Solid electrolyte membrane, electrode, and all-solid-state rechargeable battery

Abstract

The present invention relates to a solid electrolyte membrane, an electrode, and an all-solid-state secondary battery, the solid electrolyte membrane comprising a sulfide-based solid electrolyte and an additive, wherein the additive comprises a compound represented by chemical formula 1. The definition of chemical formula 1 is as described in the specification.

Description

Solid electrolyte membranes, electrodes, and all-solid-state secondary batteries

[0001] It relates to a solid electrolyte membrane, electrode, and an all-solid-state secondary battery.

[0002] 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. Recently, active research is underway to utilize high-energy-density lithium secondary batteries as power sources for hybrid and electric vehicles, or as power storage devices.

[0003] Commercially available lithium secondary batteries use electrolytes containing flammable organic solvents, posing safety concerns that can lead to explosion or fire in the event of collisions, penetration, or other problems. Therefore, all-solid-state secondary batteries, which utilize solid electrolytes instead of the electrolyte, have been proposed. All-solid-state secondary batteries are composed entirely of solid materials, eliminating the risk of electrolyte leakage and explosion, making them safer. Furthermore, they facilitate the production of thin batteries, allowing for a reduced anode thickness, improving high-speed charge / discharge performance and enabling high-voltage operation and high-energy density.

[0004] Provided are a solid electrolyte membrane and electrodes that can form a film at high temperatures to block ionic current and induce shutdown of the battery in the event of an abnormal reaction in an all-solid-state secondary battery, and provide an all-solid-state secondary battery with improved safety and reliability.

[0005] In one embodiment, a solid electrolyte membrane is provided, which comprises a sulfide-based solid electrolyte and an additive, wherein the additive comprises a compound represented by the following chemical formula 1.

[0006] [Chemical Formula 1]

[0007]

[0008] In chemical formula 1,

[0009] A is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof,

[0010] In SX, S stands for Sulfur,

[0011] X is hydrogen, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Ba, Cu, Zn, Ag, In, Sb, Co, Fe, Mn, or Pd,

[0012] R 1 Inland R 4 are the same or different from each other, and each independently represents hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkenyl group, a substituted or unsubstituted C2 to C20 heterocycloalkynyl group, a substituted or unsubstituted C3 to C20 heteroaryl group, a substituted or unsubstituted C1 to C20 alkoxy group, an ester group, an ether group, a carboxyl group or a salt thereof, a cyano group, A carbonyl group, an imino group, a halogen group, N, O, S, P, Si, B, or a combination thereof.

[0013] In another embodiment, an electrode for an all-solid-state secondary battery is provided, comprising an electrode active material, solid electrolyte particles, and an additive represented by Chemical Formula 1. Chemical Formula 1 is described below.

[0014] In another embodiment, an all-solid-state secondary battery is provided, comprising a positive electrode, a negative electrode, and a solid electrolyte membrane positioned between the positive electrode and the negative electrode.

[0015] According to one embodiment, a solid electrolyte membrane and electrode can form a film when the temperature rises due to an abnormal reaction of the battery, thereby blocking ionic current and inducing shutdown of the battery, thereby improving the safety and reliability of the all-solid-state secondary battery.

[0016] Figures 1 and 2 are cross-sectional views schematically showing an all-solid-state secondary battery according to one embodiment.

[0017] Figure 3 is a differential scanning calorimetry (DSC) graph for Reference Example 1.

[0018] Below, specific implementation examples are described in detail so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in various different forms and is not limited to the implementation examples described herein.

[0019] 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.

[0020] Here, “combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The average particle size can be measured by methods well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with transmission electron microscope images or scanning electron microscope images. Alternatively, the average particle size can be obtained by measuring using dynamic light scattering, performing data analysis, counting the number of particles for each particle size range, and calculating from the counted number. Unless otherwise defined, the average particle size is the diameter (D) of the particles in the particle size distribution that have a cumulative volume of 50% by volume. 50 ) can mean. In addition, unless otherwise defined, the average particle size is obtained by measuring the size (diameter or length of major axis) of about 20 particles randomly in a scanning electron microscope image to obtain a particle size distribution, and the diameter (D) of the particle having a cumulative volume of 50% by volume in the particle size distribution 50 ) may be taken as the average particle diameter.

