JP2014154238A - Method of producing composite and method of producing lithium battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a composite in which the process can be shortened, and to provide a method of producing a high productivity lithium battery including such a method.SOLUTION: A method of producing a composite includes a step for arranging a precursor on the surface by coating the surface of a molding including the interior of pores of a porous molding with a solution having a precursor containing a first complex where a first ligand is coordinated with a first metal atom, and a second complex where a second ligand having a molecular weight smaller than that of the first ligand is coordinated with a second metal atom, and a step for obtaining a metal double oxide containing a first metal atom and a second metal atom by heat treating the precursor.

Description

  The present invention relates to a method for producing a composite and a method for producing a lithium battery.

  Lithium batteries (including primary batteries and secondary batteries) are used as a power source for many electronic devices including portable information devices. The lithium battery includes a positive electrode, a negative electrode, and an electrolyte layer that is disposed between these layers and mediates conduction of lithium ions.

  In recent years, all-solid-state lithium batteries that use a solid electrolyte as a material for forming an electrolyte layer have been proposed as lithium batteries that achieve both high energy density and safety. For example, in Patent Documents 1 and 2, a solution in which a forming material of a solid electrolyte or a positive electrode active material is dissolved is used, and the forming material is deposited at a desired position by heating the solution to remove the solvent. By disposing, a solid electrolyte or a positive electrode active material is formed.

JP 2011-238523 A JP 2010-218686 A

  In the method described in the above-mentioned patent document, it is necessary to repeatedly perform the operation of depositing the forming material from the solution and forming the solid electrolyte and the positive electrode active material in order to arrange the required amount of the solid electrolyte and the positive electrode active material at a predetermined position. is there. Such repeated operation is a factor that increases the takt time in the manufacturing process. Therefore, there is a method that enables the required amount of the solid electrolyte and the positive electrode active material to be arranged and the process can be shortened by repeating the operation as few times as possible. It was sought after.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the manufacturing method of the composite_body | complex which can shorten a process. Another object of the present invention is to provide a method for manufacturing a lithium battery with high productivity including such a method.

  In order to solve the above problems, one embodiment of the present invention includes a first complex in which a first ligand is coordinated to a first metal atom, and a second ligand having a molecular weight smaller than that of the first ligand. Is applied to the surface of the molded body including the inside of the pores of the porous molded body, and the precursor is applied to the surface. And a step of obtaining a metal double oxide containing the first metal atom and the second metal atom by heat-treating the precursor. .

  According to this method, in a metal complex, if the ligand is small, the reactivity is relatively high, and thus precipitation is likely to occur in a solution in which two kinds of metal complexes are mixed. However, according to this method, since the solution includes the first complex including the first ligand having a molecular weight higher than that of the second ligand, the first ligand having a relatively large molecular weight is stable in the solution. It contributes to the property, and the occurrence of precipitation can be suppressed.

  Moreover, since the precursor is applied as a solution, the precursor can be favorably disposed inside the pores of the molded body, and a composite in which the metal double oxide is suitably filled in the pores can be obtained. Can do.

  Furthermore, since the precursor contains a second ligand having a molecular weight smaller than that of the first ligand, before and after heat treatment of the precursor, compared to the case where the precursor has only the first ligand. The volumetric shrinkage at is reduced. Therefore, in order to obtain a necessary amount of the metal double oxide, the number of repeated operations for laminating the precursor on the surface of the molded body can be reduced.

  From the above, according to this method, the manufacturing process of the composite can be shortened.

In one aspect of the present invention, the arranging step may be a manufacturing method including filling the solution into the pores while heating the solution.
According to this method, since the viscosity of the solution is reduced by heating, the solution easily penetrates into the pores even in a concentrated solution with many solute components, and the metal double oxide is suitably filled in the pores. The obtained complex can be obtained by a small number of repeated operations.

In one aspect of the present invention, the arranging step includes arranging the solution on the surface of the molded body in a first environment reduced in pressure from atmospheric pressure, and the molded body on which the solution is arranged. May be disposed in a second environment having a pressure higher than that in the first environment to fill the pores with the solution.
According to this method, due to the differential pressure between the first environment and the second environment, the solution easily penetrates into the pores in the molded body placed in the second environment. Therefore, the solution easily penetrates into the pores, and a complex filled with the metal double oxide can be easily obtained even inside the pores.

In one aspect of the present invention, the solution may be a manufacturing method prepared by concentrating a low-concentration solution prepared in advance at a lower concentration than the solution.
Even if a high-concentration solution is directly prepared, even if precipitation occurs, the solution is once reduced to a low-concentration solution and gradually concentrated to prepare a high-concentration solution that does not cause precipitation. It is possible. Therefore, according to this method, it is possible to arrange a required amount of precursor on the surface of the molded body with a small number of operations by using a high-concentration solution.

In one embodiment of the present invention, a first complex in which a first ligand is coordinated to a first metal atom, and a second ligand having a molecular weight smaller than that of the first ligand are the second metal atom. A solution containing a precursor having a coordinated second complex is disposed on the surface of the active material molded body including the inside of the pores of the porous active material molded body and heat-treated, and the first metal Lithium comprising: a step of forming a solid electrolyte layer having a metal double oxide containing atoms and the second metal atom; and a step of bonding a current collector to the active material molded body exposed from the solid electrolyte layer A method for manufacturing a battery is provided.
According to this method, since the solution includes the first complex containing the first ligand having a molecular weight higher than that of the second ligand, the first ligand having a relatively large molecular weight can improve the stability of the solution. This contributes to the suppression of precipitation. Further, by using such a stable solution, the precursor can be effectively disposed even inside the pores, and a solid electrolyte layer can be formed. Furthermore, since the precursor includes a second ligand having a small molecular weight, the precursor is formed on the surface of the active material molded body in order to obtain a necessary amount of the solid electrolyte layer as compared with the case where the precursor has only the first ligand. The number of repeated operations for laminating the body can be reduced, and the process can be shortened.

In one aspect of the present invention, the step of forming the solid electrolyte layer may be a manufacturing method in which the solution is disposed on the surface of the active material molded body while heating the solution.
According to this method, since the viscosity of the solution is reduced by heating, the solution can easily penetrate into the pores, and the solid electrolyte layer can be suitably filled even inside the pores of the active material molded body. . Therefore, a high output lithium battery can be easily manufactured.

In one aspect of the present invention, the step of forming the solid electrolyte layer includes disposing the solution on the surface of the active material molded body in a first environment reduced in pressure from atmospheric pressure, and The active material molded body may be disposed in a second environment having a pressure higher than that in the first environment, and the solution may be filled in the pores. .
According to this method, due to the differential pressure between the first environment and the second environment, the solution easily penetrates into the pores in the active material molded body placed in the second environment. Therefore, the solution easily penetrates into the pores, and the solid electrolyte layer can be suitably filled even inside the pores, and a high-power lithium battery can be easily manufactured.

