WO2013084098A1 - Electrochemical cells comprising chelate ligands - Google Patents

Abstract

Electrochemical cells comprises (A) at least one cathode comprising at least one lithium ion-containing transition metal compound, (B) at least one anode, and (C) at least one layer comprising (a) at least one chemical compound which comprises at least one organic radical which derives from an organic chelate ligand, and (b) optionally at least one binder. The use of inventive electrochemical cells and lithium ion batteries comprising at least one inventive electrochemical cell are provided.

Description

 Electrochemical cells containing chelate ligands

Description The present invention relates to electrochemical cells containing

 (A) at least one cathode containing at least one lithium-ion-containing transition metal compound,

 (B) at least one anode, and

 (C) at least one layer containing

 (a) at least one chemical compound containing at least one organic radical derived from an organic chelating ligand, and

 (b) optionally at least one binder.

Furthermore, the present invention relates to the use of electrochemical cells according to the invention, and lithium-ion batteries, containing at least one electrochemical cell according to the invention.

Saving energy has long been an object of growing interest. Electrochemical cells, such as batteries or accumulators, can be used to store electrical energy. Of particular interest since recently the so-called lithium-ion batteries. They are superior in some technical aspects to conventional batteries. So you can create with them voltages that are not accessible with batteries based on aqueous electrolytes. In this case, the materials from which the electrodes are made, and in particular the material from which the cathode is made, play an important role.

In many cases, use is made of lithium-containing transition metal mixed oxides, in particular lithium-containing nickel-cobalt-manganese oxides having a layer structure, or manganese-containing spinels which may be doped with one or more transition metals. A problem of many batteries, however, remains the cycle stability, which is still to be improved. Especially in such batteries containing a relatively high proportion of manganese, for example in electrochemical cells with a manganese-containing spinel electrode and a graphite anode, one often observed a strong loss of capacity within a relatively short time. Furthermore, it can be seen that in cases where one selects graphite anodes as counterelectrodes, elemental manganese is deposited on the anode. It is envisioned that these manganese nuclei deposited on the anode have a potential of less than 1 V vs. Li / Li ^{+ act} as a catalyst for a reductive decomposition of the electrolyte. It should also be irreversibly bound lithium, causing the lithium-ion battery gradually loses capacity.

WO 2009/033627 discloses a sheet which can be used as a separator for lithium-ion batteries. It comprises a nonwoven as well as embedded in the nonwoven particles, which consist of organic polymers and optionally partly of inorganic material. By Although such separators can avoid short circuits caused by metal dendrites. In WO 2009/033627, however, no long-term cyclization experiments are disclosed.

WO 2009/103537 discloses a sheet having a base body having pores, the sheet further comprising a binder which is crosslinked. In a preferred embodiment, the main body is at least partially filled with particles. The disclosed layers can be used as separators in batteries. In WO 2009/103537, however, no electrochemical cells are produced and investigated with the layers described.

WO 201 1/024149 discloses lithium-ion batteries containing an alkali metal such as lithium between the cathode and anode, which serves as a scavenger of unwanted by-products or impurities and is referred to as a scavenger. Both in the production of the secondary battery cells and in a later recycling of the disused cells due to the presence of highly reactive alkali metal appropriate safety precautions must be taken.

The object was thus to provide electrical cells which have an improved service life and in which no deposition of elemental manganese has to be observed even after several cycles, or in whose production a scavenger can be used which has a lower safety problem than has the alkali metals and extends the life of the cell to the desired extent.

This object is achieved by an electrochemical cell as defined above, which comprises (A) at least one cathode containing at least one lithium-ion-containing transition metal compound,

 (B) at least one anode, and

 (C) at least one layer containing

 (a) at least one chemical compound containing at least one organic radical derived from an organic chelating ligand, and

 (b) optionally containing at least one binder.

The cathode (A) contains at least one lithium-ion-containing transition metal compound, such as, for example, the transition metal compounds L1CO 2, LiFePO ₄ or lithium manganese spinel known to those skilled in lithium-ion battery technology. Preferably, the cathode (A) contains as lithium ion-containing transition metal compound, a lithium ion-containing transition metal oxide containing manganese as the transition metal.

In the context of the present invention, lithium ion-containing transition metal oxides which contain manganese as transition metal are understood not only to be oxides which have at least one transition metal in cationic form but also those which have at least two transition metal oxides in cationic form. In addition, in the Within the scope of the present invention, such compounds are also included under the term "lithium ion-containing transition metal oxides" which, in addition to lithium, comprise at least one metal in cationic form, which is not a transition metal, for example aluminum or calcium.

In a preferred embodiment, manganese can occur in the cathode (A) in the formal oxidation state +4. More preferably, manganese occurs in cathode (A) in a formal oxidation state in the range +3.5 to +4. Many elements are ubiquitous. In certain very small proportions, for example, sodium, potassium and chloride can be detected in virtually all inorganic materials. In the context of the present invention, proportions of less than 0.1% by weight of cations or anions are neglected. A lithium ion-containing transition metal mixed oxide which contains less than 0.1% by weight of sodium is therefore considered to be sodium-free in the context of the present invention. Accordingly, a lithium ion-containing transition metal mixed oxide containing less than 0.1 wt .-% sulfate ions, in the context of the present invention as sulfate-free.

In one embodiment of the present invention, lithium ion-containing transition metal oxide is a transition metal mixed oxide containing at least one other transition metal in addition to manganese.

In one embodiment of the present invention, lithium ion-containing transition metal compound is selected from manganese-containing lithium iron phosphates and preferably from manganese-containing spinels and manganese-containing transition metal oxides having a layer structure, in particular manganese-containing transition metal mixed oxides having a layer structure.

