[go: up one dir, main page]

WO2024190592A1 - Électrode pour batterie secondaire, son procédé de production et batterie secondaire tout solide - Google Patents

Électrode pour batterie secondaire, son procédé de production et batterie secondaire tout solide Download PDF

Info

Publication number
WO2024190592A1
WO2024190592A1 PCT/JP2024/008731 JP2024008731W WO2024190592A1 WO 2024190592 A1 WO2024190592 A1 WO 2024190592A1 JP 2024008731 W JP2024008731 W JP 2024008731W WO 2024190592 A1 WO2024190592 A1 WO 2024190592A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrode
secondary battery
active material
electrode active
positive electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/008731
Other languages
English (en)
Japanese (ja)
Inventor
歩 田中
啓 角田
純一 池尻
英郎 山内
巌大郎 狩野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Electric Glass Co Ltd
Original Assignee
Nippon Electric Glass Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Electric Glass Co Ltd filed Critical Nippon Electric Glass Co Ltd
Priority to CN202480013014.9A priority Critical patent/CN120693696A/zh
Priority to JP2025506767A priority patent/JPWO2024190592A1/ja
Publication of WO2024190592A1 publication Critical patent/WO2024190592A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrode for a secondary battery, a method for producing the same, and an all-solid-state secondary battery using the electrode for the secondary battery.
  • the electrodes used in lithium-ion secondary batteries are made up of an electrode active material that absorbs and releases lithium ions during charging and discharging, a conductive additive that aids in electronic conduction, and a binder required to bind these to the base material that collects electricity.
  • binders used in this process include polyvinylidene fluoride and styrene butadiene rubber.
  • Patent Document 1 discloses a positive electrode for a secondary battery having a positive electrode active material layer that contains at least a positive electrode active material and a solid electrolyte.
  • the binder When the battery is exposed to high temperatures of 60°C or higher, the binder reacts with the electrolyte and swells, reducing its binding properties. This causes the electrode mixture to peel off from the base material used for collecting current, resulting in rapid deterioration of the battery.
  • the object of the present invention is to provide an electrode for a secondary battery, a manufacturing method thereof, and an all-solid-state secondary battery that can effectively increase the capacity of the secondary battery and has excellent charge/discharge cycle characteristics.
  • This article describes the electrodes for secondary batteries and their manufacturing methods that solve the above problems, as well as various aspects of all-solid-state secondary batteries.
  • the secondary battery electrode according to aspect 1 of the present invention is characterized by comprising a current collector and an electrode layer made of an electrode active material that essentially contains an electrode active material crystal and an amorphous phase, and a conductive assistant.
  • the electrode layer is substantially free of ⁇ ''-alumina, ⁇ -alumina, and NASICON crystals.
  • the electrode layer is composed of only inorganic materials.
  • the electrode layer is formed on both main surfaces of the current collector.
  • the method for manufacturing an electrode for a secondary battery according to aspect 5 of the present invention is a method for manufacturing an electrode for a secondary battery according to any one of aspects 1 to 4, characterized in that an electrode material layer containing an electrode active material precursor and a conductive assistant is formed on a main surface of a current collector, and the electrode layer is formed by firing the electrode material layer.
  • the all-solid-state secondary battery according to aspect 6 of the present invention is characterized in that it comprises a secondary battery electrode according to any one of aspects 1 to 4.
  • the present invention provides an electrode for a secondary battery, a manufacturing method thereof, and an all-solid-state secondary battery that can effectively increase the capacity of the secondary battery and has excellent charge/discharge cycle characteristics.
  • FIG. 1 is a schematic cross-sectional view showing an electrode for a secondary battery according to one embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view showing a secondary battery electrode according to another embodiment of the present invention.
  • FIG. 3 is a schematic cross-sectional view showing an all-solid-state secondary battery according to one embodiment of the present invention.
  • Fig. 1 is a schematic cross-sectional view showing a secondary battery electrode according to one embodiment of the present invention.
  • a secondary battery electrode 10 of this embodiment includes a current collector 2 and an electrode layer 3.
  • the electrode layer 3 is substantially composed of an electrode active material 4 and a conductive assistant 5.
  • Substantially consisting of electrode active material 4 and conductive assistant 5" means that the main components are electrode active material 4 and conductive assistant 5, and for example, that the total content of electrode active material 4 and conductive assistant 5 in electrode layer 3 is 99 mass% or more.
  • the current collector 2 is not particularly limited as long as it has electronic conductivity.
  • the current collector include metal materials such as aluminum, titanium, silver, copper, stainless steel, and alloys thereof.
  • the above metal materials may be used alone or in combination. These alloys are alloys containing at least one of the above metals.
  • the above metal materials have high electronic conductivity and are less likely to undergo chemical reactions during charging and discharging of the secondary battery, so that the capacity of the secondary battery can be effectively increased and the charging and discharging cycle characteristics are excellent.
  • the current collector 2 is made of aluminum or an alloy containing aluminum.
  • Aluminum or an alloy containing aluminum has a low density among metal materials, and therefore can effectively increase the capacity of the secondary battery.
  • the surface of the current collector made of aluminum or an alloy containing aluminum is carbon-coated. This can prevent the formation of a passive oxide film on the surface of the current collector 2 during firing of the electrode, and therefore the secondary battery has excellent cycle characteristics during charge and discharge.
  • the current collector 2 is preferably a metal foil.
  • Metal foil is flexible, which allows for a large contact area with the electrode layer, and when used as a secondary battery, it can be integrated with the extraction electrode, effectively increasing the capacity of the secondary battery and providing excellent cycle characteristics during charging and discharging.
  • the current collector is preferably made of foamed metal. Because foamed metal has a high specific surface area, it is possible to increase the contact area with the electrode layer, resulting in excellent cycle characteristics during charging and discharging of the secondary battery.
  • the thickness of the current collector 2 is preferably 10 nm or more and 100 ⁇ m or less.
  • the thickness of the current collector 2 is preferably 50 ⁇ m or less, and more preferably 30 ⁇ m or less. In this case, the energy density of the secondary battery can be further increased.
  • the thickness of the current collector 2 is preferably 30 nm or more, and more preferably 50 nm or more. In this case, the increase in the internal resistance of the battery due to the decrease in conductivity and the decrease in discharge capacity, as well as the resulting decrease in weight energy density and volume energy density, can be further suppressed.
  • the electrode active material 4 is a positive electrode active material or a negative electrode active material.
  • the electrode active material 4 is composed of electrode active material crystals (positive electrode active material crystals or negative electrode active material crystals) and an amorphous phase.
