JP2017168282A - Electrode composite, battery, method for manufacturing electrode composite, and method for manufacturing battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode composite capable of effectively using an active material and a solid electrolyte, and a method for manufacturing the same.SOLUTION: An electrode composite 10 includes a porous first sintered body 1 containing positive active material particles 1a, a porous second sintered body 2 containing first solid electrolyte particles 2a, and a second solid electrolyte 3 filled in a laminate between the first sintered body 1 and the second sintered body 2.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electrode composite, a battery, a method for manufacturing an electrode composite, and a method for manufacturing a battery.

  As a battery, for example, in Patent Document 1, a composite material layer including a positive electrode or negative electrode active material, a sulfide glass layer in contact with the composite material layer, and a sulfide glass layer in contact with the composite material layer are opposed to each other. A solid state battery including a solid electrolyte containing glass ceramics is disclosed. According to Patent Document 1, the sulfide glass has viscosity and is in close contact with the surrounding active material, so that it is excellent in pressure moldability, and the electrical conductivity of the charge is improved by the close contact.

  Further, for example, in Patent Document 2, a glass whose glass transition temperature is lower than the decomposition temperature of the oxide solid electrolyte is disposed on the surface of the sintered body containing the oxide solid electrolyte, and the glass is melted and solidified. A method for producing a solid electrolyte member for a battery is disclosed. According to Patent Document 2, since the glass stays in the vicinity of the surface of the oxide solid electrolyte sintered body and seals the through hole, the amount of the through hole of the solid electrolyte member can be efficiently reduced by adding a small amount of glass. I can do it. The glass is preferably a glass electrolyte from the viewpoint of charge conductivity.

JP 2008-235227 A Japanese Patent Laying-Open No. 2015-185462

  However, in the solid battery using the solid battery of Patent Document 1 or the solid electrolyte member of Patent Document 2, sulfide glass or glass (glass electrolyte) and the granular active material are in contact with each other. There is a possibility that the charge conduction is not always efficiently performed in a portion where they are not in contact with each other. In other words, there is a problem that the active material cannot be used effectively.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example] An electrode assembly according to this application example includes a porous first sintered body containing an active material, a porous second sintered body containing a first solid electrolyte, and the first sintered body. And a second solid electrolyte filled in a laminate of the second sintered body.

  According to this application example, the active materials are in contact with each other in the first sintered body, and the first solid electrolytes are in contact with each other in the second sintered body. Therefore, electronic conduction between the active materials, ion diffusion, and ion transfer between the first solid electrolytes can be performed. Further, since the second solid electrolyte is filled in the gaps in the laminate of the first sintered body and the second sintered body, the ion transfer between the first sintered body and the second sintered body is also the first. It can be carried out via two solid electrolytes. Therefore, an electrode composite having excellent electron and ion conductivity can be provided by effectively using the active material and the first solid electrolyte.

In the electrode assembly according to the application example described above, it is preferable that the porosity of the first sintered body is the same as or larger than the porosity of the second sintered body.
According to this configuration, it is possible to increase the contact area between the active material and the second solid electrolyte as compared with the contact area between the first solid electrolyte and the second solid electrolyte, and the excellent charge (electrons and ions). An electrode composite having conductivity can be realized.

In the electrode assembly according to the application example, it is preferable that the thickness of the first sintered body is the same as or thicker than the thickness of the second sintered body.
According to this configuration, the electrical capacity of the electrode composite can be increased.

In the electrode assembly according to the application example, the first sintered body may include the first solid electrolyte formed on the surface of the active material.
According to this configuration, it is possible to increase the contact area between the active material and the first solid electrolyte, and it is possible to provide an electrode composite having more excellent ion conductivity.

In the electrode assembly according to the application example, the active material is a positive electrode active material made of a lithium composite metal compound.
According to this configuration, an electrode composite that can function as a positive electrode of a battery can be provided.

In the electrode assembly according to the application example, the active material is an oxide containing Li and Co, the first solid electrolyte is an oxide containing Li, La, and Zr, and the second solid electrolyte Is an oxide containing Li and B.
According to this configuration, an electrode composite having high lithium ion conductivity and capable of functioning as a positive electrode of a lithium ion battery can be provided.

[Application Example] A battery according to this application example includes the electrode composite according to the application example described above.
According to this application example, it is possible to provide a battery having excellent battery characteristics (charge / discharge characteristics).

  [Application Example] A method of manufacturing an electrode assembly according to this application example uses a first step of forming a porous first sintered body using particles of an active material, and particles of a first solid electrolyte. A second step of forming a porous second sintered body, and a third step of impregnating a laminate of the first sintered body and the second sintered body with a melt of the second solid electrolyte, And a fourth step of cooling the laminate impregnated with the melt of the second solid electrolyte.

  According to this application example, a first sintered body in which the active materials are in contact with each other is formed, and a second sintered body in which the first solid electrolytes are in contact with each other is formed. Therefore, charge can be transferred between the active materials or between the first solid electrolytes. Furthermore, since the second solid electrolyte is filled in the voids in the laminate of the first sintered body and the second sintered body, the charge transfer between the first sintered body and the second sintered body is also second. This can be done via a solid electrolyte. Therefore, an electrode assembly having excellent charge conductivity can be manufactured by effectively using the active material and the first solid electrolyte.

In the method for manufacturing an electrode assembly according to the application example described above, it is preferable that the melting point of the second solid electrolyte is lower than the melting points of the active material and the first solid electrolyte.
According to this method, when the second solid electrolyte is melted in the third step, the composition of the active material and the first solid electrolyte can be prevented from changing. That is, an electrode assembly having excellent charge conductivity can be stably produced with a high yield.

In the method for manufacturing an electrode assembly according to the application example, in the third step, a mixture containing the second solid electrolyte sandwiched between the first sintered body and the second sintered body is melted. It is preferable to make it.
According to this method, since the mixture in contact with each of the first sintered body and the second sintered body is melted, the second solid electrolyte is efficiently contained in the voids of the first sintered body and the second sintered body. Can be filled.

In the method for manufacturing an electrode composite according to the application example, the active material is a positive electrode active material made of a lithium composite metal compound.
According to this method, an electrode composite that can function as a positive electrode of a battery can be manufactured.

In the method for manufacturing an electrode assembly according to the application example, the active material is an oxide containing Li and Co, and the first solid electrolyte is an oxide containing Li, La, and Zr, The two solid electrolyte is an oxide containing Li and B, and in the third step, the second solid electrolyte is melted at a temperature of 700 ° C. or higher and lower than 900 ° C.
According to this method, Li can be prevented from separating from the active material and the first solid electrolyte in the heat treatment for melting the second solid electrolyte in the third step. Accordingly, the composition of the active material and the first solid electrolyte is hardly changed, and an electrode assembly having excellent charge conductivity can be stably manufactured with a high yield.

