DE102011054119A1 - Electrochemical cell - Google Patents

Abstract

The invention relates to 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, wherein the solvent comprises an ionic liquid or a mixture of an ionic liquid and an organic solvent.

Description

The invention relates to an electrochemical cell, in particular a secondary electrochemical cell, which is 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, metal oxides of mixtures of nickel and cobalt are frequently used in lithium-ion batteries as the electrode material, the production costs being greatly increased by the use of nickel and, in particular, cobalt. 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 an incorporation of lithium into 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 reduce the conductivity and thus the capacity of the cells at low temperatures. Due to the dual incorporation 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 achieve only low charge and discharge efficiency throughout the lifetime.

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 having improved temperature resistance.

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 conductive 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 discharging could be realized than with the use of 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 allows the electrochemical cell to provide increased safety, in particular with regard to the flammability of the cell and a decomposition of the electrolyte at high temperatures. Thus, the electrochemical cell according to the invention has a higher reliability. It is of particular advantage that the electrochemical cell can be operated in the low-temperature range, but in particular also in the high-temperature range. 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 in particular organic anions.

For the purposes of this invention, the term "ionic liquid" means salts which form a class of liquids which contain exclusively ions and are liquid at temperatures below 180 ° C.

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 have lower toxicity and hazard potential compared to organic solvents. 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 O) N ^- (OX ² F) in which X ¹ and X ^{2 are} identical or different and comprise SO or PF.

eine Verbindung der folgenden Formel

eine Verbindung der folgenden Formel

oder eine Verbindungen der folgenden Formeln

in denen:
W O, S oder N ist, und in denen N wahlweise durch R¹ substituiert ist, wenn es die Wertigkeit zulässt; R¹, R³, R⁴ sind gleich oder verschieden voneinander und sind -H; -Alkyl-, Alkenyl-, Oxaalkyl, Oxaalkenyl, Azaalkenyl, Thioalkyl, Thioalkenyl, Dialkylazoradikale, wobei die Radikale linear, verzweigt oder cyclisch sein können und 1 bis 18 Kohlenstoffatome umfassen; -cyclische oder heterocyclische aliphatische Radikale mit 4 bis 26 Kohlenstoffatomen, die wahlweise wenigstens eine Seitenkette umfassen, die ein oder mehrere Heteroatome umfasst; -Gruppen, die mehrere aromatische oder heterocyclische Kerne umfassen, die kondensiert oder nicht kondensiert sind und die wahlweise ein oder mehrere Stickstoff-, Sauerstoff, Schwefel oder Phosphoratome enthalten, wobei zwei Gruppen R¹, R³ oder R⁴ einen Ring oder einen Heterocyclus mit 4 bis 9 Atomen bilden können und ein oder mehrere Gruppen R¹, R³ oder R⁴ auf demselben Kation Teil einer Polymerkette sein können; -R² und R⁵ bis R⁹ sind gleich oder verschieden voneinander und stellen R¹, R¹O-(R¹)₂N-, R¹S- dar, wobei R¹ wie vorstehend definiert ist.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

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 from 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; Groups comprising a plurality of aromatic or heterocyclic nuclei which condenses or not are condensed and which optionally contain one or more nitrogen, oxygen, sulfur or phosphorus atoms, wherein two groups R ¹ , R ³ or R ^{4 may 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 can 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 is} O- (R ¹ ) ₂ N-, R ¹ S-, wherein R ^{1 is} as defined above.

die Imidazolium-, Triazolium-, Thiazolium und Oxazoliumderivate umfassen;
Verbindungen der Formel

die Triazolium-, Oxadiazolium und Thiadiazoliumderivate umfassen;
Verbindungen der Formel

