Cathode having a fluorine-containing polymer and solid-state battery using the same

Abstract

The present invention relates to a cathode (26) for a solid-state battery (10), the cathode (26) comprising the following components: (A) at least one cathode active material (20); (B) at least one first fluorine-containing polymer (22) having an at least partially fluorinated or perfluorinated backbone. The first fluorine-containing polymer (22) comprises at least one ionic group of formula (I): M is a cation selected from the group consisting of protons and alkali metals, n is an integer from 1 to 4, and Z is a central ion selected from the group consisting of aluminum and boron. R is C1-C8-alkyl, C2-C3-alkyl, C4-C5-alkyl, C6-C7-alkyl, C8-C9-alkyl, C9-C10-alkyl, C11-C12-alkyl, C12-C14-alkyl, C13-C15-alkyl, C14-C16-alkyl, C15-C17-alkyl, C16-C18-alkyl, C17-C19-alkyl, C18-C20-alkyl, C19-C21-alkyl, C19-C22-alkyl, C20-C23-alkyl, C21-C24-alkyl, C22-C36-alkyl, C22-C37-alkyl, C22-C38-alkyl, C22-C39 ... 10 -Alkenyl, C2-C 10 -Alkynyl, C6-C 12 -Cycloalkyl and C6-C 12 -aryl. The ionic group is bonded to the backbone of the first fluorine-containing polymer (22) through at least one bridging oxygen atom of the ionic group. JPEG2024545403000016.jpg19170

Description

[Technical field]

[0001] The present invention relates to a cathode and a solid-state battery including the cathode. [Background technology]

[0002] In the following, the term "solid-state battery" is used synonymously with all terms commonly used in the prior art for galvanic devices and cells that use at least one solid electrolyte as an ionically conductive connection between the cathode and the anode, such as metal solid-state batteries, metal solid-state accumulators, all-solid-state batteries (ASSBs), cells, solid-state cells, polymer cells and accumulators. In particular, rechargeable batteries (secondary batteries) are included. Also, the terms "battery", "cell" and "electrochemical cell" are used synonymously with the term "solid-state battery".

[0003] Solid-state batteries are a further development of batteries with liquid electrolytes: the porous separator immersed in the liquid, which transports ions and equalizes the charge between the cathode and anode, is replaced by an ionically conductive solid.

[0004] A lithium-ion solid-state battery is a type of solid-state battery.

[0005] Conventionally known lithium ion solid-state batteries have two distinct electrodes: a cathode (positive electrode) and an anode (negative electrode). In lithium ion solid-state batteries, the cathode consists of a cathode active material that can reversibly absorb or release lithium ions. The anode may consist of an anode active material, which consists of either lithium metal, a lithium-containing alloy, or an alternative material that is also designed to reversibly absorb or release lithium ions. Commonly used materials in the prior art include, for example, graphite, silicon, silicon suboxide (SiO x , O <x<2)である。

[0006] If the anode of a lithium-ion solid-state battery does not contain lithium metal immediately after fabrication, but lithium metal is at least partially precipitated during the first charging step, this is referred to as the concept of a "lithium-free" anode. In this context, "lithium-free" means that the anode does not contain metallic lithium in the uncharged state after fabrication and before the cell is formed. Metallic lithium is only formed in the anode after the corresponding charging process.

[0007] Moreover, the solid separator spatially separates the cathode and the anode. The solid separator ensures the transport of lithium ions between the cathode and the anode. Thus, the solid separator conducts electric current by transporting lithium ions in a solid state. Therefore, the solid separator is a solid lithium ion conductor.

[0008] Solid separators can be classified into ceramic solid electrolytes, polymer-based solid electrolytes, and gel-based solid electrolytes. In particular, sulfide-based and oxide-based solid electrolytes are used as ceramic solid electrolytes, and are gaining importance due to their electrochemical stability and high lithium ion conductivity. On the other hand, polymer-based solid electrolytes are solvent-free and based on ion conduction along the polymer chain. For example, polyethylene oxide mixed with lithium-containing conductive additives can be used as a polymer-based solid electrolyte. Gel-based solid electrolytes include a solid polymer matrix that is permeated with a liquid electrolyte that ensures ion conduction.

[0009] US2019 / 0157723A1 describes a lithium-ion solid-state battery comprising a cathode having a cathode active material and an anode having an anode active material. Furthermore, the anode comprises an anode current collector. The anode active material is selected so that it can form an alloy or compound with metallic lithium. The anode active material and the cathode active material are spatially separated by a solid electrolyte. The solid electrolyte consists of a sulfide such as Li6PS5Cl having an argyrodite structure. The cathode active material consists of a known lithium-containing layered oxide, in particular NMC. The anode active material can be selected from the group consisting of amorphous carbon, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, and combinations thereof.

[0010] The above-mentioned lithium-ion solid-state battery adopts a lithium-free anode concept, in which metallic lithium is precipitated between the anode current collector and the anode active material during the initial charging process, so that metallic lithium does not exist in the cell after fabrication from the beginning.

[0011] WO2020 / 0725524A1 discloses a lithium-ion solid-state battery including an anode current collector, a solid electrolyte, and a transition layer between the anode current collector and the solid electrolyte. The transition layer is selected from the group consisting of zinc, tin, magnesium, silver, aluminum, indium, bismuth, lithium alloys, lithium oxide, and lithium peroxide, and combinations thereof. In particular, the solid electrolyte is a lithium-containing garnet, preferably of the formula Li7La3Zr2O 12 The lithium-ion battery is composed of lithium lanthanum zirconate (LLZO), which ensures charge balancing between the anode and the cathode by transporting lithium ions. Again, a lithium-free anode concept is used.

[0012] Ceramic solid electrolytes are known from US 2021 / 01226281 A1 and can be described by the following general formula: Li 1-a-b-c-d P a T bA c X d Here, 0 ≤ a ≤ 0.129, 0 ≤ b ≤ 0.096, 0.316 ≤ c ≤ 0.484, 0.012 ≤ d ≤ 0.125, T is an element from the group consisting of As, Si, Ge, Al, and B, X is one or more halogens or N, and A is one or more S and Se.

[0013] WO2019 / 051305A1 discloses a cathode, an anode, and a solid electrolyte disposed between the cathode and the anode. At least the cathode, anode, or solid electrolyte is made of a ceramic material containing lithium (Li), boron (B), and sulfur (S). The ceramic material exhibits a plurality of crystal phases and has an overall composition characterized by the a:b:c molar ratio of Li:B:S, where c / b ranges from about 1 to about 3.

