Binder for positive electrode of all-solid-state battery, and composite positive electrode and all-solid-state battery comprising same

Abstract

The present invention relates to a binder for a positive electrode of an all-solid-state battery, and a composite positive electrode and an all-solid-state battery comprising same.

Description

Binder for positive electrode of all-solid-state battery, composite positive electrode and all-solid-state battery containing same

[0001] The present invention relates to a binder for a positive electrode of an all-solid-state battery, a composite positive electrode including the same, and an all-solid-state battery.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0117967, filed September 5, 2023, and Korean Patent Application No. 10-2024-0117383, filed August 30, 2024, the entire contents of which are incorporated herein by reference.

[0003] A secondary battery is a device that converts external electrical energy into chemical energy, stores it, and then generates electricity when needed. They are also called rechargeable batteries, as they can be recharged multiple times. Common secondary batteries include lead-acid batteries, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), and lithium secondary batteries. Compared to disposable primary batteries, secondary batteries offer both economic and environmental benefits.

[0004] Meanwhile, with the gradual advancement of wireless communication technology, demand for lighter, thinner, and smaller portable devices and automotive components is increasing, leading to a growing demand for secondary batteries as the energy source for these devices. In particular, with the commercialization of hybrid and electric vehicles to prevent environmental pollution, research is focusing on using secondary batteries in next-generation automotive batteries to reduce manufacturing costs and weight while extending their lifespan. Among various secondary batteries, lithium secondary batteries have recently been attracting attention due to their lightweight nature, high energy density, high operating potential, and long cycle life.

[0005] In general, lithium secondary batteries are manufactured by mounting an electrode assembly consisting of a negative electrode, a positive electrode, and a separator inside a cylindrical or square metal can or a pouch-shaped case made of aluminum laminate sheet, and injecting an electrolyte into the electrode assembly.

[0006] Conventionally, liquid electrolytes, consisting of lithium salts dissolved in non-aqueous organic solvents, have been primarily used for lithium secondary batteries. However, these liquid electrolytes not only present a high risk of electrode material degradation and organic solvent volatilization, but also pose a risk of combustion or explosion due to increased ambient and battery temperature, as well as the risk of leakage. This complicates the implementation of various safe lithium secondary batteries.

[0007] Meanwhile, all-solid-state batteries using solid electrolytes have the advantage of being able to produce electrode assemblies in a safe and simple form because they exclude organic solvents.

[0008] However, to manufacture positive electrodes applicable to all-solid-state batteries, a polymer binder capable of effectively binding the positive electrode components is essential. A widely known polymer binder is nitrile rubber-based binder. However, manufacturing all-solid-state batteries using nitrile rubber-based binders suffers from reduced interfacial adhesion between the current collector and electrode, as well as reduced battery life.

[0009] Therefore, there is a need to develop a binder for the anode that can improve the mechanical properties of the electrode and increase its lifespan.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] (Patent Document 1) Republic of Korea Publication Patent No. 10-2020-0063467

[0013] (Patent Document 2) Republic of Korea Publication Patent No. 10-2020-0023308

[0014] [Non-patent literature]

[0015] (Non-patent Document 1) Journal of the Electrochemical Society, 164, A2075 (2017)

[0016] (Non-patent literature 2) ACS Energy Letters 4, 94 (2018)

[0017] (Non-patent literature 3) Ecomat, 4(4), e12193 (2022)

[0018] Accordingly, the inventors of the present invention conducted a multifaceted study to solve the above problem and, as a result, confirmed that by applying a terpolymer polymer including a repeating unit derived from ethylene, a repeating unit derived from methyl acrylate, and a repeating unit derived from glycidyl methacrylate as a binder for the positive electrode, the adhesive strength between the current collector and the electrode interface and the adhesive strength inside the electrode can be improved, thereby manufacturing a battery with improved life characteristics, thereby completing the present invention.

[0019] Accordingly, the present invention aims to provide a binder for a cathode that improves the adhesive strength between a current collector and an electrode interface and the adhesive strength inside the electrode.

[0020] In addition, the present invention aims to provide a composite cathode including the above cathode binder having improved life characteristics and an all-solid-state battery including the same.

[0021] In one aspect of the present invention, the composite positive electrode includes a positive electrode active material, a conductive material, a solid electrolyte, and a polymer binder, and the polymer binder may be a terpolymer polymer including a repeating unit derived from ethylene, a repeating unit derived from methyl acrylate, and a repeating unit derived from glycidyl methacrylate.

[0022] The polymer binder may include a terpolymer polymer including a repeating unit represented by the following chemical formula 1, a repeating unit represented by the following chemical formula 2, and a repeating unit represented by the following chemical formula 3:

[0023] [Chemical Formula 1]

[0024]

[0025] [Chemical Formula 2]

[0026]

[0027] [Chemical Formula 3]

[0028]

[0029] In the above chemical formulas 1 to 3,

[0030] p, q, and r are the mole numbers of repeating units, respectively.

[0031] p, q, and r are each independently an integer between 1 and 100.

[0032] The above polymer binder may be a polymer including a cross-repeating unit represented by the following chemical formula 4:

[0033] [Chemical Formula 4]

[0034]

[0035] In the above chemical formula 4, A is a repeating unit represented by the above chemical formula 1, B is a repeating unit represented by the above chemical formula 2, and C is a repeating unit represented by the above chemical formula 3.

[0036] In the above chemical formula 4, for 1 mole of r, p:q can be a molar ratio of 30 to 50: 1 to 5.

[0037] In the above chemical formula 4, p:q:r may be 40:4:1.

[0038] In one aspect of the present invention, a composite anode is provided in which the content of the polymer binder is 3 wt% or less based on the total weight of the composite anode.

[0039] In one aspect of the present invention, a composite cathode is provided in which the cathode active material includes a lithium transition metal composite oxide, and the transition metal includes at least one of Co, Mn, Ni, and Al.

