Protective layer for metal electrodes and lithium battery including same

Abstract

Protective layer for metal electrodes and lithium battery including same An electrode for a lithium battery, comprising a metal layer coated with a coating layer comprising an organic binder and a metal compound selected from the group consisting of aluminum oxide, silicon dioxide, zirconium oxide, mixed oxides containing zirconium, mixed oxides containing aluminum, lithium zirconium phosphate, and mixtures thereof, wherein the metal compound has a number average primary particle size d obtained by a pyrolysis method. 50 The electrode is composed of a strong agglomerate of primary particles having a size of 5 nm to 100 nm, and the mass ratio of the metal compound to the organic binder in the coating layer is 0.1 to 10.

Description

[Technical Field]

[0001] The present invention relates to an electrode for a lithium battery containing a metal layer coated with a coating layer comprising a binder and a fumed metal compound, a method for synthesizing such an electrode, and its use in a lithium battery. [Background technology]

[0002] Various energy storage technologies have attracted considerable attention in recent years and have been the subject of intensive research and development in both industry and academia. As energy storage technologies have spread to devices such as mobile phones, camcorders, and laptops, and even electric vehicles, there has been an increasing demand for high-energy-density batteries to power such devices. Lithium-ion secondary batteries are one of the most important battery types currently in use.

[0003] Description of the Prior Art Lithium-ion secondary batteries typically consist of an anode made of carbon or silicon materials or a lithium metal alloy, a cathode made of lithium metal oxide, and an electrolyte consisting of a lithium salt dissolved in an organic solvent. The separator in a lithium-ion battery provides a pathway for lithium ions between the positive and negative electrodes during the charge and discharge process.

[0004] Lithium metal batteries (LMBs), such as lithium-sulfur (Li-S) batteries, lithium-air (Li-air) batteries, and solid-state lithium batteries, have been reported to overcome at least some of the limitations of lithium-ion batteries, such as the lack of high energy storage capacity. However, the inherent properties of metallic Li raise several safety and device instability issues, leading to limited cycle life. The highly reactive nature of Li causes various processes that generally have a detrimental effect on battery cycle life, such as degradation of the liquid electrolyte, formation of a solid-electrolyte interface (SEI), corrosion of the Li anode due to the presence of trace amounts of water in the electrolyte, formation of Li dendrites, and passivation of Li through the polysulfide shuttle effect in Li-S batteries. Therefore, successful stabilization / protection of the Li anode is essential for the practical development of LMB technology.

[0005] Recently, several approaches have been pursued to stabilize the lithium metal / electrolyte interface, including coatings of soft polymers that have shown the ability to enable high-rate and high-capacity cycling of lithium metal.

[0006] Thus, a controlled protection of the Li anode with organic and / or inorganic materials is disclosed that beneficially affects the battery performance.

[0007] Chinese Patent Publication No. 109473627 (CN109473627A) describes the preparation of a composite electrode comprising lithium metal, an inorganic nanomaterial, such as titanium oxide, alumina, silica, boehmite, or zirconia, with a particle size of 50-500 nm, an organic polymer, and a membrane material, by the following steps: (1) preparing a solution of polymer and inorganic particles; (2) coating the solution on the surface of a membrane followed by drying; (3) crushing the dried composite material prepared in step (2) with metallic lithium to form composite electrode particles coated with a composite layer; and (4) shaping the composite electrode material to form a metallic lithium electrode sheet comprising lithium particles coated with a protective layer.

[0008] US Patent Application Publication No. 2017 / 0062829 (US20170062829 A1) discloses a lithium metal battery including a lithium metal anode having a protective layer containing a polymer, such as a styrene-isoprene copolymer, at least one metal salt, and a nitrogen-containing additive, such as Li3N. The protective layer can also contain inorganic particles, such as TiO2, ZnO, Al2O3, or SiO2, having a particle size of about 1 to 500 nm, but is not further specified.

[0009] US Patent Application Publication No. 2014 / 0220439 (US20140220439 A1) discloses an alkali metal electrode coated with a protective coating comprising inorganic particles, such as the elements Al, Mg, Fe, Sn, Si, B, Cd, and Sb, dispersed throughout a matrix of an organic compound, such as a pyrrolidine derivative.

[0010] US Patent Application Publication No. 2017 / 0301920 (US20170301920 A1) describes a method for preparing a polymeric ionic liquid, optionally containing inorganic nanoparticles, such as SiO 2、 They disclose lithium metal electrodes coated with protective layers including Al2O3, TiO2, MgO, ZrO2, ZnO, Fe3O4, barium titanate, lead titanate, lithium nitride, and lithium aluminate.

[0011] Jang et al. described the fabrication of coated lithium metal anodes in Adv. Funct. Mater. 2019, vol. 29(48), No. 1905078. Thus, ZrO powder with a particle size of 5 μm or AlO powder with an average particle size of 500 nm was mixed with poly(vinylidene fluoride-co-hexafluoropropylene) (PDdF-HFP) polymer, DMF, and electrolyte, and the slurry was subsequently coated onto a 450 μm-thick lithium metal foil and dried to form a 21.7 μm-thick coating layer.

[0012] International Publication No. 2019 / 149939 (WO2019149939 A1) discloses a lithium metal anode coated with a protective layer having a thickness of 0.01 to 10 μm and consisting of a polymer and up to 30% by weight, relative to the polymer, of inorganic particles such as Al2O3, MnO, MnO2, SiO2, TiO2, ZnO, ZrO2, Fe2O3, CuO, silicates, aluminosilicates, and borosilicates, with an average particle size of 1 to 500 nm.

[0013] Lee, Y., Fujiki, S., Jung, C. et al., in Nature Energy, volume 5, pp. 299-308 (2020), describe a high-performance all-solid-state lithium metal battery with a sulfide electrolyte and an Ag-C composite anode without excess lithium. The metal layer of the composite Ag-C anode in this system can effectively control Li deposition, which leads to extended electrochemical cyclability. Therefore, in this case, instead of using a classical lithium anode, a silver-based anode is used, on which a lithium layer is reversibly deposited during the operation of the lithium battery.

[0014] Problems and Solutions It is commonly known that lithium electrodes in lithium batteries are protected with polymers and various inorganic particles, such as metal oxides, to improve the cycling behavior of the battery. However, specific examples of such coatings typically contain relatively large inorganic particles and relatively low content of such inorganic particles in the coating. While several publications generally relate to nanostructured inorganic particles having particle sizes between 100 and 500 nm, they often do not provide further details, such as the manufacturing methods or source materials for such particles. In most cases, information on whether the inorganic particles are strongly or weakly agglomerated is also not provided.