[0025] Here, "or" is not interpreted in an exclusive sense, for example, "A or B" is interpreted to include A, B, A+B, etc.

[0026] "Metal" is interpreted as a concept that includes ordinary metals, transition metals, and metalloids (semi-metals).

[0027] "Substitution" means that at least one hydrogen atom is substituted with a halogen atom (F, Cl, Br, I), a hydroxy group, a C1 to C20 alkoxy group, a nitro group, a cyano group, an amine group, an imino group, an azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl group, a thiol group, an ester group, an ether group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C20 aryl group, a C3 to C20 cycloalkyl group, a C3 to C20 cycloalkenyl group, a C3 to C20 cycloalkynyl group, a C2 to C20 heterocycloalkyl group, a C2 to C20 heterocycloalkenyl group, a C2 to C20 It means substituted with a heterocycloalkynyl group, a C3 to C20 heteroaryl group, or a combination thereof.

[0028] solid electrolyte membrane

[0029] In one embodiment, a solid electrolyte membrane is provided, comprising a sulfide-based solid electrolyte and an additive, wherein the additive comprises a compound represented by Chemical Formula 1.

[0030] additives

[0031] The above additive can induce shutdown by blocking the ion current by forming a film through a polymerization reaction or the like when the temperature rises due to Joule heat in situations such as penetration or short circuit of the battery.

[0032] The additive can initiate a film-forming reaction at, for example, 110°C or higher or 120°C or higher, and can effectively suppress the desorption or penetration of liquid lithium by forming a film at a temperature lower than 180°C, which is the melting point of lithium metal.

[0033] The temperature at which the additive forms a film may be from 110°C to 180°C, for example from 120°C to 180°C, from 140°C to 170°C, or from 160°C to 170°C. The additive may be referred to as a film-forming additive or a shutdown additive.

[0034] The additive has little reactivity with the sulfide-based solid electrolyte within the solid electrolyte membrane, so it does not deteriorate the solid electrolyte, and even a small amount can form a film, so it can improve high-temperature safety without lowering the ionic conductivity of the solid electrolyte membrane or reducing its performance. The additive can be dispersed within the solid electrolyte membrane, and under normal or battery operation, it can act as a kind of dispersant within the solid electrolyte membrane, or it can have no effect at all, but when the battery is exposed to high-temperature conditions due to an abnormal reaction, it can form a film and perform a shutdown function.

[0035] Chemical formula 1 is as follows.

[0036] [Chemical Formula 1]

[0037]

[0038] In chemical formula 1,

[0039] A is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof,

[0040] In SX, S is sulfur, X is hydrogen, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Ba, Cu, Zn, Ag, In, Sb, Co, Fe, Mn, or Pd,

[0041] R 1 Inland R 4are the same or different from each other, and each independently represents hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkenyl group, a substituted or unsubstituted C2 to C20 heterocycloalkynyl group, a substituted or unsubstituted C3 to C20 heteroaryl group, a substituted or unsubstituted C1 to C20 alkoxy group, an ester group, an ether group, a carboxyl group or a salt thereof, a cyano group, A carbonyl group, an imino group, a halogen group (e.g., F, Cl, Br, or I), N, O, S, P, Si, B, or a combination thereof.

[0042] For example, A may be a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof, for example, a substituted or unsubstituted C6 to C20 arylene group. For example, A may be a phenylene group or a naphthalene group.

[0043] For example, the X may be hydrogen, Li, Na, K, Rb, Cs, or Fr, for example, hydrogen, Li, Na, or K.

[0044] The compound represented by Chemical Formula 1 may be lithiated or sodium-hydrated, and thus may contain lithium ions or sodium ions. In Chemical Formula 1, X may be hydrogen, lithium, or sodium. Some of X in Chemical Formula 1 may be hydrogen, and the remaining some may be lithium or sodium. Alternatively, the compound represented by Chemical Formula 1 and a lithium salt may be mixed in the solid electrolyte, and the compound represented by Chemical Formula 1 and a sodium salt may be mixed in the solid electrolyte. The lithiated or sodium-hydrated additive can further improve the ionic conductivity of the solid electrolyte membrane.

[0045] For example, the above R 1 Inland R 4 are the same or different from each other, and each independently may be hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, a halogen group, N, O, S, P, Si, B, or a combination thereof, for example, each independently may be hydrogen, or a substituted or unsubstituted C1 to C20 alkyl group.

