Method for manufacturing oxide-based stacked ceramic all-solid-state battery and all-solid-state battery manufactured thereby

Abstract

The present invention relates to a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery, comprising the steps of: (A) manufacturing a laminate including an anode layer, an oxide-based solid electrolyte layer, and a cathode layer; (B) pressing the laminate; (C) heating the pressed laminate to degrease it; and (D) pressing the degrease-based laminate. According to the present invention, a chemical reaction between the electrode material and the electrolyte is minimized during the manufacturing process of the all-solid-state battery through a low-temperature degreasing process that replaces the conventional high-temperature sintering process, and the density and contact characteristics of each layer are improved through a pressurization process, thereby simultaneously improving the ionic conductivity and electronic conductivity of the all-solid-state battery, so that an all-solid-state battery can be manufactured with significantly improved initial charge / discharge characteristics and long-term charge / discharge cycle life.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing an all-solid-state battery, and more specifically, to a method for manufacturing a multilayer ceramic all-solid-state battery by stacking a positive electrode material, a negative electrode material, and an oxide-based solid electrolyte, and to an all-solid-state battery manufactured thereby. Background Technology

[0002] Based on their high energy density and excellent reversibility, lithium-ion batteries are widely used in various energy storage applications, such as electronic devices and electric vehicles.

[0003] However, conventional liquid electrolyte-based lithium-ion batteries have several drawbacks due to their reliance on liquid electrolytes. In particular, electrolyte decomposition during operation can release toxic gases, and there is a risk of abnormal overheating and ignition in the event of a short circuit. Furthermore, they have limitations in that their performance inevitably degrades in extreme environments due to a restricted operating temperature range.

[0004] To address these issues, all-solid-state lithium-ion batteries, which replace liquid electrolytes with solid ones, are attracting attention as a new alternative. All-solid-state batteries overcome the stability problems of liquid electrolytes while providing high energy density and a wide operating temperature range.

[0005] In particular, oxide-based solid electrolytes offer superior safety compared to sulfide-based solid electrolytes, which pose a risk of generating toxic H₂S by reacting with moisture in the air, as they can operate stably in air and do not exhibit toxic reactions. Due to these characteristics, oxide electrolyte-based all-solid-state battery technology is continuously advancing, and major Japanese manufacturers of multi-layer ceramic capacitors (MLCCs) have developed small all-solid-state multi-layer ceramic batteries (MLCBs) based on this technology.

[0006] MLCBs enable the realization of wearable devices and Internet of Things (IoT) devices thanks to their miniaturized design, high energy density, non-flammability, and ability to be mounted on PCBs. In particular, they are safer and more durable than conventional lithium-ion batteries, making them suitable for use in environments close to the human body.

[0007] Meanwhile, MLCBs developed in Japan are often designed with a symmetrical structure, which allows the same electrode active material to perform both oxidation and reduction reactions without the roles of the anode and cathode being fixed.

[0008] Although MLCBs with such symmetric structures offer advantages such as simplified design and manufacturing processes and improved stability, several disadvantages are becoming apparent. Specifically, MLCBs with symmetric structures may have lower energy density compared to conventional lithium-ion batteries, and there is a possibility of reduced electrochemical efficiency. Additionally, because the electrode active material undergoes repeated oxidation and reduction reactions during the charging and discharging process, material degradation proceeds rapidly, posing a risk of shortened charge-discharge cycle life. Furthermore, there are limitations in that they may not provide sufficient performance in applications requiring high power output.

[0009] Attempts are being made to develop MLCBs based on traditional anode / electrolyte / cathode structures to solve the problems associated with MLCBs of this symmetric structure, but development is facing difficulties due to various problems as follows.

[0010] Specifically, MLCBs with an anode / electrolyte / cathode structure are fabricated as a multilayer structure containing an anode, a cathode, and a solid electrolyte, undergoing a process of sintering them at high temperatures (approximately 700°C or higher) to tightly bond them; however, during this process, there is a high probability of chemical reactions occurring between the anode, cathode, and solid electrolyte. Such reactions can alter the inherent properties of each material and cause degradation, leading to a decline in battery performance. For example, the conductivity of the anode material decreases due to reaction with the electrolyte, while the cathode material is at risk of corrosion in high-temperature environments. In particular, if the properties of the solid electrolyte change or degrade, ionic conductivity drops significantly, and changes in the crystal structure of the anode and cathode materials reduce energy density and efficiency, negatively impacting battery life.