In the method for manufacturing an electrode assembly according to the application example, the first step includes a fifth step of impregnating the first sintered body with a solution containing the first solid electrolyte and a solvent, and the solution. And heating the first sintered body impregnated with a sixth step of removing the solvent.
According to this method, since the first solid electrolyte is formed on at least a part of the surface of the active material by the sixth step, the contact area between the active material and the first solid electrolyte can be increased. An electrode composite capable of efficiently transferring ions to and from the first solid electrolyte can be manufactured.

In the method for manufacturing an electrode assembly according to the application example, at least the third step of the first step, the second step, and the third step is performed in an atmosphere from which moisture is removed. Are preferred.
According to this method, it is possible to suppress the lithium hydroxide (LiOH) from being produced as a by-product due to the reaction with moisture, and the lithium ion conductivity from being lowered due to the composition change of the electrode assembly.

In the method for manufacturing an electrode assembly according to the application example, it is preferable that the second solid electrolyte is an oxide containing Li, C, and B, and the atmosphere in the third step contains carbon dioxide gas. .
According to this method, it is possible to suppress the reaction of Li in the active material and C in the second solid electrolyte to produce a by-product. That is, the composition of the active material and the second solid electrolyte is hardly changed, and an electrode assembly having excellent charge conductivity can be stably manufactured with a high yield.

[Application Example] The battery manufacturing method according to this application example includes a step of forming a current collector on at least one surface of the electrode assembly according to the application example.
According to this application example, a battery having excellent battery characteristics (charge / discharge characteristics) can be manufactured.

In the method for manufacturing a battery according to the application example, the active material is a positive electrode active material made of a lithium composite metal compound, and includes a step of forming a negative electrode on the other surface of the electrode composite. To do.
According to this method, a lithium ion battery having excellent electrical characteristics can be manufactured.

In the battery manufacturing method described in the application example, it is preferable that the method further includes a step of forming a lithium-resistant reduction layer between the other surface of the electrode composite and the negative electrode.
According to this method, a short circuit between the negative electrode and the first sintered body containing the active material can be prevented, and a lithium ion battery having excellent electrical characteristics can be manufactured with a high yield.

The schematic perspective view which shows the structure of the lithium ion battery of 1st Embodiment. 1 is a schematic cross-sectional view showing the structure of a lithium ion battery according to a first embodiment. The flowchart which shows the manufacturing method of the electrode composite_body | complex of 1st Embodiment. The schematic sectional drawing which shows the manufacturing method of the electrode composite_body | complex of 1st Embodiment. The schematic sectional drawing which shows the manufacturing method of the electrode composite_body | complex of 1st Embodiment. 1 is a schematic cross-sectional view showing a method for manufacturing a lithium ion battery according to a first embodiment. 1 is a schematic cross-sectional view showing a method for manufacturing a lithium ion battery according to a first embodiment. The schematic sectional drawing which shows the structure of the lithium ion battery of 2nd Embodiment. The schematic sectional drawing which shows the manufacturing method of the lithium ion battery of 2nd Embodiment. The schematic sectional drawing which shows the structure of the lithium ion battery of 3rd Embodiment. The flowchart which shows the manufacturing method of the electrode composite_body | complex of 3rd Embodiment. The schematic sectional drawing which shows the manufacturing method of the electrode composite_body | complex of 3rd Embodiment. The schematic sectional drawing which shows the manufacturing method of the electrode composite_body | complex of 3rd Embodiment. The schematic sectional drawing which shows the manufacturing method of the electrode composite_body | complex of 3rd Embodiment. The schematic sectional drawing which shows the manufacturing method of the electrode composite_body | complex of 3rd Embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.

(First embodiment)
<Battery>
First, as a battery to which the electrode assembly of this embodiment is applied, a lithium ion battery will be described as an example and described with reference to FIGS. 1 and 2. FIG. 1 is a schematic perspective view showing the configuration of the lithium ion battery of the first embodiment, and FIG. 2 is a schematic sectional view showing the structure of the lithium ion battery of the first embodiment.

  As shown in FIG. 1, a lithium ion battery 100 as a battery according to the present embodiment includes a pair of current collectors 41 and 42, an electrode assembly 10 provided between the pair of current collectors 41 and 42, and A negative electrode 30 is provided. The negative electrode 30 is a metal lithium layer, for example, and serves as a lithium ion source in charging / discharging of the lithium ion battery 100. The lithium ion battery 100 has, for example, a disk shape with an outer diameter of φ3.0 mm to 30 mm and a thickness of, for example, 100 μm to 150 μm (micrometer). The shape of the thin lithium ion battery 100 is not limited to this, and the outer shape may be a polygon.

  The current collectors 41 and 42 are electrodes for taking out current generated by the battery reaction. The current collector 41 is disposed in contact with the electrode assembly 10. The current collector 42 is disposed in contact with the negative electrode 30.

  As the current collectors 41 and 42, copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), indium (In), gold (Au), platinum (Pt), silver (Ag) and one kind of single metal selected from the group consisting of palladium (Pd), or two or more kinds selected from this group It is formed using a metal-containing alloy, a conductive metal oxide such as ITO, ATO, or FTO, or a metal nitride such as TiN, ZrN, or TaN. The shape of the current collectors 41 and 42 is, for example, a plate shape, a foil shape, or a net shape. The surfaces of the current collectors 41 and 42 may be smooth or uneven.

<Electrode complex>
As shown in FIG. 2, the electrode composite 10 is formed by sintering the first sintered body 1 obtained by sintering the plurality of positive electrode active material particles 1a and the plurality of first solid electrolyte particles 2a. The obtained second sintered body 2 and the second solid electrolyte 3 are included. The first sintered body 1 and the second sintered body 2 are each porous, and the voids included in each of the first sintered body 1 and the second sintered body 2, The voids of the laminate in which the second sintered body 2 is laminated are filled with the second solid electrolyte 3. FIG. 2 schematically shows the positive electrode active material particles 1a and the first solid electrolyte particles 2a. The actual individual particle shapes are not necessarily spherical and the sizes are not necessarily the same.

As the positive electrode active material constituting the positive electrode active material particle 1a, a lithium composite metal compound containing two or more metals including lithium (Li) is used. Examples of the lithium composite metal compound include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , Li ₂ Mn ₂ O ₃ , LiFePO ₄ , Li ₂ FeP ₂ O ₇ , LiMnPO ₄ , LiFeBO ₃ , Li ₃ V ₂ (PO ₄ ) ₃ , Li ₂ CuO ₂ , Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ and other lithium composite oxides. In addition to the lithium composite oxide, a lithium composite fluoride such as LiFeF ₃ may be used. Furthermore, those in which some atoms of these lithium composite metal compounds are substituted with other transition metals, typical metals, alkali metals, alkali rare earths, lanthanoids, chalcogenides, halogens and the like are also included. Moreover, you may use the solid solution of these lithium composite metal compounds as a positive electrode active material.