[0015] Importantly, the physicochemical properties of such protective inorganic particles, such as the type of particle, their particle size, particle size distribution, agglomeration and agglomeration, and the content of such particles used to protect the electrode are of utmost importance for providing chemical stability of the metallic lithium electrode during cycling of the lithium battery.

[0016] Therefore, practical methods for improving the long-term life of batteries are often limited. Thus, in the case of metal oxides, the use of commercially available nano-sized particles often results in non-uniform distribution and large, weakly agglomerated particles on the surface of the lithium electrode, resulting in minimal or no observed improvement in cycling performance compared to uncoated electrodes. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Chinese Patent Application Publication No. 109473627 [Patent Document 2] US Patent Application Publication No. 2017 / 0062829 [Patent Document 3] US Patent Application Publication No. 2014 / 0220439 [Patent Document 4] U.S. Patent Application Publication No. 2017 / 0301920 [Patent Document 5] International Publication No. 2019 / 149939 [Non-patent literature]

[0018] [Non-Patent Document 1] Jang et al., Adv.Funct.Mater. 2019, vol.29(48), No.1905078 [Non-patent document 2] Lee, Y., Fujiki, S., Jung, C. et al., Nature Energy, volume 5, pages 299~308 (2020) Summary of the Invention [Problem to be solved by the invention]

[0019] The problem addressed by the present invention is to provide modified metal electrodes for lithium batteries, and in particular for lithium metal batteries, which should offer higher cycling stability than unmodified materials. [Means for solving the problem]

[0020] In the course of extensive experimentation, it was unexpectedly found that the combination of an organic binder with selected metal compounds produced by pyrogenic methods may be particularly suitable for coating metal electrodes, such as lithium electrodes, for lithium-ion batteries.

[0021] The present invention provides an electrode for a lithium battery, comprising a metal layer coated with a coating layer comprising an organic binder and a metal compound selected from the group consisting of aluminum oxide, silicon dioxide, zirconium oxide, mixed oxides containing zirconium, mixed oxides containing aluminum, lithium zirconium phosphate, and mixtures thereof, wherein the metal compound has a number average primary particle size d obtained by a pyrolysis method. 50The electrode is made of a strong agglomerate of primary particles having a size of 5 nm to 100 nm, and the mass ratio of the metal compound to the organic binder in the coating layer is 0.1 to 10.

[0022] The metal compounds of the present invention can be obtained by pyrolysis (also known as "fume" or "fumed") processes. Pyrolysis (fume) processes include, for example, flame oxidation, flame hydrolysis, or flame pyrolysis. Such processes involve the oxidation or hydrolysis of hydrolyzable or oxidizable starting materials, typically in a hydrogen / oxygen flame. Starting materials used for pyrolysis processes include organic and / or inorganic metal compounds, such as metal chlorides, metal nitrates, and metal carboxylates. In flame hydrolysis, for example, metal precursors, such as metal chlorides, are typically vaporized and reacted in a flame generated by the reaction of hydrogen and oxygen to form metal compound particles. The resulting powders are referred to as "pyrolyzed" or "fumed" metal compounds. The reaction initially forms highly dispersed primary particles, which, during further reaction, coalesce to form agglomerates, i.e., strongly bonded primary particles, and agglomerates, i.e., relatively weakly bonded agglomerates. The size of the agglomerates in these powders typically ranges from 0.2 μm to 2 μm. The powders can be partially broken down by suitable crushing and converted into particles in the nanometer (nm) range, which is advantageous for the present invention. Metal compounds produced by pyrogenic methods are characterized by extremely small particle size, high specific surface area (BET), very high purity, spherical primary particles, and the absence of pores. The preparation of fumed alumina by flame hydrolysis is described in detail, for example, in German Patent Application No. 19943291 (DE19943291 A1).

[0023] The metal compound used in the present invention preferably has a specific surface area (BET) of 0.1 m 2 / g~400m 2 The non-heat treated metal compounds, i.e. the products of pyrolysis processes where no further heat treatment is used, preferably have a BET surface area of 5 m 2 / g~300m 2 / g, more preferably 7m 2 / g~200m 2 / g, most preferably 15 to 150m 2 Heat-treated metal compounds, i.e., products of pyrolysis processes where a further heat treatment, e.g., a calcination step, has been used, preferably have a BET surface area of 10 m 2 / g, more preferably less than 0.1m 2 / g~10m 2 / g, more preferably 0.2m 2 / g~5m 2 / g, most preferably 0.3 to 3m 2 The specific surface area (also simply referred to as the BET surface area) can be determined by nitrogen adsorption according to the Brunauer-Emmett-Teller method in accordance with DIN 9277:2014.

[0024] The zirconium-containing mixed oxides present in the electrode of the present invention may further comprise, besides zirconium metal, one or more elements M selected from the group consisting of Li, Na, K, Be, Mg, Ca, Sr, Ba, Zn, Co, Ni, Cu, Mn, B, Al, Ga, In, Fe, Sc, Y, La, Ti, Zr, Hf, Ce, Si, Ge, Sn, Pb, V, Nb, Ta, Mo, W. Silicon (Si) and boron (B) are considered to be metals in the context of the present invention.

[0025] Preferably, M=Li, La and / or Al.

[0026] The zirconium-containing mixed oxide is preferably represented by the general formula Li a Zr b M c O 0.5a+2b+d (I) [In the formula, 1.5≦a≦15, 0.5≦b≦3.0, 0≦c≦5, When M=Na or K, d=0.5c. When M=Be, Mg, Ca, Sr, Ba, Zn, Co, Ni, Cu, Mn, d=c. When M=B, Al, Ga, In, Fe, Sc, Y, or La, d=1.5c. When M=Ti, Zr, Hf, Ce, Si, Ge, Sn, Pb, d=2c. For M=V, Nb, Ta, d=2.5c, For M=Mo, d=3c for W] is a compound of

[0027] The aluminum-containing mixed oxide may be lithium aluminate (LiAlO2) or any other mixed oxide containing lithium, aluminum and oxygen.

[0028] The lithium zirconium phosphate produced preferably has the general formula Li a Zr b M c (PO4) d [In the formula, M is at least one metal different from Li and Zr; 0.5≦a≦5.0, 0.5≦b≦5.0, 0≦c≦5, 1≦d≦5] is a compound of

[0029] The metal compounds used in the electrodes according to the present invention are in the form of strongly agglomerated primary particles having a number-average primary particle size of 5 to 100 nm, preferably 7 to 70 nm, more preferably 10 to 50 nm, as determined by transmission electron microscopy (TEM). This number-average diameter can be determined by calculating the average size of at least 500 particles analyzed by TEM.