[0011] Furthermore, solid electrolytes, which serve as pathways for lithium ions, have relatively lower ionic conductivity compared to liquid electrolytes, which can lead to slower charge / discharge rates or reduced output performance. Additionally, at the interface where the anode and cathode meet the solid electrolyte, ion flow is hindered, resulting in increased interfacial resistance. This increase in interfacial resistance raises the battery's overall resistance, causing energy loss and degrading battery performance. In particular, if cracks or voids form due to misalignment at the interface, the ion transport pathway is severed, which can significantly impair battery stability and operational efficiency. Prior art literature

[0012] Korean Published Patent No. 10-2022-0008056 (Date of publication: January 20, 2022) The problem to be solved

[0013] The technical problem that the present invention aims to solve is to provide a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery and an all-solid-state battery manufactured thereby, which prevents material degradation caused by chemical reactions between electrodes and electrolytes occurring during the high-temperature sintering process when manufacturing an all-solid-state multilayer ceramic battery (MLCB) with a positive electrode / electrolyte / negative electrode structure, and can improve problems caused by the low ionic conductivity of the solid electrolyte. means of solving the problem

[0014] To achieve the above technical objective, the present invention proposes a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery, comprising the steps of: (A) manufacturing a laminate including an anode layer, an oxide-based solid electrolyte layer, and a cathode layer; (B) pressing the laminate; (C) heating the pressed laminate to degrease it; and (D) pressing the degrease-treated laminate.

[0015] In addition, the above step (A) comprises: (A-1) a step of preparing a slurry containing a positive electrode active material, a slurry containing a negative electrode active material, and a slurry containing an oxide-based solid electrolyte, respectively; (A-2) a step of preparing a positive electrode layer, a negative electrode layer, and an oxide-based solid electrolyte layer, respectively by applying the slurry containing the positive electrode active material, the slurry containing the negative electrode active material, and the slurry containing the oxide-based solid electrolyte, respectively onto a substrate; and (A-3) a step of stacking the positive electrode layer, the oxide-based solid electrolyte layer, and the negative electrode layer, thereby proposing a method for manufacturing an oxide-based stacked ceramic all-solid-state battery.

[0016] In addition, a method for manufacturing an oxide-based stacked ceramic all-solid-state battery is proposed, characterized in that the slurry containing the positive electrode active material and the slurry containing the negative electrode active material in step (A-1) further include an oxide-based solid electrolyte.

[0017] Additionally, in step (A-1), the positive active material is lithium manganese oxide (LiMn2O4, LMO), and the negative active material is lithium titanium oxide (Li4Ti5O). 12 , LTO), and the oxide-based solid electrolyte is lithium aluminum titanium phosphate (Li 1.3 Al 0..3 Ti 1.7 A method for manufacturing an oxide-based multilayer ceramic all-solid-state battery is proposed, characterized by being (PO4)3 (LATP).

[0018] In addition, a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery is proposed, characterized by performing the process of pressurizing the laminate at 80 to 90°C and 10 to 15 MPa twice in step (B).

[0019] In addition, a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery is proposed, characterized by heating the laminate to 200~300℃ in step (C) to degrease it.

[0020] In addition, a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery is proposed, characterized by pressing the laminate at 100 to 120°C and 20 to 30 MPa in step (D).