[0040] In one aspect of the present invention, the lithium transition metal composite oxide provides a composite positive electrode including at least one compound represented by the following chemical formula 5:

[0041] [Chemical Formula 5]

[0042] Li x Ni a Co b Mn c M z O y

[0043] In the above chemical formula 5, 0.5≤x≤1.5, 0≤a≤1, 0≤b<1, 0≤c<1, 0≤z<1, 1.5 <y<5이며, a+b+c+z는 1이하이며, M은 Al 중 선택된 1종 이상을 포함한다.

[0044] In one aspect of the present invention, the solid electrolyte provides a composite positive electrode which is a sulfide-based solid electrolyte.

[0045] In one aspect of the present invention, the sulfide-based solid electrolyte provides a composite positive electrode including at least one selected from the group consisting of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2S5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, and Li2S-GeS2-ZnS.

[0046] In one aspect of the present invention, an all-solid-state battery is provided including the composite positive electrode, negative electrode, and a solid electrolyte interposed therebetween.

[0047] The present invention includes a terpolymer polymer including a repeating unit derived from ethylene, a repeating unit derived from methyl acrylate, and a repeating unit derived from glycidyl methacrylate as a polymer binder, thereby increasing the binding strength of a composite positive electrode and improving the adhesive strength between the collector-electrode interface and the adhesive strength inside the electrode.

[0048] In addition, by including the above ternary copolymer polymer, there is an effect of improving the life characteristics of the all-solid-state battery.

[0049] Figure 1 is a schematic diagram illustrating the manufacturing process of a composite anode for an all-solid-state battery.

[0050] FIG. 2 is a drawing showing an X-ray powder diffraction (XRD) pattern of a solid electrolyte and a mixture of the solid electrolyte and a binder according to one embodiment of the present invention.

[0051] FIG. 3 is a diagram showing a nano-indentation curve of a composite anode according to one embodiment and a comparative example of the present invention.

[0052] FIG. 4 is a diagram showing a SAICAS schematic diagram and measurement results of a composite anode according to one embodiment and a comparative example of the present invention.

[0053] FIG. 5 is a schematic diagram of nano scratches and a drawing showing measurement results of a composite anode according to one embodiment and a comparative example of the present invention.

[0054] FIG. 6 is a diagram showing the GITT analysis results of a composite anode according to one embodiment and a comparative example of the present invention.

[0055] FIG. 7 is a drawing showing the ionic conductivity of a composite solid electrolyte and an image of a composite solid electrolyte sheet according to one embodiment and a comparative example of the present invention.

[0056] Figure 8 is a drawing showing an initial charge / discharge curve of an all-solid-state battery according to one embodiment of the present invention.

[0057] Figure 9 is a diagram showing the discharge capacity according to the cycle of an all-solid-state battery according to one embodiment of the present invention.

[0058] Figure 10 is a drawing showing the first charge / discharge curve of an all-solid-state battery according to one embodiment and a comparative example of the present invention.

[0059] FIG. 11 is a diagram showing a CV electrochemical stability evaluation curve of a composite solid electrolyte sheet according to one embodiment of the present invention.

[0060] Figure 12 is a diagram showing discharge capacity according to cycle of an all-solid-state battery according to one embodiment and a comparative example of the present invention.

[0061] Figure 13 is a diagram showing the discharge capacity according to the current of an all-solid-state battery according to one embodiment and a comparative example of the present invention.

[0062] Figure 14 is an image showing a cross-section of a composite anode before and after a cycle according to one embodiment and a comparative example of the present invention.

[0063] Hereinafter, the present invention will be described in more detail.

[0064] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0065] The terminology used in the present invention is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In the present invention, it should be understood that the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0066]

[0067] Lithium secondary batteries have been used in small applications such as mobile phones and laptops, but their applications are recently expanding to medium- to large-sized applications such as electric vehicles and energy storage devices. Unlike small-sized batteries, these batteries face harsher operating environments and require more batteries, necessitating both superior performance and stability.

[0068] Most lithium secondary batteries currently commercialized use liquid electrolytes that are lithium salts dissolved in organic solvents. The organic solvents contained in the liquid electrolytes are easily volatile and flammable, posing a potential risk of fire and explosion. There is also a risk of leakage, which reduces long-term reliability.

[0069] Accordingly, development of all-solid-state batteries, which replace the liquid electrolytes of lithium secondary batteries with solid electrolytes, is underway. All-solid-state batteries are attracting attention as batteries that do not contain volatile organic solvents, thus eliminating the risk of explosion or fire. They are also economical, highly productive, and capable of producing high-output batteries.

[0070] To achieve high energy density in all-solid-state batteries, the production of a polymer binder capable of effectively binding the cathode components is essential. Conventionally, the polymer binder used for the cathode utilizes a widely known nitrile rubber-based binder material, but this material suffers from reduced interfacial adhesion between the current collector and electrode and reduced battery life.

[0071] Accordingly, the present invention sought to provide a binder for an anode that can improve the mechanical properties of an electrode and increase the lifespan.

[0072] Hereinafter, the composition and effects of the present invention will be described in detail.

[0073] In one embodiment of the present invention, the composite positive electrode includes a positive electrode active material, a conductive material, a solid electrolyte, and a polymer binder, wherein the polymer binder includes a tertiary copolymer polymer.

[0074] The above terpolymer may include repeating units derived from ethylene, repeating units derived from methyl acrylate, and repeating units derived from glycidyl methacrylate.

[0075] The above ternary copolymer polymer may include a repeating unit represented by the following chemical formula 1, a repeating unit represented by the following chemical formula 2, and a repeating unit represented by the following chemical formula 3:

[0076] [Chemical Formula 1]

[0077]

[0078] [Chemical Formula 2]

[0079]

[0080] [Chemical Formula 3]

[0081]

[0082] In the above chemical formulas 1 to 3,

[0083] p, q, and r are the mole numbers of repeating units, respectively.

[0084] p, q, and r are each independently an integer between 1 and 100.

[0085] The above terpolymer may be a polymer including a cross-repeating unit represented by the following chemical formula 4:

[0086] [Chemical Formula 4]

[0087]

[0088] In the above chemical formula 4, A is a repeating unit represented by the above chemical formula 1, B is a repeating unit represented by the above chemical formula 2, and C is a repeating unit represented by the above chemical formula 3.