[0030] The particles of the metal compound used in the present invention obtained by the pyrolysis method are usually mostly in the form of agglomerates, but some particles may be in the form of non-agglomerated primary particles. The metal compound preferably has a number average particle size d 50The number average particle size d is less than 2 μm, more preferably 20 nm to 1 μm, more preferably 30 nm to 800 nm, more preferably 40 nm to 600 nm, or 50 nm to 500 nm. 50 can be determined in a suitable dispersion, for example an aqueous dispersion, by static light scattering (SLS) techniques.

[0031] The weak aggregates and partially the strong aggregates can be disrupted, for example, by crushing or sonicating the particles, resulting in particles with smaller particle sizes and narrower particle size distributions.

[0032] Preferably, the number average particle size d of the agglomerates of the metal compound 50 is 5 nm to 250 nm, more preferably 10 nm to 200 nm, and even more preferably 15 nm to 150 nm, as determined by static light scattering (SLS) after ultrasonic treatment of a mixture consisting of 5 mass % of the particles and 95 mass % of a 0.5 g / L aqueous sodium pyrophosphate solution at 25°C for 300 seconds.

[0033] The span (d 90 -d 10 ) / d 50 is preferably 0.4 to 1.2, more preferably 0.5 to 1.1, and even more preferably 0.6 to 1.0, as determined by static light scattering (SLS) after ultrasonic treatment of a mixture consisting of 5 mass % of the particles and 95 mass % of a 0.5 g / L aqueous sodium pyrophosphate solution at 25°C for 300 seconds.

[0034] Therefore, the metal compounds present in the electrodes of the present invention preferably have a relatively small number average particle size d of agglomerates. 50 and narrow particle size distribution (d 90 -d 10 ) / d 50 This helps to achieve high quality metal compound coating on the lithium electrode.

[0035] d of d value 10 , d 50 and d 90is commonly used to evaluate the cumulative particle size distribution of a given sample. For example, d 10 The diameter is d 10 is the diameter of the smaller particles, and d 50 is 50% of the sample volume 50 is the diameter of the smaller particles. 50 is also known as the "volume median diameter" because it divides the sample equally by volume, and d 90 is the volume of the sample that is 90% of the 90 diameter consisting of particles smaller than

[0036] The tamped density of the metal compound present in the electrode of the present invention may be 20 g / L to 1000 g / L. The non-heat-treated metal compound preferably has a tamped density of 20 g / L to 200 g / L, more preferably 30 g / L to 150 g / L, even more preferably 40 g / L to 130 g / L, and even more preferably 50 g / L to 120 g / L. The heat-treated, e.g., calcined, metal compound preferably has a tamped density of 400 g / L to 1000 g / L, more preferably 450 g / L to 800 g / L, and even more preferably 500 g / L to 700 g / L. The tamped density of fine or coarse granular materials can be determined in accordance with DIN ISO 787-11:1995 "General methods of test for pigments and extenders - Part 11: Determination of tamped volume and apparent density after tamping." This involves measuring the bulk density of the bed after mixing and tamping.

[0037] The metal compounds used in the electrodes of the present invention are preferably hydrophilic in nature, i.e., they are not further treated with hydrophobic reagents, such as silanes, after their synthesis by pyrolysis. The particles thus produced typically have a purity of at least 96% by weight, preferably at least 98% by weight, and more preferably at least 99% by weight, where 100% purity means that the metal compound contains only the necessary elements in the proportions corresponding to the chemical formula of the metal compound used. The chloride content is preferably less than 0.5% by weight, more preferably less than 0.1% by weight, based on the weight of the metal compound powder. The carbon content is preferably less than 2.0% by weight, more preferably 0.005% to 1.0% by weight, and even more preferably 0.01% to 0.5% by weight, based on the weight of the metal compound powder.

[0038] Surface-treated metal compounds The metal compounds present in the electrodes according to the invention may be surface-treated, and this surface treatment, in particular a hydrophobic surface treatment, can improve the compatibility of the metal compound particles with the organic binder.

[0039] The metal compound present in the electrode of the present invention may be hydrophobic and have a methanol wettability in a mixture of methanol and water of more than 5% by volume, preferably 10% to 80% by volume, more preferably 15% to 70% by volume, particularly preferably 20% to 65% by volume, and most preferably 25% to 60% by volume of methanol content.

[0040] The terms "hydrophobic" or "hydrophobized" in the context of the present invention refer to particles with a low affinity for polar media, such as water. In contrast, hydrophilic particles have a high affinity for polar media, such as water. The hydrophobicity of hydrophobic materials can typically be achieved by applying appropriate nonpolar groups to the particle surface. The degree of hydrophobicity of a metal compound can be determined through parameters including its methanol wettability, as described in detail, for example, on pages 5-6 of International Publication No. WO 2011 / 076518 A1. In pure water, hydrophobic particles of a metal compound completely separate from water and float on their surface without being wetted by the solvent. In contrast, in pure methanol, the hydrophobic particles are distributed throughout the solvent volume, resulting in complete wetting. In measuring methanol wettability, the maximum methanol content in a test mixture of methanol and water at which the metal compound remains unwetted is determined, meaning that 100% of the metal compound used remains separated from the test mixture in an unwetted form after contact with the test mixture. This methanol content by volume % in a mixture of methanol and water is referred to as the methanol wettability. The higher the level of such methanol wettability, the more hydrophobic the metal compound. The lower the methanol wettability, the less hydrophobic and more hydrophilic the material.

[0041] The metal compounds of the present invention may be surface treated, e.g., hydrophobized, with a surface treatment agent selected from the group consisting of organosilanes, silazanes, acyclic polysiloxanes, cyclic polysiloxanes, and mixtures thereof.

[0042] The hydrophobic metal compound preferably has a carbon content of 0.1% to 15.0% by weight, more preferably 0.5% to 10.0% by weight, and more preferably 1.0% to 5.0% by weight. The carbon content can be determined by elemental analysis according to EN ISO 3262-20:2000 (Chapter 8). The analytical sample is weighed and placed in a ceramic crucible, which is supplied with a combustion additive and heated in an induction furnace under oxygen flow. The carbon present is oxidized to CO2. The amount of CO2 gas is quantified by an infrared detector.

[0043] metal layer In the context of the present invention, the term "layer" means a continuous deposit of a corresponding substance or component on the surface of another substance or component.

