Electrode for all-solid-state battery and all-solid-state battery including same

Abstract

The invention relates to an electrode for an all-solid-state battery and an all-solid-state battery including the same. An electrode for an all-solid-state battery is provided, characterized by a current collector, a first coating layer formed on the current collector, and a second coating layer selectively applied to a partial region of the first coating layer. This design optimizes the pressure profile during battery assembly and operation, reduces surface degradation, and prevents dendritic crystal formation. Further, a conductive material layer is formed on a partial region of the second coating layer to enhance conductivity between the second coating layer and the solid electrolyte. The invention also includes a method for preparing an electrode and assembling an all-solid-state battery, which includes placing a pressing member on a region of the electrode where a second coating is absent. The disclosed electrode structure significantly improves the performance, durability, and safety of all-solid-state batteries.

Description

[0001] Citations of relevant applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2024-0063475, filed with the Korean Intellectual Property Office on May 14, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to an electrode for all-solid-state batteries, characterized by a novel structure designed to enhance the overall performance of the all-solid-state battery. This improvement is achieved by minimizing electrode surface degradation and dendrite formation during the rolling pressing process. Specifically, a thinner coating is selectively applied only to regions of pressure concentration during the process, while a conductive material layer is formed on a portion of the second coating to enhance conductivity between the second coating and the solid electrolyte. This disclosure also includes methods for fabricating the electrode and assembling the all-solid-state battery, and the strategic placement of pressing members in areas where the second coating of the electrode is absent to further optimize battery performance and durability. Background Technology

[0004] Recently, various batteries have been researched and investigated to overcome the limitations of lithium-ion batteries in terms of capacity, stability, power output, and size (whether increasing or decreasing). Among these, all-solid-state batteries refer to batteries with a solid electrolyte instead of the liquid electrolyte used in conventional lithium-ion batteries. According to all-solid-state batteries, since no flammable solvents are used inside the battery, the risk of fire or explosion due to the decomposition reactions of conventional electrolytes is eliminated, thus significantly improving stability.

[0005] All-solid-state batteries are fabricated by forming a stacked structure comprising a positive electrode, a negative electrode, and a solid electrolyte between the positive and negative electrodes, followed by roll-pressing the stacked structure. Specifically, all-solid-state batteries require maximizing contact at the interfaces between the positive and solid electrolytes, and between the solid electrolyte and the negative electrode. Therefore, all-solid-state batteries are driven while maintaining relatively high pressures applied to the stacked structure.

[0006] One of the most widely used methods for applying high pressure during operation is to press the battery stack structure using pressing members such as pressing clamps. However, due to the structural characteristics of pressing members such as pressing clamps, the pressure may be applied unevenly, resulting in higher pressure being applied to certain areas. Furthermore, when higher pressure is applied to certain areas, current density concentration occurs in those areas. Therefore, the electrode surface may deteriorate and dendrites may form.

[0007] Therefore, there is a need for an all-solid-state battery with a novel structure and its fabrication method, which can minimize pressure deviation even when using existing pressing components to press the stacked structure, thereby preventing surface property degradation and improving the durability and performance of the all-solid-state battery. Summary of the Invention

[0008] This disclosure has been made to address the aforementioned problems in the prior art while maintaining the advantages achieved by the prior art.

[0009] One aspect of this disclosure provides an electrode for an all-solid-state battery and a method for preparing the same, as well as an all-solid-state battery including the electrode and a method for preparing the same.

[0010] Another aspect of this disclosure provides an electrode for an all-solid-state battery and a method for preparing the same, as well as an all-solid-state battery including the electrode and a method for preparing the same, wherein the electrode is capable of unifying surface pressure during battery assembly and driving by selectively excluding a second coating only in areas where pressure is to be applied after assembling the all-solid-state battery, thereby improving the performance and durability of the all-solid-state battery.

[0011] The technical problems to be solved by this disclosure are not limited to those described above, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

[0012] To address the aforementioned issues, this disclosure provides an electrode for an all-solid-state battery, an all-solid-state battery including the electrode, a method for preparing the electrode for an all-solid-state battery, and a method for preparing an all-solid-state battery.

