TW201304261A - Electrode materials for electrical cells - Google Patents

Abstract

The present invention relates to electrode materials for electrical cells, comprising, as component (A), at least one polymer comprising polymer chains which are formed from identical or different monomer units selected from the group consisting of substituted and unsubstituted vinyl units and substituted and unsubstituted C2-C10-alkylene glycol units and comprise at least one monomer unit -M1- which comprises at least one thiolate group -S- or at least one end of a disulfide or polysulfide bridge -(S)m- in which m is an integer from 2 to 8, the thiolate group or the one end of the disulfide or polysulfide bridge -(S)m- in each case being bonded directly to a carbon atom of the monomer unit -M1-, and, as component (B), carbon in a polymorph comprising at least 60% sp2-hybridized carbon atoms. The present invention further relates to electrical cells comprising the inventive electrode material, to specific polymers, to processes for preparation thereof and to the use of the inventive cells.

Description

Electrode material for battery

The present invention relates to an electrode material for a battery comprising at least one polymer as component (A), the at least one polymer comprising a vinyl unit selected from substituted and unsubstituted, and substituted and unsubstituted a polymer chain of the same or different monomer units of the group consisting of C ₂ -C ₁₀ alkanediol units and comprising at least one monomer unit -M1-, the monomer unit -M1- comprising at least one thiol group - S ^- or a sulfur bridge or a disulfide bridge - (S) _m - of at least one end, wherein m is an integer of 2-8, the thiolate or a disulphide bridge or the sulfur bridge - (S) _m - one end of In each case, carbon atoms directly bonded to the monomer unit -M1; and carbon in the form of a polymorph containing at least 60% of the sp ² mixed carbon atoms are used as the component (B). The invention further relates to a battery comprising the electrode material of the invention, a specific polymer, a process for its preparation and the use of the battery of the invention.

Secondary battery packs or rechargeable battery packs are just some embodiments from which electrical energy can be stored and used when needed. Due to the significantly better power density, there has been a shift from a water-based secondary battery pack to a battery pack that realizes charge transport in a battery by lithium ions.

However, conventional lithium ion batteries having a carbon anode and a metal oxide based cathode have a limited energy density. Lithium-sulfur batteries have demonstrated new prospects for energy density. Lithium - sulfur battery, the sulfur reduction of the sulfur cathode through the polysulfide ions into S ^2-, S ^2- reoxidation when the battery is charged, to form sulfur - sulfur bonds.

However, the problem is the solubility of polysulfides such as Li ₂ S ₄ and Li ₂ S ₆ which are soluble in the solvent and can migrate to the anode. Consequences can include: loss of capacitance and deposition of electrically insulating material on the electrodes. The migration of polysulfide ions from the cathode to the anode can ultimately cause the affected battery to discharge and cause the battery in the battery pack to die. This improper polysulfide ion migration is also referred to as "shuttle" and the term is also used in the context of the present invention.

Many attempts have been made to suppress this shuttle. For example, J. Wang et al. propose to add a reaction product of sulfur and polyacrylonitrile to the cathode; Adv. Funct. Mater. 2003, 13, 487 and thereafter. This process produces a product by eliminating hydrogen from polyacrylonitrile while forming hydrogen sulfide.

It has also been proposed to use sulfides instead of sulfur, such as CuS, FeS ₂ or 2,5-dimercapto-1,3,4-thiadiazole. However, the capacitance of such batteries is not satisfactory; see, for example, P. Wang, J. Electrochem. Soc. 2002, A1171-1174, 149 and J. Wang et al., J. Power Sources 2004, 138, 271.

It has also been proposed to replace pure sulfur with a polymer comprising a disulfide bridge. For example, Liu describes the use of polyorganodisulfides as materials for solid redox polymerization electrodes (M. Liu et al, J. Electrochem. Soc., 1991, 138, 1896-1901, US 5, 162, 175). This electrode is used with a polyelectrolyte for a rechargeable battery. However, a high temperature of 80 ° C to 130 ° C is required to operate the battery, and the specific capacitance achieved is extremely low.

Modification of Polymers, ACS Symposium Series, Vol. 121, 1980, 41-57 describes polymers with active chlorine groups (eg polyvinyl chloride or polyepichlorohydrin) and various nucleophiles (eg thiourea, alkali metal thiocyanate) The reaction of an acid salt or ammonium thiosulfate.

Reactive Polymers, 8, 1988, 211-220 describes the first manufacture of a resin by crosslinking a low molecular weight polyepichlorohydrin having a molar mass M _w of 1500 g/mol, followed by replacement of the chlorine group in the resin with a thiol group. A resin for adsorbing mercury (II) ions is produced.

Accordingly, it is an object of the present invention to provide a cathode material that is easy to manufacture and that avoids the disadvantages known from the prior art. Another object of the present invention is to provide novel components for such cathode materials and methods for their preparation.

This object is achieved by an electrode material for a battery comprising: (A) a polymer comprising a C selected from substituted and unsubstituted vinyl units and substituted and unsubstituted C a polymer chain of the same or different monomer units of the group consisting of ₂ - C ₁₀ alkanediol units and comprising at least one monomer unit -M1 - comprising at least one thiol group -S ^- Or at least one end of a disulfide bridge or a polysulfide bridge -(S) _m - wherein m is an integer from 2 to 8, the thiol group or the disulfide bridge or the polysulfide bridge - (S) _m - one end In the case of direct bonding to the carbon atom of the monomer unit -M1-; (B) carbon in the form of a polymorph comprising at least 60% sp ² mixed carbon atoms; (C) elemental sulfur as the case exists; and (D At least one other polymer, as the case may be, acts as a binder material.

