KR20140104995A - Electrochemical cells comprising nitrogen-containing polymers - Google Patents

Abstract

An electrochemical cell comprises (A) at least one cathode comprising at least one lithium ion-containing transition metal compound, (B) at least one anode, and (C) a nitrogen-containing 5- or 6- One or more polymers comprising at least one polymer comprising aromatic units or monomer units comprising alpha-aminophosphonic acid or an organic radical derived from iminodiacetic acid, and (b) optionally at least one binder. do.

Description

ELECTROCHEMICAL CELLS COMPRISING NITROGEN-CONTAINING POLYMERS CONTAINING NITROGEN-

According to the present invention,

(A) one or more cathodes comprising one or more lithium ion-containing transition metal compounds,

(B) one or more anodes, and

(C) one or more polymers comprising (a) monomer units comprising a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or an alpha -aminophosphonic acid or an organic radical derived from iminodiacetic acid, and (b) optionally one or more layers comprising at least one binder

To an electrochemical cell.

The invention further relates to the use of the electrochemical cell of the invention and to a lithium ion battery comprising one or more electrochemical cells of the invention.

Energy storage has long been of increasing interest. An electrochemical cell, such as a battery or a battery, can act to store electrical energy. Recently, a so-called Li-ion battery has attracted particular interest. They are superior to conventional batteries in some technical aspects. For example, they can be used to generate a voltage that can not be obtained by a battery based on an aqueous electrolyte.

In this regard, one important role is played by the materials that make up the electrodes, and especially the materials that make up the cathode.

In many cases, lithium-containing mixed transition metal oxides are used, especially lithium-containing nickel-cobalt-manganese oxides having a layered structure, or manganese-containing spinel which can be doped with one or more transition metals. However, many batteries still have cycling stability issues, which still need to be improved. Specifically, in the case of these batteries containing a relatively high proportion of manganese, for example an electrochemical cell with a manganese-containing spinel electrode and a graphite anode, a serious loss of capacity is often observed in a relatively short time. Further, when the graphite anode is selected as the counter electrode, deposition of elemental manganese on the anode can be detected. These manganese nuclei deposited on the anode are believed to act as a catalyst for the reductive decomposition of the electrolyte at a potential of less than 1 V relative to Li / Li ^{< + &} gt ;. It is also believed that this is involved in the irreversible binding of lithium, and as a result, lithium ion batteries gradually lose capacity.

International Patent Application Publication No. WO 2009/033627 discloses one ply which can be used as a separator plate for a lithium ion battery. This includes nonwoven, and particles that are inserted into the nonwoven and composed of an organic polymer and possibly a partially inorganic material. Such a separator can prevent a short circuit caused by a metal dendrite. However, International Patent Application Publication No. WO 2009/033627 does not disclose long-term cycling experiments at all.

International Patent Application Publication No. WO 2011/024149 discloses a lithium ion battery comprising an alkali metal, such as lithium, acting between the cathode and the anode, which acts as a scavenging agent for unwanted byproducts or impurities. In both the manufacturing process of the secondary battery cell and the subsequent recycling process of the spent battery, appropriate safety precautions must be taken due to the presence of highly reactive alkali metals.

It is therefore an object of the present invention to provide a process for the preparation of a lithium secondary battery which has an improved life span and which does not exhibit deposition of elemental manganese even after several cycles or during the manufacturing process has a lower level of safety problems than alkaline metals, And to provide an electric battery which can use a scavenger.

This purpose

(A) one or more cathodes comprising one or more lithium ion-containing transition metal compounds,

(B) one or more anodes, and

(C) one or more polymers comprising (a) monomer units comprising a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or an alpha -aminophosphonic acid or an organic radical derived from iminodiacetic acid, and (b) optionally at least one layer comprising at least one binder.

Cathode (A) includes one or more lithium ion-containing transition metal compounds, such as transition metal compounds LiCoO ₂ , LiFePO _4, or lithium-manganese spinel, as known to those skilled in the art of lithium ion battery technology. The cathode (A) preferably contains, as a lithium ion-containing transition metal compound, a lithium ion-containing transition metal oxide (including manganese as a transition metal).

The lithium ion-containing transition metal oxide containing manganese as the transition metal means an oxide having at least one transition metal in cationic form as well as an oxide having at least two transition metal oxides in cationic form in the context of the present invention I understand. Further, in the context of the present invention, the term "lithium ion-containing transition metal oxide" also includes lithium, as well as those compounds comprising at least one non-transition metal in the cationic form, such as aluminum or calcium .

In one preferred embodiment, manganese can be generated in the formal oxidation state of +4 in the cathode (A). The manganese in the cathode (A) more preferably occurs in the formal oxidation state in the range of +3.5 to +4.