vorzugsweise Pyridiniumderivate

oder Verbindungen der Formeln

in denen:
W O, S oder N ist und in denen N wahlweise durch R¹ substituiert ist, wenn es die Wertigkeit erlaubt; R¹, R³, R⁴ gleich oder verschieden voneinander sind und -H; -Alkyl-, Alkenyl-, Oxaalkyl, Oxaalkenyl, Azaalkyl-, Azaalkenyl, Thioalkyl, Thioalkenyl, Dialkylazoradikale, wobei die Radikale linear, verzweigt oder cyclisch sein können und 1 bis 18 Kohlenstoffatome umfassen; -cyclische oder heterocyclische aliphatische Radikale mit 4 bis 26 Kohlenstoffatomen, die wahlweise wenigstens eine Seitenkette umfassen, die ein oder mehrere Heteroatome wie Stickstoff, Sauerstoff oder Schwefel umfasst; -Aryle, Arylalkyle, Alkylaryle und Alkenylaryle mit 5 bis 26 Kohlenstoffatomen, die wahlweise ein oder mehrere Heteroatome in dem aromatischen Kern umfassen; -Gruppen, die mehrere aromatische oder heterocyclische Kerne umfassen, die kondensiert oder nicht kondensiert sind und die wahlweise ein oder mehrere Stickstoff-, Sauerstoff-, Schwefel- oder Phosphoratome enthalten, wobei zwei Gruppen R¹, R³ oder R⁴ einen Ring oder einen Heterocyclus mit 4 bis 9 Atomen bilden können, und ein oder mehrere Gruppen R¹, R³ oder R⁴ auf demselben Kation Teil einer Polymerkette sein können; und -R² und R⁵ bis R⁹ gleich oder verschieden voneinander sind und R¹, R¹O-(R¹)₂N-, R¹S- darstellen, wobei R¹ wie vorstehend definiert ist.Preferred cations include compounds of the formula:

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

the triazolium, oxadiazolium and thiadiazolium derivatives include;
Compounds of the formula

preferably pyridinium derivatives

or compounds of the formulas

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, wherein the radicals may be linear, branched or cyclic and comprise from 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; -Aryle, arylalkyl, alkylaryl and alkenylaryl 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 which optionally contain one or more nitrogen, oxygen, sulfur or phosphorus atoms, wherein two R ¹ , R ³ or R ^{4 groups form} a ring or a group Can form a heterocycle of 4 to 9 atoms, and one or more groups R ¹ , R ³ or R ⁴ on the same cation can be part of a polymer chain; and -R ² and R ⁵ to R ^{9 are the} same or different from each other and R ¹ , R ^{1 is} O- (R ¹ ) ₂ N-, R ¹ S-, wherein R ^{1 is} as defined above.

The groups R ¹ , R ³ and R ⁴ may carry groups which are active in the polymerization, such as double bonds or epoxides, or reactive functions 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 copolymerized with other epoxides.

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 ^- ; I ^- ; NO ₃ ^- ; (MR ¹⁰ ) ₄ ^- A (R ¹⁰ ) ₆ ^- ; R ¹¹ O ₂ ^- ; [R ¹¹ ONZ ¹ ] ^- ; [R ¹¹ YOCZ ² Z ³ ] ^- ; 4,5-dicyano-1,2,3-triazole, 3,5-bis (R _F ) -1,2,4-triazole, tricyanomethane, pentacyanocyclopentadiene, pentakis (trifluoromethyl) cyclopentadiene, derivatives of barbituric acid and meldrumic acid and their derivatives 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 an or a plurality of oxa, thio or aza substituents are substituted, 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 ¹¹ , P (C (CN) ₂ R ¹¹ , 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 each other R ¹¹ , R ^{11 is} YO or CN, which group may optionally be part of a polymer chain.

The ionic liquids can advantageously be easily prepared by ion exchange in water. Furthermore, these salts advantageously have a good stability to oxidation. Another advantage of the ionic compounds is the lower cost of the starting anions. The low Volatility of the ionic liquids, thermal and electrochemical stability, and increased conductivity are particularly advantageous for use as solvents in electrochemical cells operating at lower, and especially higher, temperatures. 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 compounds.