In one aspect of the present invention, the solution may be a manufacturing method prepared by concentrating a low-concentration solution prepared in advance at a lower concentration than the solution.
Even if a high-concentration solution is directly prepared, even if precipitation occurs, the solution is once reduced to a low-concentration solution and gradually concentrated to prepare a high-concentration solution that does not cause precipitation. It is possible. Therefore, according to this method, by using a high-concentration solution, it becomes possible to arrange the required amount of precursor on the surface of the active material molded body with a small number of operations, and easily produce a high-power lithium battery. can do.

It is principal part side sectional drawing which shows the composite_body | complex manufactured with the manufacturing method of this embodiment. It is process drawing which shows the manufacturing method of the lithium battery of this embodiment. It is process drawing which shows the manufacturing method of the lithium battery of this embodiment. It is process drawing which shows the manufacturing method of the lithium battery of this embodiment. It is process drawing which shows the manufacturing method of the lithium battery of this embodiment. It is a sectional side view which shows the modification of the electrode complex manufactured with the manufacturing method of this embodiment. It is a sectional side view which shows the modification of the electrode complex manufactured with the manufacturing method of this embodiment. It is process drawing which shows the modification of the manufacturing method of the electrode composite_body | complex of this embodiment. It is principal part side sectional drawing which shows the lithium battery of this embodiment. It is a TG-DTA chart which shows the result of an Example. It is a TG-DTA chart which shows the result of an Example. It is a TG-DTA chart which shows the result of an Example. It is a TG-DTA chart which shows the result of an Example.

[Complex]
FIG. 1 is a cross-sectional side view of an essential part showing a composite manufactured by the composite manufacturing method of the present embodiment. In all the drawings below, the dimensions and ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

  The composite 4 of the present embodiment includes an active material molded body 2 (molded body) and a solid electrolyte layer 3. A configuration in which the current collector 1 is further provided on one surface of the composite 4 is referred to as an electrode composite 10. The electrode assembly 10 is used for a lithium battery as will be described later. Hereinafter, manufacturing the composite 4 used in the lithium battery by the composite manufacturing method of the present embodiment will be described with reference to the configuration of the electrode composite 10.

  The current collector 1 is provided in contact with the active material molded body 2 exposed from the solid electrolyte layer 3 on one surface 4 a of the composite 4. As a material for forming the current collector 1, copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), One metal selected from the group consisting of germanium (Ge), indium (In), gold (Au), platinum (Pt), silver (Ag) and palladium (Pd), or selected from this group Examples include alloys containing two or more metal elements.

  As the shape of the current collector 1, a plate shape, a foil shape, a net shape, or the like can be adopted. The surface of the current collector 1 may be smooth or uneven.

  The active material molded body 2 is a porous molded body using an inorganic electrode active material as a forming material. The plurality of pores of the active material molded body 2 communicate with each other in a mesh form inside the active material molded body 2.

The active material molded body 2 has different formation materials depending on whether the current collector 1 is used on the positive electrode side or the negative electrode side in a lithium battery.
When the current collector 1 is used on the positive electrode side, a lithium double oxide that is generally known as a positive electrode active material can be used as a material for forming the active material molded body 2.

  In the present specification, the “lithium double oxide” refers to an oxide that always contains lithium and contains two or more kinds of metal ions as a whole and in which the presence of oxo acid ions is not recognized.

Examples of such lithium double oxides 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, LiFeF 3, Li 2 FeSiO 4, Li 2 MnSiO 4 , and the like. In this specification, solid solutions in which some atoms in the crystal of these lithium double oxides are substituted with other transition metals, typical metals, alkali metals, alkali rare earths, lanthanoids, chalcogenides, halogens, etc. These solid solutions can be used as the positive electrode active material.

When the current collector 1 is used on the negative electrode side, a lithium composite oxide such as Li ₄ Ti ₅ O ₁₂ or Li ₂ Ti ₃ O ₇ is used as a negative electrode active material as a material for forming the active material molded body 2. Can do.

  The active material molded body 2 preferably has a porosity of 10% to 50%. When the active material molded body 2 has such a porosity, the surface area in the pores of the active material molded body 2 is increased, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 is easily expanded. It becomes easy to increase the capacity of the lithium battery using the electrode assembly 10.

The porosity is obtained by (1) the volume (apparent volume) of the active material molded body 2 including pores obtained from the outer dimensions of the active material molded body 2, (2) the mass of the active material molded body 2, ( 3) From the density of the active material constituting the active material molded body 2, it can be measured based on the following formula (I).

  As will be described in detail later, the porosity of the active material molded body 2 can be controlled by using a pore former in the step of forming the active material molded body 2.

The resistivity of the active material molded body 2 is preferably 700 Ω / cm or less. When the active material molded body 2 has such a resistivity, a sufficient output can be obtained when a lithium battery is formed using the electrode composite 10.
The resistivity can be measured by attaching a copper foil used as an electrode to the surface of the active material molded body and performing DC polarization measurement.

  The solid electrolyte layer 3 uses the solid electrolyte as a forming material, and is provided in contact with the surface of the active material molded body 2 including the inside of the pores of the active material molded body 2.

The solid electrolyte, for _{example, 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 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, LiF-Al 2 O 3, LiBr-Al 2 _{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-LiOH, 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 Examples thereof include oxides such as _4- LiMoO ₄ , Li ₃ PO ₄ -Li ₄ SiO ₄ , LiSiO ₄ -Li ₄ ZrO ₄ , sulfides, halides, and nitrides. These solid electrolytes may be crystalline or amorphous. Further, in the present specification, solid solutions in which some atoms of these compositions are substituted with other transition metals, typical metals, alkali metals, alkali rare earths, lanthanoids, chalcogenides, halogens, and the like may be used as solid electrolytes. it can.

The ionic conductivity of the solid electrolyte layer 3 is preferably 1 × 10 ⁻⁵ S / cm or more. Since the solid electrolyte layer 3 has such ionic conductivity, ions contained in the solid electrolyte layer 3 at a position away from the surface of the active material molded body 2 reach the surface of the active material molded body 2, and the active material It becomes possible to contribute to the battery reaction in the molded body 2. Therefore, the utilization factor of the active material in the active material molded body 2 can be improved and the capacity can be increased. At this time, when the ionic conductivity is less than 1 × 10 ⁻⁵ S / cm, when the electrode composite is used for a lithium battery, only the active material near the surface layer on the surface facing the counter electrode in the active material molded body 2 is used. It does not contribute to the reaction, and the capacity may be reduced.