[0013] In some embodiments, the electrode for an all-solid-state battery includes a current collector, a first coating formed on the current collector, and a second coating formed on a portion of the first coating. The electrode may have a region where the first coating is surrounded by the second coating. The ratio of the thickness of the second coating to the thickness of the first coating may be in the range of about 1% to 5%. Furthermore, the ratio of the area having the second coating to the area having the first coating may be in the range of about 60% to 90%. The loading level of the electrode active material in the second coating may be at least about 2% of the loading level in the first coating. Both the first and second coatings may include the electrode active material, a binder, and a solid electrolyte. A pressing member may be placed on an area of ​​the electrode where the second coating is not present.

[0014] In some embodiments, the all-solid-state battery includes electrodes and a solid electrolyte as described above. The battery may further include a conductive material layer formed on a portion of the second coating, wherein the conductive material layer is configured to enhance conductivity between the second coating and the solid electrolyte. The conductive material layer may include materials such as carbon black, conductive graphite, ethylene black, or graphene and may selectively be formed only in regions of the second coating that are in direct contact with the solid electrolyte layer. The solid electrolyte layer is located between the electrodes and the opposing electrodes, and pressure can be applied to the electrodes using a pressing member, wherein the pressing member is placed on an area where the second coating is not present.

[0015] In some embodiments, a method for fabricating electrodes for an all-solid-state battery includes: forming a first coating on a current collector, placing a mask on the first coating, forming a second coating, and then removing the mask. The mask may comprise a material such as polyethylene, polytetrafluoroethylene, or polyethylene naphthalate, and may have a thickness in the range of about 5 μm to 50 μm. The method may also include coating and drying a first coating slurry comprising electrode active material, conductive material, binder, and solid electrolyte on the current collector, followed by coating and drying a second coating slurry having similar components.

[0016] In some embodiments, the method for fabricating an all-solid-state battery sequentially includes: stacking the described electrodes, a solid electrolyte layer, and a counter electrode, followed by rolling the stacked structure using a pressing member. The pressing member may be placed on a region where the second coating of the electrodes is absent. The electrodes for the all-solid-state battery may serve as either positive or negative electrodes, and the counter electrode may be the corresponding negative or positive electrode.

[0017] More specifically, (1) this disclosure provides an electrode for an all-solid-state battery, the electrode including a current collector, a first coating formed on the current collector, and a second coating formed on a portion of the first coating.

[0018] (2) This disclosure provides an electrode for an all-solid-state battery according to (1), wherein a region of a region having a first coating but not having a second coating is surrounded by a region having a second coating.

[0019] (3) This disclosure provides an electrode for an all-solid-state battery according to (1) or (2), wherein the ratio of the thickness of the second coating to the thickness of the first coating is in the range of 1% to 5%.

[0020] (4) This disclosure provides an electrode for an all-solid-state battery according to any one of (1) to (3), wherein the ratio of the area of ​​the region having the second coating to the area of ​​the region having the first coating is in the range of 60% to 90%.

[0021] (5) This disclosure provides an electrode for an all-solid-state battery according to any one of (1) to (4), wherein the ratio of the loading level of the electrode active material of the second coating to the loading level of the electrode active material of the first coating is at least 2%.

[0022] (6) This disclosure provides an electrode for an all-solid-state battery according to any one of (1) to (5), wherein the first coating comprises an electrode active material, a binder and a solid electrolyte.

[0023] (7) This disclosure provides an electrode for an all-solid-state battery according to any one of (1) to (6), wherein the second coating comprises an electrode active material, a binder and a solid electrolyte.

[0024] (8) This disclosure provides an electrode and a solid electrolyte layer for an all-solid-state battery according to any one of (1) to (7).

[0025] (9) This disclosure provides a method for preparing an electrode for an all-solid-state battery, wherein the method forms a first coating on a current collector (S1), places a mask on the first coating and forms a second coating (S2), and removes the mask (S3).

[0026] (10) This disclosure provides a method for preparing electrodes for all-solid-state batteries, wherein the mask comprises at least one material selected from the group consisting of polyethylene, polytetrafluoroethylene and polyethylene naphthalate.