[0021] In addition, in another aspect of the invention, the present invention proposes an oxide-based stacked ceramic all-solid-state battery manufactured by the above method. Effects of the invention

[0022] According to the method for manufacturing an oxide-based stacked ceramic all-solid-state battery of the present invention, chemical reactions between the electrode material and the electrolyte are minimized during the all-solid-state battery manufacturing process through a low-temperature degreasing process that replaces the conventional high-temperature sintering process, and the density and contact characteristics of each layer are improved through a pressurization process, thereby simultaneously improving the ionic conductivity and electronic conductivity of the all-solid-state battery, so that an all-solid-state battery with significantly improved initial charge / discharge characteristics and long-term charge / discharge cycle life can be manufactured. Brief explanation of the drawing

[0023] FIG. 1 shows the cathode material (LiMn2O4, LMO) and anode material (Li4Ti5O) synthesized in the present embodiment. 12 , LTO) and solid electrolyte (Li 1.3 Al 0..3 Ti 1.7 These are the X-ray diffraction (XRD) pattern and scanning electron microscope (SEM) image of (PO4)3 (LATP). FIG. 2 is a schematic diagram showing the slurry preparation process and the tape casting process for manufacturing the anode layer, cathode layer, and solid electrolyte layer in the present embodiment. Figure 3 is a photograph of an anode composite electrode sheet, a solid electrolyte sheet, and a cathode composite electrode sheet manufactured by tape casting in the present embodiment. FIG. 4 is a schematic diagram showing the process of printing a current collector pattern, manufacturing a laminated sheet green body, and applying pressure in an embodiment of the present invention. Figure 5 shows the results of Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD) analysis for each of the anode composite electrode and cathode composite electrode that underwent a secondary pressurization and degreasing process in the present embodiment. Figure 6 is the result of analyzing the cross-section of an all-solid-state battery before and after the third pressurization process in the present embodiment using SEM / EDS. FIG. 7 is a Nyquist plot of solid electrolytes prepared by low-temperature degreasing, low-temperature degreasing and pressurization, and high-temperature sintering at 800°C, respectively, in the present embodiment. FIG. 8 shows the performance evaluation results of a stacked ceramic all-solid-state battery according to the presence or absence of a third pressurization process in an embodiment of the present invention (a: initial charge characteristics before and after the pressurization process, b: initial charge and discharge characteristics of the all-solid-state battery with the pressurization process applied, c: discharge cycle evaluation of the all-solid-state battery with the pressurization process applied). Specific details for implementing the invention

[0024] In describing the present invention, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the invention, such detailed description will be omitted.

[0025] Since embodiments according to the concept of the present invention may be subject to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0026] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to specify the existence of the described features, numbers, steps, actions, components, parts, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0027] The present invention relates to a method for manufacturing an oxide-based multilayer ceramic all-solid-state battery in which the bonding characteristics between the solid electrolyte and the electrode are improved, and the initial charge / discharge characteristics and long-term charge / discharge cycle life are significantly improved, in order to prevent chemical reactions and material degradation between the electrode and the electrolyte that may occur during the conventional high-temperature sintering process when manufacturing an all-solid-state battery, and to maximize the performance of the all-solid-state battery by improving the problem of low ionic conductivity of the solid electrolyte, by manufacturing a laminate composed of a positive electrode layer, an oxide-based solid electrolyte layer, and a negative electrode layer, and sequentially performing a low-temperature degreasing process and a pressurization process thereon.

[0028] A method for manufacturing an oxide-based laminated ceramic all-solid-state battery according to the present invention comprises: (A) a step of manufacturing a laminate including a positive electrode layer, an oxide-based solid electrolyte layer, and a negative electrode layer; (B) a step of pressurizing the laminate; (C) a step of heating the pressurized laminate to degrease it; and (D) a step of pressurizing the degreased laminate.

[0029] In the above step (A), an anode layer, a cathode layer, and an oxide-based solid electrolyte layer are manufactured and a laminate is manufactured therefrom, for example, (A-1) a step of manufacturing a slurry containing an anode active material, a slurry containing a cathode active material, and a slurry containing an oxide-based solid electrolyte, respectively; (A-2) a step of manufacturing an anode layer, a cathode layer, and an oxide-based solid electrolyte layer, respectively by applying the slurry containing an anode active material, the slurry containing a cathode active material, and the slurry containing an oxide-based solid electrolyte, respectively onto a substrate; and (A-3) a step of laminating the anode layer, the oxide-based solid electrolyte layer, and the cathode layer.