In one embodiment of the present invention, lithium ion-containing transition metal compound is selected from those compounds having a more than stoichiometric amount of lithium.

wobei die Variablen wie folgt definiert sind: 0,9 < a < 1 ,3, bevorzugt 0,95 < a < 1 ,15, In one embodiment of the present invention, manganese-containing spinels are selected from those of the general formula (I)

where the variables are defined as follows: 0.9 <a <1, 3, preferably 0.95 <a <1, 15,

O s b s 0.6, for example 0.0 or 0.5,

where, in the case of choosing M ¹ = Ni, it is preferred that 0.4 <b ^ 0.55, -0.1 <d <0.4, preferably 0 <d <0.1,

M ¹ is selected from one or more elements selected from Al, Mg, Ca, Na, B, Mo, W, and transition metals of the first period of the periodic table of the elements. Preferably, M ^{1 is} selected from Ni, Co, Cr, Zn, Al, and most preferably M ^{1 is} Ni.

wobei die Variablen wie folgt definiert sind: In one embodiment of the present invention, manganese-containing spinels are selected from those of the formula LiNio.sMn-i.sC-d and LiM.sup.-C. In another embodiment of the present invention, manganese-containing transition metal oxides having a layer structure of those of the formula (II)

where the variables are defined as follows:

0 <t <0.3 and

M ² selected from Al, Mg, B, Mo, W, Na, Ca and transition metals of the first period of the periodic system of the elements, wherein the or at least one transition metal is manganese.

In one embodiment of the present invention, at least 30 mol% of M ^{2 are} selected from manganese, preferably at least 35 mol%, based on total content of M ² . In one embodiment of the present invention, M ^{2 is} selected from combinations of Ni, Co and Mn which contain no other elements in significant amounts.

In another embodiment, M ^{2 is} selected from combinations of Ni, Co and Mn which contain at least one further element in significant amounts, for example in the range from 1 to 10 mol% of Al, Ca or Na.

In one embodiment of the present invention, manganese-containing transition metal oxides having a layered structure are selected from those in which M ^{2 is} selected from Nio, 33Coo, 33Mno, 33, Ni ₀ , 5Coo, 2Mn ₀ , 3, Ni ₀ , 4Coo, 3Mn ₀ , 4, Ni ₀ , 4Coo, 2Mn ₀ , 4 and Ni ₀ , 45Coo, ioMn ₀ , 45.

In one embodiment, lithium-containing transition metal oxide is in the form of primary particles agglomerated into spherical secondary particles, the average particle diameter (D50) of the primary particles being in the range of 50 nm to 2 μm, and the mean particle diameter (D50) of the secondary particles being in the range of 2 μηη to 50 μηη lies.

Cathode (A) may contain one or more ingredients. For example, cathode (A) may contain carbon in conductive modification, such as graphite, carbon black, carbon nanotubes, graphene or mixtures of at least two of the aforementioned substances.

Furthermore, cathode (A) may contain one or more binders, also called binders, for example one or more organic polymers. Suitable binders are, for example, organic (co) polymers. Suitable (co) polymers, ie homopolymers or copolymers, can be selected, for example, from (co) polymers obtainable by anionic, catalytic or free-radical (co) polymerization, in particular from polyethylene, polyacrylonitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth) acrylonitrile and 1,3-butadiene, in particular styrene-butadiene

Copolymers. In addition, polypropylene is suitable. Furthermore, polyisoprene and polyacrylates are suitable. Particularly preferred is polyacrylonitrile.

In the context of the present invention, polyacrylonitrile is understood to mean not only polyacrylonitrile homopolymers, but also copolymers of acrylonitrile with 1,3-butadiene or styrene. Preference is given to polyacrylonitrile homopolymers.

In the context of the present invention, polyethylene is understood to mean not only homo-polyethylene, but also copolymers of ethylene which contain at least 50 mol% of ethylene and up to 50 mol% of at least one further comonomer, for example α-olefins such as Propylene, butylene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, furthermore isobutene, vinylaromatics such as styrene, for example

(Meth) acrylic acid, vinyl acetate, vinyl propionate, Ci-Cio-alkyl esters of (meth) acrylic acid, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, further maleic acid, maleic anhydride and itaconic. Polyethylene may be HDPE or LDPE.

In the context of the present invention, polypropylene is understood to mean not only homo-polypropylene but also copolymers of propylene which contain at least 50 mol% of propylene polymerized and up to 50 mol% of at least one further comonomer, for example ethylene and α-propylene. Olefins such as butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 1-pentene. Polypropylene is preferably isotactic or substantially isotactic polypropylene.

In the context of the present invention, polystyrene is understood to mean not only homopolymers of styrene, but also copolymers with acrylonitrile, 1,3-butadiene, (meth) acrylic acid, C 1 -C 10 -alkyl esters of (meth) acrylic acid, divinylbenzene, in particular 1, 3. Divinylbenzene, 1, 2-diphenylethylene and a-methylstyrene.

Another preferred binder is polybutadiene. Other suitable binders are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimides and polyvinyl alcohol.

In one embodiment of the present invention, binders are selected from those (co) polymers which have an average molecular weight M _w in the range from 50,000 to 1,000,000 g / mol, preferably up to 500,000 g / mol.

Binders may be crosslinked or uncrosslinked (co) polymers. In a particularly preferred embodiment of the present invention, binders are selected from halogenated (co) polymers, in particular from fluorinated (co) polymers. Halogenated or fluorinated (co) polymers are understood as meaning those (co) polymers which contain at least one (co) monomer in copolymerized form which has at least one halogen atom or at least one fluorine atom per molecule, preferably at least two halogen atoms or at least two fluorine atoms per molecule.

Examples are polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymers, perfluoroalkylvinyl ether copolymers, ethylene-tetrafluoroethylene copolymers, vinylidene fluoride copolymers. Chlorotrifluoroethylene copolymers and ethylene-chlorofluoroethylene copolymers.

Suitable binders are in particular polyvinyl alcohol and halogenated (co) polymers, for example polyvinyl chloride or polyvinylidene chloride, in particular fluorinated (co) polymers such as polyvinyl fluoride and in particular polyvinylidene fluoride and polytetrafluoroethylene.

Furthermore, cathode (A) may have further conventional components, for example a current conductor, which may be configured in the form of a metal wire, metal grid, metal mesh, expanded metal, metal sheet or a metal foil. Aluminum foils are particularly suitable as metal foils.

In one embodiment of the present invention, cathode (A) has a thickness in the range of 25 to 200 μηη, preferably from 30 to 100 μηη, based on the thickness without Stromableiter.

Inventive electrochemical cells also contain at least one anode (B).

In one embodiment of the present invention, anode (B) may be selected from anodes of carbon and anodes containing Sn or Si. For example, carbon anodes may be selected from hard carbon, soft carbon, graphene, graphite, and especially graphite, intercalated graphite, and mixtures of two or more of the aforementioned carbons. For example, anodes containing Sn or Si can be selected from nanoparticu- Si- or Sn powder, Si or Sn fibers, carbon-Si or carbon-Sn composites and Si-metal or Sn-metal alloys.