[0089] In the above chemical formula 4, for 1 mole of r, p:q can be a molar ratio of 30 to 50: 1 to 5. For example, the molar ratio of p, q, and r can be 30:5:1, 40:5:1, 50:5:1, 30:4:1, 40:4:1, 50:4:1, 30:3:1, 40:3:1, 50:3:1, 30:2:1, 40:2:1, 50:2:1, 30:1:1, 40:1:1, 50:1:1, but is not limited to these examples.

[0090] With respect to 1 mol of the above r, as the molar ratio of p decreases based on the molar ratio of q, the flexibility imparted to the polymer binder decreases, thereby reducing the resistance to volume fluctuations of the positive electrode active material. In other words, this causes a decrease in the capacity retention rate during cycle life evaluation, and there is a problem that the ignition cycle discharge capacity also decreases.

[0091] For 1 mole of the above r, as the molar ratio of r increases based on the molar ratio of q, there is a problem that the molar ratio of q decreases relatively, thereby reducing the binding capacity. In other words, there is a problem that the binding capacity decreases, resulting in a decrease in the Martian cycle discharge capacity and also a decrease in the cycle capacity retention rate.

[0092] When the molar ratio of p is less than 30 based on the molar ratio of 1 to 5 of q for 1 mol of the above r, the flexibility imparted to the polymer binder decreases, causing a problem of brittleness during electrode manufacture. In addition, when the molar ratio of p is less than 10 based on the molar ratio of 1 to 5 of q, the molar ratio of q relatively increases, causing an increase in the polarity of the polymer itself, causing a problem of insolubility in a low-polarity solvent during electrode manufacture. The low-polarity solvent may be butyl butyrate.

[0093] For 1 mol of the above r, when the molar ratio of p exceeds 50 based on the molar ratio of 1 to 5 of q, there is a problem that the binding force imparted to the polymer binder decreases, causing detachment between the current collector and the positive electrode complex.

[0094] For 1 mole of the above r, it is preferable that p be in a molar ratio of 30 to 50 based on a molar ratio of 1 to 5 of q. More preferably, for 1 mole of the above r, p:q may be in a molar ratio of 40:4.

[0095] In the above molar ratios of p, q, and r, when the molar ratio of q exceeds 5 based on the molar ratio of 30 to 50 of p, the molar ratio of q relatively increases, so that the polarity of the polymer itself increases, causing a problem of not dissolving in a low-polarity solvent during electrode manufacture. The low-polarity solvent may be butyl butyrate.

[0096]

[0097] In the above p, q and r, when r is 0, the flexibility and bonding strength imparted to the polymer binder decrease, making it difficult to manufacture a battery.

[0098] In one embodiment of the present invention, the composite positive electrode includes a polymer binder content of 3 wt% or less based on the total weight of the composite positive electrode. When the content of the polymer binder exceeds 3 wt% based on the total weight of the composite positive electrode, the binding capacity is improved, but the content of the solid electrolyte, which acts as a lithium ion migration path within the composite positive electrode, is reduced, and thus, smooth movement of lithium ions within the electrode is restricted, resulting in a problem of increased resistance. That is, when the content of the polymer binder exceeds 3 wt% based on the total weight of the composite positive electrode, there is a problem of continuous decrease in charge and discharge capacity because lithium ions cannot move smoothly within the electrode.

[0099] Specifically, the content of the polymer binder may be 3.0 wt% or less, 2.5 wt% or less, 2.0 wt% or less, or 0.5 wt% or more, 1.0 wt% or more, or 1.5 wt% or more based on the total weight of the composite anode.

[0100] In one embodiment of the present invention, the solid electrolyte may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may include a solid electrolyte containing sulfur (S) and having the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table.

[0101] The above sulfide-based solid electrolyte may include at least one selected from the group consisting of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2S5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, and Li2S-GeS2-ZnS, but is not limited to these examples.

[0102] In the present invention, the average particle diameter of the sulfide-based solid electrolyte can be adjusted to a range suitable for an all-solid-state battery. In a specific embodiment of the present invention, the solid electrolyte may have an average particle diameter of 0.1 μm to 10 μm. More specifically, the solid electrolyte may have an average particle diameter of 0.1 ㎛ or more, 0.5 ㎛ or more, 1.0 ㎛ or more, 1.5 ㎛ or more, 2.0 ㎛ or more, 2.5 ㎛ or more, 3.0 ㎛ or more, 3.5 ㎛ or more, 4.0 ㎛ or more, 4.5 ㎛ or more, 5.0 ㎛ or more, or 10 ㎛ or less, 9.5 ㎛ or less, 9.0 ㎛ or less, 8.5 ㎛ or less, 8.0 ㎛ or less, 7.5 ㎛ or less, 7.0 ㎛ or less, 6.5 ㎛ or less, 6.0 ㎛ or less, 5.5 ㎛ or less, 5.0 ㎛ or less, but is not limited to these examples.

[0103] Also in one embodiment of the present invention, the selected solid electrolyte is 1x10 -5 S / cm, preferably 1x10 -3 It has an ionic conductivity of S / cm or more.

[0104] In one embodiment of the present invention, the solid electrolyte layer can be manufactured, for example, by the following method.

[0105] First, a solid electrolyte is prepared. The solid electrolyte can be obtained commercially or prepared using the method described below. The solid electrolyte can be prepared using the method described below.

[0106] First, LiCl, Li2S, and P2S5 are mixed in stoichiometric amounts and milled using a planetary ball mill or the like to obtain a homogeneous mixture. The mixture is heat-treated at a high temperature for a predetermined period of time to obtain the desired Li6PS5Cl solid electrolyte. The heat-treatment can be performed at approximately 550°C and the heat-treatment time can be approximately 8 hours.

[0107] Next, the above solid electrolyte material is added and dispersed in a predetermined organic solvent to prepare a slurry, which is then applied to a molding plate or the like, dried, and formed into a sheet shape. If necessary, the sheet-shaped resultant can be pressurized to obtain a solid electrolyte layer.

