various metal cations M, D and T. The term "substantially" has in the context of the present invention with respect to the general formula M _m DdT (OH) _{(3 + m +} d ₎ the meaning that the sum of the valences of the electropositive and electronegative elements equalize.

Preference is given to metal hydroxides of alkaline earth metals and alkali metals selected from the group comprising Li, Na, Mg, Ca and / or K, more preferably of lithium and / or calcium and particularly preferably of calcium. A further preferred metal hydroxide is [Mg _d Al (OH) ₃₊ d] where d is between 0.5 and 4.

The negative electrode, the anode, in particular the secondary electrochemical cell can absorb and release cations reversibly. The cations are in particular the cations of the conductive salt of the electrolyte. Preferred cations are lithium and

Sodium cations, especially lithium cations.

In the cells of the invention, the negative electrode is preferably one

Intercalation compound into which the cation can be stored. In particular, carbon compounds, metals and metal alloys, or metal compounds, in particular alkali, alkaline earth or transition metal compounds such as alkali and

Erdalkalimetalli titanate. In preferred embodiments, the cations, preferably lithium and sodium cations, in particular lithium cations, reversibly receiving and donating electrode material is selected from the group comprising

Carbon, in particular amorphous or semi-crystalline carbon particles, graphites, graphenes,

fluorinated carbons of the formula (CF _x ) _n where x is in the range of 0.01 to 1.24 and n is in the range of 1 to 1000,

Metals and metal alloys of metals selected from the group consisting of Li, Ni, Ti, Na, K, Ba, Ca, Mg, Ga, Ge, In, V, Si, Al, Sn, Ag, Au, Cu and / or Sb , - phosphides of the formula M _k P _x with P _x ^{k ~} or P _x ^{(x + 2) ~} , where 1 <x <8 and 1 <k <7, where

M is selected from the group of the alkali metals, alkaline earth metals and transition metals, metal oxides of the transition metals, preferably selected from the group comprising W, Mo, Cr, V and / or Ti,

Sulfides M _z S _y of transition metals M selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn, W and / or Al where y in the

Range is from 1 to 10 and z ranges from 1 to 3,

Metal fluorides with one or more metals selected from the group consisting of Fe, Cr, Nb, Rh, Ag, Au, Se, Co, Te, Ni, Cu, V, Mo, Pb, Sb, Bi and / or Si,

- Alkali and alkaline earth metal titanates having the formula A _x Ti _y 0 ₄ or ΕΑο _ι5χ Ti _y 0 ₄ , wherein 0.8 <x <1, 4 and 1, 6 <y <2.2, and / or

- Alkali and alkaline earth metal cuprates of the formulas A _x Cu _y 0 ₂ or EA _x / ₂ Cu _y 0 ₂ , wherein 0.8 <x <1.2 and 0.7 <y <1.25.

Preferably, the cation reversibly receiving and donating electrode material is carbon-based, for example, a carbonaceous material such as graphite, pitch or tar, pitch coal, coke, synthetic graphite, soot, lamellar graphite, or mixtures thereof to understand. Preferably, the cation is reversibly receiving and donating electrode material formed of a material selected from the group comprising carbon, in particular amorphous, crystalline or partially crystalline carbon particles, graphites and graphenes.

Carbon materials are particularly well suited if they have a partial graphitic structure, but also porous carbonaceous material is suitable. In particular, used in the technical processing of carbon fibers such as carbon black, activated carbon, amorphous carbon, carbon fibers, graphites, graphene,

Graphite oxides, as well as carbon nanotubes, carbon nanofoam, amorphous carbon or mixtures thereof.

usable. Examples of amorphous carbon are, for example, Ketjenblack,

Acetylene black or carbon black. Preference is given to using crystalline

Crystallinity and may increase the ability to store cations. Temperature treated carbons are preferably solid at room temperature. Also preferred are graphene, graphite and / or partially graphitized carbons. Graphite and partially graphitized carbons are particularly good at intercalating cations between the lattice planes of the graphite. Useful graphite or carbon particles preferably have a middle one

Diameter in the range of> 2 nm to <50 μιη, preferably in the range of> 10 nm to <30 μιη, more preferably in the range of> 30 nm to <30 microns, on.

Useful are discrete particles, for example in the form of spheres, such as spheroidal graphite, flakes, grains or rods, so-called nanotubes. The graphite or

Carbon material is particularly useful in powder form. In particular, powdered carbon and graphite can be well processed with a binder into a composite electrode.

Preferably, the cations, especially lithium cations, reversibly accepting and donating electrode material is carbon based. Preferably, the cation comprises reversibly intercalating and deintercalating electrode carbon and / or graphite in the range of> 70 wt .-% to <100 wt .-%, preferably in the range of> 80 wt .-% to <98 wt .-%, preferably in the range of> 90 wt .-% to <97 wt .-%, based on the total weight of the electrode.

Other useful carbon compounds are fluorinated carbons of the formula (CF _x ) _n where x is in the range of 0.01 to 1.24 and n is in the range of 1 to 1000.

Also particularly advantageous metals and metal alloys of metals selected from the group consisting of Li, Ni, Ti, Na, K, Ba, Ca, Mg, Ga, Ge, In, V, Si, Al, Sn, Ag, Au, Cu and / or Sb. In particular, metals and metal alloys of metals selected from the group consisting of Li, Si and / or Sn are preferred. Particularly preferred are lithium and silicon and their metal alloys. In particular, electrodes are preferably formed of Li, Si or Sn, in particular lithium or silicon are well suited, cations such as lithium or

To store and transfer potassium cations. In particular, lithium metal or

Lithium metal alloys are well suited in conjunction with a lithium conducting salt.

Also usable are phosphides of the formula M _k P _x with P _x ^{k "} or P _x ^{(x + 2)"} , where 1 <x <8 and 1 <k <7, where M is selected from the group of alkali, alkaline earth - and

Transition metals. Preferred alkali metals, alkaline earth metals and transition metals are selected from the group comprising Li, Na, Mg, Ca, K, Cu and / or Zn. Particular preference is given to copper and tin.

Further particularly useful compounds are metal oxides of the transition metals, preferably of transition metals selected from the group comprising W, Mo, Cr, V and / or Ti. Particularly preferred are metal oxides selected from the group comprising MoO, Mo0 ₂ , Ti0 ₂ and / or W0 ₂ .