[0027] (11) This disclosure provides a method for preparing electrodes for all-solid-state batteries according to (9) or (10), wherein the mask has a thickness in the range of 5 μm to 50 μm.

[0028] (12) This disclosure provides a method for preparing an electrode for an all-solid-state battery according to (9) to (11), wherein S1 includes coating and drying a first coating slurry comprising an electrode active material, a conductive material, a binder and a solid electrolyte on a current collector.

[0029] (13) This disclosure provides a method for preparing an electrode for an all-solid-state battery according to any one of (9) to (12), wherein S2 includes coating and drying a second coating slurry comprising an electrode active material, a conductive material, a binder and a solid electrolyte on a first coating.

[0030] (14) This disclosure provides a method for preparing an all-solid-state battery, the method comprising sequentially stacking an electrode, a solid electrolyte layer and a counter electrode for an all-solid-state battery according to any one of (1) to (7), and using a pressing member to roll the stacked structure, wherein the pressing member is placed on a region of the electrode for the all-solid-state battery that does not have a second coating.

[0031] (15) This disclosure provides a method for preparing an all-solid-state battery according to (14), wherein the electrode for the all-solid-state battery is a positive electrode and the opposite electrode is a negative electrode.

[0032] (16) This disclosure provides a method for preparing an all-solid-state battery according to (14), wherein the electrode for the all-solid-state battery is a negative electrode and the opposite electrode is a positive electrode.

[0033] As discussed, the method and system appropriately include the use of a controller or processor. Attached Figure Description

[0034] The above and other objects, features, and advantages of this disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0035] Figure 1 This is a schematic diagram showing the structure of an electrode for an all-solid-state battery prepared according to an embodiment of the present disclosure. Detailed Implementation

[0036] In order to understand this disclosure, it will be described in more detail below.

[0037] In this context, the terms and words used in this specification and claims should not be limited to their common dictionary meanings, but rather are intended to be interpreted in a way that allows the inventors to appropriately define the concepts of the terms in order to best interpret this disclosure, and to be relevant to the technical scope of this disclosure.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. These terms are intended only to distinguish one component from another, and these terms do not limit the nature, order, or sequence of the constituent components. It should also be understood that when the terms “comprising” and / or “including” are used in this specification, they specify the presence of the stated feature, integral, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Throughout the specification, unless explicitly stated otherwise, the word “comprising” and variations such as “including” or “containing” will be understood to imply the inclusion of the stated element, but do not exclude any other element. Furthermore, the terms “unit,” “device,” “piece,” and “module” described in the specification mean a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0039] Although the exemplary embodiments are described as using multiple units to perform the example process, it should be understood that the example process may also be performed by one or more modules. Furthermore, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store modules, and the processor is specifically configured to execute said modules to perform one or more processes further described below.

[0040] Furthermore, the control logic of this disclosure may be embodied in a non-volatile computer-readable medium containing executable program instructions that can be executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROMs, magnetic tape, floppy disks, flash drives, smart cards, and optical data storage devices. The computer-readable medium may also be distributed across a network-coupled computer system, enabling it to be stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0041] Unless otherwise specified or obvious from the context, as used herein, the term “about” should be understood as being within the normal tolerance range in the field, such as within 2 standard deviations of the mean. “About” can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless the context otherwise clarifies, all numerical values ​​provided herein are modified by the term “about”.

[0042] Electrodes for all-solid-state batteries

[0043] This disclosure provides an electrode for an all-solid-state battery, the electrode including a current collector, a first coating formed on the current collector, and a second coating formed on a portion of the first coating.

[0044] All-solid-state batteries (which include a positive electrode, a negative electrode, and a solid electrolyte between the positive and negative electrodes) are driven by pressing the stacked structure to maximize contact at the interlayer interfaces. Therefore, all-solid-state batteries can maintain excellent performance for a specific period of time or longer only when the performance of the electrodes used in the all-solid-state battery is maintained while pressing them down.