The polymer present in the electrode material of the present invention comprises the same or different monomers selected from the group consisting of substituted and unsubstituted vinyl units and substituted and unsubstituted C ₂ -C ₁₀ alkanediol units. and forming unit comprising at least one monomer unit of the polymer chain -M1-, the monomer units comprise at least one -M1- thiolate -S ^- disulfide bridges or sulfur bridge or - (S) _m - of at least one end Wherein m is an integer from 2 to 8, and the thiol group or one of the disulfide bridge or the polysulfide bridge -(S) _m - is directly bonded to the carbon atom of the monomer unit -M1 in each case. In the context of the present invention, this polymer is also referred to simply as polymer (A) or component (A). The polymer (A) preferably comprises, in an amount of more than 50% by weight, preferably more than 80% by weight, particularly more than 95% by weight, of the above-mentioned polymer chain comprising at least one monomer unit -M1-.

The polymer chain of the polymer present in the electrode material of the present invention is the same or selected from the group consisting of substituted and unsubstituted vinyl units and substituted and unsubstituted C ₂ -C ₁₀ alkanediol units Different monomer units are formed.

Where the polymer chains are formed from different monomer units, the different monomer units may be randomly distributed or incorporated into the blocks within the polymer chain, as may be appreciated by those skilled in the art by selecting monomeric units. And/or the polymerization method is carried out within certain limits. In principle, the polymer (A) can also be a mixture of two different polymers prepared separately, followed by vigorous mixing (for example by means of an extruder), and is generally referred to as a polymer blend.

The substituted or unsubstituted vinyl units in the polymer chain or the ethylenically unsaturated compounds useful for this purpose in the polymerization are common to those skilled in the art. By way of example, -CH ₂ -CHCl- units derived from vinyl chloride monomer, a vinyl or -CH ₂ -CHPh- units derived from styrene monomer.

Polymeric chains having substituted and unsubstituted C ₂ -C ₁₀ -alkylene glycol units and monomers commonly used for this purpose in the corresponding polymerization reactions are also known to those skilled in the art. For example, the ethylene glycol unit -CH ₂ -CH ₂ -O- is derived from an ethylene oxide monomer, and the butanediol unit -CH ₂ -CH ₂ -CH ₂ -CH ₂ -O- is derived from a tetrahydrofuran monomer. , substituted ethylene glycol unit -CH ₂ -CH(CH ₂ Cl)-O- derived from epichlorohydrin monomer, and substituted propylene glycol unit -CH ₂ -C(CH ₂ Cl) ₂ -CH ₂ -O- It is derived from a bis(chloromethyl)oxetane monomer.

Polymer (A) of the polymer chain comprising at least one monomer unit -M1-, which comprises at least one monomer unit -M1- thiolate -S ^- disulfide bridges or sulfur bridge or - (S) _m - of At least one end, wherein m is an integer from 2 to 8, preferably from 2 to 4, especially 2, the thiol group or the disulfide bridge or the polysulfide bridge - (S) _m - one end in each case direct bond A carbon atom bonded to the monomer unit -M1-.

Thiolate -S ^{- +} The negative charge is balanced by the preferred metal cation Met. In a preferred embodiment, Met ⁺ comprises an alkali metal cation, a half equivalent of an alkaline earth metal dication or a half equivalent of a zinc dication, more preferably Li ⁺ , Na ⁺ , 1⁄2 Mg ⁺⁺ or 1⁄2 Zn ⁺⁺ , especially Li ⁺ .

In a preferred variation, at least 60%, preferably at least 80%, more preferably at least 95% to not more than 100% of the monomer units forming the polymer chain of the polymer (A) correspond to the monomer unit -M1- .

Without further limiting the invention, the monomer units -M1- may be illustrated by the following examples, which are derived from vinyl units or C ₂ -C ₁₀ alkanediol units:

In principle, the monomer group -M1 having a thiol group can be directly polymerized into a polymer chain by polymerization of the corresponding monomer, in which case the sulfur-containing group in the corresponding monomer is preferably protected. Used in the form of a capping, the protecting group is removed after polymerization. Alternatively, in view of the fact that the corresponding polymer has a suitable leaving group, such as a halogen atom, it may be substituted by a suitable sulfur-containing nucleophile known to those skilled in the art and may be subsequently reacted to obtain a single on the polymer chain present. Body unit - M1-.

The monomer which can be converted into a polymer by a subsequent reaction of the obtained polymer in a so-called polymer-like reaction and whose halogen atom can be converted into a monomer unit -M1- is, for example:

Similar transformations of such polymers forming sulphur-containing polymers are known from the literature, Modification of Polymers, ACS Symposium Series, Vol. 121, 1980, 41-57 and Reactive Polymers, 8, 1988, 211-220.

In a preferred embodiment, the electrode material of the present invention is characterized in that the monomer unit -M1- in the polymer chain of the polymer (A) is a substituted vinyl unit of the formula (I) and/or the formula (II) : Or a substituted ethylene glycol unit of formula (III) and/or formula (IV): More preferred are substituted ethylene glycol units of formula (III) and/or formula (IV).