Many elements are everywhere. For example, sodium, potassium and chloride are actually detectable in very small proportions specific to all inorganic substances. In the context of the present invention, less than 0.1% by weight of cations or anions are ignored. Any lithium ion-containing mixed transition metal oxide containing less than 0.1% by weight sodium is therefore considered to be sodium-free in the context of the present invention. Correspondingly, any lithium ion-containing mixed transition metal oxide containing less than 0.1% by weight of sulfate ions is considered to be a sulfate-free in the context of the present invention.

In one embodiment of the present invention, the lithium ion-containing transition metal oxide is a mixed transition metal oxide comprising manganese as well as at least one additional transition metal.

In one embodiment of the present invention, the lithium ion-containing transition metal compound is selected from manganese-containing lithium iron phosphate, preferably a manganese-containing spinel and a manganese-containing transition metal oxide having a layer structure, ≪ / RTI > is selected from manganese-containing mixed transition metal oxides.

In one embodiment of the present invention, the lithium ion-containing transition metal compound is selected from these compounds having lithium in superstoichiometric proportions.

In one embodiment of the present invention, the manganese-containing spinel is selected from a compound of the formula:

In the above equation, the variables are respectively defined as follows:

0.9? A? 1.3, preferably 0.95? A? 1.15,

0? B? 0.6, for example 0.0 or 0.5, where

When the selected M &^lt; ^{1 >} = Ni, preferably 0.4 ≤ b &

-0.1? D? 0.4, preferably 0? D? 0.1.

M ¹ is selected from Al, Mg, Ca, Na, B, Mo, W and at least one element selected from transition metals in the first period of the periodic table of the elements. M ¹ is preferably selected from Ni, Co, Cr, Zn and Al, and M ¹ is most preferably Ni.

In one embodiment of the present invention, the manganese-containing spinel is selected from the compounds of the formulas LiNi _0.5 Mn _1.5 O _4-d and LiMn ₂ O ₄ .

In another embodiment of the present invention, the manganese-containing transition metal oxide having a layer structure is selected from the following compounds:

In the above equation, the variables are respectively defined as follows:

0? T? 0.3,

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

In one embodiment of the invention, at least 30 mole%, based on the total amount of M ² M ² it is selected from manganese, preferably 35 mol%.

In one embodiment of the present invention, M ² is selected from a combination of Ni, Co and Mn, which does not contain any additional elements in significant amounts.

In another embodiment, M ² is selected from a combination of Ni, Co, and Mn, which comprises significant amounts of one or more additional elements and is, for example, Al, Ca, or Na in the range of 1 to 10 mole percent .

In one embodiment of the present invention, the manganese-containing transition metal oxide having a layer structure is one in which M ² is Ni _0.33 Co _0.33 Mn _0.33 , Ni _0.5 Co _0.2 Mn _0.3 , Ni _0.4 Co _0.3 Mn _0.4 , Ni _0.4 Co _0.2 Mn _0.4 And Ni _0.45 Co _0.10 Mn _0.45 .

In one embodiment, the lithium-containing transition metal oxide is in the form of primary particles agglomerated in spherical secondary particles, wherein the primary particles have an average particle diameter (D50) in the range of 50 nm to 2 占 퐉, Has an average particle diameter (D50) in the range of 2 占 퐉 to 50 占 퐉.

The cathode (A) may comprise one or more additional components. For example, the cathode (A) may comprise carbon as a conductive polymorph, and may include, for example, graphite, carbon black, carbon nanotube, graphene, It is selected from mixtures of two or more. In addition, the cathode (A) may comprise one or more binders, for example one or more organic polymers. Suitable binders are, for example, organic (co) polymers. Suitable (co) polymers, i. E. Homopolymers or copolymers, can be prepared from (co) polymers obtainable, for example, by anionic, catalytic or free radical (co) polymerizations, in particular from polyethylene, polyacrylonitrile, , Polystyrene, and copolymers of two or more comonomers selected from ethylene, propylene, styrene, (meth) acrylonitrile and 1,3-butadiene, and particularly styrene-butadiene copolymers. Polypropylene is also suitable. Polyisoprene and polyacrylates are additionally suitable. Polyacrylonitrile is particularly preferred.

Polyacrylonitrile is understood to mean a polyacrylonitrile homopolymer in the context of the present invention, as well as copolymers of acrylonitrile and 1,3-butadiene or styrene. Polyacrylonitrile homopolymers are preferred.

