Positive electrode for all-solid-state battery, positive electrode composition, and all-solid-state battery

Abstract

The present invention relates to a positive electrode for an all-solid-state battery, a positive electrode composition, and an all-solid-state battery comprising the positive electrode. The positive electrode for an all-solid-state battery comprises a current collector and a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer comprises a positive electrode active material, a sulfide-based solid electrolyte, a dispersion medium comprising a compound of chemical formula 1, a binder, an electrolyte salt, a crosslinked product of: a bifunctional or higher glycidyl ether-based compound having an alkylene glycol group; or a mixture comprising same, and a conductive material.

Description

Cathode for all-solid-state battery, cathode composition, and all-solid-state battery

[0001] It relates to a cathode for an all-solid-state battery, a cathode composition, and an all-solid-state battery.

[0002]

[0003] Lithium secondary batteries, which offer high energy density and portability, are primarily used as power sources for mobile information terminals such as mobile phones, laptops, and smartphones. However, because lithium secondary batteries use electrolytes, they pose safety concerns, such as explosion or fire in the event of collisions or penetrations. All-solid-state batteries, which utilize solid electrolytes instead of electrolytes, are being proposed. All-solid-state batteries are safe because they eliminate the risk of electrolyte leakage and explosion, and they also offer the advantage of being easy to manufacture in thinner forms.

[0004] The background technology is described in Korean Patent No. 10-2350047, etc.

[0005]

[0006] Provided are a cathode for an all-solid-state battery, a cathode composition, and an all-solid-state battery that suppress deterioration of a sulfide-based solid electrolyte, have high adhesion between a current collector or a plate and a cathode active material layer, have high strength of the cathode active material layer, improve ionic conductivity and electronic conductivity, enable stable cycling, and realize high capacity, high efficiency, and long lifespan.

[0007]

[0008] In one embodiment, a positive electrode for an all-solid-state battery comprising a current collector and a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer comprises: a positive electrode active material; a sulfide-based solid electrolyte; a dispersion medium comprising a compound of formula 1; a binder; an electrolyte salt; a crosslinked product of a difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture thereof; and a conductive material:

[0009] [Chemical Formula 1]

[0010] CH3C(=O)OR 1

[0011] R 1 is an alkyl group of C7 to C9.

[0012] In another embodiment, a method for producing a positive electrode composition for an all-solid-state battery is provided, comprising the steps of producing a preliminary composition including a positive electrode active material; a sulfide-based solid electrolyte; a dispersion medium including a compound of formula 1; a binder; a difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture including the same; and a conductive agent, and adding an electrolyte salt to the preliminary composition.

[0013] In another embodiment, an all-solid-state battery is provided comprising the aforementioned positive electrode, negative electrode, and a solid electrolyte layer positioned between the positive electrode and negative electrode.

[0014]

[0015] According to an embodiment, a positive electrode for an all-solid-state battery can suppress deterioration of a sulfide-based solid electrolyte, have high adhesion between a current collector or a plate and a positive electrode active material layer, have high strength of the positive electrode active material layer, improve ionic conductivity and electronic conductivity, enable stable cycling, and realize high capacity, high efficiency, and long lifespan.

[0016]

[0017] Figures 1 and 2 are cross-sectional views schematically illustrating an all-solid-state battery according to one embodiment.

[0018] Figure 3 is a voltage graph according to the specific capacity of the battery, showing the results of evaluating the life characteristics of the batteries of Example 1 (solid line), Comparative Example 1 (dotted line), and Comparative Example 2 (double-dashed line).

[0019]

[0020] Below, specific implementation examples are described in detail to facilitate their implementation by those skilled in the art. However, the present invention may be implemented in various different forms and is not limited to the implementation examples described herein.

[0021] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0022] Here, “combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0023] It should be understood that the terms "include," "comprising," or "having" herein are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0024] To clearly illustrate various layers and regions in the drawings, their thicknesses are enlarged, and similar parts are designated by the same drawing reference numerals throughout the specification. When an element such as a layer, film, region, or plate is said to be "over" or "on" another element, this includes not only the case where it is "directly over" the other element, but also the case where there is another element in between. Conversely, when an element is said to be "directly over" another element, it means that there is no other element in between.

[0025] Also, the term "layer" here includes not only a shape formed on the entire surface when observed in a plan view, but also a shape formed on a portion of the surface.

[0026] In addition, the average particle diameter and average size, etc. can be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope photograph or a scanning electron microscope photograph. Alternatively, the size, etc. can be measured using a dynamic light scattering method, data analysis can be performed, the number of particles for each particle size range can be counted, and then the average particle diameter can be calculated from this. Unless otherwise defined, the average particle diameter is measured with a particle size analyzer and means the diameter of particles (D50) in the particle size distribution that have a cumulative volume of 50% by volume. The average particle diameter and average size can be obtained from the diameter of the cross-section if the material is spherical, or from the longest length of the cross-section if the material is not spherical.

[0027] “Or” is not interpreted as exclusive, for example, “A or B” is interpreted as including A, B, A+B, etc.

[0028] Here, “electrode plate” may have the same meaning as “positive electrode active material layer.”

[0029] anode

[0030] In one embodiment, there is provided a positive electrode for an all-solid-state battery, comprising a current collector and a positive electrode active material layer positioned on the current collector. The positive electrode active material layer comprises: a positive electrode active material; a sulfide-based solid electrolyte; a dispersion medium comprising a compound of formula 1; a binder; an electrolyte salt; a crosslinked product of a difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture thereof; and a conductive material.

[0031] Here, the entire body may be, but is not limited to, aluminum foil, for example:

[0032] [Chemical Formula 1]

[0033] CH3C(=O)OR 1

[0034] R1 is an alkyl group of C7 to C9.

[0035] The above C7 and C9 represent the number of carbon atoms. That is, R 1 is an alkyl group having 7 to 9 carbon atoms. R 1 The alkyl group may be a chain-like alkyl group or a cyclic alkyl group, and may be a straight-chain or branched alkyl group.

[0036] R in chemical formula 1 1 For example, it can be a C7 to C8 alkyl group, or a C8 to C9 alkyl group. The compound represented by the chemical formula 1 can be expressed as a C7 to C9 alkyl acetate, and can be, for example, octyl acetate including heptyl acetate, n-octyl acetate, or nonyl acetate. For example, the compound represented by the chemical formula 1 can be octyl acetate including n-octyl acetate, etc.

[0037] For all-solid-state batteries to become commercially viable, applying a wet coating process to the positive electrode active material layer is advantageous. However, using conventional polar solvents during wet coating of the positive electrode active material layer composition poses the problem of the sulfide-based solid electrolyte dissolving in or being degraded by the polar solvent. However, using nonpolar solvents such as heptane can lead to binder insolubility, preventing plate formation.

[0038] The compound of chemical formula 1 is a nonpolar solvent and has very low reactivity with a sulfide-based solid electrolyte, so it does not deteriorate the sulfide-based solid electrolyte, does not increase cell resistance, dissolves binders well, and has an appropriate viscosity, enabling uniform coating on the electrode plate. Furthermore, the compound does not require harsh conditions during the electrode plate drying process, and can be effectively dried at room temperature or relatively low temperature conditions or at normal pressure conditions, thereby preventing the problem of additional deterioration of the sulfide-based solid electrolyte during the drying process.

[0039] Meanwhile, all-solid-state batteries face the problem of increased resistance between solid interfaces within the positive electrode plates. To address this issue, a method of incorporating an electrolyte salt containing an ionic substance into the positive electrode active material layer may be considered. For the electrolyte salt to be incorporated into the positive electrode active material layer without phase separation from non-solid materials, such as a binder, the electrolyte salt must be highly soluble in the dispersion medium.

[0040] A crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same can form a semi-IPN structure together with a binder described below.