In one embodiment of the present invention, in the electrode material, the second end of the disulfide bridge or the polysulfide bridge -(S) _m - is a portion of another monomer unit -M1-, the other monomer unit -M1- is present in the same polymer chain as the first monomer unit -M1- or in another polymer chain of the polymer (A). When a disulfide bridge or a polysulfide bridge -(S) _m - is formed between different polymer chains, the formed is a polymer crosslinked via a disulfide bridge or a polysulfide bridge -(S) _m - Crosslinked polymers are generally insoluble, and the corresponding individual isolated polymer chains are generally soluble in a suitable solvent.

The electrode material of the present invention for a battery further comprises carbon in the form of a polymorph comprising at least 60% sp ² mixed carbon atoms, preferably 75% to 100% sp ² mixed carbon atoms. In the context of the present invention, this carbon is also referred to simply as carbon (B) or component (B) and is known per se. Carbon (B) is a conductive carbon polymorph. The carbon (B) may be selected, for example, from graphite, carbon black, carbon nanotubes, graphene or a mixture of at least two of the above.

The numbers expressed in % are based on the electrode material and all carbon (B) present in the polymer (A) (including any impurities) and represent % by weight.

In one embodiment of the invention, carbon (B) is carbon black. The carbon black may be selected, for example, from lamp black, furnace black, flame black, thermal black, acetylene black, and industrial carbon black. (industrial black). The carbon black may contain impurities such as hydrocarbons (especially aromatic hydrocarbons) or oxygen-containing compounds or oxygen-containing groups (such as OH groups). In addition, sulfur or iron-containing impurities may be present in the carbon black.

In one variation, carbon (B) is a partially oxidized carbon black.

In one embodiment of the invention, the carbon (B) comprises a carbon nanotube. Carbon nanotubes (abbreviated as CNTs), such as single-layer carbon nanotubes (SW CNTs) and preferably multilayer carbon nanotubes (MW CNTs), are known per se. The preparation process and some properties thereof are described, for example, by Chem. Ingenieur Technik 2006, 78, 94-100 by A. Jess et al.

In one embodiment of the invention, the carbon nanotubes have a diameter in the range of 0.4 nm to 50 nm, preferably 1 nm to 25 nm.

In one embodiment of the invention, the carbon nanotubes have a length in the range of 10 nm to 1 mm, preferably 100 nm to 500 nm.

The carbon nanotubes can be prepared by a method known per se. For example, a volatile carbon compound (eg, methane or carbon monoxide, acetylene, or ethylene) or a mixture of volatile carbon compounds can be decomposed in the presence of one or more reducing agents (eg, hydrogen and/or another gas, such as nitrogen) (eg, Synthetic gas). Another suitable gas mixture is a mixture of carbon monoxide and ethylene. For example, suitable decomposition temperatures are in the range of from 400 ° C to 1000 ° C, preferably from 500 ° C to 800 ° C. For example, suitable decomposition conditions are in the range of standard pressures up to 100 bar, preferably up to 10 bar.

For example, a single or multi-layer carbon nanotube can be obtained by decomposing a carbon compound in a light arc, particularly in the presence or absence of a decomposition catalyst.

In one embodiment, the volatile carbon compound is decomposed in the presence of a decomposition catalyst such as Fe, Co or preferably Ni.

In the context of the present invention, graphene is understood to mean an almost ideal or ideal two-dimensional hexagonal carbon crystal of a similar structure of a single graphite layer.

In a preferred embodiment of the invention, the carbon (B) is selected from the group consisting of graphite, graphene, activated carbon and especially carbon black.

The carbon (B) may, for example, be in the form of particles having a diameter in the range of 0.1 μm to 100 μm, preferably 2 μm to 20 μm. The particle diameter is understood to mean the average diameter of the secondary particles (determined as the volume average).

In one embodiment of the invention, the BET surface area of carbon (B) and especially carbon black is in the range of from 20 m ² /g to 1500 m ² /g, as measured according to ISO 9277.

In one embodiment of the invention, there will be at least two, for example two or three A different kind of carbon (B) mixture. Different kinds of carbon (B) may differ, for example, in particle diameter or BET surface area or degree of contamination.

In one embodiment of the invention, the selected carbon (B) is a combination of two different carbon blacks.

Further, the electrode material of the present invention for a battery optionally contains elemental sulfur as well as polymer (A) and carbon (B). Elemental sulfur (also referred to as sulfur (C) or component (C) in the context of the present invention) is known per se.

In a preferred embodiment, the electrode material of the present invention comprises sulfur (C). In a particularly preferred embodiment, in the electrode material of the present invention, the mass ratio of the polymer (A) to the elemental sulfur (C) is in the range of 1:100 to 100:1, preferably 1:10 to 10: 1, especially 1:2 to 2:1.

In one embodiment of the invention, the electrode material of the invention comprises sulfur in the range of from 20% by weight to 80% by weight, preferably from 30% by weight to 70% by weight, determined by elemental analysis, the sulfur derived from the component (A) And component (C).

In one embodiment of the invention, the electrode material of the invention comprises carbon (B) in the range of from 0.1% by weight to 40% by weight, preferably from 1% by weight to 30% by weight. This carbon can likewise be determined by elemental analysis, for example in the case where the evaluation elemental analysis must take into account that carbon is also introduced into the electrode material of the invention via polymer (A) and possibly other sources.

Further, the electrode material of the present invention for a battery optionally contains a polymer (A) and carbon (B) and at least one other polymer as a binder, which is also referred to as a binder (D) in the context of the present invention. The binder (D) is mainly used for mechanically stabilizing the electrode material of the present invention.

