WO2012060402A1 - All-solid-state battery and method for manufacturing same - Google Patents

All-solid-state battery and method for manufacturing same Download PDF

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Publication number
WO2012060402A1
WO2012060402A1 PCT/JP2011/075270 JP2011075270W WO2012060402A1 WO 2012060402 A1 WO2012060402 A1 WO 2012060402A1 JP 2011075270 W JP2011075270 W JP 2011075270W WO 2012060402 A1 WO2012060402 A1 WO 2012060402A1
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Prior art keywords
electrode layer
solid
solid electrolyte
negative electrode
layer
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PCT/JP2011/075270
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French (fr)
Japanese (ja)
Inventor
充 吉岡
倍太 尾内
剛司 林
邦雄 西田
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株式会社 村田製作所
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Publication of WO2012060402A1 publication Critical patent/WO2012060402A1/en

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    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • 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
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention generally relates to an all-solid battery and a method for manufacturing the same, and more specifically, includes a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, and a negative electrode layer, and at least one of a positive electrode layer or a negative electrode layer;
  • the present invention relates to an all-solid battery in which a solid electrolyte layer is bonded by firing and a method for manufacturing the same.
  • the battery having the above configuration has a risk of leakage of the electrolyte.
  • the organic solvent etc. which are used for electrolyte solution are combustible substances. For this reason, it is required to further increase the safety of the battery.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2007-258148 proposes an all-solid battery in which all components are made of solid using a nonflammable solid electrolyte.
  • this all solid state battery a stacked type solid state battery in which an electrode layer (positive electrode layer, negative electrode layer) and a solid electrolyte layer are joined by firing is described.
  • An electrode paste was prepared by mixing Li 3 V 2 (PO 4 ) 3 as an electrode active material with acetylene black as a conductive agent so as to be 25% by mass, and Li 1.5 Al 0.5 Ge 1.5 as a solid electrolyte layer. (PO 4 ) 3
  • Electrode paste is screen-printed on both surfaces of the sintered body, and then baked at a temperature of 700 ° C. to produce a solid battery laminate.
  • an object of the present invention is to have sufficient laminate strength even when an electrode material in which a carbon material is added as a conductive agent to an electrode active material is used and the electrode layer and the solid electrolyte layer are joined by integral firing.
  • An all-solid-state battery and a method for manufacturing the same are provided.
  • An all solid state battery comprises a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, and a negative electrode layer, wherein at least one of the positive electrode layer or the negative electrode layer and the solid electrolyte layer are joined by firing.
  • at least one of the positive electrode layer or the negative electrode layer includes an electrode active material and a conductive agent containing a carbon material, and the content of the carbon material contained in at least one starting material of the positive electrode layer or the negative electrode layer is It is 1 mass% or more and less than 25 mass%.
  • At least one of the solid electrolyte and the electrode active material contains a lithium-containing phosphate compound.
  • the solid electrolyte contains a lithium-containing phosphate compound having a NASICON type structure.
  • the manufacturing method of an all-solid battery according to the present invention is a manufacturing method of an all-solid battery having the above-described features, and includes the following steps.
  • At least one of the positive electrode layer or negative electrode layer slurry contains an electrode active material and a conductive agent containing a carbon material, and is contained in at least one of the positive electrode layer or negative electrode layer slurry.
  • the content of the carbon material is 1% by mass or more and less than 25% by mass.
  • the content of the carbon material contained in at least one of the positive electrode layer or the negative electrode layer slurry is based on the total amount of the inorganic material including the electrode active material, the solid electrolyte, the conductive agent, and other sintering aids. Refers to the mass ratio.
  • the electrode layer and the solid electrolyte layer are integrally fired. Can be obtained with good sinterability and sufficient strength of the laminate, and can impart electronic conductivity in the positive electrode layer or the negative electrode layer. Discharge characteristics can be obtained.
  • FIG. 1 is a perspective view schematically showing an all-solid battery as one embodiment of the present invention. It is a perspective view which shows typically an all-solid-state battery as another embodiment of this invention. It is sectional drawing which shows typically the cross-section of the laminated body which comprises the all-solid-state battery produced in Example 1 and 2 of this invention. It is sectional drawing which shows typically the cross-section of the laminated body which comprises the all-solid-state battery produced in Example 3 of this invention. It is a figure which shows the charging / discharging curve of the all-solid-state battery produced in Example 1 of this invention.
  • the all-solid battery stack 10 of the present invention includes a positive electrode layer 11, a solid electrolyte layer 13, and a negative electrode layer 12.
  • the all-solid battery stack 10 is formed in a rectangular parallelepiped shape, and is configured by a stack including a plurality of flat layers having a rectangular plane.
  • the all-solid-state battery stack 10 is formed in a cylindrical shape and is formed of a stack made of a plurality of disk-shaped layers.
  • Each of the positive electrode layer 11 and the negative electrode layer 12 includes an electrode active material, or includes a solid electrolyte and an electrode active material, and the solid electrolyte layer 13 includes a solid electrolyte. At least one of the positive electrode layer 11 or the negative electrode layer 12 includes a conductive agent including a carbon material.
  • the positive electrode layer 11 or the negative electrode layer 12 and the solid electrolyte layer 13 are joined by baking.
  • the content of the carbon material contained in at least one starting material of the positive electrode layer 11 or the negative electrode layer 12 is 1% by mass or more and less than 25% by mass.
  • the content of the carbon material contained in at least one starting material of the positive electrode layer 11 or the negative electrode layer 12 is 1% by mass or more and less than 25% by mass, the electrode layer (positive electrode layer 11 or negative electrode layer 12) and solid Even when the electrolyte layer 13 is joined by integral firing, the sinterability is good, sufficient strength of the laminate can be obtained, and electron conductivity is imparted in the positive electrode layer 11 or the negative electrode layer 12. As a result, good charge / discharge characteristics can be obtained.
  • the content of the carbon material is less than 1% by mass, sufficient electron conductivity in the electrode layer (positive electrode layer 11 or negative electrode layer 12) cannot be obtained, and charge / discharge characteristics are deteriorated.
  • the content of the carbon material is 25% by mass or more, the electrode active material and the solid electrolyte are not sufficiently sintered at the time of firing, and the strength of the all-solid battery stack 10 is weakened. Becomes easy to break.
  • the content of the carbon material is 1% by mass or more and less than 25% by mass, the electron conductivity in the electrode layer (positive electrode layer 11 or negative electrode layer 12) can be obtained, but the content of the carbon material is preferably 5% by mass. It is 20 mass% or less.
  • the utilization factor of the electrode active material can be improved, the density of the electrode layer can be increased, and the energy volume density can be increased.
  • the carbon material content is 10% by mass or more and 20% by mass or less. In this case, the above effect can be further improved.
  • Carbon powder such as acetylene black, ketjen black, and furnace black, is used as a carbon material.
  • the type of the electrode active material is not limited.
  • the positive electrode active material include lithium-containing phosphate compounds having a NASICON structure such as Li 3 V 2 (PO 4 ) 3 , olivine such as LiFePO 4 and LiMnPO 4.
  • Type lithium-containing phosphate compound, layered compound such as LiCoO 2 , LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiMn 2 O 4 , LiNi 0.5 Mn 1.5 O 4 , Li 4 Ti 5 O 12
  • a lithium-containing compound having a spinel structure such as can be used.
  • MOx (M is at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, and Mo, and x is in the range of 0.9 ⁇ x ⁇ 2.0.
  • a compound having a composition represented by the following numerical value can be used.
  • a mixture in which two or more active materials having a composition represented by MOx containing different elements M such as TiO 2 and SiO 2 may be used.
  • graphite-lithium compounds, lithium alloys such as Li-Al, oxidations such as Li 3 V 2 (PO 4 ) 3 , Li 3 Fe 2 (PO 4 ) 3 , Li 4 Ti 5 O 12 Can be used.
  • a lithium-containing phosphate compound having a NASICON structure can be used as the solid electrolyte.
  • Lithium-containing phosphoric acid compound having a NASICON-type structure the chemical formula Li x M y (PO 4) 3 ( Formula, x 1 ⁇ x ⁇ 2, y is a number in the range of 1 ⁇ y ⁇ 2, M Is one or more elements selected from the group consisting of Ti, Ge, Al, Ga and Zr).
  • part of P in the above chemical formula may be substituted with B, Si, or the like.
  • a compound having two or more different compositions of a lithium-containing phosphate compound having a NASICON structure such as Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 and Li 1.2 Al 0.2 Ti 1.8 (PO 4 ) 3 is mixed. You may use the mixture.
  • the lithium-containing phosphate compound having a NASICON structure used in the solid electrolyte is a compound containing a crystal phase of a lithium-containing phosphate compound having a NASICON structure or a lithium-containing phosphate having a NASICON structure by heat treatment. You may use the glass which precipitates the crystal phase of a phosphoric acid compound.
  • a material used for said solid electrolyte it is possible to use the material which has ion conductivity and is so small that electronic conductivity can be disregarded other than the lithium-containing phosphate compound which has a NASICON structure.
  • examples of such a material include lithium halide, lithium nitride, lithium oxyacid salt, and derivatives thereof.
  • Li—PO compounds such as lithium phosphate (Li 3 PO 4 ), LIPON (LiPO 4 ⁇ x N x ) in which nitrogen is mixed with lithium phosphate, and Li—Si—O such as Li 4 SiO 4
  • Li—Si—O such as Li 4 SiO 4
  • Examples thereof include a compound having a lobskite structure, a compound having a garnet structure having Li, La, and Zr.
  • At least one of the solid electrolyte or the electrode active material includes a lithium-containing phosphate compound. Moreover, it is preferable that said solid electrolyte contains the lithium containing phosphoric acid compound of NASICON type
  • the solid electrolyte and the electrode active material include a lithium-containing phosphate compound such as a lithium-containing phosphate compound having a NASICON structure and a lithium-containing phosphate compound having an olivine structure.
  • a lithium-containing phosphate compound such as a lithium-containing phosphate compound having a NASICON structure
  • a lithium-containing phosphate compound having an olivine structure such as a lithium-containing phosphate compound having an olivine structure.
  • a molded body of a positive electrode material including a solid electrolyte and an electrode active material is produced.
  • a molded body of a negative electrode material including a solid electrolyte and an electrode active material is produced.
  • a compact of a solid electrolyte material is produced.
  • each of the molded bodies can be produced in the form of a green sheet.