  • the positive electrode active material is not particularly limited as long as it is made of positive electrode active material crystals capable of absorbing and releasing alkali ions such as sodium ions and lithium ions and an amorphous phase, and functions as an electrode layer.
  • the positive electrode active material may be formed, for example, by firing a positive electrode active material precursor powder such as a glass powder. By firing the positive electrode active material precursor powder, positive electrode active material crystals are precipitated. In addition, an amorphous phase is formed together with the positive electrode active material crystals by firing. By forming the amorphous phase, the alkali ion conductivity in the electrode layer 3 can be improved. In addition, the adhesion between the current collector 2 and the electrode layer 3 can be improved.
  • the positive electrode active material crystal acting as the positive electrode active material is preferably a positive electrode active material crystal containing sodium, and examples thereof include sodium transition metal phosphate crystals containing Na, M (M is at least one transition metal element selected from Cr, Fe, Mn, Co, V, and Ni), P, and O.
  • Na 2 FeP 2 O 7 Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ), Na 4 Fe 5 (PO 4 ) 2 (P 2 O 7 ) 2 , Na 3.64 Fe 2.18 (P 2 O 7 ) 2 , Na 3 Fe 2 (P O 4 ) (P 2 O 7 ), NaFePO 4 , Na 2 MnP 2 O 7 , Na 4 Mn 3 (PO 4 ) 2 (P 2 O 7 ), Na 4 Mn 5 (PO 4 ) 2 (P 2 O 7 ) 2 , Na 3.64 Mn 2.18 (P 2 O 7 ) 2 , Na 3 V 2 (PO 4 ) 3 , NaNiPO 4 , Na 2 NiP 2 O 7 , Na 4 Ni 3 (PO 4 ) 2 (P 2 O 7 ), Na 4 Ni 5 (PO 4 ) 2 (P 2 O 7 ) 2 , Na 3.64 Ni 2.18 (P 2 O 7 ) 2 , Na 4 Ni 7 (PO 4 ) 6 , Na 3 Ni 3 (PO 4
  • the sodium transition metal phosphate crystal is preferred because it has a high capacity and excellent chemical stability.
  • triclinic crystals belonging to the space group P1 or P-1 particularly crystals represented by the general formula Na x M y P 2 O z (1.2 ⁇ x ⁇ 2.8, 0.95 ⁇ y ⁇ 1.6, 6.5 ⁇ z ⁇ 8), are preferred because they have excellent cycle characteristics.
  • Other examples of the positive electrode active material crystal that acts as a positive electrode active material include layered sodium transition metal oxide crystals such as NaCrO 2 , Na 0.7 MnO 2 , and NaFe 0.2 Mn 0.4 Ni 0.4 O 2 .
  • the negative electrode active material is not particularly limited as long as it contains negative electrode active material crystals and an amorphous phase capable of absorbing and releasing alkali ions such as sodium ions and lithium ions, and functions as an electrode layer.
  • the negative electrode active material may be formed, for example, by firing a negative electrode active material precursor powder such as a glass powder. By firing the negative electrode active material precursor powder, negative electrode active material crystals are precipitated. Furthermore, by firing, an amorphous phase is formed together with the negative electrode active material crystals. By forming the amorphous phase, the alkali ion conductivity in the electrode layer 3 can be improved. In addition, the adhesion between the current collector 2 and the electrode layer 3 can be improved.
  • negative electrode active material crystals that act as negative electrode active materials include crystals containing at least one selected from Nb and Ti and O, metal crystals containing at least one selected from Sn, Bi, and Sb, and alloy crystals containing at least one selected from Sn, Bi, and Sb.
  • Crystals containing at least one selected from Nb and Ti and O are preferred because they have excellent cycle characteristics. Furthermore, when the crystals containing at least one selected from Nb and Ti and O contain Na and/or Li, the charge/discharge efficiency (ratio of discharge capacity to charge capacity) is increased, and a high charge/discharge capacity can be maintained, which is preferred.
  • crystals containing at least one selected from Nb and Ti and O are orthorhombic crystals, hexagonal crystals, cubic crystals, or monoclinic crystals, particularly monoclinic crystals belonging to the space group P21/m, which are more preferred because they are less likely to reduce capacity even when charged and discharged at a large current.
  • orthorhombic crystals examples include NaTi2O4 , etc.
  • hexagonal crystals examples include Na2TiO3 , NaTi8O13 , NaTiO2 , LiNbO3 , LiNbO2 , Li7NbO6 , Li2Ti3O7 , etc.
  • cubic crystals examples include Na2TiO3 , NaNbO3 , Li4Ti5O12 , Li3NbO4 , etc.
  • Examples of monoclinic crystals include Na2Ti6O13 , NaTi2O4 , Na2TiO3 , Na4Ti5O12 , Na2Ti4O9 , Na2Ti9O19 , Na2Ti3O7 , Na2Ti3O7 , Li1.7Nb2O5 , Li1.9Nb2O5 , Li12Nb13O33 , and LiNb3O8 .
  • Examples of monoclinic crystals belonging to the space group P21 / m include Na2Ti3O7 .
  • the crystals containing at least one selected from Nb and Ti and O preferably further contain at least one selected from B, Si, P, and Ge. These components facilitate the formation of an amorphous phase together with the negative electrode active material crystals, and have the effect of further improving sodium ion conductivity.
  • Other materials that can be used include metal crystals of at least one type selected from Sn, Bi, and Sb, alloy crystals containing at least one type selected from Sn, Bi, and Sb (e.g., Sn-Cu alloy, Bi-Cu alloy, Bi-Zn alloy), and glass containing at least one type selected from Sn, Bi, and Sb. These are preferred because they have high capacity and are less likely to decrease in capacity even when charged and discharged at a large current.
  • conductive carbon can be used as the conductive assistant 5.
  • conductive carbon include acetylene black, carbon black, ketjen black, vapor grown carbon fiber carbon conductive assistant (VGCF), carbon nanotubes, etc. It is preferable that the conductive assistant is such a carbon-based conductive assistant.
  • the content of the conductive assistant in the electrode layer 3 is, in mass %, preferably 0.05% or more, more preferably 0.1% or more, even more preferably 0.5% or more, particularly preferably 1% or more, and preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, particularly preferably 5% or less.
  • content of the conductive assistant in the electrode layer 3 is within the above range, it is possible to further improve ionic conductivity while ensuring high electronic conductivity within the electrode, and it is possible to further effectively improve the battery characteristics of the secondary battery.
  • the thickness of the electrode layer 3 is preferably in the range of 3 ⁇ m to 300 ⁇ m, and more preferably in the range of 10 ⁇ m to 150 ⁇ m. If the electrode layer 3 is too thin, the capacity of the secondary battery itself will be small, and the energy density may decrease. If the electrode layer 3 is too thick, the resistance to electronic conduction will be large, and the discharge capacity and operating voltage will tend to decrease.
  • the thickness of the electrode layer 3 is preferably in the range of 0.3 ⁇ m to 300 ⁇ m, and more preferably in the range of 3 ⁇ m to 150 ⁇ m. If the thickness of the electrode layer 3 is too thin, the absolute capacity (mAh) of the negative electrode tends to decrease. If the thickness of the electrode layer 3 is too thick, the resistance increases, and the capacity (mAh/g) tends to decrease.
  • the electrode layer 3 preferably does not substantially contain solid electrolytes such as ⁇ ''-alumina, ⁇ -alumina, and NASICON crystals. These solid electrolytes may reduce the sinterability of the electrode active material 4 and reduce the adhesion between the current collector 2 and the electrode layer 3 when the positive electrode active material precursor powder or the negative electrode active material precursor powder is fired to form the electrode active material crystals and amorphous phase.
  • solid electrolytes such as ⁇ ''-alumina, ⁇ -alumina, and NASICON crystals.
  • substantially free of solid electrolyte means that the content of solid electrolyte in electrode layer 3 is less than 1 mass %, for example.