[0041] In one specific example, the semi-IPN structure may have a form in which the binder is entangled in a network shape in a cross-linked product of the bifunctional or higher glycidyl ether compound having the alkylene glycol group or a mixture containing the same. However, the semi-IPN structure is different from an IPN structure in which the cross-linked product and the binder undergo a cross-linking reaction with each other. The semi-IPN structure can increase the strength of the positive electrode active material layer and increase the adhesion of the positive electrode active material layer to the current collector compared to the binder alone or the cross-linked product alone.

[0042] In one specific example, the crosslinker can be formed by an initiation reaction of a bifunctional or more functional glycidyl ether compound having an alkylene glycol group or an electrolyte salt of the mixture described below.

[0043] In one specific example, the semi-IPN structure may be formed by adding the binder to the crosslinker.

[0044] In another specific example, the semi-IPN structure can be prepared by preparing a mixture of the difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same and the binder, and adding the electrolyte salt and performing a crosslinking reaction immediately before performing the crosslinking reaction. In the case where the electrolyte salt is added in advance before performing the crosslinking reaction after preparing a mixture of the difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same and the binder, the crosslinking reaction occurs only with the difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture thereof, resulting in phase separation between the crosslinked product and the binder, and thus the semi-IPN structure cannot be formed.

[0045] In addition, the crosslinker can dissolve the electrolyte salt with high solubility in a dispersion medium containing the compound represented by Chemical Formula 1 in the positive electrode composition without precipitation of the electrolyte salt. This increases the concentration of salts or ions dissociated from the electrolyte salt in the binder in the positive electrode active material layer, thereby increasing the ionic conductivity of the binder and the positive electrode active material layer. For example, the electrolyte salt may be a fluorine-containing lithium salt.

[0046] A crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture thereof has low adhesion to a plate or a current collector even when networked. However, the crosslinked product can increase adhesion between the plate and the positive electrode active material layer or solid materials within the positive electrode active material layer by forming a network through an ionic crosslinking phenomenon with an electrolyte salt. The high adhesion between the plate and the positive electrode active material layer can increase the electronic conductivity of the entire positive electrode, thereby improving the physical properties of the entire positive electrode. For example, the electrolyte salt may be a fluorine-containing lithium salt.

[0047] Meanwhile, sulfide-based solid electrolytes are highly reactive, as is known to those skilled in the art. This high reactivity can cause a decline in the performance of all-solid-state batteries. The above-mentioned difunctional or higher glycidyl ether compound having an alkylene glycol group, the mixture thereof, or the crosslinked product has low reactivity toward the sulfide-based solid electrolyte. Therefore, a positive electrode further comprising the above-mentioned difunctional or higher glycidyl ether compound having an alkylene glycol group, the mixture thereof, or the crosslinked product in combination with the sulfide-based solid electrolyte, the dispersion medium comprising the chemical formula 1, and the electrolyte salt can realize high capacity, high efficiency, and long life characteristics in an all-solid-state battery. Preferably, the sulfide-based solid electrolyte may be a compound described below.

[0048] A crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same can be added to a combination or assembly of a binder and an electrolyte salt, i.e., a lithium conductive binder, to improve the ionic conductivity and adhesiveness of the binder.

[0049] In one embodiment, the binder, the electrolyte salt, and the entire cross-linking agent may be included in the positive electrode active material layer in the form of an adhesive elastomer. Here, the term "adhesive elastomer" refers to a form in which the binder and the electrolyte salt are dispersed in the cross-linking agent.

[0050] The adhesive elastomer has flexibility and elasticity as well as adhesiveness, and thus can easily enhance the adhesion between the electrode plate or current collector and the positive electrode active material layer. On the other hand, conventional elastomers have flexibility and elasticity but lack adhesiveness, and thus may be insufficient in enhancing the adhesion between the electrode plate or current collector and the positive electrode active material layer. Adhesive gums have adhesiveness but lack elasticity and / or flexibility, and thus may be difficult to incorporate with solid materials in the positive electrode active material layer. The adhesive elastomer enhances the adhesion between the electrode plate or current collector and the positive electrode active material layer, and the enhanced adhesion can stabilize the interface between the solid materials in the positive electrode plate.

[0051] According to one embodiment, as the content of a crosslinked product of a bifunctional or more functional glycidyl ether compound having an alkylene glycol group or a mixture containing the same in the positive electrode active material layer increases, the form may change in the order of a non-adhesive conventional elastomer, an adhesive elastomer, and an adhesive gum.

[0052] According to one embodiment, the crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same may be contained in an amount of 1 to 30 wt%, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 wt%, 1 to 25 wt%, 5 to 20 wt%, of the remaining portion excluding the positive electrode active material, the sulfide-based solid electrolyte, and the conductive material in the positive electrode active material layer. In the above range, implementation of the adhesive elastomer may be easy.

[0053] According to one embodiment, the crosslinked product of a bifunctional or more functional glycidyl ether compound having an alkylene glycol group or a mixture containing the same may be contained in an amount of 1 to 30 wt% of the total of the binder; the electrolyte salt; and the crosslinked product, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 wt%, 1 to 25 wt%, 5 to 20 wt%. In the above range, the implementation of the adhesive elastomer may be easy.

[0054] According to one embodiment, at least a portion of a crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same may be dispersed within a positive electrode active material layer by being combined with at least one of a binder and an electrolyte salt. This may be advantageous in increasing the ionic conductivity of the positive electrode active material layer.

[0055] According to one embodiment, the crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same may be contained in an amount of 99 wt% or more, for example, 99 to 100 wt%, of the total glycidyl ether compound contained in the positive electrode active material layer.

[0056] Dispersant

[0057] The dispersion medium contains the compound of the above chemical formula 1.

[0058] Meanwhile, an all-solid-state battery positive electrode can be manufactured through the steps of preparing a positive electrode composition as described below; and coating and drying the positive electrode composition on a current collector. In this positive electrode manufacturing method, the coating is a wet coating, which is advantageous for application to existing processes, and uniform coating is possible by applying the positive electrode composition. Furthermore, the drying can be performed at a relatively low temperature and atmospheric pressure, making it economical and efficient. The drying can be performed at, for example, 20°C to 100°C, 30°C to 90°C, or 50°C to 85°C, and can be performed at atmospheric pressure.

[0059] During the above drying process, it was confirmed that most of the compound represented by Chemical Formula 1 was vaporized and a small amount remained. Accordingly, the positive electrode for the all-solid-state battery can be explained as also including the compound represented by Chemical Formula 1. Such a positive electrode can realize high capacity, high efficiency, and long life without deterioration of each component, particularly the sulfide-based solid electrolyte.

[0060] With respect to the total weight of the positive electrode active material layer, the compound represented by Chemical Formula 1 may be included in an amount of 0.1 wt% or less, for example, 0.0001 wt% to 0.1 wt%, 0.0001 wt% to 0.05 wt%, 0.0001 wt% to 0.04 wt%, 0.0001 wt% to 0.03 wt%, 0.0001 wt% to 0.02 wt%, 0.0001 wt% to 0.01 wt%, 0.001 wt% to 0.01 wt%, 0.001 wt% to 0.005 wt%, or 0.005 wt% to 0.01 wt%. It can be said that the compound represented by Chemical Formula 1 used as a kind of dispersion medium in the positive electrode composition during the manufacture of the positive electrode remains in the final positive electrode active material layer in such a small amount.

[0061] The dispersion medium may additionally include a compound of the following chemical formula 2:

[0062] [Chemical Formula 2]

[0063] CH3CH2C(=O)OR 2

[0064] R 2 is an alkyl group of C5 to C9.