Preferably, the cation of the ionic liquid is selected from the group comprising 1-ethyl-3-methylimidazolium (EMI ⁺ ), 1,2-dimethyl-3-propylimidazolium (DMPI ⁺ ), 1,2-diethyl-3,5-dimethylimidazolium ( DEDMI ⁺ ), trimethyl-n-hexylammonium (TMHA ⁺ ), N-alkyl-N-methylpiperidinium (PIP _{R`R</sub> <sup>+</sup> ), N-alkyl-N-methylmorpholinium (MORP <sub>R`R} ⁺ ) and / or N-alkyl N-methylpyrrolidinium (PYR _{R`R</sub> <sup>+</sup> ). The cation of the ionic liquid is preferably 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 <sub>R`R} ⁺ ), 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 consisting of halides, cyanides, borates, in particular tetrafluoroborates, perfluoroalkylborates, nitrates, sulfates, alkylsulfates, arylsulfates, perfluoroalkylsulfates, sulfonates, alkyl and arylsulfonates, perfluorinated alkylsulfonates, arylsulfonates, phosphates, in particular hexafluorophosphates, Perfluoralyklphosphate, bis (perfluoroalkylsulfonyl) amides, bis (fluorosulfonyl) imides, bis (perfluoroalkylsulfonyl) imides such as bis (trifluoromethylylsulfonyl) imide and / or Fluoroalkylsulfonylacetamide.

Preferably the anion of the ionic liquid is selected from the group consisting of bis (trifluoromethanesulfonyl) imide (TFSI ^-), bis (pentafluorethansulfonyl) imide (BETI ^-), bis (fluorosulfonyl) imide (FSI ^-), 2,2,2-trifluoro- N- (trifluoromethanesulfonyl) acetamide (TSAC ^-), tetrafluoroborate (BF ₄ ^-), Pentafluorethanetrifluoroborat (C ₂ F ₅ BF ₃ ^-), hexafluorophosphate (PF ₆ ^-), Bisoxolatoborat (BOB ^-), difluoro (oxalato) borate (DFOB ^- ) and / or tri (pentafluoroethane) trifluorophosphate ((C ₂ F ₅ ) ₃ PF ₃ ^- ). More preferably, the anion of the ionic liquid is selected from the group consisting of bis (trifluoromethanesulfonyl) imide (TFSI ^-), bis (fluorosulfonyl) imide (FSI ^-) Bisoxolatoborat (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.

In preferred embodiments, the solvent is an ionic liquid comprising a cation selected from the group comprising pyrrolidinium and / or pyrrolidinium compounds, preferably an N-alkyl-N-alkylpyrrolidinium (PYR _R`R ⁺ ), in particular N-butyl-N-methylpyrrolidinium ( PYR ₁₄ ⁺ ) and / or N-methyl-N-propylpyrrolidinium (PYR ₁₃ ⁺ ) and an anion selected from the group comprising bis (trifluoromethanesulfonyl) imide (TFSI ^- ), bis (pentafluoroethanesulfonyl) imide (BETI ^- ), bis (fluorosulfonyl ) imide (FSI ^- ), 2,2,2-trifluoro-N- (trifluoromethanesulfonyl) acetamide (TSAC ^- ), tetrafluoroborate (BF ₄ ^- ), pentafluoroethane trifluoroborate (C ₂ F ₅ BF ₃ ^- ), hexafluorophosphate (PF ₆ ^- ) , Bisoxalatoborate (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 (TFSI ^- ), bis (fluorosulfonyl) imide (FSI ^- ), bisoxalatoborate (BOB ^- ) and d / 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 ionic liquids or their mixtures with other metallic salts are 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 homo- or copolymers of polyethylene oxide (PEO), polypropylene oxide (PPO), polyvinylidene fluoride (PVdF), polyvinylidene fluoride hexafluoropropylene (PVdF-HFP), polyacrylonitrile (PAN), polymethylmethacrylate (PMMA), polyethylmethacrylate (PEMA), polyvinylacetate (PVAc), polyvinylchloride (PVC), polyphosphazenes, polysiloxanes, polyvinylalcohol (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 ₁₃ FSI) 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 have 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, 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 acid esters, in particular dimethyl carbonate and ethyl encarbonate, carboxylic acids, in particular formic acid, and / or urea derivatives, in particular dimethylpropyleneurea.

The organic solvents can advantageously support 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, ethylmethyl carbonate, acetonitrile, glutaronitrile, adiponitrile, pimelonitrile, fluoroethylene carbonate, gamma-butyrolactone, gamma-valerolactone, dimethoxyethane, dimethylsulfoxide, vinylene carbonate, vinyleneethylene 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 1,3-dioxolan-2-one according to the IUPAC 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 provide a very high conductivity of the electrolyte solution.