  • the electrode layer 3 is preferably composed only of inorganic materials such as metal oxides, conductive carbon, and metals. If it contains organic materials such as binders, the binders will react with the electrolyte when the secondary battery is exposed to high temperatures of 60°C or higher, causing the binders to swell and reduce the binding properties, and the electrode mixture will peel off from the base material used for collecting current, causing the battery to deteriorate rapidly. In addition, the density of the electrode layer 3 will decrease, tending to reduce the discharge capacity.
  • inorganic materials such as metal oxides, conductive carbon, and metals. If it contains organic materials such as binders, the binders will react with the electrolyte when the secondary battery is exposed to high temperatures of 60°C or higher, causing the binders to swell and reduce the binding properties, and the electrode mixture will peel off from the base material used for collecting current, causing the battery to deteriorate rapidly. In addition, the density of the electrode layer 3 will decrease, tending to reduce the discharge capacity.
  • the ratio of the thickness of the electrode layer 3 to the thickness of the current collector 2 is preferably 1 or more, more preferably 2 or more, even more preferably 5 or more, and particularly preferably 10 or more, and is preferably 1000 or less, more preferably 500 or less, even more preferably 200 or less, and particularly preferably 100 or less.
  • the main surface of the current collector 2 has a structure with holes or is mesh-shaped.
  • the electrode layers 3 provided on both main surfaces of the current collector 2 can be fused together, further increasing adhesion and making it easier to homogenize the reaction distribution inside the electrode, thereby improving input/output characteristics.
  • the secondary battery electrode 10 of the present invention can be formed, for example, by forming an electrode material layer containing an electrode active material precursor (positive electrode active material precursor or negative electrode active material precursor) and a conductive assistant on one main surface of a current collector 2, and firing the electrode material layer to form the electrode layer 3.
  • the electrode material layer can be obtained, for example, by applying a paste containing an electrode active material precursor and a conductive assistant, and drying the paste.
  • the paste may contain a binder, a plasticizer, a solvent, or the like, as necessary.
  • the electrode material layer may be a powder compact.
  • the drying temperature of the paste is not particularly limited, but can be, for example, 40°C or higher and 120°C or lower.
  • the drying time of the paste is not particularly limited, but can be, for example, 3 minutes or higher and 600 minutes or lower.
  • the atmosphere during firing is preferably an inert atmosphere or a reducing atmosphere.
  • the firing temperature can be, for example, 400°C to 800°C, and the holding time at that temperature can be, for example, 1 minute to 2 hours.
  • the positive electrode active material precursor powder may contain, in terms of mole percent of oxide, 8% to 55% Na 2 O, 10% to 70% CrO+FeO+MnO+CoO+NiO, and 15% to 70% P 2 O 5 +SiO 2 +B 2 O 3 .
  • % means “mol %” unless otherwise specified.
  • ⁇ + ⁇ + means the total amount of the corresponding components.
  • Na 2 O is a source of sodium ions that move between the positive electrode active material and the negative electrode active material during charging and discharging.
  • the content of Na 2 O is preferably 8% to 55%, more preferably 15% to 45%, and even more preferably 25% to 35%. If the content of Na 2 O is too small, the amount of sodium ions that contribute to absorption and release tends to decrease, and the discharge capacity tends to decrease. On the other hand, if the content of Na 2 O is too large, heterogeneous crystals that do not contribute to charging and discharging, such as Na 3 PO 4, tend to precipitate, and the discharge capacity tends to decrease.
  • CrO, FeO, MnO, CoO, and NiO are components that act as a driving force for the absorption and release of sodium ions by causing a redox reaction due to the change in the valence of each transition element during charging and discharging.
  • NiO and MnO have a large effect of increasing the redox potential.
  • FeO is particularly easy to stabilize the structure during charging and discharging, and is easy to improve cycle characteristics.
  • the content of CrO+FeO+MnO+CoO+NiO is preferably 10% to 70%, more preferably 15% to 60%, even more preferably 20% to 55%, even more preferably 23% to 50%, particularly preferably 25% to 40%, and most preferably 26% to 36%.
  • each of the P 2 O 5 , SiO 2 and B 2 O 3 components is preferably 0% to 70%, more preferably 15% to 70%, further preferably 20% to 60%, and particularly preferably 25% to 45%.
  • various components can be added in addition to the above components to facilitate vitrification within a range that does not impair the effect as a positive electrode active material.
  • examples of such components include, in oxide notation, MgO, CaO, SrO, BaO, ZnO, CuO, Al 2 O 3 , GeO 2 , Nb 2 O 5 , TiO 2 , ZrO 2 , V 2 O 5 , and Sb 2 O 5 , and in particular, Al 2 O 3, which acts as a network-forming oxide, and V 2 O 5, which is an active material component, are preferred.
  • the content of the above components is preferably 0% to 30%, more preferably 0.1% to 20%, and even more preferably 0.5% to 10%, in total.
  • an amorphous phase is formed along with the positive electrode active material crystals.
  • the formation of the amorphous phase can improve the sodium ion conductivity in the electrode layer 3.
  • the adhesion between the current collector 2 and the electrode layer 3 can be improved.
  • the average particle size of the positive electrode active material precursor powder is preferably 0.01 ⁇ m to 15 ⁇ m, more preferably 0.05 ⁇ m to 12 ⁇ m, and even more preferably 0.1 ⁇ m to 10 ⁇ m. If the average particle size of the positive electrode active material precursor powder is too small, the positive electrode active material precursor powder will have a strong cohesive force, and will tend to have poor dispersibility when made into a paste. As a result, the internal resistance of the battery will increase and the operating voltage will tend to decrease. In addition, the electrode density will decrease, and the capacity per unit volume of the battery will tend to decrease. On the other hand, if the average particle size of the active material precursor powder is too large, sodium ions will be less likely to diffuse and the internal resistance will tend to increase. In addition, the surface smoothness of the electrode will tend to be poor.
  • the average particle size means D 50 (volume-based average particle size) and indicates a value measured by a laser diffraction scattering method.
  • the negative electrode active material precursor powder preferably contains, in terms of mole percent of oxide, 0% to 90% SnO, 0% to 90% Bi 2 O 3 , 0% to 90% TiO 2 , 0% to 90% Fe 2 O 3 , 0% to 90% Nb 2 O 5 , 0% to 90% SiO 2 +B 2 O 3 +P 2 O 5 5% to 75%, and 0% to 80% Na 2 O.
  • Sn ions, Bi ions, Ti ions, Fe ions, or Nb ions are more uniformly dispersed in the oxide matrix containing Si, B, or P.
  • Na 2 O the material becomes more excellent in sodium ion conductivity. As a result, it is possible to suppress the volume change when absorbing and releasing sodium ions, and it is possible to obtain a negative electrode active material with more excellent cycle characteristics.
  • SnO, Bi 2 O 3 , TiO 2 , Fe 2 O 3 and Nb 2 O 5 are negative electrode active material components that become sites for absorbing and releasing alkali ions.
  • the discharge capacity per unit mass of the negative electrode active material becomes larger, and the charge/discharge efficiency (ratio of discharge capacity to charge capacity) during the initial charge/discharge is more likely to be improved.
  • the content of these components is too high, the volume change associated with the absorption and release of sodium ions during charge/discharge cannot be alleviated, and cycle characteristics tend to deteriorate.