[0108] In one embodiment of the present invention, the positive electrode active material is lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound of formula Li. 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33, e.g., LiMn2O4), LiMnO3, LiMn2O3, LiMnO2, lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV2O4, V2O5, Cu2V2O7, chemical formula LiNi 1-x M x O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and 0 <x<1)으로 표현되는 Ni 사이트형 리튬 니켈 산화물, 예를 들어, LiNi 1-z (Co, Mn, Al) z O2(0 <z<1); 화학식 LiMn 2-x M x O4 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 1, e.g. LiMn 1.5 Ni 0.5 O4) or a lithium manganese composite oxide represented by Li2Mn3MO8 (wherein, M = Fe, Co, Ni, Cu or Zn); LiMn2O4 in which a portion of Li in the chemical formula is substituted with an alkaline earth metal ion; a disulfide compound; Fe2(MoO4)3, lithium iron phosphate (LiFePO4) may include one or a mixture of two or more thereof. In one embodiment of the present invention, the lithium iron phosphate may have all or at least a portion of the surface of the active material particles coated with a carbon material to improve conductivity.

[0109] Preferably, the positive electrode active material is lithium nickel cobalt manganese oxide (e.g., Li(Ni,Co,Mn)O2, LiNi 1-z (Co,Mn,Al) z O2(0 <z<1)), 리튬 철 인산(Lithium Iron Phosphate)(예를 들어, LiFePO4 / C), 리튬 니켈 망간 스피넬(Lithium Nickel Manganese Spinel)(예를 들어, LiNi 0.5 Mn 1.5 O4), lithium nickel cobalt aluminum oxide (e.g., Li(Ni,Co,Al)O2), lithium manganese oxide (e.g., LiMn2O4), and lithium cobalt oxide (e.g., LiCoO2).

[0110] In the present invention, most preferably, the positive electrode active material includes a lithium transition metal composite oxide, and the transition metal may include at least one of Co, Mn, Ni, and Al.

[0111] In one embodiment of the present invention, the lithium transition metal composite oxide may include at least one compound represented by the following chemical formula 5.

[0112] <Chemical Formula 5>

[0113] Li x Ni a Co b Mn c M z O y

[0114] In the above chemical formula 5, 0.5≤x≤1.5, 0≤a≤1, 0≤b<1, 0≤c<1, 0≤z<1, 1.5 <y<5이며, a+b+c+z는 1 이하이며, M은 Al 중 선택된 1종 이상을 포함한다.

[0115] In a specific embodiment of the present invention, the positive electrode conductive material may be, for example, one selected from the group consisting of graphite, carbon black, carbon fibers or metal fibers, metal powders, conductive whiskers, conductive metal oxides, activated carbon, and polyphenylene derivatives, or a mixture of two or more conductive materials thereof. More specifically, the positive electrode conductive material may be one selected from the group consisting of natural graphite, artificial graphite, super-p, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, Denka black, aluminum powder, nickel powder, zinc oxide, potassium titanate, and titanium oxide, or a mixture of two or more conductive materials thereof.

[0116] The above-mentioned current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, stainless steel, copper, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used.

[0117] In one embodiment of the present invention, the solid electrolyte included in the positive electrode may include at least one selected from a polymer-based solid electrolyte, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte. In one embodiment of the present invention, the positive electrode active material may preferably include the sulfide-based solid electrolyte described for the solid electrolyte.

[0118] In one embodiment of the present invention, it is preferable that the positive electrode active material is included in an amount of 70 wt% or more relative to 100 wt% of the positive electrode active material layer. In addition, it is preferable that the solid electrolyte is included in the positive electrode in an amount of 10 wt% to 30 wt% relative to 100 wt% of the positive electrode active material layer.

[0119] Meanwhile, in a specific embodiment of the present invention, the positive electrode has a capacity of 5 mAh / cm 2 Above, 6 mAh / cm 2 or more than 10 mAh / cm 2 The above loading amount (per electrode area) can be achieved.

[0120] In the battery according to the present invention, even when such a high-loading positive electrode is applied, the battery can be operated at an electrochemically stable level.

[0121] Meanwhile, in a specific embodiment of the present invention, the positive electrode active material layer can be obtained by casting a slurry prepared by adding a positive electrode active material, a conductive material, a binder resin, and a solid electrolyte to an appropriate solvent.

[0122] The present invention will be further described below through examples. However, the following examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention. These examples are provided to more fully explain the present invention to those of ordinary skill in the art.

[0123]

[0124] Manufacturing Example 1: Manufacturing of EMG terpolymer polymer binder

[0125] According to the present invention, a polymer binder is prepared by producing a terpolymer (hereinafter referred to as “EMG terpolymer”) comprising a repeating unit derived from ethylene, a repeating unit derived from ethyl methacrylate, and a repeating unit derived from glycidyl methacrylate.

[0126] To initiate the nickel enolate catalyst-based reaction during the polymerization process, a 0.02 wt% nickel enolate catalyst solution was prepared by pre-mixing a trifluoromethane ligand precursor (SigmaAldrich) and Ni(COD)2 (COD = 1,5-cyclooctadiene) (SigmaAldrich) in 30 ml of toluene solvent for 15 minutes. Afterwards, glycidyl methacrylate (SigmaAldrich) (C) was dissolved in toluene solvent at a molar ratio of 1.6 M, ethyl methacrylate (TCI) (B) and glycidyl methacrylate (SigmaAldrich) (C) were dissolved in toluene solvent at a molar ratio of 4:1, and the nickel enolate catalyst solution prepared above and a co-catalyst of methylaluminoxane (SigmaAldrich) were added. Afterwards, the ethylene group (A) in the polymer was injected with glycidyl methacrylate (SigmaAldrich) (C) at a molar ratio of 40:1 by controlling the flow rate of ethylene gas, thereby preparing an EMG terpolymer. The reaction was terminated by adding methanol to the reactor.

[0127] The above polymerization reaction was maintained at 55°C through a temperature-controlling water flow between the inner jacket and the outer jacket of a Buchi autoclave (Buchiglas) to increase the yield through sufficient activation of the catalyst, and the internal pressure was maintained at approximately 4 atm while ethylene gas was supplied.

[0128]

[0129] Manufacturing Example 2

[0130] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 30: 4: 1.

[0131]

[0132] Manufacturing Example 3

[0133] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of the ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 50: 4: 1.