In one embodiment of the invention, the binder (D) is selected from the group consisting of organic (co)polymerization Compound. Examples of suitable organic (co)polymers may be halogenated or halogen free. Examples are polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyvinyl alcohol, polyethylene, polypropylene, polytetrafluoroethylene, polyacrylonitrile-methyl methacrylate copolymer, styrene - Butadiene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymer, perfluoroalkyl vinyl ether copolymerization , ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-chlorofluoroethylene copolymer, ethylene-acrylic acid copolymer neutralized at least partially by alkali metal salt or ammonia, The case is an ethylene-methacrylic acid copolymer, an ethylene-(meth)acrylate copolymer, a polyamidene and a polyisobutylene which are at least partially neutralized with an alkali metal salt or ammonia.

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 Polytetrafluoroethylene.

The average molecular weight M _{w of the} binder (D) can be selected within wide limits, and suitable examples are from 20 000 g/mol to 1 000 000 g/mol.

In one embodiment of the present invention, the electrode material of the present invention comprises, in the range of 0.1% by weight to 10% by weight, based on the total mass of the components (A), (B), (C) and (D), preferably 1 The binder is from 5% by weight to 3% by weight and more preferably from 3% by weight to 6% by weight.

The binder (D) can be incorporated into the electrode material of the present invention by various methods. For example, a soluble binder (D) such as polyvinyl alcohol can be dissolved in a suitable solvent or solvent mixture, for example water/isopropanol is suitable for polyvinyl alcohol; and suspension can be prepared with other components of the electrode material. liquid. Apply to After the substrate is suitable, the solvent or solvent mixture is removed (e.g., evaporated) to obtain an electrode composed of the electrode material of the present invention. A suitable solvent for polyvinylidene fluoride is NMP.

If it is desired to use a sparingly soluble polymer as the binder (D), such as a polytetrafluoroethylene or tetrafluoroethylene-hexafluoropropylene copolymer, the particles of the binder (D) and the suspension of other components of the electrode material are prepared. The liquid was treated as described above to obtain an electrode.

The electrode materials of the present invention are particularly useful or suitable for use in the fabrication of electrodes, and are particularly useful in the manufacture of electrodes for lithium-containing battery packs. The invention provides the use of the electrode materials of the invention as or in the manufacture of battery electrodes. The invention further provides a battery comprising at least one electrode made from at least one electrode material of the invention or made using at least one electrode material of the invention.

In one embodiment of the invention, the electrode is a cathode. In the context of the present invention, an electrode referred to as a cathode is an electrode having a reducing action upon discharge (operation).

In one embodiment of the invention, the electrode material of the present invention is treated to obtain an electrode, for example in the form of a continuous strip that can be processed by a battery pack manufacturer.

For example, the thickness of the electrode made of the electrode material of the present invention may range from 20 μm to 500 μm, preferably from 40 μm to 200 μm. It can, for example, have a rod configuration, be configured in a circular, elliptical or square cylinder, or configured in a cubic shape, or configured as a planar electrode.

In one embodiment of the present invention, the battery of the present invention comprises the electrode material of the present invention and at least one metal magnesium, metal aluminum, metal zinc, metal An electrode of sodium or a preferred metal lithium.

In another embodiment of the present invention, the above battery of the present invention comprises the electrode material of the present invention and a liquid electrolyte comprising a lithium-containing conductive salt.

In one embodiment of the present invention, the battery of the present invention comprises, in addition to the electrode material of the present invention and another electrode (especially an electrode comprising lithium metal), at least one non-aqueous solvent, which may be liquid or at room temperature. Solid and preferably liquid at room temperature, and preferably selected from the group consisting of polymers, cyclic ethers and acyclic ethers, cyclic acetals and non-cyclic acetals, cyclic organic carbonates and acyclic organic carbonates and ions Sexual liquid.

Examples of polymers suitable for the particular polyalkylene glycol, preferably polyethylene glycol C ₁ -C ₄ alkyl and in particular is polyethylene glycol. Such polyethylene glycol may comprise one or more of up to 20 mol% of copolymerized form as a C ₁ -C ₄ alkanediols. The polyalkylene glycol is preferably a polyalkylene glycol which is double-capped with a methyl group or an ethyl group.

Suitable polyalkylene glycols are particularly suitable, and a molecular weight M _w polyethylene glycol may be at least 400 g / mol.

Suitable polyalkylene glycols are particularly suitable, and polyethylene glycol molecular weight M _w of up to 5 000 000 g / mol, preferably up to 2 000 000 g / mol.

Examples of suitable acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, preferably 1,2-dimethoxy Ethylene.

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 especially 1,3-dioxe. Pentane.

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

Examples of suitable cyclic organic carbonates are the compounds of the general formula (X) and the general formula (XI): Wherein R ¹ , R ² and R ³ may be the same or different and are selected from hydrogen and C ₁ -C ₄ alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl And a second butyl group and a third butyl group, wherein R ² and R ^{3 are} preferably not all of the third butyl groups.

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 a carbonic acid vinyl ester of formula (XII).

The solvent is preferably used in a state called anhydrous, that is, the water content is in the range of 1 ppm to 0.1% by weight, which can be determined, for example, by Karl Fischer titration.