The “ionic conductivity of the solid electrolyte layer 3” refers to the “bulk conductivity” that is the conductivity of the inorganic electrolyte itself that constitutes the solid electrolyte layer 3, and the crystal in the case where the inorganic electrolyte is crystalline. It refers to the “total ionic conductivity” that is the sum of the “grain boundary ionic conductivity” that is the conductivity between particles.
The ionic conductivity of the solid electrolyte layer 3 is obtained by pressing a solid electrolyte powder into a tablet shape at 624 MPa, sintering it at 700 ° C. for 8 hours in an air atmosphere, forming a platinum electrode by sputtering, and performing an AC impedance method. It can be measured by carrying out.

  In the composite 4, when the direction away from the surface of the current collector 1 in the normal direction is the upward direction, the upper surface 3 a of the solid electrolyte layer 3 is above the upper end position 2 a of the active material molded body 2. positioned. That is, the solid electrolyte layer 3 is formed up to the upper side of the upper end position 2 a of the active material molded body 2. Thereby, when producing the lithium battery which has an electrode on the surface 3a and has the electrode composite 10, the electrode provided on the surface 3a and the current collector 1 are not connected by the active material molded body 2, Short circuit can be prevented.

  As will be described in detail later, one surface 4 a of the composite 4 is a polished surface that is polished during manufacture, and the active material molded body 2 is exposed from the solid electrolyte layer 3.

  The electrode assembly 10 of the present embodiment includes an organic substance such as a binder that joins the active materials together and a conductive additive for ensuring the conductivity of the active material molded body 2 when the active material molded body 2 is molded. It is molded without being used, and is almost composed only of inorganic substances. Specifically, in the electrode assembly 10 of the present embodiment, the mass reduction rate when the composite 4 (the active material molded body 2 and the solid electrolyte layer 3) is heated at 400 ° C. for 30 minutes is 5% by mass or less. It has become. The mass reduction rate is preferably 3% by mass or less, more preferably 1% by mass or less, and particularly preferably no mass reduction is observed or an error range.

  Since the composite 4 has such a mass reduction rate, a substance such as a solvent or adsorbed water that evaporates under a predetermined heating condition, or an organic substance that is burned or oxidized under a predetermined heating condition is vaporized in the composite 4. Therefore, only 5% by mass or less is included with respect to the entire configuration.

  The mass reduction rate of the composite 4 is determined by heating the composite 4 under a predetermined heating condition using a differential thermal-thermogravimetric simultaneous measurement apparatus (TG-DTA), thereby heating the composite 4 after heating under the predetermined heating condition. Can be calculated from the ratio of the mass before heating to the mass after heating.

In the electrode assembly 10 of the present embodiment, in the active material molded body 2, a plurality of pores communicate with each other in a network shape, and the solid portion of the active material molded body 2 also forms a network structure. For example, LiCoO ₂ that is a positive electrode active material is known to have anisotropy in the electronic conductivity of crystals, but when an active material molded body is formed using LiCoO ₂ as a forming material, pores are mechanically formed. In a configuration in which pores are provided extending in a specific direction as formed by processing, depending on the direction showing the electron conductivity of the crystal, it may be difficult to conduct electrons inside. However, when the pores are connected in a network shape like the active material molded body 2 and the solid portion of the active material molded body 2 has a network structure, the anisotropy of the electron conductivity or ionic conductivity of the crystal. Regardless, an electrochemically lubricious continuous surface can be formed. Therefore, good electronic conduction can be ensured regardless of the type of active material used.

  In addition, in the electrode assembly 10 of the present embodiment, since the composite 4 has the above-described configuration, the amount of the binder and the conductive assistant contained in the composite 4 is suppressed, and the binder and the conductive assistant are suppressed. Compared with the case where an agent is used, the capacity density per unit volume of the electrode assembly 10 is improved.

  In the electrode assembly 10 of the present embodiment, the solid electrolyte layer 3 is also in contact with the surfaces of the pores of the porous active material molded body 2. Therefore, the contact area between the active material molded body 2 and the solid electrolyte layer 3 is larger than when the active material molded body 2 is not a porous body or when the solid electrolyte layer 3 is not formed in the pores. , Interface impedance can be reduced. Therefore, good charge transfer is possible at the interface between the active material molded body 2 and the solid electrolyte layer 3.

  In the electrode assembly 10 of the present embodiment, the current collector 1 is in contact with the active material molded body 2 exposed on one surface of the composite 4, whereas the solid electrolyte layer 3 is porous. It penetrates into the pores of the active material molded body 2 and is in contact with the surface of the active material molded body 2 other than the surface including the inside of the pores and contacting the current collector 1. In the electrode assembly 10 having such a structure, the contact area between the active material molded body 2 and the solid electrolyte layer 3 (the first contact area) rather than the contact area between the current collector 1 and the active material molded body 2 (first contact area). It is clear that the second contact area) is larger.

  If the electrode composite has the same configuration as the first contact area and the second contact area, the interface between the current collector 1 and the active material molded body 2 is closer to the active material molded body 2 and the solid electrolyte layer. Since the charge transfer is easier than that of the interface with 3, the interface between the active material molded body 2 and the solid electrolyte layer 3 becomes a bottleneck of charge transfer. Therefore, good charge transfer is inhibited as the whole electrode assembly.

  However, in the electrode assembly 10 of the present embodiment, the second contact area is larger than the first contact area, so that the bottleneck described above can be easily eliminated, and the electrode assembly as a whole has good charge transfer. It becomes possible.

  From these things, the electrode assembly 10 manufactured by the manufacturing method of this embodiment can improve the capacity | capacitance of the lithium battery using the electrode assembly 10, and can be set as high output.

[Composite manufacturing method, lithium battery manufacturing method]
Next, the manufacturing method of the composite body of this embodiment and the manufacturing method of a lithium battery are demonstrated using FIGS. 2-5 is process drawing which shows the manufacturing method of the lithium battery of this embodiment. Moreover, FIG. 3 is process drawing which shows the manufacturing method of the composite_body | complex of this embodiment.

  First, as shown in FIG. 2, a forming material containing particulate lithium double oxide (hereinafter referred to as active material particles 2X) is compressed and formed using a forming die F (FIG. 2 (a)). The active material molded body 2 is obtained by heat treatment (FIG. 2B).

By heat treatment, the growth of grain boundaries in the active material particles 2X and the sintering between the active material particles 2X proceed, so that the resulting active material molded body 2 can easily maintain its shape, and the active material molded body 2 The amount of binder added can be reduced. Moreover, since a bond is formed between the active material particles 2X by sintering and an electron transfer path between the active material particles 2X is formed, the amount of the conductive additive added can also be suppressed. LiCoO ₂ can be suitably used as a material for forming the active material particles 2X.

  Further, the obtained active material molded body 2 has a plurality of pores of the active material molded body 2 communicated with each other inside the active material molded body 2 in a mesh shape.