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 according to the invention, the positive electrode preferably comprises an intercalation compound into which the anion can be incorporated. In particular, are carbon or Metal compounds in particular 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 and / or Al, where 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, where y is in the range of 1 to 10 and z is in the range of 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 is in the range of 1 to 10 and z is in the range of 1 to 3,
• 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,
• Anion-imparting 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
• - layered, mixed metal hydroxides corresponding essentially to the general formula: M _m D _d T (OH) _{(3 + m + d)} , where M is a metal cation selected from the group of alkaline earth 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 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, 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 that substantially satisfy the 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" is to be understood as meaning carbonaceous or rich materials such as graphite, pitch or tar, pitch coal, coke, synthetic graphite, carbon black, 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, in the technical processing occurring carbons such as carbon black, activated carbon, amorphous carbon, carbon fibers, graphites, graphenes, graphite oxides, as well as carbon nanotubes, carbon nanofoam, amorphous carbon or mixtures thereof can be used.

Carbon particles may be amorphous, crystalline or partially crystalline. In particular, amorphous or partially crystalline carbon so-called soft or hard carbons are preferably used. 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. Heat treatment of carbonaceous materials increases their crystallinity and may increase the ability to incorporate 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 an average diameter in the range of ≥ 2 nm to ≦ 50 μm, preferably in the range of ≥ 10 nm to ≦ 30 μm, particularly preferably in the range of ≥ 30 nm to ≦ 30 μm.

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.

The electrodes are usually composite electrodes, which may contain binders and additives in addition to the materials reversibly receiving and donating or intercalating and deintercalating the respective ions. 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 are, 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, for example copper particles, in particular metal particles with a size in the nanometer range, and 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 wt .-% to ≤ 97 wt .-%, based on the total weight of the electrode. The proportion of ≥70% by weight of the electrode formed in a dual interstitial cell of the anion intercalation compound formed of carbon and / or graphite 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 formulas M _z S _y , M _z Se _y and 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 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. Also useful are selenides such as 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 complex 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 F ₁₄ ), usovite (Ba ₂ CaMgAl ₂ F ₁₄ ) 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 , TiO ₂ and / or WO ₂ .

Also useful compounds are in particular layered 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, 1 ≤ n ≤ 12 and 1 ≤x ≤ 65 and 1 ≤ y ≤ 130. In the metal silicates of the formula Me _n [(Si _x O _y ) ^4x-2y ], Si may be replaced by Al up to a ratio of 1: 1. 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 comprising Li ₂ FeSiO ₄ , Li ₂ CoSiO ₄ , Li ₂ MnSiO ₄ and / or NaFeSiO 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 D _d T (OH) _{(3 + m + d)} , where 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 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 one Metal cation selected from the group comprising Al, Ga, Fe and / or Cr, and (3 + m + d) corresponds to the number of OH groups that substantially satisfies the valence requirements of M, D and T, where m + d does not is equal to zero.

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

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, in particular lithium.

In the case of the cells according to the invention, the negative electrode is preferably an intercalation compound into which the cation can be incorporated. In particular, carbon compounds, metals and metal alloys, or metal compounds, in particular alkali, alkaline earth or transition metal compounds such as alkali metal and Erdalkalimetalli-titanates are.

• – Kohlenstoff insbesondere amorphe oder teilkristalline Kohlenstoffpartikel, Graphite, Graphene,
• – fluorierte Kohlenstoffe der Formel (CF_x)_n wobei x im Bereich von 0,01 bis 1,24 liegt und n im Bereich von 1 bis 1000 liegt,
• – Metalle und Metalllegierungen von Metallen ausgewählt aus der Gruppe umfassend Li, Ni, Ti, Na, K, Ba, Ca, Mg, Ga, Ge, In, V, Si, Al, Sn, Ag, Au, Cu und/oder Sb,
• – Phosphide der Formel M_kP_x mit P_x ^k- oder P_x ^(x+2)-, wobei 1 ≤ x ≤ 8 und 1 ≤ k ≤ 7, wobei M ausgewählt ist aus der Gruppe der Alkali-, Erdalkali- und Übergangsmetalle,
• – Metall-Oxide der Übergangsmetalle, bevorzugt ausgewählt aus der Gruppe umfassend W, Mo, Cr, V und/oder Ti,
• – Sulfide M_zS_y von Übergangsmetallen M ausgewählt aus der Gruppe umfassend Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn und/oder Al wobei y im Bereich von 1 bis 10 liegt und z im Bereich von 1 bis 3 liegt,
• – Metallfluoride mit einem oder mehreren Metallen ausgewählt aus der Gruppe umfassend Fe, Cr, Nb, Rh, Ag, Au, Se, Co, Te, Ni, Cu, V, Mo, Pb, Sb, Bi und/oder Si,
• – Alkali- und Erdalkalimetall-Titanate mit der Formel A_xTi_yO₄ oder EA_0,5x Ti_yO₄, wobei 0,8 ≤ x ≤ 1,4 und 1,6 ≤ y ≤ 2,2 ist, und/oder
• – Alkali- und Erdalkalimetall-Cuprate der Formeln A_xCu_yO₂ oder EA_x/2Cu_yO₂, wobei 0,8 ≤ x ≤ 1,2 und 0,7 ≤ y ≤ 1,25.