[0134]

[0135] Comparative Example 1

[0136] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of the ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 10: 4: 1.

[0137]

[0138] Comparative Example 2

[0139] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 60: 4: 1.

[0140]

[0141] Comparative Example 3

[0142] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 5: 4: 1.

[0143]

[0144] Comparative Example 4

[0145] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 40: 4: 0.

[0146]

[0147] Comparative Example 5

[0148] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 40:20:1.

[0149]

[0150] Comparative Example 6

[0151] An EMG terpolymer was prepared in the same manner as in Manufacturing Example 1, except that the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) was 20:40:1.

[0152]

[0153] Experimental Example 1: Comparison of electrode fabrication including EMG terpolymer binder according to repeat unit molar ratio

[0154] In the EMG terpolymer according to Manufacturing Example 1, in the case of the copolymer according to Comparative Example 1 in which the molar ratio of ethylene groups (A) was significantly reduced, the flexibility was reduced and a brittle phenomenon was observed during electrode manufacture. When the manufactured electrode was physically folded, unlike the electrode having sufficient flexibility, the positive electrode composite fragmented and cracked. Therefore, when the copolymer according to Comparative Example 1 was included, there was difficulty in manufacturing an all-solid-state battery electrode.

[0155] In addition, in the case of the copolymer according to Comparative Example 2, in which the molar ratio of ethylene groups (A) was significantly increased in the EMG terpolymer according to Manufacturing Example 1, the binding force as a polymer binder was reduced, resulting in detachment between the current collector and the positive electrode composite. Therefore, in the case of including the copolymer according to Comparative Example 2, there was difficulty in manufacturing an all-solid-state battery electrode due to the reduced binding force.

[0156] In addition, in the case of the copolymers according to Comparative Examples 3, 5, and 6, the polarity of the polymer itself increased due to the increase in the molar ratio of ethyl methacrylate (B) to ethylene group (A), so that it was not dissolved in butyl butyrate, a low-polarity solvent for electrode production, making it difficult to produce an all-solid-state battery electrode.

[0157] In addition, in the case of the copolymer according to Comparative Example 4, since it did not contain glycidyl methacrylate (C), it was confirmed that the bonding strength was reduced due to the composite peeling off at the edge of the electrode when the electrode was stamped for battery production. In addition, it was confirmed that the flexibility was also reduced due to the composite surface being formed somewhat rough. Therefore, in the case of including the copolymer according to Comparative Example 4, there was difficulty in manufacturing an all-solid-state battery electrode.

[0158] Therefore, in manufacturing a composite cathode including an EMG terpolymer and an all-solid-state battery including the same, it was confirmed that it is most appropriate to manufacture a copolymer in which the molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) is 30 to 50: 1 to 5: 1.

[0159]

[0160] Experimental Example 2: Comparison of electrode fabrication including EMG terpolymer binder according to the molar ratio of repeating units.

[0161] In the EMG terpolymers according to Manufacturing Examples 1 to 3, the discharge capacity and capacity retention rate of the battery according to the molar ratio of ethylene groups (A) were evaluated. The results of the discharge capacity and capacity retention rate are shown in Table 1 below.

[0162]

[0163] Mars Cycle Discharge Capacity (mAh / g) Cycle Characteristics (0.2 C) Initial Capacity (mAh / g) Capacity Retention Rate (%) Manufacturing Example 1199.1158.995.6 Manufacturing Example 2197.1156.090.3 Manufacturing Example 3194.8146.291.4

[0164]

[0165] As shown in Table 1 above, in the case of the copolymer according to Manufacturing Example 2 in which the molar ratio of ethylene groups (A) was reduced in the EMG terpolymer according to Manufacturing Example 1, the flexibility as a polymer binder was reduced, so that the resistance to volume fluctuations of the active material was reduced, and this caused a decrease in the capacity retention rate during cycle life evaluation, and it was confirmed that the combustion cycle discharge capacity was also reduced compared to Manufacturing Example 1.

[0166] In addition, in the case of the copolymer according to Manufacturing Example 3 in which the molar ratio of ethylene groups (A) was increased in the EMG terpolymer according to Manufacturing Example 1, the cohesive force was reduced and the binding ability was reduced due to the relatively reduced molar ratio of ethyl methacrylate (B) to ethylene groups (A), so that a clear decrease in the chemical cycle discharge capacity was also observed, and it was confirmed that the cycle capacity retention rate was also reduced compared to Manufacturing Example 1.

[0167] Therefore, in the manufacture of a composite cathode including an EMG terpolymer and an all-solid-state battery including the same, it was confirmed that a composite cathode including a copolymer having a molar ratio of ethylene group (A), ethyl methacrylate (B), and glycidyl methacrylate (C) of 40:4:1 improved the mechanical properties of the electrode and had a high lifespan.

[0168]

[0169] Example 1: Composite cathode with EMG terpolymer binder and all-solid-state battery using the same

[0170] LiNi 0.9 Co 0.05 Mn 0.05 O2, Li6PS5Cl (LPSCl) powder (manufactured by Posco JK solid solution), Super C (manufactured by Timcal), and the EMG terpolymer manufactured in Manufacturing Example 1 were mixed in a butyl butyrate solvent to prepare a slurry. The slurry was mixed for 15 minutes with a Thinky Mixer (manufactured by Thinky), and cast on an aluminum current collector with a doctor blade to prepare a composite cathode. The mass ratio of the cathode active material, solid electrolyte, conductive material, and binder in the manufactured composite cathode was 75:21.5:1.5:2. The manufactured composite cathode had an active material content of 15 mg / cm2 per area. 2 It was manufactured by loading.

[0171] 100 mg of Li6PS5Cl powder was placed in a PET mold and pressurized at room temperature under a pressure of 300 MPa to produce Li6PS5Cl pellets. The composite cathode thus prepared was then placed therein and pressurized under a pressure of 430 MPa. Li-In foil (Lithium (Honjo), Indium (Nilaco)) was placed on the opposite side of the Li6PS5Cl pellets and then fastened under a pressure of 60 MPa to produce an all-solid-state battery.