[0065] The above C5 and C9 represent the number of carbon atoms. That is, R 2 is an alkyl group having 5 to 9 carbon atoms. R 2 may be a chain-shaped alkyl group or a cyclic alkyl group, and may be a straight-chain or branched alkyl group. In the above chemical formula 2, R 2 For example, it can be a C5 to C8 alkyl group, a C5 to C7 alkyl group, a C5 to C6 alkyl group, a C6 to C9 alkyl group, a C7 to C9 alkyl group, or a C8 to C9 alkyl group. The compound represented by the above chemical formula 2 can be expressed as a C5 to C9 alkyl propionate, and can be, for example, pentyl propionate, hexyl propionate, heptyl propionate, octyl propionate, or nonyl propionate.

[0066] Since the dispersion medium includes both the compound represented by chemical formula 1 and the compound represented by chemical formula 2, uniform coating is possible and drying under normal conditions is possible, which can help effectively suppress deterioration of the sulfide-based solid electrolyte and the electrode plate.

[0067] With respect to the total weight of the positive electrode active material layer, the compound represented by Chemical Formula 2 may be included in an amount of 0.1 wt% or less, for example, 0 wt% to 0.1 wt%, 0.0001 wt% to 0.1 wt%, 0.0001 wt% to 0.05 wt%, 0.0001 wt% to 0.04 wt%, 0.0001 wt% to 0.03 wt%, 0.0001 wt% to 0.02 wt%, 0.0001 wt% to 0.01 wt%, 0.001 wt% to 0.01 wt%, 0.001 wt% to 0.005 wt%, or 0.005 wt% to 0.01 wt%.

[0068] The compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 2 may react with each other or cause a chemical reaction with other components in the battery during the battery manufacturing process or during battery operation, and accordingly, a derivative (or modified substance) of the compound represented by Chemical Formula 1 and / or a derivative (or modified substance) of the compound represented by Chemical Formula 2 may be present in the final positive electrode active material layer.

[0069] For example, when octyl acetate and pentyl propionate are used as dispersants in a cathode composition during battery manufacturing, octyl propionate may be detected in the final cathode active material layer through a mutual reaction or other reaction. In this case, not only the dispersant pentyl propionate but also its derivative octyl propionate both correspond to the compound represented by the above chemical formula 2.

[0070] Additionally, the compounds represented by Chemical Formula 1 and Chemical Formula 2 may be decomposed into alcohols through a chemical reaction during the battery manufacturing process or battery operation. That is, an alcohol-type derivative may be detected within the positive electrode active material layer. For example, the positive electrode active material layer may further include a compound represented by Chemical Formula 3 below.

[0071] [Chemical Formula 3]

[0072] R 3 -OH

[0073] (In the above chemical formula 3,

[0074] R 3 is an alkyl group of C5 to C9.)

[0075] In the above chemical formula 3, R 3 is an alkyl group having 5 to 9 carbon atoms, and may be a chain alkyl group or a cyclic alkyl group, and may be a straight-chain or branched alkyl group. R 3 For example, it can be a C5 to C7 alkyl group, or a C7 to C9 alkyl group. The compound represented by the above chemical formula 3 can be expressed as a C5 to C9 alcohol, and can be, for example, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, or nonyl alcohol.

[0076] The compound represented by chemical formula 3 is not a component used as a dispersion medium in the manufacture of the anode, but can be said to be a derivative of the compound represented by chemical formula 1 and / or a derivative of the compound represented by chemical formula 2.

[0077] The compound represented by Chemical Formula 3 may likewise be included in an amount of 0.1 wt% or less based on the total weight of the positive electrode active material layer, for example, 0.0001 wt% to 0.1 wt%, 0.0001 wt% to 0.05 wt%, 0.0001 wt% to 0.04 wt%, 0.0001 wt% to 0.03 wt%, 0.0001 wt% to 0.02 wt%, 0.0001 wt% to 0.01 wt%, 0.001 wt% to 0.01 wt%, 0.001 wt% to 0.005 wt%, or 0.005 wt% to 0.01 wt%.

[0078] The method for analyzing the compound represented by chemical formula 1, the compound represented by chemical formula 2, and / or the compound represented by chemical formula 3 within the positive electrode active material layer is as follows:

[0079] After scraping 0.5 g of the positive electrode plate from the all-solid-state battery, it is immersed in a 2 mL diethyl carbonate (DEC) solution. After ultrasonic dispersion for 30 minutes, the solution is filtered using a 0.25 μm polytetrafluoroethylene (PTFE) filter. The obtained material is analyzed for components using GC / FID (Gas Chromatography-Flame Ionization Detector). The gas chromatography conditions are as follows.

[0080] (1) Column: RTX-200 (30m x 320um, 1 um)

[0081] (2) Flow: 4mL / min

[0082] (3) Inlet: 210℃

[0083] (4) oven temp.: 50 / 0-10-250 / 0, 5:1

[0084] electrolyte salt

[0085] The electrolyte salt can form the semi-IPN structure by crosslinking a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same to form the crosslinked product.

[0086] The electrolyte salt can be ionized within the binder to reduce the resistance between the solid interfaces within the positive electrode plates. The electrolyte salt is a solid material and may include one or more of an inorganic lithium salt and an organic lithium salt. In one specific example, the electrolyte salt may include a combination of an inorganic lithium salt and an organic lithium salt.

[0087] Inorganic lithium salts can be inorganic fluoride salts such as LiPF6, LiBF4, LiAsF6, LiSbF6, etc.; perhalogen salts such as LiClO4, LiBrO4, LiIO4, etc.; and inorganic chloride salts such as LiAlCl4. For example, the inorganic lithium salt can be LiBF4.

[0088] The organic lithium salt may include at least one of a perfluoroalkane sulfonate such as LiCF3SO3, a perfluoroalkanesulfonylimide salt such as LiN(CF3SO2)2, LiN(CF3CF2SO2)2, LiN(FSO2)2, LiN(CF3SO2)(C4F9SO2), a perfluoroalkanesulfonyl methide salt such as LiC(CF3SO2)3, a fluoroalkylfluorophosphate such as Li[PF5(CF2CF2CF3)], Li[PF4(CF2CF2CF3)2], Li[PF3(CF2CF2CF3)3], Li[PF5(CF2CF2CF2CF3)], Li[PF4(CF2CF2CF2CF3)2], Li[PF3(CF2CF2CF2CF3)3]. For example, the organic lithium salt may be a perfluoroalkanesulfonylimide salt.

[0089] According to one embodiment, the electrolyte salt may be a combination of a fluorine-containing organic lithium salt and an inorganic fluoride salt. For example, the electrolyte salt may be a combination of a perfluoroalkanesulfonylimide salt and LiBF4. This combination may facilitate the implementation of the above-described effects.

[0090] In the positive electrode active material layer, the electrolyte salt may be included in an amount of 0.001 to 10 wt% based on the total weight of the positive electrode active material layer, for example, 0.001 to 5 wt%, 0.01 to 1 wt%, or 0.01 to 0.5 wt%. When the electrolyte salt is included in such an amount, the positive electrode active material layer may be easily capable of providing the above-described effects.

[0091] Crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same

[0092] The above bifunctional or higher glycidyl ether compound having an alkylene glycol group is *-[-OR 4 -]*(* is the connection part of the element, R 4It may be a compound having 2 moles or more of a straight-chain or branched-chain alkylene group unit having 1 to 5 carbon atoms per molecule.

[0093] In one specific embodiment, the compound may include one or more of the compounds represented by Chemical Formula 4:

[0094] [Chemical Formula 4]

[0095]

[0096] (In the above chemical formula 4,

[0097] R 4 is a straight or branched alkylene group having 1 to 5 carbon atoms.

[0098] R 5 and R 6 are each independently a single bond or an alkylene group having 1 to 5 carbon atoms,

[0099] n is an integer between 2 and 1000)

[0100] For example, the bifunctional or higher glycidyl ether compound having an alkylene glycol group may include at least one poly(ethylene glycol) diglycidyl ether (chemical formula 5 below).