  From the viewpoint of effectively using the positive electrode active material, the average particle diameter (D50) of the positive electrode active material particles 1a is preferably 0.1 μm or more and 20 μm or less, and more preferably 1.0 μm or more and 10 μm or less.

As the first solid electrolyte constituting the first solid electrolyte particle 2a, for example, an oxide, sulfide, halide, or nitride of lithium (Li) is used. _{Specifically, SiO 2 -P 2 O 5 -Li} 2 O, SiO 2 -P 2 O 5 -LiCl, Li 2 O-LiCl-B 2 O 3, Li 3.4 V 0.6 Si 0.4 O 4, Li 14 ZnGe ₄ O ₁₆ , Li _3.6 V _0.4 Ge _0.6 O ₄ , Li _1.3 Ti _1.7 Al _0.3 (PO ₄ ) ₃ , Li _2.88 PO _3.73 N _0.14 , LiNbO ₃ , Li _0.35 La _0.55 TiO ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li _6.75 La ₃ Zr _1.75 Nb _0.25 O ₁₂ , Li ₂ S—SiS ₂ , Li ₂ S—SiS ₂ —LiI, Li ₂ S—SiS ₂ —P ₂ S ₅ , LiPON, Li ₃ N, LiI, LiI— _{CaI 2, LiI-CaO, LiAlCl} 4, LiAlF 4, LiI-Al 2 O 3, LiFAl 2 O 3, LiBr-Al 2 O 3, Li 2 O-TiO 2, La 2 O 3 -Li 2 O-TiO 2 , Li ₃ N, Li ₃ NI ₂ , Li ₃ N-LiI-L iOH, Li ₃ N—LiCl, Li ₆ NBr ₃ , LiSO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ —Li ₄ SiO ₄ , Li ₄ GeO ₄ —Li ₃ VO ₄ , Li ₄ SiO ₄ —Li ₃ VO _{4 , Li 4 GeO 4 -Zn 2 GeO} 2, Li 4 SiO 4 -LiMoO 4, Li 3 PO 4 -Li 4 SiO 4, LiSiO 4 -Li 4 ZrO 4, LiBH 4, Li 7-x PS 6-x Cl x , At least one of Li ₁₀ GeP ₂ S ₁₂ is used. The first solid electrolyte may be crystalline or amorphous. In addition, a solid solution in which some atoms of these compositions are substituted with another transition metal, typical metal, alkali metal, alkali rare earth, lanthanoid, chalcogenide, halogen, or the like may be used as the first solid electrolyte.

  From the viewpoint of effectively using the first solid electrolyte, the average particle diameter (D50) of the first solid electrolyte particles 2a is preferably 0.1 μm or more and 20 μm or less, and more preferably 1.0 μm or more and 10 μm or less. preferable.

The second solid electrolyte 3 is preferably a material that conducts lithium ions and is amorphous (glassy or amorphous) at room temperature, and a material having a melting point lower than that of the positive electrode active material or the first solid electrolyte is selected. It is. Examples of the second solid electrolyte 3 include Li ₃ BO ₃ , Li ₃ BO ₃ —Li ₄ SiO ₄ , Li ₃ BO ₃ —Li ₃ PO ₄ , Li ₃ BO ₃ —Li ₂ SO ₄ , Li _2. A lithium composite oxide containing Li and B such as CO ₃ —Li ₃ BO ₃ can be used.

Li ₃ BO ₃ (hereinafter referred to as LBO) has an ionic conductivity of approximately 6.0 × 10 ⁻¹⁰ S / cm and a melting point of approximately 820 ° C. Li ₃ BO ₃ —Li ₄ SiO _{4 has} an ionic conductivity of approximately 4.0 × 10 ⁻⁶ S / cm and a melting point of approximately 720 ° C. Li ₃ BO ₃ —Li ₃ PO _{4 has} an ionic conductivity of approximately 1.0 × 10 ⁻⁷ S / cm and a melting point of approximately 850 ° C. Li ₃ BO ₃ —Li ₂ SO _{4 has} an ionic conductivity of approximately 1.0 × 10 ⁻⁶ S / cm and a melting point of approximately 700 ° C. The ionic conductivity of Li _2.2 C _0.8 B _0.2 O ₃ (hereinafter simply referred to as LCBO), which is a Li ₂ CO ₃ —Li ₃ BO ₃ system, is approximately 8.0 × 10 ⁻⁷ S / cm, The melting point is 685 ° C.

From the viewpoint of increasing the capacity of the lithium ion battery 100, the ionic conductivity of the first solid electrolyte particles 2a is preferably 1.0 × 10 ⁻⁵ S / cm or more. The electrode composite 10 includes the second sintered body 2 by including the second sintered body 2 in which the plurality of first solid electrolyte particles 2 a having higher ion conductivity than the second solid electrolyte 3 are sintered. More positive electrode active material particles 1a contribute to the battery reaction, and the capacity of the lithium ion battery 100 can be increased as compared to the case where there is no.

  Here, the ionic conductivity of the solid electrolyte is the bulk conductivity that is the ionic conductivity of the inorganic electrolyte itself, and the grain boundary conductivity that is the ionic conductivity between the particles of the crystal when the inorganic electrolyte is crystalline. The total ionic conductivity, which is the sum of

  The ionic conductivity of the solid electrolyte is measured by, for example, an AC impedance method. The measurement is performed using, for example, a sample in which electrodes are formed on both surfaces of a solid electrolyte formed into a predetermined shape (for example, a tablet shape). More specifically, the solid electrolyte powder is press-molded into a tablet shape. The press-molded body is sintered in an air atmosphere. An electrode (for example, Au (gold) or Pt (platinum)) having a predetermined shape (for example, a circle having a diameter of 0.5 cm and a thickness of 100 nm) is formed on the sintered body using a sputtering method or a vacuum deposition method. The measurement is performed using, for example, an impedance analyzer (SI1260 manufactured by Solartron).

  As described above, the first sintered body 1 composed of the plurality of positive electrode active material particles 1a and the second sintered body 2 composed of the plurality of first solid electrolyte particles 2a are porous and include a plurality of voids ( Pores). These voids communicate with each other inside the first sintered body 1 and the second sintered body 2.

  The porosity of each sintered body is preferably 10% or more and 70% or less, and more preferably 30% or more and 70% or less. By controlling the porosity and increasing the contact area with the second solid electrolyte 3, the capacity of the lithium ion battery 100 can be further increased.