  • it is preferable to set the content range of each component as follows.
  • the SnO content is preferably 0% to 90%, more preferably 45% to 85%, even more preferably 55% to 75%, and particularly preferably 60% to 72%.
  • the content of Bi 2 O 3 is preferably 0% to 90%, more preferably 10% to 70%, further preferably 15% to 65%, and particularly preferably 25% to 55%.
  • the TiO2 content is preferably 0% to 90%, more preferably 5% to 72%, even more preferably 10% to 68%, even more preferably 12% to 58%, particularly preferably 15% to 49%, and most preferably 15% to 39%.
  • the content of Fe 2 O 3 is preferably 0% to 90%, more preferably 15% to 85%, even more preferably 20% to 80%, and particularly preferably 25% to 75%.
  • the content of Nb 2 O 5 is preferably 0% to 90%, more preferably 7% to 79%, even more preferably 9% to 69%, even more preferably 11% to 59%, particularly preferably 13% to 49%, and most preferably 15% to 39%.
  • the content of SnO+Bi 2 O 3 +TiO 2 +Fe 2 O 3 +Nb 2 O 5 is preferably 0% to 90%, more preferably 5% to 85%, and even more preferably 10% to 80%.
  • SiO2 , B2O3 and P2O5 are network-forming oxides that surround the sites in the negative electrode active material that store and release sodium ions, and thus further improve the cycle characteristics.
  • SiO2 and P2O5 not only further improve the cycle characteristics, but also have excellent sodium ion conductivity, and therefore have the effect of further improving the rate characteristics.
  • SiO 2 +B 2 O 3 +P 2 O 5 is preferably 5% to 85%, more preferably 6% to 79%, even more preferably 7% to 69%, even more preferably 8% to 59%, particularly preferably 9% to 49%, and most preferably 10% to 39%. If SiO 2 +B 2 O 3 +P 2 O 5 is too small, the volume change of the negative electrode active material component accompanying the absorption and release of sodium ions during charging and discharging cannot be alleviated, causing structural destruction, and the cycle characteristics tend to decrease. On the other hand, if SiO 2 +B 2 O 3 +P 2 O 5 is too large, the content of the negative electrode active material component becomes relatively small, and the charge and discharge capacity per unit mass of the negative electrode active material tends to become small.
  • the content of SiO2 is preferably 0% to 75%, more preferably 5% to 75%, even more preferably 7% to 60%, even more preferably 10% to 50%, particularly preferably 12% to 40%, and most preferably 20% to 35%. If the content of SiO2 is too high, the discharge capacity tends to decrease.
  • the content of P 2 O 5 is preferably 5% to 75%, more preferably 7% to 60%, even more preferably 10% to 50%, particularly preferably 12% to 40%, and most preferably 20% to 35%. If the content of P 2 O 5 is too low, it is difficult to obtain the above cycle characteristics. On the other hand, if the content of P 2 O 5 is too high, the discharge capacity is likely to decrease and the water resistance is likely to decrease. In addition, when an aqueous electrode paste is produced, unwanted heterogeneous crystals are generated and the P 2 O 5 network is broken, so that the cycle characteristics are likely to decrease.
  • the content of B 2 O 3 is preferably 0% to 75%, more preferably 5% to 75%, even more preferably 7% to 60%, even more preferably 10% to 50%, particularly preferably 12% to 40%, and most preferably 20% to 35%. If the content of B 2 O 3 is too high, the discharge capacity is likely to decrease and the chemical durability is likely to decrease.
  • an amorphous phase is formed along with the negative electrode active material crystals.
  • the formation of the amorphous phase can improve the sodium ion conductivity in the electrode layer 3.
  • the adhesion between the current collector 2 and the electrode layer 3 can be improved.
  • the average particle size of the negative electrode active material precursor powder is preferably 0.01 ⁇ m to 15 ⁇ m, more preferably 0.05 ⁇ m to 12 ⁇ m, and even more preferably 0.1 ⁇ m to 10 ⁇ m. If the average particle size of the negative electrode active material precursor powder is too small, the agglomeration force between the negative electrode active material precursor powders becomes strong, and dispersibility tends to be poor when made into a paste. As a result, the internal resistance of the battery increases and the operating voltage tends to decrease. In addition, the electrode density decreases, and the capacity per unit volume of the battery tends to decrease. On the other hand, if the average particle size of the negative electrode active material precursor powder is too large, sodium ions become difficult to diffuse and the internal resistance tends to increase. In addition, the surface smoothness of the electrode tends to be poor.
  • the electrode active material precursor powder is preferably prepared by melting and molding a raw material batch. This preparation method is preferable because it makes it easier to obtain an amorphous electrode active material precursor powder with excellent homogeneity.
  • the electrode active material precursor powder can be prepared as follows.
  • the raw materials are prepared to obtain a raw material batch having the desired composition.
  • the obtained raw material batch is then melted.
  • the melting temperature may be adjusted as appropriate so that the raw material batch is homogeneously melted.
  • the melting temperature is preferably 800°C or higher, and more preferably 900°C or higher.
  • the upper limit of the melting temperature it is preferably 1500°C or lower, and more preferably 1400°C or lower.
  • the obtained molten material is molded.
  • the molten material may be poured between a pair of cooling rolls and molded into a film while being rapidly cooled, or the molten material may be poured into a mold and molded into an ingot.
  • the obtained molded body is then pulverized to obtain an electrode active material precursor powder.
  • the electrode active material precursor powder may be produced by press-molding the raw material batch and then sintering it. Specifically, it can be produced as follows.
  • the raw materials are prepared to have the desired composition to obtain a raw material batch.
  • the obtained raw material batch is pre-calcined to obtain a pre-calcined raw material.
  • the pre-calcination temperature and pre-calcination time may be appropriately adjusted so that the raw material batch can be appropriately degassed.
  • the pre-calcination temperature is preferably 800°C or higher, and more preferably 900°C or higher.
  • the upper limit of the pre-calcination temperature it is preferably 1500°C or lower, and more preferably 1400°C or lower.
  • the obtained calcined raw material is pressure-molded to obtain a green compact.
  • the pressure for pressure molding may be appropriately adjusted so as to obtain a dense green compact.
  • the pressure is preferably 200 kgf/ cm2 or more, and more preferably 400 kgf/cm2 or more .
  • the obtained compact is sintered to obtain a sintered body.
  • the sintering temperature and sintering time may be adjusted as appropriate so that the compact reacts homogeneously.
  • the sintering temperature is preferably 800°C or higher, and more preferably 900°C or higher.
  • There is no particular upper limit to the sintering temperature but since a sintering temperature that is too high can lead to energy loss and evaporation of sodium components, etc., it is preferably 1500°C or lower, and more preferably 1400°C or lower.
  • the obtained sintered body is pulverized to obtain an electrode active material precursor powder.
  • (All-solid-state secondary battery) 3 is a schematic cross-sectional view showing an all-solid-state secondary battery according to one embodiment of the present invention. As shown in Fig. 3, the all-solid-state secondary battery 30 includes a current collector 2, an electrode layer 3, a solid electrolyte layer 34, a counter electrode layer 35, and a second current collector 36.
  • An electrode layer 3 is provided on both main surfaces of the current collector 2.
  • a solid electrolyte layer 34 is provided on the main surface of each electrode layer 3 opposite the current collector 2.