Anode (B) may comprise one or more binders. In this case, one can choose as binder one or more of the abovementioned binders, which are mentioned in the context of the description of the cathode (A).

Furthermore, anode (B) may have further conventional components, for example a current conductor, which may be designed in the form of a metal wire, metal grid, metal mesh, expanded metal, or a metal foil or a metal sheet. As metal foils in particular copper foils are suitable.

In one embodiment of the present invention, anode (B) has a thickness in the range from 15 to 200 μm, preferably from 30 to 100 μm, based on the thickness without current conductors.

Electrochemical cells according to the invention furthermore contain (C) at least one layer, also referred to as layer (C) for short, which contains (a) at least one chemical compound, in short also compound (a) which contains at least one organic radical which differs from a derives from organic chelating ligand, and (b) optionally at least one binder, also called binder (b) for short.

The chemical compound contained in layer (C) may, for example, be an organic chelating ligand itself or preferably an organic or inorganic polymer, in which case this organic or inorganic polymer contains at least one organic radical which is derived from an organic chelating ligand.

In a preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that the chemical compound contained in layer (C) is an organic or inorganic polymer, which is also referred to below as polymer (a).

Polymer (a), which may be organic or inorganic in nature, is known in principle to the person skilled in the art. Preferably, polymer (a) is selected from those polymers which are not compatible with the other components of the electrochemical cell with which they may come into contact, such as the liquid electrolyte, that is, at least one organic solvent and the ions of the at least one conducting salt cause unwanted side reactions. Side reactions usually have a negative effect on the cycle stability and the capacity of the electrochemical cell. Suitable polymers are already used, for example, as constituents of separators in batteries or as binders in electrodes for electrochemical cells. The preferred polymers (a) are not soluble in the liquid electrolyte of the electrochemical cell at room temperature. In a preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that the chemical compound contained in layer (C) is selected from the group consisting of polyvinylpyrrolidone, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, melamine-formaldehyde resins, polysulfones, polyethersulfo- ne and substituted styrene-divinylbenzene copolymers and S1O2, Al2O3, ΤΊΟ2, ZrÜ2 and mixtures thereof.

Depending on the properties of the organic or inorganic polymer discussed above in layer (C), this polymer may be present in different form in layer (C). An inorganic polymer such as S1O2 (for example silica gel), Al2O3, ΤΊΟ2, ZrÜ2 and mixtures thereof is usually present in particulate form. In principle, it is also possible to produce silicon dioxide in the form of thin layers, ie as films, from suitable starting compounds, although such a film must also have pores through which the electrolyte fluid and lithium cations can migrate unhindered. An organic polymer such as polyvinylpyrrolidone, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, melamine-formaldehyde resins, polysulfones, polyethersulfones and substituted styrene-divinylbenzene copolymers may be incorporated in different forms in layer (C) depending on the profile of properties. An insoluble organic polymer such as crosslinked styrene-divinylbenzene copolymer is preferably incorporated in the form of particles in layer (C), while a corresponding soluble polymer can be processed into a film, for example a polyethersulfone, or else homogeneously in the layer (C). For example, on or in a carrier material, which in turn may be organic or inorganic origin can be applied.

In cases where an organic chelating ligand itself is the chemical compound contained in layer (C), the organic chelate ligand, which is preferably a low-molecular weight compound, that is, preferably a compound having a molecular weight of less than 2,000 g / mol, more preferably having a molecular weight of 60 g / mol to 1000 g / mol, in different form in layer (C). Depending on the solubility properties of the chelating ligand in the electrolyte liquid, it may be completely, largely or hardly dissolved therein and thus homogeneously distributed in layer (C) and / or in particulate form.

In one embodiment of the present invention, the inventive electrochemical cells are characterized in that the chemical compound contained in layer (C), in particular the organic or inorganic polymer contained in layer (C), in particulate form, in the form of a film or is homogeneously distributed in layer (C). The polymer contained in layer (C) is preferably present in particulate form. In the context of the present invention, organic or inorganic polymers in particulate form can have an average particle diameter (D50) in the range from 0.05 to 100 μm. Organic polymers preferably have an average particle diameter (D50) in the range from 0.5 to 10 μm, more preferably from 2 to 6 μm. Inorganic polymers preferably have one average particle diameter (D50) in the range of 0.05 to 5.0 μηη, particularly preferably from 0.1 to 2 μηη.

The organic radical contained in the chemical compound, in particular in the organic or inorganic polymer, is derived from an organic chelating ligand.

In the context of the present invention, an organic radical is understood to be one which is derived in each case from an organic compound. Thus, three different organic radicals with one carbon atom are derived from the organic compound methanol, namely methyl (H ₃ C-), methoxy (H ₃ C-O-) and hydroxymethyl (HOC (H ₂ ) -). The organic residue is therefore to be regarded as a partial structure of the parent organic starting compound. The organic radical preferably has the same linkage of carbon atoms (carbon skeleton) as the starting organic compound, in particular, the organic radical has the same number of carbon atoms as the organic compound.

Organic chelating ligands have two or more coordination sites for metal cations, wherein preferably two coordination sites of the organic chelating ligand together with a metal cation, preferably a transition metal cation, can form a stress-free 5- or 6-membered ring. Such metal complexes are called chelate complexes. In the chelate complex, the organic chelating ligand may itself be present as a neutral constituent, for example 2,2'-bipyridine, or in mono- or multiply deprotonated form, for example as oxinate or tartrate. In a preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that the organic radical contained in the chemical compound, in particular in the organic or inorganic polymer is derived from an organic chelating ligand selected from the group of chelating ligands consisting of acetylacetone and its salts, salicylimide and its salts, Ν, Ν'-ethylenebis (salicylimine) and its salts, ethylenediamine, 2- (2-aminoethylamino) ethanol, diethylenetriamine, iminodiacetic acid and its salts, triethylenetetramine, triaminotriethylamine, nitrilotriacetic acid and their Salts, ethylenediaminotriacetic acid and its salts, ethylenediaminetetraacetic acid and its salts, diethylenetriaminepentaacetic acid and its salts, 1, 4,7,10-tetraazacyclododecane-1, 4,7,10-tetraacetic acid and its salts, oxalic acid and its salts, tartaric acid and their salts, citric acid and its salts, dimethylglyoxime, 8-hydroxy quinoline and its salts, dimercaptosuccinic acid and its salts, 2,2'-bipyridine, 1, 10-phenanthroline, and substituted derivatives thereof, that is, derivatives of all the foregoing chelating ligands. In accordance with the invention, polydentate chelate ligands which can form more than one stress-free 5- or 6-membered ring with a metal ion, in particular a multiply charged transition metal ion, such as, for example, Mn ²⁺ , are preferred. Particularly preferred are tetradentate Chelate ligands, especially those of the salt type with the main body Ν, Ν'-ethylenebis (salicylimine).