In preferred embodiments, the cation is, preferably lithium and sodium, in particular lithium, 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 .
• - Phosphide of the formula M _k P _x with P _x ^k or P _x ^{(x + 2) -} , wherein 1 ≤ x ≤ 8 and 1 ≤ k ≤ 7, wherein 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 and / or Al wherein y im 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 metal and alkaline earth metal titanates having the formula A _x Ti _y O ₄ or EA _{0.5 x} Ti _y O ₄ , where 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 O ₂ or EA _{x / 2} Cu _y O 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, in the technical processing occurring carbons such as carbon black, activated carbon, amorphous carbon, carbon fibers, graphites, graphenes, graphite oxides, as well as carbon nanotubes, carbon nanofoam, amorphous carbon or mixtures thereof can be used.

Carbon particles may be amorphous, crystalline or partially crystalline. In particular, amorphous or partially crystalline carbon so-called soft or hard carbons are preferably used. 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. Heat treatment of carbonaceous materials increases their crystallinity and may increase the ability to incorporate 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 an average diameter in the range of ≥ 2 nm to ≦ 50 μm, preferably in the range of ≥ 10 nm to ≦ 30 μm, particularly preferably in the range of ≥ 30 nm to ≦ 30 μm.

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 cation, in particular lithium, reversible receiving and donating electrode material is carbon-based. Preferably, the cations 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 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 well suited cations such as lithium or potassium and outsource. In particular, lithium metal or lithium metal alloys are well suited in combination 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. Particular preference is given to using metal oxides selected from the group comprising MoO, MoO ₂ , TiO ₂ and / or WO 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 and / or Al 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 complexing ligands. In particular, the complex fluoids are insoluble in the electrolyte and are solid at room temperature (20 ± 2 ° C). Preference is given to 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, in particular lithium, reversibly absorbing and donating electrode materials are alkali metal (A) and alkaline earth metal (EA) titanates of the formula A _x Ti _y O ₄ or EA _0.5x Ti _y O 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 Ti ₅ O ₁₂ 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, in particular lithium, reversibly receiving and donating electrode materials are alkali (A) and alkaline earth metal (EA) cuprates of the formulas A _x Cu _y O ₂ or EA _{x / 2} Cu _y O ₂ , where 0 , 8 ≤ x ≤ 1.2 and 0.7 ≤ y ≤ 1.25.

In preferred embodiments, the cation, particularly lithium, 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, reversibly receiving and donating electrode material is selected from the group comprising TiO ₂ , WO ₂ , MoO ₂ and / or Li ₄ Ti ₅ O ₁₂ . 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 TiO ₂ , WO ₂ , MoO ₂ and / or Li ₄ Ti ₅ O ₁₂ 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 wt .-% to ≤ 95 wt .-%, 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 O ₁₂ 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, the environmental friendliness of the cell is advantageously higher and the cost of the cathode material is lower than in classical systems.