  • a counter electrode layer 35 is provided on the main surface of each solid electrolyte layer 34 opposite the electrode layer 3.
  • a second current collector 36 is provided on the main surface of each counter electrode layer 35 opposite the solid electrolyte layer 34. The second current collector 36 does not necessarily have to be provided.
  • the solid electrolyte constituting the solid electrolyte layer 34 is preferably formed from a sodium ion conductive oxide.
  • the sodium ion conductive oxide include compounds containing at least one selected from Al, Y, Zr, Si, and P, Na, and O.
  • Specific examples of the sodium ion conductive oxide include beta-alumina or NASICON crystal, which have excellent sodium ion conductivity.
  • the sodium ion conductive oxide is preferably at least one sodium ion conductive oxide selected from the group consisting of ⁇ ''-alumina, ⁇ -alumina, and NASICON crystal.
  • the sodium ion conductive oxide is more preferably ⁇ -alumina or ⁇ ''-alumina. These have even better sodium ion conductivity.
  • Beta alumina has two crystal forms, ⁇ -alumina (theoretical formula: Na 2 O ⁇ 11Al 2 O 3 ) and ⁇ ′′-alumina (theoretical formula: Na 2 O ⁇ 5.3Al 2 O 3 ).
  • ⁇ ′′-alumina is a metastable substance, and is usually used with Li 2 O or MgO added as a stabilizer.
  • ⁇ ′′-alumina has a higher sodium ion conductivity than ⁇ -alumina, it is preferable to use ⁇ ′′-alumina alone or a mixture of ⁇ ′′-alumina and ⁇ -alumina, and it is more preferable to use Li 2 O-stabilized ⁇ ′′-alumina (Na 1.7 Li 0.3 Al 10.7 O 17 ) or MgO-stabilized ⁇ ′′-alumina ((Al 10.32 Mg 0.68 O 16 )(Na 1.68 O)).
  • NASICON crystals include Na 3 Zr 2 Si 2 PO 12 , Na 3.2 Zr 1.3 Si 2.2 P 0.8 O 10.5 , Na 3 Zr 1.6 Ti 0.4 Si 2 PO 12 , Na 3 Hf 2 Si 2 PO 12 , Na 3.4 Zr 0.9 Hf 1.4 A 10.6 Si 1.2 P 1.8 O 12 , Na 3 Zr 1.7 Nb 0.24 Si 2 PO 12 , Na 3.6 Ti 0.2 Y 0.8 Si 2.8 O 9 , Na 3 Zr 1.88 Y 0.12 Si 2 PO 12 , Na 3.12 Zr 1.88 Y 0.12 Si 2 PO 12 , Na 3.05 Zr 2 Si 2.06 P 0.95 O 12 , Na 3.4 Zr 2 Si 2.4 P 0.6 O 12 , Na 3.4 Zr 1.9 Zn 0.1 Si 2.4 P 0.6 O 12 , Na 3.4 Zr 1.9 Mg 0.1 Si 2.2 P 0.8 O 12 , Na 2 .8 Zr 2 Si 2.4 P 0.6 O 12 , Na 3.6 Zr 0.13 Yb
  • the solid electrolyte layer 34 can be manufactured by mixing raw material powders, molding the mixed raw material powders, and then firing them. For example, it can be manufactured by forming a green sheet by turning the raw material powders into a slurry, and then firing the green sheet. It may also be manufactured by the sol-gel method.
  • the thickness of the solid electrolyte layer 34 is preferably 1 ⁇ m or more, more preferably 3 ⁇ m or more, even more preferably 5 ⁇ m or more, and preferably 1000 ⁇ m or less, more preferably 800 ⁇ m or less, and even more preferably 500 ⁇ m or less. If the thickness of the solid electrolyte layer 34 is too thin, the mechanical strength decreases and it becomes more susceptible to breakage, making it more likely for an internal short circuit to occur. If the thickness of the solid electrolyte layer 34 is too thick, the sodium ion conduction distance associated with charging and discharging becomes longer, increasing the internal resistance, and making it more likely for the discharge capacity and operating voltage to decrease. In addition, the energy density per unit volume of the all-solid-state secondary battery 30 also becomes more likely to decrease.
  • the solid electrolyte layer 34 may include a first solid electrolyte layer that is a dense layer and a second solid electrolyte layer that is a porous layer.
  • the first solid electrolyte layer and the second solid electrolyte layer may be made of the same material as the solid electrolyte layer 34.
  • the first solid electrolyte layer not only plays the role of a solid electrolyte, but also functions as a base layer to ensure the mechanical strength of the solid electrolyte layer 34. Therefore, the first solid electrolyte layer has a denser structure than the second solid electrolyte layer.
  • the first solid electrolyte layer has a smaller porosity than the second solid electrolyte layer.
  • the first solid electrolyte layer has a porosity defined by the following formula (1) of preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less.
  • the lower limit of the porosity is not particularly limited, but can be, for example, 0.1%.
  • p is the bulk density and p0 is the true density.
  • the thickness of the first solid electrolyte layer is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more, even more preferably 1 ⁇ m or more, particularly preferably 5 ⁇ m or more, preferably 300 ⁇ m or less, more preferably 200 ⁇ m or less, even more preferably 150 ⁇ m or less, and particularly preferably 100 ⁇ m or less. If the thickness of the first solid electrolyte layer is too small, the mechanical strength may decrease, or the electrode layer 3 and the counter electrode layer 35 may be short-circuited. On the other hand, if the thickness of the first solid electrolyte layer is too large, the ionic conductivity of the solid electrolyte layer 34 is likely to decrease. In addition, the energy density per unit volume of the all-solid-state secondary battery 30 tends to be high.
  • the second solid electrolyte layer is a porous layer having voids that are three-dimensionally connected to the solid electrolyte.
  • the electrode layer 3 and the counter electrode layer 35 are provided on the surface of the second solid electrolyte layer. Since the second solid electrolyte layer has voids that are three-dimensionally connected, the materials (active material powder, etc.) that make up the electrode layer 3 and the counter electrode layer 35 can easily enter the voids. Therefore, by providing the second solid electrolyte layer, which is a porous layer, on the first solid electrolyte layer, which is a dense layer, the adhesion between the solid electrolyte layer 34 and the electrode layer 3 and the counter electrode layer 35 can be increased.
  • the second solid electrolyte layer has a porosity defined by the above formula (1) of preferably 25% or more, more preferably 30% or more, even more preferably 40% or more, and preferably 97% or less, more preferably 95% or less, and even more preferably 90% or less.
  • a porosity defined by the above formula (1) preferably 25% or more, more preferably 30% or more, even more preferably 40% or more, and preferably 97% or less, more preferably 95% or less, and even more preferably 90% or less.
  • the thickness of the second solid electrolyte layer is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, even more preferably 5 ⁇ m or more, particularly preferably 10 ⁇ m or more, preferably 1000 ⁇ m or less, more preferably 800 ⁇ m or less, even more preferably 500 ⁇ m or less, particularly preferably 300 ⁇ m or less.
  • the thickness of the second solid electrolyte layer is too small, the amount of material constituting the electrode layer 3 and the counter electrode layer 35 that penetrates into the voids in the second solid electrolyte layer is reduced, so that the contact area between the solid electrolyte layer 34 and the electrode layer 3 and the counter electrode layer 35 is reduced, and adhesion is likely to decrease.
  • the ion conduction paths at the interfaces between the solid electrolyte layer 34 and the electrode layer 3 and the counter electrode layer 35 are reduced, so the internal resistance of the all-solid-state secondary battery 30 tends to increase. As a result, the rapid charge/discharge characteristics of the all-solid-state secondary battery 30 are likely to decrease.
  • the solid electrolyte layer 34 which includes a first solid electrolyte layer that is a dense layer and a second solid electrolyte layer that is a porous layer, can be formed, for example, by the method for manufacturing a solid electrolyte sheet described in WO 2021/045039.
  • the electrode active material contained in the counter electrode layer 35 is a negative electrode active material when the electrode active material contained in the electrode layer 3 of the secondary battery electrode 10 is a positive electrode active material, and is a positive electrode active material when the electrode active material contained in the electrode layer 3 of the secondary battery electrode 10 is a negative electrode active material.