In one embodiment of the invention, the electrochemical cell of the invention comprises one or more conductive salts, preferably a lithium salt. Examples of suitable lithium salts are LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiC(C _n F _2n+1 SO ₂ ) ₃ , lithium guanidinium (such as LiN (C _n F _2n+1) SO ₂ ) ₂ , wherein n is an integer in the range of 1 to 20), LiN(SO ₂ F) ₂ , Li ₂ SiF ₆ , LiSbF ₆ , LiAlCl ₄ and the formula (C _n F _2n+1 SO ₂ ) _m A salt of XLi, wherein m is defined as follows: m = 1 when 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 ruthenium.

Preferred conductive salts are selected from the group consisting of LiC(CF ₃ SO ₂ ) ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiPF ₆ , LiBF ₄ , LiClO ₄ , LiPF ₆ and LiN(CF ₃ SO ₂ ) _{2 are} particularly preferred.

In one embodiment of the invention, the electrochemical cell of the present invention comprises one or more separators that mechanically isolate the electrodes. Suitable separators are polymeric films, especially porous polymeric films which are non-reactive with metallic lithium and lithium sulfide and lithium polysulfide. Particularly suitable materials for the separator are polyolefins, especially porous polyethylene in the form of a film and porous polypropylene in the form of a film.

The separator made of polyolefin, especially made of polyethylene or polypropylene, may have a porosity in the range of 35% to 45%. Suitable pore diameters are, for example, in the range from 30 nm to 500 nm.

In another embodiment of the invention, the selected separator may be a separator made of PET non-woven fabric filled with inorganic particles. The porosity of the separators can range from 40% to 55%. Suitable pore diameters are for example in the range from 80 nm to 750 nm.

The battery of the invention has high capacitance and high efficiency after repeated charging The delayed battery death has received attention. The battery of the present invention is well suited for use in automobiles, airplanes, electric bicycles (e.g., pedelec), marine or stationary energy storage. These uses form part of the subject matter of the invention.

The present invention further provides a polymer comprising a polymer chain formed from a substituted and/or unsubstituted, preferably substituted ethylene glycol unit as a monomer unit, wherein more than 95% of the monomer units Up to 100% corresponds to the monomer unit -M1'-, and the monomer unit -M1'- represents a substituted ethylene glycol unit of the formula (III') and/or the formula (IV'): Wherein Met is H, Li, Na or Zn _1/2 , preferably H or Li, especially Li; and n is the same or different and is an integer from 1 to 4, preferably 1 or 2, especially 1; The two monomer units of the formula (IV′)—M1′— may be linked to each other via a disulfide bridge or a polysulfide bridge —(S) _n —(S) _n — especially via a disulfide bridge, wherein the formula (IV′) The two monomer units -M1'- are present in the same polymer chain or in two different polymer chains.

The polymer of the invention consists of the above polymer chains to the extent of more than 50% by weight, preferably more than 80% by weight, in particular more than 95% by weight up to 100% by weight, the polymer chains being more than 95% To the extent of up to 100%, the monomer units of the formula (III') and/or the formula (IV') are formed.

The polymer of the present invention is very suitable as the polymer (A) in the above electrode material of the present invention for a battery.

The invention further provides a process for preparing a polymer comprising a polymer chain formed from a substituted and/or unsubstituted ethylene glycol unit as a monomer unit, wherein more than 95% of the monomer units Up to 100% corresponds to monomer unit -M1'-, and monomer unit -M1'- represents substituted ethylene glycol of formula (III') and/or formula (IV'), preferably formula (IV') unit, Wherein Met is H, Li, Na or Zn _1/2 , preferably H or Li, especially Li; and n is the same or different and is an integer from 1 to 4, preferably 1 or 2, especially 1; The two monomer units of the formula (IV′)—M1′— may be linked to each other via a disulfide bridge or a polysulfide bridge —(S) _n —(S) _n — especially via a disulfide bridge, wherein the formula (IV′) The two monomer units -M1'- are present in the same polymer chain or in two different polymer chains. The process comprises the following reaction steps: a) at a temperature in excess of 100 ° C and a pressure in excess of 1 atm A linear polyepichlorohydrin having a molecular weight _Mw of the formula (V) of from 100 000 g/mol to 3 000 000 g/mol in the presence of a strong protic acid aqueous solution and a polar aprotic solvent: Reacting with thiourea to form an isosulfur containing formula (VI) a polymer of a monomer unit based on a salt, Wherein X ^- is a Cl ^- or a strong protonic acid anion, and optionally comprises a monomer unit having a thiol group of the formula (III'), wherein Met is H; b) optionally in the presence of a phase transfer catalyst Containing isosulfur with formula (VI) a salt-based monomer unit and the polymer obtained in process step a) is reacted with an aqueous base solution to eliminate urea and form a polymer comprising a substituted ethylene glycol unit of formula (III'), wherein Met is H; And optionally reacting the polymer obtained in process step b) with an oxidizing agent to form a polymer comprising a substituted ethylene glycol unit of formula (IV') wherein n is 1, wherein two of formula (IV') The ethylene glycol units are in each case connected via a disulfide bridge -S ₂ -, wherein the two ethylene glycol units of the formula (IV') are in the same polymer chain or in two different polymer chains; And d) reacting the polymer obtained in process step c) with elemental sulfur, as appropriate, to form a polymer comprising a polysulfide bridge comprising a substituted ethylene glycol unit of formula (IV'), wherein formula (IV' The two ethylene glycol units are in each case connected via a polysulfide bridge -(S) _n -(S) _n -, wherein n+n is an integer from 3 to 8, and two of formula (IV') The ethylene glycol units are in the same polymer chain or in two different polymer chains.