[0014] EP3496202A1 discloses a lithium ion conductive lithium yttrium halide of the general formula Li 6-3z Y z X6 (where 0 < z < 2 and X is Cl or Br). This lithium yttrium halide is used as a solid electrolyte in a lithium ion solid battery.

[0015] US10811688B2 and US2017 / 0338492A1 disclose a lithium ion solid battery having an ion conductive polymer-based solid electrolyte, an ion source, such as Li2O, Na2O, MgO, CaO, ZnO, KOH, NaOH, CaCl2, AlCl3, MgCl2, LiTFSI (lithium bis-trifluoromethanesulfonimide), LiBOB (lithium bis(oxalate) borate), or a combination thereof, and an electron acceptor. Examples of the lithium ion conductive polymer include liquid crystal polymer, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and semi-crystalline polymers with a crystallinity of 30% or more.

[0016] US2019 / 0051939A1 shows a lithium-ion solid-state battery comprising polylithium acrylate as a polymer-based solid electrolyte. The solid electrolyte further comprises a hydrophilic polymer, a lithium salt and a Lewis acid.

[0017] In order to ensure sufficient ionic conduction between the electrode and the solid electrolyte, intimate contact between the active material of the cathode and the solid electrolyte is necessary. For this purpose, the solid electrolyte is incorporated into the cathode. This is done by providing a mixture of the solid electrolyte and the active material, the so-called composite electrode.

[0018] However, the combination of a solid electrolyte and a cathode active material poses a number of problems.

[0019] During normal operation of a lithium-ion solid-state battery, the constant relithiation and delithiation of the active materials can lead to volume changes within these materials. Such volume changes can lead to mechanical stresses within the cell over time. These mechanical stresses can induce cracks within the solid electrolyte, compromising the proper operation of the cell. Cracking is particularly problematic in hard ceramic solid electrolytes.

[0020] Additionally, ceramic solid electrolytes often require a sintering step during manufacture at temperatures between 650° C. and 1200° C. However, such temperatures can irreparably damage the composite cathode, especially the cathode active material present in the composite cathode.

[0021] Either an organic binder or a polymer electrolyte such as polyethylene oxide (PEO) in the cathode composite can offer a remedy, but organic binders lack ionic conductivity and the oxidative stability of polymers such as PEO is often insufficient for the potentials of the cathode electrode materials (4 V and above). [Prior art documents] [Patent documents]

[0022] [Patent Document 1] US2019 / 0157723A1 [Patent Document 2] WO2020 / 0725524A1 [Patent Document 3] US2021 / 01226281A1 [Patent Document 4] WO2019 / 051305A1 [Patent Document 5] EP3496202A1 [Patent Document 6] US10811688B2 [Patent Document 7] US2017 / 0338492A1 [Patent Document 8] US2019 / 0051939A1 Summary of the Invention [Problem to be solved by the invention]

[0023] The invention is based on the problem of providing a solid-state battery which avoids the drawbacks of the solid-state batteries known from the prior art, is easy to manufacture and can operate stably for a longer period of time. [Means for solving the problem]

[0024] According to the invention, this problem is solved by providing a cathode for a solid-state battery as claimed in claim 1.

[0025] Advantageous embodiments of the cathode according to the invention for solid-state batteries are set forth in the dependent claims, which can be arbitrarily combined with one another.

[0026] According to the present invention, a cathode for a solid-state battery comprises the following components: (A) at least one cathode active material; (B) at least one first fluorine-containing polymer having an at least partially fluorinated or perfluorinated backbone, wherein the first fluorine-containing polymer contains at least one ionic group of formula (I): [ka] During the ceremony, - M is a cation selected from the group consisting of protons and alkali metals; - n is an integer from 1 to 4; - Z is a central ion selected from the group consisting of aluminum and boron; and R is a monovalent, optionally fluorine-substituted, hydrocarbon residue, C1-C8-alkyl, C2-C 10 -Alkenyl, C2-C 10 -Alkynyl, C6-C 12 -Cycloalkyl and C6-C 12 - selected from the group consisting of aryl; Here, the ionic group is attached to the backbone of the first fluorine-containing polymer through at least one bridging oxygen atom of the ionic group.

[0027] The present invention is based on the basic idea of ​​providing a combination of a cathode active material and a first fluorine-containing polymer for a cathode of a solid-state battery, the combination proposed according to the invention having many advantageous properties.

[0028] Fluorine-containing polymers have ionic groups as an essential feature. The ionic groups allow for almost unhindered ion transport in the cathode. Therefore, the first fluorine-containing polymers are ion conductors. Therefore, there is no need to add classical conductive salts such as lithium hexafluorophosphate. Ion conduction takes place through the fluorine-containing polymer. Due to these functional ionic groups, the first fluorine-containing polymers have a transport number close to 1.

[0029] At the same time, fluorine-containing polymers with at least a partially fluorinated or perfluorinated backbone have high chemical and electrochemical stability, making them particularly suitable for use as cathodes in solid-state batteries.

[0030] In addition, the first fluorine-containing polymer is mechanically flexible and elastic. Therefore, the polymer can compensate for the volume changes of the cathode active material during the operation of the cell. Therefore, the cathode active material can expand and contract again unhindered during relithiation and delithiation. The combination of the cathode active material and the first fluorine-containing polymer can compensate for these volume changes and prevent mechanical stress in the cell.

[0031] In addition, there is a synergistic effect between the cathode active material as the "hard" component and the fluorine-containing polymer as the "soft" component. The fluorine-containing polymer as the "soft" component can preferentially adapt to the rigid shape of the cathode active material, thereby increasing the contact area and ensuring ionic conduction between the fluorine-containing polymer and the cathode active material.

[0032] Suitable cathode active materials for the cathode can be any cathode active material known in the art.

[0033] Preferred cathode active materials for the cathode according to the present invention include lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium and manganese rich lithium nickel manganese cobalt oxide or lithium nickel manganese oxide (LMR), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium nickel manganese oxide spinel (LNMO) and its derivatives lithium, and combinations thereof.