Many of the chelating ligands have acidic protons that can be deprotonated with appropriate bases, for example, alkali metal hydroxides such as lithium hydroxide or sodium hydroxide, alkali metal hydrides such as lithium hydride or sodium hydride, or alkyl alkali metal compounds such as methyl or butyllithium. The acidic protons of the chelating ligands can be derived, for example, from carboxy groups (-COOH), as in the case of ethylenediaminetetraacetic acid, or hydroxy groups (-OH), as in the case of salicylimides. Double negatively charged chelating ligands form neutral complexes with doubly positively charged metal ions, which are also called internal complexes. When lithiated chelating ligands are used, the coordination of multiply charged transition metal ions liberates singly charged lithium ions, which provide the required charge transport in lithium-ion cells.

In a further preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that the organic radical contained in the chemical compound, in particular in the organic or inorganic polymer, is derived from an organic chelating ligand in which one or more acidic protons are replaced by lithium cations were exchanged.

As described above, the chemical compound, especially the organic or inorganic polymer, contains at least one organic radical derived from an organic chelating ligand.

In one embodiment of the present invention, the organic radical derived from an organic chelating ligand, also referred to below as the chelating ligand moiety, is covalently bound to the chemical compound, in particular the organic or inorganic polymer. The linkage between chelate ligand radical and chemical compound, in particular organic or inorganic polymer, can be effected directly via at least one, preferably a chemical bond or via at least one, preferably a linker, a so-called linker, wherein the linker is a bi- or more-bonded atom, for example O- or -Si (Me) 2-, or a two- or mehrbindige organic group, such as -CH2CH2- or -0 (C = 0) 0 can be.

In one variant, a suitably substituted chelating ligand or its salt can be covalently bound to an organic or inorganic polymer, optionally synthesized with specific functional groups for linking. In J. Am. Chem. Soc. 1999, 121, 4147-4154, methods are shown with which chiral salen ligands can be linked to a hydroxymethylpolystyrene, or can be covalently supported on silica gel. Catalysis Letters Vol. 81, No, 1-2, 89-96 describes the preparation of a silica gel carrying covalently bonded ethylenediaminetriacetic acid groups. In Adv. Synth. Catal. 2006, 348, 1760-1771, the introduction mentions a series of salde complexes supported on different polymers which represent different support concepts for the preparation of organic polymers containing at least one residue derived from an organic chelating ligand. In Langmuir, Vol. 23, no. 9, 2007, 5062-5069 describes the preparation of poly (N-salicylidene-vinylamine) by reacting polyvinylamine with salicylaldehyde.

In a further variant, a chelate ligand may also be incorporated into the main chain of a polymer itself, as in the case of a polymeric chiral salen ligand in J. Mol. Catal.

A: Chem. 259 (2006), 125-132.

In a specific variant, as already described above, the chemical compound (a) itself may be a low molecular weight organic chelate ligand. In this case, the residue derived from a chelating ligand is covalently bound to the chemical compound, namely to the organic chelating ligand.

In a preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that the organic radical derived from an organic chelating ligand is covalently bound to the chemical compound, in particular covalently bonded to the organic or inorganic polymer.

In a further embodiment of the present invention, the organic radical derived from an organic chelating ligand is bound by absorption to the chemical compound, in particular to the organic or inorganic polymer. In this embodiment, the chelate ligand moiety is part of an organic chelating ligand or component of a soluble polymer. Since organic chelating ligands usually contain at least two polar groups, organic chelating ligands may be preferred to polar organic or inorganic polymers, such as silica gels (S1O2), melamine-formaldehyde resins, such as the foamed thermoset Basotect®, PVP in soluble or insoluble form or form strong interactions with the corresponding copolymers of vinylpyrrolidone, for example with vinyl acetate or with vinylcaprolactam. In this way, organic chelating ligands can be bound by adsorption, that is to say without covalent bonds, on a suitable organic or inorganic polymer. For example, the separators described in WO 2009/033627 or WO 2009/103537, which contain particles of polar inorganic and / or organic polymers, such as, for example, silica, alumina or polyvinylpyrrolidone, can be treated with a solution of a chelating ligand, for example a salender derivative For example, by impregnation or spraying, to arrive at a modified separator with which an electrochemical cell according to the invention can be produced. For example, the separator described in Example 2 of WO 2009/103537 can be treated with the solution of a chelating ligand, in particular of a salt derivative. In a further preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that the organic radical derived from an organic chelating ligand is bound by absorption to the chemical compound, in particular to the organic or inorganic polymer.

The proportion by weight of the chemical compound (a), in particular of the polymer (a), of the total mass of the layer (C) can be up to 100% by weight. The proportion by weight of the polymer (a) in the total mass of the layer (C) is preferably at least 5% by weight, particularly preferably 40-80% by weight, in particular the weight fraction of the polymer (a) is based on the total mass of the layer ( C) in the range of 30 to 50 wt .-%.

The proportion by weight of the organic radical derived from an organic chelating ligand may also be up to 100% by weight relative to the total weight of the layer (C). The proportion by weight of the chelate ligand radical in the total mass of the layer (C) is preferably at least 1% by weight, more preferably 5 to 50% by weight, in particular the proportion by weight of the chelate ligand radical in the total mass of the layer (C) is in the region of 10 to 30% by weight.

In one embodiment of the present invention, binder (b) is selected from such binders as described in connection with binder for the cathode (s) (A).