[0045] Conventional all-solid-state batteries use pressing components, such as clamps, to apply pressure to the positive and negative electrodes to maintain the aforementioned pressed state. However, such pressing components only apply pressure to the area in contact with the pressing component. Therefore, there is a limitation to applying pressure uniformly over the entire area of ​​the positive / negative electrodes.

[0046] To this end, this disclosure provides an electrode for all-solid-state batteries that employs existing commercially available pressing components, while forming a thinner coating only in areas where stronger pressure is applied by the pressing components and a thicker coating in areas where weaker pressure is applied, thereby eliminating pressure differences caused by thickness variations between coatings.

[0047] The components constituting the electrodes of the all-solid-state battery according to this disclosure will be described in more detail below.

[0048] Current collector

[0049] The current collector acts as a base to provide conductivity to the electrode while supporting the active material layer (coating) of the electrode. The current collector may include materials with specific levels of conductivity and durability.

[0050] More specifically, depending on whether the electrode is positive or negative, the current collector can be made of different materials. For example, the current collector may include copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or the above materials surface-treated with carbon, nickel, titanium, or silver, and / or aluminum-cadmium alloys. The current collector may be in the form of a film, sheet, foil, mesh, porous body, foam, or nonwoven fabric to uniformly form a layer of electrode active material on the surface of the current collector.

[0051] The current collector can have a thickness ranging from 8 μm to 25 μm, preferably from 10 μm to 20 μm. When the thickness of the current collector is within the above range, the electrode can have more uniform and superior durability and performance.

[0052] First coating and second coating

[0053] According to this disclosure, the first coating and the second coating serve as electrode active material layers. The first coating is formed on the aforementioned current collector, and the second coating is formed on the first coating.

[0054] In the electrode for an all-solid-state battery according to the present disclosure, since the second coating is formed only in a portion of the first coating, the first coating is formed in a portion of the electrode, and the stacked structure of the first and second coatings is formed in the remaining area of ​​the electrode.

[0055] This coating structure design allows for uniform pressure maintenance across the entire electrode area by forming a thinner coating only in areas where higher pressure is applied. The area of ​​the second coating can vary depending on the electrode area to which pressure is applied by the pressing member (applying pressure to the electrode of the all-solid-state battery according to this disclosure). For example, when the pressing member applies pressure to the central region of the electrode, the second coating can be formed in the remaining areas of the electrode other than the central region. In this case, the areas of the first coating that do not have the second coating can be surrounded by the areas that do have the second coating.

[0056] The first and second coatings can be distinguished according to the stacking order. The ratio of the thickness of the second coating to the thickness of the first coating can be in the range of 1% to 5%, preferably in the range of 2% to 3%. Furthermore, the thickness of the first coating can be in the range of 25 μm to 100 μm, preferably 28 μm to 98 μm, and more preferably 29 μm to 95 μm. Additionally, the thickness of the second coating can be 0.1 μm to 5 μm, preferably 0.5 μm to 3 μm.

[0057] When the thicknesses of the first and second coatings meet the above conditions, the problem of uneven pressure application by the pressing member can be minimized, and the contact at the interface between the solid electrolyte layer and the electrode active material layer can be maximized. When the second coating is much thicker than the first coating, the height difference between the area with the second coating and the area without the second coating is too large, and the electrode may break during pressing.

[0058] The ratio of the area with the second coating to the area with the first coating can be in the range of 60% to 90%, preferably 70% to 80%. Although the area with the second coating varies depending on the structural shape of the pressing member, when the ratio of the area with the second coating meets the above conditions, the surface pressure under pressing conditions can be more uniform.

[0059] In the electrode for an all-solid-state battery according to this disclosure, the ratio of the loading level of the electrode active material in the second coating to the loading level of the electrode active material in the first coating can be 2% or less, preferably 1% or less. This is also related to the thickness ratio between the first and second coatings mentioned above. When the loading level of the electrode active material in the second coating is too high as that in the first coating, the durability of the electrode can be considerably degraded.

[0060] Meanwhile, each of the first coating and the second coating may include an electrode active material, a conductive material, a binder, and a solid electrolyte. To minimize the resistance of the interface between the first coating and the second coating, the first coating and the second coating may include substantially the same components. More specifically, the first coating and the second coating may include the electrode active material, the conductive material, the binder, and the solid electrolyte provided in the same type and the same content.