  • each molded object is laminated
  • the all-solid battery laminate 10 composed of the laminate of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 can be formed by integral firing.
  • the firing temperature is preferably 500 ° C. or higher and 700 ° C. or lower.
  • each slurry of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 is prepared (slurry preparation step). Thereafter, each of the slurry of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 is formed to produce a green sheet (green sheet forming step). And the green body of each of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 is laminated
  • At least one of the slurry of the positive electrode layer 11 or the negative electrode layer 12 includes an electrode active material and a conductive agent including a carbon material, and the positive electrode layer 11 or the negative electrode layer 12.
  • the content of the carbon material contained in at least one of the slurries is 1% by mass or more and less than 25% by mass.
  • the method for forming the green sheet is not particularly limited, but a die coater, a comma coater, screen printing, or the like can be used.
  • the method of laminating the green sheets is not particularly limited, but the green sheets can be laminated using a hot isostatic press (HIP), a cold isostatic press (CIP), a hydrostatic press (WIP), or the like. it can.
  • the atmosphere for firing the laminate of green sheets is not particularly limited, but it is preferably performed under conditions that do not change the valence of the transition metal contained in the electrode active material.
  • At least one of the positive electrode layer 11 or the negative electrode layer 12 and the solid electrolyte layer 13 are joined by integral firing.
  • Example shown below is an example and this invention is not limited to the following Example.
  • MoO 2 Molybdenum dioxide
  • LAGP Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3
  • AB acetylene black
  • the glass powder of LAGP as a solid electrolyte material and polyvinyl alcohol as a binder were mixed to prepare a solid electrolyte slurry 1.
  • a conductive agent slurry 1 was prepared by mixing AB as a conductive agent and polyvinyl alcohol as a binder.
  • electrode slurry 1 was prepared.
  • the electrode slurry 1 and the solid electrolyte green sheet 1 produced as described above were formed into a thickness of 50 ⁇ m using a doctor blade to produce an electrode green sheet 1 and a solid electrolyte green sheet 1.
  • a green sheet for the negative electrode layer 12 (electrode green sheet 1) punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. ) Is laminated in the configuration of the laminate as shown in FIG. 4 and thermocompression bonded at a temperature of 80 ° C. with a pressure of 1 ton to form a laminate constituting a part of the all-solid battery laminate 110. A green sheet laminate 1 was produced.
  • the green sheet laminate 1 is sandwiched between two alumina ceramic plates, baked in air at a temperature of 500 ° C., and after removing polyvinyl alcohol, the glass sheet laminate is heated to 600 ° C. in a nitrogen gas atmosphere. As shown in FIG. 4, the negative electrode layer 12 and the solid electrolyte layer 13 were joined by integral firing to produce a laminate 1 constituting a part of the all-solid battery laminate 110.
  • the obtained laminate 1 was dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 4, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as positive electrode layer 11 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131.
  • PMMA polymethyl methacrylate
  • the positive electrode layer 11 was laminated to the all-solid battery laminate 110.
  • the all solid state battery stack 110 was sealed with a 2032 type coin cell to produce the all solid state battery 1.
  • FIG. 6 shows a charge / discharge curve of the all-solid battery 1.
  • a decrease in potential due to lithium insertion into MoO 2 used as the negative electrode active material is defined as charging, and a rise in potential due to lithium desorption from MoO 2 is defined as discharging.
  • the horizontal axis of FIG. 6 shows the capacity [mAh / g] per gram with respect to the mass of molybdenum dioxide contained in the negative electrode layer.
  • an all-solid battery using an electrode sheet not containing a conductive agent was prepared and evaluated.
  • Electrode green sheet 1a was produced by forming electrode slurry 1a produced as described above to a thickness of 50 ⁇ m using a doctor blade.
  • a green sheet for the negative electrode layer 12 (electrode green sheet 1a) punched into a disk shape with a diameter of 12 mm is formed on one surface of a green sheet for solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. ) Is laminated in the configuration of the laminate as shown in FIG. 4 and thermocompression bonded at a temperature of 80 ° C. with a pressure of 1 ton to form a laminate constituting a part of the all-solid battery laminate 110. A green sheet laminate 1a was produced.
  • the green sheet laminate 1a is sandwiched between two alumina ceramic plates, fired in air at a temperature of 500 ° C., and after removal of polyvinyl alcohol, the temperature is 600 ° C. in a nitrogen gas atmosphere. As shown in FIG. 4, the negative electrode layer 12 and the solid electrolyte layer 13 were joined by integral firing to produce a laminate 1 a constituting a part of the all-solid battery laminate 110.
  • the obtained laminate 1a was dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 4, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as positive electrode layer 11 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131.
  • PMMA polymethyl methacrylate
  • the positive electrode layer 11 was laminated to the all-solid battery laminate 110.
  • the all-solid battery stack 110 was sealed with a 2032 type coin cell to produce an all-solid battery 1a.
  • the all-solid-state battery 1a was subjected to constant current constant voltage charge / discharge measurement at a voltage range of 1.4 to 3 V and a current density of 100 ⁇ A / cm 2 . As a result, it was confirmed that charging / discharging was performed at an initial discharge capacity per unit mass of the electrode active material (MoO 2 ) of about 50 mAh / g.
  • Example 1 Although only what used acetylene black (AB) as a carbon powder was demonstrated, carbon powder is not restricted to AB, Carbon powder, such as Ketjen black and furnace black, is used. Even if it is used, the same effect can be obtained.
  • AB acetylene black
  • the sealing method of an all-solid-state battery laminated body is not specifically limited, You may seal the sintered laminated body with resin. An insulating paste such as Al 2 O 3 may be applied or dipped around the laminated body and heat-treated to seal it. In order to draw current efficiently from the positive and negative electrode layers, a conductive layer such as a metal layer may be formed on the positive and negative electrode layers by sputtering or the like. A conductive layer may be formed by applying or dipping a metal paste or the like on the positive and negative electrode layers and heat-treating it.
  • Anatase type titanium oxide (hereinafter referred to as TiO 2 ) was used as an electrode active material, glass powder LAGP having a composition of a lithium-containing phosphate compound having a NASICON type structure as a solid electrolyte, and AB was used as a conductive agent.
  • Electrode active material slurry 2 The electrode active material slurry 2, the solid electrolyte slurry 1 and the conductive agent slurry 1 prepared above were mixed so that the mixing ratio of TiO 2 , LAGP and AB was a mass ratio and the value shown in Table 1. Electrode slurries 2 to 8 were prepared.
  • Electrode green sheets 2 to 8 were produced by forming the electrode slurries 2 to 8 produced as described above to a thickness of 50 ⁇ m using a doctor blade.
  • a green sheet for the negative electrode layer 12 (electrode green sheet 2) punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm.
  • To 8 are laminated in the structure of the laminated body as shown in FIG. 4 and thermocompression bonded at a temperature of 80 ° C. with a pressure of 1 ton to form a laminated body constituting a part of the all-solid-state battery laminated body 110.
  • Green sheet laminates 2 to 8 for formation were produced.
  • Each of the green sheet laminates 2 to 8 is sandwiched between two alumina ceramic plates, fired in air at a temperature of 500 ° C. to remove polyvinyl alcohol, and then placed in a nitrogen gas atmosphere. As shown in FIG. 4, the negative electrode layer 12 and the solid electrolyte layer 13 are joined by integral firing, so that the laminates 2 to 8 constituting a part of the all-solid battery 110 are fired at a temperature of 600 ° C. Was made.
  • the obtained laminates 2 to 8 were dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 4, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as positive electrode layer 11 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131.
  • PMMA polymethyl methacrylate
  • the positive electrode layer 11 was laminated to the all-solid battery laminate 110.
  • the all solid state battery stack 110 was sealed with a 2032 type coin cell to prepare all solid state batteries 2 to 8.
  • the laminates 7 and 8 have insufficient sintering of the electrode active material and the solid electrolyte, and the strengths of the laminates 2 to 6 are the same as those of the other laminates 2 to 6. Compared to this, the laminate 8 was easily broken during handling.
  • the all-solid-state batteries 2 to 8 were subjected to constant current and constant voltage charge / discharge measurement in a voltage range of 1.4 to 3 V and a current density of 100 ⁇ A / cm 2 .
  • Table 2 shows the measurement results of the discharge capacity per unit mass of the electrode active material (TiO 2 ) for all solid state batteries 2 to 8 (laminates 2 to 8).
  • the negative electrode layer 12 has the highest electronic conductivity and the highest discharge capacity.
  • the laminates 7 and 8 have insufficient sintering of the electrode active material and the solid electrolyte, and the strength thereof is lower than those of the other laminates 2 to 6, so that an all-solid battery is formed. It was not suitable for use.
  • the discharge capacity decreased as the carbon content decreased.
  • Inorganic crystal powder Li 3 V 2 (PO 4 ) 3 (hereinafter referred to as LVP) having a composition of a lithium-containing phosphate compound having a NASICON structure as an electrode active material, and a composition of a lithium-containing phosphate compound having a NASICON structure as a solid electrolyte
  • LVP Inorganic crystal powder Li 3 V 2 (PO 4 ) 3
  • furnace black was added as a carbon powder during synthesis.
  • An electrode active material slurry 9 was prepared by mixing LVP crystal powder as an electrode active material in a binder solution obtained by dissolving polyvinyl alcohol as a binder in toluene.
  • the electrode active material slurry 9 and the solid electrolyte slurry 1 produced above were mixed so that the mixing ratio of LVP, LAGP, and furnace black was 35:50:15, and the electrode slurry 9 was Produced.
  • the electrode slurry 9 produced as described above was formed into a thickness of 50 ⁇ m by using a doctor blade to produce an electrode green sheet 9.
  • a green sheet for the positive electrode layer 11 (electrode green sheet 9) punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. )
  • electrode green sheet 9 punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm.
  • the green sheet laminate 9 is sandwiched between two alumina ceramic plates, fired in air at a temperature of 500 ° C., and after removing polyvinyl alcohol, the glass sheet laminate 9 is heated to 600 ° C. in a nitrogen gas atmosphere. As shown in FIG. 5, the positive electrode layer 11 and the solid electrolyte layer 13 were joined by integral firing to produce a laminate 9 constituting a part of the all-solid battery laminate 120.
  • the obtained laminate 9 was dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 5, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as negative electrode layer 12 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131. A negative electrode layer 12 was laminated to the all-solid battery laminate 120. The all solid state battery laminate 120 was sealed with a 2032 type coin cell to produce the all solid state battery 9.