In a preferred embodiment of the present invention, the electrochemical cell according to the invention is characterized in that layer (C) contains a binder (b) selected from the group of polymers consisting of polyvinyl alcohol, styrene-butadiene rubber, polyacrylonitrile, carboxymethyl cellulose and fluorine-containing (Co) polymers, in particular selected from styrene-butadiene rubber and fluorine-containing (co) polymers.

In one embodiment of the present invention, binder (b) and binder for cathode and for anode, if present, are the same.

In another embodiment, binder (b) differs from binder for cathode (A) and / or binder for anode (B), or binder for anode (B) and binder for cathode (A) are different. In one embodiment of the present invention, layer (C) has an average thickness in the range from 0.1 μm to 250 μm, preferably from 1 μm to 100 μm, particularly preferably from 9 μm to 50 μm.

Layer (C) is preferably a layer which does not conduct the electric current, that is to say an electrical insulator. On the other hand, layer (C) is preferably a layer which permits the migration of ions, in particular of ions. Layer (C) is preferably arranged spatially between the cathode and the anode within the electrochemical cell according to the invention. In electrochemical cells, the direct, short-circuiting contact of the anode with the cathode is usually prevented by the installation of a separator.

In a further embodiment of the present invention, the electrochemical cells according to the invention are characterized in that layer (C) is a separator.

Layer (C) may contain, in addition to the chemical compound (a) containing at least one organic radical derived from an organic chelating ligand, and the optional binder (b) further constituents, for example, supporting material such as fibers or nonwovens, which are improved Stability of layer (C), without affecting their necessary porosity and ion permeability. Alternatively or additionally, layer (C) may also contain at least one porous plastic layer, for example a polyolefin membrane, in particular a polyethylene or a polypropylene membrane. In turn, polyolefin membranes can be composed of one or more layers. Porous polyolefin membranes or nonwovens themselves can usually fulfill the function of a separator alone. Also, layer (C) may contain particles of inorganic or organic nature, which are mentioned, for example, in WO 2009/033627. In one embodiment of the present invention, the electrochemical cells according to the invention are characterized in that layer (C) additionally contains a nonwoven (c).

Fleece (c) may be made of inorganic or organic materials. Examples of organic nonwovens are polyester nonwovens, in particular polyethylene terephthalate nonwovens (PET nonwovens), polybutylene terephthalate nonwovens (PBT nonwovens), polyimide nonwovens, polyethylene and polypropylene nonwovens, PVdF nonwovens and PTFE nonwovens. Preference is given in particular to PET webs. Examples of inorganic nonwovens are glass fiber nonwovens and ceramic fiber nonwovens.

Depending on the composition of the layer (C), it may be prepared, for example, solely from the chelate ligand-modified chemical compound (a), for example in the form of a porous film, or from the modified chemical compound (a) in particulate form and a binder (b) or also of a polyester nonwoven with particles of the chelate ligand-modified chemical compound (a) uniformly distributed therein, wherein the chemical compound is preferably an organic or inorganic polymer. In these cases, layer (C) itself can already be used as a separator in the electrochemical cell according to the invention and can thus cover the cathode (A) or the anode (B) on at least one side. Furthermore, a layer (C) can also be applied to a commonly usable battery separator, such as a porous polyolefin membrane or a nonwoven, so that layer (C) covers a separator on at least one side. Layer (C) can also be called thin layer are applied to the cathode or anode and the electrochemical cell according to the invention thus produced additionally contain a porous polyolefin membrane as a separator. In a further variant, layer (C) can also largely consist of particles of a polymer as carrier material, the polymer particles being coated with the chemical compound (a) modified with chelate ligand dries

In a further embodiment of the present invention, the electrochemical cells according to the invention are characterized in that layer (C) covers the cathode (A) or a separator or the anode (B) on at least one side.

Another object of the present invention is the use of a chemical compound containing at least one organic radical derived from an organic chelating ligand for the preparation of an electrochemical cell. The correspondingly modified with organic chelating ligands chemical compounds (a), ie organic chelating ligands themselves, organic or inorganic polymers and electrochemical cells, have already been described above. The present invention accordingly also provides a process for producing an electrochemical cell comprising at least one cathode and at least one anode, in which at least one chemical compound which contains at least one organic radical which is derived from an organic chelating ligand is present in one layer ( C) between the cathode and anode positioned, that is installed. Various embodiments for providing and composing the modified chemical compound, in particular a modified organic or inorganic polymer have been presented above. Accordingly, another object of the present invention is also the use of an organic or inorganic polymer containing at least one organic radical derived from an organic chelating ligand for the preparation of an electrochemical cell. As stated above, an organic chelating ligand may be bonded by absorption to an organic or inorganic polymer, or organic moieties derived from an organic chelating ligand are covalently bonded to an organic or inorganic polymer. Another object of the present invention is also a process for producing an electrochemical cell comprising at least one cathode and at least one anode, wherein at least one organic or inorganic polymer containing at least one organic radical derived from an organic chelating ligand, in a layer positioned between the cathode and the anode, that is to say installed. Various embodiments for providing and composing the modified organic or inorganic polymer have been presented above.

The layer (C) contained in the electrochemical cell according to the invention can also be produced independently of the assembly of the electrochemical cell according to the invention as a semifinished product and later by a battery manufacturer as part of an electrochemical cell, for example as a finished separator or together. with a typical battery separator, such as a PET nonwoven or a porous polyolefin membrane, between the cathode and anode in an electrochemical cell.

Electrochemical cells according to the invention may further comprise conventional constituents, for example conductive salt, nonaqueous solvent, furthermore cable connections and housing.

In one embodiment of the present invention, electrochemical cells according to the invention contain at least one non-aqueous solvent, which may be liquid or solid at room temperature, preferably liquid at room temperature, and which is preferably selected from polymers, cyclic or non-cyclic ethers, cyclic or not cyclic acetals, cyclic or non-cyclic organic carbonates and ionic liquids. Examples of suitable polymers are in particular polyalkylene glycols, preferably P0IV-C1-C4-alkylene glycols and in particular polyethylene glycols. Polyethylene glycols may contain up to 20 mol% of one or more C 1 -C 4 -alkylene glycols in copolymerized form. Preferably, polyalkylene glycols are polyalkylene glycols double capped with methyl or ethyl.

The molecular weight M _w of suitable polyalkylene glycols and especially of suitable polyethylene glycols may be at least 400 g / mol.