[0034] Lithium-nickel-manganese-cobalt compounds are also known by the abbreviation NMC and sometimes by the technical abbreviation NCM. NMC-based cathode materials are used in particular in automotive lithium-ion batteries. NMC as a cathode material has a favorable combination of desirable properties, such as high specific capacity, reduced cobalt content, high high current capability, and high inherent safety, as demonstrated, for example, by sufficient stability during overcharging.

[0035] NMC is a compound of the general formula Li α Ni x Mn y Co z O2, x+y+z=1, where α indicates the stoichiometric proportion of lithium, typically 0.8-1.15. Some stoichiometries are described in the literature as triplet numbers, e.g. NMC811, NMC622, NMC532, NMC111. The triplet number indicates the relative contents of nickel:manganese:cobalt in each case. That is, for example, NMC811 has the general formula unit LiNi 0.8 Mn 0.1 Co 0.1 O2, i.e., α=1. Furthermore, the general formula unit Li 1+ε (Ni x Mn y Co z ) 1-ε The so-called lithium- and manganese-rich NMC or LMR of O2 can also be used, where ε is in particular between 0.1 and 0.6, preferably between 0.2 and 0.4. These lithium-rich layered oxides are also known as overwritten (layered) oxides (OLO).

[0036] According to the present invention, the first fluorine-containing polymer comprises at least one ionic group of general formula (I).

[0037] The ionic group is the cation M + , anion [-(O) n -Z-(OR) 4-n ] - It is an ion containing

[0038] In general formula (I), the negative charge of the anion is stoichiometrically balanced by the positive charge of the cation.

[0039] The cation is selected from the group consisting of a proton and an alkali metal, preferably the cation is lithium.

[0040] In formula (I), Z is a central ion selected from the group consisting of aluminum and boron. Thus, the ionic group is either an aluminate or a borate, and the anion in formula (I) is correspondingly singly negatively charged.

[0041] Each residue R represents a monovalent, optionally fluorine-substituted, hydrocarbon residue, C1-C8-alkyl, C2-C 10 -Alkenyl, C2-C 10 -Alkynyl, C6-C 12 -Cycloalkyl and C6-C 14 -aryl. For the purposes of the present invention, monovalent means that each hydrocarbon residue R is attached to the central ion Z via a single oxygen atom.

[0042] For the purposes of the present invention, the term C1-C8-alkyl includes linear or branched saturated hydrocarbon residues having 1 to 8 carbon atoms. Preferred hydrocarbon residues include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, 2,2-dimethylpropyl, n-hexyl, iso-hexyl, 2-ethylhexyl, n-heptyl, iso-heptyl, n-octyl and iso-octyl.

[0043] For the purposes of this invention, C2-C 10The term -alkenyl includes linear or branched, at least partially unsaturated hydrocarbon residues having 2 to 10 carbon atoms, the hydrocarbon residue having at least one C-C double bond. Preferred hydrocarbon residues include, for example, ethenyl, 1-propenyl, 2-propenyl, 1-n-butenyl, 2-n-butenyl, iso-butenyl, 1-pentenyl, 1-hexenyl, 1-heptenyl, 1-octenyl, 1-nonenyl and 1-decenyl.

[0044] For the purposes of this invention, C2-C 10 The term -alkynyl includes linear or branched, at least partially linear, unsaturated hydrocarbon residues having 2 to 10 carbon atoms, the hydrocarbon residue having at least one C-C triple bond. Preferred hydrocarbon residues include, for example, ethynyl, 1-propynyl, 2-propynyl, 1-n-butynyl, 2-n-butynyl, iso-butynyl, 1-pentynyl, 1-hexynyl, 1-heptynyl, 1-octynyl, 1-nonyl and 1-decynyl.

[0045] For the purposes of this invention, C6-C 12 The term -cycloalkyl includes cyclic saturated hydrocarbon residues having 6 to 12 carbon atoms. Preferred hydrocarbon residues include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclohexyl, cyclononyl and cyclodecanyl.

[0046] For the purposes of this invention, C6-C 14 The term -aryl includes aromatic hydrocarbon residues having 6 to 12 carbon atoms. Preferred hydrocarbon residues include, for example, phenyl, naphthyl and anthracyl.

[0047] In a preferred embodiment, the hydrocarbon residue R is at least partially fluorinated, preferably fully fluorinated.

[0048] Fluorine-substituted hydrocarbon residues provide anions which form particularly stable ionic groups of formula (I).

[0049] n is an integer from 1 to 4, and thus defines the number of bonds of the central ion Z to the at least partially fluorinated or perfluorinated backbone of the first fluorine-containing polymer. The central ion Z is always bonded to the first fluorine-containing polymer via at least one bridging oxygen atom of the ionic group.

[0050] The number of residues -OR is given as 4-n in general formula (I). Thus, the number of residues -OR is directly connected to the number of bonds (n) of the central ion Z to the at least partially fluorinated or perfluorinated backbone of the first fluorine-containing polymer.

[0051] The degree of bonding of the ionizable group can be set by n. In general, the choice of n gives two types of bonding: Ionic end groups (n=1); and Ionic crosslinking groups (n=2, 3 or 4)

[0052] In one embodiment, the first fluorine-containing polymer has at least one ionic end group of general formula (I), where n is 1.

[0053] When n in formula (I) is equal to 1, the central ion Z is bonded to the backbone of the first fluorine-containing polymer via a bridging oxygen atom in an ionic group. Such a central ion Z is bonded to three -residues OR. An example of such an ionic end group is given by the following formula (II): [ka]

[0054] In a further embodiment, the first fluorine-containing polymer has at least one ionic crosslinking group of general formula (I), where n is 2, 3 or 4.

[0055] When n in formula (I) is equal to 2, the central ion Z is bonded to the backbone of the first fluorine-containing polymer through two bridging oxygen atoms in the ionic group. Such a central ion Z is then bonded to two residues -OR. An example of such an ionic structure is given by the following formula (III): [ka]

[0056] When n in formula (I) is equal to 3, the central ion Z is bonded to the backbone of the first fluorine-containing polymer through three bridging oxygen atoms in the ionic group. Such a central ion Z is then bonded to the residue -OR. An example of such an ionic structure is shown in formula (IV) below: [ka]

[0057] When n in formula (I) is equal to 4, the central ion Z is connected to the ionic group via four bridging oxygen atoms. The central ion Z is bonded to the backbone of the first fluorine-containing polymer. Such a central ion Z is not bonded to any -OR residue. An example of such an ionic structure is shown in the following formula (V): [ka]

[0058] Generally, the first fluorine-containing polymer can have both the ionic end group of formula (II) and the ionic crosslinking group of formula (III)-(V).However, it is also possible that the first fluorine-containing polymer contains only the ionic end group or only the ionic crosslinking group.