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 the 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 (ClO ₄ ) ₂ , Y (NO 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 (SO ₂ CF ₃ ) ₃ ) ₂ , Y (PF ₃ (CF ₃ ) ₃ ) ₂ (YFAP ₂ ), Y / PF ₄ (C ₂ O 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 (SO ₂ F) ₂ ) ₂ (YFSI ₂ ), Y (N (SO ₂ CF ₃ ) ₂ ) ₂ (YTFSI ₂ ) and / or Y (N (SO ₂ C ₂ F ₅ ) ₂ ) ₂ (YBETI ₂ ), wherein Y is selected from the group comprising 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 (ClO ₄ ) ₃ , X (SbF ₆ ) ₃ , X (NO ₃ ) ₃ , X ₂ (SO ₄ ) ₃ , X (PtCl ₆ ) ₃ , X (CN) ₃ , X ((CF ₃ ) SO ₃ ) ₃ (XTf ₃ ), X (C ( SO 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 (SO ₂ F) ₂ ) ₃ (XFSI ₃ ), X (N ( SO ₂ CF ₃ ) ₂ ) ₃ (XTFSI ₃ ) and / or X (N (SO ₂ C ₂ F ₅ ) ₂ ) ₃ (XBETI ₃ ), where X is selected from the group comprising Al and / or B.

In preferred embodiments, the conducting salt is selected from the group comprising ZF, ZCl, ZBr, ZI, ZPF ₆ , ZAsF ₆ , ZClO ₄ , ZNO ₃ , Z ₂ SO ₄ , ZSbF ₆ , ZPtCl ₆ , 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), where 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 (SO 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 , LiClO ₄ , LiSbF ₆ , LiPtCl ₆ , 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 B ₁₂ F ₁₂ (LiDFB), LiN (SO ₂ F) ₂ (LiFSI), LiN (SO ₂ CF ₃ ) ₂ (LiTFSI) and / or LiN (SO ₂ C ₂ F ₅ ) ₂ (LiBETI), preferably LiPF ₆ .

In particular, LiN (SO ₂ F) ₂ (LiFSI), LiN (SO ₂ CF ₃ ) ₂ (LiTFSI), and LiB (C ₂ O ₄ ) ₂ (LiBOB) can lead to a good capacity of the 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, above the potential of lithium. This is particularly advantageous because dual storage cells are operated at high cell voltages.

Preferably, the anion is selected from the group comprising F ^- , Cl ^- , Br ^- , I ^- , PF ₆ ^- , BF ₄ ^- , B (C ₂ O ₄ ) ₂ ^- (BOB), BF ₂ (C ₂ O ₄ ) ^- (DFOB), B (C ₂ O ₄ ) (C ₃ O ₄ ) ^- (MOB), (C ₂ F ₅ BF ₃ ) ^- (FAB), (CF ₃ ) SO ₃ ^- , B ₁₂ F ₁₂ ^2- (DFB), N (SO ₂ F) ₂ ^- (FSI), N (SO ₂ CF ₃ ) ₂ ^- (TFSI) and / or N (SO ₂ C ₂ F ₅ ) ₂ ^- (LiBETI). The anion is preferably selected from the group consisting of PF ₆ ^- , N (SO ₂ F) ₂ ^- (FSI), N (SO ₂ CF ₃ ) ₂ ^- (TFSI) and / or B (C ₂ O 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 (SO ₂ F) ₂ , N (SO ₂ CF ₃ ) ₂ and B (C ₂ O ₄ ) ₂ can also be incorporated into the electrode in the dual storage system according to the invention. 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 to 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 O ₄ ) ₂ ^- (BOB), BF ₂ (C ₂ O ₄ ) ^- (DFOB), B (C ₂ O ₄ ) (C ₃ O ₄ ) ^- (MOB), (C ₂ F ₅ BF ₃ ) ^- (FAB), (CF ₃ ) SO ₃ ^- , B ₁₂ F ₁₂ ^2- (DFB), N (SO ₂ F) ₂ ^- (FSI), N (SO ₂ CF ₃ ) ₂ ^- (TFSI) and / or N (SO 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.