Linear polyepichlorohydrins having a molecular weight _{Mw of} from 100 000 g/mol to 3 000 000 g/mol used in process step a) are known to those skilled in the art and are commercially available. The average degree of polymerization in formula (V) for such polymers is therefore in the range of from about 1000 to about 33,000.

In process step a) of the process according to the invention, the strong protic acid aqueous solution used may be, for example, hydrochloric acid, sulfuric acid, hydrobromic acid or perchloric acid. Use hydrochloric acid as a strong substance An aqueous acid solution is especially preferred.

The polar aprotic solvent which can be used in step a) of the process according to the invention is, for example, dimethylformamide, N-methyl-2-pyrrolidone, dimethyl hydrazine, diethyl carbonate or tetramethyl Urea. The polar aprotic solvent used is more preferably dimethylformamide.

Thiourea is usually used at least in stoichiometric amounts in terms of the number of chlorine atoms to be substituted. The ratio of thiourea to the chlorine atom to be substituted is preferably at least 2:1, more preferably at least 4:1. The ratio of thiourea to the chlorine atom to be replaced is usually not more than 10:1, preferably not more than 8:1, especially not more than 6:1.

Process step a) of the process of the invention is carried out at a temperature in excess of 100 ° C and a pressure in excess of 1 atm. In general, step a) of the process according to the process of the invention is carried out at a temperature not exceeding 250 °C. The reaction in process step a) is preferably carried out in a pressure vessel at a temperature of from 140 ° C to 160 ° C.

The reaction time in process step a) will generally depend on the temperature of the reaction and the conversion desired. The reaction is preferably carried out for a period of from 1 day to 5 days.

In the process of the invention, in process step b), the inclusion of isosulfur having formula (VI) in the presence of a phase transfer catalyst The salt-based monomer unit and the polymer obtained in process step a) are optionally reacted with an aqueous base solution to eliminate urea and form a polymer comprising a substituted ethylene glycol unit of formula (III'), wherein Met is H .

The aqueous alkali solution used is preferably an aqueous solution of an alkali metal hydroxide or an alkaline earth metal hydroxide, especially an aqueous solution of an alkali metal hydroxide.

Phase transfer catalysts are common knowledge to those skilled in the art. In the process step b) of the process according to the invention, preference is given to using tetraalkylammonium salts, in particular halogenation. Tetraalkylammonium is used as a phase transfer catalyst.

In a preferred embodiment, in process step b), the polymer from process step a) is reacted with aqueous sodium hydroxide in the presence of a catalytic amount of tetrabutylammonium iodide.

In process step b), the reaction is preferably carried out at a temperature ranging from 50 ° C to 100 ° C.

In the process of the invention, in process step c), the polymer obtained in process step b) is optionally reacted with an oxidizing agent to form a polymer comprising substituted ethylene glycol units of formula (IV'), wherein n is 1, wherein the two ethylene glycol units of the formula (IV') are in each case connected via a disulfide bridge -S ₂ - wherein the two ethylene glycol units of the formula (IV') are in the same polymer In the chain or in two different polymer chains.

With regard to the oxidative coupling of two thiol-SHs to obtain a disulfide bridge -S-S-, in principle all oxidizing agents known to the person skilled in the art can be used. Examples of such oxidizing agents are, for example, iodine, bromine, p-benzoquinone, iron (III) chloride or potassium hexacyanoferrate (III). The use of iodine as the oxidizing agent in process step c) is especially preferred.

In process step d) of the process according to the invention, the polymer obtained in process step c) is optionally reacted with elemental sulphur to form a polymerization comprising a polysulfide bridge comprising a substituted ethylene glycol unit of formula (IV') Wherein two ethylene glycol units of the formula (IV') are in each case connected via a polysulfide bridge -(S) _n -(S) _n -, wherein n+n is an integer from 3 to 8, and The two ethylene glycol units of (IV') are in the same polymer chain or in two different polymer chains.

In process step d), the reaction of the polymer obtained in process step c) with elemental sulfur is preferably carried out at a temperature above the melting point of the sulfur (β-S ₈ : 119.6 ° C), more preferably between 150 ° C and 170 ° C. It is carried out within the temperature range.

The electrode material of the present invention allows the manufacture of a battery having a high specific capacitance, especially in the case of adding elemental sulfur (component (C)), while at the same time achieving an extension of the life, especially at temperatures below 30 °C.

The invention is illustrated by the following examples, which are not intended to limit the invention.

Unless otherwise stated, the numbers expressed in % are by weight.

I. Synthesis of sulfur-containing polymers I.1 Synthesis of sulfur-containing polymer P1 I.1.a Synthesis of polysulfur salt

5 g of polyepichlorohydrin (M _w = 700 000 g/mol, available from Aldrich) was dissolved in 100 ml of DMF overnight by means of an oscillator. Subsequently, thiourea (21 g, 270 mmol) was dissolved in DMF (50 ml) in a pressure tube and mixed with a polymer solution and hydrochloric acid (2 M, 15 ml). The obtained viscous mixture was heated to 150 ° C for 48 hours, during which formation of a colorless precipitate was observed. After cooling, carefully open the pressure tube. The solid which formed was filtered off and washed with water (200 ml), hydrochloric acid (2M, 100 ml) and water (200 ml). The aqueous solid was frozen at -30 ° C and dried on a freeze dryer for 48 hours. 5.3 g of a colorless powder was isolated. Characterization was achieved using elemental analysis and ATR-IR.

IR (net): 2914 m, 2867 m, 2054 w, 1652 w, 1461 w, 1409 w, 1342 w, 1093 s, 561 m cm ^-1 .