The average particle diameter of the active material particles 2X is preferably 300 nm or more and 5 μm or less. When an active material having such an average particle diameter is used, the resulting active material molded body 2 has a porosity of 10% to 40%. As a result, the surface area in the pores of the active material molded body 2 can be increased, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 can be easily expanded, and the lithium battery using the electrode composite 10 can have a high capacity. It becomes easy.
The average particle diameter of the active material particles 2X is determined by dispersing the active material particles 2X in n-octanol so as to have a concentration in the range of 0.1% by mass to 10% by mass, and then using a light scattering particle size distribution analyzer (Nikkiso). It can be measured by determining the median diameter using Nanotrac UPA-EX250, manufactured by the company.

  If the average particle diameter of the active material particles 2X is less than 300 nm, the radius of the pores of the formed active material molded product tends to be very small with a few tens of nm, and an inorganic solid is formed inside the pores in the process described later. It becomes difficult to infiltrate a liquid containing an electrolyte precursor. As a result, it becomes difficult to form the solid electrolyte layer 3 in contact with the surface inside the pores.

  When the average particle diameter of the active material particles 2X exceeds 5 μm, the specific surface area, which is the surface area per unit mass of the formed active material molded body, is reduced, and the contact area between the active material molded body 2 and the solid electrolyte layer 3 is reduced. Get smaller. Therefore, when a lithium battery is formed using the obtained electrode assembly 10, a sufficient output cannot be obtained. Further, since the ion diffusion distance from the inside of the active material particle 2X to the solid electrolyte layer 3 becomes long, the lithium double oxide near the center in the active material particle 2X hardly contributes to the function of the battery.

  The average particle diameter of the active material particles 2X is more preferably 450 nm or more and 3 μm or less, and further preferably 500 nm or more and 1 μm or less.

  In the forming material to be used, an organic polymer compound such as polyvinylidene fluoride (PVdF) or polyvinyl alcohol (PVA) may be added to the active material particles 2X as a binder. These binders are combusted or oxidized in the heat treatment of this step, and the amount is reduced or disappears.

  The forming material to be used may be added with a particulate pore former using a polymer or carbon powder as a forming material for pores at the time of compacting. By mixing these pore formers, the porosity of the active material molded body can be controlled. Such a pore former is decomposed and removed by combustion or oxidation during heat treatment, and the amount of the resulting active material molded body is reduced.

  The average particle diameter of the pore former is preferably 0.5 μm to 10 μm.

  It is preferable that the pore former includes particles (first particles) whose material is a deliquescent material. Since the water generated around the first particles due to the deliquescent of the first particles functions as a binder that joins the particulate lithium double oxide, the process until the particulate lithium double oxide is compression-molded and heat-treated. During this time, the shape can be maintained. Therefore, an active material molded body can be obtained without adding another binder or while reducing the amount of the binder added, and a high-capacity electrode composite can be easily obtained.

  As such 1st particle | grains, the particle | grains which use polyacrylic acid as a forming material can be mentioned.

  Moreover, it is preferable that the pore former further includes particles (second particles) whose material is a material having no deliquescence. The pore former containing such second particles is easy to handle. Also, if the pore former has deliquescence, the porosity of the active material molded body may deviate from a desired set value depending on the amount of moisture around the pore former, but it does not deliquesce as a pore former. By including the second particles at the same time, it is possible to suppress the gap deviation.

  The heat treatment in this step is performed at a processing temperature of 800 ° C. or higher and lower than the melting point of the lithium double oxide used. Thereby, the active material particles 2 </ b> X are sintered to form an integrated molded body. By performing the heat treatment in such a temperature range, the resistivity of the obtained active material molded body 2 can be set to 700 Ω / cm or less without adding a conductive additive. Thereby, when a lithium battery is formed using the electrode assembly 10, sufficient output can be obtained.

  When the treatment temperature is less than 800 ° C., the sintering does not proceed sufficiently and the contact between the active material particles 2X is insufficient. Therefore, when the lithium battery is formed using the electrode assembly 10 obtained, The desired output cannot be obtained.

  When the processing temperature exceeds the melting point of the lithium double oxide, the lithium double oxide is melted, so that an active material molded body having a desired shape and physical properties cannot be obtained. Further, when such a high temperature treatment is performed, lithium ions are excessively volatilized from within the crystal of the lithium double oxide, so that the electronic conductivity of the lithium double oxide is reduced, and the capacity of the obtained electrode assembly 10 is also reduced. Resulting in.

  In the heat treatment in this step, the treatment temperature is more preferably 875 ° C. or more and 1000 ° C. or less, and further preferably 900 ° C. or more and 950 ° C. or less.

  Next, as shown in FIG. 3, a liquid 3X (solution) containing an inorganic solid electrolyte precursor is applied to the surface of the active material molded body 2 including the inside of the pores of the active material molded body (FIG. 3 ( a)) By firing, the solid electrolyte layer 3 is formed using the precursor as an inorganic solid electrolyte (FIG. 3B).

  The liquid 3X uses, as a precursor of the inorganic solid electrolyte, a composition having a metal complex that contains the metal atoms of the inorganic solid electrolyte in a proportion according to the composition formula of the inorganic solid electrolyte and becomes an inorganic solid electrolyte by oxidation. In such a metal complex, a first complex in which a first ligand is coordinated to a first metal atom, and a second ligand having a molecular weight smaller than that of the first ligand are coordinated to a second metal atom. And the second complex.

For example, when Li _0.35 La _0.55 TiO ₃ is employed as the inorganic solid electrolyte, the precursor includes a metal complex containing Li atoms, a metal complex containing La atoms, and a metal complex containing Ti atoms (Li Atom) :( La atom) :( Ti atom) = 0.35: 0.55: 1 (molar ratio).

  In addition, as the ligand of the precursor metal complex, various commonly known ligands may be adopted if the solution containing the precursor is stable without precipitation at room temperature (25 ° C.). it can. Of the plurality of metal complexes contained in the precursor, which metal coordinated ligand has a smaller molecular weight than the ligand coordinated to other metal atoms (second ligand described above) Can be set as appropriate depending on the stability of the liquid when the solution containing the precursor is prepared.

  Specifically, citric acid (molecular weight: 192), L-malic acid (molecular weight: 134), and glycolic acid (molecular weight: 76) can be used as the ligand. Taking these three types as an example, when the precursor metal complex includes one having citric acid as a ligand, the metal complex is the first complex, citric acid is the first ligand described above, The metal atom coordinated with citric acid is the first metal atom described above. Moreover, the 2nd complex which is another metal complex contained in a precursor can employ | adopt L-malic acid or glycolic acid as a 2nd ligand. The metal atom to which L-malic acid or glycolic acid is coordinated is the above-mentioned second metal atom.

  The liquid 3X can be prepared by mixing a solution in which each metal complex of the precursor is dissolved. In a metal complex, if the ligand is small, the reactivity becomes relatively high. Therefore, when the solutions in which the metal complex is dissolved are mixed, precipitation is likely to occur. However, in the method of the present embodiment, since the solution includes the first complex including the first ligand having a molecular weight higher than that of the second ligand, the first ligand having a relatively large molecular weight is the solution. This contributes to the stability of the material and suppresses the occurrence of precipitation.