[0061] When the first coating and the second coating include a positive electrode active material, the positive electrode active material may be an oxide active material or a sulfide active material.

[0062] The oxide active material may be a rock salt type active material such as LiCoO2, LiMnO2, LiNiO2, LiVO2, Li 1+x Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, a spinel type active material such as LiMn2O4, Li(Ni 0.5 Mn 1.5 )O4, an inverse spinel type active material such as LiNiVO4 or LiCoVO4, an olivine type active material such as LiFePO4, LiMnPO4, LiCoPO4 or LiNPO4, a silicon-containing active material such as Li2FeSiO4, Li2MnSiO4, a rock salt type active material such as LiNi 0.8 Co (0.2-x) Al x O2(0 < x < 0.2) (obtained by replacing a part of the transition metal with a heterogeneous metal), a spinel type active material such as Li 1+x Mn 2-x-y MyO4 (M is at least one of Al, Mg, Co, Fe, Ni, and Zn; 0 < x + y < 2) (obtained by replacing a part of the transition metal with a heterogeneous metal), or lithium titanate such as Li4Ti5O 12 . The sulfide active material may be copper Chevrel, iron sulfide, cobalt sulfide or nickel sulfide.

[0063] Meanwhile, when the first coating and the second coating include a negative electrode active material, the negative electrode active material may be a carbon active material or a metal active material.

[0064] The carbon active material may be graphite such as mesocarbon microbeads (MCMB) and highly oriented pyrolytic graphite (HOPG); or amorphous carbon such as hard carbon and soft carbon. The metal active material may be Al, Si, Sn, and an alloy containing at least one element of Al, Si, and Sn.

[0065] The adhesives contained in the first and second coatings are components for bonding the ingredients included in the first and second coatings, and may include butadiene rubber (BR), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or carboxymethyl cellulose (CMC).

[0066] The conductive material that ensures the conductivity of the electrode active material layer can be carbon black, conductive graphite, ethylene black, or graphene.

[0067] More specifically, the solid electrolyte can be an oxide-based solid electrolyte or a sulfide-based solid electrolyte, and preferably a sulfide-based solid electrolyte. The solid electrolyte can have a lithium-ion conductivity of 0.3 mS / cm or greater.

[0068] There are no particular limitations on sulfide-based solid electrolytes, but they may include Li₂S-P₂S₅, Li₂S-P₂S₅-LiI, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-LiBr, Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂S-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂S-SiS₂-P₂-B₂-LiI, Li₂S₅-LiI, Li₂S-B₂S₃, Li₂S₂-ZmSn (where "m" and "n" are positive numbers, and Z is one of Ge, Zn, and Ga), Li₂S-GeS₂, Li₂S-SiS₂-Li₃PO₄, Li₂S-SiS₂-Li x MO y (Where "x" and "y" are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In), or Li 10 GeP2S 12 .

[0069] All-solid-state batteries

[0070] This disclosure provides an all-solid-state battery including the electrodes described above for all-solid-state batteries.

[0071] More specifically, this disclosure provides an all-solid-state battery including electrodes for an all-solid-state battery and a solid electrolyte layer. The solid electrolyte layer may be situated between two different electrodes for the all-solid-state battery.

[0072] When the electrode of the all-solid-state battery is the positive electrode, the all-solid-state battery may include a positive electrode, a solid electrolyte layer, and a conventional negative electrode according to the present disclosure. When the electrode of the all-solid-state battery is the negative electrode, the all-solid-state battery may include a negative electrode, a solid electrolyte layer, and a conventional positive electrode according to the present disclosure.

[0073] When the electrodes used in an all-solid-state battery are positive and negative electrodes, the all-solid-state battery may include positive and negative electrodes according to the present disclosure, and a solid electrolyte layer between the positive and negative electrodes.

[0074] The solid electrolyte layer may include a solid electrolyte, a binder, and a conductive material included in the coating described above. To minimize interfacial resistance, the solid electrolyte, binder, and conductive material included in the solid electrolyte layer may be the same as those used in the first and second coatings described above.