In the context of the present invention, polyethylene is a homopolymer of polyethylene, as well as at least 50 mol% of ethylene in copolymerized form and at most 50 mol% of one or more further comonomers such as alpha-olefins such as propylene, butylene Butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene and also isobutene, vinyl aromatic such as styrene and also (meth) acrylic acid, vinyl acetate, vinyl prop C ₁ -C ₁₀ -alkyl esters of (meth) acrylic acid, especially methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n -Butyl methacrylate, 2-ethylhexyl methacrylate, and also ethylene, including maleic acid, maleic anhydride and itaconic anhydride. The polyethylene may be HDPE or LDPE.

In the context of the present invention, the polypropylene is a homopolypropylene, as well as at least 50 mole% propylene in copolymerized form, and at most 50 mole% of one or more additional comonomers such as ethylene and alpha-olefins such as butyl Is understood to mean a copolymer of propylene, including butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 1-pentene. The polypropylene is preferably an isotactic or essentially the same arrangement of polypropylene.

In the context of the present invention, polystyrene is a homopolymer of styrene, as well as acrylonitrile, 1,3-butadiene, (meth) acrylic acid, C ₁ -C ₁₀ -alkyl esters of (meth) acrylic acid, divinylbenzene, , 3-divinylbenzene, 1,2-diphenylethylene and? -Methylstyrene.

Another preferred binder is polybutadiene.

Other suitable binders are selected from polyethylene oxide (PEO), cellulose, carboxymethylcellulose, polyimide, and polyvinyl alcohol.

In one embodiment of the present invention, the binder is selected from these (co) polymers having an average molecular weight M _w ranging from 50,000 to 1,000,000 g / mole, preferably up to 500,000 g / mole.

The binder may be a crosslinked or non-crosslinked (co) polymer.

In a particularly preferred embodiment of the present invention, the binder is selected from halogenated (co) polymers, especially fluorinated (co) polymers. The halogenated or fluorinated (co) polymer is a copolymer of at least one (co) monomer having at least one halogen atom or at least one fluorine atom per molecule, preferably at least two halogen atoms per molecule or at least two fluorine atoms (Co) polymer in the form of a copolymerized form.

Examples are polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer ( PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymer, perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer and ethylene- Chlorofluoroethylene copolymer.

Suitable binders are, in particular, polyvinyl alcohols and halogenated (co) polymers such as polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co) polymers such as polyvinyl fluoride and especially polyvinylidene fluoride and poly Tetrafluoroethylene.

In addition, the cathode A can furthermore be placed on its own in the form of customary constituents, for example metal wires, metal grids, metal bodies, expanded metal, metal sheets or metal foils Gt; output conductor < / RTI > Suitable metal foils are, in particular, aluminum foil.

In one embodiment of the present invention, the cathode A has a thickness in the range of 25 to 200 mu m, preferably 30 to 100 mu m, based on the thickness without output conductors.

The electrochemical cell of the present invention further comprises at least one anode (B).

In one embodiment of the present invention, the anode (B) can be selected from an anode comprising carbon and an anode comprising Sn or Si. The anode composed of carbon may be selected from, for example, light carbon, soft carbon, graphene, graphite, and in particular, graphite, intercalated graphite and a mixture of two or more of the above-mentioned carbon. The anode containing Sn or Si may be selected from, for example, nanoporous Si or Sn powder, Si or Sn fiber, carbon-Si or carbon-Sn composite material, and Si-metal or Sn-metal alloy .

The anode (B) may have one or more binders. The selected binder may be one or more of the binders described above in connection with the description of the cathode (A).

Further, the anode B may further have an output conductor, which itself can be arranged in the form of conventional components such as metal wires, metal grids, metal bodies, expanded metal, or metal foils or metal sheets . Suitable metal foils are, in particular, copper foils.

In one embodiment of the present invention, the cathode (B) has a thickness in the range of 15 to 200 mu m, preferably 30 to 100 mu m, based on the thickness without output conductors,

The electrochemical cell of the present invention further comprises (C) (a) a monomer unit comprising an organic radical derived from a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or a -aminophosphonic acid or from iminodiacetic acid (Also referred to simply as polymer (a)), and (b) optionally one or more binders (also referred to simply as binder (b) (C)).

The nitrogen-containing 5- or 6-membered heterocyclic aromatic structural units are in principle known to those skilled in the art. These may be monovalent or multivalent, for example, bivalent or trivalent, monocyclic or polycyclic, substituted or unsubstituted structural units. Examples of such structural units are:

In the above formula, the atom marked with * indicates the site where the structural unit is incorporated into the polymer. As the structural unit, imidazolyl is preferable. The monovalent structural units may be bonded directly to the polymer backbone or via a divalent linking element, while the divalent structural units may be incorporated into the polymer backbone.