Another group of compounds which can be used advantageously are sulfides of the formula M _z S _y of transition metals M selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo , Sn, W and / or AI wherein y is in the range of 1 to 10 and z is in the range of 1 to 3. Preferred transition metals M are selected from the group comprising Ti, V, Ni, Cr, Mn and / or Mo, particularly preferably Ti and Mo.

Also preferably usable are metal fluorides and complex metal fluorides with one or more metals selected from the group consisting of Fe, Cr, Nb, Rh, Ag, Au, Se, Co, Te, Ni, Cu, V, Mo, Pb, Sb, Bi and / or Si. For the purposes of the present invention, the term "complex metal fluorides" is to be understood as meaning compounds in which the fluorides are present as complex ligands In particular, the complex fluorides are insoluble in the electrolyte and are solid at room temperature (20 ± 2 ° C.) Metal fluorides of metals selected from the group comprising Cu, Bi and / or Fe, particularly preferred are CuF ₂ and BiF ₃ .

Further preferred cations, preferably lithium and sodium cations, in particular lithium cations, reversibly absorbing and donating electrode materials are alkali metal (A) and alkaline earth metal (EA) titanates of the formula A _x Ti _y 0 ₄ or EAo _i 5 _X Ti _y 0 ₄ , where 0.8 <x <1.4 and 1.6 <y <2.2. Titaniumates of the elements Na and Li are preferred, and lithium titanate Li ₄ TisOi ₂ is particularly preferred. In particular, lithium titanate is particularly suitable for the intercalation of lithium ions. Furthermore, lithium titanate can provide a shallow charge / discharge potential level.

Further preferred cations, preferably lithium and sodium cations, in particular lithium cations, reversibly absorbing and donating electrode materials are alkali (A) and alkaline earth metal (EA) cuprates of the formulas A _x Cu _y O ₂ or

where 0.8 <x <1.2 and 0.7 <y <1.25.

In preferred embodiments, the cation, particularly lithium cations, reversibly accepting and donating electrode material is useful at a potential in the range of 0.7V to 2.2V versus lithium. This is particularly advantageous if the conductive salt is a lithium salt. Preferably, the cation, in particular lithium cations, reversibly receiving and donating electrode material is selected from the group comprising Ti0 ₂ , W0 ₂ , Mo0 ₂ and / or Li ₄ Ti ₅ 0i ₂ . Advantageously, the potential of cation incorporation and removal is above the thermodynamic stability window of various organic solvents. In particular, an electrochemical cell can be operated particularly safely using these electrode materials.

Preferably, the cation comprises reversibly receiving and donating electrode as the electrode material, a metal oxide selected from the group comprising Ti0 ₂ , W0 ₂ , Mo0 _2nd and / or Li ₄ Ti ₅ 0i ₂ in the range of> 50 wt .-% to <98 wt .-%, preferably in the range of> 70 wt .-% to <95 wt .-%, preferably in the range of> 80 % By weight to <95% by weight, based on the total weight of the electrode. Preferred is a particularly secondary electrochemical cell comprising a cation reversibly receiving and donating electrode comprising carbon in particular graphite in the range of> 70 wt .-% to <100 wt .-%, and anions reversibly receiving and donating electrode comprising carbon in particular graphite in the range from> 70 wt .-% to <100 wt .-% or Li ₄ Ti ₅ 0i ₂ in the range of> 50 wt .-% to <98 wt .-%, each based on the total weight of the electrode. In particular, by using graphite as the cathode and anode is advantageously the

Environmental friendliness of the cell higher and the cost of the cathode material lower than in classical systems. Particularly preferred is a, in particular secondary, electrochemical cell comprising a cation, in particular lithium cations, reversibly receiving and donating electrode comprising carbon, in particular graphite in the range of> 70 wt .-% to <100 wt .-% or Li ₄ Ti ₅ 0i ₂ im Range of> 50 wt .-% to <98 wt .-% and anions reversibly receiving and donating electrode comprising carbon in particular graphite in the range of> 70 wt .-% to <100 wt .-%, each based on the

Total weight of the electrode. Lithium titanate is particularly good for intercalating

Lithium cations suitable.

Further preferred is a, in particular secondary, electrochemical cell comprising a cation, in particular lithium cations, reversibly receiving and donating electrode comprising lithium metal and anions reversibly receiving and donating

Electrode comprising carbon, in particular graphite in the range of> 70 wt .-% to <100 wt .-%, based on the total weight of the electrode. Further preferred is one, in particular secondary, electrochemical cell comprising lithium metal as cations, in particular lithium cations, reversibly receiving and donating electrode and anion reversibly receiving and donating electrode comprising

Transition metal sulfides, in particular TaS ₂ , TiS ₂ , MoS ₂ and WS ₂ .

Suitable conductive salts are salts of metals selected from the group consisting of Li, Na, K, Ba, Mg, Ca, Al and / or B, or compounds in which the anion of the conductive salt is present with H ⁺ as counterion. Suitable conductive salts are, for example, salts of barium, magnesium or calcium selected from the group comprising YF ₂ , YCl ₂ , YBr ₂ , YI ₂ , Y (PF ₆ ) ₂ , Y (AsF ₆ ) ₂ , Y (C 10 ₄ ) ₂ , Y (N0 ₃ ) ₂ , Y (SO ₄ ), Y (SbF ₆ ) ₂ , Y (PtCl 6) ₂ , Y (CN) ₂ , Y ((CF ₃ ) SO ₃ ) ₂ (YTf ₂ ), Y (C ( S0 ₂ CF ₃₎ ₃₎ _2, Y (PF ₃ (CF ₃₎ ₃₎ ₂ (YFAP _2), Y / PF ₄ (C ₂ 0 ₄₎₎ ₂ (YTFOB _2), Y (BF ₄₎ _2, Y (B (C ₂ O ₄ ) ₂ ) ₂ (YBOB ₂ ), Y (BF ₂ (C ₂ O ₄ )) ₂ (YDFOB ₂ ), Y (B (C ₂ O ₄ ) (C ₃ O ₄ )) ₂ (YMOB ₂ ), Y ((C ₂ F ₅ BF ₃ )) ₂ (YFAB ₂ ), YB ₁₂ F ₁₂ (YDFB), Y (N (S0 ₂ F) ₂ ) ₂ (YFSI ₂ ), Y (N ( S0 ₂ CF ₃ ) ₂ ) ₂ (YTFSI ₂ ) and / or Y (N (S0 ₂ C ₂ F ₅ ) ₂ ) ₂ (YBETI ₂ ), wherein Y is selected from the group consisting of Ba, Mg and Ca.