[0030] The anode layer is formed by using a slurry containing an anode active material, a conductive material, a binder, and a solvent through tape casting, slip casting, spray coating, slot die coating, etc., and if necessary, an oxide-based solid electrolyte can be added to the slurry to form the anode layer into a composite electrode layer.

[0031] As the above-mentioned cathode active material, LiMn₂O₄ (LMO), which possesses high voltage and a stable structure, may be used. LMO operates stably at an operating voltage of approximately 4 V and provides excellent electrochemical stability and high output characteristics due to its spinel structure. However, the above-mentioned cathode active material in the present invention is not limited thereto, and various known cathode active materials other than LMO may be used. For example, LiCoO₂ (LCO), LiFePO₄ (LFP), and LiNi x Mn y Co (1-x-y) O2(NMC) [where 0 <x<1, 0<y<1, x+y<1], LiNi x Co y Al (1-x-y) O2(NCA) [where 0 <x<1, 0<y<1, x+y<1]와 같은 리튬 전이금속 산화물, Li₂MnO₃ 기반의 고망간 산화물, LiNi 0.5 Mn 1.5 High-voltage spinel-based oxides such as O4 (LNMO), or composites thereof, may be used. The above-mentioned cathode active material may be selected according to the design requirements of the all-solid-state battery, chemical compatibility with oxide-based solid electrolytes, energy density, output characteristics, and stability, and the present invention also includes combinations and modifications of such cathode active materials.

[0032] The cathode layer is formed by using a slurry containing a cathode active material, a conductive material, a binder, and a solvent through tape casting, slip casting, spray coating, slot die coating, etc., and if necessary, an oxide-based solid electrolyte can be added to the slurry to form the cathode layer into a composite electrode layer.

[0033] As the above-mentioned negative electrode active material, Li4Ti5O, which has excellent lithium ion insertion and extraction characteristics and structural stability, is used. 12 (LTO) may be used. LTO is a representative negative electrode active material that operates stably at low potentials and provides a long cycle life due to minimal volume change during the charge-discharge process. However, the negative electrode active material in the present invention is not limited thereto, and various known negative electrode active materials other than LTO may be used. For example, various materials including carbon-based materials such as graphite and hard carbon, metal-based alloys such as lithium metal, lithium silicon (Li-Si), and lithium tin (Li-Sn), lithium intercalated oxides such as TiO and LiTi₂O₂₄, or composites thereof are suitable as the negative electrode active material of the present invention. The positive electrode active material may be selected according to the design purpose of the all-solid-state battery, chemical compatibility with the solid electrolyte, energy density, output characteristics, and stability, and the present invention also includes combinations and modifications of such negative electrode active materials.

[0034] An oxide-based solid electrolyte layer is formed by using a slurry containing an oxide-based solid electrolyte, a binder, and a solvent through tape casting, slip casting, spray coating, slot die coating, etc.

[0035] The above oxide-based solid electrolyte is Li having a NASICON (Na Super Ionic Conductor) structure. 1.3 Al 0..3 Ti 1.7 Li including (PO4)3, etc. 1+x Al x Ti 2-x (PO4)3[where 0 <x<1]로 표시되는 LATP계 고체 전해질을 사용할 수 있다. LATP계 고체 전해질은 우수한 리튬 이온 전도도와 넓은 전기화학적 안정성 창을 제공하며, 산화물 기반 전해질로서 공기 중에서의 화학적 안정성이 높아 제조 및 취급이 용이하다. 그러나, 본 발명에 있어서 상기 산화물계 고체 전해질은 이에 한정되지 않으며, LATP 이외에도 공지된 다양한 산화물계 고체 전해질을 사용할 수 있다. 예를 들어, LAGP계 고체 전해질, LLTO계 고체 전해질, LLZO계 고체 전해질 또는 이들의 복합체 등이 본 발명의 고체 전해질로 적합하다. 상기 산화물계 고체 전해질은 전고체 전지의 설계 요구사항, 양극 및 음극 활물질과의 화학적 호환성, 이온 전도도, 전기화학적 안정성 및 기계적 특성에 따라 선택될 수 있으며, 본 발명은 이러한 고체 전해질의 조합 및 변형 또한 포함한다.