[0046] As a specific example, the above A is a substituted or unsubstituted C6 to C20 arylene group, the above X is hydrogen, Li or Na, and the above R 1 Inland R 4 are the same or different from each other, and each independently may be hydrogen, or a substituted or unsubstituted C1 to C20 alkyl group.

[0047] For example, the additive can form a film in a temperature range of 110°C to 180°C, for example, 120°C to 180°C, 130°C to 180°C, 140°C to 180°C, or 150°C to 170°C.

[0048] The compound represented by the above chemical formula 1 can undergo a retro-Diels-Alder reaction, which is a thermal decomposition reaction, at a high temperature condition of 110°C to 180°C, and be decomposed into a conjugated diene compound represented by the following chemical formula 2 and an alkene compound of the maleimide type represented by the following chemical formula 3.

[0049] At this time, the thermal decomposition temperature may vary depending on the type of A in the chemical formula 1.

[0050] [Chemical Formula 2]

[0051]

[0052] [Chemical Formula 3]

[0053]

[0054] The maleimide compound represented by the above chemical formula 3 is an unstable compound having a maleimide moiety having a (+) and an SX moiety having a (-), and the maleimide moiety and the SX moiety continuously click react to form a polymer, and this polymer can form a film in a solid electrolyte membrane.

[0055] In addition, at high temperatures, the maleimide compound represented by the above chemical formula 3 reacts with -SH on the surface of the argyrodite-type sulfide-based solid electrolyte, thereby rapidly reducing the ionic conductivity of the solid electrolyte and inducing a shutdown, thereby improving the safety of the battery.

[0056] For example, a solid electrolyte membrane according to one embodiment may include a film comprising a polymer represented by the following chemical formula 4.

[0057] [Chemical Formula 4]

[0058]

[0059] In chemical formula 4, A may be a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof,

[0060] S is sulfur, X can be hydrogen, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Ba, Cu, Zn, Ag, In, Sb, Co, Fe, Mn, or Pd,

[0061] n can be an integer from 2 to 500.

[0062] For example, A may be a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof, for example, a substituted or unsubstituted C6 to C20 arylene group.

[0063] For example, the X may be hydrogen, Li, Na, K, Rb, Cs, or Fr, for example, hydrogen, Li, or Na.

[0064] As a specific example, A may be a substituted or unsubstituted C6 to C20 arylene group, and X may be hydrogen, Li, Na, or K.

[0065] Meanwhile, in chemical formula 4, n means the number of repetitions of the repeating unit in the polymer, and is not particularly limited, but may be, for example, an integer of 2 to 500, an integer of 3 to 400, an integer of 4 to 300, an integer of 5 to 200, an integer of 10 to 100, an integer of 10 to 50, or an integer of 2 to 20.

[0066] For example, the additive may be included in an amount of 1 wt% to 10 wt% based on 100 wt% of the solid electrolyte membrane, for example, 1 wt% to 5 wt%, or 3 wt% to 5 wt%. When the above content range is satisfied, a film can be effectively formed under high-temperature conditions without impairing the performance of the solid electrolyte membrane.

[0067] Sulfide-based solid electrolyte

[0068] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiY (where Y 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), or a combination thereof.

[0069] Such sulfide-based solid electrolytes 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, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0070] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0071] According to one embodiment, sulfide-based solid electrolyte particles can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0072] For example, the sulfide-based solid electrolyte particles may include argyrodite-type sulfides. The argyrodite-type sulfide-based solid electrolyte particles may have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It has a high ionic conductivity approaching the S / cm range, can form a close bond between a positive electrode active material and a solid electrolyte without causing a decrease in ionic conductivity, and can further form a close interface between an electrode layer and a solid electrolyte layer. An all-solid-state secondary battery including the same can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0073] The argyrodite-type sulfide-based solid electrolyte particles may include, for example, a compound represented by the chemical formula 5 below.

[0074] [Chemical Formula 5]

[0075] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )Y h

[0076] In the above chemical formula 5, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and Y is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0077] For example, in chemical formula 5, a halide element (Y) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 5에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 5에서 M 3 can be understood as an element substituted in place of P and 0 <e<1일 수 있다. 화학식 5에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며 S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0078] For example, in chemical formula 5, a+b+c+h=7, d+e=1, and f+g+h=6.