ここで、Ｖｇは各焼結体の見かけ上の体積を示す。見かけ上の体積は各焼結体の外形寸法から計算されるものであり、空隙を含んでいる。ｍは各焼結体の質量を、ρは各焼結体を構成する正極活物質粒子１ａあるいは第１固体電解質粒子２ａの密度を、それぞれ示している。詳しくは後述するが、各焼結体の空隙率ｒｖは、各焼結体を形成する工程において制御することができる。 The porosity rv can be obtained by the following equation (1).

Here, Vg represents the apparent volume of each sintered body. The apparent volume is calculated from the outer dimensions of each sintered body and includes voids. m represents the mass of each sintered body, and ρ represents the density of the positive electrode active material particles 1a or the first solid electrolyte particles 2a constituting each sintered body. As will be described in detail later, the porosity rv of each sintered body can be controlled in the step of forming each sintered body.

  From the viewpoint of increasing the output of the lithium ion battery 100, the resistivity of the first sintered body 1 is preferably 10 kΩcm or less. The resistivity is obtained, for example, by direct current polarization measurement. In the DC polarization measurement, for example, a copper foil is attached to the surface of each sintered body, and this copper foil is used as an electrode.

  The voids in the laminate of the first sintered body 1 and the second sintered body 2 are filled with the second solid electrolyte 3 and are in contact with the positive electrode active material particles 1a and the first solid electrolyte particles 2a. Although it is preferable that the filling rate of the second solid electrolyte 3 with respect to the voids of each sintered body is high, it is, for example, 60% or more and 99.9% or less.

In each sintered body, a plurality of voids communicate with each other in a mesh shape. For example, LiCoO ₂ (hereinafter simply referred to as LCO), which is an example of a positive electrode active material, is known to have anisotropy in the electronic conductivity of crystals. Therefore, when the gap extends in a specific direction, depending on the relationship between the direction in which the gap extends and the crystal orientation, it may be difficult to conduct electrons. In the present embodiment, the voids of the first sintered body 1 are communicated in a mesh shape, and the positive electrode active material particles 1a are also isotropically connected. Therefore, the electrochemically smooth continuous surface of the positive electrode active material particles 1a can be formed, and better electron conduction can be obtained as compared with the case where the voids are anisotropically formed.

  Each sintered body has a large surface area because it has a large number of voids inside. Therefore, the contact area between each sintered body and the second solid electrolyte 3 is increased, and the interface impedance can be reduced. In the lithium ion battery 100, the contact area between the first sintered body 1 and the second solid electrolyte 3 is larger than the contact area between the current collector 41 and the first sintered body 1. Similarly, the contact area between the second sintered body 2 and the second solid electrolyte 3 is larger than the contact area between the current collector 42 and the second sintered body 2. Since the interface between the current collector 41 and the first sintered body 1 is easier to transfer charges than the interface between the first sintered body 1 and the second solid electrolyte 3, their contact areas are about the same. If so, the interface between the first sintered body 1 and the second solid electrolyte 3 becomes a bottleneck for charge transfer. In this embodiment, since the contact area of the 1st sintered compact 1 and the 2nd solid electrolyte 3 is larger, it is easy to eliminate this bottleneck. The interface between the current collector 42 and the second solid electrolyte 3 with respect to the second sintered body 2 is the same as that of the first sintered body 1.

  The charge indicates ions or electrons. From the viewpoint of effectively using the charge conductivity in the positive electrode active material particle 1a, the porosity of the first sintered body 1 is the void of the second sintered body 2. The rate is preferably the same or larger. From the viewpoint of securing the battery capacity in the lithium ion battery 100, the thickness of the first sintered body 1 is preferably the same as or thicker than the thickness of the second sintered body 2.

<Method for producing electrode composite>
Next, the manufacturing method of the electrode assembly 10 of this embodiment is demonstrated with reference to FIGS. FIG. 3 is a flowchart showing a method for manufacturing the electrode assembly of the first embodiment, and FIGS. 4 and 5 are schematic cross-sectional views showing a method for manufacturing the electrode assembly of the first embodiment.

  As shown in FIG. 3, the manufacturing method of the electrode assembly 10 of the present embodiment includes a first sintered body forming step (step S1), a second sintered body forming step (step S2), and a second solid electrolyte. A filling process (step S3) and a composite process (step S4) are provided. Step S1 corresponds to the first step of the present invention, step S2 corresponds to the second step of the present invention, step S3 corresponds to the third step of the present invention, and step S4 corresponds to the step of the present invention. This corresponds to the fourth step.

  In the first sintered body forming step of step S1, first, as the positive electrode active material particles 1a, for example, LCO particles having an average particle diameter (D50) of 1 μm to 10 μm were used. For example, 150 mg of LCO particles were weighed and filled in a 10 mm diameter die (molding die), and uniaxial pressing was performed for 2 minutes at a pressure of 50 kgN to produce a pellet (molded body). The pellet is placed on a substrate and fired using, for example, an electric muffle furnace. The firing temperature is preferably 850 ° C. or higher and lower than the melting point of the positive electrode active material particles 1a. In this case, since the LCO particles are used as the positive electrode active material particles 1a, the firing temperature is preferably 875 ° C. or higher and 1000 ° C. or lower. Thereby, the positive electrode active material particles 1a are sintered together to obtain an integrated porous body. By setting the firing temperature to 850 ° C. or higher, sintering proceeds sufficiently and electron conductivity in the crystal of the positive electrode active material particles 1a is ensured. By setting the firing temperature below the melting point of the positive electrode active material particles 1a, lithium ions in the crystals of the positive electrode active material particles 1a are prevented from volatilizing excessively, and the conductivity of the lithium ions is maintained. That is, the capacity of the electrode assembly 10 can be ensured. Therefore, an appropriate output and capacity can be provided in the lithium ion battery 100 using the electrode assembly 10.

  Note that the pellet may be formed by including an organic substance such as a binder (binder) for joining the positive electrode active material particles 1a and a pore increasing material for adjusting the porosity of the first sintered body 1. However, if these organic substances remain after firing, the charge conductivity is affected. Therefore, it is preferable to surely burn off the organic substances by firing. In other words, it is desirable to form the pellet without containing an organic substance such as a binder or a pore expanding material. The porosity in the first sintered body 1 can be controlled by adjusting the average particle diameter of the positive electrode active material particles 1a and the sintering conditions such as the pressure and the firing temperature when forming the pellets. .

  The firing time is preferably, for example, 5 minutes or more and 36 hours or less. More preferably, it is 4 hours or more and 14 hours or less. By the above treatment, the porous first sintered body 1 is obtained. The material of the substrate used at the time of firing is not particularly limited, but it is preferable to use a material such as magnesium oxide that hardly reacts with the positive electrode active material particles 1a. Then, the process proceeds to step S2.