Further suitable conductive salts are salts of aluminum or boron selected from the group consisting of XF ₃ , XCl ₃ , XBr ₃ , XI ₃ , X (PF ₆ ) ₃ , X (AsF ₆ ), X (C 10 ₄ ) ₃ , X (SbF ₆ ) _3, X (N0 ₃₎ _3, X ₂ (S0 ₄₎ _3, X (PtCl ₆₎ _3, X (CN) _3, X ((CF ₃₎ S0 ₃₎ ₃ (XTF _3), X (C ( S0 ₂ CF ₃₎ ₃₎ _3, X (PF ₃ (CF ₃₎ ₃₎ ₃ (XFAP ₃₎

X / PF ₄ (C ₂ O ₄ )) ₃ (XTFOB ₃ ), X (BF ₄ ) ₃ , X (B (C ₂ O ₄ ) ₂ ) ₃ (XBOB ₃ ), X (BF ₂ (C ₂ O ₄ )) ₃ (XDFOB ₃ ), X (B (C ₂ O ₄ ) (C ₃ O ₄ )) ₃ (XMOB ₃ ), X ((C ₂ F ₅ BF ₃ )) ₃ (XFAB ₃ ), XB ₁₂ F ₁₂ (XDFB), X (N (S0 ₂ F) ₂₎ ₃ (XFSI _3), X (N (S0 ₂ CF ₃₎ ₂₎ ₃ (XTFSI ₃₎ and / or X (N (S0 ₂ C ₂ F ₅ ) ₂ ) ₃ (XBETI ₃ ), wherein X is selected from the group comprising AI and / or B.

In preferred embodiments, the conductive salt is selected from the group consisting of ZF, ZCl, ZBr, ZI, ZPF ₆ , ZAsF ₆ , ZC 10 ₄ , ZNO ₃ , Z ₂ SO ₄ , ZSbF ₆ , ZPtCl, ZCN, Z (CF ₃ ) SO ₃ (ZTf), ZC (SO ₂ CF ₃ ) ₃ , ZPF ₃ (CF ₃ ) ₃ (ZFAP), ZPF ₄ (C ₂ O ₄ ) (ZTFOB), ZBF ₄ , ZB (C ₂ O ₄ ) ₂ (ZBOB) . ZBF ₂ (C ₂ O ₄ ) (ZDFOB), ZB (C ₂ O ₄ ) (C ₃ O ₄ ) (ZMOB), Z (C ₂ F ₅ BF ₃ ) (ZFAB), Z ₂ B ₁₂ F ₁₂ (ZDFB ), ZN (SO ₂ F) ₂ (ZFSI), ZN (SO ₂ CF ₃ ) ₂ (ZTFSI) and / or ZN (SO ₂ C ₂ F ₅ ) ₂ (ZBETI), wherein Z is selected from the group comprising Li , Na, K and / or H. Preferred conductive salts are salts of lithium, sodium or potassium. In particular, lithium ions are due to their small size well suited to be stored in electrodes and outsourced. Further, for lithium, a wide variety of electrode materials are usable in the electrochemical system of the present invention.

Preferably, the conductive salt is selected from the group comprising ZPF ₆ , ZN (SO ₂ F) ₂ (ZFSI), ZB (C ₂ O ₄ ) ₂ (ZBOB), and / or ZN (S0 ₂ CF ₃ ) ₂ (ZTFSI) where Z is selected from the group comprising Li, Na and / or H, preferably Li.

Preferably, the conductive salt is a lithium salt. Preferably, the lithium salt is selected from the group consisting of LiPF ₆ , LiAsF ₆ , LiC 10 ₄ , LiSbF ₆ , LiPtC 1, Li (CF ₃ ) SO ₃ (LiTf), LiC (SO ₂ CF ₃ ) ₃ , LiPF ₃ (CF ₃ ) ₃ (LiFAP), LiPF ₄ (C ₂ O ₄ ) (LiTFOB), LiBF ₄ , LiB (C ₂ O ₄ ) ₂ (LiBOB), LiBF ₂ (C ₂ O ₄ ) (LiDFOB), LiB (C ₂ O ₄ ) (C ₃ O ₄ ) (LiMOB), Li (C ₂ F ₅ BF ₃ ) (LiFAB), Li ₂ Bi ₂ Fi ₂ (LiDFB), LiN (S0 ₂ F) ₂ (LiFSI), LiN (S0 ₂ CF ₃ ) ₂ (LiTFSI) and / or LiN (S0 ₂ C ₂ F ₅ ) ₂ (LiBETI), preferably LiPF ₆ . In particular, LiN (S0 ₂ F) ₂ (LiFSI), LiN (S0 ₂ CF ₃ ) ₂ (LiTFSI) and LiB (C ₂ 0 ₄ ) ₂ (LiBOB) can lead to a good capacity and electrochemical cell Temperature resistance has. In particular, LiTFSI has high thermal and electrochemical stability, is non-toxic and insensitive to hydrolysis. The anion of the conducting salt, in particular of the lithium salt, preferably does not decompose to a potential of at least 3.5 V, preferably of at least 4 V, preferably of 5 V, with respect to the potential of lithium. In particular, the anion of the lithium salt preferably does not decompose in a potential range of> 3 V to <6 V, preferably not in a potential range of> 5 V to <5.7 V, compared to the potential of lithium. This is particularly advantageous because dual storage cells are operated at high cell voltages. In preferred embodiments, the inventive electrochemical cell is operated at a cell voltage in the range of> 3 V to <6 V, preferably in the range of> 5 V to <5.7 V, against lithium.

Anions which absorb and donate the anions reversibly receiving and donating electrode are, in particular, the anions comprising the electrolyte, in particular the anions of the lithium salt.

Preferably, the anion is selected from the group consisting of F ^~ , Cl ^~ , Br ^~ , Γ, PF ₆ ^~ , BF ₄ ^" , B (C ₂ 0 ₄ ) ₂ - (BOB), BF ₂ (C ₂ 0 ₄ ) - (DFOB), B (C ₂ O ₄ ) (C ₃ O ₄ ) - (MOB), (C ₂ F ₅ BF ₃ ) ^" (FAB), (CF ₃ ) SO ₃ ^- Bi ₂ Fi ^{2 2"} (DFB) , N (S0 ₂ F) ₂ ^" (FSI), N (S0 ₂ CF ₃ ) ₂ ^" (TFSI) and / or N (S0 ₂ C ₂ F ₅ ) ₂ ^" (LiBETI). The anion is preferably selected from the group comprising PF ₆ ^~, N (S0 ₂ F) ₂ ^~ (FSI), N (S0 ₂ CF ₃₎ ₂ ^"(TFSI) and / or B (C ₂ 0 ₄₎ _^2" ( BOB).