[0079] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu 0.06)P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0080] An argyrodite-type sulfide-based solid electrolyte can be manufactured, for example, by mixing lithium sulfide and phosphorus sulfide, and optionally, lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the resultant of the first heat treatment again and calcining at 350°C to 800°C.

[0081] Average particle diameter (D) of sulfide-based solid electrolyte particles 50) may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, and may be small particles of 0.1 ㎛ to 1.9 ㎛ or large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle diameter of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle diameter of 2.0 ㎛ to 5.0 ㎛. The average particle diameter of the sulfide-based solid electrolyte particles may be measured from an electron microscope image, and for example, the particle size distribution may be obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, and D50 may be calculated from this.

[0082] bookbinder

[0083] A solid electrolyte membrane according to one embodiment may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane, and the like. copolymers, or combinations thereof.

[0084] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte membrane, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte membrane can be well combined without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0085] Other ingredients

[0086] The solid electrolyte membrane may include an oxide-based inorganic solid electrolyte in addition to a sulfide-based solid electrolyte. The oxide-based inorganic solid electrolyte may include, for example, 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.

[0087] The solid electrolyte membrane may further include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halide element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0088] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li a M1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte is, for example, Li2ZrCl6, Li 2.7 Y 0.7 Zr 0.3 Cl6, Li 2.5 Y0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0089] The solid electrolyte membrane may optionally further comprise an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0090] 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.

[0091] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0092] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0093] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0094] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) 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 - It may be a compound containing one or more anions selected from among.

[0095] 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.

[0096] 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 secondary battery can be improved.

[0097]

[0098] One embodiment provides an electrode for an all-solid-state secondary battery comprising an electrode active material, solid electrolyte particles, and an additive represented by the above-described chemical formula 1.

[0099] When the additive described above is included in the electrode in addition to the solid electrolyte membrane, the safety of the battery can be improved by forming a film on the electrode through a polymerization reaction of the additive when the temperature rises due to heat at high temperature, or by inducing a shutdown by rapidly reducing the ionic conductivity of the solid electrolyte through a reaction between the additive and the solid electrolyte particles.

[0100] The above additive may be included in an amount of 1 wt% to 10 wt% based on 100 wt% of the electrode, for example, 1 wt% to 5 wt%, or 3 wt% to 5 wt%. When the above content range is satisfied, a film can be effectively formed under high temperature conditions without deteriorating electrode performance.

[0101] The electrode may be, for example, a positive electrode, and in one embodiment, a positive electrode for an all-solid-state secondary battery may be provided, which includes a positive electrode active material, solid electrolyte particles, and an additive represented by Chemical Formula 1. As another example, the electrode may be a negative electrode, and thus a negative electrode for an all-solid-state secondary battery may be provided, which includes a negative electrode active material, solid electrolyte particles, and an additive represented by Chemical Formula 1.

[0102] Since the above additives are the same as those described above, detailed descriptions are omitted here.

[0103] anode

[0104] In one embodiment, the current collector includes a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer includes a positive electrode active material and a solid electrolyte, and may optionally include a binder and / or a conductive material, and may optionally include an additive represented by the aforementioned chemical formula 1. In this case, the positive electrode active material layer may include the aforementioned solid electrolyte.

[0105] positive electrode active material

[0106] The above-mentioned positive electrode active material may be applied without limitation as long as it is generally used in all-solid-state secondary batteries. For example, the above-mentioned positive electrode active material may be a compound capable of reversible intercalation and deintercalation of lithium, may include a lithium transition metal composite oxide, and may include a compound represented by any one of the following chemical formulas.

[0107] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0108] 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);

[0109] Li a HAVE BEEN 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0110] Li a HAVE BEEN 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0111] 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);

[0112] 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);

[0113] Li a Ni 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);

[0114] Li a Ni 1-b-c Mr b X c D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2);

[0115] Li a Ni1-b-c Mr b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0116] Li a Ni 1-b-c Mr b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0117] Li a Ni b HAVE BEEN c G d O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1);

[0118] Li a Ni b Co c Mr 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);

[0119] Li a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0120] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0121] Li a Mr 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0122] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0123] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0124] QO2; QS2; LiQS2;

[0125] V2O5; LiV2O5;

[0126] LiZO2;

[0127] LiNiVO4;

[0128] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0129] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0130] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0131] 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.