  • PMMA polymethyl methacrylate
  • the all-solid-state battery 9 was subjected to constant current constant voltage charge / discharge measurement in a voltage range of 3.0 to 4.5 V and a current density of 100 ⁇ A / cm 2 . As a result, it was confirmed that charging / discharging was possible at a discharge capacity per unit mass of the electrode active material (LVP) of about 110 mAh / g, indicating a high discharge capacity.
  • LVP electrode active material

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Abstract

Provided is an all-solid-state battery that uses an electrode material in which a carbon material is added as a conductor to an electrode active material and that has sufficient laminate strength even if an electrode layer and solid electrolyte layer are joined by integral sintering. Also provided is a method for manufacturing the same. An all-solid-state battery laminate (10) comprises a positive electrode layer (11), a solid electrolyte layer (13) that contains a solid electrolyte, and a negative electrode layer (12). Either or both of the positive electrode layer (11) and negative electrode layer (12) are joined to the solid electrolyte layer (13) by sintering. Either or both of the positive electrode layer (11) and the negative electrode layer (12) contain an electrode active material and a conductor that contains a carbon material, and the carbon material content in a starting material for either or both of the positive electrode layer (11) and the negative electrode layer (12) is 1% by mass to less than 25% by mass.

Description

全固体電池およびその製造方法All-solid battery and method for manufacturing the same
　本発明は、一般的には全固体電池およびその製造方法に関し、特定的には、正極層と、固体電解質を含む固体電解質層と、負極層とを備え、正極層または負極層の少なくとも一方と固体電解質層とが焼成によって接合された全固体電池およびその製造方法に関する。 The present invention generally relates to an all-solid battery and a method for manufacturing the same, and more specifically, includes a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, and a negative electrode layer, and at least one of a positive electrode layer or a negative electrode layer; The present invention relates to an all-solid battery in which a solid electrolyte layer is bonded by firing and a method for manufacturing the same.
　近年、携帯電話、携帯用パーソナルコンピュータなどの携帯用電子機器の電源として電池の需要が大幅に拡大している。このような用途に用いられる電池においては、イオンを移動させるための媒体として有機溶媒などの電解質（電解液）が従来から使用されている。 In recent years, the demand for batteries as a power source for portable electronic devices such as mobile phones and portable personal computers has greatly increased. In a battery used for such an application, an electrolyte (electrolytic solution) such as an organic solvent has been conventionally used as a medium for moving ions.
　しかし、上記の構成の電池では、電解液が漏出するという危険性がある。また、電解液に用いられる有機溶媒などは可燃性物質である。このため、電池の安全性をさらに高めることが求められている。 However, the battery having the above configuration has a risk of leakage of the electrolyte. Moreover, the organic solvent etc. which are used for electrolyte solution are combustible substances. For this reason, it is required to further increase the safety of the battery.
　そこで、電池の安全性を高めるための一つの対策は、電解質として、電解液に代えて、固体電解質を用いることが提案されている。さらに、電解質として固体電解質を用いるとともに、その他の構成要素も固体で構成されている全固体電池の開発が進められている。 Therefore, as one countermeasure for improving the safety of the battery, it has been proposed to use a solid electrolyte as the electrolyte instead of the electrolytic solution. Furthermore, development of an all-solid battery in which a solid electrolyte is used as an electrolyte and the other constituent elements are also made of solid is being promoted.
　たとえば、特開２００７－２５８１４８号公報（以下、特許文献１という）には、不燃性の固体電解質を用いてすべての構成要素を固体で構成した全固体電池が提案されている。この全固体電池の実施例として、電極層（正極層、負極層）と固体電解質層とが焼成によって接合された積層型固体電池が記載されている。電極活物質としてのＬｉ3Ｖ2（ＰＯ4）3に、導電剤としてのアセチレンブラックを２５質量％となるように混合して電極ペーストを作製し、固体電解質層としてのＬｉ1.5Ａｌ0.5Ｇｅ1.5（ＰＯ4）3焼結体の両面に電極ペーストをスクリーン印刷した後、７００℃の温度で焼き付けて固体電池用積層体を作製している。 For example, Japanese Patent Application Laid-Open No. 2007-258148 (hereinafter referred to as Patent Document 1) proposes an all-solid battery in which all components are made of solid using a nonflammable solid electrolyte. As an example of this all solid state battery, a stacked type solid state battery in which an electrode layer (positive electrode layer, negative electrode layer) and a solid electrolyte layer are joined by firing is described. An electrode paste was prepared by mixing Li 3 V 2 (PO 4 ) 3 as an electrode active material with acetylene black as a conductive agent so as to be 25% by mass, and Li 1.5 Al 0.5 Ge 1.5 as a solid electrolyte layer. (PO 4 ) 3 Electrode paste is screen-printed on both surfaces of the sintered body, and then baked at a temperature of 700 ° C. to produce a solid battery laminate.
特開２００７－２５８１４８号公報JP 2007-258148 A
　しかしながら、電極活物質に導電剤としてのアセチレンブラックを２５質量％添加して電極スラリーを作製して、電極スラリーと固体電解質スラリーとを一体焼成によって接合して固体電池用積層体を作製すると、焼結性が良好でなく、積層体の強度が低下することがわかった。このような発明者らの知見に基づいて本発明はなされたものである。 However, when an electrode slurry is prepared by adding 25% by mass of acetylene black as a conductive agent to the electrode active material, and the electrode slurry and the solid electrolyte slurry are joined by integral firing, a laminate for a solid battery is produced. It was found that the caking property was not good and the strength of the laminate was lowered. The present invention has been made based on such knowledge of the inventors.
　したがって、本発明の目的は、電極活物質に導電剤として炭素材料を添加した電極材料を使用し、電極層と固体電解質層とを一体焼成によって接合しても、十分な積層体の強度を有する全固体電池およびその製造方法を提供することである。 Therefore, an object of the present invention is to have sufficient laminate strength even when an electrode material in which a carbon material is added as a conductive agent to an electrode active material is used and the electrode layer and the solid electrolyte layer are joined by integral firing. An all-solid-state battery and a method for manufacturing the same are provided.
　本発明に従った全固体電池は、正極層と、固体電解質を含む固体電解質層と、負極層とを備え、正極層または負極層の少なくとも一方と固体電解質層とが焼成によって接合された全固体電池であって、正極層または負極層の少なくとも一方が、電極活物質と、炭素材料を含む導電剤とを含み、正極層または負極層の少なくとも一方の出発材料に含まれる炭素材料の含有量が１質量％以上２５質量％未満である。 An all solid state battery according to the present invention comprises a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, and a negative electrode layer, wherein at least one of the positive electrode layer or the negative electrode layer and the solid electrolyte layer are joined by firing. In the battery, at least one of the positive electrode layer or the negative electrode layer includes an electrode active material and a conductive agent containing a carbon material, and the content of the carbon material contained in at least one starting material of the positive electrode layer or the negative electrode layer is It is 1 mass% or more and less than 25 mass%.
　本発明の全固体電池において、固体電解質または電極活物質の少なくとも一方が、リチウム含有リン酸化合物を含むことが好ましい。 In the all solid state battery of the present invention, it is preferable that at least one of the solid electrolyte and the electrode active material contains a lithium-containing phosphate compound.
　また、本発明の全固体電池において、固体電解質が、ナシコン型構造のリチウム含有リン酸化合物を含むことが好ましい。 In the all solid state battery of the present invention, it is preferable that the solid electrolyte contains a lithium-containing phosphate compound having a NASICON type structure.
　本発明に従って全固体電池の製造方法は、上述の特徴を備えた全固体電池の製造方法であって、以下の工程を備える。 The manufacturing method of an all-solid battery according to the present invention is a manufacturing method of an all-solid battery having the above-described features, and includes the following steps.
　（Ａ）正極層、固体電解質層、および、負極層の各々のスラリーを調製するスラリー調製工程 (A) Slurry preparation step of preparing each slurry of positive electrode layer, solid electrolyte layer, and negative electrode layer
　（Ｂ）正極層、固体電解質層、および、負極層の各々のスラリーを成形してグリーンシートを作製するグリーンシート成形工程 (B) Green sheet forming step of forming a green sheet by forming each slurry of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer
　（Ｃ）正極層、固体電解質層、および、負極層の各々のグリーンシートを積層して積層体を形成する積層体形成工程 (C) Laminate forming step of forming a laminate by laminating the green sheets of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer
　（Ｄ）積層体を焼成する焼成工程 (D) Firing step of firing the laminate
　（Ｅ）スラリー調製工程において、正極層または負極層のスラリーの少なくとも一方が、電極活物質と、炭素材料を含む導電剤とを含み、かつ、正極層または負極層のスラリーの少なくとも一方に含まれる炭素材料の含有量が１質量％以上２５質量％未満である。ここで、正極層または負極層のスラリーの少なくとも一方に含まれる炭素材料の含有量とは、電極活物質、固体電解質、導電剤、および、その他の焼結助剤などを含む無機材料の総量に対する質量比率をいう。 (E) In the slurry preparation step, at least one of the positive electrode layer or negative electrode layer slurry contains an electrode active material and a conductive agent containing a carbon material, and is contained in at least one of the positive electrode layer or negative electrode layer slurry. The content of the carbon material is 1% by mass or more and less than 25% by mass. Here, the content of the carbon material contained in at least one of the positive electrode layer or the negative electrode layer slurry is based on the total amount of the inorganic material including the electrode active material, the solid electrolyte, the conductive agent, and other sintering aids. Refers to the mass ratio.
　本発明の全固体電池では、正極層または負極層の少なくとも一方の出発材料に含まれる炭素材料の含有量が１質量％以上２５質量％未満であるので、電極層と固体電解質層とを一体焼成によって接合しても、焼結性が良好で、十分な積層体の強度を得ることができるとともに、正極層内または負極層内に電子伝導性を付与することができ、その結果、良好な充放電特性を得ることができる。 In the all solid state battery of the present invention, since the content of the carbon material contained in at least one starting material of the positive electrode layer or the negative electrode layer is 1% by mass or more and less than 25% by mass, the electrode layer and the solid electrolyte layer are integrally fired. Can be obtained with good sinterability and sufficient strength of the laminate, and can impart electronic conductivity in the positive electrode layer or the negative electrode layer. Discharge characteristics can be obtained.