The molecular weight M _w of suitable polyalkylene glycols and in particular of suitable polyethylene glycols may be up to 5,000,000 g / mol, preferably up to 2,000,000 g / mol

Examples of suitable non-cyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1, 2-dimethoxyethane, 1, 2-diethoxyethane, preference is 1, 2-dimethoxyethane.

Examples of suitable cyclic ethers are tetrahydrofuran and 1,4-dioxane.

Examples of suitable non-cyclic acetals are, for example, dimethoxymethane,

Diethoxymethane, 1, 1-dimethoxyethane and 1, 1-diethoxyethane.

Examples of suitable cyclic acetals are 1, 3-dioxane and in particular 1, 3-dioxolane.

Examples of suitable non-cyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate. Examples of suitable cyclic organic carbonates are compounds of the general formulas (X) and (XI)

bei denen R¹, R² und R³ gleich oder verschieden sein können und gewählt aus Wasserstoff und Ci-C4-Alkyl, beispielsweise Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec.-Butyl und tert.-Butyl, wobei vorzugsweise R² und R³ nicht beide tert.-Butyl sind.

in which R ¹ , R ² and R ^{3 may be} identical or different and selected from hydrogen and C 1 -C 4 -alkyl, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec. Butyl and tert-butyl, preferably R ² and R ^{3 are} not both tert-butyl.

In particularly preferred embodiments, R ^{1 is} methyl and R ² and R ³ are each hydrogen, or R ¹ , R ² and R ³ are each hydrogen.

Another preferred cyclic organic carbonate is vinylene carbonate, formula (XII).

O

} X o

 \ = J

Preferably, the solvent or solvents are used in the so-called anhydrous state, i. with a water content in the range of 1 ppm to 0.1 wt .-%, determined for example by Karl Fischer titration.

Inventive electrochemical cells also contain at least one conductive salt. Suitable conductive salts are in particular lithium salts. Examples of suitable lithium salts are LiPF ₆ , LiBF ₄ , UCIO ₄ , LiAsF ₆ , UCF 3 SO 3, LiC (CnF _{2n +} iSO 2) 3, lithium imides such as LiN (CnF ₂ n ₊ iSO ₂ ) ₂ , where n is an integer in the range of 1 to 20 , LiN (SO 2 F) 2, Li 2 SiFe, LiSbF 6, LiAICU, and salts of the general formula (C _n F 2n + i SO 2) m X Li, where m is defined as follows:

m = 1, if X is selected from oxygen and sulfur,

m = 2 when X is selected from nitrogen and phosphorus, and

m = 3, when X is selected from carbon and silicon.

Preferred conductive salts are selected from LiC (CF ₃ SO ₂ ) ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiPF ₆ , LiBF ₄ , LiCl ₄ , and particularly preferred are LiPF 6 and LiN (CF 2 SO 2) 2. Electrochemical cells according to the invention furthermore contain a housing which can have any shape, for example cuboid or the shape of a cylinder. In another embodiment, electrochemical cells according to the invention have the shape of a prism. In one variant, a metal-plastic composite film prepared as a bag is used as the housing.

Inventive electrochemical cells provide a high voltage of up to about 4.8 V and are characterized by a high energy density and good stability. In particular, electrochemical cells according to the invention are characterized by only a very small loss of capacity during repeated cycling.

Another object of the present invention is the use of electrochemical cells according to the invention in lithium-ion batteries. Another object of the present invention are lithium-ion batteries, containing at least one electrochemical cell according to the invention. Inventive electrochemical cells can be combined with one another in lithium-ion batteries according to the invention, for example in series connection or in parallel connection. Series connection is preferred.

Another object of the present invention is the use of inventive electrochemical cells as described above in automobiles, powered by electric motor two-wheelers, aircraft, ships or stationary energy storage.

Another object of the present invention is therefore also the use of lithium-ion batteries according to the invention in devices, in particular in mobile devices. Examples of mobile devices are vehicles, for example automobiles, two-wheeled vehicles, aircraft or watercraft, such as boats or ships. Other examples of mobile devices are those that you move yourself, such as computers, especially laptops, phones or electrical tools, for example, in the field of construction, in particular drills, cordless screwdrivers or cordless tackers.

The use of lithium-ion batteries in devices according to the invention offers the advantage of a longer running time before recharging as well as a lower capacity loss with a longer running time. If one wanted to realize an equal running time with electrochemical cells with a lower energy density, then one would have to accept a higher weight for electrochemical cells.

The invention is illustrated by the following, but not limiting examples of the invention. Percentages are by weight in each case, unless expressly stated otherwise. I. Preparation of chelated ligand-modified chemical compounds 1.1 Synthesis of N, N-bis (4-hydroxysalicylidene) ethylene-1,2-diamine

Ethylenediamine (3.0 g, 50 mmol) was charged with ethanol (200 mL) in a 250 mL stirred condenser with reflux condenser, thermometer, dropping funnel. With stirring, 2,4-dihydroxybenzaldehyde (13.8 g, 100 mmol) was added dropwise. This resulted in a yellow suspension. This suspension was stirred for 3 more days at RT, then filtered off with suction, the residue was washed with ethanol and then dried in vacuo to give the product as a yellow powder (14.3 g, 95% yield).

 H NMR (DMSO-de): δ = 8.35 (s, 2H, HCN), 7.15 (d, 2H, ArH), 6.25 (d, 2H, ArH), 6.15 (s, 2H , ArH ortho), 3.75 (s, 4H, alk-H).