[0075] Furthermore, in the all-solid-state battery provided in this disclosure, the thickness of the solid electrolyte layer is preferably in the range of 20 μm to 50 μm. When the solid electrolyte layer is too thin, it can lead to electrical short circuits or electrolyte rupture. When the solid electrolyte layer is too thick, the ionic conductivity and electronic conductivity decrease, thereby causing problems related to battery performance and stability.

[0076] Methods for fabricating electrodes for all-solid-state batteries

[0077] This disclosure provides a method for fabricating an electrode for an all-solid-state battery. More specifically, this disclosure provides a method for fabricating an electrode for an all-solid-state battery, the method comprising: forming a first coating on a current collector (S1); placing a mask on the first coating and forming a second coating (S2); and removing the mask (S3).

[0078] S1, forming a first coating (active material layer) on the current collector using conventional methods, which may include coating and drying a first coating slurry comprising an electrode active material, a conductive material, a binder, and a solid electrolyte on the current collector. The electrode active material, conductive material, binder, and solid electrolyte may be applied in the same manner as described above.

[0079] In S2, a mask can be placed on the first coating after the first coating is formed on the current collector and before the second coating is formed. The mask is a device to prevent the formation of the second coating. Therefore, the second coating can be selectively formed only in areas without a mask, rather than in areas covered by a mask.

[0080] The shape of the mask is not particularly limited, and the area where the mask is placed can be the area used to concentrate the pressure applied by the pressing member, as described below. More specifically, when the pressing member is a clamp, the area where the mask is placed can include the area used to place the axis of the clamp.

[0081] The mask should be made of a material that is not wetted or corroded by solvents, and this material can be varied depending on the solvent to be used. For example, the material may include at least one selected from the group consisting of polyethylene, polytetrafluoroethylene, and polyethylene naphthalate. The thickness of the mask is preferably in the range of 5 μm to 50 μm. When the mask is too thick or too thin, a smooth second coating may not be formed.

[0082] In S2, similar to the formation of the first coating, the second coating can be formed by applying and drying a second coating slurry comprising an electrode active material, a conductive material, a binder, and a solid electrolyte onto the first coating. The conductive material, binder, and solid electrolyte included in the second coating slurry can be applied in the same manner as described above.

[0083] Through S2, electrodes for all-solid-state batteries, including a first coating and a second coating formed in a partial region, can be prepared, and all-solid-state batteries can be prepared by utilizing the electrodes.

[0084] Preparation method of all-solid-state battery

[0085] This disclosure provides a method for preparing all-solid-state batteries using the electrodes described above for all-solid-state batteries.

[0086] More specifically, this disclosure provides a method for fabricating an all-solid-state battery, the method comprising sequentially stacking the electrodes, a solid electrolyte layer, and a counter electrode described above for an all-solid-state battery, and rolling the stacked structure using a pressing member. The pressing member is placed on the region of the electrodes for the all-solid-state battery that does not have a second coating.

[0087] As described above, the second coating of the electrode for an all-solid-state battery according to this disclosure can be formed in an area that does not receive any pressure. Therefore, a pressing member that applies pressure can be placed on an area that does not have the second coating.

[0088] Furthermore, in the method for preparing an all-solid-state battery according to this disclosure, when the electrode used in the all-solid-state battery is a positive electrode, the opposite electrode can be a negative electrode. When the electrode used in the all-solid-state battery is a negative electrode, the opposite electrode can be a positive electrode. In addition, both the positive and negative electrodes of the all-solid-state battery can be the electrodes used in the all-solid-state battery according to this disclosure.

[0089] There are no particular limitations on the pressing component, as long as it is used for rolling all-solid-state batteries, and it can be, for example, a clamp with multiple axes. The clamp can be a four-axis, six-axis, nine-axis, or 12-axis clamp. When a four-axis or six-axis clamp is used as a clamp, the area without the second coating can be the center of the electrode because the pressure is concentrated at the center. When a nine-axis or 12-axis clamp is used as a clamp, the area without the second coating can be the area of ​​the axis used to place the clamp.