Relatively large anions have the advantage in the electrolyte that they facilitate the path of the ions through the electrolyte due to the lower attractive force. In an advantageous manner, it has been found that large anions such as N (S0 ₂ F) ₂ ^- , N (S0 ₂ CF ₃ ) ₂ ^-, and B (C ₂ 0 ₄ ) ₂ ^{- are incorporated} into the electrode in the dual storage system according to the invention can. This is particularly advantageous, since it was hitherto assumed that only very small or smaller anions such as fluoride, PF ₆ or BF ^~ ₄ ^~ be reversibly intercalated in graphite electrodes. This allows the

electrochemical cell have a further improved capacity and temperature resistance. Preferably, the conductive salt, for example a lithium salt, is dissolved in the solvent. Preferably, the concentration of the lithium salt in the electrolyte is in the range of> 0.5 M to <19 M, preferably in the range of> 0.65 M to <7 M, more preferably in the range of> 1 M to <5 M. Preferably the concentration of the conducting salt, in particular the lithium salt, in particular a lithium salt comprising an organic anion selected from the group comprising B (C ₂ 0 ₄ ) ₂ ^- (BOB), BF ₂ (C ₂ O ₄ ) ^- (DFOB), B (C ₂ 0 ₄ ) (C ₃ O ₄ ) ^" (MOB), (C ₂ F ₅ BF ₃ ) - (FAB), (CF ₃ ) S0 ₃ ^" , B ₁₂ F ₁₂ ² - (DFB), N (S0 ₂ F) ₂ ^" (FSI), N (S0 ₂ CF ₃ ) ₂ ^" (TFSI) and / or N (S0 ₂ C ₂ F ₅ ) ₂ ^" (LiBETI), in the electrolyte in the range of> 0.5 M to < 2.5 M, preferably in the range of> 0.65 M to <2 M, particularly preferably in the range of> 1 M to <1.5 M.

The particular secondary electrochemical cell preferably comprises a conductive salt selected from the group consisting of LiN (SO ₂ F) ₂ (LiFSI), Li (SO ₂ CF ₃ ) ₂ (LiTFSI) and LiB (C ₂ O ₄ ) ₂ (LiBOB) as solvent an ionic liquid comprising a cation selected from the group comprising an N-alkyl-N-alkylpyrrolidinium (PYR _RR ⁺ ), in particular N-butyl-N-methylpyrrolidinium (PYRi ₄ ⁺ ) and / or N-methyl-N-propylpyrrolidinium (PYRi ₃ ⁺ ) and an anion selected from the group comprising

Bis (trifluoromethanesulfonyl) imide (TFSI), bis (fluorosulfonyl) imide (FSI), bisoxolato borate (BOB) and / or hexafluorophosphate (PF ₆ ^~ ).

In particular, in an anionic intercalation-based cell, it is advantageous that the electrolyte used is usable as an active material. Furthermore, it is advantageous if the anion of the ionic liquid corresponds to the anion of the conductive salt. This increases the availability of the anion for incorporation into the electrode.

The electrolyte is preferably admixed with a customary additive. preferred

Aggregates are, for example, metal oxides such as Ti0 _2, A1 ₂ 0 ₃ and Si0 _2, preferably Si0. ₂ Other preferred additives are modified nano-particles, for example commercially available under the trade name Aerosil from Evonik-Degussa.

The electrochemical cell furthermore has in particular a separator. The separator is used for electrical insulation of the two electrodes. Preferably, the separator is disposed between the electrodes. The particularly secondary electrochemical cell preferably comprises a cation reversibly receiving and donating electrode, an anion reversibly receiving and donating electrode, a separator and an electrolyte comprising a lithium salt and a solvent. The separator is permeable to the ions of the electrolyte. The separator may be porous. Suitable materials for the separator are for example microporous plastics, for example poly-ethylene-tetrafluoroethylene, nonwovens made of glass fibers or polyethylene. Preference is given to microporous films, for example porous ethylene-tetrafluoroethylene film or nonwoven fabrics. Nonwovens of glass fibers, in particular nonwoven glass fiber nonwoven, are particularly suitable.

The separator may further be a gel polymer separator. A gel polymer separator can be prepared, for example, by admixing a polymer, in particular selected from the group consisting of polypropylene, polytetrafluoroethylene and / or polyvinylidene difluorides, preferably polyethylene oxides, into the electrolyte.

Another object of the invention relates to the use of an ionic liquid as a solvent in an electrochemical cell, in particular a secondary electrochemical cell, comprising a cation reversibly receiving and donating electrodes, anions reversibly receiving and donating an electrode and a

Electrolytes comprising a conducting salt and a solvent.

The particular secondary electrochemical cell is particularly suitable for a lithium-based energy storage. Another object of the invention relates to Use of an ionic liquid as a solvent in a lithium-based energy storage based on the dual-ion insertion principle. Lithium-based

Energy stores are preferably selected from the group comprising lithium batteries, lithium ion batteries, lithium ion accumulators, lithium polymer batteries and / or lithium ion capacitors, in particular lithium ion batteries or lithium ion accumulators.

Examples and figures which serve to illustrate the present invention are given below.

Here are the figures:

Figure 1 shows the discharge capacity and efficiency of one embodiment of a

electrochemical cell against the number of charge / discharge cycles.

Figure 2 shows the current / voltage curve of the electrochemical cell versus time.

Figure 3 discharge capacity and efficiency of another embodiment of a

electrochemical cell against the number of charge / discharge cycles.

Figure 4 shows the discharge capacity and efficiency of one embodiment of a

electrochemical cell with a graphite and a lithium electrode against a number of 500 charging / discharging cycles.

Figure 5 shows the Entladekapazitäten the embodiment with a graphite and

a lithium electrode at temperatures of 20 ° C, 40 ° C and 60 ° C against the number of charge / discharge cycles.

FIG. 6 shows the voltage curve of the first charge / discharge cycle of FIG

electrochemical cell with a graphite and a lithium electrode at

Temperatures of 20 ° C, 40 ° C and 60 ° C against time.