[0059] In a preferred embodiment, the general formula (I) has at least one of the following characteristics: · Z stands for Aluminum; · M stands for lithium. R represents a linear, branched or cyclic C1-C4-perfluoroalkyl residue.

[0060] For the purposes of the present invention, the term C1-C4-perfluoroalkyl (perfluorinated alkyl) consists of a linear or branched saturated perfluorohydrocarbon residue having 1 to 4 carbon atoms.

[0061] Examples of suitable perfluoroalkyl radicals are trifluoromethyl, perfluoro-ethyl, perfluoro-propyl, perfluoro-isopropyl, perfluoro-n-butyl, perfluoro-sec-butyl, perfluoro-iso-butyl and perfluoro-tert-butyl.

[0062] In a particularly preferred embodiment, the ionic group is an ionic end group of formula (VI): [ka]

[0063] In one embodiment, the backbone of the first fluorine-containing polymer is fully fluorinated and has a repeat unit of tetrafluoroethylene (-C2F4-). Thus, the backbone of the first fluorine-containing polymer is derived from polytetrafluoroethylene (PTFE). Furthermore, the backbone is unbranched (linear) and essentially consists of fluorine and carbon.

[0064] The first fluorine-containing polymer may include at least one perfluoro side chain, which serves to connect the backbone with the ionic group of general formula (I).

[0065] The present invention is not limited with respect to the perfluoro side chains. All perfluoro side chains known in the prior art for perfluoropolymers may be present. In particular, the perfluoro side chains known from DE 2817315, referred to here, may be used.

[0066] In a preferred embodiment, the backbone of the first fluorine-containing polymer comprises at least one side chain of the following formula (VII): [ka] During the ceremony, - Y is a fluorine atom or a linear, branched or cyclic C1-C8-perfluoroalkyl residue; - m is 0, 1 or 2; - v is 0 or 1; Here, the ionic group of general formula (I) is attached to the side chain CY2 residue.

[0067] The central ion Z of the ionizable group of general formula (I) can be linked to the CY2 residue of the side chain via a bridging oxygen atom of the ionizable group, the side chain thus representing the linking element between the backbone and the ionizable group.

[0068] Ionic end group is only connected to the backbone of the first fluorine-containing polymer through one side chain. Ionic crosslinking group is connected to the backbone of the fluorine-containing polymer through several side chains instead. However, it is also considered that ionic crosslinking group crosslinks the backbone of multiple first fluorine-containing polymers.

[0069] For example, when n is equal to 2 in general formula (I), the ionic crosslinking group is attached to the backbone of the first polymer through two side chains.

[0070] In a further embodiment, the first fluorine-containing polymer is a copolymer of formula (VIII) or (IX): [ka] During the ceremony - m is 0, 1 or 2; - p is 1 to 10; - r is between 1 and 10; - s is 1 to 15; and - Y is a fluorine atom or a linear, branched or cyclic C1-C10 - represents a perfluoroalkyl residue; and - T represents an ionic group of general formula (I).

[0071] Here again, the ionic group T of general formula (I) is bonded to the -CY2 residue. In this way, the ionic group of general formula (I) can be easily incorporated into a fluorine-containing polymer.

[0072] Furthermore, the fluorine substitution renders the side chains chemically stable against oxidative stress during operation of the cell.

[0073] The first fluorine-containing polymer can be prepared by synthesizing a hydroxyl-containing fluoropolymer, which is prepared by dissolving perfluorohexane (CF) in the presence of a perfluoroalcohol. 14 ) at 70-80° C. with lithium aluminum hydride (LiAlH4). The cathode may further comprise a second fluorine-containing polymer, the second fluorine-containing polymer being selected from the group of sulfonated perfluoropolymers.

[0074] The invention is not further limited with respect to the sulfonated perfluoropolymer: in principle, all sulfonated perfluoropolymers commonly used in the prior art can be used.

[0075] For example, polymers known from DE 2817315 can be used.

[0076] In a preferred embodiment, the sulfonated perfluoropolymer is based on or derived from polytetrafluoroethylene, such as NAFION®.

[0077] In a further embodiment, the sulfonated perfluoropolymer has perfluoroalkyl side chains that have functional groups.

[0078] The second fluorine-containing polymer is not limited with respect to the functional group of the perfluoroalkyl side chain.In principle, as long as it is ionic and has lithium ion as cation, all functional groups commonly used in the prior art can be used in the perfluoroalkyl side chain.

[0079] Preferably, the polytetrafluoroethylene-based sulfonated perfluoropolymer is a sulfonated perfluoropolymer containing SO3Li, SO2-N - Li + Contains -SO2CF3- and / or SO2C(CN)2Li-containing perfluoroalkyl side chains.

[0080] A suitable example of a SO2C(CN)2Li-containing perfluoroalkyl side chain is the structure of formula (X): [ka]

[0081] A suitable example of a SO3Li-containing perfluoroalkyl side chain is the structure of formula (XI): [ka]

[0082] SO2-N - Li + A suitable example of a -SO2CF3- containing perfluoroalkyl side chain is the structure of formula (XII): [ka]

[0083] The perfluoroalkyl side chain is not limited with respect to the above examples, and in particular is not limited to the perfluoroethoxy and perfluoroisopropoxy groups shown. In principle, the proposed SO3Li-containing, SO2-N - Li +The -SO2CF3- and / or SO2C(CN)2Li-containing perfluoroalkyl side chains can have any branched or unbranched perfluoroalkoxy group.

[0084] Preferably, the lithium content of the cathode can be specifically adjusted by introducing a second fluorine-containing polymer. In addition, the lithium ion conductivity of the cathode can also be adjusted. The lithium ion conductivity is adjusted mainly by selecting the functional group of the perfluoroalkyl side chain. In this way, the second fluorine-containing polymer becomes a second lithium ion conductor.

[0085] In a preferred embodiment, the cathode comprises at least one solvent component selected from the group consisting of perfluorocarbonates, perfluoroaromatics, perfluoroethers and perfluoroesters, and combinations and derivatives thereof.

[0086] For example, hexafluorobenzene can be used as the perfluoroaromatic.