  • the negative electrode active material contained in the counter electrode layer 35 is not particularly limited, but may be, for example, a carbon electrode material such as hard carbon or soft carbon.
  • the carbon electrode material is preferably hard carbon.
  • the negative electrode active material may contain metallic sodium or an alloy-based negative electrode active material capable of absorbing sodium, such as tin, bismuth, lead, or phosphorus. It is preferable that the counter electrode layer 35 is not metallic sodium or a negative electrode layer containing metallic sodium.
  • the counter electrode layer 35 containing the negative electrode active material may further contain a sodium ion conductive solid electrolyte and a conductive assistant.
  • the ratio of each material in the counter electrode layer 35 containing the negative electrode active material may be, for example, in mass %, 60% to 95% negative electrode active material, 5% to 35% sodium ion conductive solid electrolyte, and 0% to 5% conductive assistant.
  • the sodium ion conductive solid electrolyte may be, for example, the sodium ion conductive oxide described in the section on the solid electrolyte layer 34.
  • the conductive assistant may be, for example, one described in the section on the electrode layer 3.
  • the thickness of the counter electrode layer 35 containing the negative electrode active material is preferably 0.3 ⁇ m or more, more preferably 3 ⁇ m or more, even more preferably 10 ⁇ m or more, and preferably 500 ⁇ m or less, and more preferably 300 ⁇ m or less.
  • the thickness of the counter electrode layer 35 containing the negative electrode active material is equal to or greater than the above lower limit, the charge/discharge capacity of the all-solid-state secondary battery 30 can be further increased.
  • the thickness of the counter electrode layer 35 containing the negative electrode active material is too thick, the resistance to electronic conduction increases, and the discharge capacity and operating voltage of the all-solid-state secondary battery 30 may decrease.
  • the positive electrode active material contained in the counter electrode layer 35 is not particularly limited, but is preferably a positive electrode active material made of crystallized glass containing crystals represented by the general formula Na x M y P 2 O z (1 ⁇ x ⁇ 2.8, 0.95 ⁇ y ⁇ 1.6, 6.5 ⁇ z ⁇ 8, M is at least one selected from the group consisting of Fe, Ni, Co, Mn, and Cr).
  • M is at least one selected from the group consisting of Fe, Ni, Co, Mn, and Cr.
  • the positive electrode active material is made of crystallized glass containing crystals represented by the general formula Na x MP 2 O 7 (1 ⁇ x ⁇ 2, M is at least one selected from the group consisting of Fe, Ni, Co, Mn, and Cr).
  • a positive electrode active material crystal for example, Na 2 FeP 2 O 7 , Na 2 CoP 2 O 7 , Na 2 NiP 2 O 7, etc. can be used.
  • the counter electrode layer 35 containing the positive electrode active material may also contain a solid electrolyte and a conductive additive.
  • the ratio of each material in the counter electrode layer 35 containing the positive electrode active material can be, for example, in mass %, 30% to 95% positive electrode active material, 5% to 70% solid electrolyte, and 0% to 20% conductive additive.
  • the solid electrolyte the one described in the section on solid electrolyte layer 34 can be used.
  • conductive carbon can be used. Examples of conductive carbon include acetylene black, carbon black, ketjen black, vapor grown carbon fiber carbon conductive additive (VGCF), etc. It is preferable that the conductive additive is a carbon-based conductive additive made of the above-mentioned materials.
  • the thickness of the counter electrode layer 35 containing the positive electrode active material is preferably 10 ⁇ m or more, more preferably 50 ⁇ m or more, even more preferably 100 ⁇ m or more, and preferably 1000 ⁇ m or less, and more preferably 700 ⁇ m or less.
  • the thickness of the counter electrode layer 35 containing the positive electrode active material is equal to or greater than the above lower limit, the charge/discharge capacity of the all-solid-state secondary battery 30 can be further increased.
  • the counter electrode layer 35 containing the positive electrode active material is too thick, the resistance to electronic conduction increases, which may reduce the discharge capacity and operating voltage of the all-solid-state secondary battery 30, and the stress due to shrinkage during firing may increase, leading to peeling.
  • the material of the second current collector 36 is not particularly limited, but may be a metal material such as aluminum, titanium, silver, copper, stainless steel, or an alloy thereof.
  • the above metal materials may be used alone or in combination. These alloys are alloys containing at least one of the above metals.
  • the thickness of the second current collector 36 is not particularly limited, but may be 0.01 ⁇ m or more and 1000 ⁇ m or less.
  • the method for forming the second current collector 36 is not particularly limited, and examples of the method include physical vapor phase methods such as vapor deposition or sputtering, and chemical vapor phase methods such as thermal CVD, MOCVD, and plasma CVD. Other methods for forming the second current collector 36 include plating, the sol-gel method, and liquid phase film formation methods using spin coating. However, it is preferable to form the second current collector 36 on the counter electrode layer 35 by sputtering, as this provides excellent adhesion.
  • test Battery Assembly The obtained secondary battery electrode was placed on the bottom cover of a coin cell with the aluminum foil side facing down, and a separator made of a 16 mm diameter polypropylene porous film dried under reduced pressure at 70°C for 8 hours, metallic sodium as the counter electrode, and the top cover of the coin cell were laminated in this order on top of it to prepare a test battery.
  • the test battery was assembled in an environment with a dew point temperature of -70°C or lower.
  • the obtained test battery was CC (constant current) charged from the open circuit voltage to 4.5 V at 80 ° C., and the amount of electricity charged to the positive electrode composite per unit mass (initial charge capacity) was obtained.
  • CC discharge was performed from 4.5 V to 2 V, and the amount of electricity discharged from the electrode layer per unit mass (initial discharge capacity) was obtained.
  • the energy density of the electrode layer was obtained from the operating voltage and discharge capacity at the time of the initial discharge.
  • the "capacity retention rate" was evaluated as the ratio of the discharge capacity at the 50th cycle to the initial discharge capacity.
  • the C rate was set to 0.2 C. The results are shown in Table 1.
  • Electrode Layer Formation of Positive Electrode Layer (Electrode Layer)
  • the positive electrode paste was applied to a thickness of 80 ⁇ m on one main surface of a 20 ⁇ m thick aluminum foil current collector, and dried at 70° C. for 3 hours to form a positive electrode material layer.
  • the positive electrode material layer formed on the main surface of the current collector was punched out to a diameter of 11 mm using an electrode punching machine, and fired for 30 minutes under the conditions shown in Table 2 to form a positive electrode layer (electrode layer) on one main surface of the current collector, thereby obtaining an electrode for a secondary battery.
  • test Battery Assembly The obtained secondary battery electrode was placed on the bottom cover of a coin cell with the aluminum foil side facing down, and a separator made of a 16 mm diameter polypropylene porous film dried under reduced pressure at 70°C for 8 hours, metallic sodium as the counter electrode, and the top cover of the coin cell were laminated in this order on top of it to prepare a test battery.
  • the test battery was assembled in an environment with a dew point temperature of -70°C or lower.