[0132] The above-mentioned positive electrode active material may be, 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 nickel manganese oxide (NM), lithium manganese oxide (LMO), or lithium iron phosphate (LFP).

[0133] The positive electrode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 6, a lithium cobalt-based oxide represented by the following chemical formula 7, a lithium iron phosphate-based compound represented by the following chemical formula 8, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 9, or a combination thereof.

[0134] [Chemical Formula 6]

[0135] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0136] In the above chemical formula 6, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0137] In the above chemical formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0138] [Chemical Formula 7]

[0139] Li a2 Cox2 M 3 y2 O 2-b2 X b2

[0140] In the above chemical formula 7, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0141] [Chemical Formula 8]

[0142] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0143] In the above chemical formula 8, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0144] [Chemical Formula 9]

[0145] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0146] In the above chemical formula 9, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0147] The average particle diameter (D) of the above positive electrode active material 50 ) may be 1 ㎛ to 25 ㎛, for example, 3 ㎛ to 25 ㎛, 1 ㎛ to 20 ㎛, 1 ㎛ to 18 ㎛, 3 ㎛ to 15 ㎛, or 5 ㎛ to 15 ㎛. For example, the positive electrode active material may have an average particle diameter (D 50 ) with small particles of 1 ㎛ to 9 ㎛ and an average particle diameter (D 50 ) may include particles having a particle size range of 10 ㎛ to 25 ㎛. The positive electrode active material having such a particle size range can be harmoniously mixed with other components in the positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle size is obtained by selecting 20 or so random particles from a scanning electron microscope image of the positive electrode active material, measuring their particle sizes (diameter, or major axis, or major axis length), and then obtaining a particle size distribution, and in the particle size distribution, the diameter (D) of the particles having a cumulative volume of 50% by volume 50 ) may be taken as the average particle diameter.

[0148] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0149] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be one or more elements selected from the group consisting of Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, and Zr. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles while improving the performance of the positive electrode active material by facilitating the movement of lithium ions and electron conduction.

[0150] The positive electrode active material may be included in an amount of 55 wt% to 99 wt% based on 100 wt% of the positive electrode active material layer, for example, 65 wt% to 95 wt%, or 75 wt% to 91 wt%.

[0151] bookbinder

[0152] The above binder serves to adhere the positive electrode active material particles well to each other and also to adhere the positive electrode active material well to the current collector, and representative examples thereof 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, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0153] The content of the binder in the positive electrode active material layer may be approximately 0.1 wt% to 5 wt% with respect to 100 wt% of the positive electrode active material layer.

[0154] Challenge

[0155] The above-described positive electrode active material layer may further include a conductive material. The conductive material is used to provide conductivity to the electrode, and any material that does not cause a chemical change and is electronically conductive in the battery to be constructed may be used. Examples of conductive materials that may be used include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0156] The content of the conductive material in the positive electrode active material layer may be 0 wt% to 3 wt%, 0.01 wt% to 2 wt%, or 0.1 wt% to 1 wt% with respect to 100 wt% of the positive electrode active material layer.

[0157] With respect to 100 wt% of the above positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0158] 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.

[0159] Aluminum foil may be used as the positive electrode current collector, but is not limited thereto.

[0160] cathode

[0161] An anode for an all-solid-state secondary battery comprises a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer comprises a negative electrode active material, may further comprise a binder and / or a conductive material, may optionally comprise the aforementioned solid electrolyte, and may optionally comprise an additive represented by the aforementioned chemical formula 1.

[0162] The above negative electrode active material includes 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.

[0163] 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.

[0164] As the above lithium metal alloy, an alloy of lithium and a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0165] 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 alloy (wherein Q is an element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof, and is not Si), Sn-based negative electrode active materials include Sn, SnO2, Sn-R alloy (wherein R is an element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof, and is not Sn), and at least one of these may be mixed with SiO2 for use. The above elements Q and R may be selected from the group consisting of 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, and combinations thereof.