In the second sintered body forming step of Step S2, first, for example, Li _6.75 La ₃ Zr _1.75 Nb _0.25 O ₁₂ (hereinafter simply referred to as LLZrNbO) was used as the first solid electrolyte particles 2a. The average particle diameter (D50) of the LLZrNbO particles is, for example, 1.0 μm or more and 20 μm or less. The melting point of LLZrNbO is about 1100 ° C.

  For example, 150 mg of LLZrNbO particles were weighed and filled in a φ10 mm die, and uniaxial pressing was performed at a pressure of 50 kgN for 2 minutes to produce pellets (molded bodies). The pellet is placed on a substrate and fired using, for example, an electric muffle furnace. The firing temperature is preferably 850 ° C. or higher and lower than the melting point of the first solid electrolyte particles 2a. In this case, since LLZrNbO particles are used as the first solid electrolyte particles 2a, the firing temperature is preferably 875 ° C. or higher and 1000 ° C. or lower. Thereby, the 1st solid electrolyte particles 2a are sintered and the integrated porous body is obtained. By setting the firing temperature to 850 ° C. or higher, sintering proceeds sufficiently, and lithium ion conductivity in the crystals of the first solid electrolyte particles 2a is ensured. By setting the firing temperature below the melting point of the first solid electrolyte particles 2a, the lithium ions in the crystals of the first solid electrolyte particles 2a are prevented from excessively volatilizing, and the conductivity of the lithium ions is maintained. That is, in the lithium ion battery 100 using the electrode assembly 10, appropriate ion conductivity can be imparted.

  In addition, it is desirable to form a pellet without including organic substances, such as a binder and a pore enlargement material similarly to the 1st sintered compact formation process of step S1. Moreover, the porosity in the 2nd sintered compact 2 can be controlled by adjusting the average particle diameter of the 1st solid electrolyte particle 2a, and sintering conditions, such as the pressure at the time of forming a pellet, and a calcination temperature. it can.

  The firing time is preferably, for example, 5 minutes or more and 36 hours or less. More preferably, it is 4 hours or more and 14 hours or less. By the above treatment, the porous second sintered body 2 is obtained. Although the material of the board | substrate used at the time of baking is not specifically limited, It is preferable to use materials, such as magnesium oxide which are hard to react with a 1st solid electrolyte similarly to step S1. Then, the process proceeds to step S3.

In the second solid electrolyte filling step of step S3, first, pellets (molded bodies) of the second solid electrolyte 3 are prepared. Specifically, Li ₂ CO ₃ and Li ₃ BO ₃ which are powders are mixed at a mass mixing ratio of 4: 1, and the mixture is weighed, for example, 150 mg, filled into a φ10 mm die, and 1 kg at a pressure of 40 kgN. A shaft press was performed for 2 minutes to obtain tablets. This tablet was placed in an electric muffle furnace, for example, and baked at 650 ° C. for 4 hours. Then, the baked tablet is put in, for example, an agate mortar and crushed and pulverized, and the pulverized powder is again filled in a φ10 mm die, and uniaxial pressing is performed at a pressure of 40 kgN for 2 minutes to form the second solid electrolyte 3. A pellet 3p (see FIG. 4) was obtained. The mixing ratio of Li ₂ CO ₃ and Li ₃ BO ₃ in the above mixture is not limited to 4: 1, and the content of Li ₂ CO ₃ is preferably 30% or more and 95% or less.

  Subsequently, as shown in FIG. 4, the pellets 3p of the second solid electrolyte 3 are obtained by performing heat treatment with the pellets 3p sandwiched between the first sintered body 1 and the second sintered body 2. Melt. Since the pellet 3p is melted in contact with the first sintered body 1 and the second sintered body 2, the melt of the pellet 3p is a porous first sintered body 1 and second sintered body. Soak into 2 evenly.

  The temperature in the heat treatment is preferably a temperature not lower than the melting point of the second solid electrolyte 3 and not higher than 900 ° C. In this case, since LCBO is used as the second solid electrolyte 3, the temperature of the heat treatment was set to 700 ° C. higher than the melting point of LCBO (685 ° C.). Then, the process proceeds to step S4.

  In the composite process of step S4, the laminated body of the first sintered body 1 and the second sintered body 2 into which the melt of the second solid electrolyte 3 has been immersed is cooled. As a result, the melt of the second solid electrolyte 3 filled in the laminate in which the first sintered body 1 and the second sintered body 2 are laminated is solidified, and as shown in FIG. An electrode assembly 10 in which the body 1 and the second sintered body 2 and the second solid electrolyte 3 were combined was obtained.

  In addition, it is preferable to perform at least step S3 among the above-described steps S1, S2, and S3 subjected to heat treatment such as firing in an atmosphere from which moisture has been removed (for example, the moisture content is 130 ppm or less). Thus, lithium (Li) and water react to generate lithium hydroxide (LiOH) as a by-product, and the composition of the electrode assembly 10 can be prevented from changing from a desired state. In addition, when LCBO is used as the second solid electrolyte 3 in the above step S3, it is preferable to introduce carbon dioxide gas into the atmosphere from which moisture has been removed, whereby the composition of the carbon (C) is released from the LCBO. It can be prevented from changing.

<Method for producing lithium ion battery>
Next, the manufacturing method of the lithium ion battery 100 of this embodiment is demonstrated with reference to FIG.6 and FIG.7. 6 and 7 are schematic cross-sectional views showing a method for manufacturing a lithium ion battery.
The method for manufacturing the lithium ion battery 100 includes a step of forming the negative electrode 30 on the electrode assembly 10 obtained by the above-described manufacturing method and a step of forming the current collectors 41 and 42.

  In the step of forming the negative electrode 30, as shown in FIG. 6, the negative electrode 30 is formed on the surface 10 b where the second sintered body 2 is exposed in the electrode composite 10. Specifically, metallic lithium is deposited on the surface 10b by, for example, a sputtering method or a vacuum deposition method to form the negative electrode 30. The film thickness of the negative electrode 30 is, for example, 50 nm to 100 μm. In addition, the negative electrode 30 should just become a lithium ion supply source, for example, a lithium composite metal compound can be used besides metal lithium. In that case, in addition to a so-called sol-gel method involving a hydrolysis reaction of an organometallic compound, a solution process such as an organometallic pyrolysis method, a CVD method using an appropriate metal compound and a gas atmosphere, an ALD method The negative electrode 30 may be formed by using a green sheet method, a screen printing method, an aerosol deposition method, or the like using a slurry of metal compound particles.