In one preferred embodiment of the present invention, the polymer (a) is present in the layer (C) and is derived from a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or a -aminophosphonic acid or from iminodiacetic acid Wherein the monomer units are selected from the group of monomer units comprising:

In this formula,

X is O, S or NR and R is hydrogen or a C ₁ -C ₄ alkyl radical such as methyl, ethyl, n-propyl or n-butyl.

In a particularly preferred embodiment, the monomer unit is N-vinylimidazole.

The polymer (a) present in the layer (C) contains a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or a monomeric unit comprising an organic radical derived from? -Aminophosphonic acid or from iminodiacetic acid In each case only one containing homopolymer. Further, the polymer (a) present in the layer (C) contains a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or an organic radical derived from? -Aminophosphonic acid or an iminodiacetic acid But may also be copolymers comprising at least one additional monomer unit. The additional monomer units of the copolymer may in principle be any known monomer units copolymerizable with the former monomer units.

The polymer (a) present in the layer (C) contains a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or a monomeric unit comprising an organic radical derived from? -Aminophosphonic acid or from iminodiacetic acid , More preferably at least 20 wt%, even more preferably at least 40 wt%, especially at least 50 wt%, based on the total mass of polymer (a) % ≪ / RTI >

In one preferred embodiment of the invention, the polymer (a) present in layer (C) is a copolymer comprising N-vinylimidazole and N-vinyl-2-pyrrolidone monomer units. N-vinylimidazole and N-vinyl-2-pyrrolidinone are known. For example, crosslinked copolymers comprising N-vinylimidazole and N-vinyl-2-pyrrolidinone are commercially available as Divergan (R) HM from BASF, It is insoluble in solvents. However, solutions of copolymers containing N-vinyl-2-pyrrolidinone and N-vinylimidazole are also commercially available, for example Sokalan (R) HP 56 K from BASF or SOCALAN (R) HP 66K.

Depending on the nature of the polymer (a) as present in layer (C) and discussed above, such polymers may be present in different forms in layer (C). Insoluble polymers such as Divergan (R) from BASF, a cross-linked copolymer, are preferably incorporated into the layer (C) in the form of particles, while the corresponding soluble polymer is processed into a film, , For example, on or within a carrier material, which may be of organic or inorganic origin. For example, the separator described in International Patent Application Publication No. WO 2009/033627, or its components, can be prepared by reacting an N-vinyl-2 For example, a solution of a solution of a copolymer comprising pyrrolidinone and N-vinylimidazole, for example Soca (R) HP 66 K or Luvitec (R) VPI 55 K 72 W, For example, impregnated or sprayed. It is also possible to use the polymer (a) in particulate form with the inorganic or organic particles used in WO 2009/033627 to prepare a correspondingly modified nonwoven. Also, by grafting techniques, for example, grafting of vinylimidazole onto an aromatic polyether ketone phase or copolymerization of a copolymer of N-vinyl-2-pyrrolidinone and N-vinylimidazole with polyethylene glycol In order to achieve a novel polymer (a) by grafting a monomer unit comprising a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or an? -Aminophosphonic acid or an organic radical derived from iminodiacetic acid Or to chemically bond the first polymer (a) to the further polymer.

In one embodiment of the invention, in the electrochemical cell of the present invention, the polymer present in layer (C) is in particulate form, film form, or evenly distributed in layer (C). Preferably, the polymer present in layer (C) is in particulate form. The particulate polymer has an average particle diameter (D50) in the range of 0.05 to 100 mu m, preferably 0.5 to 10 mu m, more preferably 2 to 6 mu m in the context of the present invention.

The weight ratio of the polymer (a) in the total mass of the layer (C) may be 100% by weight or less. Preferably, the weight ratio of polymer (a) in the total mass of layer (C) is 5% by weight or more, more preferably 40 to 80% by weight; The weight ratio of the polymer (a) in the total mass of the layer (C) is in particular in the range of 30 to 50% by weight.

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

In one preferred embodiment of the present invention, layer (C) is selected from the group of polymers consisting of polyvinyl alcohol, styrene-butadiene rubber, polyacrylonitrile, carboxymethylcellulose and fluorinated (co) (B) selected from butadiene rubber and fluorinated (co) polymers.

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

In yet another embodiment, the binder (b) is different from the binder for the cathode (A) and / or the binder for the anode (B), or the binder for the anode (B) .

In one embodiment of the present invention, layer (C) has an average thickness in the range of 0.1 μm to 250 μm, preferably 1 μm to 100 μm, and more preferably 5 μm to 30 μm.