I.2 Synthesis of Tetralithium Alcoholate of N, N-bis (4-hydroxysalicylidene) ethylene-1,2-diamine

A 250 ml stirred flask with magnetic stirrer, reflux condenser, dropping funnel, and thermometer was thoroughly inertized with argon. N, N-bis (4-hydroxysalicylidene) ethylene-1,2-diamine (6.00 g, 20 mmol) from Example 1.1 was initially charged in dry THF (200 ml) at -70 ° C. While stirring, butyllithium (1.6 M in n-hexane, 50 ml, 80 mmol) was slowly added dropwise. Then the mixture was allowed to come to RT overnight (18 hrs.). The whole was evaporated and pulled dry in vacuo. The product was isolated as a 14.0 g hygroscopic gelborane solid which still contained THF in the form of Li-THF complex. H NMR (MeOD): δ = 7.68 (s, 2H, HCN), 6.77 (d, 9Hz, 2H, ArH), 5.95 (d, 9Hz, 2H, ArH), 5.83 (s, 2H ArH), 3.65 (s, 4H, alkylH); + 3.72 (m, = THF), 1.86 (m = THF). I.3 Synthesis of Dilithium Alcoholate of N, N-bis (4-hydroxysalicylidene) ethylene-1,2-diamine

 A 250 ml stirred flask with magnetic stirrer, reflux condenser, dropping funnel, and thermometer was thoroughly inertized with argon. N, N-bis (4-hydroxysalicylidene) ethylene-1,2-diamine (6.00 g, 20 mmol) from Example 1.1 was initially charged in dry THF (200 ml) at -70 ° C. While stirring, butyl lithium (1, 6 M in n-hexane, 25 ml, 40 mmol) was slowly added dropwise. The mixture was then allowed to come to RT overnight (18 h). The whole was evaporated and pulled dry in vacuo. 8.4 g of a yellow-orange solid were isolated, which still contained THF in the form of Li-THF complex. H NMR (MeOD): δ = 7.68 (s, 2H), 6.82 (d, 9Hz, 2H), 6.00 (d, 9Hz, 2H), 3.69 (s, 4H); + 3.72 (m = THF), 1.86 (m = THF).

I.4 Synthesis of an unsymmetrical salen ligand

3.0 g of ethylenediamine (50 mmol) and 6.6 g of ethylenediammonium dichloride (50 mmol) were placed in a 500 ml stirred apparatus with reflux condenser, thermometer and dropping funnel in 150 ml of ethanol. The dihydrochloride was difficult to dissolve. Thereafter, the suspension was heated to 60 ° C, wherein the dihydrochloride did not dissolve completely. The suspension was diluted with a further 100 ml of ethanol and stirred at 60 ° C, where still some crystals were seen. 6.1 g of salicylaldehyde (50 mmol) were added to this "solution" of monohydrochloride at RT and the mixture was stirred overnight, To the yellow suspension was added a solution of 9.6 g of 5-allyl-2-hydroxy-3-methoxybenzaldehyde (50 mmol) and 10.1 g of triethylamine (100 mmol) in 100 ml of ethanol were stirred in. The mixture was stirred overnight and the mixture was rotary evaporated to give a residue which was still moist with solvent and which also contained triethylamine hydrochloride The residue was treated with 20 ml of water and extracted three times with 300 ml of toluene each time The combined toluene phases were rotary evaporated to give 17.8 g of a red oil. H NMR (acetonitrile-ds): δ = 13.3-13.5 (d, 2H, ArOH), 8.45 (s, 1H, HCN), 8.35 (s, 1H, HCN), 7 , 10-7.35 (m, 4H, (2H ArH + 2H impurity), 6.80-6.92 (m, 3H, ArH), 6.73 (s, 1H, ArH), 5.90- 6.00 (m, 1H, -CH ₂ -CH = CH ₂ ), 5.00-5.10 (t, 2H, -CH ₂ -CH = CH ₂ ), 3.90 (t, 4H, alkylH ), 3.78 (s, 3H, OCH ₃ ), 3.30 (d, 2H, -CH ₂ -CH = CH ₂ ).

I.5 Synthesis of 3-allylpentane-2,4-dione

In a 250 ml stirred apparatus with reflux condenser, thermometer and dropping funnel 40.5 g of a 30% solution of sodium methylate in methanol (225 mmol) in 100 ml of methanol were presented, and at about 5 ° C were 20.0 g Acetylacetone (200 mmol) was added dropwise. The reaction mixture was allowed to come to room temperature. Subsequently, 40.3 g of allyl iodide (240 mmol) were added dropwise. The mixture was stirred at room temperature overnight. Sales control by GC showed only few starting materials. The precipitate was filtered off and the filtrate evaporated to about 100 ml. The solution was treated with MTBE-hexane 1: 1, the precipitate formed filtered off again and the solution was evaporated again to about 100 ml. This procedure was repeated with the solvent mixture MTBE-hexane-heptane 1: 1: 1. Subsequently, the low boilers were distilled off via a short column at about 160 mbar. The product was distilled at 32 mbar and 95-100 ° C. There were obtained 7.8 g of product. Product is present as a tautomer (-2: 1 keto: enol), therefore, see in NMR as a mixture. H NMR (DMSO-de): δ = 5.95-5.50 (m, 1H, HC = CH ₂ ), 5.10-4.95 (m, 2H, HC = CH ₂ ), 3.98 (t, ~ 0.6H, CH (CO) keto), 3.00 (d, ~ 0.7H, CH ₂ HC = CH ₂ enol), 2.45 (t, ~ 1, 3H, CH ₂ HC = CH ₂ keto), 2.17 (s, ~ 4H, CH ₃ keto), 2.10 (s, ~ 2H, CH ₃ enol). II. Production of Separators According to the Invention

11.1 Method for producing a separator according to the invention (S.1)

1 g of the tetra-lithium salt of N, N-bis (4-hydroxysalicylidene) - ethylene-1, 2-diamine prepared in Example I.2 is dissolved in 4 g of water. With this solution, a separator based on cross-linked polyvinylpyrrolidone and a PET nonwoven fabric (4 cm × 8 cm, prepared according to Example 2 from WO2009 / 103537 A1) is impregnated by a single immersion. The modified separator is dried in air overnight. III. Production of electrochemical cells and their testing

The following electrodes are always used: Cathode (A.1): lithium-nickel-manganese spinel electrodes are used, which are prepared as follows. You mix with each other:

85% LiMni, ₅ Ni ₀ , ₅ O4,

6% PVdF, commercially available as Kynar Flex ^® 2801 Arkema Group,

6% carbon black, BET surface area of 62 m ² / g, commercially available as "Super P Li" from Timcal, 3% graphite, commercially available as KS6 from Timcal;

in a screw-in container. While stirring, it is mixed with so much N-methyl-pyrrolidone until a viscous lump-free paste is obtained. It is stirred for 16 hours.

Then the resulting paste is rakelt on 20 μηη thick aluminum foil and dried for 16 hours in a vacuum oven at 120 ° C. The thickness of the coating is usually 30 μηη after drying. Then you punch out circular disk-shaped segments with a diameter of 12 mm.