Figure 7 shows the discharge capacities of electrochemical cells with a graphite and a lithium electrode as a function of that on the x-axis plotted D90 value of the particle size distribution of the graphite used.

example 1

Production of an electrochemical cell

An electrochemical cell with two composite electrodes was produced. For the production of the graphite electrode, based on the total weight of the electrode, 90% by weight of graphite (graphite KS6, TIMCAL®, Bodio, Switzerland), 5% by weight of carbon (Super-P Li, TIMCAL®, Bodio, Switzerland) and, as a binder, 5% by weight sodium carboxymethycellulose (Walocel® CRT 2000 PPA 12, Dow Wolff Cellulosics, The Dow Chemical Company, Midland, MI, USA) in deionized water as a solvent. The mixture was purified using a T25 digital Ultra-Turrax stirrer and a S 25 N-18G

Dispersing tool (both IKA, Staufen, Germany) homogenized at 5000 rpm for 1 hour. The mixture was then applied using a doctor blade on an aluminum foil of a thickness of 20 μιη (99.88% pure, Evonik-Degussa ^® ) as a current collector with a layer thickness of 200 μιη. The electrode was dried at 80 ° C for 12 hours. Subsequently, a round electrode with a diameter of 12 mm, or an area of 1.13 cm ² , punched out and dried for 24 hours at 120 ° C under vacuum. The surface loading was> 2 mg / cm ² . The determination of

Surface loading was carried out by weighing the pure aluminum foil and the punched electrodes.

For the preparation of the lithium titanate electrode, based on the total weight of the electrode, 85% by weight of lithium titanate Li ₄ TisOi ₂ (battery grade / battery grade purity, Südchemie, Munich, Germany), 10% by weight of carbon (Super-P Li TIMCAL®, Bodio, Switzerland) and, as binder, 5% by weight polyvinylidene difluoride (Kynar® Flex 761, Arkema, France) dissolved in N-methyl-2-pyrrolidone (Acros Organics, 99.5%, Extra Dry) as Solvent mixed. The mixture was homogenized at 8000 rpm for 1.5 hours using a T25 digital Ultra-Turrax stirrer and a S 25 N-18 G dispersing tool (both IKA, Staufen, Germany). The mixture was then applied using a doctor blade on an aluminum foil of a thickness of 20 μιη (purity 99.88%, Evonik Degussa) as a current conductor with a layer thickness of 175 μιη. The electrode was dried at 80 ° C for 12 hours. Subsequently, an electrode having a diameter of 12 mm was punched out and dried for 24 hours at 150 ° C under vacuum. The surface loading was> 3 mg / cm ² . The surface load was determined by weighing the pure aluminum foil and the punched electrodes.

The separator used was a glass fiber separator from Whatman (Whatman GF / D, GE Healthcare, Great Britain).

The electrolyte used was the ionic liquid 1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide (Pyri ₄ TFSI) (purity of 99.9%, water content <50 ppm, Solvionic, Toulouse, France), with the lithium source being 0 3 mol / l lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) ("battery grade" grade, 3M, St. Paul, USA) was dissolved in the ionic liquid.

Example 2

Electrochemical investigation of the electrochemical cell

The electrochemical examination of the electrochemical cell prepared according to Example 1 was carried out in a cell made of a modified gas valve of the company

Swagelok ^® with the exclusion of oxygen and water. The potentiostat / galvanostat used was a Maccor 4000 series instrument or a BaSyTec MDS battery test system. The electrodes used in the measuring cell were round with a diameter of 12 mm, respectively an area of 1.13 cm ² . The assembly of the cell was carried out in a glove box filled with an inert gas atmosphere of argon and an oxygen and water content of less than 1 ppm. After this

Assembly, the cell was equilibrated for 24 hours at room temperature (20 ± 2 ° C).

To charge the cell, a galvanostatic current was applied, which corresponded to a specific current density based on the active material of the graphite electrode of 50 mA / g. The cell was charged to a final charge voltage of 3.65 V and then discharged to 1.8 V with the same galvanostatic current, the data in volts being based on the cell voltage between the graphite and lithium titanate electrodes. This charge / discharge process is one cycle and has been repeated 50 times at 20 ± 2 ° C.

During the charging process, the lithium ion from the electrolyte is correspondingly incorporated into the lithium titanate electrode and the TFSI anion into the graphite electrode. In the charged state, the electrolyte is depleted of Li ⁺ and TFSL because they are in the two electrodes as charge carriers. When discharging these ions are returned to the

Electrolytes released and thus increased the ion concentration again. FIG. 1 shows the discharge capacity and the efficiency of the charging / discharging process of the electrochemical cell as a function of the number of cycles applied on the x-axis. In this case, the left y-axis shows the value of the discharge capacity, represented as a black circle, and the right y-axis the efficiency of the charge / discharge, shown as a triangle. Shown are the first 50 load / unload operations.

It was found that the charge / discharge process was more than 99% reversible after the first cycle, based on a maximum efficiency of 100%, and this over the remained constant above 98%. Furthermore, based on the graphite electrode, a discharge capacity of up to 50 mAh / g could be achieved.

This shows that using an ionic liquid a very high efficiency of the cell can be achieved. Furthermore, significantly higher charge and discharge currents could be realized using an ionic liquid than under

Use of organic electrolytes can be achieved.

Figure 2 shows the current / voltage curve of the cell versus that on the x-axis

applied time. The voltage of the cell is shown in full lines on the left y-axis and the current in dashed lines on the right y-axis. Positive currents refer to the charging process, whereas negative currents represent the discharging process. FIG. 2 shows the first 10 charging / discharging operations. It was found that there was no electrolyte decomposition compared to classical organic electrolytes, although the potential of the graphite cathode was higher than 5V vs. 5V. Li / Li ⁺ was. Also, from about the 3rd cycle, the shape of the charge and discharge curves was almost identical, which suggests a high reversibility of storage and retrieval. Example 3

Production of an Electrochemical Cell with Lithium Electrode

An electrochemical cell was fabricated with a composite electrode and a metallic lithium electrode.

The graphite electrode was produced as described in Example 1. For the preparation of the electrode of metallic lithium, a round electrode of a diameter of 12 mm and a thickness of ΙΟΟμιη of a film of metallic Lithium (battery grade / battery grade purity, Chemetall) punched out in a glovebox and used as a counter electrode.

The electrolyte used was the ionic liquid 1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide (Pyri ₄ TFSI) (purity of 99.9%, water content <50 ppm, Solvionic, Toulouse, France), the lithium source being 0 3 mol / l lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) ("battery grade" grade, 3M, St. Paul, USA) was dissolved in the ionic liquid.