本発明の実施形態として全固体電池の断面構造を模式的に示す断面図である。It is sectional drawing which shows typically the cross-section of an all-solid-state battery as embodiment of this invention. 本発明の一つの実施形態として全固体電池を模式的に示す斜視図である。1 is a perspective view schematically showing an all-solid battery as one embodiment of the present invention. 本発明のもう一つの実施形態として全固体電池を模式的に示す斜視図である。It is a perspective view which shows typically an all-solid-state battery as another embodiment of this invention. 本発明の実施例１と２で作製された全固体電池を構成する積層体の断面構造を模式的に示す断面図である。It is sectional drawing which shows typically the cross-section of the laminated body which comprises the all-solid-state battery produced in Example 1 and 2 of this invention. 本発明の実施例３で作製された全固体電池を構成する積層体の断面構造を模式的に示す断面図である。It is sectional drawing which shows typically the cross-section of the laminated body which comprises the all-solid-state battery produced in Example 3 of this invention. 本発明の実施例１で作製された全固体電池の充放電曲線を示す図である。It is a figure which shows the charging / discharging curve of the all-solid-state battery produced in Example 1 of this invention.
　図１に示すように、本発明の全固体電池積層体１０は、正極層１１と固体電解質層１３と負極層１２とを備える。図２に示すように本発明の一つの実施形態として全固体電池積層体１０は直方体形状に形成され、矩形の平面を有する複数の平板状層からなる積層体で構成される。また、図３に示すように本発明のもう一つの実施形態として全固体電池積層体１０は円柱形状に形成され、複数の円板状層からなる積層体で構成される。なお、正極層１１と負極層１２のそれぞれは、電極活物質を含み、または、固体電解質と電極活物質とを含み、固体電解質層１３は固体電解質を含む。正極層１１または負極層１２の少なくとも一方が、炭素材料を含む導電剤を含む。 As shown in FIG. 1, the all-solid battery stack 10 of the present invention includes a positive electrode layer 11, a solid electrolyte layer 13, and a negative electrode layer 12. As shown in FIG. 2, as one embodiment of the present invention, the all-solid battery stack 10 is formed in a rectangular parallelepiped shape, and is configured by a stack including a plurality of flat layers having a rectangular plane. As shown in FIG. 3, as another embodiment of the present invention, the all-solid-state battery stack 10 is formed in a cylindrical shape and is formed of a stack made of a plurality of disk-shaped layers. Each of the positive electrode layer 11 and the negative electrode layer 12 includes an electrode active material, or includes a solid electrolyte and an electrode active material, and the solid electrolyte layer 13 includes a solid electrolyte. At least one of the positive electrode layer 11 or the negative electrode layer 12 includes a conductive agent including a carbon material.
　上記のように構成された全固体電池積層体１０では、正極層１１または負極層１２の少なくとも一方と固体電解質層１３とが焼成によって接合されている。正極層１１または負極層１２の少なくとも一方の出発材料に含まれる炭素材料の含有量が１質量％以上２５質量％未満である。 In the all-solid battery stack 10 configured as described above, at least one of the positive electrode layer 11 or the negative electrode layer 12 and the solid electrolyte layer 13 are joined by baking. The content of the carbon material contained in at least one starting material of the positive electrode layer 11 or the negative electrode layer 12 is 1% by mass or more and less than 25% by mass.
　このように正極層１１または負極層１２の少なくとも一方の出発材料に含まれる炭素材料の含有量が１質量％以上２５質量％未満であるので、電極層（正極層１１または負極層１２）と固体電解質層１３とを一体焼成によって接合しても、焼結性が良好で、十分な積層体の強度を得ることができるとともに、正極層１１内または負極層１２内に電子伝導性を付与することができ、その結果、良好な充放電特性を得ることができる。炭素材料の含有量が１質量％未満の場合には、電極層（正極層１１または負極層１２）内の電子伝導性が十分に得られず、充放電特性が低下する。炭素材料の含有量が２５質量％以上の場合には、焼成時に電極活物質と固体電解質の焼結が不十分になり、全固体電池積層体１０の強度が弱くなり、全固体電池積層体１０が割れやすくなる。 Thus, since the content of the carbon material contained in at least one starting material of the positive electrode layer 11 or the negative electrode layer 12 is 1% by mass or more and less than 25% by mass, the electrode layer (positive electrode layer 11 or negative electrode layer 12) and solid Even when the electrolyte layer 13 is joined by integral firing, the sinterability is good, sufficient strength of the laminate can be obtained, and electron conductivity is imparted in the positive electrode layer 11 or the negative electrode layer 12. As a result, good charge / discharge characteristics can be obtained. When the content of the carbon material is less than 1% by mass, sufficient electron conductivity in the electrode layer (positive electrode layer 11 or negative electrode layer 12) cannot be obtained, and charge / discharge characteristics are deteriorated. When the content of the carbon material is 25% by mass or more, the electrode active material and the solid electrolyte are not sufficiently sintered at the time of firing, and the strength of the all-solid battery stack 10 is weakened. Becomes easy to break.
　炭素材料の含有量が１質量％以上２５質量％未満であれば、電極層（正極層１１または負極層１２）内の電子伝導性が得られるが、好ましくは炭素材料の含有量が５質量％以上２０質量％以下である。この場合、電極活物質の利用率を向上させ、電極層の密度が高くなり、エネルギー体積密度を高めることができる。また、さらに好ましくは炭素材料の含有量が１０質量％以上２０質量％以下である。この場合、上記の効果をさらに向上させることができる。 If the content of the carbon material is 1% by mass or more and less than 25% by mass, the electron conductivity in the electrode layer (positive electrode layer 11 or negative electrode layer 12) can be obtained, but the content of the carbon material is preferably 5% by mass. It is 20 mass% or less. In this case, the utilization factor of the electrode active material can be improved, the density of the electrode layer can be increased, and the energy volume density can be increased. More preferably, the carbon material content is 10% by mass or more and 20% by mass or less. In this case, the above effect can be further improved.
　なお、上記の導電剤に含められる炭素材料の種類は特に限定されないが、アセチレンブラック、ケッチェンブラック、ファーネスブラックなどの炭素粉末が炭素材料として用いられる。 In addition, although the kind of carbon material included in said electrically conductive agent is not specifically limited, Carbon powder, such as acetylene black, ketjen black, and furnace black, is used as a carbon material.
　また、上記の電極活物質の種類は限定されないが、正極活物質としては、Ｌｉ3Ｖ2（ＰＯ4）3などのナシコン型構造を有するリチウム含有リン酸化合物、ＬｉＦｅＰＯ4、ＬｉＭｎＰＯ4などのオリビン型構造を有するリチウム含有リン酸化合物、ＬｉＣｏＯ2、ＬｉＣｏ1/3Ｎｉ1/3Ｍｎ1/3Ｏ2などの層状化合物、ＬｉＭｎ2Ｏ4、ＬｉＮｉ0.5Ｍｎ1.5Ｏ4、Ｌｉ4Ｔｉ5Ｏ12などのスピネル型構造を有するリチウム含有化合物を用いることができる。 The type of the electrode active material is not limited. Examples of the positive electrode active material include lithium-containing phosphate compounds having a NASICON structure such as Li 3 V 2 (PO 4 ) 3 , olivine such as LiFePO 4 and LiMnPO 4. Type lithium-containing phosphate compound, layered compound such as LiCoO 2 , LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiMn 2 O 4 , LiNi 0.5 Mn 1.5 O 4 , Li 4 Ti 5 O 12 A lithium-containing compound having a spinel structure such as can be used.
　負極活物質としては、ＭＯｘ（ＭはＴｉ、Ｓｉ、Ｓｎ、Ｃｒ、ＦｅおよびＭｏからなる群より選ばれた少なくとも１種以上の元素であり、ｘは０．９≦ｘ≦２．０の範囲内の数値である)で表わされる組成を有する化合物を用いることができる。たとえば、ＴｉＯ2とＳｉＯ2、などの異なる元素Ｍを含むＭＯｘで表わされる組成を有する２つ以上の活物質を混合した混合物を用いてもよい。また、負極活物質としては、黒鉛-リチウム化合物、Ｌｉ‐Ａｌなどのリチウム合金、Ｌｉ3Ｖ2（ＰＯ4）3、Ｌｉ3Ｆｅ2（ＰＯ4）3、Ｌｉ4Ｔｉ5Ｏ12などの酸化物、などを用いることができる。 As the negative electrode active material, MOx (M is at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, and Mo, and x is in the range of 0.9 ≦ x ≦ 2.0. A compound having a composition represented by the following numerical value can be used. For example, a mixture in which two or more active materials having a composition represented by MOx containing different elements M such as TiO 2 and SiO 2 may be used. As the negative electrode active material, graphite-lithium compounds, lithium alloys such as Li-Al, oxidations such as Li 3 V 2 (PO 4 ) 3 , Li 3 Fe 2 (PO 4 ) 3 , Li 4 Ti 5 O 12 Can be used.
　上記の固体電解質としては、ナシコン型構造を有するリチウム含有リン酸化合物を用いることができる。ナシコン型構造を有するリチウム含有リン酸化合物は、化学式ＬｉxＭy（ＰＯ4）3（化学式中、ｘは１≦ｘ≦２、ｙは１≦ｙ≦２の範囲内の数値であり、ＭはＴｉ、Ｇｅ、Ａｌ、ＧａおよびＺｒからなる群より選ばれた１種以上の元素である）で表わされる。この場合、上記化学式においてＰの一部をＢ、Ｓｉ等で置換してもよい。また、Ｌｉ1.5Ａｌ0.5Ｇｅ1.5（ＰＯ4）3とＬｉ1.2Ａｌ0.2Ｔｉ1.8（ＰＯ4）3などの、ナシコン型構造を有するリチウム含有リン酸化合物の２つ以上の異なる組成を有する化合物を混合した混合物を用いてもよい。 As the solid electrolyte, a lithium-containing phosphate compound having a NASICON structure can be used. Lithium-containing phosphoric acid compound having a NASICON-type structure, the chemical formula Li x M y (PO 4) 3 ( Formula, x 1 ≦ x ≦ 2, y is a number in the range of 1 ≦ y ≦ 2, M Is one or more elements selected from the group consisting of Ti, Ge, Al, Ga and Zr). In this case, part of P in the above chemical formula may be substituted with B, Si, or the like. Also, a compound having two or more different compositions of a lithium-containing phosphate compound having a NASICON structure such as Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 and Li 1.2 Al 0.2 Ti 1.8 (PO 4 ) 3 is mixed. You may use the mixture.