  Next, in the step of forming the current collectors 41 and 42, as shown in FIG. 7, the current collector 41 is formed on the surface 10 a where the first sintered body 1 is exposed in the electrode assembly 10, and the negative electrode 30 is formed. The current collector 42 is formed by stacking. Specifically, the current collector 41 is formed by attaching, for example, an aluminum foil having a thickness of 1 μm to 20 μm to the surface 10 a which is one surface of the electrode assembly 10. Moreover, it is set as the collector 42 by sticking the copper foil whose thickness is 1 micrometer-20 micrometers to the negative electrode 30, for example. The method of forming the current collectors 41 and 42 is not limited to the method of attaching the metal foil selected as described above, but is a PVD (Physical Vapor Deposition) method, a CVD (Chemical Vapor Deposition) method, or a PLD (Pulsed Laser). Deposition method, vapor deposition method such as ALD (Atomic Layer Deposition) method and aerosol deposition method, sol-gel method, organometallic thermal decomposition method, wet method such as plating, etc. An appropriate method can be used according to the reactivity with the current collector forming surface, the electrical conductivity desired for the electrical circuit, and the electrical circuit design.

According to the first embodiment, the following effects can be obtained.
(1) The electrode composite 10 includes a porous first sintered body 1 composed of positive electrode active material particles 1a, a porous second sintered body 2 composed of first solid electrolyte particles 2a, and a first sintered body. A second solid electrolyte 3 filled in a laminate of the body 1 and the second sintered body 2 is configured. The second solid electrolyte 3 is also filled in the voids inside the first sintered body 1 and the second sintered body 2. In the first sintered body 1, the positive electrode active material particles 1 a are in contact with each other, and in the second sintered body 2, the first solid electrolyte particles 2 a are in contact with each other. Therefore, the transfer of electrons between the positive electrode active material particles 1a and the transfer of ions between the first solid electrolyte particles 2a are easily performed. Furthermore, since the second solid electrolyte 3 is filled in the gap in the laminated body of the first sintered body 1 and the second sintered body 2, the gap between the first sintered body 1 and the second sintered body 2. Charges (electrons and ions) can also be transferred via the second solid electrolyte 3. Therefore, it is possible to provide the electrode assembly 10 having excellent charge conductivity by effectively using the positive electrode active material particles 1a and the first solid electrolyte particles 2a.

  (2) According to the method for manufacturing the electrode assembly 10, in step S3, the pellets 3p of the second solid electrolyte 3 are sandwiched between the porous first sintered body 1 and the second sintered body 2, respectively. The pellet 3p is melted by performing a heat treatment in, and the melt of the second solid electrolyte 3 is filled in the gaps between the first sintered body 1 and the second sintered body 2. In step S <b> 4, the melt of the second solid electrolyte 3 is solidified by cooling, and the second solid electrolyte 3 is filled in the laminate of the first sintered body 1 and the second sintered body 2. That is, the first sintered body 1 and the second sintered body 2 are bonded by the second solid electrolyte 3. Therefore, compared with the case where one porous sintered body is formed using the positive electrode active material particles 1 a and the first solid electrolyte particles 2 a and the sintered body is impregnated with the melt of the second solid electrolyte 3. The contact between the positive electrode active material particles 1a and the contact between the first solid electrolyte particles 2a can be reliably achieved. Therefore, as shown in (1) above, the electrode composite 10 having excellent charge conductivity can be manufactured by effectively using the positive electrode active material particles 1a and the first solid electrolyte particles 2a.

  (3) By using the electrode assembly 10, it is possible to provide or manufacture a lithium ion battery 100 having excellent battery characteristics (charge / discharge characteristics) and having a large electric capacity despite being small and thin. it can.

(Second Embodiment)
Next, the lithium ion battery of 2nd Embodiment and its manufacturing method are demonstrated with reference to FIG.8 and FIG.9. FIG. 8 is a schematic cross-sectional view showing the structure of the lithium ion battery of the second embodiment, and FIG. 9 is a schematic cross-sectional view showing a method for manufacturing the lithium ion battery of the second embodiment. The lithium ion battery according to the second embodiment is different from the lithium ion battery 100 according to the first embodiment in the layer configuration of the battery. Therefore, the same components as those of the lithium ion battery 100 are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 8, the lithium ion battery 200 of the present embodiment includes a pair of current collectors 41 and 42, an electrode assembly 10 provided between the pair of current collectors 41 and 42, and lithium-resistant reduction. The layer 20 and the negative electrode 30 are included. The lithium ion battery 200 is obtained by providing a lithium-resistant reduction layer 20 between the electrode assembly 10 and the negative electrode 30 with respect to the lithium ion battery 100 of the first embodiment.

The lithium-resistant reduction layer 20 can use the above-described materials used for the second solid electrolyte 3 in the electrode assembly 10. That is, a material that conducts lithium ions and is amorphous (glassy or amorphous) at room temperature is preferable. For example, Li ₃ BO ₃ , Li ₃ BO ₃ —Li ₄ SiO ₄ , Li ₃ BO ₃ —Li ₃ PO ₄ , Li ₃ BO ₃ —Li ₂ SO ₄ , Li ₂ CO ₃ —Li ₃ BO ₃ , and other lithium composite oxides containing Li and B. Furthermore, it is preferable to use the same material for the lithium-resistant layer 20 and the second solid electrolyte 3. The thickness of the lithium-resistant layer 20 is preferably about 0.1 μm to 10 μm, but can be set to a desired value depending on material characteristics and the design of the lithium ion battery 200.

  As shown in FIG. 9, the manufacturing method of such a lithium ion battery 200 is the second as the other surface of the electrode assembly 10 formed by using the manufacturing method of the electrode assembly 10 of the first embodiment. A step of laminating and forming the lithium-resistant reduction layer 20 on the surface 10b on the sintered body 2 side is included. Examples of the method for forming the lithium-resistant reduction layer 20 include a so-called sol-gel method involving a hydrolysis reaction of an organometallic compound, a solution process such as an organometallic pyrolysis method, and an appropriate metal compound and gas atmosphere. CVD method using ALD, ALD method, green sheet method using slurry of solid electrolyte particles, screen printing method, aerosol deposition method, sputtering method using appropriate target and gas atmosphere, PLD method, melt and solution The flux method used can be used.

  In addition, the surface of the formed lithium-resistant reduction layer 20 on the negative electrode 30 side can be provided with an uneven structure such as a trench, a grating, or a pillar by combining various forming methods and processing methods as necessary. Further, the lithium-resistant reduction layer 20 is not limited to a single layer, and may have a multilayered structure, for example, an amorphous glass electrolyte layer is formed on the surface of a crystalline layer.