Layer C is preferably a layer that does not conduct current, i.e., an electrical insulator. Secondly, layer C is preferably a layer that allows migration of ions, especially Li < * > ions. Preferably, layer (C) is spatially arranged between the cathode and the anode in the electrochemical cell of the present invention.

In an electrochemical cell, direct contact between the anode and the cathode, which results in a short circuit, is typically prevented by incorporation of a separator plate.

In a further aspect of the invention, in the electrochemical cell of the invention, layer (C) is a separator.

The layer (C) comprises not only the polymer (a) and the optional binder (b) but also the constituents which ensure the improved stability of the layer (C) without compromising the requisite porosity and ion permeability thereof, Such as fibers or nonwoven fabrics. Alternatively, or additionally, layer (C) may also comprise at least one porous polymer layer, for example a polyolefin membrane, in particular a polyethylene or polypropylene membrane. The polyolefin membrane may be formed from one or more layers in reverse. The porous polyolefin membrane or the nonwoven itself may generally fulfill the function of the separator itself. Layer (C) is naturally inorganic or organic and may comprise, for example, particles embodied in International Patent Application Publication No. WO 2009/033627.

In one embodiment of the present invention, in the electrochemical cell of the present invention, layer (C) further comprises a nonwoven (c).

The nonwoven (c) can be made from 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 Fabric and PTFE nonwoven fabric.

Examples of inorganic nonwoven fabrics are glass fiber nonwoven fabrics and ceramic fiber nonwoven fabrics.

Depending on the composition of the layer (C), it may, for example, consist solely of the polymer (a), for example of a porous film of the polymer (a), or of the polymer (a) Or a polyester nonwoven fabric in which the particles of the polymer (a) are uniformly distributed therein. In these cases, layer C may itself be already used as a separator in the electrochemical cell of the present invention, thus covering cathode (A) or anode (B) on one or more sides. The layer (C) may also be applied to a conventionally available battery separator plate, such as a porous polyolefin membrane or nonwoven, so that the layer (C) covers the separator plate on one or more sides. Layer C may also be applied as a thin layer to a cathode or anode, and the electrochemical cell of the present invention produced thereby may additionally include a porous polyolefin membrane as a separator.

In a further embodiment of the present invention, the electrochemical cell layer (C) of the present invention covers the cathode (A) or separator plate or anode (B) on one or more sides.

The present invention further relates to a process for the preparation of an electrochemical cell, in particular an electrochemical cell of the invention as described above, which comprises reacting a 5- or 6-membered heterocyclic aromatic structural unit or a-aminophosphonic acid or from iminodiacetic acid (A) as described above, comprising a monomer unit comprising an organic radical which has been removed.

The layer (C) present in the electrochemical cell of the present invention, depending on its structure, is produced as a semi-finished product irrespective of the assembly portion of the electrochemical cell of the present invention, For example, as a finished separator plate, or with a typical battery separator plate, such as a PET nonwoven fabric or a porous polyolefin film, in an electrochemical cell by a battery manufacturer.

The electrochemical cell of the present invention may also have conventional components, such as conductive salts, non-aqueous solvents, and also cable connections and housings.

In one embodiment of the invention, the electrochemical cell of the present invention can be liquid or solid at room temperature, preferably liquid at room temperature, and is preferably a polymer, a cyclic or acyclic ether, a cyclic or acyclic acetal, And at least one non-aqueous solvent selected from cyclic or acyclic organic carbonates and ionic liquids.

Examples of suitable polymers are in particular polyalkylene glycols, preferably poly-C ₁ -C ₄ -alkylene glycols and in particular polyethylene glycols. Polyethylene glycol may contain up to 20 mole% of one or more C ₁ -C ₄ -alkylene glycols in copolymerized form. The polyalkylene glycols are preferably di-methyl- or -ethyl-end-capped polyalkylene glycols.

Suitable polyalkylene glycols, and particularly suitable polyethylene glycols, may have a molecular weight M _w of at least 400 g / mole.

Suitable polyalkylene glycols, and particularly suitable polyethylene glycols, have a molecular weight M _w of 5,000,000 g / mol or less, preferably 2,000,000 g / mol or less.

Examples of suitable acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1,2-dimethoxyethane and 1,2-diethoxyethane, with 1,2-dimethoxyethane being preferred Do.

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

Examples of suitable acyclic 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 acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.

Examples of suitable cyclic organic carbonates are compounds of the formulas:

Wherein R ¹ , R ² and R ³ are the same or different and are each hydrogen and C ₁ -C ₄ -alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, Butyl and tert-butyl, wherein R ² and R ³ are preferably not both tert-butyl.