　また、上記の固体電解質に用いられるナシコン型構造を有するリチウム含有リン酸化合物としては、ナシコン型構造を有するリチウム含有リン酸化合物の結晶相を含む化合物、または、熱処理によりナシコン型構造を有するリチウム含有リン酸化合物の結晶相を析出するガラスを用いてもよい。 The lithium-containing phosphate compound having a NASICON structure used in the solid electrolyte is a compound containing a crystal phase of a lithium-containing phosphate compound having a NASICON structure or a lithium-containing phosphate having a NASICON structure by heat treatment. You may use the glass which precipitates the crystal phase of a phosphoric acid compound.
　なお、上記の固体電解質に用いられる材料としては、ナシコン型構造を有するリチウム含有リン酸化合物以外に、イオン伝導性を有し、電子伝導性が無視できるほど小さい材料を用いることが可能である。このような材料として、たとえば、ハロゲン化リチウム、窒化リチウム、リチウム酸素酸塩、および、これらの誘導体を挙げることができる。また、リン酸リチウム（Ｌｉ3ＰＯ4）などのＬｉ‐Ｐ‐Ｏ系化合物、リン酸リチウムに窒素を混ぜたＬＩＰＯＮ（ＬｉＰＯ4-xＮx）、Ｌｉ4ＳｉＯ4などのＬｉ‐Ｓｉ‐Ｏ系化合物、Ｌｉ‐Ｐ‐Ｓｉ‐Ｏ系化合物、Ｌｉ‐Ｖ‐Ｓｉ‐Ｏ系化合物、Ｌａ0.51Ｌｉ0.35ＴｉＯ2.94、Ｌａ0.55Ｌｉ0.35ＴｉＯ3、Ｌｉ3xＬａ2/3-xＴｉＯ3などのぺロブスカイト型構造を有する化合物、Ｌｉ、Ｌａ、Ｚｒを有するガーネット型構造を有する化合物、などを挙げることができる。 In addition, as a material used for said solid electrolyte, it is possible to use the material which has ion conductivity and is so small that electronic conductivity can be disregarded other than the lithium-containing phosphate compound which has a NASICON structure. Examples of such a material include lithium halide, lithium nitride, lithium oxyacid salt, and derivatives thereof. In addition, Li—PO compounds such as lithium phosphate (Li 3 PO 4 ), LIPON (LiPO 4−x N x ) in which nitrogen is mixed with lithium phosphate, and Li—Si—O such as Li 4 SiO 4 Compounds such as La-based compounds, Li-P-Si-O based compounds, Li-V-Si-O based compounds, La 0.51 Li 0.35 TiO 2.94 , La 0.55 Li 0.35 TiO 3 , Li 3x La 2 / 3-x TiO 3 Examples thereof include a compound having a lobskite structure, a compound having a garnet structure having Li, La, and Zr.
　上記の固体電解質または電極活物質の少なくとも一方が、リチウム含有リン酸化合物を含むことが好ましい。また、上記の固体電解質がナシコン型構造のリチウム含有リン酸化合物を含むことが好ましい。 It is preferable that at least one of the solid electrolyte or the electrode active material includes a lithium-containing phosphate compound. Moreover, it is preferable that said solid electrolyte contains the lithium containing phosphoric acid compound of NASICON type | mold structure.
　本発明の全固体電池の好ましい一つの実施形態では、固体電解質と電極活物質が、ナシコン構造を有するリチウム含有リン酸化合物、オリビン構造を有するリチウム含有リン酸化合物などのリチウム含有リン酸化合物を含む。このように固体電解質と電極活物質の双方がリン酸アニオン骨格を有する材料を含むことにより、焼成工程において電極層と固体電解質層とを密接に焼結接合することができる。 In one preferred embodiment of the all-solid battery of the present invention, the solid electrolyte and the electrode active material include a lithium-containing phosphate compound such as a lithium-containing phosphate compound having a NASICON structure and a lithium-containing phosphate compound having an olivine structure. . As described above, when both the solid electrolyte and the electrode active material contain a material having a phosphate anion skeleton, the electrode layer and the solid electrolyte layer can be closely sintered and joined in the firing step.
　本発明の全固体電池積層体１０の製造方法の一つの実施形態では、まず、固体電解質と電極活物質とを含む正極材料の成形体を作製する。固体電解質と電極活物質とを含む負極材料の成形体を作製する。固体電解質材料の成形体を作製する。この場合、上記の各々の成形体をグリーンシートの形態で作製することができる。そして、各々の成形体を積層して積層体を形成する。この積層体を焼成する。このようにして正極層１１と固体電解質層１３と負極層１２との積層体からなる全固体電池積層体１０を一体焼成により形成することができる。この場合、焼成温度は５００℃以上７００℃以下であることが好ましい。 In one embodiment of the method for producing the all solid state battery laminate 10 of the present invention, first, a molded body of a positive electrode material including a solid electrolyte and an electrode active material is produced. A molded body of a negative electrode material including a solid electrolyte and an electrode active material is produced. A compact of a solid electrolyte material is produced. In this case, each of the molded bodies can be produced in the form of a green sheet. And each molded object is laminated | stacked and a laminated body is formed. This laminate is fired. In this way, the all-solid battery laminate 10 composed of the laminate of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 can be formed by integral firing. In this case, the firing temperature is preferably 500 ° C. or higher and 700 ° C. or lower.
　本発明の全固体電池積層体１０の製造方法の好ましい一つの実施形態では、まず、正極層１１、固体電解質層１３、および、負極層１２の各々のスラリーを調製する（スラリー調製工程）。その後、正極層１１、固体電解質層１３、および、負極層１２の各々のスラリーを成形してグリーンシートを作製する（グリーンシート成形工程）。そして、正極層１１、固体電解質層１３、および、負極層１２の各々のグリーンシートを積層して積層体を形成する（積層体形成工程）。最後に、積層体を焼成する（焼成工程）。本発明の製造方法では、スラリー調製工程において、正極層１１または負極層１２のスラリーの少なくとも一方が、電極活物質と、炭素材料を含む導電剤とを含み、かつ、正極層１１または負極層１２のスラリーの少なくとも一方に含まれる炭素材料の含有量が１質量％以上２５質量％未満である。 In one preferred embodiment of the method for producing the all-solid battery stack 10 of the present invention, first, each slurry of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 is prepared (slurry preparation step). Thereafter, each of the slurry of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 is formed to produce a green sheet (green sheet forming step). And the green body of each of the positive electrode layer 11, the solid electrolyte layer 13, and the negative electrode layer 12 is laminated | stacked, and a laminated body is formed (laminated body formation process). Finally, the laminate is fired (firing step). In the production method of the present invention, in the slurry preparation step, at least one of the slurry of the positive electrode layer 11 or the negative electrode layer 12 includes an electrode active material and a conductive agent including a carbon material, and the positive electrode layer 11 or the negative electrode layer 12. The content of the carbon material contained in at least one of the slurries is 1% by mass or more and less than 25% by mass.
　上記のグリーンシートを成形する方法は特に限定されないが、ダイコーター、コンマコーター、スクリーン印刷などを使用することができる。グリーンシートを積層する方法は特に限定されないが、熱間等方圧プレス（ＨＩＰ）、冷間等方圧プレス（ＣＩＰ）、静水圧プレス（ＷＩＰ）などを使用してグリーンシートを積層することができる。グリーンシートの積層体を焼成するための雰囲気は特に限定されないが、電極活物質に含まれる遷移金属の価数が変化しない条件で行うことが好ましい。 The method for forming the green sheet is not particularly limited, but a die coater, a comma coater, screen printing, or the like can be used. The method of laminating the green sheets is not particularly limited, but the green sheets can be laminated using a hot isostatic press (HIP), a cold isostatic press (CIP), a hydrostatic press (WIP), or the like. it can. The atmosphere for firing the laminate of green sheets is not particularly limited, but it is preferably performed under conditions that do not change the valence of the transition metal contained in the electrode active material.
　本発明の全固体電池積層体１０においては、正極層１１または負極層１２の少なくとも一方と固体電解質層１３とが一体焼成によって接合されている。この場合、正極層１１または負極層１２の少なくとも一方と固体電解質層１３とが、複数のグリーンシートを積層して形成された積層体を焼成することによって接合されていることが好ましい。 In the all-solid battery laminate 10 of the present invention, at least one of the positive electrode layer 11 or the negative electrode layer 12 and the solid electrolyte layer 13 are joined by integral firing. In this case, it is preferable that at least one of the positive electrode layer 11 or the negative electrode layer 12 and the solid electrolyte layer 13 are joined by firing a laminate formed by laminating a plurality of green sheets.
　次に、本発明の実施例を具体的に説明する。なお、以下に示す実施例は一例であり、本発明は下記の実施例に限定されるものではない。 Next, specific examples of the present invention will be described. In addition, the Example shown below is an example and this invention is not limited to the following Example.
　以下、各種の電極活物質と固体電解質を用いて作製された全固体電池の実施例１～３と比較例について説明する。 Hereinafter, Examples 1 to 3 and comparative examples of all solid state batteries manufactured using various electrode active materials and solid electrolytes will be described.
　（実施例１） (Example 1)
　電極活物質材料として二酸化モリブデン（以下、ＭｏＯ2という）、固体電解質材料としてナシコン型構造のリチウム含有リン酸化合物の組成を有するガラス粉末Ｌｉ1.5Ａｌ0.5Ｇｅ1.5（ＰＯ4）3（以下、ＬＡＧＰという）、導電剤としてアセチレンブラック（以下、ＡＢという）を用いた。 Molybdenum dioxide (hereinafter referred to as MoO 2 ) as an electrode active material and glass powder Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (hereinafter referred to as LAGP) having a composition of a lithium-containing phosphate compound having a NASICON type structure as a solid electrolyte material ), And acetylene black (hereinafter referred to as AB) was used as a conductive agent.
　＜電極グリーンシート、固体電解質グリーンシートの作製＞ <Production of electrode green sheet and solid electrolyte green sheet>
　バインダとしてのポリビニルアルコールを含む溶液中に、電極活物質としてのＭｏＯ2の結晶粉末を混合して、電極活物質スラリー１を作製した。混合比は、質量比率で、ＭｏＯ2：ポリビニルアルコール＝８０：２０とした。 An electrode active material slurry 1 was prepared by mixing MoO 2 crystal powder as an electrode active material in a solution containing polyvinyl alcohol as a binder. The mixing ratio was MoO 2 : polyvinyl alcohol = 80: 20 in terms of mass ratio.