[0090] Embodiments of this disclosure will be described in more detail below. However, the following embodiments are provided for illustrative purposes only, and the scope of this disclosure is not limited thereto.

[0091] Example 1

[0092] A cathode slurry was prepared by mixing an NCM-based positive electrode active material, an azide-based solid electrolyte (LPSCl(Br)), and a butadiene rubber (BR) binder with an inorganic solvent. The positive electrode slurry was then coated and dried onto a prepared aluminum current collector to form a first coating. Subsequently, a mask was placed on the first coating to... Figure 1 A second coating is formed at the indicated location. The positive electrode slurry is applied again and dried to form the second coating. Subsequently, a positive electrode for an all-solid-state battery without a second coating at the center of the electrode is prepared by removing the mask.

[0093] According to the above process, the area of ​​the mask application area is 25% of the area of ​​the area with the first coating (the area of ​​the area with the second coating is 75% of the area of ​​the area with the first coating), and the thickness of the second coating is 2.1% of the thickness of the first coating formed above.

[0094] Similar to the method used for the positive electrode in all-solid-state batteries, the negative electrode for all-solid-state batteries was prepared by using graphite as the negative electrode active material instead of the positive electrode active material. The thickness of the prepared positive electrode for all-solid-state batteries was 100 μm, while the thickness of the negative electrode for all-solid-state batteries was 50 μm. A solid electrolyte slurry was applied and dried on the prepared negative electrode to form a solid electrolyte layer on the negative electrode. The thickness of the solid electrolyte layer was 30 μm. The prepared positive electrode, solid electrolyte layer, and negative electrode of the all-solid-state battery were stacked sequentially, and the stacked structure was pressed using a six-axis clamp to prepare the all-solid-state battery.

[0095] Example 2

[0096] The all-solid-state battery was prepared in the same manner as in Example 1, except that the thickness of the second coating was less than 2% of the thickness of the first coating.

[0097] Example 3

[0098] All-solid-state batteries were prepared in the same manner as in Example 1, except that the area of ​​the mask used was less than 20% of the area of ​​the region with the first coating.

[0099] Example 4

[0100] All-solid-state batteries were prepared in the same manner as in Example 1, except that the area of ​​the mask used was greater than 30% of the area of ​​the region with the first coating.

[0101] Example 5

[0102] All-solid-state batteries were prepared in the same manner as in Example 1, except that the mask was used only for the positive electrode and not for the negative electrode.

[0103] Example 6

[0104] All-solid-state batteries were prepared in the same manner as in Example 1, except that the mask was used only for the negative electrode and not for the positive electrode.

[0105] Comparative example

[0106] Without using the mask in Example 1, the positive electrode, negative electrode, and solid electrolyte layer are formed to have equal thickness, stacked sequentially, and pressed together using the same jig to prepare an all-solid-state battery.

[0107] The positive and negative electrodes prepared in the examples and comparative examples are summarized in Table 1 below. In Table 1, "gradation electrode" refers to an electrode prepared using a mask.

[0108] Table 1

[0109]

[0110] Experimental Example 1: Determining the capacity retention of an all-solid-state battery

[0111] For the all-solid-state batteries prepared in the examples and comparative examples, the capacity retention after 50 cycles was confirmed. The capacity retention was calculated by performing three cycles at 0.05C and repeating charge / discharge cycles at 0.2C. The discharge capacity of the first cycle was then compared with the discharge capacity of the 50th cycle to calculate the capacity retention. The results are summarized in Table 2 below.

[0112] Table 2

[0113] Capacity retention rate (%) Example 1 88 Example 2 73 Example 3 83 Example 4 82 Example 5 79 Example 6 82 Comparative example 72

[0114] As can be recognized from the results shown in Table 2 above, all-solid-state batteries exhibit improved performance in terms of capacity retention when they include a gradient electrode comprising a second coating formed on a portion of the first coating. In particular, it can be appreciated that electrode durability can be further increased during electrode fabrication and actuation when the second coating is formed only in the areas other than those subjected to pressure by the concentration clamp.

