Anode for all-solid-state battery, and all-solid-state battery comprising same

Abstract

The present invention relates to an anode for an all-solid-state battery, and an all-solid-state battery comprising same, the anode comprising: an anode current collector; an amorphous carbon layer disposed at one surface of the anode current collector; and a porous sheet within the amorphous carbon layer.

Description

Anode for an all-solid-state battery and an all-solid-state battery comprising the same

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0077975, filed June 19, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to a negative electrode for an all-solid-state battery and an all-solid-state battery including the same.

[0003]

[0004] Lithium secondary batteries, which are reusable and have high energy density, are attracting attention as a new energy source that not only can drastically reduce the use of fossil fuels, but is also environmentally friendly because they do not produce byproducts from energy use.

[0005] The aforementioned lithium secondary batteries are attracting attention not only as energy sources for wearable and portable devices, but also for high-power, high-energy-density devices such as electric vehicles. Accordingly, research into lithium secondary batteries with high operating voltage and energy density is becoming increasingly active.

[0006] Lithium secondary batteries are charged and discharged through the process of lithium ions moving between the positive and negative electrodes. Some of the lithium ions that move to the negative electrode attach to the surface of the negative electrode to form lithium nuclei, and these lithium nuclei can grow to become lithium dendrites, which are branch-shaped crystals.

[0007] If lithium dendrites formed and grown on the surface of the negative electrode come into contact with the positive electrode, they can cause a short circuit in the lithium secondary battery, which can shorten the lifespan of the lithium secondary battery and also cause problems in ensuring stable performance.

[0008] Moreover, in all-solid-state batteries with high energy density, there is a problem that short circuits frequently occur due to the weak strength of the solid electrolyte membrane placed between the positive and negative electrodes.

[0009] To increase the energy density of all-solid-state batteries, the use of lithium as an anode active material has been proposed. Methods for using lithium as an anode active material include using lithium or a lithium alloy as the anode active material, or using lithium precipitated at the interface between the anode current collector and the solid electrolyte during charging without forming a layer of the anode active material on the anode current collector.

[0010] When lithium is used as an anode active material, lithium is deposited on the anode side during charging, and if an anode active material layer is not formed, lithium is deposited on the anode current collector. The lithium deposited on the anode side in this way can grow into lithium dendrites through the gaps in the solid electrolyte when the all-solid-state battery is repeatedly charged and discharged. The lithium dendrites can cause short circuits or capacity reduction in the battery. In addition, there may be a problem that the anode is stressed due to volume expansion of the anode during the charge and discharge process, which may cause cracks.

[0011] Therefore, there is a high need for technology that can prevent the growth of lithium dendrites and solve the problem of cracking.

[0012]

[0013] [Previous literature]

[0014] [Patent Document]

[0015] Republic of Korea Publication Patent No. 10-2018-0091678

[0016]

[0017] In order to solve the above problem, the inventors of the present invention conducted a multifaceted study and confirmed that by forming an amorphous carbon layer including a porous sheet inside on one side of a negative electrode current collector, lithium dendrites can be suppressed and volume expansion of the negative electrode that occurs during charging and discharging of an all-solid-state battery can be minimized, thereby completing the present invention.

[0018] Accordingly, the present invention aims to provide an anode for an all-solid-state battery that can suppress the formation of lithium dendrites and minimize volume expansion of the anode, thereby preventing phenomena such as cracks and breakage occurring in the anode.

[0019] In addition, the present invention aims to provide an all-solid-state battery capable of improving the life characteristics of the all-solid-state battery by including the above-mentioned all-solid-state battery negative electrode.

[0020]

[0021] To achieve the above purpose,

[0022] The present invention comprises: a negative electrode current collector;

[0023] An amorphous carbon layer located on one surface of the negative electrode collector; and

[0024] A negative electrode for an all-solid-state battery is provided, comprising a porous sheet inside the amorphous carbon layer.

[0025] In addition, the present invention includes an anode; a cathode; and a solid electrolyte layer positioned between the anode and the cathode,

[0026] The above negative electrode is a negative electrode for an all-solid-state battery of the present invention,

[0027] An all-solid-state battery is provided, wherein the solid electrolyte layer faces the amorphous carbon layer of the negative electrode.

[0028]

[0029] The anode for an all-solid-state battery of the present invention can suppress the formation of lithium dendrites and minimize volume expansion of the anode, thereby preventing phenomena such as cracks and breakage occurring in the anode.