[0101] [Chemical Formula 5]

[0102]

[0103] (n is an integer between 2 and 1000)

[0104] The bifunctional or higher glycidyl ether compound having an alkylene glycol group may have a number average molecular weight (Mn) of 300 to 2000, for example, 400 to 1500, 500 to 1000, or 500 to 800. Within this range, the formation of an adhesive elastomer may be facilitated. The number average molecular weight may be measured by a conventional method known to those skilled in the art and may be obtained, for example, through polystyrene conversion by gel permeation chromatography.

[0105] In one specific example, the positive electrode active material layer may include a crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group, for example, an oligomer thereof or a polymer thereof.

[0106] The above mixture may include a bifunctional or higher glycidyl ether compound having an alkylene glycol group and a bifunctional or higher amine compound having an alkylene glycol group.

[0107] The above-mentioned bifunctional or higher amine compound having an alkylene glycol group has an amine group at the terminal, and when used in combination with a bifunctional or higher glycidyl ether compound having an alkylene glycol group, a polymerization and / or crosslinking reaction between the amine group and the epoxy is induced, thereby facilitating the formation of the above-mentioned semi-IPN structure.

[0108] In one specific example, the bifunctional or more amine compound having the alkylene glycol group may include a compound of the following chemical formula 6:

[0109] [Chemical Formula 6]

[0110]

[0111] (In the above chemical formula 6,

[0112] R 7 A straight or branched alkylene group having 1 to 5 carbon atoms

[0113] R 8 is a single bond or an alkylene group having 1 to 5 carbon atoms,

[0114] n is an integer between 2 and 1000)

[0115] For example, the bifunctional or higher amine compound having an alkylene glycol group may include one or more poly(ethylene glycol) diamines (chemical formula 7 below).

[0116] [Chemical Formula 7]

[0117]

[0118] (n is an integer between 2 and 1000)

[0119] In one specific example, the positive electrode active material layer may include a crosslinked product of a mixture of a bifunctional or higher glycidyl ether compound having an alkylene glycol group and a bifunctional or higher diamine compound having an alkylene glycol group.

[0120] For example, the mixture may include a difunctional or higher glycidyl ether compound having an alkylene glycol group: a difunctional or higher diamine compound having an alkylene glycol group in a molar ratio of 1:0.01 to 1:1.

[0121] Among the positive electrode active material layers, a diglycidyl ether compound having two or more functional groups having an alkylene glycol group or a crosslinked product of a mixture containing the same may be included in an amount of 0.001 to 1 wt%, for example, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5 wt%, 0.005 to 0.5 wt%, 0.01 to 0.1 wt%, or 0.01 to 0.05 wt%. In the above range, the positive electrode active material layer can easily achieve the above-described effect.

[0122] bookbinder

[0123] The binder can play a role in attaching positive electrode active material particles well to each other and in attaching the positive electrode active material well to the current collector.

[0124] Examples of the above binder include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene, polypropylene, styrene butadiene rubber, acrylated styrene butadiene rubber, polyacrylonitrile, epoxy resin, nylon, poly(meth)acrylate, polymethyl(meth)acrylate, and the like.

[0125] Among them, the binder according to one embodiment may be at least one selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, styrene butadiene rubber, polyacrylonitrile, and polymethyl(meth)acrylate. These binders may be well dissolved in the compound represented by chemical formula 1, which is a dispersion medium in the positive electrode composition, and thus uniform coating may be possible and excellent electrode plate performance may be realized. For example, the binder may be polyvinylidene fluoride-hexafluoropropylene copolymer.

[0126] The binder may be included in an amount of 0.1 to 5 wt%, for example, 0.1 to 3 wt%, relative to the total weight of each component of the positive electrode or relative to the total weight of the positive electrode active material layer. When the binder is included in such an amount, the positive electrode active material layer can easily achieve the effects of the present invention.

[0127] positive electrode active material

[0128] As a positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used. Examples of the positive electrode active material include compounds represented by one of the following chemical formulas:

[0129] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0130] Li a A 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0131] Li a E 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0132] Li a E 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0133] Li a Ni 1-b-c Co b X c D α (0.90 ≤ a ≤1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 < α ≤ 2);

[0134] Li a Ni 1-b-c Co b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0135] Lia Nor 1-b-c Co b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0136] The a Nor 1-b-c Mn b X c D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2);

[0137] The a Nor 1-b-c Mn b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0138] The a Nor 1-b-c Mn b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0139] The a Nor b E c G d O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1);

[0140] The a Nor b Co c Mn d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

[0141] The a NiG bO2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0142] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0143] Li a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0144] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0145] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0146] QO2; QS2; LiQS2;

[0147] V2O5; LiV2O5;

[0148] LiZO2;

[0149] LiNiVO4;

[0150] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0151] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0152] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0153] In the above chemical formulas, A is selected from the group consisting of Ni, Co, Mn, and combinations thereof; X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof; D is selected from the group consisting of O, F, S, P, and combinations thereof; E is selected from the group consisting of Co, Mn, and combinations thereof; T is selected from the group consisting of F, S, P, and combinations thereof; G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof; Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof; J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0154] The above positive electrode active material may be a lithium-metal composite oxide, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide (LMO), or lithium iron phosphate (LFP).

[0155] A compound having a coating layer on the surface of the compound may be used, or a compound having the compound and a coating layer may be mixed and used. The coating layer may include at least one coating element compound selected from the group consisting of an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, and a hydroxycarbonate of the coating element. The compounds forming these coating layers may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a combination thereof. For example, the coating layer may include Li2O-ZrO2 (LZO). The coating layer forming process may use a method that does not adversely affect the properties of the positive electrode active material, such as spray coating or dipping.

[0156] The above positive electrode active material may include, for example, one or more types of lithium-metal composite oxides represented by the following chemical formula 8.

[0157] [Chemical Formula 8]

[0158] Li a M 11 1-y11-z11 M 12 y11 M 13 z11 O2

[0159] In the above chemical formula 8, 0.9≤a≤1.8, 0≤y11≤1, 0≤z11≤1, 0≤y11+z11<1, M 11 , M 12 and M 13 Each of which may be independently selected from elements such as Ni, Co, Mn, Al, Mg, Ti or Fe, and combinations thereof.

[0160] For example, the above M 11 can be Ni, and the above M 12 and M 13Each of which can independently be a metal such as Co, Mn, Al, Mg, Ti or Fe. In a specific embodiment, the M 11 can be Ni, and the above M 12 may be Co, and the above M 13 may be, but is not limited to, Mn or Al.

[0161] In one embodiment, the positive electrode active material may include a lithium nickel-based composite oxide represented by the following chemical formula 9.

[0162] [Chemical Formula 9]

[0163] Li a12 Ni x12 M 14 y12 M 15 1-x12-y12 O2

[0164] In the above chemical formula 9, 0.9≤a12≤1.8, 0.3≤x12≤1, 0≤y12≤0.7, and M 14 and M 15 is at least one element independently selected from Al, B, Ba, Ca, Ce, Co, Cr, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0165] The above positive electrode active material may include, for example, a lithium nickel cobalt oxide represented by the chemical formula 10 below.

[0166] [Chemical Formula 10]

[0167] Li a13 Ni x13 Co y13 M 16 1-x13-y13 O2

[0168] In the above chemical formula 10, 0.9≤a13≤1.8, 0.3≤x13<1, 0 <y13≤0.7이고 M 16is at least one element selected from Al, B, Ba, Ca, Ce, Cr, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0169] In the above chemical formula 10, 0.3≤x13≤0.99 and 0.01≤y13≤0.7 may be satisfied, 0.4≤x13≤0.99 and 0.01≤y13≤0.6 may be satisfied, 0.5≤x13≤0.99 and 0.01≤y13≤0.5 may be satisfied, 0.6≤x13≤0.99 and 0.01≤y13≤0.4 may be satisfied, 0.7≤x13≤0.99 and 0.01≤y13≤0.3 may be satisfied, 0.8≤x13≤0.99 and 0.01≤y13≤0.2 may be satisfied, or 0.9≤x13≤0.99 and 0.01≤y13≤0.1 may be satisfied.