[0036] In step (B) above, a laminate comprising an anode layer, an oxide-based solid electrolyte layer, and a cathode layer is heated to a predetermined temperature and then pressurized to ensure the structural stability of the laminate, increase the interlayer density, and improve the interlayer bonding strength.

[0037] For example, in step (B), the process of pressurizing the laminate at 80 to 90°C and 10 to 15 MPa may be performed twice to achieve optimal bonding while maintaining the chemical and mechanical properties of each layer, but is not necessarily limited to the temperature, pressure, and number of times.

[0038] In step (C), the laminate is heated to a low temperature to perform a degreasing process. This step removes organic matter within the laminate, which is the primary purpose of the degreasing process, while simultaneously replacing the conventional high-temperature sintering process to suppress chemical reactions between the electrode and the electrolyte and contribute to improving interfacial stability between the solid electrolyte and the electrode.

[0039] For example, the degreasing process performed in step (C) can be carried out at 200 to 300°C, but unlike conventional high-temperature sintering processes, it is not necessarily limited to the above temperature range as long as it does not induce a chemical reaction between the electrode layer and the solid electrolyte layer.

[0040] Furthermore, if the low-temperature degreasing process in this step (C) is performed in an inert gas atmosphere in addition to an air atmosphere, material degradation can be prevented and structural deformation of the laminate can be minimized during cooling after degreasing.

[0041] Finally, in step (D), the laminate degreased at low temperature is further pressurized to further increase the density of the laminate, thereby securing mechanical strength and further improving ionic conductivity and electronic conductivity by reducing interfacial resistance. Through this, the all-solid-state battery manufactured according to the present invention exhibits excellent initial charge-discharge performance and significantly improved long-term charge-discharge cycle life.

[0042] For example, this step (D) can be performed by a process of pressurizing the degreased laminate at 100 to 120°C and 20 to 30 MPa, but it is not necessarily limited to the above temperature and pressure ranges, and the temperature and pressure ranges are not specifically limited as long as they do not cause material degradation or unnecessary chemical reactions due to the application of excessive temperature or pressure.

[0043] According to the method for manufacturing an oxide-based multilayer ceramic all-solid-state battery according to the present invention, by combining a low-temperature degreasing process that replaces the conventional high-temperature sintering process with a pressurizing process performed after the degreasing process, chemical reactions between the electrode and the electrolyte can be minimized, and the density and bonding characteristics of each layer can be maximized.

[0044] In addition, the all-solid-state battery manufactured according to the present invention provides high energy density, excellent stability, and a long lifespan, and is suitable for various applications such as electronic devices, electric vehicles, and wearable devices. The detailed conditions of each step in the manufacturing method can be adjusted according to the purpose of application, and the technical scope of the present invention includes various modifications and combinations.

[0045] The present invention will be described in more detail below with reference to examples.

[0046] The embodiments according to this specification may be modified in various different forms, and the scope of this specification is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more fully explain this specification to those with average knowledge in the art.

[0047] <Examples >

[0048] The manufacturing of the multilayer stacked ceramic all-solid-state battery (MLCB) according to the present invention was carried out by synthesizing a positive electrode material, a negative electrode material, and an oxide-based solid electrolyte, respectively, to prepare a slurry, and then stacking each layer using a tape casting process and screen printing.

[0049] First, the positive electrode material, the negative electrode material, and the solid electrolyte were synthesized separately.

[0050] Lithium manganese oxide (LiMn2O4, hereinafter LMO) was used as the cathode material. To synthesize it, lithium carbonate (Li2CO3) and manganese dioxide (MnO2) were stoichiometrically mixed and uniformly mixed by wet ball milling, followed by synthesis via a solid-state reaction. X-ray diffraction (XRD) analysis revealed that the synthesized LMO exhibited a pure crystal structure without secondary phases, and scanning electron microscopy (SEM) confirmed a uniform particle size and distribution (Fig. 1a).