[0030] Therefore, an all-solid-state battery including this may have improved life-cycle characteristics.

[0031]

[0032] Figure 1 illustrates a negative electrode for an all-solid-state battery of the present invention.

[0033] Figure 2 illustrates an all-solid-state battery of the present invention.

[0034] Figure 3 illustrates a state in which the all-solid-state battery of the present invention is charged.

[0035] Figure 4 is a graph measuring the life characteristics of the all-solid-state battery of Experimental Example 1.

[0036]

[0037] Hereinafter, the present invention will be described in more detail.

[0038]

[0039] 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.

[0040] 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.

[0041]

[0042] Cathode for all-solid-state batteries

[0043] The present invention relates to a negative electrode for an all-solid-state battery, and the negative electrode for an all-solid-state battery of the present invention comprises:

[0044] negative current collector;

[0045] An amorphous carbon layer located on one surface of the negative electrode collector; and

[0046] A porous sheet may be included within the amorphous carbon layer.

[0047]

[0048] The anode for an all-solid-state battery of the present invention is of a type that does not separately include an anode active material layer on the anode current collector. That is, the anode of the present invention does not include an anode active material and may be an anode-free type.

[0049]

[0050] Fig. 1 illustrates an anode (100) for an all-solid-state battery of the present invention. Referring to this, the anode (100) for an all-solid-state battery of the present invention has a form in which an anode current collector (110) and an amorphous carbon layer (120) are laminated on one surface of the anode current collector (110), and a porous sheet (130) may be positioned inside the amorphous carbon layer (120). The porous sheet (130) may be embedded in the amorphous carbon layer (120).

[0051]

[0052] The negative electrode current collector (110) is not particularly limited as long as it has excellent conductivity and is electrochemically stable in the voltage range of a lithium secondary battery. For example, the negative electrode current collector (110) may be any one metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof. The stainless steel may be surface-treated with carbon, nickel, titanium, or silver. As the alloy, an aluminum-cadmium alloy may be preferably used. In addition, calcined carbon, a non-conductive polymer surface-treated with a conductive material, or a conductive polymer may be used.

[0053]

[0054] The above amorphous carbon layer (120) may be formed by dispersing amorphous carbon in a solvent to produce a slurry and coating it on one surface of the negative electrode current collector (110).

[0055] The above amorphous carbon may include carbon black such as acetylene black, furnace black, Ketjen black, or graphene; or the like.

[0056] The above amorphous carbon layer (120) may perform the role of ion transport. More specifically, the amorphous carbon layer (120) may transport lithium ions moving to the negative electrode (100) toward the negative electrode current collector (110) without impeding the movement of lithium ions from the positive electrode (200) to the negative electrode (100) or from the negative electrode (100) back to the positive electrode (200).

[0057] Therefore, when the above-described all-solid-state battery negative electrode (100) is laminated with a solid electrolyte layer (300) and a positive electrode (200) to manufacture a battery and then charging is performed, lithium ions that have moved to the negative electrode (100) through the amorphous carbon layer (120) can be deposited at the interface between the negative electrode current collector (110) and the amorphous carbon layer (120) to form a lithium layer (400), and the formation of lithium dendrites can be suppressed. Therefore, even if the all-solid-state battery negative electrode (100) of the present invention does not include a negative electrode active material, lithium is deposited at the interface between the negative electrode current collector (110) and the amorphous carbon layer (120) through charging, and thus the all-solid-state battery can function and suppress the formation of lithium dendrites, thereby improving the life characteristics of the all-solid-state battery.

[0058]

[0059] Since lithium ions move through amorphous carbon, the volume of the amorphous carbon may expand during charging and discharging of the all-solid-state battery. This expansion may cause the negative electrode (100) to be stressed, causing cracks and other problems, which may lower stability and deteriorate the lifespan characteristics of the all-solid-state battery.

[0060] Therefore, in the present invention, by including a support inside the amorphous carbon layer (120), the volume expansion of the amorphous carbon that occurs during charging and discharging of the all-solid-state battery is buffered, thereby facilitating the movement of lithium ions and increasing the mechanical strength to improve the life characteristics of the all-solid-state battery.

[0061] That is, the present invention may include a porous sheet (130) inside the amorphous carbon layer (120), and the porous sheet (130) may serve as a support that supports the amorphous carbon.