[0170] The content of nickel in the lithium nickel-based composite oxide may be 30 mol% or more, for example, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more, and 99.9 mol% or less, or 99 mol% or less, based on the total amount of metals excluding lithium. For example, the content of nickel in the lithium nickel-based composite oxide may be higher than the content of each of the other metals, such as cobalt, manganese, and aluminum. When the content of nickel satisfies the above range, the positive electrode active material may exhibit excellent battery performance while implementing a high capacity.

[0171] The average particle size of the positive electrode active material may be from 1 μm to 25 μm, for example, from 4 μm to 25 μm, from 5 μm to 20 μm, from 8 μm to 20 μm, or from 10 μm to 18 μm. A positive electrode active material having such a particle size range can be harmoniously mixed with other components within the positive electrode active material layer and can realize high capacity and high energy density.

[0172] The positive electrode active material may be in the form of a secondary particle formed by agglomeration of multiple primary particles, or may be in the form of a single particle. In addition, the positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0173] With respect to the total weight of the positive electrode active material layer, the positive electrode active material may be included in an amount of 55 to 99 wt%, for example, 74 to 89.8 wt%. When included in the above range, the capacity of the all-solid-state battery can be maximized while improving the life characteristics.

[0174] solid electrolyte

[0175] The solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte or an oxide-based solid electrolyte, or a solid polymer electrolyte.

[0176] In one embodiment, the solid electrolyte may be a sulfide-based solid electrolyte having excellent ion conductivity. The sulfide-based solid electrolyte may be, for example, Li2S-P2S5, Li2S-P2S5--LiX (wherein X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga, or In).

[0177] The sulfide-based solid electrolyte can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be manufactured. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3. Mechanical milling or a solution method can be applied as a mixing method. Mechanical milling is a method in which starting materials are placed in a reactor and vigorously stirred with a ball mill, etc. to pulverize the starting materials and mix them. When a solution method is used, the starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. In addition, additional calcination can be performed after mixing. If additional calcination is performed, the crystals of the solid electrolyte can become more solid.

[0178] For example, the solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be, for example, Li a M b P c S d A e (a, b, c, d and e are all 0 or more and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I), and specifically Li3PS4, Li7P3S 11 , Li6PS5Cl, Li6PS5Br, Li6PS5I, etc. These sulfide-based solid electrolytes have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2Because it possesses a high ionic conductivity approaching the S / cm range, it can form a close bond between the positive electrode active material and the solid electrolyte without causing a decrease in ionic conductivity, and further, it can form a close interface between the electrode layer and the solid electrolyte layer. An all-solid-state battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0179] The sulfide-based solid electrolyte may be amorphous or crystalline, or may be a mixture of the two.

[0180] The solid electrolyte may be an oxide-based inorganic solid electrolyte other than a sulfide-based material. An example of an oxide-based inorganic solid electrolyte is Li. 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La yTiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0181] The solid electrolyte is in the form of particles and may have an average particle diameter (D50) of 5.0 μm or less, for example, 0.1 μm to 5.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 0.5 μm to 2.0 μm, or 0.5 μm to 1.0 μm. This solid electrolyte can effectively penetrate between positive electrode active materials and has excellent contact with the positive electrode active material and connectivity between solid electrolyte particles.

[0182] With respect to the total weight of the positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 to 35 wt%, for example, 1 to 35 wt%, 5 to 30 wt%, 8 to 25 wt%, or 10 to 20 wt%.

[0183] In addition, in the positive electrode active material layer, 65 wt% to 99 wt% of the positive electrode active material and 1 wt% to 35 wt% of the solid electrolyte may be included based on the total weight of the positive electrode active material and the solid electrolyte, for example, 80 wt% to 90 wt% of the positive electrode active material and 10 wt% to 20 wt% of the solid electrolyte may be included. When the solid electrolyte is included in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state battery can be improved without reducing the capacity.

[0184] Challenge

[0185] A conductive material is used to impart conductivity to the electrode, and any material that is electronically conductive and does not cause chemical changes can be used. The conductive material may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials containing copper, nickel, aluminum, silver, and the like in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0186] The conductive material may be included in an amount of 0.1 to 5 wt%, or 0.1 to 3 wt%, relative to the total weight of each component of the positive electrode for an all-solid-state battery, or relative to the total weight of the positive electrode active material layer. Within the above content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0187] The positive electrode active material layer may include, based on the total weight of the positive electrode active material, the solid electrolyte, the binder, and the conductive material, 55 wt% to 99 wt% of the positive electrode active material; 0.1 wt% to 35 wt% of the solid electrolyte; 0.1 wt% to 5 wt% of the binder; 0.001 wt% to 10 wt% of the electrolyte salt, 0.001 to 1 wt% of at least one of a bifunctional or higher glycidyl ether compound having an alkylene glycol group, an oligomer thereof, and a crosslinked product thereof, and 0.1 wt% to 5 wt% of the conductive material. As a specific example, the positive electrode active material layer may include 74 wt% to 89.8 wt% of the positive electrode active material; 10 wt% to 20 wt% of the solid electrolyte; 0.1 wt% to 3 wt% of the binder; The composition may include 0.001 to 5 wt% of an electrolyte salt, 0.005 to 0.5 wt% of a bifunctional or higher glycidyl ether compound having an alkylene glycol group, an oligomer thereof, or a crosslinked product thereof, and 0.1 to 3 wt% of a conductive material. When mixed in the above content range, the life characteristics of the battery can be improved while maximizing the capacity.

[0188] The positive electrode active material layer may further include a dispersant. The dispersant may facilitate the dispersion of each component in the positive electrode active material layer. The amount of the dispersant added may be appropriately adjusted.

[0189] Bipolar composition

[0190] According to one embodiment, a positive electrode composition includes a positive electrode active material, a sulfide-based solid electrolyte, a dispersion medium including a compound of formula 1, a binder, an electrolyte salt, a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture including the same; and a conductive material. Here, the positive electrode composition may also be expressed as a positive electrode active material layer composition, or a composition for forming a positive electrode active material layer.

[0191] The detailed description of the positive electrode active material, the sulfide-based solid electrolyte, the dispersion medium including the compound of formula 1, the binder, the electrolyte salt, the bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture including the same, and the conductive material is the same as described above.

[0192] Based on the solid content, the total 100 parts by weight may include 55 to 99 parts by weight of a positive electrode active material, 0.1 to 35 parts by weight of a sulfide-based solid electrolyte, 0.1 to 5 parts by weight of a binder, 0.001 to 10 parts by weight of an electrolyte salt, 0.001 to 1 part by weight of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same, and 0.1 to 5 parts by weight of a conductive agent, and 20 to 100 parts by weight, or 20 to 60 parts by weight, of a dispersion medium containing the chemical formula 1, based on the total 100 parts by weight. Within the above range, the effects of the present invention may be easily realized.

[0193] Method for producing anode composition

[0194] A method for manufacturing a positive electrode composition comprises the steps of manufacturing a preliminary composition including a positive electrode active material; a sulfide-based solid electrolyte; a dispersion medium including a compound of formula 1; a binder; a difunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture including the same; and a conductive agent, and adding an electrolyte salt to the preliminary composition.