[0087] Particularly preferably, the solvent component forms a gel with the first and / or second fluorine-containing polymer. This gel performs the function of the gel electrolyte to ensure ion transport in the cathode. The gel electrolyte is mechanically flexible and can compensate for the volume change of the cathode active material during cell operation. This can prevent the solid-state battery from being damaged by mechanical stress.

[0088] In a particularly preferred embodiment, the cathode comprises the following components, each of which is based on the total weight of the cathode: (A) 40 to 98 weight percent of at least one cathode active material; (B) 0.1 to 30 mass % of at least one first fluorine-containing polymer; (C) SO3Li-containing, SO2-N - Li +0-30% by weight of at least one second fluorine-containing polymer selected from the group of sulfonated perfluoropolymers, preferably based on polytetrafluoroethylene (PTFE) having -SO2CF3- and / or SO2C(CN)2Li-containing perfluoroalkyl side chains; and (D) 0 to 70% by weight, preferably 0.1 to 70% by weight, of at least one solvent component consisting of perfluorocarbonates, perfluoroaromatics, perfluoroethers and perfluoroesters, and combinations and derivatives thereof; Here, the proportions of the components (A) to (D) are 100 mass %.

[0089] Furthermore, the cathode may contain other additives known from the prior art, such as binders and conductive additives, the invention being not limited with respect to the further additives.

[0090] The present invention also relates to a solid-state battery comprising a cathode, an anode, and a solid separator spatially separating the cathode and the anode and having ionic conductivity with the cathode and the anode.

[0091] The solid separator includes at least one ceramic polymer-based or gel-based solid electrolyte, or a combination thereof.

[0092] The invention is not limited with respect to the solid electrolyte used as the solid separator: in principle, all separators based on solid electrolytes known in the prior art can be used.

[0093] The solid separator may be composed of at least one solid electrolyte, in particular at least one ceramic solid electrolyte, a polymer-based solid electrolyte, or a gel-based solid electrolyte, and combinations thereof.

[0094] In one embodiment, the solid electrolyte has the general formula Li c T y S zR q containing lithium phosphide sulfide and / or lithium boride sulfide having, wherein T is boron or phosphorus, R is halogen, 2 ≦ c ≦ 7, 1 ≦ y ≦ 7, 3 ≦ z ≦ 13, 0 ≦ q ≦ 1.

[0095] A further example of a suitable solid electrolyte is a compound of the general formula known from US2021 / 0126281A1: Li 1-a-b-c-d P a T b A c X d where 0 ≦ a ≦ 0.129, 0 ≦ b ≦ 0.096, 0.316 ≦ c ≦ 0.484, 0.012 ≦ d ≦ 0.125, T is an element selected from the group consisting of As, Si, Ge, Al and B, X is one or more halogens or N, A is one or more of S and Se, and a composition based on lithium (Li), boron (B) and sulfur (S) known from WO2019 / 051305A1, characterized by an a:b:c molar ratio of Li:B:S, and c / b is in the range of about 1 to about 3.

[0096] In another embodiment, the solid electrolyte comprises a lithium-containing garnet having the general formula Li n La m M’ p M’’ q Zr s O t where 4 < n < 8.5, 1.5 < m < 4, 0 ≦ p ≦ 2, 0 ≦ q ≦ 2, 0 ≦ s ≦ 2.5, and 10 < t ≦ 13, and M’ and M’’ are independently selected from the group consisting of aluminum, molybdenum, tungsten, niobium, antimony, calcium, barium, strontium, cerium, hafnium, rubidium, gallium and tantalum.

[0097] In a further embodiment of the present invention, the lithium-containing garnet has the general formula Li w La v Zr k O hIt contains a compound having -gAl2O3, where 5 ≦ w ≦ 8, 2 ≦ v ≦ 5, 0 ≦ k ≦ 3, 10 ≦ h ≦ 13 and 0 ≦ g ≦ 1.

[0098] In a preferred embodiment, the solid electrolyte is a lithium-containing garnet having the general formula Li j La3Zr b O 12 -gAl2O3, where 5 ≦ j ≦ 8 and 0 < b ≦ 2.

[0099] In particular, a mixture of polyethylene oxide and its derivatives with a lithium-containing conductive salt can be used as a polymer-based solid electrolyte. Further examples include ion-conductive polymers based on liquid crystal polymers, polyetheretherketone (PEEK), polyphenylene sulfide (PPS), and semi-crystalline polymers with a crystallinity exceeding 30%. For example, the compositions known from US2017 / 0338492A1 and US10811688B2 are referred to.

[0100] Furthermore, the solid electrolyte described in US2019 / 0051939A1, which contains poly-lithium acrylate together with a hydrophilic polymer, a lithium salt, and a Lewis acid, can also be used.

[0101] Furthermore, the lithium-ion conductive yttrium lithium halide of the general formula Li 6-3z Y z X6 described in EP3496202A1 can be used as a solid electrolyte, where 0 < z < 2 and X is Cl or Br. Lithium yttrium halide can be used as a solid electrolyte for lithium-ion batteries.

[0102] The solid separator contains at least one solid electrolyte. However, the use of multiple different solid electrolytes can also be considered.

[0103] Preferably, the solid separator comprises one of the oxidative solid electrolytes mentioned above, and particularly preferably comprises a lithium-containing garnet, such as lithium lanthanum zirconate (LLZO).

[0104] Preferably, the solid separator is designed as a layer, which may be single or multi-layered. In particular, there may be several layers with different solid separators. The composition of the layers may be stepped or gradually changed. The oxidizing solid electrolyte is preferably arranged on the anode side.

[0105] The anode includes an anode current collector and, optionally, an anode layer.

[0106] The anode current collector can be made of any material known in the art for use as an anode current collector. Preferably, the anode current collector is made of copper.

[0107] The anode layer of a solid-state battery can include any structure or material known in the art for an anode.

[0108] For example, the anode layer can include an anode active material and / or a seed layer.

[0109] Additionally, the anode layer can be a composite layer comprising a mixture of the anode active material with other components, such as binders, conductive additives, solid electrolytes, and combinations thereof.

[0110] Finally, the anode layer may be a single layer or multiple layers.

[0111] Preferred components for the anode active material of lithium ion solid state batteries include lithium metal, zinc, magnesium, silver, aluminum, indium, tin, bismuth, silicon, silicon suboxide, graphite, silicon-carbon-composites, tin-carbon-composites, silicon alloys, lithium alloys, and combinations thereof.