[0062] Since the above porous sheet (130) is located inside the amorphous carbon layer (120), i.e., is in an embedded form, the porous sheet (130) may contain amorphous carbon in the pores and surface thereof.

[0063] The above porous sheet (130) may be in the form of a non-woven fabric and may be made of polyethylene, polypropylene, or a mixture thereof.

[0064] In addition, the porosity of the porous sheet (130) may be 70 to 95%. Within the porosity range of the porous sheet (130), the porous sheet (130) can serve as a support that buffers the volume expansion of amorphous carbon that occurs during charging and discharging of an all-solid-state battery, thereby solving problems such as breakage or cracking of the anode (100) for an all-solid-state battery.

[0065] The pores of the above porous sheet (130) are structured to be interconnected with each other, so that they penetrate from one side of the sheet to the other side, allowing a fluid substance to pass through.

[0066] The volume ratio of the porous sheet (130) and the amorphous carbon layer (120) may be 5:95 to 30:70, preferably 10:90 to 20:80. Within the above volume ratio range, the porous sheet (130) can serve as a support that buffers the volume expansion of the amorphous carbon that occurs during charging and discharging of the all-solid-state battery. In addition, the amorphous carbon can facilitate the movement of lithium ions, thereby suppressing the growth of lithium dendrites and enabling lithium to be stably deposited at the interface between the negative electrode current collector (110) and the amorphous carbon layer (120).

[0067]

[0068] The above-mentioned all-solid-state battery negative electrode (100) may be manufactured by positioning a porous sheet (130) on a negative electrode collector (110) and then applying and drying a slurry containing amorphous carbon.

[0069] Alternatively, it may be manufactured by manufacturing a porous sheet (130) on a negative electrode collector (110) and then applying and drying a slurry containing amorphous carbon.

[0070] In order to secure a bonding force between the negative electrode current collector (110) and the porous sheet (130), a solution containing a binder may be cast on the negative electrode current collector (110) and then the porous sheet (130) may be positioned or manufactured. The type of the binder is not particularly limited as long as it is used in the art.

[0071] In addition, since a slurry containing amorphous carbon is applied onto the porous sheet (130), the porous sheet (130) may be positioned within the amorphous carbon layer (120), and the amorphous carbon may be positioned on the surface and pores of the porous sheet (130). In addition, the amorphous carbon may be positioned in some of the pores or may be positioned in a form that blocks all of the pores.

[0072] Preferably, a slurry containing amorphous carbon may be applied and dried on the porous sheet (130) so that the porous sheet (130) is positioned inside the amorphous carbon layer (120). In the present invention, 'inside' may mean that the porous sheet (130) is embedded in the amorphous carbon layer (120). The porous sheet (130) has a structure in which a plurality of pores are interconnected to each other, and thus has a form in which the porous sheet penetrates from one side of the sheet to the other side, so that a slurry containing amorphous carbon can be inserted into the pores, or amorphous carbon can be inserted into the pores through rolling. Therefore, amorphous carbon can be fully filled in the penetrated pores, so that amorphous carbon can also be positioned on the surface of the negative electrode current collector (110).

[0073]

[0074] The above amorphous carbon layer (120) may additionally include a binder to secure bonding strength between amorphous carbons and to secure bonding strength between the negative electrode current collector (110) and the amorphous carbon layer (120).

[0075] The binder may include, but is not limited to, one or more selected from the group consisting of, for example, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), styrene butylene rubber, fluororubber, and copolymers thereof.

[0076] The above amorphous carbon layer (120) may contain a binder in an amount of 1 to 10 wt%, preferably 3 to 7 wt%, based on the total weight of the amorphous carbon layer (120). In this case, the amorphous carbon layer (120) may mean that it does not contain a porous sheet (130) therein, i.e., that it is composed only of amorphous carbon.

[0077]

[0078] All-solid-state batteries

[0079] In addition, the present invention relates to an all-solid-state battery comprising: a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode.

[0080] The above negative electrode is the negative electrode for the all-solid-state battery of the present invention described above,

[0081] The above solid electrolyte layer may face the amorphous carbon layer of the negative electrode.

[0082]

[0083] Figure 2 illustrates an all-solid-state battery of the present invention. Referring to this, the all-solid-state battery of the present invention has a structure in which a negative electrode (100), a solid electrolyte layer (300), and a positive electrode (200) are sequentially laminated, and the amorphous carbon layer (120) of the negative electrode (100) and the solid electrolyte layer (300) may face each other.