  • Electrode Layer Formation of Positive Electrode Layer (Electrode Layer)
  • the positive electrode paste was applied to a thickness of 80 ⁇ m on one main surface of a 20 ⁇ m thick aluminum foil current collector, and dried at 70° C. for 3 hours to form a positive electrode material layer.
  • the positive electrode material layer formed on the main surface of the current collector was punched out to a diameter of 11 mm using an electrode punching machine, and fired for 30 minutes under the conditions shown in Table 3 to form a positive electrode layer (electrode layer) on one main surface of the current collector, thereby obtaining an electrode for a secondary battery.
  • test Battery Assembly The obtained secondary battery electrode was placed on the bottom cover of a coin cell with the aluminum foil side facing down, and a separator made of a 16 mm diameter polypropylene porous film dried under reduced pressure at 70°C for 8 hours, metallic sodium as the counter electrode, and the top cover of the coin cell were laminated in this order on top of it to prepare a test battery.
  • the test battery was assembled in an environment with a dew point temperature of -70°C or lower.
  • raw material powders were prepared using sodium carbonate (Na 2 CO 3 ), sodium metaphosphate (NaPO 3 ), nickel oxide (NiO), and orthophosphoric acid (H 3 PO 4 ) as raw materials to obtain the compositions shown in Table 4, and melted in an air atmosphere at 1200 to 1500° C. for 90 minutes. The melt was then poured between a pair of rotating rollers and shaped while being quenched to obtain a film-like glass having a thickness of 0.1 mm to 2 mm. The obtained film-like glass was pulverized using a ball mill and a planetary ball mill to obtain a glass powder (positive electrode active material precursor powder) having an average particle size (D 50 ) of 0.5 ⁇ m.
  • D 50 average particle size
  • Electrode Layer Formation of Positive Electrode Layer (Electrode Layer)
  • the positive electrode paste was applied to a thickness of 80 ⁇ m on one main surface of a 20 ⁇ m thick aluminum foil current collector, and dried at 70° C. for 3 hours to form a positive electrode material layer.
  • the positive electrode material layer formed on the main surface of the current collector was punched out to a diameter of 11 mm using an electrode punching machine, and fired for 30 minutes under the conditions shown in Table 4 to form a positive electrode layer (electrode layer) on one main surface of the current collector, thereby obtaining an electrode for a secondary battery.
  • test Battery Assembly The obtained secondary battery electrode was placed on the bottom cover of a coin cell with the aluminum foil side facing down, and a separator made of a 16 mm diameter polypropylene porous film dried under reduced pressure at 70°C for 8 hours, metallic sodium as the counter electrode, and the top cover of the coin cell were laminated in this order on top of it to prepare a test battery.
  • the test battery was assembled in an environment with a dew point temperature of -70°C or lower.
  • the obtained test battery was CC (constant current) charged from the open circuit voltage to 5.2 V at 80 ° C., and the amount of electricity charged to the positive electrode composite per unit mass (initial charge capacity) was obtained.
  • CC discharge was performed from 5.2 V to 2 V, and the amount of electricity discharged from the electrode layer per unit mass (initial discharge capacity) was obtained.
  • the energy density of the electrode layer was obtained from the operating voltage and discharge capacity at the time of the initial discharge.
  • the "capacity retention rate" was evaluated as the ratio of the discharge capacity at the 50th cycle to the initial discharge capacity.
  • the C rate was set to 0.2 C. The results are shown in Table 4.
  • the pre-firing raw material batch was pressurized at 500 kgf/cm 2 , and fired at 900°C for 12 hours in a nitrogen/hydrogen mixed atmosphere for Comparative Example 1 and in a nitrogen atmosphere for Comparative Examples 2 and 3 to obtain a sintered body.
  • the obtained sintered body was pulverized in a ball mill and a planetary ball mill to obtain a positive electrode active material precursor powder having an average particle size (D 50 ) of 0.5 ⁇ m.
  • Electrode Layer Formation of Positive Electrode Layer (Electrode Layer)
  • the positive electrode paste was applied to a thickness of 80 ⁇ m on one main surface of a 20 ⁇ m thick aluminum foil current collector, and dried at 70° C. for 3 hours to form a positive electrode layer.
  • the positive electrode layer formed on the main surface of the current collector was punched out to a diameter of 11 mm using an electrode punching machine, and a positive electrode layer (electrode layer) was formed on one main surface of the current collector to obtain an electrode for a secondary battery.
  • test Battery Assembly The obtained secondary battery electrode was placed on the bottom cover of a coin cell with the aluminum foil side facing down, and a separator made of a 16 mm diameter polypropylene porous film dried under reduced pressure at 70°C for 8 hours, metallic sodium as the counter electrode, and the top cover of the coin cell were laminated in this order on top of it to prepare a test battery.
  • the test battery was assembled in an environment with a dew point temperature of -70°C or lower.
  • the energy density of the electrode layer was 210 Wh/kg or more, and the capacity retention rate at 50 cycles was 67% or more.
  • the energy density of the electrode layer was 183 Wh/kg or less, and the capacity retention rate at 50 cycles was 23% or less.
  • Example 17 (a) Preparation of green sheet for forming first solid electrolyte layer Sodium carbonate (Na 2 CO 3 ), aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), zirconium oxide (ZrO 2 ), and yttrium oxide (Y 2 O 3 ) were used as raw materials, and raw material powder was prepared so that, in mole percent, Na 2 O 14.2%, Al 2 O 3 75.4%, MgO 5.4%, ZrO 2 4.9%, and Y 2 O 3 0.1% was obtained. The raw material powder was calcined at 1250 ° C. for 4 hours, and then pulverized to an average particle size of 2 ⁇ m.
  • the negative electrode paste was applied to the center of one main surface of a 38 mm square, 75 ⁇ m thick solid electrolyte layer so that the negative electrode paste was 33 mm square and 70 ⁇ m thick. Drying was performed in a thermostatic chamber at 80° C. for 1 hour. Then, firing was performed in an N 2 (99.99%) atmosphere at 800° C. for 2 hours to form a negative electrode.
  • the weight of the negative electrode was calculated by (weight of the laminate after the negative electrode formation) minus (weight of the solid electrolyte layer).
  • the weight of the hard carbon active material was calculated by multiplying the weight of the active material by 0.8.
  • the capacity of the hard carbon was calculated by setting the capacity of the hard carbon to 385 mAh/g. As a result, the capacity of the negative electrode was 0.3 mAh/cm 2 .
  • the weight of the positive electrode was calculated from (weight of the laminate after the positive electrode was formed) - (weight of the laminate before the positive electrode was formed) - (weight of the aluminum foil).
  • the weight of the Na 2 FeP 2 O 7 active material was calculated by multiplying the calculated weight of the support by the ratio of the active material among them, 0.865.
  • the capacity of the positive electrode was calculated by assuming the capacity of Na2FeP2O7 crystallized glass ( Na2FeP2O7 active material) to be the theoretical capacity of 97mAh/g. As a result, the capacity of the positive electrode was 0.5mAh/ cm2 .
  • the capacity of the negative electrode was divided by the capacity of the positive electrode to obtain the N/P ratio (negative electrode capacity/positive electrode capacity), which was 0.6.
  • the all-solid-state secondary battery of Example 17 had an energy density of 70 Wh/kg and a capacity retention rate of 95% after 50 cycles.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Physics & Mathematics (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