[0172]

[0173] Example 2

[0174] An all-solid-state battery was manufactured in the same manner as in Example 1, except that the mass ratio of the positive electrode active material, solid electrolyte, conductive material, and binder in the composite positive electrode was 75:22.5:1.5:1.

[0175]

[0176] Example 3

[0177] An all-solid-state battery was manufactured in the same manner as in Example 1, except that the mass ratio of the positive electrode active material, solid electrolyte, conductive material, and binder in the composite positive electrode was 75:20.5:1.5:3.

[0178]

[0179] Comparative Example 7

[0180] An all-solid-state battery was manufactured in the same manner as in Example 1, except that the mass ratio of the positive electrode active material, solid electrolyte, conductive material, and binder in the composite positive electrode was 75:19.5:1.5:4.

[0181]

[0182] Experimental Example 3: Comparison of electrode fabrication according to polymer binder content

[0183] In the all-solid-state batteries according to Examples 1, 3, and Comparative Example 7, the discharge capacity and capacity retention rate of the batteries according to the binder content in the composite positive electrode were evaluated. The results of the discharge capacity and capacity retention rate are shown in Table 2 below.

[0184]

[0185] Mars Cycle Discharge Capacity (mAh / g) Cycle Characteristics (0.2 C) Initial Capacity (mAh / g) Capacity Retention Rate (%) Example 1 199.1 158.9 95.6 Example 3 194.6 153.5 90.1 Comparative Example 7 187.7 135.6 85.3

[0186]

[0187] As shown in Table 2 above, as the polymer binder content within the electrode increases, the content of the solid electrolyte, which acts as a lithium ion migration path, decreases, thereby restricting the smooth movement of lithium within the electrode and increasing resistance. Therefore, although the binding capacity improves depending on the binder content, the movement of lithium ions within the composite positive electrode is hindered, preventing the smooth movement of lithium ions within the electrode, and a continuous decrease in the charge and discharge capacity of the battery was confirmed.

[0188] Therefore, it was confirmed that the batteries according to Examples 1 and 3 having a polymer binder content of 3 wt% or less had better cycle discharge capacity and capacity retention rate than the batteries according to Comparative Example 7 having a polymer binder content of more than 3 wt%.

[0189]

[0190] Comparative Example 8: Composite anode with nitrile-butadiene rubber applied and all-solid-state battery using the same

[0191] LiNi 0.9 Co 0.05 Mn 0.05 O2, Li6PS5Cl (LPSCl) powder, Super C, and nitrile-butadiene rubber (Kumho Petro Chemical) were mixed in a butyl butyrate solvent to prepare a slurry. The slurry was mixed for 15 minutes using a Thinky Mixer (Thinky), and cast on an aluminum current collector using a doctor blade to prepare a composite cathode. The mass ratio of the cathode active material, solid electrolyte, conductive material, and binder in the manufactured composite cathode was 75:21.5:1.5:2. The manufactured composite cathode had an active material content of 15 mg / cm2 per area. 2 It was manufactured by loading.

[0192] 100 mg of Li6PS5Cl powder was placed in a PET mold and pressurized at room temperature under a pressure of 300 MPa to produce Li6PS5Cl pellets. The composite cathode thus prepared was then placed therein and pressurized under a pressure of 430 MPa. Li-In foil was placed on the opposite side of the Li6PS5Cl pellets and then fastened under a pressure of 60 MPa to produce an all-solid-state battery.

[0193]

[0194] Experimental Example 4: Evaluation of Chemical Stability of Composite Anodes with EMG Terpolymer Binder

[0195] In order to evaluate the chemical stability of the composite anode manufactured in Example 1, XRD evaluation was performed, and the results are shown in Fig. 2.

[0196] The presence of side reactions in the butyl butyrate solvent and EMG terpolymer binder used in the composite anode manufacturing process was determined as follows:

[0197] First, a solution was prepared by reacting LPSCl solid electrolyte with butyl butyrate solvent for 24 hours, and a solution was prepared by mixing LPSCl solid electrolyte with EMG terpolymer binder solution and reacting for 24 hours. After drying the above solutions in a vacuum oven, XRD evaluation was performed on the remaining residual materials, and as shown in Fig. 2, it was confirmed that the structural stability of the LPSCl solid electrolyte was well maintained in all compositions.

[0198]

[0199] Experimental Example 5: Mechanical Properties Evaluation of Composite Anodes with EMG Terpolymer Binder (Nano Indenter) - Hardness Measurement

[0200] The hardness of the composite anode according to Example 1 and Comparative Example 8 was measured. The evaluation was performed using nano-indentation equipment, and the results are shown in Figure 3 below.

[0201] Specifically, the hardness was measured by indenting an electrode specimen with an indenter (Vickers Indenter, tip width 0.5 ㎛) using a nanoindenter (NHT3, manufactured by Anton Paar). Specifically, the indenter was loaded onto the electrode specimen at a speed of 0.1 mN / s for 10 seconds, applying a maximum force of 1 mN, creeping for 10 seconds, and then the indenter was unloaded at a speed of 0.1 mN / s for 10 seconds, and the resulting indentation hardness was measured.

[0202] As a result of the above hardness measurement, the composite anode of Example 1 showed a smaller penetrated depth than the composite anode of Comparative Example 1. Table 3 below shows the results showing the hardness of the composite anode.

[0203]

[0204] Example 1 Comparative Example 8 Hardness (GPa) 0.0025 0.0012

[0205]

[0206] As shown in Table 3 above, it was confirmed that the composite anode of Example 1 including the EMG terpolymer had greater hardness than the composite anode of Comparative Example 8.

[0207]

[0208] Experimental Example 6: Mechanical Properties Evaluation of Composite Anodes with EMG Terpolymer Binder (SAICAS) - Interfacial Adhesion Measurement

[0209] The interfacial adhesion of the composite anodes according to Example 1 and Comparative Example 8 was measured. The evaluation was performed using SAICAS (Surface and Interfacial Cutting Analysis System) equipment, and the results are shown in Figure 4 below.

[0210] Specifically, the interfacial adhesion was measured using SAICAS equipment (SAICAS EN-EX (Daipla Wintes, Japan). The horizontal force was measured through the force applied to the blade while cutting the anode in the depth direction with a diamond micro blade. The horizontal force is a value that measures the force applied horizontally to the micro blade to maintain the constant cutting speed.