[0084] Figure 3 illustrates a state in which the all-solid-state battery of the present invention is charged. Referring to this, a lithium layer (400) may be formed at the interface between the negative electrode current collector (110) and the amorphous carbon layer (120). This may be because lithium ions released from the positive electrode (200) move through the solid electrolyte layer (300) and the amorphous carbon layer (120) of the negative electrode (100) and are deposited at the interface between the negative electrode current collector (110) and the amorphous carbon layer (120) to form the lithium layer (400).

[0085] Accordingly, the all-solid-state battery of the present invention may form a lithium layer (400) at the interface between the negative electrode current collector (110) and the amorphous carbon layer (120) through charging. The lithium layer (400) may include both a structure in which lithium metal is formed as a layer and a porous structure (for example, a structure in which lithium metal is aggregated in the form of particles) in which lithium metal is not formed as a layer. Although the present invention is described based on the form of the lithium layer (400), it is clear that this description does not exclude a structure in which lithium metal is not formed as a layer.

[0086]

[0087] The above positive electrode (200) may include a positive electrode current collector and a positive electrode active material layer applied to one or both sides of the positive electrode current collector.

[0088] The above positive electrode collector may be the same as the above-described negative electrode collector (110).

[0089] The above positive electrode active material layer may include a positive electrode active material and optionally a solid electrolyte, a conductive material, and a binder.

[0090] The above positive electrode active material may be a lithium source for forming a lithium layer (400).

[0091] The above positive electrode active material may vary depending on the type of all-solid-state battery. For example, the positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4(0≤x≤0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-x M xNi-site lithium nickel oxide represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga; 0.01≤x≤0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxides expressed as O2 (M = Co, Ni, Fe, Cr, Zn or Ta; 0.01≤x≤0.1) or Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn); LiNi x Mn 2-x Lithium manganese composite oxide with spinel structure represented by O4; LiCoPO4; LiFePO4; Elemental sulfur (S8); Li2S n (n=1), organosulfur compounds or carbon-sulfur polymers (C2S x ) n : It may include sulfur series compounds such as x=2.5 ~ 50, n=2), but is not limited to these.

[0092] The above conductive material is a material that electrically connects the electrolyte and the positive electrode active material and serves as a path for electrons to move from the current collector to the positive electrode active material. Any material that does not cause chemical changes in a lithium secondary battery and has porosity and conductivity can be used without restriction.

[0093] For example, the conductive material may be a porous carbon-based material, such as carbon black, graphite, graphene, activated carbon, carbon fiber, etc.; metallic fibers such as metal mesh; metallic powders such as copper, silver, nickel, aluminum, etc.; or organic conductive materials such as polyphenylene derivatives. The conductive materials may be used alone or in combination.

[0094] Current commercially available products include acetylene black series (such as those from Chevron Chemical Company or Gulf Oil Company), Ketjen Black EC series (from Armak Company), Vulcan XC-72 (from Cabot Company), and Super P (from MMM). Examples include acetylene black, carbon black, and graphite.

[0095] In addition, the positive electrode (200) may additionally include a binder, and the binder increases the bonding strength between the components constituting the positive electrode (200) and between them and the current collector, and any binder known in the industry may be used.

[0096] For example, the binder may be a fluororesin binder including polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butidiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; a polyester binder; and a silane binder. One, two or more mixtures or copolymers selected from the group consisting of may be used.

[0097] The above solid electrolyte may include at least one selected from the group consisting of a sulfide-based solid electrolyte, a polymer-based solid electrolyte, and an oxide-based solid electrolyte, and preferably may include a sulfide-based solid electrolyte.

[0098] The above sulfide-based solid electrolyte contains sulfur (S) and has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and may include Li-PS-based glass or Li-PS-based glass ceramic.

[0099] Specifically, the 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, and preferably may include at least one selected from the group consisting of Li6PS5Cl, Li6PS5Br, and Li6PS5I. The above Li6PS5Cl, Li6PS5Br, and Li6PS5I may be argyrodite type solid electrolytes. In addition, the sulfide-based solid electrolyte may be in a form doped with trace elements, for example, Li6PS5Cl may be additionally doped with bromine (Br).

[0100] The above polymer-based solid electrolyte is a polymer electrolyte material formed by adding a polymer resin to a composite of a lithium salt and a polymer resin, that is, a solvated lithium salt, and is about 1x10 -7 S / cm or more, preferably about 1x10 -5 It can exhibit ionic conductivity of S / cm or more.