According to the second embodiment, in addition to the effects (1) to (3) of the first embodiment, the following effects can be obtained.
(4) Since the lithium-resistant reduction layer 20 is formed between the electrode assembly 10 and the negative electrode 30, the first sintered body 1 and the second sintered body 2 each made of crystalline particles are interposed. The current collector 41 (positive electrode) and the negative electrode 30 can be prevented from being electrically short-circuited. Furthermore, even if the lithium ion storage property of the negative electrode 30 is reduced and lithium metal is deposited due to repeated charge and discharge in the lithium ion battery 200, the dendritic tree that has been deposited from the negative electrode 30 side and developed to the electrode composite 10 side. It is possible to effectively prevent a positive / negative electrode short-circuit (dendritic short) due to the lithium metal. That is, the lithium ion battery 200 having high reliability quality can be provided or manufactured.

(Third embodiment)
<Other lithium ion batteries>
Next, the lithium ion battery of 3rd Embodiment is demonstrated with reference to FIG. FIG. 10 is a schematic cross-sectional view showing the structure of the lithium ion battery of the third embodiment. The lithium ion battery according to the third embodiment is different from the lithium ion battery 200 according to the second embodiment in the configuration (structure) of the electrode assembly 10. Therefore, the same components as those of the lithium ion battery 200 are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 10, the lithium ion battery 300 of the present embodiment includes a pair of current collectors 41 and 42, an electrode composite 10 </ b> B provided between the pair of current collectors 41 and 42, and lithium-resistant reduction. The layer 20 and the negative electrode 30 are included. Hereinafter, the electrode assembly 10B that is a characteristic part of the present embodiment will be described.

  The electrode composite 10B includes a porous first sintered body 1B formed by sintering a plurality of positive electrode active material particles 1a, and a porous second sintered body formed by sintering a plurality of first solid electrolyte particles 2a. The sintered body 2 and the second solid electrolyte 3 are combined.

  In the first sintered body 1B, a first solid electrolyte 2b is formed on the surface of the positive electrode active material particles 1a. The first solid electrolyte 2b is formed using the same material as that constituting the first solid electrolyte particle 2a. In FIG. 10, the first solid electrolyte 2b is shown so as to cover all the surfaces of the positive electrode active material particles 1a, but actually, it does not cover all the surfaces of the positive electrode active material particles 1a. The first solid electrolyte 2b is formed on at least a part of the surface of the plurality of sintered positive electrode active material particles 1a excluding a portion where the positive electrode active material particles 1a are in contact with each other. By adopting such a configuration, the area where the first solid electrolyte 2b, which has better ion conductivity than the second solid electrolyte 3, and the positive electrode active material particles 1a are in contact with each other is substantially increased as compared with the electrode assembly 10. I have to. This improves the conductivity of lithium ions at the interface between the first sintered body 1B and the second solid electrolyte 3.

<Manufacturing method of other electrode composite>
Next, a method for manufacturing the electrode assembly 10B will be described with reference to FIGS. FIG. 11 is a flowchart showing a method for manufacturing an electrode assembly according to the third embodiment, and FIGS. 12 to 15 are schematic cross-sectional views showing a method for manufacturing the electrode assembly according to the third embodiment.

  As shown in FIG. 11, the manufacturing method of the electrode assembly 10B of this embodiment includes a first sintered body forming step (step S11), a first solid electrolyte forming step (step S12), and a second sintered body. A formation process (step S13), a second solid electrolyte filling process (step S14), and a composite process (step S15) are provided. Note that Step S1 and Step S11 of the present embodiment are basically the same as the method for manufacturing the electrode assembly 10 of the first embodiment. Step S2 and step S13 of this embodiment, step S3 and step S14 of this embodiment, and step S4 and step S15 of this embodiment are all basically the same. Step S12 includes the fifth and sixth steps of the present invention.

  In the first sintered body forming step of step S11, a porous first sintered body 1 formed by sintering a plurality of positive electrode active material particles 1a is formed in the same manner as in step S1 of the first embodiment. . Then, the process proceeds to step S12.

  In the first solid electrolyte formation step of step S12, first, a precursor solution 2p (see FIG. 12) of the first solid electrolyte 2b is prepared. The precursor solution 2p of the first solid electrolyte 2b includes at least a precursor of the first solid electrolyte 2b and a solvent. Examples of the precursor solution 2p include the following examples (A) to (C).

(A) A composition comprising a metal atom in a proportion according to the composition of the first solid electrolyte 2b and having a salt which becomes the first solid electrolyte 2b by oxidation.
(B) The composition which has a metal alkoxide which contains a metal atom in the ratio according to the composition of the 1st solid electrolyte 2b.
(C) A dispersion in which fine particles of the first solid electrolyte 2b or fine particle sol containing metal atoms in a proportion according to the composition of the first solid electrolyte 2b are dispersed in a solvent or (A) or (B).
In addition, the metal complex is contained in the salt contained in (A). (B) is used when the first solid electrolyte 2b is formed by using a so-called sol-gel method.

  The solvent contained in the precursor solution 2p is appropriately selected from water, an aqueous solvent, or a non-aqueous organic solvent depending on the precursor contained in the above (A) to (C).

  In the present embodiment, LLZrNbO is used as the first solid electrolyte 2b that exhibits higher ionic conductivity than the second solid electrolyte 3. Crystal particles of LLZrNbO are dispersed in a solvent and used as the precursor solution 2p. The average particle diameter (D50) of LLZrNbO used here is, for example, 30 nm to 10 μm.

  Next, as shown in FIG. 12, the prepared precursor solution 2p is applied to the first sintered body 1 obtained in step S11. It is preferable to apply the precursor solution 2p by using the quantitative discharger 50 so that the application amount determined in consideration of the bulk density of the first sintered body 1 can be applied without waste. The applied precursor solution 2p soaks into the porous first sintered body 1. Then, the solvent component is removed from the precursor solution 2p soaked in the first sintered body 1 by performing heat treatment. Further, by firing, as shown in FIG. 13, the first solid electrolyte 2b is deposited and formed on a part of the surface of the positive electrode active material particle 1a.

  The removal of the solvent is performed by using at least one generally known method such as heating, decompression, and air blowing. The firing in this case is performed in an air atmosphere at a temperature lower than the firing temperature when forming the first sintered body 1. The firing temperature in this case is, for example, a temperature range of 500 ° C. or higher and 900 ° C. or lower. If the firing temperature is too high, an electrochemically inactive by-product may be generated due to a solid-phase reaction at the interface between the positive electrode active material particles 1a and the first solid electrolyte 2b. Such by-products adversely affect the characteristics of the lithium ion battery 300. On the other hand, if the firing temperature is too low, the crystallinity of the first solid electrolyte 2b is poor, and sufficient ion conductivity may not be obtained. Then, the process proceeds to step S13.