  In the method of the present embodiment, the solvent contained in the liquid 3X is removed after the liquid 3X is applied and before firing. For the removal of the solvent, a method known in the art such as heating, reduced pressure, and air blowing, or a method combining two or more types can be employed. Thereby, the precursor adheres to the surface of the active material molded body 2.

  However, in order to attach a desired amount of precursor to the surface of the active material molded body 2, it is necessary to repeatedly perform the operation of applying the liquid 3X and removing the solvent. However, many of the active materials constituting the active material molded body 2 are deteriorated by moisture or acid, and it is desirable to repeat the operations of applying the liquid 3X and removing the solvent as few times as possible.

  Therefore, in the method of the present embodiment, a high-concentration liquid material 3X is used, and many precursors can be arranged by applying the liquid material 3X once. When the desired liquid 3X has a high concentration, precipitation may occur during the preparation process, and it may be difficult to obtain a stable liquid 3X. In such a case, after preparing a solution having a lower concentration than the desired concentration (low concentration solution) as the concentration of the liquid 3X, the low concentration solution is gradually concentrated to thereby prevent precipitation and produce a high concentration solution. Can be prepared.

  The liquid 3X can be applied by various methods as long as the liquid 3X penetrates into the pores of the active material molded body 2. For example, it may be performed by dropping the liquid material 3X where the active material molded body 2 is placed, or by immersing the active material molded body 2 where the liquid material 3X is stored. Alternatively, the end of the active material molded body 2 may be brought into contact with the location where the liquid 3X is stored, and impregnation into the pores using capillary action. FIG. 3A shows a method of dropping the liquid 3X using the dispenser D.

  Moreover, when the liquid 3X has a high concentration, the viscosity is likely to increase, and the liquid 3X may not easily penetrate into the pores of the active material molded body 2. In such a case, by heating the liquid 3X to a temperature higher than room temperature, the viscosity of the liquid 3X can be lowered and the liquid 3X can easily penetrate into the pores.

  Further, in order to infiltrate the liquid body 3X into the pores of the active material molded body 2, the operation of placing the liquid body 3X shown in FIG. 3A on the surface of the active material molded body 2 is performed at atmospheric pressure (101.325 kPa). The active material molded body 2 in which the liquid 3X is disposed may be disposed in a second environment having a pressure higher than that in the first environment. For example, using a vacuum chamber, a reduced pressure environment (first environment) reduced from the atmospheric pressure is formed, and after applying the liquid 3X under reduced pressure in the vacuum chamber, the atmospheric pressure (first It is recommended to perform an operation for returning to (2 environment). If the pressure of the first environment is too low, the solvent contained in the liquid 3X will be evaporated rapidly and it will be difficult to apply the liquid 3X, so that the operation of applying the liquid 3X will not be impaired. To do.

  When such a method is employed, the liquid 3X is easily brought into the pores of the active material molded body 2 in the molded body disposed in the second environment due to the differential pressure between the first environment and the second environment. Can penetrate.

The precursor is baked at a temperature lower than the heat treatment for obtaining the above-described active material molded body 2 in an air atmosphere. The baking temperature is preferably in the temperature range of 300 ° C. to 700 ° C. By firing, an inorganic solid electrolyte is produced from the precursor, and the solid electrolyte layer 3 is formed. As a material for forming the solid electrolyte layer, Li _0.35 La _0.55 TiO ₃ can be suitably used.

By baking in such a temperature range, a solid-phase reaction occurs due to mutual diffusion of the elements constituting each at the interface between the active material molded body 2 and the solid electrolyte layer 3, and an electrochemically inactive byproduct. Can be suppressed. Further, the crystallinity of the inorganic solid electrolyte is improved, and the ionic conductivity of the solid electrolyte layer 3 can be improved. In addition, a portion to be sintered is generated at the interface between the active material molded body 2 and the solid electrolyte layer 3, and charge transfer at the interface is facilitated.
Thereby, the capacity | capacitance and output of a lithium battery using the electrode composite 10 improve.

  The firing may be performed by a single heat treatment, and the first heat treatment for depositing the precursor on the surface of the active material molded body 2 and the heating under the temperature condition of the first heat treatment temperature to 700 ° C. The second heat treatment may be performed separately. By firing by such stepwise heat treatment, the solid electrolyte layer 3 can be easily formed at a desired position.

  When the precursor is baked, the ligand contained in the precursor is burned out and removed as carbon dioxide or water, so that the volume of the precursor attached to the surface of the active material molded body 2 shrinks. Volume shrinkage can also be confirmed as a mass loss. Thereby, voids appear in the pores of the active material molded body 2 and the filling rate is lowered. In order to increase the filling rate, it is necessary to repeat the placement and firing of the precursor.

  On the other hand, in the method of this embodiment, the 1st complex which has a 1st ligand in a precursor as mentioned above, and the 2nd complex which has a 2nd ligand are included. Since the second ligand has a lower molecular weight than the first ligand, the volume shrinkage is smaller when the second ligand is burned out than when the first ligand is burned out. Therefore, when the second ligand is included in the ligand that the precursor has, the volume shrinkage before and after heat treatment of the precursor is small compared to the case where the precursor has only the first ligand. Become. Therefore, in order to obtain a required amount of the metal double oxide, the number of repeated operations for laminating the precursor on the surface of the molded body can be reduced, and the process can be shortened.

In this way, the liquid electrolyte 3X having fluidity is applied to form the solid electrolyte layer 3, so that the solid electrolyte can be satisfactorily formed also on the inner surfaces of the pores of the fine active material molded body 2. It becomes possible. Therefore, in the composite 4, the contact area between the active material molded body 2 and the solid electrolyte layer 3 can be easily increased, the current density at the interface between the active material molded body 2 and the solid electrolyte layer 3 is reduced, and the composite 4 When it is used for a lithium battery, it becomes easy to obtain a large output.
The composite 4 can be manufactured as described above.

  Next, as shown in FIG. 4, the current collector 1 is joined to the active material molded body 2 exposed on one surface of the composite body 4 having the active material molded body 2 and the solid electrolyte layer 3, whereby the electrode composite 10. Manufacturing. In the present embodiment, after polishing one surface of the composite 4 (FIG. 4A), the current collector 1 is formed on one surface 4a (polishing surface) of the composite 4 (FIG. 4B).

  Prior to the bonding of the current collector 1, the active material molded body 2 is surely exposed on the first surface 4 a of the composite 4 by polishing the one surface 4 a of the composite 4, so that the current collector 1 and the active material molded body 2 are exposed. Can be reliably joined.

  Note that when the composite 4 is formed, the active material molded body 2 may be exposed on the surface in contact with the mounting surface of the composite 4. In this case, the current collector 1 and the active material molded body 2 can be joined without polishing the composite 4.