Example 4

Electrochemical investigation of the electrochemical cell with lithium electrode

The electrochemical examination of the electrochemical cell prepared according to Example 3 was carried out in a cell made from a modified gas valve of the company

Swagelok ^® with the exclusion of oxygen and water. The potentiostat / galvanostat used was a Maccor 4000 series instrument or a BaSyTec MDS battery test system. The electrodes used in the measuring cell were round with a diameter of 12 mm, respectively an area of 1.13 cm ² .

The assembly of the cell was carried out in a glove box filled with an inert gas atmosphere of argon and an oxygen and water content of less than 1 ppm. After this

To charge the cell, a galvanostatic current was applied, which corresponded to a specific current density based on the active material of the graphite electrode of 15 mA / g. The cell was charged to a final charging voltage of 5.2 V and then discharged to 3 V with the same galvanostatic current, the data in volts being in each case based on the cell voltage between the graphite and the lithium electrode. This charge / discharge process corresponds to one cycle and was repeated 10 times at 20 ± 2 ° C.

FIG. 3 shows the discharge capacity and the efficiency of the charging / discharging process of the electrochemical cell as a function of the number of cycles applied on the x-axis. In this case, the left y-axis shows the value of the discharge capacity, represented as a triangle pointing upwards with the apex, and the right y-axis the efficiency of the

Loading / unloading, represented as a triangle pointing downwards with the tip.

Shown are the first 10 load / unload operations.

It could be determined that the loading / unloading process already in the second

Charging / discharging step was more than 95%, based on a maximum efficiency of 100%, reversible. Furthermore, based on the graphite electrode, a discharge capacity of greater than 100 mAh / g could be achieved.

Use of organic electrolytes can be achieved. Furthermore, a high capacity and energy density could be achieved.

The results show that the use of an ionic liquid as the electrolyte in a dual-ion insertion cell has enabled a very high reversibility and a high capacity of the process. Compared to conventional lithium-ion battery systems, this system offers the advantage of high-temperature operation, as well as Use of various environmentally friendly materials, such as graphites as

Cathode materials.

Example 5

Electrochemical investigation of the long-term stability of the lithium-electrode electrochemical cell at different temperatures

An electrochemical cell having a graphite electrode and a metallic lithium electrode prepared according to Example 3 was examined for long-term stability and behavior at temperatures of 20 ° C, 40 ° C and 60 ° C.

The electrochemical examination was carried out in a cell made of a

modified gas valve from Swagelok ^® under exclusion of oxygen and water. As a galvanostat, a device of the Maccor 4000 series was used. The electrodes used in the measuring cell were round with a diameter of 12 mm, respectively an area of 1.13 cm ² .

Assembly, the cell was equilibrated for 24 hours at the temperature to be tested (20 ± 2 ° C, 40 ± 2 ° C and 60 ± 2 ° C).

To charge the cell, a galvanostatic current was applied, which corresponded to a specific current density based on the active material of the graphite electrode of 50 mA / g. The cell was charged to a final charging voltage of 5.0 V and then discharged to 3.4 V with the same galvanostatic current, the data in volts being in each case based on the cell voltage between the graphite and the lithium electrode. This Charge / Discharge operation is one cycle and has been repeated 500 times at 20 ± 2 ° C, 40 ± 2 ° C and 60 ± 2 ° C.

FIG. 4 shows the discharge capacity and the efficiency of the charging / discharging operation of the electrochemical cell at 20 ° C. as a function of the number of cycles applied on the x-axis. In this case, the left y-axis shows the value of the discharge capacity, represented as a black circle, and the right y-axis the efficiency of the charge / discharge, represented as a tip-down triangle. Shown are the first 500

Loading / unloading operations.

It was found that the charging / discharging process proceeds very reversible, based on a stable discharge capacity of approximately 50 mAh g ^"1 with a capacity retention of more than 99% after 500 charge / discharge cycles. This shows that using an ionic liquid a very high long-term cycle stability of the cell at 20 ° C can be achieved.

FIG. 5 shows the discharge capacities of the charging / discharging process of the electrochemical cell at 20 ° C., 40 ° C. and 60 ° C. as a function of the number of cycles applied on the x-axis. In this case, the left y-axis shows the value of the discharge capacity at 20 ° C, shown as a circle, the value of the discharge capacity at 40 ° C, shown as a triangle and the value of the discharge capacity at 60 ° C, shown as a rectangle. Shown are the first 500 load / unload operations.

It was found that the temperature increase has a positive effect on the discharge capacity, whereby an increase in the discharge capacity of about 50 mAh g ^"1 at 20 ° C to about 105 mAh g ^{" 1} at 60 ° C could be achieved. Furthermore, it was found that the charge / discharge process is very reversible, based on a stable discharge capacity of about 50 mAh g ^"1 at 20 ° C, of about 68 mAh g ^{" 1} at 40 ° C and about 105 mAh g ^"1 at 60 ° C, with a capacity retention of more than 99% after 500 Charging / discharging cycles at 20 and 40 ° C and with a capacity retention of more than 93% after 500 charge / discharge cycles at 60 ° C. This shows that using an ionic liquid a very high long-term cycle stability of the cell in the temperature range of 20 ° C to 60 ° C can be achieved.

Figure 6 shows the voltage curve of the cell in the first charge / discharge cycle at different temperatures (20 ° C, 40 ° C and 60 ° C) against the time plotted on the x-axis time. A difference in the course of the potential curves at different temperatures can be clearly seen. Thus, the intercalation of the anions into the graphite in the first cycle at 40 ° C and 60 ° C takes place even at lower potentials than at 20 ° C. Furthermore, the advantage of the elevated temperatures lies in a lower potential drop during the discharge process, resulting from an increased mobility of the anions.

The results show that the use of an ionic liquid as the electrolyte in a dual-ion insertion cell has enabled a very high reversibility and a high capacity of the process. Compared to conventional lithium-ion battery systems, this system offers the advantage of high-temperature operation, as well as the use of various environmentally friendly materials, such as graphite

Cathode materials.

Example 6

Electrochemical investigation of an electrochemical cell with lithium electrode and carbon cathodes of different particle size The preparation of the electrochemical cell with lithium electrode and carbon cathodes of different particle size was carried out as described in Examples 3 and 1, wherein in the manufacture of the graphite electrodes KS Graphite (TIMCAL®, Bodio, Switzerland) different D90 value of the particle size distribution of 4 μηι, 6 μηι, 10 μηι, 15 μηι, 25 μΐϊΐ υικ1 44 μηι were used.