[0101] Non-limiting examples of the polymer resin include polyether polymers, polycarbonate polymers, acrylate polymers, polysiloxane polymers, phosphazene polymers, polyethylene derivatives, alkylene oxide derivatives such as polyethylene oxide, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, etc., and may include one or more of these. In addition, the polymer electrolyte may include, as a polymer resin, a branched copolymer in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane (PDMS) and / or phosphazene is copolymerized as a comonomer in a polyethylene oxide (PEO) main chain, a comb-like polymer, and a cross-linked polymer resin, and may include one or more of these.

[0102] In the above polymer solid electrolyte, the above-mentioned lithium salt is an ionizable lithium salt, Li + X - It can be expressed as . There is no particular limitation on the anion of these lithium salts, but F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH- , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , (CF3CF2SO2)2N - Examples include:

[0103] The above oxide-based solid electrolyte may contain oxygen (O) and have the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. For example, an LLTO-based compound, Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP compounds, LATP compounds, Li1 +x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1, 0≤y≤1), LiTi x Zr 2-x (PO4)3 (wherein, 0≤x≤1, 0≤y≤1), may include at least one selected from among LISICON compounds, LIPON compounds, perovskite compounds, NASICON compounds, and LLZO compounds.

[0104]

[0105] The above solid electrolyte layer (300) includes a solid electrolyte having lithium ion conductivity, and may include the solid electrolyte described above. In addition, it may additionally include a binder, and the binder also follows the above description.

[0106]

[0107] The manufacture of the above all-solid-state battery is not particularly limited in the present invention, and a known method can be used.

[0108] For example, a solid electrolyte membrane is placed between an anode (200) and a cathode (100), and then the solid electrolyte membrane is compressed or rolled to assemble a cell. The assembled cell is then installed in an outer packaging material and sealed by heating and compression, etc. The outer packaging material may be a laminate pack made of aluminum, stainless steel, or a metal container having a cylindrical or square shape.

[0109] For example, the positive electrode (200) is manufactured through a slurry coating process in which a slurry composition including a positive electrode active material, a conductive material, a solid electrolyte, a solvent, and a binder is manufactured, coated, and then dried.

[0110] Methods for coating the above-described positive electrode slurry on a current collector include a method of distributing the positive electrode slurry on the current collector and then uniformly dispersing it using a doctor blade or the like, die casting, comma coating, screen printing, etc. In addition, the positive electrode slurry may be formed on a separate substrate and then bonded to the current collector by a pressing or lamination method. At this time, the final coating thickness can be controlled by adjusting the concentration of the slurry solution or the number of coatings.

[0111] The drying process is a process of removing the solvent and moisture within the slurry to dry the slurry coated on the metal collector. This process may vary depending on the solvent used. For example, it is performed in a vacuum oven at 50 to 200°C. Examples of drying methods include drying using warm air, hot air, or low-humidity air, vacuum drying, and drying using irradiation with (far) infrared rays or electron beams. The drying time is not particularly limited, but is typically performed within the range of 30 seconds to 24 hours.

[0112] After the above drying process, a cooling process may be further included, and the cooling process may be slow cooling to room temperature so that the recrystallized structure of the binder is well formed.

[0113] The shape of the above-mentioned all-solid-state battery is not particularly limited, and can be made into various shapes such as cylindrical, laminated, and coin-shaped.

[0114]

[0115] Hereinafter, preferred examples are presented to help understand the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present invention, and it is also natural that such changes and modifications fall within the scope of the appended patent claims.

[0116]

[0117] <Manufacturing of all-solid-state batteries>

[0118] Example 1.

[0119] A positive electrode was manufactured by mixing a positive electrode active material (NCM 811), a conductive agent (carbon fiber), a solid electrolyte (Li6PS5Cl), and a binder (polytetrafluoroethylene) in a weight ratio of 84:0.2:14.8:1, applying the mixture to a positive electrode current collector, drying it, and then rolling it.

[0120] A solid electrolyte (Li6PS5Cl) and a binder (styrene-butadiene-styrene copolymer) were mixed in a weight ratio of 98:2, and the mixture was added to anisole to prepare a slurry. The slurry was applied and dried on a release film (polyethylene terephthalate) using a bar coater, and the release film was then removed to prepare a solid electrolyte layer.