[0044] The metal layer of the electrode of the present invention, e.g., a lithium layer, can be further supported on a metal foil that serves as a current collector. The metal foil can include lithium, aluminum, copper, silver, gold, nickel, iron, steel, stainless steel, titanium, or a metal alloy thereof. Such metal alloys can also include non-metallic components, such as silicon and germanium. Most preferably, the metal foil is made of copper, especially when the electrode of the present invention is used in combination with a liquid electrolyte. Stainless steel foil is preferably used in electrodes used in combination with a solid electrolyte, e.g., a sulfide-based electrolyte. Such metal foils can have a thickness of 0.5 μm to 500 μm, more preferably 1 μm to 100 μm, and more preferably 5 μm to 30 μm. The metal foil can be further supported on a polymer substrate.

[0045] The electrode according to the present invention preferably comprises a layer of metal having a thickness of 2 μm to 500 μm, more preferably 3 μm to 300 μm, more preferably 5 μm to 200 μm.

[0046] The metal layer may be coated onto the metal foil by any suitable method, for example, vacuum deposition.

[0047] Covering layer The coating layer present in the electrode of the present invention comprises an organic binder and a metal compound selected from the group consisting of aluminum oxide, zirconium oxide, mixed oxides containing zirconium, mixed oxides containing aluminum, lithium zirconium phosphate, and mixtures thereof.

[0048] The mass ratio of the metal compound to the organic binder in the coating layer is 0.1 to 10, preferably 0.2 to 9.5, more preferably 0.3 to 9.0, more preferably 0.4 to 8.5, more preferably 0.5 to 8.0, more preferably 0.8 to 7.0, and more preferably 1.0 to 6.0.

[0049] The electrode of the present invention may optionally contain a lithium salt added to the coating layer. The lithium salt may be selected from the group consisting of lithium hexafluorophosphate (LiPF), lithium bis(2-(trifluoromethylsulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO), lithium tetrafluoroborate (LiBF), LiSiF, lithium triflate, lithium bis(perfluoroethylsulfonyl)imide (LiN(SOCFCF)), lithium nitrate, lithium bis(oxalato)borate, lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide, lithium cyclohexafluoropropane-1,1-bis(sulfonyl)imide, and mixtures thereof. Lithium bis(fluorosulfonyl)imide (LiFSI) is preferably used as the lithium salt in the coating layer combined with the solid electrolyte.

[0050] The thickness of the coating layer may be 0.1 μm to 300 μm, more preferably 0.5 μm to 100 μm, more preferably 1 μm to 50 μm, and more preferably 5 μm to 20 μm.

[0051] organic binder The coating layer of the electrode of the present invention contains an organic binder. The material of the organic binder is not particularly limited, as long as it allows effective adhesion between the metal compound particles and the surface of the lithium layer. The binder may be selected from the group consisting of poly(vinylidene fluoride), copolymers of vinylidene fluoride and hexafluoropropylene, poly(vinyl acetate), poly(ethylene oxide), poly(methyl methacrylate), poly(ethyl acrylate), poly(vinyl chloride), poly(urethane), poly(acrylonitrile), poly(ethylene glycol) and poly(ethylene glycol)-dimethyl ether, poly(ether amine), copolymers of ethylene and vinyl acetate, carboxymethyl cellulose, poly(imide), and mixtures thereof.

[0052] Electrode manufacturing method The present invention further provides a method for producing an electrode of the present invention, comprising the steps of: (1) an organic binder; a metal compound selected from the group consisting of aluminum oxide, silicon dioxide, zirconium oxide, mixed oxides containing zirconium, mixed oxides containing aluminum, lithium zirconium phosphate, and mixtures thereof; optionally a lithium salt selected from the group consisting of lithium hexafluorophosphate (LiPF), lithium bis-2-(trifluoromethylsulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO), lithium tetrafluoroborate (LiBF), LiSiF, lithium triflate, lithium bis(perfluoroethylsulfonyl)imide (LiN(SOCFCF)), lithium nitrate, lithium bis(oxalato)borate, lithium-cyclo-difluoromethane-1,1-bis(sulfonyl)imide, lithium-cyclo-hexafluoropropane-1,1-bis(sulfonyl)imide, and mixtures thereof; Optionally, a solvent and forming a mixture comprising the metal compound having a number average primary particle size d 50the step of forming a strong agglomerate of primary particles having a size of 5 nm to 100 nm and obtained by a pyrolysis method, wherein the mass ratio of the metal compound to the organic binder is 0.1 to 10, preferably 0.2 to 9.5, more preferably 0.3 to 9.0, more preferably 0.4 to 8.5, more preferably 0.5 to 8.0, more preferably 0.8 to 7.5, more preferably 1.0 to 6.0; (2) coating the mixture prepared in step (1) onto the surface of the metal layer; (3) optionally drying and / or curing the coating layer produced in step (2). The method includes:

[0053] The solvent optionally used in step (1) of the method of the present invention is not particularly limited, so long as it can dissolve the binder and does not react with lithium metal during the coating process. Non-exhaustive examples of suitable solvents include 1,2-dimethoxyethane, diethyl ether, tetrahydrofuran, dioxane, bis(2-methoxyethyl)ether, pentane, hexane, heptane, octane, decane, toluene, ethanol, isopropanol, N-methyl-2-pyrrolidone, triethyl phosphate, dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone, benzaldehyde, N,N-dimethylformamide, dimethylacetamide, acetonitrile, cyclohexanone, ethyl acetate, propylene carbonate, ethylene carbonate, diethylene glycol monomethyl ether, triethylene glycol methyl ether, acetylacetone, acetone, and mixtures thereof.

[0054] The mixture produced in step (1) of the method according to the invention can be obtained from two or more mixtures, for example a first mixture comprising metal compound particles and a solvent and a second mixture comprising an organic binder, a solvent, and optionally a lithium salt.

[0055] Preferably, such a first mixture contains 1% by mass to 70% by mass, preferably 10% by mass to 60% by mass, more preferably 20% by mass to 50% by mass, more preferably 30% by mass to 45% by mass of a metal compound, and 30% by mass to 99% by mass, preferably 40% by mass to 90% by mass, more preferably 50% by mass to 80% by mass, more preferably 55% by mass to 70% by mass of a solvent.

[0056] The second mixture may comprise 0.1% to 90% by weight, preferably 0.5% to 50% by weight, more preferably 1% to 20% by weight, more preferably 2% to 10% by weight of an organic binder, and 10% to 99.9% by weight, preferably 50% to 99.5% by weight, more preferably 80% to 99% by weight, more preferably 90% to 98% by weight of a solvent.