In a particularly preferred embodiment, 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 of formula 5:

It is preferred to use a solvent (s) which is referred to as anhydrous, i.e. has a water content in the range of 1 ppm to 0.1% by weight, which is measurable by Karl Fischer titration, for example.

The electrochemical cell of the present invention further comprises at least one conductive salt. Suitable conductive salts are, in particular, lithium salts. For suitable lithium salts include _{LiPF 6, LiBF 4, LiClO 4} , LiAsF 6, LiCF 3 SO 3, LiC (C n F 2n + 1 SO 2) 3, Li imide, such as _{LiN (C n F 2n + 1} SO 2 ) ₂ (where n is from 1 to an integer of 20 _{range), LiN (SO 2 F)} 2, Li 2 SiF 6, LiSbF 6, LiAlCl 4 and formula (C _n F _{2n + 1} SO ₂ salts) _m XLi, Where m is defined as:

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

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

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

Preferred conducting salts are _{LiC (CF 3 SO 2) 3} , LiN (CF 3 SO 2) 2, LiPF 6, LiBF 4, and is selected from LiClO _4, LiPF ₆ and LiN (CF ₃ SO ₂₎ is ₂ are particularly preferred .

The electrochemical cell of the present invention further comprises a housing which may be in any form, for example a rectangular parallelepiped or cylinder. In another embodiment, the electrochemical cell of the invention has the form of a prism. In one variant, the housing used is a metal-plastic composite film processed as a pouch.

The electrochemical cell of the present invention provides a high voltage of approximately 4.8 volts or less and is remarkable for high energy density and good stability. More particularly, it is noteworthy that the electrochemical cell of the present invention has very little capacity loss during repeated cycling.

The present invention further provides the use of the electrochemical cell of the present invention in a lithium ion battery. The present invention further provides a lithium ion battery comprising one or more electrochemical cells of the present invention. The electrochemical cell of the present invention can be combined with each other in the lithium ion battery of the present invention, for example, in series connection or parallel connection. A series connection is preferred.

The invention further provides the use of an electrochemical cell of the invention as described above in a motor vehicle, an electric motorized bicycle, an airplane, a vessel, or a non-mobile energy storage.

The present invention therefore further provides the use of the lithium ion battery of the present invention in a device, particularly a mobile device. Examples of mobile devices are vehicles, such as cars, bicycles, airplanes, or watercraft vehicles, such as boats or ships. Other examples of mobile devices include portable devices such as computers, especially laptops, telephones or power tools, such as tools from the field of construction, particularly drills, battery-powered screwdrivers or battery- to be.

The use of the lithium ion battery of the present invention in the device provides the advantage of extended running time prior to recharging and less loss of capacity during extended run time. If the present invention had been to achieve the same running time by an electrochemical cell with a lower energy density, a higher weight for the electrochemical cell would have to be allowed.

1 shows a schematic structure of a disassembled electrochemical cell for testing a separator of the present invention and a separator other than the present invention.
* A brief description of the designator
In Figure 1, the annotation means:
1, 1 'die
2, 2 'nut
3, 3 'sealing rings - 2 in each case; The second, in each case somewhat smaller, sealing ring is not shown in the figure.
4 spiral spring
5 Nickel output conductor
6 Housing

The invention is illustrated by the following examples which do not limit the invention.

The values expressed in% are based on% by weight unless otherwise explicitly stated.

I.1 Preparation of the separator plate (S.1) of the present invention

A crosslinked copolymer (Divergan TM HM from BASF) of a 10:90 ratio of vinylpyrrolidone (VP) and N-vinylimidazole (VI) was placed in an AFG fluidized bed counter-jet mill counter -jet mill to a particle size of less than 8 占 퐉 (占 10 = 1.2 占 퐉, 占 50 = 4.7 占 퐉, 占 90 = 7.9 占 퐉). The particle size distribution was determined in powder form by Mastersizer from Malvern Instruments GmbH, Herrenberg, Germany using laser diffraction techniques. A 13 mm diameter disc was punched from a glass fiber nonwoven fabric (Whatman, 260 [mu] m thickness) and dried in a drying oven at 120 [deg.] C for several hours. The glass fiber nonwoven fabric disc was then transferred to an argon-filled glovebox. Each glass fiber nonwoven fabric disc was divided into two parts so that one glass fiber nonwoven fabric disc 260 [mu] m thick provided two glass fiber nonwoven fabric discs each approximately 130 [mu] m thick. The cross-linked copolymers (90:10) (Divergan (TM) HM) of the previously milled VI and VP were uniformly distributed over the entire area between two glass fiber disks, for example, about 5 A glass fiber nonwoven fabric / Divergan TM HM / glass fiber nonwoven fabric sandwich with a relative surface coverage of 10 mg / cm2 of Divergan (R) HM was formed.