　固体電解質材料としてのＬＡＧＰのガラス粉末と、バインダとしてのポリビニルアルコールとを混合して、固体電解質スラリー１を作製した。混合比は、質量比率で、ＬＡＧＰ：ポリビニルアルコール＝８０：２０とした。 The glass powder of LAGP as a solid electrolyte material and polyvinyl alcohol as a binder were mixed to prepare a solid electrolyte slurry 1. The mixing ratio was LAGP: polyvinyl alcohol = 80: 20 in terms of mass ratio.
　導電剤としてのＡＢと、バインダとしてのポリビニルアルコールとを混合して、導電剤スラリー１を作製した。混合比は、質量比率で、ＡＢ：ポリビニルアルコール＝８０：２０とした。 A conductive agent slurry 1 was prepared by mixing AB as a conductive agent and polyvinyl alcohol as a binder. The mixing ratio was AB: polyvinyl alcohol = 80: 20 in terms of mass ratio.
　上記で作製された電極活物質スラリー１と固体電解質スラリー１と導電剤スラリー１とを、ＭｏＯ2とＬＡＧＰとＡＢの混合比が、質量比率で、ＭｏＯ2：ＬＡＧＰ：ＡＢ＝４５：４５：１０になるように混合して、電極スラリー１を作製した。 The electrode active material slurry 1, the solid electrolyte slurry 1, and the conductive agent slurry 1 produced above were mixed at a mass ratio of MoO 2 , LAGP, and AB, and MoO 2 : LAGP: AB = 45: 45: 10. Thus, electrode slurry 1 was prepared.
　以上のようにして作製された電極スラリー１と固体電解質スラリー１を、ドクターブレードを用いて、５０μｍの厚みに成形することにより、電極グリーンシート１と固体電解質グリーンシート１を作製した。 The electrode slurry 1 and the solid electrolyte green sheet 1 produced as described above were formed into a thickness of 50 μm using a doctor blade to produce an electrode green sheet 1 and a solid electrolyte green sheet 1.
　＜全固体電池の作製＞ <Production of all-solid-state battery>
　直径が１２ｍｍの円板形状に打ち抜いた固体電解質層１３用グリーンシート（固体電解質グリーンシート１）の一方面に、直径が１２ｍｍの円板形状に打ち抜いた負極層１２用グリーンシート（電極グリーンシート１）を、図４に示すような積層体の構成で積層し、８０℃の温度で１トンの圧力で熱圧着し、全固体電池積層体１１０の一部を構成する積層体を形成するためのグリーンシート積層体１を作製した。 A green sheet for the negative electrode layer 12 (electrode green sheet 1) punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. ) Is laminated in the configuration of the laminate as shown in FIG. 4 and thermocompression bonded at a temperature of 80 ° C. with a pressure of 1 ton to form a laminate constituting a part of the all-solid battery laminate 110. A green sheet laminate 1 was produced.
　グリーンシート積層体１を、２枚のアルミナ製のセラミックス板を用いて挟み込み、空気中にて５００℃の温度で焼成し、ポリビニルアルコールの除去を行った後、窒素ガス雰囲気中にて６００℃の温度で焼成して、図４に示すように、負極層１２と固体電解質層１３とを一体焼成によって接合することにより、全固体電池積層体１１０の一部を構成する積層体１を作製した。 The green sheet laminate 1 is sandwiched between two alumina ceramic plates, baked in air at a temperature of 500 ° C., and after removing polyvinyl alcohol, the glass sheet laminate is heated to 600 ° C. in a nitrogen gas atmosphere. As shown in FIG. 4, the negative electrode layer 12 and the solid electrolyte layer 13 were joined by integral firing to produce a laminate 1 constituting a part of the all-solid battery laminate 110.
　得られた積層体１を１００℃の温度で乾燥し、水分を除去した。その後、図４に示すように、正極層１１（対極）としての金属リチウム上にポリメタクリル酸メチル（ＰＭＭＡ）ゲル電解質１３１を塗布し、固体電解質層１３の面がＰＭＭＡゲル電解質１３１と接触するように正極層１１を積層して、全固体電池積層体１１０を作製した。全固体電池積層体１１０を２０３２型のコインセルで封止して全固体電池１を作製した。 The obtained laminate 1 was dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 4, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as positive electrode layer 11 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131. The positive electrode layer 11 was laminated to the all-solid battery laminate 110. The all solid state battery stack 110 was sealed with a 2032 type coin cell to produce the all solid state battery 1.
　＜全固体電池の評価＞ <Evaluation of all-solid-state battery>
　全固体電池１を１．３～３Ｖの電圧範囲、１００μＡ／ｃｍ2の電流密度で、定電流定電圧充放電測定を行った。図６に全固体電池１の充放電曲線を示す。ここで、負極の活物質として用いられたＭｏＯ2へのリチウム挿入によって電位が下降することを充電、ＭｏＯ2からのリチウム脱離によって電位が上昇することを放電と定義する。図６の横軸は、負極層に含まれる二酸化モリブデンの質量に対して、１グラム当たりの容量［ｍＡｈ／ｇ］を示す。その結果、図６に示すように、電極活物質（ＭｏＯ2）の単位質量当たりの放電容量が約１７０ｍＡｈ／ｇで充放電が可能であり、高い放電容量を示すことが確認された。また、放電時に１．４Ｖと１．７Ｖ（ｖ．ｓ．Ｌｉ）の電位で平坦域を示すことが確認された。 The all-solid-state battery 1 was subjected to constant current and constant voltage charge / discharge measurement at a voltage range of 1.3 to 3 V and a current density of 100 μA / cm 2 . FIG. 6 shows a charge / discharge curve of the all-solid battery 1. Here, a decrease in potential due to lithium insertion into MoO 2 used as the negative electrode active material is defined as charging, and a rise in potential due to lithium desorption from MoO 2 is defined as discharging. The horizontal axis of FIG. 6 shows the capacity [mAh / g] per gram with respect to the mass of molybdenum dioxide contained in the negative electrode layer. As a result, as shown in FIG. 6, it was confirmed that the discharge capacity per unit mass of the electrode active material (MoO 2 ) can be charged / discharged at about 170 mAh / g, and a high discharge capacity is exhibited. Further, it was confirmed that flat regions were exhibited at potentials of 1.4 V and 1.7 V (vs. Li) during discharge.
　（比較例） (Comparative example)
　比較例として、導電剤を含まない電極シートを用いた全固体電池を作製し、評価した。 As a comparative example, an all-solid battery using an electrode sheet not containing a conductive agent was prepared and evaluated.
　＜電極グリーンシート、固体電解質グリーンシートの作製＞ <Production of electrode green sheet and solid electrolyte green sheet>
　上記で作製された電極活物質スラリー１と固体電解質スラリー１とを、ＭｏＯ2とＬＡＧＰの混合比が、質量比率で、ＭｏＯ2：ＬＡＧＰ＝５０：５０になるように混合して、電極スラリー１ａを作製した。 The electrode active material slurry 1 and the solid electrolyte slurry 1 produced above are mixed so that the mixing ratio of MoO 2 and LAGP is MoO 2 : LAGP = 50: 50 in terms of mass ratio. Was made.
　以上のようにして作製された電極スラリー１ａを、ドクターブレードを用いて、５０μｍの厚みに成形することにより、電極グリーンシート１ａを作製した。 Electrode green sheet 1a was produced by forming electrode slurry 1a produced as described above to a thickness of 50 μm using a doctor blade.
　＜全固体電池の作製＞ <Production of all-solid-state battery>
　直径が１２ｍｍの円板形状に打ち抜いた固体電解質層１３用グリーンシート（固体電解質グリーンシート１）の一方面に、直径が１２ｍｍの円板形状に打ち抜いた負極層１２用グリーンシート（電極グリーンシート１ａ）を、図４に示すような積層体の構成で積層し、８０℃の温度で１トンの圧力で熱圧着し、全固体電池積層体１１０の一部を構成する積層体を形成するためのグリーンシート積層体１ａを作製した。 A green sheet for the negative electrode layer 12 (electrode green sheet 1a) punched into a disk shape with a diameter of 12 mm is formed on one surface of a green sheet for solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. ) Is laminated in the configuration of the laminate as shown in FIG. 4 and thermocompression bonded at a temperature of 80 ° C. with a pressure of 1 ton to form a laminate constituting a part of the all-solid battery laminate 110. A green sheet laminate 1a was produced.
　グリーンシート積層体１ａを、２枚のアルミナ製のセラミックス板を用いて挟み込み、空気中にて５００℃の温度で焼成し、ポリビニルアルコールの除去を行った後、窒素ガス雰囲気中にて６００℃の温度で焼成して、図４に示すように、負極層１２と固体電解質層１３とを一体焼成によって接合することにより、全固体電池積層体１１０の一部を構成する積層体１ａを作製した。 The green sheet laminate 1a is sandwiched between two alumina ceramic plates, fired in air at a temperature of 500 ° C., and after removal of polyvinyl alcohol, the temperature is 600 ° C. in a nitrogen gas atmosphere. As shown in FIG. 4, the negative electrode layer 12 and the solid electrolyte layer 13 were joined by integral firing to produce a laminate 1 a constituting a part of the all-solid battery laminate 110.
　得られた積層体１ａを１００℃の温度で乾燥し、水分を除去した。その後、図４に示すように、正極層１１（対極）としての金属リチウム上にポリメタクリル酸メチル（ＰＭＭＡ）ゲル電解質１３１を塗布し、固体電解質層１３の面がＰＭＭＡゲル電解質１３１と接触するように正極層１１を積層して、全固体電池積層体１１０を作製した。全固体電池積層体１１０を２０３２型のコインセルで封止して全固体電池１ａを作製した。 The obtained laminate 1a was dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 4, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as positive electrode layer 11 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131. The positive electrode layer 11 was laminated to the all-solid battery laminate 110. The all-solid battery stack 110 was sealed with a 2032 type coin cell to produce an all-solid battery 1a.
　＜全固体電池の評価＞ <Evaluation of all-solid-state battery>
　全固体電池１ａを１．４～３Ｖの電圧範囲、１００μＡ／ｃｍ2の電流密度で、定電流定電圧充放電測定を行った。その結果、電極活物質（ＭｏＯ2）の単位質量当たりの初期放電容量が約５０ｍＡｈ／ｇで充放電することが確認された。 The all-solid-state battery 1a was subjected to constant current constant voltage charge / discharge measurement at a voltage range of 1.4 to 3 V and a current density of 100 μA / cm 2 . As a result, it was confirmed that charging / discharging was performed at an initial discharge capacity per unit mass of the electrode active material (MoO 2 ) of about 50 mAh / g.