[0051] As the cathode material, lithium titanium oxide (Li4Ti5O 12 Lithium carbonate (Li2CO3) and titanium oxide (TiO2) were stoichiometrically mixed and uniformly mixed by wet ball milling, followed by synthesis via a solid-state reaction. X-ray diffraction (XRD) analysis revealed that the synthesized LTO exhibited a pure crystal structure without secondary phases, and scanning electron microscopy (SEM) confirmed uniform particle size and distribution (Fig. 1b).

[0052] Lithium aluminum titanium phosphate (Li) used as a solid electrolyte 1.3 Al 0.3 Ti 1.7 (PO4)3 (hereinafter LATP) was synthesized using the sol-gel method. Aluminum isopropoxide (Al(OCH(CH3)2)3), lithium nitrate (LiNO3), titanium isopropoxide (Ti(OCH(CH3)2)4), and phosphoric acid (H3PO4) were mixed to form a sol, and LATP powder was prepared through heat treatment following gelation and drying processes. XRD analysis revealed that the synthesized LATP exhibited a pure crystal structure without secondary phases, and a uniform particle distribution was confirmed through SEM images (Fig. 1c).

[0053] Next, each slurry was prepared based on the synthesized cathode material, anode material, and solid electrolyte.

[0054] To manufacture the positive electrode and the negative electrode composite electrode, respectively, the positive electrode slurry was prepared by mixing LMO:LATP:binder (compound binder):conductive material (carbon black) in a mass ratio of 40:35:15:10, and the negative electrode slurry was prepared by mixing LTO:LATP:binder:conductive material in a mass ratio of 40:35:15:10. The solid electrolyte slurry was prepared by mixing LATP and a binder in a ratio of 85:15. Each slurry was uniformly mixed using a paste mixer, and toluene was added to adjust the viscosity (Fig. 2a).

[0055] Each manufactured slurry was applied onto a carrier film using a tape casting process with a double doctor blade to form a sheet with a thickness of 30 to 50 μm (Fig. 2b), and then cut to desired dimensions to manufacture an anode composite electrode sheet, a solid electrolyte sheet, and a cathode composite electrode sheet (Fig. 3).

[0056] Next, a current collector pattern conforming to specifications was printed onto the anode and cathode composite electrode sheets using a screen printing method with silver (Ag) paste (Fig. 4a). The fabricated electrolyte and composite electrode sheets were dried at 80°C to remove the organic solvent and then cut to the required size. The cut anode composite electrode sheet, solid electrolyte sheet, and cathode composite electrode sheet were stacked in sequence, and a first pressurization was performed by applying a pressure of 10 MPa. The bonded sheet stack was fabricated by punching a circular cell with a diameter of 10 mm (Fig. 4b). Next, a second pressurization was performed using a mold at 80°C and a pressure of 10 MPa for 10 minutes. Subsequently, a burn-out process was carried out in the atmosphere at 250°C for 24 hours (Fig. 4c).

[0057] After completing the second pressurization and degreasing process, the surface elemental distribution of the anode composite electrode and the cathode composite electrode was analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction analysis (XRD) was used to confirm whether a secondary phase was formed in the anode composite electrode and the cathode composite electrode during the degreasing process (Fig. 5).

[0058] Elemental mapping results confirmed that the active material (anode and cathode), solid electrolyte, and conductive material are evenly distributed within the composite electrode.

[0059] In addition, since the composite electrode has a structure in which two or more phases are mixed, X-ray diffraction analysis (XRD) was performed to identify the peaks of each phase, and the existing primary phase was observed at the main peak, confirming that the degreasing process was completed without the formation of a secondary phase.

[0060] After the degreasing process, a third pressurization process was carried out for 2 hours at a pressure of 20 MPa and a temperature of 100°C to improve the density of each layer and the contact characteristics between interfaces.

[0061] As shown in Fig. 6, after the pressurization process, the thickness of the all-solid-state battery was reduced from 214 μm to 180 μm, increasing the density by 15.9%, and the interlayer adhesion of the composite electrode and solid electrolyte was improved, so the effect of increasing the interlayer contact surface area can be expected.

[0062] To evaluate the ionic conductivity of the solid electrolyte, LATP solid electrolyte samples were prepared under three conditions: low-temperature degreasing, low-temperature degreasing and pressurization, and high-temperature sintering at 800°C. The ionic conductivity was measured using an impedance analyzer (frequency range 40 Hz to 5 MHz), and the results are shown in Fig. 7.