[0211] The internal adhesive force between the composite anode materials in the composite anodes according to Example 1 and Comparative Example 8 was measured through a constant velocity mode, and the interfacial adhesive force between the composite anode and the current collector was measured through a constant load mode (Rake angle: 20°, Clearance angle: 10°). Figures 4(a) and 4(b) are drawings showing the internal adhesive force between the composite anode materials, and Figures 4(c) and 4(d) are drawings showing the interfacial adhesive force between the composite anode and the current collector.

[0212] The higher the horizontal force required to maintain the cutting speed input as the set value, the harder the material is, making it difficult to cut, i.e., the better the bonding strength. Accordingly, it was found that the composite anode according to Example 1 had superior adhesive strength at the interface and internally compared to the composite anode according to Comparative Example 8.

[0213]

[0214] Experimental Example 7: Mechanical Properties Evaluation of Composite Anodes with EMG Terpolymer Binder (Nano Scratch) - Hardness Measurement

[0215] The hardness of the composite anode according to Example 1 and Comparative Example 8 was measured. The evaluation was performed using a nano scratch device, and the results are shown in Figure 5 below.

[0216] Specifically, the hardness was measured using a nano scratch device (Anton Paar). A blade, which had penetrated into the electrode through a pre-processing procedure, was moved at a constant velocity horizontally and under the same load vertically, a distance of approximately 50 μm within the electrode, and the penetration depth of the blade within the anode was measured (Scanning velocity = 10 μm / s, Scratch load = 200 mN). Figure 5(a) is a schematic diagram of the nano scratch.

[0217] When the same load value was set, the harder the material, the smaller the blade penetration depth. It was confirmed that the depth was shallower in the composite anode according to Example 1 compared to the composite anode according to Comparative Example 8. Fig. 5(b) is a drawing showing the measurement results of the penetration depth. Through this, it was confirmed that the composite anode according to Example 1 had better hardness than the composite anode according to Comparative Example 8.

[0218]

[0219] Experimental Example 8: Measurement of Surface Activation of Composite Positive Electrode Active Material with EMG Terpolymer Binder

[0220] The surface activation of the positive electrode active materials distributed in the composite positive electrodes according to Example 1 and Comparative Example 8 was compared. The results of the GITT (Galvanostatic Intermittent Titration Technique) analysis are shown in Figure 6 below.

[0221] The all-solid-state batteries according to Example 1 and Comparative Example 8 were prepared by charging and discharging at a current rate of 0.05 C, and then a state charged at a current rate of 0.05 C was prepared. Thereafter, a current of 0.2 C was applied for 1 minute, followed by a 2-hour rest, to compare the surface activation of the positive electrode active material.

[0222] The all-solid-state battery according to Example 1 was observed to have lower polarization than the all-solid-state battery according to Comparative Example 8, and the final discharge capacity was 181.0 mAh / g for Comparative Example 8 and 189.8 mAh / g for Example 1, confirming that the surface activation of the positive electrode active material was superior for Example 1.

[0223]

[0224] Experimental Example 9: Measurement of the ionic conductivity of a composite solid electrolyte with an EMG terpolymer binder.

[0225] The ionic conductivity of the composite solid electrolyte applied to the all-solid-state battery according to Example 1 and Comparative Example 8 was measured. A solid electrolyte sheet was prepared by mixing the LPSCl solid electrolyte and a binder at a weight ratio of 95:5. Figure 7(b) is a drawing showing the prepared solid electrolyte sheet.

[0226] The ionic conductivity of LPSCl alone was 2.41 mS / cm, and in the case of the composition with the binder applied, it had similar values ​​of 0.44 mS / cm when including nitrile rubber and 0.45 mS / cm when including EMG terpolymer. Fig. 7(a) is a diagram showing the ionic conductivity of the composite solid electrolyte applied to the all-solid-state battery according to Comparative Example 8 and Example 1. Through this, it was confirmed that the EMG terpolymer binder showed similar characteristics to the nitrile rubber binder in terms of ionic conductivity.

[0227]

[0228] Experimental Example 10: Cycle life characteristics evaluation of all-solid-state batteries based on composite cathodes with different amounts of EMG terpolymer binder.

[0229] Prior to evaluating the all-solid-state batteries manufactured in Examples 1 to 3, the optimal binder composition was explored by applying different contents of the EMG terpolymer.

[0230] Figure 8 is a charge-discharge curve of a formation cycle obtained by charging and discharging at a current rate of 0.05 C. Table 4 below shows the discharge capacities based on the positive electrode active material of an all-solid-state battery containing 1, 2, and 3 wt % of an EMG ternary copolymer binder.

[0231]

[0232] Example 1 Example 2 Example 3 Discharge capacity (mAh / g) 199.1 196.8 194.6

[0233]

[0234] After completing two Mars cycles, the discharge capacity according to the cycle obtained by charging and discharging at a current rate of 0.2 C is shown in Fig. 9. Table 5 below shows the initial discharge capacity and the capacity retention rate at 20 cycles at a current rate of 0.2 C.

[0235]

[0236] Example 1 Example 2 Example 3 Discharge capacity (mAh / g) 158.9 155.3 153.5 Capacity retention rate (%) 95.6 92.6 90.1

[0237]

[0238] As shown in Table 5 above, the all-solid-state battery of Example 1, which applied 2 wt% of the MG terpolymer binder, exhibited the best cycle characteristics. Therefore, it can be seen that the optimal content of the EMG terpolymer binder is 2 wt%.

[0239]

[0240] Experimental Example 11: Evaluation of Cycle Life and High-Rate Characteristics of Composite Anode-Based All-Solid-State Batteries with EMG Terpolymer Binders

[0241] Figure 10 is a charge-discharge curve of a formation cycle obtained by charging and discharging the all-solid-state batteries manufactured in Comparative Example 8 and Example 1 at a current rate of 0.05 C. The all-solid-state batteries of Comparative Example 8 and Example 1 showed discharge capacities based on the positive electrode active material as shown in Table 6 below.