[0057] In step (2) of the method of the present invention, a metal layer is coated with the mixture prepared in step (1), to form a coating layer containing a metal compound and an organic binder on the surface of the metal layer. Any suitable coating method that allows the application of a relatively thin coating layer can be applied. An example of a suitable device for the coating step is a doctor blade tool SA-202 (manufacturer: Tester Industries).

[0058] The mixture coated onto the metal layer in step (2) is optionally further dried and / or cured on the surface of said metal layer in step (3) of the method of the present invention, leading to the formation of the coated metal electrode of the present invention.

[0059] Curing of the coating mixture can occur, for example, by polymerization, crosslinking, or other types of chemical reaction, or by physical curing due to evaporation of solvents or other volatile components of the binder. Chemical curing can occur, for example, thermally or under the action of UV or other radiation.

[0060] Depending on the system used, step (3) can be carried out at temperatures preferably between 0°C and 500°C, more preferably between 5°C and 400°C, more preferably between 10°C and 300°C, more preferably between 20°C and 150°C. The drying / curing step can be carried out in the presence of air or, preferably with the exclusion of oxygen, under a protective gas atmosphere, for example nitrogen or argon. Said step can be carried out under normal pressure or under reduced pressure, for example under vacuum.

[0061] Use of electrodes The present invention further provides the use of an electrode of the present invention as a component of a lithium metal or lithium ion battery, preferably a lithium metal battery.

[0062] battery The present invention further provides a battery comprising an electrode according to the present invention, which electrode typically functions as the anode in such a battery.

[0063] The battery may be a lithium ion battery and may further include a separator or solid electrolyte, a cathode, an anode, and / or an electrolyte including a lithium salt.

[0064] The cathode of a lithium-ion battery typically includes a current collector and a cathode active material layer formed on the current collector.

[0065] The current collector may be lithium foil, copper foil, nickel foil, aluminum foil, iron foil, steel foil, stainless steel foil, titanium foil, metal alloy foil, a polymer substrate coated with a conductive metal, or a mixture thereof.

[0066] Cathode active materials include materials capable of reversibly inserting and extracting lithium ions and are well known in the art. Such cathode active materials can include lithium metal, lithium alloys, sulfur, lithium sulfide, silicon, silicon oxide, silicon carbide composites, silicon alloys, Sn, SnO, or transition metal compounds, such as mixed oxides containing Li, Ni, Co, Mn, Fe, P, Al, V, or other transition metals.

[0067] The liquid electrolyte of a lithium ion battery can include any organic solvent commonly used in lithium ion batteries, such as anhydrous ethylene carbonate (EC), dimethyl carbonate (DMC), propylene carbonate, ethyl methyl carbonate, diethyl carbonate, γ-butyrolactone, dimethoxyethane, fluoroethylene carbonate, vinylethylene carbonate, or mixtures thereof.

[0068] The electrolyte of a lithium-ion battery typically contains a lithium salt, examples of which include lithium hexafluorophosphate (LiPF), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO), lithium tetrafluoroborate (LiBF), LiSiF, lithium triflate, LiN(SOCFCF), and mixtures thereof.

[0069] Lithium-ion batteries can contain liquid, gel, or solid electrolytes. In the context of the present invention, a liquid mixture of a lithium salt and an organic solvent that has not been cured, polymerized, or crosslinked is referred to as a "liquid electrolyte." A gel or solid mixture containing a cured, polymerized, or crosslinked compound or mixture thereof, optionally a solvent, and a lithium salt is referred to as a "gel electrolyte." Such gel electrolytes can be made by polymerization or crosslinking of a mixture containing at least one reactive, i.e., polymerizable, or crosslinkable, compound and a lithium salt.

[0070] A special type of lithium-ion battery is the lithium polymer battery, in which a polymer electrolyte is used instead of a liquid electrolyte. The electrolyte in similar solid-state batteries can also include other types of solid electrolytes, such as sulfide-based solid electrolytes, oxide-based solid electrolytes, or mixtures thereof.

[0071] The batteries of the present invention may be lithium metal batteries, such as Li-air, lithium-sulfur (Li-S), and other types of lithium metal batteries.

[0072] Lithium-air batteries typically contain a porous carbon cathode and electrodes of the organic, glass-ceramic, or polymer-ceramic type.

[0073] Li-sulfur (Li-S) batteries typically contain cathodes of iron disulfide (FeS2), iron sulfide (FeS), copper sulfide (CuS), lead sulfide, and copper sulfide (PbS+CuS).

[0074] Many other known types of lithium metal batteries exist, such as lithium-selenium (Li-Se), lithium-manganese dioxide (Li-MnO or Li / Al-MnO), lithium-monofluoride (Li-(CF) x ), lithium-thionyl chloride (Li-SOCl2), lithium-sulfuryl chloride (Li-SO2Cl2), lithium-sulfur dioxide (Li-SO2), lithium-iodine (Li-I2), lithium-silver chromate (Li-Ag2CrO4), lithium-vanadium pentoxide (Li-V2O5 or Li / Al-V2O5), lithium-copper chloride (Li-CuCl2), lithium-copper(II) oxide (Li-CuO), lithium-copper oxyphosphate (Li-Cu4O(PO4)2), and other types are also available. [Brief explanation of the drawings]

[0075] [Figure 1a] Figure 1a shows the polarization voltage for various metal compounds at a current density of 0.1 mA / cm2 in liquid electrolyte. [Figure 1b] Figure 1b shows the polarization voltage for various metal compounds at a current density of 0.5 mA / cm2 in liquid electrolyte. [Figure 1c] Figure 1c shows the polarization voltages for materials from Examples 12a–14a at current densities of 0.05 (cycles 1–5)–0.1 (cycles 5–9) mA / cm 2 in the hybrid solid electrolyte. [Figure 1d] Figure 1d shows the polarization voltages for materials from Examples 12a–14a at current densities of 0.25 (cycles 1–5)–0.5 (cycles 5–9) mA / cm 2 in the hybrid solid electrolyte. [Figure 2A] FIG. 2(A) shows the plating and stripping cycle for Example 6a. [Figure 2B] FIG. 2(B) shows the plating and stripping cycle for Example 5a. [Figure 2C] FIG. 2(C) shows the plating and stripping cycle for Example 4a. [Figure 3] Figure 3 shows the cycle characteristics of the Li-Cu asymmetric cell. [Figure 4A] FIG. 4(A) shows an SEM image for the electrode from Example 8b, showing the volume expansion of the electrode compared to a reference without an alumina-polymer coating (reference value 100%). [Figure 4B] FIG. 4(B) shows an SEM image for the electrode from Example 7b, showing the volume expansion of the electrode compared to a reference without an alumina-polymer coating (reference value 100%). [Figure 4C] FIG. 4(C) shows an SEM image for the electrode from Example 4b, showing the volume expansion of the electrode compared to a reference without an alumina-polymer coating (reference value 100%). [Example]

[0076] Metal compound samples AEROXIDE Alu 130 is supplied by Evonik Operations GmbH with a BET of 130m 2 / g.