L'invention concerne une électrode pour une batterie secondaire qui permet d'augmenter efficacement la capacité d'une batterie secondaire et présente d'excellentes caractéristiques de cycle de charge/décharge, un procédé de production de l'électrode pour une batterie secondaire, et une batterie secondaire tout solide.　L'électrode pour batterie secondaire est caractérisée en ce qu'elle comprend : une couche d'électrode comprenant sensiblement un matériau actif d'électrode comprenant des cristaux de matériau actif d'électrode et une phase amorphe, et un agent auxiliaire conducteur ; et un collecteur de courant.
PCT/JP2024/008731 2023-03-13 2024-03-07 Électrode pour batterie secondaire, son procédé de production et batterie secondaire tout solide Pending WO2024190592A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202480013014.9A CN120693696A (zh) 2023-03-13 2024-03-07 二次电池用电极及其制造方法和全固态二次电池
JP2025506767A JPWO2024190592A1 (fr) 2023-03-13 2024-03-07

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2023038300 2023-03-13
JP2023-038300 2023-03-13

Publications (1)

Publication Number Publication Date
WO2024190592A1 true WO2024190592A1 (fr) 2024-09-19

Family

ID=92755681

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2024/008731 Pending WO2024190592A1 (fr) 2023-03-13 2024-03-07 Électrode pour batterie secondaire, son procédé de production et batterie secondaire tout solide

Country Status (3)

Country Link
JP (1) JPWO2024190592A1 (fr)
CN (1) CN120693696A (fr)
WO (1) WO2024190592A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017073457A1 (fr) * 2015-10-28 2017-05-04 日本電気硝子株式会社 Matériau actif d'électrode positive pour batterie secondaire au sodium-ion
WO2018235828A1 (fr) * 2017-06-21 2018-12-27 株式会社村田製作所 Matériau de sulfure de magnésium, matériau composite de sulfure de magnésium, élément d'électrode positive pour accumulateurs, matériau semi-conducteur à large bande interdite, accumulateur au magnésium et procédé de production de sulfure de magnésium de zinc
WO2019088139A1 (fr) * 2017-11-02 2019-05-09 国立大学法人東京大学 Électrode négative de batterie secondaire, batterie secondaire et procédés de fabrication de celles-ci
JP2019125547A (ja) * 2018-01-19 2019-07-25 日本電気硝子株式会社 固体電解質粉末、並びにそれを用いてなる電極合材及び全固体ナトリウムイオン二次電池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017073457A1 (fr) * 2015-10-28 2017-05-04 日本電気硝子株式会社 Matériau actif d'électrode positive pour batterie secondaire au sodium-ion
WO2018235828A1 (fr) * 2017-06-21 2018-12-27 株式会社村田製作所 Matériau de sulfure de magnésium, matériau composite de sulfure de magnésium, élément d'électrode positive pour accumulateurs, matériau semi-conducteur à large bande interdite, accumulateur au magnésium et procédé de production de sulfure de magnésium de zinc
WO2019088139A1 (fr) * 2017-11-02 2019-05-09 国立大学法人東京大学 Électrode négative de batterie secondaire, batterie secondaire et procédés de fabrication de celles-ci
JP2019125547A (ja) * 2018-01-19 2019-07-25 日本電気硝子株式会社 固体電解質粉末、並びにそれを用いてなる電極合材及び全固体ナトリウムイオン二次電池

Also Published As

Publication number Publication date
JPWO2024190592A1 (fr) 2024-09-19
CN120693696A (zh) 2025-09-23

Similar Documents

Publication Publication Date Title
US11404726B2 (en) All-solid-state sodium ion secondary battery
JP7616253B2 (ja) バイポーラ型全固体ナトリウムイオン二次電池
JP6460316B2 (ja) ナトリウムイオン電池用電極合材、及びその製造方法並びにナトリウム全固体電池
JP7499029B2 (ja) 全固体ナトリウムイオン二次電池
JP7596690B2 (ja) 全固体ナトリウムイオン二次電池及び全固体ナトリウムイオン二次電池の製造方法
CN110870123A (zh) 固体电解质片及其制造方法、以及全固体二次电池
JPWO2018131627A1 (ja) ナトリウムイオン二次電池用電極合材及びその製造方法
JP6870572B2 (ja) 固体電解質シートの製造方法
WO2024135655A1 (fr) Batterie rechargeable au sodium-ion entièrement solide
WO2024135593A1 (fr) Électrode négative pour batteries secondaires sodium-ion, et batterie secondaire sodium-ion
WO2024190592A1 (fr) Électrode pour batterie secondaire, son procédé de production et batterie secondaire tout solide
WO2018235575A1 (fr) Batterie rechargeable sodium-ion
WO2024135358A1 (fr) Élément de stockage d'énergie et batterie secondaire tout solide
WO2025173555A1 (fr) Procédé de fabrication de batterie entièrement solide, et batterie entièrement solide
WO2024135357A1 (fr) Élément de stockage d'énergie et batterie secondaire tout solide
WO2024135616A1 (fr) Feuille d'électrolyte solide et batterie secondaire à électrolyte solide
WO2023127546A1 (fr) Feuille d'électrolyte solide et son procédé de production
WO2023127717A1 (fr) Matériau d'électrode pour batterie tout solide, électrode pour batterie tout solide et son procédé de fabrication, et batterie tout solide et son procédé de fabrication
WO2025047274A1 (fr) Mélange d'électrodes pour batteries secondaires, électrode pour batteries secondaires entièrement solides, et batterie secondaire entièrement solide

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24770698

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2025506767

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2025506767

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 202480013014.9

Country of ref document: CN

WWP Wipo information: published in national office

Ref document number: 202480013014.9

Country of ref document: CN

NENP Non-entry into the national phase

Ref country code: DE