Anode (B.1): Mix with each other

91% graphite ConocoPhillips C5,

6% PVdF, commercially available as Kynar Flex ^® 2801 Arkema Group,

3% carbon black, BET surface area of 62 m ² / g, commercially available as "Super P Li" from Timcal in a screw-on vessel, stirring with so much N-methyl-pyrrolidone until a tough, lump-free paste is obtained It is stirred for 16 hours.

Then the resulting paste is rakelt on 20 μηη thick copper foil and dried for 16 hours in a vacuum oven at 120 ° C. The thickness of the coating is usually 35 μηη after drying. Then you punch out circular disk-shaped segments with a diameter of 12 mm.

You always use the following electrolytes:

 1 M solution of LiPF6 in anhydrous ethylene carbonate-ethylmethyl carbonate mixture (parts by weight 1: 1) 111.1 Method for producing an electrochemical cell EZ.1 according to the invention and testing

The separator (S.1) according to the invention produced according to 11.1 is used as a separator and dripped with electrolyte in an argon-filled glove box and positioned between a cathode (A.1) and an anode (B.1), so that both the anode as well as the cathode have direct contact to the separator. It sets to electrolyte and receives an inventive electrochemical cell EZ.1. The electrochemical examination is carried out between 4.25 V and 4.8 V in an electrochemical cell.

The first two cycles are run at 0.2C rate for formation; Cycles # 3 through # 50 are cycled at 1 C rate, followed by another 2 cycles at 0.2C rate followed by 48 cycles at 1 C rate, etc. Charging or discharging the cell is accomplished with the help of a "MACCOR Battery Tester" performed at room temperature.

FIG. 1 shows the schematic structure of a disassembled electrochemical cell for testing separators according to the invention and not according to the invention.

The explanations in FIG. 1 mean:

1, 1 'stamp

2, 2 'mother

 3, 3 'sealing ring - each double, the second, slightly smaller sealing ring is not shown here

 4 spiral spring

 5 current conductors made of nickel

6 housing

Claims

claims Electrochemical cell containing (A) at least one cathode containing at least one lithium-ion-containing transition metal compound,  (B) at least one anode, and  (C) at least one layer containing  (a) at least one chemical compound containing at least one organic radical derived from an organic chelating ligand, and  (b) optionally at least one binder. Electrochemical cell according to Claim 1, characterized in that the lithium-ion-containing transition metal compound contained in cathode (A) is selected from manganese-containing spinels and manganese-containing transition metal oxides having a layer structure. Electrochemical cell according to claim 1 or 2, characterized in that anode (B) is selected from anodes of carbon and anodes containing Sn or Si. An electrochemical cell according to any one of claims 1 to 3, characterized in that the chemical compound contained in layer (C) is an organic or inorganic polymer. Electrochemical cell according to one of claims 1 to 4, characterized in that the chemical compound contained in layer (C) is selected from the group consisting of polyvinylpyrrolidone, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, melamine-formaldehyde resins, polysulfones, polyethersulfones and substituted styrene - Divinylbenzene copolymers and S1O2, AI2O3, ΤΊΟ2, ZrC "2 and mixtures thereof. Electrochemical cell according to one of Claims 1 to 5, characterized in that the chemical compound contained in layer (C) is present in a homogeneous distribution in particulate form, in the form of a film or in layer (C). An electrochemical cell according to any one of claims 1 to 6, characterized in that the organic radical contained in the chemical compound is derived from an organic chelating ligand selected from the group of chelating ligands consisting of acetylacetone and its salts, salicylimide and its salts, Ν, Ν Ethylenebis (salicylimine) and its salts, ethylenediamine, 2- (2-aminoethylamino) ethanol, diethylenetriamine, iminodiacetic acid and its salts, triethylenetetramine, triaminotriethylamine, nitrilotriacetic acid and its salts, ethylenediaminotriacetic acid and its salts, ethylenediaminetetraacetic acid and its salts, diethylenetriaminepentaacetic acid and their salts, 1, 4,7,10-tetraazacyclododecane-1, 4,7,10-tetraacetic acid and its salts, oxalic acid and their salts, tartaric acid and its salts, citric acid and its salts, dimethylglyoxime, 8-hydroxyquinoline and its salts, dimercaptosuccinic acid and its salts, 2,2'-bipyridine, 1, 10-phenanthroline and substituted derivatives thereof. Electrochemical cell according to one of claims 1 to 7, characterized in that the organic radical contained in the chemical compound is derived from an organic chelating ligand in which one or more acidic protons have been replaced by lithium cations. An electrochemical cell according to any one of claims 1 to 8, characterized in that the organic radical derived from an organic chelating ligand is covalently bound to the chemical compound. 10. An electrochemical cell according to any one of claims 1 to 8, characterized in that the organic radical derived from an organic Chelatliganden is bound by absorption on the chemical compound. 1 1. Electrochemical cell according to one of claims 1 to 10, characterized in that layer (C) comprises a binder (b) selected from the group of polymers consisting of polyvinyl alcohol, styrene-butadiene rubber, polyacrylonitrile, carboxymethyl cellulose and fluorine-containing ( co) polymers. 12. An electrochemical cell according to any one of claims 1 to 1 1, characterized in that layer (C) has an average thickness in the range of 9 to 50 μηη. 13. An electrochemical cell according to any one of claims 1 to 12, characterized in that layer (C) is a separator. 14. An electrochemical cell according to any one of claims 1 to 13, characterized in that layer (C) additionally contains a fleece (c). 15. An electrochemical cell according to any one of claims 1 to 14, characterized in that layer (C) covers the cathode (A) or a separator or the anode (B) on at least one side. 16. Use of electrochemical cells according to one of claims 1 to 15 in lithium-ion batteries. 17. Lithium-ion battery, comprising at least one electrochemical cell according to one of claims 1 to 15. 18. Use of electrochemical cells according to any one of claims 1 to 15 in automobiles, powered by electric motor two-wheelers, aircraft, ships or stationary energy storage. Use of a chemical compound containing at least one organic radical derived from an organic chelating ligand for the preparation of an electrochemical cell. 20. Use of an organic or inorganic polymer containing at least one organic radical derived from an organic chelating ligand for the preparation of an electrochemical cell.