The current collector 1 may be joined by joining a current collector formed as a separate body to the one surface 4 a of the composite 4, and the material for forming the current collector 1 described above on the one surface 4 a of the composite 4. The current collector 1 may be formed on one surface 4 a of the composite 4 by forming a film. As a film forming method, a conventionally known physical vapor deposition method (PVD) or chemical vapor deposition method (CVD) can be employed.
In the manufacturing method of the present embodiment, the target electrode assembly 10 is manufactured in this way.

  According to the method for manufacturing an electrode assembly having the above configuration, an electrode assembly that can be a high-power and high-capacity lithium battery can be easily manufactured.

  Next, as shown in FIG. 5, the negative electrode 20 is bonded to the surface 3 a of the obtained electrode assembly 10 to form the lithium battery 100. That is, in the lithium battery 100, the active material molded body 2 is used as a positive electrode active material.

As a material of the negative electrode 20, for example, metallic lithium or metallic indium can be used. The negative electrode 20 may be formed as a separate body, and may be pressure-bonded to the electrode composite 10, and the electrode composite may be formed by using a commonly known physical vapor deposition method such as sputtering or vapor deposition of metal lithium or metal indium. It is good also as forming directly on the surface 3a of 10.
The lithium battery 100 can be manufactured as described above.

  According to the manufacturing method of the composite body 4 as described above, the number of repeated operations for laminating the precursor on the surface of the active material molded body 2 can be reduced, and the process can be shortened.

  Moreover, according to the manufacturing method of the above lithium battery 100, it can be set as the manufacturing method of a lithium battery with high productivity, including the manufacturing method of the above-mentioned composite in part.

(Modification 1)
In the present embodiment, the solid electrolyte layer 3 is formed by a single layer, but the solid electrolyte layer may be formed by a plurality of layers.

  6 and 7 are main part side sectional views showing a modified example of the electrode assembly, and correspond to FIG. 1.

  The electrode assembly 11 shown in FIG. 6 is in contact with the surface of the active material molded body 2 including the current collector 1, the active material molded body 2, and the solid electrolyte as a forming material and including the inside of the pores of the active material molded body 2. A first electrolyte layer 51 provided in contact with the surface of the first electrolyte layer 51 and a second electrolyte layer 52 provided thinly in contact with the surface of the first electrolyte layer 51. The first electrolyte layer 51 and the second electrolyte layer 52 form the solid electrolyte layer 5 as a whole. The solid electrolyte layer 5 has a configuration in which the volume of the first electrolyte layer 51 is larger than the volume of the second electrolyte layer 52.

  The solid electrolyte layer 5 in which a plurality of layers are laminated can be manufactured by carrying out the above-described method for forming the solid electrolyte layer 3 for each layer. Alternatively, after applying a liquid material for forming the first electrolyte layer 51, a first heat treatment is performed to deposit the precursor, and then a liquid material for forming the second electrolyte layer 52 is applied. Thereafter, a first heat treatment may be performed to deposit the precursor, and then a second heat treatment may be performed on the deposited multiple layers of the precursor.

  As the forming material of the first electrolyte layer 51 and the second electrolyte layer 52, the same material as the forming material of the solid electrolyte layer 3 described above can be adopted. The forming materials of the first electrolyte layer 51 and the second electrolyte layer 52 may be the same or different from each other. By providing the second electrolyte layer 52, when the electrode is provided on the surface 5a of the solid electrolyte layer 5 to produce the lithium battery having the electrode composite 11, the electrode provided on the surface 3a and the current collector 1 are activated. A short circuit connected by the material molded body 2 can be prevented.

  Further, when an alkali metal is selected as the material of the electrode to be formed when producing a lithium battery having the electrode composite 11, depending on the inorganic solid electrolyte constituting the solid electrolyte layer, the solid electrolyte layer may be formed by the reducing action of the alkali metal. There is a possibility that the constituent inorganic solid electrolyte is reduced and the function of the solid electrolyte layer is lost. In such a case, when an inorganic solid electrolyte that is stable against alkali metal is selected as a material for forming the second electrolyte layer 52, the second electrolyte layer 52 functions as a protective layer for the first electrolyte layer 51, and the first electrolyte The degree of freedom of material selection for the layer 51 is increased.

  When the second electrolyte layer is used as a protective layer for the first electrolyte layer as in the electrode assembly 11, the second electrolyte layer is interposed between the first electrolyte layer and the electrode provided on the surface of the solid electrolyte layer. If it is the structure to perform, the volume ratio of a 1st electrolyte layer and a 2nd electrolyte layer can be changed suitably.

  For example, as in the electrode assembly 12 shown in FIG. 7, the first electrolyte layer 61 is thinly formed in contact with the surface of the active material molded body 2 including the inside of the pores of the active material molded body 2, and the first electrolyte layer 61 is formed. The second electrolyte layer 62 provided in contact with the surface of the solid electrolyte layer 6 may be thick, and the volume of the second electrolyte layer 62 may be larger than the volume of the first electrolyte layer 61.

(Modification 2)
In the present embodiment, the current collector 1 is formed on the formed composite 4 after forming the composite 4 including the active material molded body 2 and the solid electrolyte layer 3. Not exclusively.

FIG. 8 is a process diagram showing a part of a modification of the method for manufacturing an electrode composite.
In the manufacturing method of the electrode assembly shown in FIG. 8, first, as shown in FIG. 8 (a), a bulk body 4X having a structure in which the active material molded body 2 and the solid electrolyte layer 3 are combined is formed. The body 4X is divided into a plurality according to the size of the target electrode assembly. In FIG. 8A, the dividing position is indicated by a broken line, and cut in a direction intersecting the longitudinal direction of the bulk body 4X at a plurality of positions in the longitudinal direction of the bulk body 4X so that the plurality of dividing surfaces face each other. It is shown as dividing.

  Next, as shown in FIG. 8B, in the composite 4Y obtained by cutting the bulk body 4X, the current collector 1 is formed on one divided surface 4α. In addition, an inorganic solid electrolyte layer (solid electrolyte layer 7) covering the active material molded body 2 exposed on the divided surface 4β is formed on the other divided surface 4β. The current collector 1 and the solid electrolyte layer 7 can be formed by the method described above.

  According to the method of manufacturing an electrode assembly having the above-described configuration, mass production of an electrode assembly that can be a high-power lithium battery is facilitated by forming the bulk body 4X in advance.

(Modification 3)
A lithium battery 200 shown in FIG. 9 has the electrode assembly 10 described above on the positive electrode side and the negative electrode side. That is, in the lithium battery 200, the electrode composite 10A is prepared on the positive electrode side and the electrode composite 10B is prepared on the negative electrode side, and the solid electrolyte layers of the electrode composite 10A and the electrode composite 10B are brought into contact with each other to be integrated. It is formed by.