I.2 Preparation of the separator (S.2) of the present invention

An aqueous solution of a non-crosslinked copolymer of a 45:55 ratio of vinylpyrrolidone and N-vinylimidazole (Rubitech (TM) VPI 55 K 72 W from BASF) was evaporated in a drying oven overnight at 40 ° C Lt; / RTI > The residue was roughly ground in a mortar and a bowl and then dried in a vacuum desiccator for 2 days on P ₂ O ₅ . The dried residue was finely milled by an agate mortar under an argon protective gas until the particle size was less than about 20 [mu] m. A disc of 13 mm diameter was punched out of glass fiber nonwoven fabric (watt only, 260 탆 thickness) and dried in a drying oven at 120 캜 for several hours. The glass fiber nonwoven fabric disc was then transferred to an argon-filled glove box. Each glass fiber nonwoven fabric disc was divided into two parts so that one glass fiber nonwoven fabric disc 260 [mu] m thick provided two glass fiber nonwoven fabric discs each approximately 130 [mu] m thick. The previously milled RubiTec TM VPI 55 K 72 W is uniformly distributed between the two glass fiber disks over the entire area, for example, approximately 5 to 10 mg / cm 2 of Rubitec VPI A glass fiber nonwoven fabric / Rubitech (R) VPI 55 K 72 W / glass fiber nonwoven fabric sandwich with a relative surface coverage of 55 K 72 W was formed.

I.3 Preparation of the separator plate (S.3) of the present invention

1.9 g of Fine Divergan (TM) HM prepared from Example I.1 above was mixed with 0.2 g of styrene-butadiene rubber (average particle size: 190 nm; glass transition temperature: -10 캜; binder 20-01) Of a 50% by weight aqueous emulsion and 8 ml of water to give a stirrable suspension and stirring for approximately 1 hour. The suspension thus obtained was uniformly knife-coated as a "PES20" nonwoven from APODIS Filtertechnik OHG onto a commercially available PET nonwoven fabric and the coated nonwoven fabric was dried overnight at room temperature. After drying, a nonwoven having a Divergan (TM) HM coverage of approximately 5 to 10 mg / cm 2 in each case was obtained. The disc was then punched out and dried again in a vacuum drying oven at 120 占 폚 for 16 hours. Subsequently, these disks were transferred to an argon-filled glove box.

I.4 Preparation of separator (C-S.4) other than the present invention

Except that it was not filled with Divergan TM HM or Rubietech VPI 55 K 72 W to obtain a comparative separator CS.4 but instead used in an uncharged state instead The experiment from Example I.1 or I.2 was similarly repeated under the same conditions.

I.5 Preparation of separator (C-S.5) other than the present invention

To obtain a comparative separator CS.5, the experiment from Example I.3 was repeated except that the PET sub-fabric was not coated with Divergan (TM) HM and instead used in an uncharged state. Lt; / RTI >

II. Manufacturing and testing of electrochemical cells

The following electrode was always used:

Cathode (A.1): A lithium-nickel-manganese spinel electrode was used in each case, which was prepared as follows. The following components were mixed together in a screw-top container:

85% LiMn _1.5 Ni _0.5 O ₄

6% PVdF commercially available as Kynar Flex (TM) 2801 from the Arkema Group,

6% carbon black (BET surface area 62 m ² / g) commercially available as "Super P Li " from Timcal,

3% graphite commercially available as KS6 from Timal.

During stirring, a sufficient amount of N-methylpyrrolidone was added to obtain a lumpless viscous paste. The mixture was stirred for 16 hours.

The paste thus obtained was then knife-coated onto a 20 μm-thick aluminum foil and dried in a vacuum drying oven at 120 ° C. for 16 hours. The thickness of the coating after drying was 30 탆. Subsequently, round disk-shaped compartments of 12 mm diameter were punched out.

Anode (B.1): The following components were mixed together in a screw-top container:

91% graphite, ConocoPhillips C5,

6% PVdF commercially available as Kainarplex (TM) 2801 from the Arkema group,

3% Carbon Black (BET surface area 62 m ² / g) commercially available as "Super P Li" from Tim Carl. During stirring, a sufficient amount of N-methylpyrrolidone was added to obtain a lumpless viscous paste. The mixture was stirred for 16 hours.

The paste thus obtained was then knife-coated onto a 20 μm-thick copper foil and dried in a vacuum drying oven at 120 ° C. for 16 hours. The thickness of the coating after drying was 35 탆. Subsequently, round disk-shaped compartments of 12 mm diameter were punched out.