[0166] For example, the negative active material may include silicon-carbon composite particles. The average particle diameter (D) of the silicon-carbon composite particles 50 ) may be, for example, 0.5 ㎛ to 20 ㎛. The average particle diameter (D 50 ) is measured by a particle size analyzer and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution. With respect to 100 wt% of the silicon-carbon composite particles, silicon may be included in an amount of 10 wt% to 60 wt% and carbon may be included in an amount of 40 wt% to 90 wt%. The silicon-carbon composite particles may include, for example, a core including silicon particles, and a carbon coating layer located on the surface of the core. The average particle diameter (D) of the silicon particles in the core 50) may be 10 nm to 1 ㎛, or 10 nm to 200 nm. The silicon particles may exist as silicon alone, in the form of a silicon alloy, or in an oxidized form. The oxidized form of silicon is SiO x (0 <x<2)로 표시될 수 있다. 또한, 상기 탄소 코팅층의 두께는 약 5 nm 내지 100 nm일 수 있다.

[0167] For example, the silicon-carbon composite particle may include a core including silicon particles and crystalline carbon, and a carbon coating layer located on the surface of the core and including amorphous carbon. For example, in the silicon-carbon composite particle, the amorphous carbon may not be present in the core but may be present only in the carbon coating layer. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof, and the amorphous carbon may be formed from coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin (phenol resin, furan resin, polyimide resin, etc.). At this time, the content of the crystalline carbon may be 10 wt% to 70 wt%, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to 100 wt% of the silicon-carbon composite particle.

[0168] In the above silicon-carbon composite particle, the core may include a void in the central portion. The radius of the void may be 30% to 50% of the radius of the silicon-carbon composite particle.

[0169] The silicon-carbon composite particles described above can effectively suppress problems such as volume expansion, structural collapse, or particle crushing due to charge and discharge, thereby preventing the phenomenon of conductive path disconnection, realizing high capacity and high efficiency, and are advantageous for use under high voltage or fast charging conditions.

[0170] 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. When the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material are used in combination, the mixing ratio can be 1:99 to 90:10 by weight.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] When a water-soluble binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity as a type of thickener 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 the thickener used may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0177] The above conductive material is used to provide conductivity to the electrode, and in the battery to be formed, any material that does not cause a chemical change and is electronically conductive can be used. Examples of conductive materials that can be used include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials including copper, nickel, aluminum, silver, etc. and in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0178] The negative electrode current collector may be selected from the group consisting of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0179] As another example, the negative electrode for an all-solid-state secondary battery may be a precipitation-type negative electrode. The precipitation-type negative electrode may refer to a negative electrode that does not include a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated or deposited on the negative electrode when the battery is charged, and this acts as a negative electrode active material.

[0180] Fig. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode. Referring to Fig. 2, the precipitation-type 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 secondary battery including such a precipitation-type negative electrode (400') starts initial charging in a state in which no negative electrode active material is present, and during charging, high-density lithium metal is precipitated or deposited between the current collector (401) and the negative electrode coating layer (405) or on 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 secondary battery that has been charged more than once, the precipitation-type negative electrode (400') may include, for example, 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 lithium metal layer (404) refers to a layer in which lithium metal or the like is precipitated during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium deposition layer, or a negative electrode active material layer.

[0181] In this case, the aforementioned area or first solid electrolyte layer can be said to be a surface in contact with the cathode coating layer (405).

[0182] The above cathode coating layer (405) may be referred to as a lithium electrodeposition induction layer or a cathode catalyst layer, and may include a metal, carbon material, or a combination thereof that acts as a catalyst.

[0183] The metal may be a lithium-philic metal, and may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one type of these or may be composed of several types of alloys. When the metal is present in the form of particles, the average particle diameter (D50) thereof may be about 4 μm or less, and may be, for example, 10 nm to 4 μm.

[0184] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0185] 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 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state secondary 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.

[0186] The above-described cathode coating layer (405) may include, for example, the above-described lithium-philic metal and amorphous carbon, in which case the precipitation of the lithium metal may be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-philic metal is supported on amorphous carbon.

[0187] 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.

[0188] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 ㎛, or 500 nm to 10 ㎛, or 1 ㎛ to 5 ㎛.

[0189] 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 secondary 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 500 nm.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] All-solid-state secondary battery

[0194] In one embodiment, an all-solid-state secondary battery is provided, comprising a positive electrode, a negative electrode, and a solid electrolyte membrane positioned between the positive electrode and the negative electrode. At least one of the positive electrode, the negative electrode, and the solid electrolyte membrane may include an additive represented by the aforementioned chemical formula 1.

[0195] FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to an embodiment. Referring to FIG. 1, the all-solid-state secondary 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 battery case. The all-solid-state secondary 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 secondary battery may be manufactured by laminating two or more electrode assemblies.