[0195] The above electrolyte salt is added immediately before crosslinking the bifunctional or higher glycidyl ether compound having the alkylene glycol group or the mixture containing the same. This allows the semi-IPN structure to be formed well. The crosslinking is described in detail below.

[0196] Method for manufacturing anode

[0197] The above positive electrode can be manufactured by a method including the steps of coating a positive electrode composition on a current collector and crosslinking the positive electrode composition.

[0198] The above coating can be performed by a conventional method known to those skilled in the art.

[0199] The above crosslinking is thermal crosslinking and can be performed under conditions suitable for crosslinking the bifunctional or higher glycidyl ether compound having the alkylene glycol group or the mixture containing the same. For example, the crosslinking can include heat treatment at 50 to 100°C for 10 minutes to 6 hours. The heat treatment can be performed two or more times. For example, the crosslinking can include a first heat treatment at 50 to 100°C for 10 minutes to 1 hour and a second heat treatment at 50 to 100°C for 2 minutes to 5 hours. The second heat treatment can be performed under vacuum. According to one embodiment, the first heat treatment can be performed by drying the solvent, and the second heat treatment can be performed by crosslinking.

[0200] All-solid-state batteries

[0201] In one embodiment, an all-solid-state battery is provided, comprising the aforementioned positive electrode, negative electrode, and a solid electrolyte layer positioned between the positive electrode and negative electrode. The all-solid-state battery may also be referred to as an all-solid-state secondary battery, or an all-solid-state lithium secondary battery.

[0202] FIG. 1 is a cross-sectional view of an all-solid-state battery (100) according to one embodiment. Referring to FIG. 1, the all-solid-state battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative electrode collector (401) and a negative electrode active material layer (403), a solid electrolyte layer (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode collector (201) are laminated is housed in a case such as a pouch. The all-solid-state battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 1 illustrates one electrode assembly including a negative electrode (400), a solid electrolyte layer (300), and a positive electrode (200), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0203] cathode

[0204] An anode for an all-solid-state battery may include, for example, a current collector and a layer of anode active material positioned on the current collector. The layer of anode active material includes a cathode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0205] The above negative active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0206] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0207] As the above lithium metal alloy, an alloy of lithium and one or more metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0208] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and the Si-based negative electrode active material may be silicon, a silicon-carbon composite, or SiO. x(0<x<2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(상기 R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Q 및 R로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택되는 것을 사용할 수 있다.

[0209] The silicon-carbon composite may be, for example, a silicon-carbon composite including a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof. As the amorphous carbon precursor, coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin such as a phenol resin, a furan resin, or a polyimide resin may be used. At this time, the content of silicon may be 10 wt% to 50 wt% with respect to the total weight of the silicon-carbon composite. In addition, the content of the crystalline carbon may be 10 wt% to 70 wt% with respect to the total weight of the silicon-carbon composite, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to the total weight of the silicon-carbon composite. In addition, the thickness of the amorphous carbon coating layer may be 5 nm to 100 nm.

[0210] The average particle diameter (D50) of the above silicon particles may be 10 nm to 20 μm, for example, 10 nm to 200 nm. The silicon particles may exist in an oxidized form, and at this time, the atomic content ratio of Si:O in the silicon particles, which indicates the degree of oxidation, may be 99:1 to 33:67. The silicon particles may be SiO x It can be a particle, in which case SiO x The range of x in can be greater than 0 and less than 2.

[0211] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. The mixing ratio of the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material can be 1:99 to 90:10 by weight.

[0212] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0213] In one embodiment, the negative electrode active material layer further includes a binder and may optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0214] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may be an insoluble binder, a water-soluble binder, or a combination thereof.

[0215] The above-mentioned non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer containing ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.

[0216] The water-soluble binder may be a rubber-based binder or a polymer resin binder. The rubber-based binder may be selected from styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof. The polymer resin binder may be selected from polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0217] When a water-soluble binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li. The amount of such thickener may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0218] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and has electronic conductivity can be used. The conductive material may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials including copper, nickel, aluminum, and silver in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0219] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0220] Meanwhile, as an example, the above-mentioned all-solid-state battery negative electrode may be a precipitation-type negative electrode. The precipitation-type negative electrode refers to a negative electrode that does not have a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated when the battery is charged, and this acts as a negative electrode active material.

[0221] Fig. 2 is a schematic cross-sectional view of an all-solid-state battery (110) including a precipitated negative electrode. Referring to Fig. 2, the precipitated negative electrode (400') may include a current collector (401) and a negative electrode coating layer (405) positioned on the current collector. An all-solid-state battery including such a precipitated negative electrode (400') starts initial charging in a state in which no negative electrode active material is present, and upon charging, a high-density lithium metal or the like is precipitated between the current collector (401) and the negative electrode coating layer (405) to form a lithium metal layer (404), which may function as a negative electrode active material. Accordingly, in an all-solid-state battery that has been charged at least once, the precipitated negative electrode (400') may include a current collector (401), a lithium metal layer (404) positioned on the current collector, and a negative electrode coating layer (405) positioned on the metal layer. The above lithium metal layer (404) refers to a layer in which lithium metal, etc. is precipitated during the charging process of the battery, and may be referred to as a metal layer or a negative electrode active material layer.

[0222] The above cathode coating layer (405) may include a metal and / or carbon material that acts as a catalyst.

[0223] The metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one kind of these or may be composed of several kinds of alloys. The average particle diameter (D50) of the metal may be about 4 μm or less, and may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 1 μm.

[0224] The carbon material may be, for example, crystalline carbon, non-graphitic carbon, or a combination thereof. The crystalline carbon may be, for example, at least one selected from natural graphite, artificial graphite, mesophase carbon microbeads, and combinations thereof. The non-graphitic carbon may be at least one selected from carbon black, activated carbon, acetylene black, Denka black, Ketjen black, furnace black, graphene, and combinations thereof.

[0225] When the above-described negative electrode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 1:2, 1:10 to 2:1, 5:1 to 1:1, or 4:1 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state battery can be improved. The above-described negative electrode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0226] The above cathode coating layer (405) may further include a binder, and the binder may be, for example, a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0227] The thickness of the negative electrode coating layer (405) may be, for example, 1 μm to 20 μm, 2 μm to 10 μm, or 3 μm to 7 μm. In addition, the thickness of the negative electrode coating layer (405) may be 50% or less, 20% or less, or 5% or less of the thickness of the positive electrode active material layer. If the thickness of the negative electrode coating layer (405) is too thin, it may be collapsed by the lithium metal layer (404), and if the thickness is too thick, the density of the all-solid-state battery may decrease and the internal resistance may increase.

[0228] The above-described precipitated negative electrode (400') may further include, for example, a thin film on the surface of the current collector, i.e., between the current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitated form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 800 nm, or 100 nm to 500 nm.

[0229] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy.

[0230] The thickness of the lithium metal layer (404) may be 1 μm to 500 μm, 1 μm to 200 μm, 1 μm to 100 μm, or 1 μm to 50 μm. If the thickness of the lithium metal layer (404) is too thin, it may be difficult to perform the role of a lithium storage, and if it is too thick, the battery volume may increase and performance may deteriorate.

[0231] When such a precipitation-type cathode is applied, the cathode coating layer (405) can play a role in protecting the lithium metal layer (404) and suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0232] solid electrolyte layer

[0233] The above solid electrolyte layer (300) includes a solid electrolyte, and the solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte or an oxide-based solid electrolyte, or a solid polymer electrolyte. A description of the types of solid electrolytes is omitted as they are as described above.

[0234] For example, the solid electrolyte included in the positive electrode (200) and the solid electrolyte included in the solid electrolyte layer (300) may include the same compound, for example, they may be the same sulfide-based solid electrolyte, for example, they may be the same argyrodite-type sulfide-based solid electrolyte. In this case, the overall performance of the all-solid-state battery may be improved and stable operation may be possible.