Preferably, the particular secondary electrochemical cell comprises a conducting salt selected from the group consisting of LiN (SO ₂ F) ₂ (LiFSI), LiN (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 _R`R ⁺ ), in particular N-butyl-N-methylpyrrolidinium (PYR ₁₄ ⁺ ) and / or N-methyl-N-propylpyrrolidinium (PYR ₁₃ ⁺ ) and an anion selected from the group comprising bis (trifluoromethanesulfonyl) imide (TFSI ^- ), bis (fluorosulfonyl) imide (FSI ^- ), bisoxolatoborate (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 additives are, for example, metal oxides such as TiO ₂ , Al ₂ O ₃ and SiO ₂ , preferably SiO ₂ . Further 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 nonwovens. 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 an electrolyte 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 the use of an ionic liquid as a solvent in a based on the dual-ion insertion principle lithium-based energy storage. Lithium-based energy stores are preferably selected from the group comprising lithium batteries, lithium-ion batteries, lithium-ion secondary batteries, 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:

1 Figure 3 shows the discharge capacity and efficiency of one embodiment of an electrochemical cell versus the number of charge / discharge cycles.

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

3 Discharge capacity and efficiency of another embodiment of an electrochemical cell against the number of charge / discharge cycles.

example 1

Production of an electrochemical cell

An electrochemical cell with two composite electrodes was produced. Were used to prepare the graphite electrode based on the total weight of the electrode, 90 wt .-% of graphite (graphite KS6, TIMCAL ^®, Bodio, Switzerland), 5 wt .-% carbon (Super-P Li, TIMCAL ^®, Bodio, Switzerland) and as a binder 5 wt .-% sodium carboxymethylcellulose (Walocel® ^® CRT 2000 PPA 12, Dow Wolff Cellulosics, The Dow Chemical Company, Midland, MI, USA) as the solvent in deionized water. The mixture was homogenized using a T25 digital Ultra-Turrax stirrer and a S 25 N-18 G dispersing tool (both IKA, Staufen, Germany) at 5000 rpm for 1 hour. The mixture was then (in 99.88%, Evonik-Degussa ^®) using a doctor blade onto an aluminum foil having a thickness of 20 .mu.m is applied as a current conductor with a layer thickness of 200 microns. 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 surface load was determined 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 Ti ₅ O ₁₂ (battery grade / battery grade purity, Südchemie, Munich, Germany), 10% by weight of carbon (superoxide) P Li, TIMCAL ^®, Bodio, Switzerland) and as a binder, 5 wt .-% polyvinylidene fluoride (Kynar Flex ^® 761, Arkema, France) dissolved in N-methyl-2-pyrrolidone (Acros Organics, 99.5%, extra Dry) mixed as a solvent. 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 to an aluminum foil having a thickness of 20 μm (purity 99.88%, Evonik-Degussa) as a current conductor with a layer thickness of 175 μm. 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 (Pyr ₁₄ 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) were dissolved in the ionic liquid.

Example 2

Electrochemical investigation of the electrochemical cell

Electrochemical investigation of the electrochemical cell prepared according to Example 1 was carried out in a cell made of a modified gas valve Swagelok ^® under 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 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 corresponds to one cycle and was 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 TFSI ^- because they are in the two electrodes as charge carriers. When discharging these ions are released back to the electrolyte and thus increases the ion concentration again.

The 1 shows the discharge capacity and the efficiency of the charging / discharging of the electrochemical cell in dependence on the number of cycles applied on the x-axis. In this case, the left y-axis shows the value of the discharge capacity, shown 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 after the first cycle to more than 99%, based on a maximum efficiency of 100%, was reversible and remained constant over the course of more than 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 can be achieved using organic electrolytes.

The 2 shows the current / voltage curve of the cell against the time plotted on the x-axis. The voltage of the cell is shown in solid 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. In 2 The first 10 loading / unloading processes are shown.

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. To produce the metallic lithium electrode, a round electrode of 12 mm diameter and 100 μm thick was punched out of a sheet of metallic lithium (battery grade / battery grade purity, Chemetall) punched out in a glovebox and used as a counter electrode.

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 (Pyr ₁₄ 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) were dissolved in the ionic liquid.

Example 4

Electrochemical investigation of the electrochemical cell with lithium electrode

Electrochemical investigation of the electrochemical cell prepared according to Example 3 was carried out in a cell made of a modified gas valve Swagelok ^® under 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 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 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.

The 3 shows the discharge capacity and the efficiency of the charging / discharging of the electrochemical cell in dependence on 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, and the right y-axis shows the efficiency of the charge / discharge process, shown as a tip-down triangle. Shown are the first 10 load / unload operations.