[0196] The above-mentioned all-solid-state secondary battery may be a unit cell having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of negative electrode / solid electrolyte layer / positive electrode / solid electrolyte layer / negative electrode, or a laminated battery in which the structure of the unit cell is repeated.

[0197] The shape of the above-mentioned all-solid-state secondary 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 secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0198] 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.

[0199] Evaluation Example 1

[0200] For the crosslinking polymerization reaction test, Reference Example 1 is prepared by adding a compound represented by the following chemical formula 1-1 as an additive to isobutyryl isobutyrate (IBIB) solvent.

[0201] [Chemical Formula 1-1]

[0202]

[0203] Differential scanning calorimetry (DSC) was performed on Reference Example 1, and the results are shown in Fig. 3. Referring to Fig. 3, it can be seen that in the case of Reference Example 1, a thermal decomposition reaction begins between about 80°C and about 125°C, and a film is formed between about 180°C and about 205°C. That is, it can be seen that Reference Example 1 undergoes a polymerization reaction under high temperature conditions of about 110°C to about 180°C to form a film.

[0204] Comparative Example 1

[0205] A composition for a solid electrolyte membrane is prepared by adding 2 wt% of an acrylic copolymer binder (SX-A334, Zeon) and 98 wt% of a solid electrolyte (Li6PS5Cl, D50=3.5㎛) to an IBIB solvent and mixing them. The composition is applied onto a release PET film using a blade coater, pre-dried at about 50°C, and then dried at about 70°C under vacuum conditions to prepare a solid electrolyte membrane having a thickness of about 200㎛.

[0206] Example 1

[0207] When manufacturing a solid electrolyte membrane, a solid electrolyte membrane is manufactured in substantially the same manner as in Comparative Example 1, except that 2 wt% of binder, 5 wt% of the additive (chemical formula 1-1) used in Reference Example 1, and 93 wt% of the solid electrolyte are mixed.

[0208] Evaluation Example 2

[0209] An experiment was conducted in which the solid electrolyte membranes manufactured in Comparative Example 1 and Example 1 were heated at 130°C for 15 minutes, and the change in ionic conductivity before and after heating was measured, and the results are shown in Table 1 below. The ionic conductivity was measured through electrochemical impedance spectroscopy (EIS), and EIS was performed at an amplitude of approximately 10 mV, a frequency of 0.001 Hz to 0.1 Hz, in an air atmosphere, and at 25°C.

[0210] Lithium ion conductivity (mS / cm) Preheating Postheating Comparative Example 10.530.51 Example 10.45-

[0211] (In Table 1 above, '-' means that the ionic conductivity is so low that it cannot be measured.) Referring to Table 1, in the case of Example 1, it can be confirmed that a film is formed within the solid electrolyte membrane when heated at 130°C, thereby inducing a shutdown and successfully reducing the ionic conductivity. On the other hand, in the case of Comparative Example 1, a film is not formed even after heating at 130°C, so a shutdown is not induced, and thus it can be confirmed that there is almost no change in the ionic conductivity.

[0212] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

[0213] <Explanation of symbols>

[0214] 100: All-solid-state battery 200: Cathode

[0215] 201: Cathode current collector 203: Cathode active material layer

[0216] 300: Solid electrolyte layer 400: Cathode

[0217] 401: Negative current collector 403: Negative active material layer

[0218] 400': Precipitation type cathode 404: Lithium metal layer

[0219] 405: Cathode coating layer 500: Elastic layer

Claims

1. Contains a sulfide-based solid electrolyte and additives; The above additive is a solid electrolyte membrane comprising a compound represented by the following chemical formula 1: [Chemical Formula 1] In chemical formula 1, A is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof, In SX, S stands for Sulfur, X is hydrogen, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Ba, Cu, Zn, Ag, In, Sb, Co, Fe, Mn, or Pd, R 1 Inland R 4 are the same as or different from each other, and each independently represents hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkenyl group, a substituted or unsubstituted C2 to C20 heterocycloalkynyl group, a substituted or unsubstituted C3 to C20 heteroaryl group, a substituted or unsubstituted C1 to C20 alkoxy group, an ester group, an ether group, a carboxyl group or a salt thereof, a cyano group, A carbonyl group, an imino group, a halogen group, N, O, S, P, Si, B, or a combination thereof.