[0235] In addition, the average particle diameter (D50) of the solid electrolyte included in the positive electrode (200) may be smaller than the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer (300). In this case, the energy density of the all-solid-state battery can be maximized while increasing the mobility of lithium ions, thereby improving the overall performance. For example, the average particle diameter (D50) of the solid electrolyte included in the positive electrode (200) may be 0.5 ㎛ to 2.0 ㎛, or 0.5 ㎛ to 1.5 ㎛, and the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer (300) may be 2.1 ㎛ to 5.0 ㎛, or 2.1 ㎛ to 4.0 ㎛, or 2.5 ㎛ to 3.5 ㎛. When this particle size range is satisfied, the energy density of the all-solid-state battery can be maximized while lithium ion transport is facilitated, thereby suppressing resistance and improving the overall performance of the all-solid-state battery. Here, the average particle diameter (D50) of the solid electrolyte can be measured using a particle size analyzer using laser diffraction. Alternatively, the particle size can be measured by selecting approximately 30 random particles from a microscope image such as a scanning electron microscope, obtaining a particle size distribution, and calculating the D50 value from this.

[0236] The above solid electrolyte layer may further include a binder in addition to the solid electrolyte. At this time, the binder may be styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, but is not limited thereto, and any binder used in the relevant technical field may be used. The acrylate polymer may be, for example, butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0237] The above solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the same on a base film, and drying the same. The solvent of the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof, or may be a compound represented by the aforementioned chemical formula 1 and / or a compound represented by the aforementioned chemical formula 2. Since the solid electrolyte layer forming process is widely known in the art, a detailed description thereof will be omitted.

[0238] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0239] The solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0240] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

[0241] The above lithium salts include, for example, LiSCN, LiN(CN)2, Li(CF3SO2)3C, LiC4F9SO3, LiN(SO2CF2CF3)2, LiCl, LiF, LiBr, LiI, LiB(C2O4)2, LiBF4, LiBF3(C2F5), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LIODFB), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, It may include LiN(SO2F)2), LiCF3SO3, LiAsF6, LiSbF6, LiClO4 or mixtures thereof.

[0242] In addition, the lithium salt may be an imide-based one, and for example, the imide-based lithium salt may include lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, LiN(SO2F)2). The lithium salt may maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with an ionic liquid.

[0243] The above ionic liquid has a melting point below room temperature and is a salt or room-temperature molten salt that is liquid at room temperature and consists only of ions.

[0244] The above ionic liquid may be a compound including a) one or more cations selected from ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazolium-based, and mixtures thereof, and b) one or more anions selected from BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, Cl-, Br-, I-, BF4-, SO4-, CF3SO3-, (FSO2)2N-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, and (CF3SO2)2N-.

[0245] The ionic liquid may be at least one selected from the group consisting of, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0246] In the above solid electrolyte layer, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state battery can be improved.

[0247] An all-solid-state battery according to one embodiment can be manufactured by sequentially stacking a positive electrode, a solid electrolyte, and a negative electrode to prepare a layered body, and then pressurizing the stacked body.

[0248] The pressurization may be performed at a temperature of, for example, 25°C to 90°C, and at a pressure of 550 MPa or less, or 500 MPa or less, for example, 400 MPa to 500 MPa. The pressurization may be, for example, an isostatic press, a roll press, or a plate press.

[0249] The above-mentioned all-solid-state battery may be a unit battery having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode, or a laminated battery in which the structure of the unit battery is repeated.

[0250] The shape of the above-mentioned all-solid-state battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state battery can be applied to medium- to large-sized batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be applied to energy storage systems (ESS) that require a large amount of power storage, and can also be applied to electric bicycles or power tools, etc.

[0251]

[0252] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0253]

[0254] Example 1

[0255] 1. Manufacturing of the anode

[0256] LiNi coated with Li2O-ZrO2 out of a total of 100 parts by weight based on solid content 0.9 Co 0.05 Mn 0.0585 parts by weight of O2 positive electrode active material, 13.61 parts by weight of lithium argyrodite-type solid electrolyte Li6PS5Cl, 0.6 parts by weight of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) binder, 0.05 parts by weight of poly(ethylene glycol) diglycidyl ether (PEGDGE) Mn: 700), 0.4 parts by weight of carbon nanotube conductive material, and 0.16 parts by weight of dispersant were prepared, and a mixture was prepared by putting the mixture into a dispersion medium (consisting only of n-octyl acetate (OA)). The mixture was put into a thinky mixer, and 2 mm zirconia balls were added and stirred. Then, 0.1 parts by weight of lithium bis(trifluoromethane)sulfonimide salt (LiTFSI) as an electrolyte salt and 0.08 parts by weight of LiBF4 were added to prepare a positive electrode composition. At this time, the content of the dispersant is 30 parts by weight per 100 parts by weight of the solid content. The solid content represents the total of the positive electrode active material, solid electrolyte, binder, electrolyte salt, poly(ethylene glycol) diglycidyl ether, conductive agent, and dispersant.

[0257] The prepared positive electrode composition is coated on a positive electrode current collector using a bar coater, dried in a convection oven at 60°C for 10 minutes, and vacuum dried at 80°C for 4 hours, thereby manufacturing a positive electrode in which a positive electrode active material layer is formed on the current collector.

[0258] 2. Manufacturing of all-solid-state batteries

[0259] (1) Manufacturing of solid electrolyte layer

[0260] An argyrodite-type solid electrolyte Li6PS5Cl (D50=3㎛) is added to a binder solution in which an acrylic binder (SX-A334, Zeon) is dissolved in an isobutylyl isobutylate (IBIB) solvent, and the solution is stirred in a sinky mixer to adjust the viscosity to an appropriate level. After adjusting the viscosity, 2 mm zirconia balls are added and stirred again in a sinky mixer to prepare a slurry. The slurry contains 98.5 wt% of the solid electrolyte and 1.5 wt% of the acrylic binder. The slurry is applied on a release PET film using a bar coater and dried at room temperature to prepare a solid electrolyte layer.

[0261] (2) Manufacturing of cathode

[0262] A catalyst is prepared by mixing carbon black having a primary particle size (D50) of about 30 nm and silver (Ag) having an average particle size (D50) of about 60 nm in a weight ratio of 3:1, and 0.25 g of the catalyst is added to 2 g of an NMP solution containing 7 wt% of polyvinylidene fluoride binder and mixed to prepare a cathode coating layer composition. This is applied to a nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type cathode in which a cathode coating layer is formed on the current collector.

[0263] (3) Manufacturing of the final solid-state battery

[0264] The prepared positive electrode, negative electrode, and solid electrolyte layers are cut, a solid electrolyte layer is laminated on the positive electrode, and then a negative electrode is laminated on top of that. This is sealed in a pouch shape and subjected to warm isostatic pressing (WIP) at a high temperature of 85°C and 500 MPa for 30 minutes to manufacture an all-solid-state battery. In a pressurized state, the positive electrode active material layer has a thickness of approximately 100 μm, the negative electrode coating layer has a thickness of approximately 7 μm, and the solid electrolyte layer has a thickness of approximately 60 μm.

[0265] Examples 2 to 3 and Comparative Example 1

[0266] In the manufacture of anode compositions, poly(vinylidene fluoride-co(co)-hexafluoropropylene) (PVDF-HFP) binder, lithium bis(trifluoromethane)sulfonimide salt (LiTFSI), LiBF4, A positive electrode and an all-solid-state battery are manufactured in the same manner as Example 1, except that the content of each poly(ethylene glycol) diglycidyl ether is changed as shown in Table 1 (unit: parts by weight) to a total of 100 parts by weight based on solid content.