It was found that the charge / discharge process was already more than 95% reversible in the second charge / discharge step, based on a maximum efficiency of 100%. Furthermore, based on the graphite electrode, a discharge capacity of greater than 100 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 can be achieved using organic electrolytes. 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 the use of more environmentally friendly materials such as graphites as cathode materials.

Claims (10)

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. 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 1-ethyl-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium, 1,2-diethyl-3,5-dimethylimidazolium, trimethyl-n-hexylammonium, N-alkyl-N- methylpiperidinium, N-alkyl-N-methylmorpholinium and / or N-alkyl-N-methylpyrrolidinium, in particular N-butyl-N-methylpyrrolidinium and / or N-methyl-N-propylpyrrolidinium. 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, perfluoroalkyl borates, nitrates, sulfates, alkyl sulfates, aryl sulfates, perfluoroalkyl sulfates, sulfonates, alkyl and aryl sulfonates, perfluorinated alkylsulphonates, arylsulphonates, phosphates, in particular hexafluorophosphates, perfluoroalkyaliphosphates, 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. 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, K. oleic acid esters, in particular dimethyl carbonate and ethylene carbonate, carboxylic acids, in particular formic acid, and / or urea derivatives, in particular dimethylpropyleneurea. 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, ethylmethyl 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. 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, - fluorinated carbons of the formula (CF _x ) _n where x in the range of 0.01 to 1.24 and n ranges from 1 to 1000, - carbon oxides of the formula (CO _y ) _m which are solid at room temperature and where y ranges from 0.01 to 1 and m ranges from 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 and / or Al 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 is in the range of 1 to 10 and z is in the range of 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 is in the range of 1 to 10 and z is in the range of 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-inserting 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 ) 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 - metal hydroxides corresponding essentially to 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, 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 that substantially satisfy the valency requirements of M, D, and T, where m + d is not equal to zero. Electrochemical cell according to one of the preceding claims, characterized in that the cations, in particular lithium, reversibly receiving and donating electrode material is selected from the group comprising - carbon in particular amorphous or partially crystalline carbon particles, graphites, graphenes, - fluorinated carbons of the formula (CF _x ) _n wherein x is in the range 0.01 to 1.24 and n is in the range of y, up to 1000 - metals and metal alloys of metals selected from the group comprising 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, wherein 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 comprising Ti, V, Cr, Mn, Fe, Co, Cd, Ta, Ni, Cu, Zn, Zr, Nb, Mo, Sn and / or Al wherein 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, Alkali metal and alkaline earth metal titanates having the formula A _x Ti _y O ₄ or EA _{0.5 x} Ti _y O ₄ , where 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 O ₂ or EA _{x / 2} Cu _y O ₂ , where 0.8 ≤ x ≤ 1.2 and 0.7 ≤ y ≤ 1.25. Electrochemical cell according to one of the preceding claims, characterized in that the cation, in particular lithium, reversibly receiving and donating electrode material is usable at a potential in the range of 0.7 V to 2.2 V against lithium, preferably selected from the group comprising TiO ₂ , WO ₂ , MoO ₂ and / or Li ₄ Ti ₅ O ₁₂ . Electrochemical cell according to one of the preceding claims, characterized in that the conducting salt is selected from the group comprising ZF, ZCl, ZBr, ZI, ZPF ₆ , ZAsF ₆ , ZClO ₄ , ZNO ₃ , Z ₂ SO ₄ , ZSbF ₆ , ZPtCl ₆ , ZCN, Z (CF ₃ ) SO ₃ , ZC (SO ₂ CF ₃ ) ₃ , ZPF ₃ (CF ₃ ) ₃ , ZPF ₄ (C ₂ O ₄ ), ZBF ₄ , ZB (C ₂ O ₄ ) ₂ , ZBF ₂ (C ₂ O ₄ ), ZB (C ₂ O ₄ ) (C ₃ O ₄ ), Z (C ₂ F ₅ BF ₃ ), Z ₂ B ₁₂ F ₁₂ , ZN (SO ₂ F) ₂ , ZN (SO ₂ CF ₃ ) ₂ and / or ZN (SO ₂ C ₂ F ₅ ) ₂ , where Z is selected from the group comprising Li, Na, K and / or H. Use of an ionic liquid as a 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.

Images