　以上の結果から、電極層に導電剤として機能する炭素粉末を混ぜることにより、電極層の電子伝導性を高めることができれば、電極活物質の容量を十分に高めることができ、有機電解液を用いた電池と同等程度に充放電できることが明らかになった。 From the above results, it is possible to sufficiently increase the capacity of the electrode active material by mixing the carbon powder functioning as a conductive agent into the electrode layer, and to increase the capacity of the electrode active material. It was revealed that the battery can be charged / discharged to the same extent as the conventional battery.
　なお、実施例１においては、炭素粉末としてアセチレンブラック（ＡＢ）を用いたものについてのみ説明を行ったが、炭素粉末はＡＢに限られることはなく、ケッチェンブラック、ファーネスブラックなどの炭素粉末を用いても同様の効果が得られる。 In addition, in Example 1, although only what used acetylene black (AB) as a carbon powder was demonstrated, carbon powder is not restricted to AB, Carbon powder, such as Ketjen black and furnace black, is used. Even if it is used, the same effect can be obtained.
　また、全固体電池積層体の封止方法は特に限定されず、焼結した積層体を樹脂で封止するなどしてもよい。Ａｌ2Ｏ3などの絶縁性のペーストを積層体の周囲に塗布またはディップし、これを熱処理して封止するなどしてもよい。正負極層から効率的に電流を引き出すために、正負極層の上にスパッタリングなどで金属層などの導電層を形成してもよい。正負極層の上に金属ペーストなどを塗布またはディップし、これを熱処理して導電層を形成するなどしてもよい。 Moreover, the sealing method of an all-solid-state battery laminated body is not specifically limited, You may seal the sintered laminated body with resin. An insulating paste such as Al 2 O 3 may be applied or dipped around the laminated body and heat-treated to seal it. In order to draw current efficiently from the positive and negative electrode layers, a conductive layer such as a metal layer may be formed on the positive and negative electrode layers by sputtering or the like. A conductive layer may be formed by applying or dipping a metal paste or the like on the positive and negative electrode layers and heat-treating it.
　（実施例２） (Example 2)
　電極活物質としてアナターゼ型酸化チタン（以下、ＴｉＯ2という）、固体電解質としてナシコン型構造のリチウム含有リン酸化合物の組成を有するガラス粉末ＬＡＧＰ、導電剤としてＡＢを用いた。 Anatase type titanium oxide (hereinafter referred to as TiO 2 ) was used as an electrode active material, glass powder LAGP having a composition of a lithium-containing phosphate compound having a NASICON type structure as a solid electrolyte, and AB was used as a conductive agent.
　＜電極グリーンシートの作製＞ <Production of electrode green sheet>
　バインダとしてのポリビニルアルコールを含む溶液中に、電極活物質としてのＴｉＯ2の結晶粉末を混合して、電極活物質スラリー２を作製した。混合比は、質量比率で、ＴｉＯ2：ポリビニルアルコール＝８０：２０とした。 An electrode active material slurry 2 was prepared by mixing TiO 2 crystal powder as an electrode active material in a solution containing polyvinyl alcohol as a binder. The mixing ratio was TiO 2 : polyvinyl alcohol = 80: 20 by mass ratio.
　上記で作製された電極活物質スラリー２と固体電解質スラリー１と導電剤スラリー１とを、ＴｉＯ2とＬＡＧＰとＡＢの混合比が、質量比率で、表１に示す値になるように混合して、電極スラリー２～８を作製した。 The electrode active material slurry 2, the solid electrolyte slurry 1 and the conductive agent slurry 1 prepared above were mixed so that the mixing ratio of TiO 2 , LAGP and AB was a mass ratio and the value shown in Table 1. Electrode slurries 2 to 8 were prepared.
　以上のようにして作製された電極スラリー２～８を、ドクターブレードを用いて、５０μｍの厚みに成形することにより、電極グリーンシート２～８を作製した。 Electrode green sheets 2 to 8 were produced by forming the electrode slurries 2 to 8 produced as described above to a thickness of 50 μm using a doctor blade.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　＜全固体電池の作製＞ <Production of all-solid-state battery>
　直径が１２ｍｍの円板形状に打ち抜いた固体電解質層１３用グリーンシート（固体電解質グリーンシート１）の一方面に、直径が１２ｍｍの円板形状に打ち抜いた負極層１２用グリーンシート（電極グリーンシート２～８のそれぞれ）を、図４に示すような積層体の構成で積層し、８０℃の温度で１トンの圧力で熱圧着し、全固体電池積層体１１０の一部を構成する積層体を形成するためのグリーンシート積層体２～８を作製した。 A green sheet for the negative electrode layer 12 (electrode green sheet 2) punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. To 8) are laminated in the structure of the laminated body as shown in FIG. 4 and thermocompression bonded at a temperature of 80 ° C. with a pressure of 1 ton to form a laminated body constituting a part of the all-solid-state battery laminated body 110. Green sheet laminates 2 to 8 for formation were produced.
　グリーンシート積層体２～８のそれぞれを、２枚のアルミナ製のセラミックス板を用いて挟み込み、空気中にて５００℃の温度で焼成し、ポリビニルアルコールの除去を行った後、窒素ガス雰囲気中にて６００℃の温度で焼成して、図４に示すように、負極層１２と固体電解質層１３とを一体焼成によって接合することにより、全固体電池１１０の一部を構成する積層体２～８を作製した。 Each of the green sheet laminates 2 to 8 is sandwiched between two alumina ceramic plates, fired in air at a temperature of 500 ° C. to remove polyvinyl alcohol, and then placed in a nitrogen gas atmosphere. As shown in FIG. 4, the negative electrode layer 12 and the solid electrolyte layer 13 are joined by integral firing, so that the laminates 2 to 8 constituting a part of the all-solid battery 110 are fired at a temperature of 600 ° C. Was made.
　得られた積層体２～８を１００℃の温度で乾燥し、水分を除去した。その後、図４に示すように、正極層１１（対極）としての金属リチウム上にポリメタクリル酸メチル（ＰＭＭＡ）ゲル電解質１３１を塗布し、固体電解質層１３の面がＰＭＭＡゲル電解質１３１と接触するように正極層１１を積層して、全固体電池積層体１１０を作製した。全固体電池積層体１１０を２０３２型のコインセルで封止して全固体電池２～８を作製した。 The obtained laminates 2 to 8 were dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 4, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as positive electrode layer 11 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131. The positive electrode layer 11 was laminated to the all-solid battery laminate 110. The all solid state battery stack 110 was sealed with a 2032 type coin cell to prepare all solid state batteries 2 to 8.
　その結果、表２の「焼結性」の欄に示すように、積層体７と８は、電極活物質と固体電解質の焼結が不十分であり、強度が他の積層体２～６に比べて低く、積層体８は取扱い時に割れやすかった。 As a result, as shown in the column “Sinterability” in Table 2, the laminates 7 and 8 have insufficient sintering of the electrode active material and the solid electrolyte, and the strengths of the laminates 2 to 6 are the same as those of the other laminates 2 to 6. Compared to this, the laminate 8 was easily broken during handling.
　＜全固体電池の評価＞ <Evaluation of all-solid-state battery>
　全固体電池２～８を１．４～３Ｖの電圧範囲、１００μＡ／ｃｍ2の電流密度で、定電流定電圧充放電測定を行った。全固体電池２～８（積層体２～８）について、電極活物質（ＴｉＯ2）の単位質量当たりの放電容量の測定結果を表２に示す。 The all-solid-state batteries 2 to 8 were subjected to constant current and constant voltage charge / discharge measurement in a voltage range of 1.4 to 3 V and a current density of 100 μA / cm 2 . Table 2 shows the measurement results of the discharge capacity per unit mass of the electrode active material (TiO 2 ) for all solid state batteries 2 to 8 (laminates 2 to 8).
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２から明らかなように、負極層１２の出発材料に含まれるＡＢの含有量が１０～３０質量部の積層体５～８にて、負極層１２の電子伝導性が高くなり、最も放電容量が大きくなることを確認した。しかし、上述したように積層体７と８は、電極活物質と固体電解質の焼結が不十分であり、強度が他の積層体２～６に比べて低いので、全固体電池を構成するために用いるのに適さなかった。ＡＢの含有量が少ない積層体４、３、２では、炭素含有量が少なくなるにつれて放電容量が小さくなることを確認した。 As is clear from Table 2, in the laminates 5 to 8 in which the AB content contained in the starting material of the negative electrode layer 12 is 10 to 30 parts by mass, the negative electrode layer 12 has the highest electronic conductivity and the highest discharge capacity. Was confirmed to be larger. However, as described above, the laminates 7 and 8 have insufficient sintering of the electrode active material and the solid electrolyte, and the strength thereof is lower than those of the other laminates 2 to 6, so that an all-solid battery is formed. It was not suitable for use. In the laminates 4, 3, and 2 having a low AB content, it was confirmed that the discharge capacity decreased as the carbon content decreased.
　（実施例３） (Example 3)
　電極活物質としてナシコン型構造のリチウム含有リン酸化合物の組成を有する無機結晶粉末Ｌｉ3Ｖ2（ＰＯ4）3（以下、ＬＶＰという）、固体電解質としてナシコン型構造のリチウム含有リン酸化合物の組成を有するガラス粉末ＬＡＧＰを用いた。ＬＶＰには、合成時に炭素粉末としてファーネスブラックを添加した。混合比は、質量比率で、ＬＶＰ：ファーネスブラック＝８５：１５とした。 Inorganic crystal powder Li 3 V 2 (PO 4 ) 3 (hereinafter referred to as LVP) having a composition of a lithium-containing phosphate compound having a NASICON structure as an electrode active material, and a composition of a lithium-containing phosphate compound having a NASICON structure as a solid electrolyte A glass powder LAGP having To LVP, furnace black was added as a carbon powder during synthesis. The mixing ratio was LVP: furnace black = 85: 15 in terms of mass ratio.