2. In paragraph 1, A solid electrolyte membrane, wherein in the chemical formula 1, A is a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof.

3. In paragraph 1, A solid electrolyte membrane, wherein in the chemical formula 1, X is hydrogen, Li, Na, or K.

4. In paragraph 1, In the chemical formula 1 above, R 1 Inland R 4 A solid electrolyte membrane, wherein are the same or different from each other, and each independently represents hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, a halogen group, N, O, S, P, Si, B, or a combination thereof.

5. In paragraph 1, In the above chemical formula 1, The above A is a substituted or unsubstituted C6 to C20 arylene group, wherein X is hydrogen, Li or Na, Above R 1 Inland R 4 A solid electrolyte membrane, wherein are the same or different from each other, and each independently represents hydrogen, or a substituted or unsubstituted C1 to C20 alkyl group.

6. In paragraph 1, A solid electrolyte membrane, wherein the additive forms a film in a temperature range of 110°C to 180°C.

7. In paragraph 1, A solid electrolyte membrane, wherein the additive is contained in an amount of 1 wt% to 10 wt% based on 100 wt% of the solid electrolyte membrane.

8. In paragraph 1, A solid electrolyte membrane, wherein the additive is contained in an amount of 1 to 5 wt% based on 100 wt% of the solid electrolyte membrane.

9. In paragraph 1, The solid electrolyte membrane comprises a film including a polymer represented by the following chemical formula 4: [Chemical Formula 4] In chemical formula 4, A is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof, S is Sulfur, X is hydrogen, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Ba, Cu, Zn, Ag, In, Sb, Co, Fe, Mn, or Pd, n is an integer between 2 and 500.

10. In Article 9, A solid electrolyte membrane, wherein in the chemical formula 4, A is a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof.

11. In Article 9, A solid electrolyte membrane, wherein in the chemical formula 4, X is hydrogen, Li, Na, or K.

12. In paragraph 9, In the above chemical formula 4, The above A is a substituted or unsubstituted C6 to C20 arylene group, A solid electrolyte membrane, wherein X is hydrogen, Li or Na.

13. In paragraph 1, The above sulfide-based solid electrolyte is in the form of particles and has an average particle diameter (D 50 ) is a solid electrolyte membrane having a thickness of 0.1 ㎛ to 5.0 ㎛.

14. In paragraph 1, The above sulfide-based solid electrolyte is a solid electrolyte membrane containing an argyrodite-type sulfide represented by the chemical formula 5 below: [Chemical Formula 5] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )Y h In the above chemical formula 5, 4≤a≤8, M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, M 2 is Na, K, or a combination thereof, and 0≤c<0.5, M 3 is Sn, Zn, Si, Sb, Ge, or a combination of these, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, Y is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

15. Electrode active material, Sulfide-based solid electrolyte particles, and An electrode for an all-solid-state secondary battery, comprising an additive represented by the following chemical formula 1: [Chemical Formula 1] In chemical formula 1, A is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C6 to C20 heteroarylene group, or a combination thereof, In SX, S stands for Sulfur, X is hydrogen, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Ba, Cu, Zn, Ag, In, Sb, Co, Fe, Mn, or Pd, R 1 Inland R 4 are the same as or different from each other, and each independently represents hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkenyl group, a substituted or unsubstituted C2 to C20 heterocycloalkynyl group, a substituted or unsubstituted C3 to C20 heteroaryl group, a substituted or unsubstituted C1 to C20 alkoxy group, an ester group, an ether group, a carboxyl group or a salt thereof, a cyano group, A carbonyl group, an imino group, a halogen group, N, O, S, P, Si, B, or a combination thereof.

16. In paragraph 15, An electrode for an all-solid-state secondary battery, wherein the additive is contained in an amount of 1 to 10 wt% based on 100 wt% of the electrode.

17. Bipolar, cathode, and An all-solid-state secondary battery comprising a solid electrolyte membrane according to any one of claims 1 to 14 positioned between a positive electrode and a negative electrode.

18. In Article 17, The above negative electrode comprises a current collector and a negative electrode coating layer positioned on the current collector and containing a lithium-philic metal, a carbon material, or a combination thereof, An all-solid-state secondary battery comprising a lithium metal layer formed by charging between the above-described collector and the negative electrode coating layer.

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