[0077] TAMICON® TM-DAR (hereinafter referred to as "TM-DAR") is a cellulose ester copolymer with a BET of 14.5 m3 supplied by Taimei Chemical Industry Co., Ltd. 2 / g.

[0078] BET=3.9m supplied by US Research Nanomaterials, Inc. 2 / g is referred to below as "USR".

[0079] Evonik ZrO2 is supplied by Evonik Operation GmbH. BET=40m 2 / g of fumed zirconium oxide.

[0080] The LLZO precursor particles were BET ca. 28m supplied by Evonik Operation GmbH. 2 fumed aluminum-doped lithium lanthanum zirconium oxide particles having a saturation of 1 / g.

[0081] Cubic LLZO particles were obtained using BET approx. 0.4 m2 supplied by Evonik Operation GmbH. 2 fumed and calcined aluminum-doped lithium lanthanum zirconium oxide particles having a SiO 2 content of 1000 ppm or less.

[0082] Evonik Ball Mill (BM) c-LLZO (hereinafter referred to as "BM c-LLZO") is a ball mill with a BET of approximately 10 m 2 1. Fumed, calcined and ball milled aluminum doped lithium lanthanum zirconium oxide particles having a SiO2 content of 1000 ppm or less.

[0083] NEI LLZO (hereinafter referred to as "NEI LLZO") is a BET approximately 4.8 m² supplied by NEI Corporation. 2 It is a cubic aluminum-doped lithium lanthanum zirconium oxide having a crystallinity of 0.1 / g.

[0084] The physical properties of the metal compound particles tested are summarized in Table 1.

[0085] [Table 1]

[0086] Preparation of coated electrode sheets Example 1a A 12 μm-thick copper foil coated with a 100 μm-thick lithium metal layer was prepared. AEROXIDE® Alu 130 particles were dispersed in 1,2-dimethoxyethane (DME) to obtain a first solution with a solids content of 40% by weight. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) (supplied by Sigma-Aldrich, weight average molecular weight (Mw) approximately 400,000 g / mol) was also dissolved in DME to obtain a second solution with a solids content of 5% by weight. Both the first and second solutions were vigorously stirred for several hours and then mixed together under stirring in a ratio such that a mixture with a 1:1 alumina to PVDF-HFP polymer (by weight) was produced. This mixture was coated onto the lithium metal layer by solvent casting: the raw mixture slurry was stirred with a magnetic stirrer in a 20 ml sample vial, followed by coating in one go with a pen brush. After heating on a hot plate at 70 °C for 30 min, an electrode sheet with an artificial solid electrolyte interface (ASEI) layer with a thickness of approximately 10 μm was obtained.

[0087] Example 1b As described in Example 1a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0088] Example 2a As described in Example 1a, except that the electrode sheet was coated using a mixture containing a 1:1 (by mass) mixture of alumina particles TM-DAR and PVDF-HFP.

[0089] Example 2b As described in Example 2a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0090] Example 3a As described in Example 1a, except that the electrode sheet was coated using a mixture containing a 1:1 (by mass) mixture of alumina particles USR and PVDF-HFP.

[0091] Example 3b As described in Example 3a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0092] Example 4a As described in Example 1a, except that the electrode sheet was coated using a mixture comprising a 4:1 (by mass) mixture of alumina particles AEROXIDE® Alu130 and PVDF-HFP.

[0093] Example 4b As described in Example 4a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0094] Example 5a As described in Example 1a, except that the electrode sheet was coated using a mixture containing a 4:1 (by mass) mixture of alumina particles TM-DAR and PVDF-HFP.

[0095] Example 5b As described in Example 5a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0096] Example 6a As described in Example 1a, except that the electrode sheet was coated using a mixture containing a 4:1 (by mass) mixture of alumina particles USR and PVDF-HFP.

[0097] Example 6b As described in Example 6a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0098] Example 7a As described in Example 1a, except that the electrode sheet was coated using a mixture containing a 6:1 (by mass) mixture of alumina particles TM-DAR and PVDF-HFP.

[0099] Example 7b As described in Example 7a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0100] Example 8a As described in Example 1a, except that the electrode sheet was coated using a mixture containing a 6:1 (by mass) mixture of alumina particles USR and PVDF-HFP.

[0101] Example 8b As described in Example 8a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0102] Example 9a As described in Example 4a, except that the electrode sheet was coated using a mixture containing a 4:1 (by weight) mixture of ZrO2 particles and PVDF-HFP.

[0103] Example 10a As described in Example 4a, except that the electrode sheet was coated using a mixture comprising a 4:1 (by weight) mixture of Evonik LLZO precursor particles and PVDF-HFP.

[0104] Example 10b As described in Example 10a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0105] Example 11a As described in Example 4a, except that the electrode sheet was coated using a mixture comprising a 6:1 (by weight) mixture of NEI LLZO and PVDF-HFP.

[0106] Example 11b As described in Example 11a, except that copper foil without a lithium metal layer was used as the electrode sheet instead of lithium-deposited copper foil, and acetone was used as the solvent instead of 1,2-dimethoxyethane (DME) to disperse the oxide particles and dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for the coating formulation.

[0107] Example 12a A copper foil (10 μm thick) with a lithium metal layer (100 μm thick) was prepared. PVDF-HFP was dissolved in DME to obtain a first solution (5 wt % solids content). AEROXIDE® Alu 130 (alumina particles) was dispersed in the first solution (50 wt % alumina particles and 50 wt % PVDF-HFP) (the mixture was vigorously stirred for several hours) to obtain a first slurry (9.5 wt % solids content). The mixture was applied to the lithium metal layer by solvent casting using a brush. After baking on a hot plate at 70 °C for 30 minutes to remove the DME, both electrodes were covered with a hybrid solid electrolyte film (details are described in the section on fabricating a Li-Li symmetric cell in a solid (hybrid) polymer electrolyte) to assemble a coin cell.

[0108] Example 13a As described in Example 12a, except that lithium bis(fluorosulfonyl)imide (LiFSI, supplied by Kishida Chemical Co., Ltd.) was dissolved in the second slurry and stirring was continued for 1 minute. The mixture was dropped onto the lithium metal layer and then covered with a hybrid solid electrolyte membrane. The mixture was also dropped onto the other side of the membrane and then quickly covered with another lithium metal electrode.