Elemental analysis:

I.1.b synthesizes polymer P1 containing polydisulfide bridge

Initially, 5.18 g of the sulfur-containing polymer from stage I.1.a was charged into a round bottom flask together with 311 mg of tetrabutylammonium iodide (catalytic amount), and benzene (110 ml) and sodium hydroxide solution (6.7) were added. g, 168 mmol, 27 ml water), and the mixture was heated to reflux for 48 hours, during which time a homogeneous solution was generally observed only after a longer period of time. After cooling, some iodine crystals were added (until the purple color no longer disappeared) and the mixture was stirred at room temperature for 1 hour. To accelerate the formation of the precipitate, the solution was acidified with hydrochloric acid (2 M). The precipitate was filtered and washed with EtOAc (EtOAc) (EtOAc). The aqueous solid was frozen at -30 ° C and dried on a freeze dryer for 48 hours. 2.5 g of a colorless solid (P1) was isolated. Characterization was achieved using elemental analysis and ATR-IR.

IR (net): 2911 m, 2862 m, 1053 s, 561 m cm ^-1 .

Elemental analysis

II. Manufacturing electrode materials and electrodes II.1 Process P1 to obtain cathode K1 of the present invention

2.3 g of polymer P1 and 2.3 g of elemental sulfur were sufficiently homogenized in a mortar to obtain a polymer-sulfur mixture P1-S-1.

A solution of 0.25 g of polyvinyl alcohol in a 82 g water-isopropanol mixture (weight ratio 65:35) was prepared in a laboratory glass vial. To make the ink, 4.4 g of polymer-sulfur mixture P1-S-1, 1 g of carbon black 1 (Ketjen ^® , BET surface area: 900 m ² /g (measured according to ISO 9277), average particle size: 10 [mu] m) and 2 1 g of carbon black (Printex ^® commercially available in, a BET specific surface area: 100 m ² / g (measured according to ISO 9277 carried out), average particle diameter: 10 μm) and the mixture was stirred. For dispersion, the mixture was transferred to a stainless steel grinding vessel, followed by a ball mill (Pulverisette 6, available from Fritsch), and stirred with a stainless steel ball at 300 rpm for 30 minutes. Disperse to form a highly homogeneous creamy viscous ink. The ink was sprayed onto an aluminum foil (thickness: 30 μm) on a vacuum table (temperature: 75 ° C) by a spray gun method. Spray with nitrogen. A solid load of 4 mg/cm ^{2 was} reached. Thereafter, one side of the coated aluminum foil was carefully laminated between the two rubber rolls. A lower applied pressure is chosen to keep the coating porous. Subsequently, the coated aluminum foil on one side was heat-treated at a temperature of 40 ° C in a dry box.

III. Testing the cathode in an electrochemical cell

The electrochemical cell according to Fig. 1 was constructed for electrochemically characterizing the electrode material of the invention produced from the polymer P1 of the invention and the cathode K1 produced therefrom. For this purpose, the following components and the cathode produced in II. are used in each case: anode: Li foil, thickness 50 μm; Separator: polyethylene film, porous film having a thickness of 15 μm; cathode: according to Example II.

Electrolyte: 8% by weight of LiTFSI (LiN(SO ₂ CF ₃ ) ₂ ), 46% by weight of 1,3-dioxolane and 46% by weight of 1,2-dimethoxyethane.

Figure 1 shows a schematic structure of a disassembled electrochemical cell for testing the electrode material of the present invention.

The annotation in Figure 1 means:

1,1' mold

2, 2' nut

3, 3' seal ring, in each case two, this figure does not show a slightly smaller second seal ring in each case

4 coil spring

5 Output conductor made of nickel

6 outer casing

The electrochemical cell of the present invention exhibits an open circuit potential of 2.45 volts. During discharge (C/5), the battery potential drops to 2.2 to 2.3 volts (balanced for the first time) and then drops to 2.0 to 2.1 volts (the second time reaches equilibrium). The battery is discharged to 1.8 V and then charged. During the charging operation, the battery potential rises to 2.2 volts and the battery is charged until it reaches 2.5 volts. Thereafter, a one hour charging step was carried out at 2.5 volts. Then the discharge operation is started again. The fabricated electrochemical cell of the present invention can achieve more than 30 cycles with only minimal capacitance loss.

1, 1 '‧‧‧ mould

2, 2'‧‧‧ nuts

3, 3' ‧ ‧ seal ring, in each case two, this figure does not show a slightly smaller second seal ring in each case

4‧‧‧Coil spring

5‧‧‧Output conductor made of nickel

6‧‧‧Shell

Figure 1 shows a disassembled electrochemical cell used to test the electrode material of the present invention Schematic structure.