The electrochemical analysis of the cell was carried out in a cell made of a modified gas valve Swagelok ^® under exclusion of oxygen and water. As a galvanostat, a device of the Maccor 4000 series was used. The electrodes used in the measuring cell were round with a diameter of 12 mm, respectively an area of 1.13 cm ² . The assembly of the cell was carried out in a glove box filled with an inert gas atmosphere of argon and an oxygen and water content of less than 1 ppm. After this

To charge the cell, a galvanostatic current was applied, which corresponded to a specific current density based on the active material of the graphite electrode of 50 mA / g. The cell was charged to a final charging voltage of 5.0 V and then discharged to 3.4 V with the same galvanostatic current, the data in volts being in each case based on the cell voltage between the graphite and the lithium electrode. This charge / discharge process is one cycle and has been repeated 50 times at 20 ± 2 ° C.

FIG. 7 shows the discharge capacities of the electrochemical cell as a function of the D90 value of the particle size distribution of the different KS graphites (TIMCAL®, Bodio, Switzerland) plotted on the x axis. It was found that the discharge capacities were higher, the lower the D90 value of the particle size distribution was, the highest discharge capacity of about 52 mAh g ^{"1 was achieved} at a D90 value of the particle size of 4 μιη. This example illustrates the applicability of the system to different graphites where the discharge capacity depends on the nature of the particles, such as particle size. Based on the investigated KS graphite a maximum discharge capacity of about 52 mAh g ^"1 could be achieved with a particle size of 4 μιη.

Example 7

Preparation and electrochemical investigation of an electrochemical cell with lithium anode and transition metal sulfide cathode

An electrochemical cell was fabricated using a transition metal sulfide based composite electrode and a metallic lithium electrode.

To produce the electrode from metallic lithium, a round electrode with a diameter of 12 mm and a thickness of ΙΟΟμιη from a sheet of metallic lithium (battery grade / battery grade purity, Chemetall) punched out in a glove box and used as a counter electrode.

For the preparation of the transition metal sulfide-based electrode, based on the total weight of the electrode, 85% by weight of TaS ₂ , TiS ₂ , MoS ₂ or WS ₂ (each Sigma Aldrich), 10% by weight of carbon (Super-P Li, TIMCAL®, Bodio, Switzerland) and mixed as a binder 5% by weight of polyvinylidene difluoride (Kynar® Flex 761, Arkema, France) dissolved in N-methyl-2-pyrrolidone (Acros Organics, 99.5%, Extra Dry) as solvent , The mixtures were homogenized in each case with the aid of a T25 digital Ultra-Turrax stirring and a S 25 N-18 G dispersing tool (both IKA, Staufen, Germany) at 5000 rpm for 1 hour. The mixtures were then using a doctor blade on an aluminum foil of a thickness of 20 μιη (purity 99.88%, Evonik Degussa) as

Current arrester applied with a layer thickness of 100 μιη. The electrodes were dried for 12 hours at 80 ° C. Subsequently, each electrodes of a diameter punched out of 12 mm and dried for 24 hours at 120 ° C under vacuum. The surface loading was> 2.5 mg / cm ² . The surface load was determined by weighing the pure aluminum foil and the punched electrodes. The separator used was a glass fiber separator from Whatman (Whatman GF / D, GE Healthcare, Great Britain).

First electrochemical investigations prove the usability of the sulfides as

Cathode material, which itself have a high stability to oxidative decomposition.

Claims

An electrochemical cell comprising a cation reversibly receiving and donating electrode, an anion reversibly receiving and donating electrode and an electrolyte comprising a conducting salt and a solvent, characterized in that the solvent comprises an ionic liquid or a mixture of an ionic liquid and an organic solvent ,

2. An electrochemical cell according to claim 1, characterized in that the cation of the ionic liquid is selected from the group comprising alkylammonium,

Pyridinium, pyrazolium, pyrrolium, pyrrolinium, phosphonium, piperidinium,

Pyrrolidinium, imidazolium and / or sulfonium compounds, preferably selected from the group comprising l-ethyl-3-methylimidazolium, l, 2-dimethyl-3-propylimidazolium, l, 2-diethyl-3,5-dimethylimidazolium, trimethyl-n- hexylammonium, N-alky 1-N-methylpiperidinium, N-alky 1-N-methylmorpholine and / or N-alkyl-N-methylpyrrolidinium, in particular N-butyl-N-methylpyrrolidinium and / or N-methyl-N-propylpyrrolidinium.

3. An electrochemical cell according to claim 1 or 2, characterized in that the anion of the ionic liquid is selected from the group comprising halides,

Cyanides, borates, in particular tetrafluoroborates, perfluoroalkylborates, nitrates, sulphates,

Alkyl sulfates, aryl sulfates, perfluoroalkyl sulfates, sulfonates, alkyl and aryl sulfonates, perfluorinated alkyl sulfonates, aryl sulfonates, phosphates, in particular hexafluorophosphates, perfluoroalkyl phosphates, bis (perfluoroalkylsulfonyl) amides, bis (fluorosulfonyl) imides,

Bis (perfluoroalkylsulfonyl) imides such as bis (trifluoromethylsulfonyl) imide and / or

Fluoroalkylsulfonylacetamides, preferably selected from the group comprising

Bis (trifluoromethanesulfonyl) imide, bis (pentafluoroethanesulfonyl) imide, bis (fluorosulfonyl) imide, 2,2,2-trifluoro-N- (trifluoromethanesulfonyl) acetamide, tetrafluoroborate, Pentafluoroethane trifluoroborate, hexafluorophosphate, bisoxolato borate, difluoro (oxalato) borate and / or tri (pentafluoroethane) trifluorophosphate.