[0109] Example 14a Both lithium metal electrodes without protective layers were covered by a hybrid solid electrolyte film (details are described in Fabrication of Li-Li Symmetric Cell in Solid (Hybrid) Polymer Electrolyte) to assemble a coin cell.

[0110] The mass ratios of metal compound particles to PVDF-HFP used in Examples 1a, b to 14a, b are summarized in Tables 2-1 and 2-2.

[0111] [Table 2-1]

[0112] [Table 2-2]

[0113] Fabrication of Li-Li symmetric cells in liquid electrolyte A solution of 1 M lithium bis(trifluoromethanesulfonyl)imide (supplied by Kishida, >99.9%) containing 1% by weight lithium nitrate (supplied by Sigma-Aldrich, stored in a glove box for 1 week) in a 1:1 (vol / vol) mixture of 1,3-dioxolane (supplied by Sigma-Aldrich, 99.8%) and 1,2-dimethoxyethane (supplied by Kishida, 99.9%) was used as the electrolyte composition. The first coated electrode sheet, a polypropylene-polyethylene-polypropylene (PP / PE / PP) separator (Celgard® 2320, supplied by Celgard) with a thickness of approximately 10–20 μm, and a second (identical) electrode sheet were sequentially arranged (with the metal compound coating layer of each electrode sheet facing the separator) and sealed in a CR2320 coin cell.

[0114] Fabrication of Li-Li symmetric cells in solid (hybrid) polymer electrolytes Weighed Evonik ball milled c-LLZO was crushed and ground with polyethylene oxide (PEO, purchased from Sigma-Aldrich) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, purchased from Kishida Chemical Co., Ltd.). The LLZO was weighed to obtain a paste-like material, which was then annealed at 100 °C overnight and subsequently hot-pressed between Teflon substrates at 100 °C to achieve the desired thickness. The molar ratio of [O]:[Li] was set at 15:1. This hybrid electrolyte (HSE) was used as both a separator and a solid electrolyte. The first coated electrode sheet, the HSE with a thickness of approximately 110 μm, and a second (identical to the first) electrode sheet were arranged in sequence (with the metal compound coating layer of each electrode sheet facing the separator) and sealed in a CR2320 coin cell.

[0115] Electrochemical test (cell cycling test) Electrochemical cycling tests were performed at room temperature in an Arbin BT2000 battery tester using CR2032 type coin cells. The voltage versus time (cycle number) profile during galvanostatic cycling of Li-Li cells is related to electrode stability and failure. The voltage profiles of Li stripping and plating in Li-Li symmetric cells were measured at a current density of 0.1 mAh / cm. 2 and 0.5mAh / cm 2 was measured.

[0116] The procedure for Li-Li symmetric cell testing conducted at room temperature was as follows: Leave for 10 seconds a. 0.1mA / cm 2 Charge for 5 hours, record every 5 minutes, then leave for 10 minutes, b. 0.1mA / cm 2 Discharge for 5 hours, record every 5 minutes, then leave for 10 minutes. Repeat a and b for 5 cycles. c. 0.5mA / cm 2 Charge for 1 hour, record every 30 seconds, then leave for 10 minutes, d. 0.5mA / cm 2 Discharge for 1 hour, record every 30 seconds, then leave for 10 minutes. c and d are repeated for 5 cycles. e. 1mA / cm 2 Charge for 0.5 hours, record every 15 seconds, then leave for 10 minutes. f. 1mA / cm 2 Discharge for 0.5 hours, record every 15 seconds, then leave for 10 minutes. Repeat a and b for 5 cycles.

[0117] The voltage profile determination for various alumina particles was performed at a current density of 0.1 mA / cm as shown in Fig. 1a and Fig. 1a. 2 and 0.5mA / cm 2 showed the lowest polarization voltage for the system containing AEROXIDE® Alu130 alumina particles (Table 3: Example 1a vs. Examples 2a and 3a; Example 4a vs. Examples 5a and 6a).

[0118] With respect to the alumina particle:polymer ratio, the voltage profile at a blend ratio of AEROXIDE® Alu130 alumina particles to PVDF-HFP of 4:1 (FIG. 1, Table 3, Example 4a) showed the lowest polarization voltage and flattest profile of all the alumina samples and alumina particle:polymer ratios tested.

[0119] [Table 3-1]

[0120] The coated electrode sheets of Examples 4a, 5a and 6a, in which the blending ratio of alumina particles to PVDF-HFP was 4:1, were subjected to a current density of 1 mA / cm 2 , and plating and stripping capacity 0.5mAh / cm 2 The cycling performance of the Li-Li symmetric cell examples was compared by further cycling at 1000 s.p.m. (Example 4a: FIG. 2(C); Example 5a: FIG. 2(B); Example 6a: FIG. 2(A)). The electrodes of Examples 5a and 6a containing alumina particles TM-DAR and USR were unable to continue cycling, indicating that lithium dendrite formation was not prevented. On the other hand, Sample 4a was able to continue cycling for more than 200 cycles and also showed a stable polarization voltage profile, indicating that lithium dendrite formation was mitigated.

[0121] [Table 3-2]

[0122] Fabrication of Li-Cu asymmetric cells To further analyze the coulombic efficiency with the protective layer, Li-Cu asymmetric cells were fabricated.

[0123] The electrolyte composition was a 1 M solution of lithium bis(trifluoromethanesulfonyl)imide (Kishida, >99.9%) in a 1:1 (vol / vol) 1,3-dioxolane (supplier: Sigma-Aldrich, 99.8%):1,2-dimethoxyethane (supplier: Kishida, 99.9%) mixture containing 1% by weight lithium nitrate (supplier: Sigma-Aldrich, stored in a glove box for 1 week). The first coated electrode sheet, a polypropylene-polyethylene-polypropylene (PP / PE / PP) separator (Celgard® 2320, supplier: Celgard) with a thickness of approximately 10–20 μm, and a second (identical) electrode sheet were sequentially arranged (with the metal compound coating layer of each electrode sheet facing the separator) and sealed in a CR2320 coin cell.

[0124] Cycling Test Cycling tests using Li-Cu asymmetric cells were carried out for Examples 1b, 2b, 3b, 4b, 7b, 8b, 10b and 11b. The coulombic efficiency was measured.