1, 1 '‧‧‧ mould

2, 2'‧‧‧ nuts

3, 3' ‧ ‧ seal ring, in each case two, this figure does not show a slightly smaller second seal ring in each case

4‧‧‧Coil spring

5‧‧‧Output conductor made of nickel

6‧‧‧Shell

Claims (15)

An electrode material for a battery comprising: (A) a polymer comprising a C ₂ -C ₁₀ alkanediol selected from the group consisting of substituted and unsubstituted vinyl units and substituted and unsubstituted C ₂ -C ₁₀ alkanediols means the same or different monomer units of the group is formed and comprises at least one monomer unit of the polymer chain -M1-, the monomer units comprise at least one -M1- thiolate -S ^- disulfide bridges or sulfur or At least one end of the bridge -(S) _m - wherein m is an integer from 2 to 8, the thiol group or the end of the disulfide bridge or polysulfide bridge -(S) _m - is directly bonded in each case a carbon atom of the monomer unit -M1-; (B) a carbon in the form of a polymorph comprising at least 60% sp ² mixed carbon atoms; (C) elemental sulfur as the case may be; and (D) at least as the case may be One other polymer acts as a binder material. The electrode material of claim 1, wherein at least 60% of the monomer units of the polymer chains forming the polymer (A) correspond to the monomer unit -M1-. The electrode material of claim 1 or 2, wherein the monomer unit -M1- in the polymer chain of the polymer (A) is a substituted vinyl unit of the formula (I) and/or formula (II): Or a substituted ethylene glycol unit of formula (III) and/or formula (IV): The electrode material according to any one of claims 1 to 3, wherein the second end of the disulfide bridge or the polysulfide bridge -(S) _m - is a part of another monomer unit -M1, the other monomer The unit -M1 is present in the same polymer chain as the first monomer unit -M1- or in another polymer chain of the polymer (A). The electrode material of any one of claims 1 to 4, wherein the carbon (B) is selected from the group consisting of carbon black. The electrode material according to any one of claims 1 to 5, wherein a mass ratio of the polymer (A) to the elemental sulfur (C) is in the range of 1:100 to 100:1. A battery comprising at least one electrode manufactured from the electrode material of any one of claims 1 to 6 or manufactured using the electrode material according to any one of claims 1 to 6. The battery of claim 7, further comprising at least one electrode comprising metallic lithium. A battery according to claim 7 or 8, which comprises a liquid electrolyte comprising a lithium-containing conductive salt. The battery according to any one of claims 7 to 9, which comprises at least one selected from the group consisting of polymers, cyclic ethers and acyclic ethers, acyclic acetals and cyclic acetals, and cyclic organic carbonates and acyclic organic carbonates. Non-aqueous solvent. A polymer comprising a polymer chain formed from a substituted and/or unsubstituted ethylene glycol unit as a monomer unit, wherein more than 95% of the monomer units correspond to the monomer unit -M1'- The monomer unit -M1'- represents a substituted ethylene glycol unit of the formula (III') and/or the formula (IV'): Wherein Met is H, Li, Na or Zn _1/2 , and n is the same or different and is an integer from 1 to 4, and the two monomer units of the formula (IV′) — M1′ — may be via a disulfide bridge or The polysulfide bridges -(S) _n -(S) _n - are linked to each other, wherein the two monomer units -M1'- of the formula (IV') are present in the same polymer chain or are present in two different polymers In the chain. A method of preparing a polymer comprising a polymer chain formed from a substituted and/or unsubstituted ethylene glycol unit as a monomer unit, wherein more than 95% of the monomer units correspond to a monomer Unit -M1'-, the monomer unit -M1'- represents a substituted ethylene glycol unit of formula (III') and/or formula (IV'): Wherein Met is H, Li, Na or Zn _1/2 , and n is the same or different and is an integer from 1 to 4, and the two monomer units of the formula (IV′) — M1′ — may be via a disulfide bridge or The polysulfide bridges -(S) _n -(S) _n - are linked to each other, wherein the two monomer units -M1'- of the formula (IV') are present in the same polymer chain or are present in two different polymers In the chain, the method comprises the following reaction steps: a) at a temperature exceeding 100 ° C and a pressure exceeding 1 atm, in the presence of a strong protic acid aqueous solution and a polar aprotic solvent, the molecular weight M _w of the formula (V) is Linear polyepichlorohydrins from 100 000 g/mol to 3 000 000 g/mol: Reacting with thiourea to form an isosulfur containing formula (VI) a polymer of a monomer unit based on a salt, Wherein X ^- is a Cl ^- or a strong protonic acid anion, and optionally comprises a monomer unit having a thiol group of the formula (III'), wherein Met is H; b) optionally in the presence of a phase transfer catalyst Containing isosulfur with formula (VI) a salt-based monomer unit and the polymer obtained in process step a) is reacted with an aqueous base to eliminate urea and form a polymer comprising a substituted ethylene glycol unit of formula (III'), wherein Met is H; c) reacting the polymer obtained in process step b) with an oxidizing agent, as appropriate, to form a polymer comprising a substituted ethylene glycol unit of formula (IV') wherein n is 1, wherein formula (IV') The two ethylene glycol units are in each case connected via a disulfide bridge -S ₂ - wherein the two ethylene glycol units of the formula (IV') are in the same polymer chain or in two different polymers And d) reacting the polymer obtained in process step c) with elemental sulfur, as appropriate, to form a polymer comprising a polysulfide bridge comprising a substituted ethylene glycol unit of formula (IV'), wherein The two ethylene glycol units of the formula (IV') are in each case connected via a polysulfide bridge -(S) _n -(S) _n -, wherein n+n is an integer from 3 to 8, and the formula (IV) The two ethylene glycol units of ') are in the same polymer chain or in two different polymer chains. The method of claim 12, wherein a linear polyepichlorohydrin having a molecular weight _{Mw of} from 400 000 g/mol to 1 000 000 g/mol is used in process step a). The method of claim 12 or 13, wherein the reaction in method step a) is carried out in a pressure vessel at a temperature of from 140 °C to 160 °C. A use of a battery according to any one of claims 7 to 10 for use in an automobile, an electric bicycle, an aircraft, a ship or a fixed energy storage.