[0242]

[0243] Example 1 Comparative Example 8 Discharge capacity (mAh / g) 199.1 196.0

[0244]

[0245] As shown in Table 6 above, it can be seen that the all-solid-state battery of Example 1 has a higher initial capacity than the all-solid-state battery of Comparative Example 8. Table 7 below shows the efficiency (discharge capacity / charge capacity x 100%) in the initial Mars cycle.

[0246]

[0247] Example 1 Comparative Example 8 Efficiency (%) 87.483.1

[0248]

[0249] To verify the above efficiency, cyclic voltammetry (CV) analysis was performed, and the results are shown in Fig. 11. The nitrile rubber and EMG terpolymer electrolyte sheet used in the analysis is a solid electrolyte sheet with a 5 wt% binder weight ratio applied in Experimental Example 9. The voltage range is 1.0 to 3.7 V (vs. Li-In), and the evaluation was performed at a scan rate of 0.5 mV / s. The reason for the difference in efficiency in the initial formation cycle of the battery life evaluation can be explained by the fact that more side reactions were observed during the initial voltage increase process in Comparative Example 8. After completing two formation cycles, the discharge capacity according to the cycle obtained by charging and discharging at a current rate of 0.2 C is shown in Fig. 12. The initial discharge capacity and capacity retention rate of the all-solid-state batteries of Comparative Example 8 and Example 1 at a current rate of 0.2 C are shown in Table 8 below.

[0250]

[0251] Example 1 Comparative Example 8 Discharge capacity (mAh / g) 158.9 150.7 Capacity retention rate (%) 88.5 81.3

[0252]

[0253] As shown in Table 8 above, it can be seen that the all-solid-state battery of Example 1 using the EMG ternary copolymer binder exhibits better cycle characteristics. The discharge capacity according to the change in current rate of the all-solid-state batteries manufactured in Comparative Example 8 and Example 1 is shown in Figure 13. The discharge capacity at a current rate of 1.0 C is as shown in Table 9 below.

[0254]

[0255] Example 1 Comparative Example 8 Discharge capacity (mAh / g) 87.468.4

[0256]

[0257] As shown in Table 9 above, the all-solid-state battery of Example 1 exhibits better high-rate characteristics than that of Comparative Example 8.

[0258]

[0259] Experimental Example 12: Cross-sectional image analysis of a composite anode with an EMG terpolymer binder applied.

[0260] In order to compare the cross-sections of composite anodes for all-solid-state batteries before and after cycling according to the type of applied polymer binder, scanning electron microscope (FE-SEM, Hitachi) analysis of the cross-sections of composite anodes was performed, and the results are shown in Fig. 14.

[0261] Fig. 14(a) is an image showing a cross-section before cycling of a composite anode for an all-solid-state battery manufactured from Comparative Example 8, and Fig. 14(b) is an image showing a cross-section before cycling of a composite anode for an all-solid-state battery manufactured from Example 1. In the cross-section before cycling, it is observed that there are no cracks in the positive electrode active material for both the one applying the nitrile rubber binder of Comparative Example 8 and the one applying the EMG terpolymer binder of Example 1.

[0262] Fig. 14(c) is an image showing a cross-section of a composite anode for an all-solid-state battery manufactured from Comparative Example 8 after 100 cycles, and Fig. 14(d) is an image showing a cross-section of a composite anode for an all-solid-state battery manufactured from Example 1 after 100 cycles. After 100 cycles, numerous cracks in the active material were found in Comparative Example 8, whereas in Example 1, the shape of the active material was generally well preserved, and it was confirmed that the interface between the active material and the solid electrolyte was stably maintained.

Claims

1. Contains a positive electrode active material, a conductive material, a solid electrolyte and a polymer binder, A composite anode, wherein the polymer binder is a terpolymer polymer containing repeating units derived from ethylene, repeating units derived from methyl acrylate, and repeating units derived from glycidyl methacrylate.

2. In paragraph 1, The above polymer binder is a composite anode, which is a terpolymer polymer including a repeating unit represented by the following chemical formula 1, a repeating unit represented by the following chemical formula 2, and a repeating unit represented by the following chemical formula 3: [Chemical Formula 1] [Chemical Formula 2] [Chemical Formula 3] In the above chemical formulas 1 to 3, p, q, and r are the mole numbers of repeating units, respectively. p, q, and r are each independently an integer between 1 and 100.

3. In paragraph 2, The above polymer binder is a composite anode comprising a polymer including a cross-repeating unit represented by the following chemical formula 4: [Chemical Formula 4] In the above chemical formula 4, A is a repeating unit represented by the above chemical formula 1, B is a repeating unit represented by the above chemical formula 2, and C is a repeating unit represented by the above chemical formula 3.

4. In paragraph 3, A composite anode in which, in the above chemical formula 4, p:q is a molar ratio of 30 to 50: 1 to 5 for 1 mole of r.

5. In paragraph 3, A composite anode, where p:q:r is 40:4:

1.

6. In paragraph 1, A composite anode, wherein the content of the polymer binder is 3 wt% or less based on the total weight of the composite anode.

7. In paragraph 1, The above positive electrode active material includes a lithium transition metal composite oxide, A composite anode, wherein the above transition metal comprises at least one of Co, Mn, Ni, and Al.

8. In paragraph 7, The above lithium transition metal composite oxide is a composite positive electrode comprising at least one compound represented by the following chemical formula 5: [Chemical Formula 5] Li x Ni a Co b Mr c M z O y In the above chemical formula 5, 0.5≤x≤1.5, 0≤a≤1, 0≤b<1, 0≤c<1, 0≤z<1, 1.5 <y<5이며, a+b+c+z는 1이하이며, M은 Al 중 선택된 1종 이상을 포함한다.

9. In paragraph 1, A composite anode, wherein the above solid electrolyte is a sulfide-based solid electrolyte.

10. In paragraph 9, A composite cathode, wherein the above sulfide-based solid electrolyte comprises at least one selected from the group consisting of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2S5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, and Li2S-GeS2-ZnS.

11. A composite anode according to any one of claims 1 to 10; cathode; and An all-solid-state battery comprising a solid electrolyte interposed between them.

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