　＜電極グリーンシートの作製＞ <Production of electrode green sheet>
　バインダとしてのポリビニルアルコールをトルエンに溶解したバインダ溶液中に、電極活物質としてのＬＶＰの結晶粉末を混合して、電極活物質スラリー９を作製した。混合比は、質量比率で、（ＬＶＰ＋ファーネスブラック）：ポリビニルアルコール＝８０：２０とした。 An electrode active material slurry 9 was prepared by mixing LVP crystal powder as an electrode active material in a binder solution obtained by dissolving polyvinyl alcohol as a binder in toluene. The mixing ratio was (LVP + furnace black): polyvinyl alcohol = 80: 20 in terms of mass ratio.
　上記で作製された電極活物質スラリー９と固体電解質スラリー１とを、ＬＶＰとＬＡＧＰとファーネスブラックの混合比が、質量比率で、３５：５０：１５になるように混合して、電極スラリー９を作製した。 The electrode active material slurry 9 and the solid electrolyte slurry 1 produced above were mixed so that the mixing ratio of LVP, LAGP, and furnace black was 35:50:15, and the electrode slurry 9 was Produced.
　以上のようにして作製された電極スラリー９を、ドクターブレードを用いて、５０μｍの厚みに成形することにより、電極グリーンシート９を作製した。 The electrode slurry 9 produced as described above was formed into a thickness of 50 μm by using a doctor blade to produce an electrode green sheet 9.
　＜全固体電池の作製＞ <Production of all-solid-state battery>
　直径が１２ｍｍの円板形状に打ち抜いた固体電解質層１３用グリーンシート（固体電解質グリーンシート１）の一方面に、直径が１２ｍｍの円板形状に打ち抜いた正極層１１用グリーンシート（電極グリーンシート９）を、図５に示すような積層体の構成で積層し、８０℃の温度で１トンの圧力で熱圧着し、全固体電池積層体１２０の一部を構成する積層体を形成するためのグリーンシート積層体９を作製した。 A green sheet for the positive electrode layer 11 (electrode green sheet 9) punched into a disk shape with a diameter of 12 mm on one surface of a green sheet for the solid electrolyte layer 13 (solid electrolyte green sheet 1) punched into a disk shape with a diameter of 12 mm. ) In the configuration of the laminate as shown in FIG. 5 and thermocompression bonded at a pressure of 1 ton at a temperature of 80 ° C. to form a laminate constituting a part of the all-solid battery laminate 120 A green sheet laminate 9 was produced.
　グリーンシート積層体９を、２枚のアルミナ製のセラミックス板を用いて挟み込み、空気中にて５００℃の温度で焼成し、ポリビニルアルコールの除去を行った後、窒素ガス雰囲気中にて６００℃の温度で焼成して、図５に示すように、正極層１１と固体電解質層１３とを一体焼成によって接合することにより、全固体電池積層体１２０の一部を構成する積層体９を作製した。 The green sheet laminate 9 is sandwiched between two alumina ceramic plates, fired in air at a temperature of 500 ° C., and after removing polyvinyl alcohol, the glass sheet laminate 9 is heated to 600 ° C. in a nitrogen gas atmosphere. As shown in FIG. 5, the positive electrode layer 11 and the solid electrolyte layer 13 were joined by integral firing to produce a laminate 9 constituting a part of the all-solid battery laminate 120.
　得られた積層体９を１００℃の温度で乾燥し、水分を除去した。その後、図５に示すように、負極層１２（対極）としての金属リチウム上にポリメタクリル酸メチル（ＰＭＭＡ）ゲル電解質１３１を塗布し、固体電解質層１３の面がＰＭＭＡゲル電解質１３１と接触するように負極層１２を積層して、全固体電池積層体１２０を作製した。全固体電池積層体１２０を２０３２型のコインセルで封止して全固体電池９を作製した。 The obtained laminate 9 was dried at a temperature of 100 ° C. to remove moisture. Thereafter, as shown in FIG. 5, polymethyl methacrylate (PMMA) gel electrolyte 131 is applied on metallic lithium as negative electrode layer 12 (counter electrode) so that the surface of solid electrolyte layer 13 is in contact with PMMA gel electrolyte 131. A negative electrode layer 12 was laminated to the all-solid battery laminate 120. The all solid state battery laminate 120 was sealed with a 2032 type coin cell to produce the all solid state battery 9.
　＜全固体電池の評価＞ <Evaluation of all-solid-state battery>
　全固体電池９を３．０～４．５Ｖの電圧範囲、１００μＡ／ｃｍ2の電流密度で、定電流定電圧充放電測定を行った。その結果、電極活物質（ＬＶＰ）の単位質量当たりの放電容量が約１１０ｍＡｈ／ｇで充放電が可能であり、高い放電容量を示すことが確認された。 The all-solid-state battery 9 was subjected to constant current constant voltage charge / discharge measurement in a voltage range of 3.0 to 4.5 V and a current density of 100 μA / cm 2 . As a result, it was confirmed that charging / discharging was possible at a discharge capacity per unit mass of the electrode active material (LVP) of about 110 mAh / g, indicating a high discharge capacity.
　今回開示された実施の形態と実施例はすべての点で例示であって制限的なものではないと考慮されるべきである。本発明の範囲は以上の実施の形態と実施例ではなく、請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての修正と変形を含むものであることが意図される。 It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the claims.
　電極層と固体電解質層とを一体焼成によって接合しても、焼結性が良好で、十分な積層体の強度を得ることができるとともに、正極層内または負極層内に電子伝導性を付与することができるので、良好な充放電特性を示す全固体二次電池を提供することができる。 Even if the electrode layer and the solid electrolyte layer are joined by integral firing, the sinterability is good, sufficient strength of the laminate can be obtained, and electron conductivity is imparted in the positive electrode layer or the negative electrode layer. Therefore, it is possible to provide an all-solid secondary battery that exhibits good charge / discharge characteristics.
　１０：全固体電池積層体、１１：正極層、１２：負極層、１３：固体電解質層。

                                                                                 10: all-solid battery stack, 11: positive electrode layer, 12: negative electrode layer, 13: solid electrolyte layer.

Claims (4)

  1. 　正極層と、固体電解質を含む固体電解質層と、負極層とを備え、前記正極層または前記負極層の少なくとも一方と前記固体電解質層とが焼成によって接合された全固体電池であって、
    　前記正極層または前記負極層の少なくとも一方が、電極活物質と、炭素材料を含む導電剤とを含み、
    　前記正極層または前記負極層の少なくとも一方の出発材料に含まれる炭素材料の含有量が１質量％以上２５質量％未満である、全固体電池。     An all-solid battery comprising a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, and a negative electrode layer, wherein at least one of the positive electrode layer or the negative electrode layer and the solid electrolyte layer are joined by firing,
    At least one of the positive electrode layer or the negative electrode layer includes an electrode active material and a conductive agent including a carbon material,
    The all-solid-state battery whose content of the carbon material contained in at least one starting material of the said positive electrode layer or the said negative electrode layer is 1 mass% or more and less than 25 mass%.
  2. 　前記固体電解質または前記電極活物質の少なくとも一方が、リチウム含有リン酸化合物を含む、請求項１に記載の全固体電池。 The all-solid-state battery according to claim 1, wherein at least one of the solid electrolyte or the electrode active material contains a lithium-containing phosphate compound.
  3. 　前記固体電解質が、ナシコン型構造のリチウム含有リン酸化合物を含む、請求項１または請求項２に記載の全固体電池。 The all-solid-state battery according to claim 1 or 2, wherein the solid electrolyte includes a lithium-containing phosphate compound having a NASICON structure.
  4. 　請求項１から請求項３までのいずれか１項に記載の全固体電池の製造方法であって、
    　前記正極層、前記固体電解質層、および、前記負極層の各々のスラリーを調製するスラリー調製工程と、
    　前記正極層、前記固体電解質層、および、前記負極層の各々のスラリーを成形してグリーンシートを作製するグリーンシート成形工程と、
    　前記正極層、前記固体電解質層、および、前記負極層の各々のグリーンシートを積層して積層体を形成する積層体形成工程と、
    　前記積層体を焼成する焼成工程とを備え、
    　前記スラリー調製工程において、前記正極層または前記負極層のスラリーの少なくとも一方が、電極活物質と、炭素材料を含む導電剤とを含み、かつ、前記正極層または前記負極層のスラリーの少なくとも一方に含まれる炭素材料の含有量が１質量％以上２５質量％未満である、全固体電池の製造方法。     It is a manufacturing method of the all-solid-state battery of any one of Claim 1- Claim 3, Comprising:
    A slurry preparation step of preparing a slurry of each of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer;
    A green sheet forming step of forming a green sheet by forming a slurry of each of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer;
    A laminate forming step of forming a laminate by laminating the green sheets of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer;
    A firing step of firing the laminate,
    In the slurry preparation step, at least one of the positive electrode layer or the negative electrode layer slurry includes an electrode active material and a conductive agent including a carbon material, and at least one of the positive electrode layer or the negative electrode layer slurry. The manufacturing method of the all-solid-state battery whose content of the carbon material contained is 1 mass% or more and less than 25 mass%.
PCT/JP2011/075270 2010-11-04 2011-11-02 All-solid-state battery and method for manufacturing same WO2012060402A1 (en)

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EP3566842A1 (en) 2018-05-11 2019-11-13 Shin-Etsu Chemical Co., Ltd. Method for preparing ceramic molded body for sintering and method for producing ceramic sintered body
EP3567016A1 (en) 2018-05-11 2019-11-13 Shin-Etsu Chemical Co., Ltd. Method for preparing ceramic molded body for sintering and method for producing ceramic sintered body

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WO2013175992A1 (en) * 2012-05-24 2013-11-28 株式会社 村田製作所 All-solid-state battery
WO2013175991A1 (en) * 2012-05-24 2013-11-28 株式会社 村田製作所 All-solid-state battery and method for manufacturing same
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JP2015146240A (en) * 2014-02-03 2015-08-13 古河機械金属株式会社 Positive electrode material, positive electrode, and lithium ion battery
EP3566842A1 (en) 2018-05-11 2019-11-13 Shin-Etsu Chemical Co., Ltd. Method for preparing ceramic molded body for sintering and method for producing ceramic sintered body
EP3567016A1 (en) 2018-05-11 2019-11-13 Shin-Etsu Chemical Co., Ltd. Method for preparing ceramic molded body for sintering and method for producing ceramic sintered body
US11492294B2 (en) 2018-05-11 2022-11-08 Shin-Etsu Chemical Co., Ltd. Method for preparing ceramic molded body for sintering and method for producing ceramic sintered body

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