  In the electrode composite 10A, a positive electrode active material is used as a forming material of the active material molded body 2A, and in the electrode composite 10B, a negative electrode active material is used as a forming material of the active material molded body 2B.

  The solid electrolyte layer 3A of the electrode assembly 10A and the solid electrolyte layer 3B of the electrode assembly 10B may be the same forming material or different forming materials.

  According to the method for manufacturing a lithium battery of this embodiment, the lithium battery 200 as described above can also be manufactured with high productivity.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the present specification, the composite is described as being used as an electrode material of a lithium battery. However, the present invention is not limited thereto, and two or more kinds of double oxide materials may be used as a porous body having a large number of pores and grooves. It can be applied to the manufacture of devices that need to be attached to the surface of the structure. For example, the number of steps can be reduced in the manufacturing process of an optical member having a complicated structure such as a photonic crystal. Further, in the field of MEMS (Micro Electro Mechanical Systems), when a complex body is filled with a complex oxide, the composite production method of the present invention can be suitably applied, and the number of processes can be reduced. be able to.

[Example]
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

(The description is the same as the example of J0172824JP01)
[1. Preparation of complex solution]
0.799 g of amorphous TiO ₂ (manufactured by Sigma Aldrich) was dissolved in 35 ml of 30% aqueous H ₂ O ₂ solution. After adding 9 ml of 35% NH ₃ aqueous solution to the obtained aqueous solution, it was allowed to stand for 1 hour with water cooling.
To the obtained aqueous solution, 2.10 g of citric acid monohydrate (manufactured by Kanto Chemical Co., Inc.) was added and stirred while heating at 60 ° C. for 30 minutes.
The obtained aqueous solution was evaporated to dryness, and pure water was added to the precipitated solid and dissolved so as to have a solution concentration of 0.5 mol / kg, whereby a peroxocitrate titanium ammonium salt (light yellow solution ( Hereinafter, an aqueous solution (hereinafter referred to as Ti-CA aqueous solution) of Ti-CA was obtained.

  Instead of citric acid monohydrate, L-malic acid (manufactured by Kanto Chemical Co., Inc.) was added in the same manner as above except that 1.54 g of L-malic acid (manufactured by Kanto Chemical Co., Ltd.) was used. An aqueous solution of MA) (hereinafter referred to as Ti-MA aqueous solution) was obtained.

  Titanium ammonium peroxoglycolate (hereinafter referred to as Ti-GA) in the same manner as above except that 0.94 g of glycolic acid (manufactured by Kanto Chemical Co., Inc.) was added instead of citric acid monohydrate. (Hereinafter referred to as Ti-GA aqueous solution).

Moreover, _{La (NO} 3) the 3 · _6H 2 O (manufactured by Kanto Chemical Co., Inc.) in an aqueous solution and dissolved at 0.5 mol / kg concentration in water, citric acid monohydrate (manufactured by Kanto Chemical Co., Inc.) 0.5 mol / An aqueous solution of lanthanum citrate complex (hereinafter referred to as an La-CA aqueous solution) was obtained by adding an aqueous solution having a kg concentration and stirring.

  Instead of citric acid monohydrate, an aqueous solution of an L-malic acid lanthanum complex (hereinafter referred to as an La-MA aqueous solution) is used in the same manner as in the above operation except that an aqueous solution of 0.5 mol / kg of L-malic acid is added. Obtained).

  Instead of citric acid monohydrate, an aqueous solution of a lanthanum glycolate complex (hereinafter referred to as an La-GA aqueous solution) is obtained in the same manner as described above except that a 0.5 mol / kg aqueous solution of glycolic acid is added. It was.

In addition, an aqueous solution obtained by dissolving LiNO ₃ (manufactured by High Purity Chemical Co., Ltd.) in water at a concentration of 0.5 mol / kg was added with a 0.5 mol / kg aqueous solution of citric acid monohydrate and stirred, so that lithium citrate An aqueous solution of the complex (hereinafter referred to as Li-CA aqueous solution) was obtained.

  Instead of citric acid monohydrate, an aqueous solution of an L-malic acid lithium complex (hereinafter referred to as an Li-MA aqueous solution) was used in the same manner as in the above operation except that an aqueous solution of 0.5 mol / kg of L-malic acid was added. Obtained).

  Instead of citric acid monohydrate, an aqueous solution of lithium glycolate complex (hereinafter referred to as Li-GA aqueous solution) was obtained in the same manner as above except that a 0.5 mol / kg aqueous solution of glycolic acid was added. It was.

[2. Complex solution mixing experiment]
The above-mentioned three kinds of lanthanum complex aqueous solutions were respectively added to the above-mentioned three kinds of titanium complex aqueous solutions at room temperature, and the presence or absence of the formation of precipitates was confirmed. The evaluation results are shown in Table 1 below. In Table 1, a combination in which precipitation occurred is indicated as “x”, and a combination in which precipitation did not occur is indicated as “◯”.

  As a result of the evaluation, it was found that when Ti-CA is used as the first complex, La-MA and La-GA can be adopted as the second complex. Similarly, when Ti-MA is used as the first complex, La-GA can be adopted as the second complex, and when La-CA is used as the first complex, Ti-GA is adopted as the second complex. I found out that

[3. Confirmation of volume shrinkage due to different ligands 1]
In this example, volume shrinkage caused by firing the metal complex prepared by the above-described method was confirmed by mass reduction. Since the volumetric shrinkage caused by the ligand burnout of the metal complex is proportional to the mass loss caused by the ligand burnout, the mass reduction that can be confirmed more easily than volume shrinkage should be measured. Can be confirmed.

  Mass reduction was confirmed by heating the metal complex to be measured or an aqueous solution of the metal complex by differential thermal and thermogravimetric analysis (TG-DTA). The heating conditions were a temperature range from room temperature to 600 ° C., a rate of temperature increase of 5 ° C./min, and an atmosphere.

  FIG. 10 shows [1. It is a chart which shows the result of having performed TG-DTA measurement about the titanium complex prepared by preparation of a complex solution], a horizontal axis is heating temperature (degreeC), and a vertical axis | shaft is mass when the mass at the time of a measurement start is 100%. The ratio (%) is shown.

  As a result of the evaluation, it was confirmed that the metal complex having a ligand having a relatively small molecular weight has a larger mass remaining after the heat treatment. That is, it was confirmed that the metal complex having a ligand having a relatively small molecular weight has less volume shrinkage after the heat treatment.

[4. Confirmation of volume shrinkage due to different ligands 2]
[1. Each metal complex aqueous solution prepared in [Preparation of complex solution] was mixed so as to contain metal atoms at a composition ratio according to the composition formula of Li _0.35 La _0.55 TiO ₃ to prepare a mixed solution.