[0112] In one embodiment, the anode does not contain lithium metal in an uncharged state after fabrication: lithium metal is deposited on the anode only during the charging process after the lithium-ion solid-state battery is fabricated.

[0113] Thus, lithium metal is deposited on the anode current collector, or optionally on a seed layer that can be applied to the anode current collector.

[0114] However, unlike the anode active material, the seed layer cannot completely absorb the lithium metal deposited on the anode during charging of the lithium-ion solid-state battery. For this reason, the seed layer performs a different function than the anode active material, namely the function of controlling the lithium deposition on the anode during the charging process of the lithium-ion solid-state battery. This can already be achieved by using a seed layer having a layer thickness of 1 nm to 10 μm, preferably 5 nm to 3 μm, particularly preferably 10 to 2000 nm. In a further embodiment, a porous seed layer can be provided.

[0115] In general, the seed layer can include the same components as the anode active materials described above, except for lithium or a lithium alloy.

[0116] Suitable examples of seed layer components include zinc, magnesium, silver, aluminum, indium, tin, bismuth, silicon, silicon suboxide, graphite, silicon-carbon-composite, tin-carbon-composite, silicon alloy, and combinations thereof.

[0117] The cathode includes a cathode current collector and a cathode layer on the cathode current collector.

[0118] The cathode current collector can be made of any material known in the art as a cathode current collector. Preferably, the cathode current collector is made of aluminum.

[0119] The cathode layer includes at least one cathode active material and a first fluorine-containing polymer.

[0120] Suitable cathode active materials for the cathode according to the present invention include lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium and manganese rich lithium nickel manganese cobalt oxide, and lithium nickel manganese oxide (LMR), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium nickel manganese oxide spinel (LNMO) and derivatives thereof, and combinations thereof.

[0121] In an advantageous further development of the invention, the solid-state battery is a lithium-ion solid-state battery.

[0122] The lithium-ion solid-state battery comprises a cathode having a cathode layer comprising a cathode active material and a first fluorine-containing polymer, an anode and a solid separator based on a ceramic, in particular an oxidizing solid electrolyte.

[0123] In this embodiment, there is a synergistic effect between the cathode according to the invention and the ceramic solid separator. On the one hand, the fluorine-containing polymer allows for ionic bonding of the cathode with the oxide separator, and on the other hand, the solid separator can be manufactured separately from the cathode. In other words, the ceramic solid separator, in particular the oxidizing solid electrolyte, only needs to be sintered separately at high temperature and then bonded to the cathode. As a result, the cathode does not need to be exposed to high temperatures during manufacture. Nevertheless, the solid electrolyte based on the fluorine-containing polymer used in the cathode according to the invention forms an intimate contact with the ceramic solid electrolyte.

[0124] A further advantageous combination results from the construction of a lithium-ion solid-state battery consisting of the above-mentioned cathode, an oxide solid separator, and an anode comprising an anode layer, the anode layer comprising lithium metal.

[0125] In this arrangement, the ceramic, especially oxidative, solid separator serves as a particularly stable protective layer between the lithium metal of the anode layer and the active material of the cathode layer. Undesirable reactions between the components of the cathode and the lithium metal of the anode can thus be avoided. As a result, no oxidative decomposition occurs on the anode side. On the cathode side, the first fluorine-containing polymer remains intact, since it is spatially separated from the lithium metal of the anode by the protective layer. The performance of the lithium-ion solid-state battery is therefore only slightly or not at all limited.

[0126] The proposed lithium-ion solid-state battery is easy to fabricate and has improved cycling stability.

[0127] The cyclic ageing resistance of a test cell is determined by the number of cycles. The test cell is initially charged with a constant charging current up to the maximum allowed cell voltage. The upper cut-off voltage is kept constant until the charging current drops to a specified value or the maximum charging time is reached. This is also called I / U charging. The test cell is then discharged with a constant discharge current to a specified cut-off voltage. The charging can be repeated for a desired number of cycles. The upper and lower cut-off voltages as well as the given charge and discharge currents must be selected experimentally. This also applies to the reduced values ​​of the charging current. [Brief description of the drawings]

[0128] The present invention will now be described in more detail with reference to the accompanying drawings, in which: FIG. 1 shows a schematic diagram of a lithium-ion solid-state battery comprising only a first fluorine-containing polymer. FIG. 2 shows a schematic diagram of the lithium-ion solid-state battery of FIG. 1 with a second fluorine-containing polymer. FIG. 3 shows a schematic diagram of the lithium-ion solid-state battery of FIG. 2 with a solvent component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0129] 1 shows a lithium ion solid-state battery 10. The lithium ion solid-state battery 10 includes an anode 16 and a cathode 26. The anode 16 and the cathode 26 are ionically connected to each other via a solid separator 18. Furthermore, the solid separator 18 spatially separates the anode 16 from the cathode 26.

[0130] In this case, ionic conduction refers to the conduction of lithium ions within solid separator 18.

[0131] Anode 16 includes an anode current collector 12 and an anode layer 14 on anode current collector 12 .

[0132] Anode current collectors are well known and are typically made of metallic materials. Anode current collector 12 is for making electrical contact with anode layer 14. Anode current collector 12 may be made of copper, for example.

[0133] Anode layer 14 includes at least one active anode material.

[0134] The anode active material is intended to reversibly absorb and release lithium ions, and is preferably composed of a component from the group consisting of lithium metal, zinc, magnesium, silver, aluminum, indium, tin, bismuth, silicon, silicon suboxide, graphite, silicon-carbon-composites, tin-carbon-composites, silicon alloys, and lithium alloys, and combinations thereof.

[0135] The anode active material preferably comprises lithium metal.

[0136] Cathode 26 includes a cathode current collector 24 and a cathode layer 25 on cathode current collector 24 .

[0137] The cathode current collector is typically made of a metallic material such as aluminum.

[0138] Cathode layer 25 exists as a composite and includes a mixture of cathode active material 20 and first fluorine-containing polymer 22. In particular, cathode active material 20 is distributed in a matrix of first fluorine-containing polymer 22.

[0139] The cathode active material 20 is preferably selected from the group consisting of lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium and manganese rich lithium nickel manganese cobalt oxide or lithium nickel manganese oxide (LMR), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium nickel manganese oxide spinel (LNMO), and derivatives and combinations thereof. The cathode active material 20 is designed to reversibly absorb and release lithium ions.