The following electrolytes were always used:

A 1 M solution of LiPF _{6 in} an anhydrous ethylene carbonate-ethylmethyl carbonate mixture (1: 1 weight ratio)

II.1 Preparation and testing of the electrochemical cell EC.1 of the present invention

In an argon-filled glove box, the electrolyte was dropped onto the inventive separator (S.1) prepared according to I.1 and placed between the cathode (A.1) and the anode (B.1) Both the anode and the cathode were brought into direct contact with the separator plate. This provides the electrochemical cell EC.1 of the present invention. The electrochemical analysis was performed at a voltage of 4.25 V to 4.8 V in a Swagelok cell.

The first two cycles run at a speed of 0.2 C for formation; The third to fifty cycles were circulated at a speed of 1 C, and then the two cycles were run at a speed of 0.2 C, and then the 48 cycles were run at a speed of 1 C or the like. Charging and discharging of the battery was performed at room temperature with the help of a "MACCOR battery tester ". It has been found that battery capacity remains very stable over the course of repeated charging and discharging.

II.2 to II.5 Manufacture and test of electrochemical cells EC.2, EC.3, and C-EC.4, C-EC.5

Similar to Example II.1, electrochemical cells EC.2, EC.3, and C-EC.4 and C-EC.4 using separators S.2, S.3, and CS.4 and CS.5, EC.5 were prepared and tested correspondingly.

result:

The electrochemical cell EC.1 was charged and discharged in a very stable manner for 160 cycles and only 27% of the starting capacity was lost after 130 cycles.

Electrochemical cell EC.2 was charged and discharged in a very stable manner for 160 cycles and only 11% of the starting capacity after 130 cycles was lost.

The electrochemical cell EC.2 was charged and discharged in a very stable manner for 160 cycles and only 14% of the starting capacity after 130 cycles was lost.

The electrochemical cell C-EC.4 from the comparative example was relatively much degraded in performance, and after about 130 cycles, 46% of the starting capacity was lost.

The electrochemical cell C-EC.5 from the comparative example was relatively much degraded in performance and similarly, about 46% of the starting capacity was lost after about 130 cycles.

Claims (15)

(A) one or more cathodes comprising one or more lithium ion-containing transition metal compounds,
(B) one or more anodes, and
(C) one or more polymers comprising (a) monomer units comprising a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or an alpha -aminophosphonic acid or an organic radical derived from iminodiacetic acid, and (b) optionally one or more layers comprising at least one binder
And an electrochemical cell. The method according to claim 1,
Wherein the lithium ion-containing transition metal compound is selected from manganese-containing spinel and manganese-containing transition metal oxide having a layer structure. 3. The method according to claim 1 or 2,
Wherein the anode (B) is selected from an anode comprising carbon and an anode comprising Sn or Si. 4. The method according to any one of claims 1 to 3,
An electrochemical cell, wherein the polymer present in layer (C) comprises monomer units selected from the group consisting of:

Wherein X is O, S or NR and R is hydrogen or a C ₁ -C ₄ alkyl radical. 4. The method according to any one of claims 1 to 3,
Wherein the polymer present in layer (C) is a copolymer comprising N-vinylimidazole and N-vinyl-2-pyrrolidone monomer units. 6. The method according to any one of claims 1 to 5,
Wherein the polymer present in layer (C) is in particulate form or film form, or is evenly distributed in layer (C). 7. The method according to any one of claims 1 to 6,
Wherein the layer (C) comprises a binder (b) selected from the group of polymers consisting of polyvinyl alcohol, styrene-butadiene rubber, polyacrylonitrile, carboxymethyl cellulose and a fluorinated (co) polymer. 8. The method according to any one of claims 1 to 7,
Layer (C) has an average thickness in the range of 9 to 50 [mu] m. 9. The method according to any one of claims 1 to 8,
Wherein the layer (C) is a separator. 10. The method according to any one of claims 1 to 9,
Wherein the layer (C) further comprises a nonwoven (c). 11. The method according to any one of claims 1 to 10,
Wherein the layer (C) covers the cathode (A) or the separator plate or the anode (B) on at least one side. Use of an electrochemical cell according to any one of claims 1 to 11 in a lithium ion battery. A lithium ion battery comprising at least one electrochemical cell according to any one of claims 1-11. 11. Use of an electrochemical cell according to any one of claims 1 to 11 in a motor vehicle, an electric motor-operated bicycle, an airplane, a vessel, or a non-mobile energy storage. A use for producing an electrochemical cell of a polymer comprising a monomer unit comprising a nitrogen-containing 5- or 6-membered heterocyclic aromatic structural unit or an alpha -aminophosphonic acid or an organic radical derived from iminodiacetic acid.

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