[0125] CE of Li-Cu asymmetric cell avg The procedure for the test was as follows: a. 0.5mA / cm 2 Discharge for 10 hours, recording every 3 minutes, b. 0.5mA / cm 2 10 hours charging, recording every 3 minutes, Repeat a and b for two cycles. 0.5mA / cm 2 Discharge for 10 hours, recording every 3 minutes, 0.5mA / cm 2 Charge for 2 hours, record every 3 minutes, a. 0.5mA / cm 2 Discharge for 2 hours, recording every 3 minutes, b. 0.5mA / cm 2 Charge for 2 hours, record every 3 minutes, a and b are repeated for 11 cycles. 0.5mA / cm 2 Discharge for 2 hours, recording every 3 minutes, >0.5mA / cm up to 1V 2 Charges with, records every 3 minutes.

[0126] The procedure for CE cycling testing of the Li-Cu asymmetric cell was as follows: a. 0.5mA / cm 2 Discharge for 2 hours, recording every 3 minutes, b. 0.5mA / cm up to >1V 2 Charge with, record every 3 minutes, Repeat a and b.

[0127] In all cases, the use of alumina-polymer coatings resulted in improved electrode coulombic efficiency compared to uncoated electrode materials (reference). Increasing the alumina particle to polymer mass ratio, as well as using smaller alumina particle sizes, particularly with fumed alumina in Example 4b, significantly improved the coulombic efficiency of Li-Cu asymmetric cells (Figure 3, Table 4).

[0128] [Table 4]

[0129] The volume expansion rate was measured by SEM analysis. Current density: 0.5 mA / cm 2 and capacity 2mAh / cm 2 The thickness change before (10 μm) and after 10 cycles was measured and analyzed in SEM images of the cells relative to a reference without an alumina-polymer coating (reference value 100%). The volume expansion coefficients of the electrodes from Examples 8b, 7b, and 4b are shown in Figures 4(A), 4(B), and 4(C), respectively.

[0130] The procedure for the Li expansion test on Cu foil was as follows: a. 0.5mA / cm 2 Discharge for 4 hours, recording every minute, b. 0.5mA / cm up to >1V 2 Charge, record every minute, c. 0.5mA / cm 2 Discharge for 4 hours, recording every minute.

[0131] For the electrode of Example 4b, this value was minimized to 10%, while electrodes from Examples 7b and 8b, which have a higher alumina:polymer mass ratio but alumina types other than that of Example 4b, resulted in volume expansion rates of 30% and 50%, respectively (Table 4).

Claims

1. 1. An electrode for a lithium battery, comprising an organic binder and aluminum oxide, a material of the general formula Li a Zr b M c O 0.5a+2b+d (I) [In the formula, 1.5≦a≦15, 0.5≦b≦3.0, 0≦c≦5, M=Al, La and d=1.5c] and a fumed metal compound selected from the group consisting of a zirconium-containing mixed oxide of 1000 to 15000 kJ / cm2, and a mixture thereof, wherein the metal compound has a number average primary particle size d 50 The electrode is composed of a strong agglomerate of primary particles having a size of 5 nm to 100 nm, and the mass ratio of the metal compound to the organic binder in the coating layer is 0.1 to 10.

2. Lithium hexafluorophosphate (LiPF 6 ), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO 4 ), lithium tetrafluoroborate (LiBF 4 ), Li 2 SiF 6 , lithium triflate, lithium bis(perfluoroethylsulfonyl)imide (LiN(SO 2 CF 2 CF 3 ) 2 10. The electrode of claim 1, further comprising a lithium salt selected from the group consisting of lithium nitrate, lithium bis(oxalato)borate, lithium-cyclo-difluoromethane-1,1-bis(sulfonyl)imide, lithium-cyclo-hexafluoropropane-1,1-bis(sulfonyl)imide, and mixtures thereof.

3. 3. The electrode of claim 1, wherein the metal compound is surface-treated with a surface treatment agent selected from the group consisting of organosilanes, silazanes, acyclic polysiloxanes, cyclic polysiloxanes, and mixtures thereof.

4. The metal compound has a number average strongly agglomerated particle size d 50 4. The electrode according to claim 1, having a thickness of 20 nm to 1 μm.

5. 5. The electrode according to claim 1, wherein the weight ratio of the metal compound to the organic binder in the coating layer is 1 to 6.

6. 6. The electrode of claim 1, wherein the organic binder is selected from the group consisting of poly(vinylidene fluoride), copolymers of vinylidene fluoride and hexafluoropropylene, poly(vinyl acetate), poly(ethylene oxide), poly(methyl methacrylate), poly(ethyl acrylate), poly(vinyl chloride), poly(urethane), poly(acrylonitrile), copolymers of ethylene and vinyl acetate, carboxymethyl cellulose, poly(imide), poly(dimethylsiloxane), poly(ethylene oxide), and mixtures thereof.

7. 6. The electrode of claim 1, wherein the metal layer is selected from the group consisting of lithium, aluminum, copper, silver, gold, nickel, iron, steel, stainless steel, titanium, or alloys thereof.

8. 8. The electrode of claim 1, comprising a metal layer having a thickness of 0.5 μm to 500 μm.

9. 9. The electrode according to claim 1, wherein the coating layer has a thickness of 0.5 μm to 100 μm.

10. 10. A method for manufacturing an electrode as defined in any one of claims 1 to 9, comprising the following steps: (1) An organic binder and aluminum oxide, a compound of the general formula Li a Zr b M c O 0.5a+2b+d (I) [In the formula, 1.5≦a≦15, 0.5≦b≦3.0, 0≦c≦5, M=Al, La and d=1.5c] and mixtures thereof, and optionally a solvent, wherein the metal compound has a number average primary particle size d 50 the step of: consisting of a strong agglomerate of primary particles having a size of 5 nm to 100 nm and obtained by a pyrolysis method, wherein the mass ratio of the metal compound to the organic binder is 0.1 to 10; (2) coating the mixture prepared in step (1) onto the surface of the metal layer; (3) optionally drying and / or curing the coating layer produced in step (2); The method comprising:

11. 11. The process of claim 10, wherein the solvent used in step (1) is selected from the group consisting of 1,2-dimethoxyethane, diethyl ether, tetrahydrofuran, dioxane, bis(2-methoxyethyl)ether, pentane, hexane, heptane, octane, decane, toluene, ethanol, isopropanol, N-methyl-2-pyrrolidone, triethyl phosphate, dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone, benzaldehyde, N,N-dimethylformamide, dimethylacetamide, acetonitrile, cyclohexanone, ethyl acetate, propylene carbonate, ethylene carbonate, diethylene glycol monomethyl ether, triethylene glycol methyl ether, acetylacetone, acetone, and mixtures thereof.

12. 10. Use of an electrode according to any one of claims 1 to 9 as a component of a lithium metal or lithium ion battery.

13. A battery comprising an electrode according to any one of claims 1 to 9.

Images