[0140] The first fluorine-containing polymer 22 has a partially fluorinated or perfluorinated backbone and contains at least one ionic group of general formula (I): [ka] During the ceremony, - M is a cation selected from the group consisting of protons and alkali metals; - n is an integer from 1 to 4; - Z is a central ion selected from the group consisting of aluminum and boron; and R is a monovalent, optionally fluorine-substituted, hydrocarbon residue, CC 18 -Alkyl, C2-C 10 -Alkenyl, C2-C 10 -Alkynyl, C6-C 12 -Cycloalkyl and C6-C 12 -aryl; wherein the ionic group is attached to the backbone of the first fluorine-containing polymer through at least one bridging oxygen atom of the ionic group.

[0141] Preferably, in the general formula (I), M is lithium, n is 1, and Z is aluminum. Particularly preferably, the hydrocarbon residue R is a trifluoromethyl residue and / or a perfluoro-tert-butyl residue. Thus, the first fluorine-containing polymer is a lithium ion conductor.

[0142] Additionally, the cathode layer 25 may include at least one binder (not shown here), the binder being selected from the group consisting of polyvinylidene fluoride (PVDF), hydrogenated acrylonitrile butadiene rubber (HNBR), carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), polyacrylate (PAA), lithium polyacrylate (LiPAA) and polyvinyl alcohol (PVA), and combinations thereof.

[0143] The cathode layer 25 may also include a conductive additive (not shown here), which is selected from the group consisting of conductive carbon black, carbon nanotubes, graphene, graphite, and carbon nanofibers, and combinations thereof.

[0144] Solid separator 18 is disposed between anode 16 and cathode 26 and includes at least one ceramic solid electrolyte, a polymer-based solid electrolyte, a gel-based solid electrolyte, or a combination thereof.

[0145] In particular the following compositions can be used as solid electrolytes: - General formula Li c T y S z R q where T is boron or phosphorus, R is a halogen, and 2≦c≦7, 1≦y≦7, 3≦z≦13, and 0≦q≦1; - General formula Li 1-a-b-c-d P a T b A c X d (where 0 ≦ a ≦ 0.129, 0 ≦ b ≦ 0.096, 0.316 ≦ c ≦ 0.484, 0.012 ≦ d ≦ 0.125, T is an element from the group consisting of As, Si, Ge, Al, and B, X is one or more halogens or N, and A is one or more of S and Se); - A composition based on lithium (Li), boron (B), and sulfur (S), characterized by the a:b:c molar ratio of Li:B:S, where c / b is in the range of about 1 to about 3; - General formula Li n La m M’ p M’’ q Zr s O t A lithium-containing garnet having the formula, where 4 < n < 8.5, 1.5 < m < 4, 0 ≦ p ≦ 2, 0 ≦ q ≦ 2, 0 ≦ s ≦ 2.5, and 10 < t ≦ 13, and M’ and M’’ are independently selected from the group consisting of aluminum, molybdenum, tungsten, niobium, antimony, calcium, barium, strontium, cerium, hafnium, rubidium, gallium, and tantalum; - General formula Li w La v Zr k O h ·gAl2O3 (where 5 ≦ w ≦ 8, 2 ≦ v ≦ 5, 0 ≦ k ≦ 3, 10 ≦ h ≦ 13, 0 ≦ g ≦ 1); A lithium-containing garnet represented by the formula; - General formula Li j La3Zr b O 12 ·gAl2O3 (where 5 ≦ j ≦ 8, 0 < b ≦ 2.5, 0 ≦ g ≦ 1); A lithium-containing garnet represented by the formula; - General formula Li 6-3z Y z X6, (where 0 < z < 2 and X is Cl or Br); Lithium yttrium ion-conductive halide - ion-conducting polymers based on polyethylene oxide, liquid crystal polymers, polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and semi-crystalline polymers with a crystallinity of more than 30%, together with a lithium salt, preferably LiO, LiTFSI (lithium bistrifluoromethanesulfonimide), LiBOB (lithium bis(oxalate)borate) or a combination thereof; and - Polylithium acrylate and hydrophilic polymer, lithium salt, Lewis acid.

[0146] Solid separator 18 conductively connects cathode 26 and anode 16. In particular, solid separator 18 forms a protective layer between anode layer 14 of anode 16 and cathode layer 25 of cathode 26.

[0147] The solid separator 18 can have one or more layers. In particular, there can be multiple layers having different solid separators. The composition of the layers can be stepped or gradually changed.

[0148] According to one embodiment, the solid separator 18 can include a region arranged on the anode side that is more resistive to lithium metal than the region of the solid separator arranged on the cathode side. The region on the anode side preferably contains an oxidizing solid electrolyte, particularly preferably a lithium-containing garnet such as lithium lanthanum zirconate (LLZO). The lithium-ion solid-state battery 10 shown here exhibits particularly good ionic bonding between the cathode 26 and the solid separator 18. It is particularly advantageous that the first fluorine-containing polymer 22 is mechanically flexible and can adapt to the rigid, inflexible shape of the solid separator 18 and reliably compensate for volume changes.

[0149] FIG. 2 illustrates the lithium-ion solid-state battery 10 of FIG. 1 with an improved cathode 26 composition.

[0150] Cathode 26 of FIG. 2 is present as a composite and includes a cathode layer 25 that contains a mixture of cathode active material 20, a first fluorine-containing polymer 22 and a solvent component .

[0151] Additionally, the lithium ion solid state battery 10 can include the same components as described above.

[0152] In contrast to FIG. 1, the cathode of FIG.

[0153] Solvent component 28 is preferably selected from the group consisting of perfluorocarbonates, perfluoroaromatics, perfluoroethers, and combinations and derivatives thereof.

[0154] The solvent component 28 forms a gel electrolyte with the first fluorine-containing polymer. Preferably, the gel electrolyte has a gel-like consistency. Thus, the gel electrolyte is dimensionally stable, but also mechanically flexible and stretchable.

[0155] The gel-like consistency provides good ionic bonding between the cathode active material 20 and the gel electrolyte.

[0156] In addition, ionic bonds also exist between the gel electrolyte and the solid separator 18 .

[0157] Furthermore, the presence of the gel electrolyte, which has a gel-like consistency, makes it possible to compensate for the volume expansion of the cathode active material 20 during normal operation of the lithium-ion solid-state battery 10 .