[0063] Referring to Fig. 7, the ionic conductivity of the solid electrolyte sample subjected to the pressurization process is 6.0 x 10⁻⁶, which is 39% higher than the sample before pressurization. -5 S·cm -1It was confirmed that the ionic conductivity of the electrolyte layer improved through the pressurization process, whereas the ionic conductivity decreased compared to the LATP sample sintered at high temperature at 800°C.

[0064] Figure 8 shows the performance evaluation results of a stacked ceramic all-solid-state battery depending on whether a third pressurization process is applied.

[0065] In the all-solid-state battery without the tertiary pressurization process, the initial charging time was very long, and the voltage change was unstable, failing to rise to the full charge voltage of 3V and causing a voltage drop in the middle. On the other hand, the battery sample that underwent the tertiary pressurization process showed a rapid increase in voltage during initial charging and reached 3V stably, confirming that the initial charging performance was significantly improved (Fig. 8a).

[0066] In addition, the voltage of the all-solid-state battery with the tertiary pressurization process increased stably to 3V during charging, and the charge capacity was measured at 83 mAh / g. During discharge, the voltage decreased steadily to 0.1V, and the discharge capacity was measured at 35 mAh / g (Fig. 8b). After evaluating 50 charge-discharge cycles, the discharge capacity of the battery decreased from an initial 35 mAh / g to a final 8 mAh / g (Fig. 8c). These results show that the application of the tertiary pressurization process contributed to significantly improving the initial charge-discharge performance of the all-solid-state battery, but suggest that further improvement is still needed in terms of long-term cycle life.

[0067] This embodiment describes in detail the manufacturing and performance optimization processes of an all-solid-state battery, and confirmed that the pressurization process and the low-temperature degreasing process significantly contribute to improving the battery's initial performance and ion conductivity. This technology is expected to make a significant contribution to the development of all-solid-state batteries with excellent safety and performance.

[0068] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

Claim 1 (A) a step of manufacturing a laminate comprising an anode layer, an oxide-based solid electrolyte layer, and a cathode layer; (B) a step of pressurizing the laminate at 10 to 15 MPa at 80 to 90°C; (C) a step of degreasing the pressurized laminate by heating it to 200 to 300°C; and (D) a step of pressurizing the degreasing laminate at 20 to 30 MPa at 100 to 120°C; comprising a method for manufacturing an oxide-based laminated ceramic all-solid-state battery. Claim 2 A method for manufacturing an oxide-based stacked ceramic all-solid-state battery according to claim 1, wherein step (A) comprises the following steps (A-1) to (A-3): (A-1) a step of preparing a slurry containing a positive electrode active material, a slurry containing a negative electrode active material, and a slurry containing an oxide-based solid electrolyte, respectively; (A-2) a step of preparing a positive electrode layer, a negative electrode layer, and an oxide-based solid electrolyte layer, respectively, by applying each of the slurry containing the positive electrode active material, the slurry containing the negative electrode active material, and the slurry containing the oxide-based solid electrolyte onto a substrate; and (A-3) a step of stacking the positive electrode layer, the oxide-based solid electrolyte layer, and the negative electrode layer. Claim 3 A method for manufacturing an oxide-based multilayer ceramic all-solid-state battery, wherein, in paragraph 2, the slurry containing the positive electrode active material and the slurry containing the negative electrode active material further comprise an oxide-based solid electrolyte. Claim 4 In paragraph 2, the positive electrode active material is lithium manganese oxide (LiMn2O4, LMO), and the negative electrode active material is lithium titanium oxide (Li4Ti5O 12 , LTO), and the oxide-based solid electrolyte is lithium aluminum titanium phosphate (Li 1.3 Al 0..3 Ti 1.7 A method for manufacturing an oxide-based multilayer ceramic all-solid-state battery characterized by being (PO4)3, LATP. Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 An oxide-based multilayer ceramic all-solid-state battery manufactured by the method described in any one of claims 1 to 4.

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