[0115] As described above, according to this disclosure, the electrode for an all-solid-state battery has a structure in which two coatings, a first coating and a second coating, are sequentially stacked on a current collector. During battery assembly and operation, the all-solid-state battery has a structure in which the first coating is selectively formed only in regions where concentrated pressure is applied. Therefore, surface pressure can be minimized during battery assembly and operation, thereby preventing degradation of the surface properties of the all-solid-state battery and dendrite formation, thus improving the durability and performance of the all-solid-state battery.

[0116] While this disclosure has been described above with reference to exemplary embodiments and accompanying drawings, it is not limited thereto. Various modifications and alterations may be made by those skilled in the art to which this disclosure pertains without departing from the spirit and scope of this disclosure as claimed in the appended claims.

Claims

1. An electrode for an all-solid-state battery, the electrode comprising: Current collector; A first coating is formed on the current collector; as well as A second coating is formed on a portion of the first coating.

2. The electrode of claim 1, wherein the region having the first coating but not the second coating is surrounded by the region having the second coating.

3. The electrode according to claim 1, wherein the ratio of the thickness of the second coating to the thickness of the first coating is in the range of 1% to 5%.

4. The electrode according to claim 1, wherein the ratio of the area of ​​the region having the second coating to the area of ​​the region having the first coating is in the range of 60% to 90%.

5. The electrode according to claim 1, wherein the ratio of the loading level of the electrode active material in the second coating to the loading level of the electrode active material in the first coating is at least 2%.

6. The electrode according to claim 1, wherein the first coating comprises an electrode active material, a binder, and a solid electrolyte.

7. The electrode according to claim 1, wherein the second coating comprises an electrode active material, a binder, and a solid electrolyte.

8. The electrode of claim 1, wherein the pressing member is placed on a region of the electrode that does not have a second coating.

9. An all-solid-state battery, comprising: The electrode for an all-solid-state battery according to claim 1; as well as Solid electrolyte.

10. A method for fabricating an electrode for an all-solid-state battery, the method comprising: A first coating (S1) is formed on the current collector; A mask is placed on the first coating and a second coating is formed (S2); as well as Remove the mask (S3).

11. The method of claim 10, wherein the mask comprises at least one material selected from the group consisting of polyethylene, polytetrafluoroethylene, and polyethylene naphthalate.

12. The method of claim 10, wherein the mask has a thickness in the range of 5 μm to 50 μm.

13. The method of claim 10, wherein S1 comprises: A first coating slurry comprising electrode active material, conductive material, binder and solid electrolyte is coated and dried on the current collector.

14. The method of claim 10, wherein S2 comprises: A second coating slurry comprising electrode active material, conductive material, binder and solid electrolyte is applied to and dried on the first coating.

15. A method for preparing an all-solid-state battery, the method comprising: The electrodes, solid electrolyte layer, and counter electrode for all-solid-state batteries according to claim 1 are stacked sequentially. as well as A pressing and stacking structure using pressing components. The pressing member is placed on the area of ​​the electrode for the all-solid-state battery that does not have a second coating.

16. The method of claim 15, wherein the electrode for the all-solid-state battery is a positive electrode, and The opposite electrode is the negative electrode.

17. The method of claim 15, wherein the electrode for the all-solid-state battery is a negative electrode, and The relative electrode is the positive electrode.

18. An all-solid-state battery, comprising: An electrode, the electrode comprising a current collector, a first coating formed on the current collector, a second coating formed on a portion of the first coating, and a conductive material layer formed on a portion of the second coating, wherein the conductive material layer is configured to enhance the conductivity between the second coating and the solid electrolyte; A solid electrolyte layer located between the electrode and the opposite electrode; as well as A pressing member configured to apply pressure to the electrode, wherein the pressing member is placed on a region of the electrode where the second coating is absent.

19. The all-solid-state battery of claim 18, wherein the conductive material layer comprises at least one material selected from the group consisting of carbon black, conductive graphite, ethylene black, and graphene.

20. The all-solid-state battery of claim 18, wherein the conductive material layer is selectively formed only in the region of the second coating that is in direct contact with the solid electrolyte layer.

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