[0158] FIG. 3 illustrates the lithium-ion solid-state battery 10 of FIG. 2 with different cathode 26 compositions.

[0159] Cathode 26 of FIG. 3 includes a cathode layer 25 that contains a mixture of a solvent component 28 , a cathode active material 20 , a first fluorine-containing polymer 22 and a second fluorine-containing polymer 30 .

[0160] Thus, the difference between FIG. 2 and FIG. 3 is the presence of a second fluorine-containing polymer in cathode 26.

[0161] Additionally, the lithium ion solid state battery 10 can include the same components as described above.

[0162] The second fluorine-containing polymer 30 is preferably selected from the group of sulfonated perfluoropolymers having SO3Li-containing and / or SO2C(CN)2Li-containing perfluoroalkyl side chains, preferably polytetrafluoroethylene (PTFE), such as Nafion® or polymers derived from Nafion®. Other possible side chains are SO2-N - Li + It is a -SO2CF3- containing perfluoroalkyl side chain.

[0163] Thus, the second fluorine-containing polymer 30 contains perfluorinated side chains that are saturated with lithium ions, and therefore, the second fluorine-containing polymer 30 is also a lithium ion conductor.

[0164] Preferably, the second fluorine-containing polymer 30 forms a gel with the first fluorine-containing polymer 22 and the solvent component 28 .

[0165] That is, cathode active material 20 is present in a gel consisting of first fluorine-containing polymer 22 , second fluorine-containing polymer 30 and solvent component 28 .

[0166] The gel allows for ionic bonding of the cathode active material 20 with the solid separator 18 and the cathode current collector 24 .

Claims

1. A cathode (26) for a solid-state battery (10), the cathode (26) comprising: (A) at least one cathode active material (20); (B) at least one first fluorine-containing polymer (22) having an at least partially fluorinated or perfluorinated backbone, wherein the first fluorine-containing polymer (22) is represented by the following formula (I): 【Chemistry 1】 Contains at least one ionic group of: During the ceremony, M is a cation selected from the group consisting of protons and alkali metals; n is an integer from 1 to 4; Z denotes a central ion selected from the group consisting of aluminum and boron; and R represents a monovalent, optionally fluorine-substituted hydrocarbon residue; C １ -C ８ -Alkyl, C ２ -C １０ -alkenyl, C ２ -C １０ -alkynyl, C ６ -C １２ -cycloalkyl and C ６ -C １２ - selected from the group consisting of aryl; wherein the ionic group is bonded to the backbone of the first fluorine-containing polymer (22) through at least one bridging oxygen atom of the ionic group.

2. 2. The cathode (26) of claim 1, characterized in that the hydrocarbon residue R is at least partially fluorinated, preferably fully fluorinated.

3. 3. The cathode (26) according to claim 1 or 2, characterized in that the first fluorine-containing polymer (22) comprises at least one ionic end group of general formula (I) where n=1 and / or at least one ionic crosslinking group of general formula (I) where n=2, 3 or 4.

4. 3. The cathode (26) according to claim 1 or 2, characterized in that the general formula (I) has one or more of the following characteristics: Z means aluminum; M means lithium, - R is a linear, branched or cyclic C １ -C １０ It represents a perfluoroalkyl residue, preferably a trifluoromethyl residue, particularly preferably a perfluoro-tert-butyl residue.

5. The backbone of the first fluorine-containing polymer (22) is tetrafluoroethylene (-C ２ F ４ 3. The cathode (26) of claim 1 or 2, characterized in that it comprises repeating units of the formula:

6. 3. The cathode (26) according to claim 1 or 2, characterized in that the backbone of the first fluorine-containing polymer (22) comprises at least one side chain of general formula (VII). 【Chemistry 2】 (In the formula, Y is a fluorine atom or a linear, branched or cyclic C １ -C １０ means a perfluoroalkyl residue; m is 0, 1 or 2; v is 0 or 1, Here, the ionic group of general formula (I) is a CY ２ It is attached to the backbone via the hydroxyl group residues.)

7. The cathode (26) comprises a second fluorine-containing polymer (30), which is selected from the group of sulfonated perfluoropolymers, preferably SO ３ Li-containing, SO ２ -N － Li ＋ -SO ２ CF ３ -containing and / or SO ２ C (CN) ２ 3. The cathode (26) according to claim 1 or 2, characterized in that it is selected from derivatives of polytetrafluoroethylene (PTFE) having Li-containing perfluoroalkyl side chains.

8. 3. The cathode (26) of claim 1 or 2, wherein the cathode (26) comprises at least one solvent component (28), the solvent component (28) being selected from the group consisting of perfluorocarbonates, perfluoroaromatics, perfluoroethers and perfluoroesters, and combinations and derivatives thereof, and more preferably, the solvent component (28) being capable of forming a gel with the first and / or second fluorine-containing polymers (22, 30).

9. The cathode (26) comprises the following components, in each case based on the total weight of the cathode (26): (A) 40 to 98 wt. % of at least one cathode active material (20); (B) 0.1 to 30% by weight of at least one first fluorine-containing polymer (22); (C) 0 to 30% by weight of at least one second fluorine-containing polymer, preferably selected from the group of sulfonated perfluoropolymers, preferably SO ３ Li-containing, SO ２ -N － Li ＋ -SO ２ CF ３ -containing and / or SO ２ C (CN) ２ fluorine-containing polymers selected from the group of derivatives of polytetrafluoroethylene (PTFE) having Li-containing perfluoroalkyl side chains; (D) 0 to 70% by weight, preferably 0.1 to 70% by weight, of at least one solvent component (28) consisting of perfluorocarbonates, perfluoroaromatics, perfluoroethers and perfluoroesters, and combinations and derivatives thereof; (Here, the proportions of components (A) to (D) complement each other to make up 100%) 3. A cathode (26) for a solid-state battery (10) according to claim 1 or 2, comprising:

10. 10. A solid-state battery (10) comprising: the cathode (26) of claim 1 or 2; an anode (16); and a solid separator (18) spatially separating the cathode (26) from the anode (16) and in ionically conductive contact with the cathode (26) and the anode (16), wherein the solid separator (18) comprises at least one ceramic solid electrolyte, a polymer-based solid electrolyte, a gel-based solid electrolyte, or a combination thereof.

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