4. Electrochemical cell according to one of the preceding claims, characterized

in that the organic solvent is selected from the group comprising aliphatic hydrocarbons, in particular pentane, aromatic hydrocarbons, in particular toluene, alkenes, in particular hexene, alkynes, in particular heptin, halogenated hydrocarbons, in particular chloroform or fluoromethane, alcohols, in particular ethanol, glycols, in particular ethylene glycol and diethylene glycol, ethers, in particular diethyl ether and tetrahydrofuran, esters, in particular ethyl acetate, carbonates, in particular diethyl carbonate, lactones, in particular gamma-butyrolactone and gamma-valerolactone, acetates, in particular sodium acetate, sulphones, in particular sulpholane, sulphoxides, in particular dimethyl sulphoxide, amides, in particular acetic acid (trimethylsilyl) amide, nitriles, in particular acetonitrile, amines, in particular dimethylamine, ketones in particular acetone, aldehydes, in particular hexanal, sulfides, in particular carbon disulfide, carbonic esters, in particular dimethyl carbonate and ethylene carbonate, Carboxylic acids in particular

Formic acid, and / or urea derivatives, in particular dimethylpropyleneurea

5. Electrochemical cell according to one of the preceding claims, characterized

in that the organic solvent is selected from the group comprising ethylene carbonate, fluoroethylene carbonate, propylene carbonate, diethyl carbonate,

Dimethyl carbonate, ethyl methyl carbonate, acetonitrile, glutaronitrile, adiponitrile, pimelonitrile, fluoroethylene carbonate, gamma-butyrolactone, gamma-valerolactone, dimethoxyethane, dimethyl sulfoxide, vinylene carbonate, vinylene ethylene carbonate, 1,3-dioxalane, methyl acetate and / or mixtures thereof.

6. Electrochemical cell according to one of the preceding claims, that the anions reversible receiving and donating electrode material is selected from the group comprising

Carbon, graphite, graphene, or carbon nanotubes,

Carbon oxides of the formula (CO _y ) _m , which are solid at room temperature and where y is in the range of 0.01 to 1 and m is in the range of 1 to 100,

Range is from 1 to 10 and z ranges from 1 to 3,

Selenide M _z Se _y of transition metals M selected from the group comprising Ti,

V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn and / or Al wherein y in the

Range is from 1 to 10 and z ranges from 1 to 3,

Telluride M _z Te _y of transition metals M selected from the group comprising Ti,

Range is from 1 to 10 and z ranges from 1 to 3,

complex halides of metals selected from the group comprising Na, Mg,

Al, Si, P, S, K, Ca, Ti, Zn, Cu, Ni, Co, Fe, Mn, Cr, V, Zr, Nb, Mo and / or Sn, - anion-introducing metal oxides of the transition metals, preferably selected from the group comprising W, Mo, Cr, V and / or Ti,

Metal silicates of the formula Me _n [(Si _x O _y ) ^{4x "2y} ] where Me is selected from the group consisting of Fe, Li, Ni, Ti, Na, K, Ba, Ca, Mg, Mn, Co, Al, Sn, Ag, Au, Cu and / or Sb, and 1 <x <65, 1 <y <130 and 1 <n <12, where Si can be replaced by Al up to a ratio of 1: 1,

Metal aluminates of the formula (MeAl (OH) _x ) where Me is selected from the group consisting of Fe, Li, Ni, Ti, Na, K, Ba, Ca, Mg, Mn, Co, Al, Sn, Ag, Au, Cu and / or Sb and 2 <x <7, and / or Metal hydroxides corresponding to substantially the general formula: M _m D _d T (OH) (3 + _m + d), wherein

M is a metal cation selected from the group of alkaline earth and alkali metals, and m is in the range of 0 to 8,

D is at least one bivalent metal cation from the group comprising Mg, Ca,

Mn, Fe, Co, Ni, Cu and / or Zn, and d is in the range of 0 to 8,

(3 + m + d) corresponds to the number of OH groups which are essentially the

Satisfies valency requirements of M, D and T, where m + d is not equal to zero.

7. An electrochemical cell according to one of the preceding claims, characterized

characterized in that the cation, in particular lithium cations, reversibly receiving and donating electrode material is selected from the group comprising

Carbon, in particular amorphous or semi-crystalline carbon particles, graphites,

Graphene,

Metals and metal alloys of metals selected from the group consisting of Li, Ni, Ti, Na, K, Ba, Ca, Mg, Ga, Ge, In, V, Si, Al, Sn, Ag, Au, Cu and / or Sb .

- Phosphide of the formula M _k P _x with P _x ^{k ~} or P _x ^{(x + 2) "} , where 1 <x <8 and 1 <k <7, where M is selected from the group of alkali, alkaline earth and Transition metals, metal oxides of the transition metals, preferably selected from the group comprising W, Mo, Cr, V and / or Ti,

Sulfides M _z S _y of transition metals M selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn, W and / or Al where y is in the range of 1 to 10 and z is in the range of 1 to 3, Metal fluorides with one or more metals selected from the group consisting of Fe, Cr, Nb, Rh, Ag, Au, Se, Co, Te, Ni, Cu, V, Mo, Pb, Sb, Bi and / or Si, and alkaline earth metal titanates having the formula A _x Ti _y 0 ₄ or ΕΑο _ι5χ Ti _y 0 ₄ , wherein 0.8 <x <1.4 and 1.6 <y <2.2, and / or

- Alkali and alkaline earth metal cuprates of the formulas A _x Cu _y 0 ₂ or EA _x / ₂ Cu _y 0 ₂ , where

0.8 <x <1.2 and 0.7 <y <1.25.

8. An electrochemical cell according to one of the preceding claims, characterized

in that the cation, in particular lithium cation, reversibly accepting and donating electrode material is usable at a potential in the range from 0.7 V to 2.2 V with respect to lithium, preferably selected from the group comprising TiO ₂ , WO ₂ , MoO ₂ and / or Li ₄ Ti ₅ 0i ₂ .

9. An electrochemical cell according to one of the preceding claims, characterized

in that the conductive salt is selected from the group comprising ZF, ZCl, ZBr, ZI, ZPF ₆ , ZAsF ₆ , ZC 10 ₄ , ZNO ₃ , Z ₂ SO ₄ , ZSbF ₆ , ZPtClg, ZCN, Z (CF ₃ ) SO ₃ , ZC (S0 ₂ CF ₃₎ _3, ZPF ₃ (CF ₃₎ _3, ZPF ₄ (C ₂ 0 _4), ZBF _4, for example (C ₂ 0 ₄₎ _2, ZBF ₂ (C ₂ 0 _4), ZB ( C ₂ O ₄ ) (C ₃ O ₄ ), Z (C ₂ F ₅ BF ₃ ), Z ₂ Bi ₂ Fi ₂ , ZN (SO ₂ F) ₂ , ZN (SO ₂ CF ₃ ) ₂ and / or ZN ( S0 ₂ C ₂ F ₅ ) ₂ , wherein Z is selected from the group comprising Li, Na, K and / or H.

10. Use of an ionic liquid as solvent in an electrochemical cell comprising a cation reversibly receiving and donating electrode, an anion reversibly receiving and donating electrode and an electrolyte comprising a conducting salt and a solvent.