  In the second sintered body forming step of step S13, a porous second sintered body 2 formed by sintering a plurality of first solid electrolyte particles 2a is formed in the same manner as in step S2 of the first embodiment. To do. Then, the process proceeds to step S14.

  In the second solid electrolyte filling step of step S14, as in step S3 of the first embodiment, first, pellets 3p of the second solid electrolyte 3 (see FIG. 14) are prepared. Subsequently, as shown in FIG. 14, the pellet 3p of the second solid electrolyte 3 is obtained by performing heat treatment with the pellet 3p sandwiched between the first sintered body 1B and the second sintered body 2. Melt. The melt of the pellet 3p soaks into the porous first sintered body 1B and second sintered body 2.

  The temperature in the heat treatment is preferably a temperature equal to or higher than the melting point of the second solid electrolyte 3 and equal to or lower than 900 ° C., as in step S3 of the first embodiment. Also in this case, since LCBO is used as the second solid electrolyte 3, the temperature of the heat treatment was set to 700 ° C. higher than the melting point of LCBO (685 ° C.). Then, the process proceeds to step S15.

  In the composite process of step S15, the laminated body of the first sintered body 1B and the second sintered body 2 into which the melt of the second solid electrolyte 3 has been immersed is cooled. Thereby, the melt of the second solid electrolyte 3 filled in the laminate in which the first sintered body 1B and the second sintered body 2 are laminated is solidified, and as shown in FIG. An electrode assembly 10B in which the body 1B, the second sintered body 2, and the second solid electrolyte 3 were combined was obtained.

  According to the third embodiment, the first sintered body 1B is formed on a part of the surface of the sintered positive electrode active material particles 1a, and has an ion conductivity superior to that of the second solid electrolyte 3. Since the first solid electrolyte 2b is included, the positive electrode active material particles 1a located away from the negative electrode 30 side also contribute to the battery reaction. Therefore, by using the electrode assembly 10B, it is possible to provide or manufacture the lithium ion battery 300 having more excellent battery characteristics (charge / discharge characteristics).

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The method for producing the electrode composite and the battery to which the electrode composite is applied are also included in the technical scope of the present invention. Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

  (Modification 1) In the lithium ion battery 100 of the first embodiment, instead of the electrode assembly 10, the electrode assembly 10B shown in the third embodiment may be used.

  (Modification 2) In the lithium ion batteries 100, 200, 300 of the above embodiment, the pair of current collectors 41, 42 is not essential, and one of the pair of current collectors 41, 42 is formed. There may be. For example, if the current collector 41 is made of Au (gold) and lithium ion batteries are stacked and used, the current collector 42 can be dispensed with.

  (Modification 3) In the method for manufacturing the electrode assembly 10 of the first embodiment, the step of forming the second sintered body 2 (step S2) is performed after the step of forming the first sintered body 1 (step S1). It is not limited to being implemented. Step S1 and step S2 may be performed in parallel. The same applies to the method for manufacturing the electrode assembly 10B of the third embodiment.

  DESCRIPTION OF SYMBOLS 1,1B ... 1st sintered compact, 1a ... Positive electrode active material particle as an active material, 2 ... 2nd sintered compact, 2a ... 1st solid electrolyte particle as 1st solid electrolyte, 3 ... 2nd solid electrolyte, DESCRIPTION OF SYMBOLS 10,10B ... Electrode composite, 20 ... Lithium-resistant reduction layer, 30 ... Negative electrode, 41, 42 ... Current collector, 100, 200, 300 ... Lithium ion battery as a battery.

Claims (18)

A porous first sintered body containing an active material;
A porous second sintered body containing a first solid electrolyte;
An electrode composite comprising a second solid electrolyte filled in a laminate of the first sintered body and the second sintered body.   2. The electrode composite according to claim 1, wherein the porosity of the first sintered body is equal to or larger than the porosity of the second sintered body.   3. The electrode composite according to claim 1, wherein a thickness of the first sintered body is the same as or thicker than a thickness of the second sintered body.   4. The electrode assembly according to claim 1, wherein the first sintered body includes the first solid electrolyte formed on a surface of the active material. 5.   5. The electrode assembly according to claim 1, wherein the active material is a positive electrode active material made of a lithium composite metal compound. 6. The active material is an oxide containing Li and Co,
The first solid electrolyte is an oxide containing Li, La, Zr,
The electrode composite according to claim 5, wherein the second solid electrolyte is an oxide containing Li and B.   A battery comprising the electrode assembly according to any one of claims 1 to 6. A first step of forming a porous first sintered body using particles of an active material;
A second step of forming a porous second sintered body using the particles of the first solid electrolyte;
A third step of impregnating a laminate of the first sintered body and the second sintered body with a melt of the second solid electrolyte;
And a fourth step of cooling the laminate impregnated with the melt of the second solid electrolyte.   The method for producing an electrode assembly according to claim 8, wherein the melting point of the second solid electrolyte is lower than the melting points of the active material and the first solid electrolyte.   10. The mixture according to claim 8, wherein in the third step, a mixture containing the second solid electrolyte sandwiched between the first sintered body and the second sintered body is melted. A method for producing an electrode composite.   The method for producing an electrode assembly according to any one of claims 8 to 10, wherein the active material is a positive electrode active material made of a lithium composite metal compound. The active material is an oxide containing Li and Co,
The first solid electrolyte is an oxide containing Li, La, Zr,
The second solid electrolyte is an oxide containing Li and B,
The method for producing an electrode assembly according to claim 11, wherein, in the third step, the second solid electrolyte is melted at a temperature of 700 ° C or higher and lower than 900 ° C. The first step includes a fifth step of impregnating the first sintered body with a solution containing the first solid electrolyte and a solvent;
A sixth step of heating the first sintered body impregnated with the solution to remove the solvent, The electrode assembly according to any one of claims 8 to 12, Production method.   14. The method according to claim 8, wherein at least the third step among the first step, the second step, and the third step is performed in an atmosphere from which moisture is removed. The method for producing an electrode assembly according to one item. The second solid electrolyte is an oxide containing Li, C, and B,
The method for producing an electrode assembly according to claim 14, wherein the atmosphere in the third step contains carbon dioxide gas.   A method for producing a battery, comprising a step of forming a current collector on at least one surface of the electrode assembly according to any one of claims 1 to 6. The active material is a positive electrode active material made of a lithium composite metal compound,
The battery manufacturing method according to claim 16, further comprising a step of forming a negative electrode on the other surface of the electrode composite.   The battery manufacturing method according to claim 17, further comprising a step of forming a lithium-resistant reduction layer between the other surface of the electrode composite and the negative electrode.

Images