[0267] Comparative Example 2

[0268] A positive electrode and an all-solid-state battery were manufactured using the same method as Example 1, except that the composition was prepared in the same manner, coated on a positive electrode current collector using a bar coater, and dried in a convection oven at 60°C for 10 minutes, but not vacuum-dried at 80°C for 4 hours. A positive electrode and an all-solid-state battery were manufactured using the same method, except that a positive electrode in which a positive electrode active material layer was formed on a current collector was manufactured. At this time, PEGDE did not undergo a cross-linking reaction.

[0269] Comparative Example 3

[0270] A positive electrode and an all-solid-state battery are manufactured in the same manner as in Example 1, except that 0.06 parts by weight of poly(ethylene glycol) dimethyl ether (PEGDME) is included instead of poly(ethylene glycol) diglycidyl ether in the manufacture of the positive electrode composition, so that the total solid content is 100 parts by weight.

[0271] PEGDGELiTFSILiBF4PVDF-HFPPEGDMEExample 10.050.10.080.60Example 20.10.10.080.550Example 30.20.10.080.450Comparative Example 100.10.080.650Comparative Example 20.050.10.080.60Comparative Example 300.10.080.600.05

[0272] Evaluation Example: Evaluation of Charge / Discharge Capacity and Lifespan of All-Solid-State Secondary Battery

[0273] The all-solid-state secondary batteries manufactured in the examples and comparative examples were charged at a constant current of 0.1 C at 45°C to an upper limit voltage of 4.25 V and then discharged at 0.1 C to a final voltage of 2.5 V to perform an initial charge-discharge. Then, a second cycle was performed under the same voltage range with 0.1 C charge and 0.33 C discharge conditions. Thereafter, a third cycle was performed under the same voltage range with 0.1 C charge and 1.0 C discharge conditions. The results are shown in Table 2 and Fig. 3 below.

[0274] First cycleSecond cycleThird cycleCharge capacity (mAh / g)Discharge capacity (mAh / g)Efficiency (%)Charge capacity (mAh / g)Discharge capacity (mAh / g)Charge capacity (mAh / g)Discharge capacity (mAh / g)Example 1234.6210.489.7209.0196.7196.0180.8Comparative example 1239.0208.087.0206.6194.0193.3179.0Comparative example 2237.7210.888.7209.5197.4196.9182.1Comparative example 3239.1208.287.0208.1195.9195.5181.7

[0275] As shown in Table 2 and Figure 3 above, the all-solid-state battery of Example 1 had higher efficiency and superior capacity than Comparative Examples 1 and 3 in all of the first, second, and third cycles. In addition, the all-solid-state battery of Example 1 had higher efficiency in the first cycle than Comparative Example 2.

[0276]

[0277] While the preferred embodiments have been described in detail, the scope of the present invention is not limited thereto. Furthermore, it should be understood that various modifications and improvements made by those skilled in the art utilizing the basic concepts defined in the claims are also within the scope of the present invention.

Claims

1. A positive electrode for an all-solid-state battery comprising a current collector and a positive electrode active material layer positioned on the current collector, The positive electrode active material layer comprises: a positive electrode active material; a sulfide-based solid electrolyte; a dispersion medium including a compound of formula 1; a binder; an electrolyte salt; a crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture thereof; and a conductive material; [Chemical Formula 1] CH3C(=O)O-R 1 R 1 is an alkyl group of C7 to C9.

2. A positive electrode for an all-solid-state battery, wherein the binder, the electrolyte salt, and the cross-linking agent in the first paragraph are all adhesive elastomers.

3. In paragraph 1, the cross-linking agent is combined with at least one of the binder and the electrolyte salt, and is a positive electrode for an all-solid-state battery.

4. In the first paragraph, the crosslinker forms a semi-IPN structure together with the binder, and is a positive electrode for an all-solid-state battery.

5. A positive electrode for an all-solid-state battery, wherein the cross-linking agent in paragraph 1 is contained in an amount of 1 to 30 wt% of the total of the binder, the electrolyte salt, and the cross-linking agent.

6. A positive electrode for an all-solid-state battery, wherein the cross-linking agent in paragraph 1 is contained in an amount of 0.001 to 1 wt% of the positive electrode active material layer.

7. In paragraph 1, the bifunctional or higher glycidyl ether compound having an alkylene glycol group includes at least one compound represented by the following chemical formula 4, a positive electrode for an all-solid-state battery: [Chemical Formula 4] (In the above chemical formula 4, R 4 is a straight or branched alkylene group having 1 to 5 carbon atoms. R 5 and R 6 are each independently a single bond or an alkylene group having 1 to 5 carbon atoms, n is an integer between 2 and 1000).

8. A positive electrode for an all-solid-state battery, wherein the bifunctional or higher glycidyl ether compound having an alkylene glycol group in paragraph 1 comprises at least one poly(ethylene glycol) diglycidyl ether.

9. In paragraph 1, the mixture comprises a difunctional or higher glycidyl ether compound having an alkylene glycol group and a difunctional or higher amine compound having an alkylene glycol group. A positive electrode for an all-solid-state battery.

10. In paragraph 9, the bifunctional or higher amine compound having the alkylene glycol group includes a compound of the following chemical formula 6, an all-solid-state battery positive electrode: [Chemical Formula 6] (In the above chemical formula 6, R 7 A straight or branched alkylene group having 1 to 5 carbon atoms R 8 is a single bond or an alkylene group having 1 to 5 carbon atoms, n is an integer between 2 and 1000).

11. A positive electrode for an all-solid-state battery, wherein the electrolyte salt in paragraph 1 is a fluorine-containing lithium salt.

12. In paragraph 1, the binder comprises at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, styrene butadiene rubber, polyacrylonitrile, and polymethyl(meth)acrylate, a positive electrode for an all-solid-state battery.

13. A positive electrode for an all-solid-state battery, wherein in paragraph 1, the binder is a polyvinylidene fluoride-hexafluoropropylene copolymer, the electrolyte salt is a combination of a perfluoroalkanesulfonyl imide salt and an inorganic fluoride salt, and the bifunctional or higher glycidyl ether compound having an alkylene glycol group is poly(ethylene glycol) diglycidyl ether.

14. In paragraph 1, the positive electrode active material layer 55 wt% to 99 wt% of positive electrode active material; 0.1 wt% to 35 wt% of sulfide-based solid electrolyte; Binder 0.1 wt% to 5 wt%; 0.001 wt% to 10 wt% of electrolyte salt; 0.001 wt% to 1 wt% of a crosslinked product of a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture containing the same; An all-solid-state battery positive electrode comprising 0.1 to 5 wt% of a conductive agent.

15. A preliminary composition comprising a positive electrode active material; a sulfide-based solid electrolyte; a dispersion medium comprising a compound of formula 1; a binder; a bifunctional or higher glycidyl ether compound having an alkylene glycol group or a mixture comprising the same; and a conductive material is prepared. A method for producing a positive electrode composition for an all-solid-state battery, comprising the step of adding an electrolyte salt to the above-mentioned preliminary composition.

16. The anode according to any one of paragraphs 1 to 14; Cathode and An all-solid-state battery comprising a solid electrolyte layer positioned between the positive electrode and the negative electrode.

17. In paragraph 15, an all-solid-state battery comprising a current collector and a negative electrode coating layer positioned on the current collector, and a lithium metal layer formed between the current collector and the negative electrode coating layer during initial charging.

18. In paragraph 15, an all-solid-state battery wherein the solid electrolyte included in the positive electrode and the solid electrolyte included in the solid electrolyte layer contain the same compound.

19. In paragraph 15, an all-solid-state battery in which the average particle diameter (D50) of the solid electrolyte included in the positive electrode is smaller than the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer, the average particle diameter (D50) of the solid electrolyte included in the positive electrode is 0.5 ㎛ to 2.0 ㎛, and the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer is 2.1 ㎛ to 5.0 ㎛.

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