[0121] A 10 μm thick SUS negative current collector was prepared. A solution containing a binder (PVDF) was cast on the negative current collector, and then a porous sheet (PP / PE nonwoven fabric, 89% porosity) was positioned. A slurry mixed with acetylene black and binder (PVDF) at a weight ratio of 93.5:6.5 was coated and dried to produce an amorphous carbon layer. The negative electrode has an amorphous carbon layer positioned on the negative current collector, and includes a porous sheet within the amorphous carbon layer.

[0122] The above positive electrode, solid electrolyte layer, and negative electrode were sequentially laminated, and the solid electrolyte layer and the amorphous carbon layer of the negative electrode were laminated so that they faced each other, thereby manufacturing an all-solid-state battery.

[0123]

[0124] Comparative Example 1.

[0125] A 10 μm thick SUS negative electrode collector was prepared. A slurry containing acetylene black and a binder (PVDF) in a weight ratio of 93.5:6.5 was coated and dried to produce an amorphous carbon layer. The negative electrode has an amorphous carbon layer positioned on the negative electrode collector, and does not contain a porous sheet within the amorphous carbon layer.

[0126] The positive electrode and solid electrolyte layer were manufactured in the same manner as in Example 1 to manufacture an all-solid-state battery.

[0127]

[0128] Experimental Example 1. Measurement of the life characteristics of an all-solid-state battery.

[0129] The life characteristics of the all-solid-state batteries of Example 1 and Comparative Example 1 were measured.

[0130] The life characteristics were measured by charging the all-solid-state battery at 0.33C in CCCV mode at a temperature of 60℃ until it reached 4.25V, then cutting off at 0.1C, and discharging it at 0.33C to 3.0V in CC mode, and measuring the capacity retention rate when 50 charge and discharge cycles were performed.

[0131] The results are shown in Figure 4.

[0132] The all-solid-state battery of Example 1 of the present invention exhibited a capacity retention rate of 92.6%.

[0133] However, the all-solid-state battery of Comparative Example 1 had a short circuit in the 16th cycle and showed very poor life characteristics.

[0134] That is, in the case of an anode for an all-solid-state battery, it can be seen that including a porous sheet inside an amorphous carbon layer not only suppresses the formation of lithium dendrites, but also cushions the volume expansion of amorphous carbon that occurs when the all-solid-state battery is charged and discharged, thereby facilitating the movement of lithium ions and solving the problem of anode damage, thereby providing an all-solid-state battery with excellent life characteristics.

[0135]

[0136] [Explanation of symbols]

[0137] 100: Negative

[0138] 110: Negative current collector

[0139] 120: Amorphous carbon layer

[0140] 130: Porous sheet

[0141] 200: Bipolar

[0142] 300: Solid electrolyte layer

[0143] 400: Lithium layer

Claims

1. Negative current collector; An amorphous carbon layer located on one surface of the negative electrode collector; and An anode for an all-solid-state battery, comprising a porous sheet inside the amorphous carbon layer.

2. In paragraph 1, An anode for an all-solid-state battery, comprising amorphous carbon in the pores and surface of the porous sheet.

3. In paragraph 1, The above porous sheet is a non-woven fabric, a negative electrode for an all-solid-state battery.

4. In paragraph 3, The above nonwoven fabric is a negative electrode for an all-solid-state battery made of polyethylene, polypropylene or a mixture thereof.

5. In paragraph 1, An anode for an all-solid-state battery, wherein the porosity of the above porous sheet is 70 to 95%.

6. In paragraph 1, An anode for an all-solid-state battery, wherein the volume ratio of the porous sheet and the amorphous carbon layer is 5:95 to 30:

70.

7. In paragraph 1, An anode for an all-solid-state battery, wherein the amorphous carbon layer further comprises a binder.

8. In paragraph 7, An anode for an all-solid-state battery, wherein the amorphous carbon layer comprises a binder in an amount of 1 to 10 wt% based on the total weight of the amorphous carbon layer.

9. In paragraph 1, An anode for an all-solid-state battery, in which a layer of anode active material is not formed on the anode current collector.

10. Including a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode, The above negative electrode is a negative electrode for an all-solid-state battery according to claim 1, An all-solid-state battery, wherein the solid electrolyte layer faces the amorphous carbon layer of the negative electrode.

11. In paragraph 10, When charging the above solid-state battery, An all-solid-state battery in which lithium deposition occurs at the interface between the negative electrode current collector and the amorphous carbon layer.

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