The prepared mixed solutions are the following three types. All of the mixed solutions 1 to 3 did not cause precipitation at room temperature and were stable solutions.
Mixed solution 1: Mixed solution of Ti-CA aqueous solution, Li-CA aqueous solution, La-CA aqueous solution Mixed solution 2: Mixed solution of Ti-CA aqueous solution, Li-GA aqueous solution, La-GA aqueous solution Mixed solution 3: Ti-MA aqueous solution , Li-GA aqueous solution, La-GA aqueous solution mixed solution

  FIG. 11 is a chart showing the results of TG-DTA measurement for mixed solutions 1 to 3, where the horizontal axis represents the heating temperature (° C.), and the vertical axis represents the mass of the solution at the start of measurement as 100%. Mass (%) is shown. The conditions for TG-DTA measurement were the same as the conditions for measuring FIG.

  In the measurement results of FIG. 11, the recalculation results are shown in Table 2 below for the residual mass ratio after the measurement where the mass of the point where the solvent was removed (the point marked with a triangle in the figure) was 100%.

  As a result of the evaluation, it was confirmed that the metal complex having a ligand having a relatively small molecular weight has less volume shrinkage after the heat treatment.

[5. Difference in volume shrinkage due to concentration of mixed solution]
After preparing the mixed solution 3 of 0.25 mol / kg, the mixed solution 3 is used as a standard concentration solution (referred to as a 1-fold solution), and water as a solvent is removed while being heated on a hot plate at 90 ° C. Solutions that were concentrated 2 times, 4 times, 8 times, and 16 times in ratio were respectively prepared. These are referred to as 2 times solution, 4 times solution, 8 times solution and 16 times solution, respectively.

  Even a mixed solution of 8 times solution (2 mol / kg) or 16 times solution (4 mol / kg) could be stably prepared. In addition, when trying to prepare a mixed solution of these concentrations directly by dissolving the salt in the corresponding amount of water, the salt remained undissolved and could not be prepared.

  About the obtained 1 times-16 times liquid, mass reduction was confirmed by TG-DTA measurement. The heating conditions were a temperature range from room temperature to 570 ° C., a rate of temperature increase of 20 ° C./min, and an atmosphere.

  FIG. 12 is a chart showing the results of TG-DTA measurement for 1-fold solution to 16-fold solution, where the horizontal axis represents measurement time (minutes) and the vertical axis represents the mass of the solution at the start of measurement as 100%. The mass ratio (%) is shown.

  As a result of the evaluation, it was confirmed that the volume shrinkage after the heat treatment was small as the concentration progressed.

[6. Filling the active material compact]
After preparing 0.25 mol / kg of mixed solution 1, this mixed solution 1 was used as a reference concentration solution (referred to as 1 × solution), and the solutions concentrated 2 × and 4 × in the volume ratio by the above method, respectively. Created. These are referred to as a 2 × solution and a 4 × solution of the mixed solution 1, respectively.

  For the 1 × solution, 2 × solution, 4 × solution of the mixed solution 1 and the 1 × solution, 2 × solution, and 4 × solution of the mixed solution 3, the porous active material molded body is impregnated by the following method. Firing was performed to form a solid electrolyte layer.

First, 100 parts by mass of powdered LiCoO ₂ (manufactured by Sigma Aldrich, hereinafter referred to as LCO) and 3 parts by mass of powdered polyacrylic acid (manufactured by Kanto Chemical Co., Inc.) were mixed, and LCO and polyacrylic acid were mixed. Of mixed powder was obtained.

After 80 mg of the obtained mixed powder was weighed and filled in a pellet die, a pressure of 624 MPa was applied to form a disk-shaped pellet having a diameter of 10 mm and a thickness of 0.3 mm.
The obtained pellets were fired at 1000 ° C. for 8 hours in an air atmosphere in a muffle furnace to obtain an active material molded body.

  A solution of each concentration of the mixed solution 1 and the mixed solution 3 was placed in a sample bottle, and pellets of an active material molded body (hereinafter simply referred to as pellets) were placed therein. After reducing the whole pressure in the vacuum chamber, the active material molded body was impregnated with a mixed solution of each concentration by releasing to the atmosphere.

  The pellet impregnated with the mixed solution was taken out of the sample bottle and placed on the silicon wafer, and then the silicon wafer was heated on a hot plate at 70 ° C. for 3 minutes to remove the solvent. Thereafter, the pellet was heated at 200 ° C. for 3 minutes and further calcined at 540 ° C. for 15 minutes. After firing, the temperature was lowered by leaving it in the air, and the mass was measured.

  Hereinafter, from the impregnation of the mixed solution in the sample bottle to the baking at 540 ° C. for 15 minutes is referred to as a filling operation. Filling operation was repeatedly performed on the pellets to increase the amount of solid electrolyte filled in the pores of the pellets.

  FIG. 13 is a graph showing the relationship of the filling amount of the solid electrolyte layer with respect to the number of repetitions of the filling operation, wherein the horizontal axis is the number of repetitions of the filling operation (times), and the vertical axis is the amount of solid electrolyte charged (g). Is shown.

  As a result of the evaluation, it was found that as the ligand having a relatively low molecular weight is used for the precursor and the concentration of the mixed solution is higher, more solid electrolytes can be filled with a smaller filling operation. It was.

  From these results, the usefulness of the present invention was confirmed.

  DESCRIPTION OF SYMBOLS 1 ... Current collector, 2, 2A, 2B ... Active material molded body, 3 ... Solid electrolyte, 3, 3A, 3B, 5, 6, 7 ... Solid electrolyte layer, 3a, 5a ... Surface, 3X ... Liquid material, 4 , 4Y ... composite, 4X ... bulk, 4a ... one surface (polished surface), 4α, 4β ... divided surface, 10, 10A, 10B, 11, 12 ... electrode composite, 20 ... electrode, 51, 61 ... first Electrolyte layer, 52, 62 ... second electrolyte layer, 100, 200 ... lithium battery

Claims (8)

A first complex in which a first ligand is coordinated to a first metal atom; and a second complex in which a second ligand having a molecular weight smaller than that of the first ligand is coordinated to a second metal atom. Applying a solution having a precursor containing to the surface of the molded body including the inside of the pores of the porous molded body, and disposing the precursor on the surface;
Obtaining a metal double oxide containing the first metal atom and the second metal atom by heat-treating the precursor.   The method for producing a composite according to claim 1, wherein the arranging step includes filling the solution into the pores while heating the solution. The step of disposing the solution on the surface of the molded body in a first environment reduced in pressure from atmospheric pressure;
2. The molded body in which the solution is disposed is disposed in a second environment having a pressure higher than that in the first environment, thereby filling the solution in the pores. 2. A method for producing the composite according to 2.   The method for producing a complex according to any one of claims 1 to 3, wherein the solution is prepared by concentrating a low-concentration solution prepared in advance at a lower concentration than the solution. A first complex in which a first ligand is coordinated to a first metal atom; and a second complex in which a second ligand having a molecular weight smaller than that of the first ligand is coordinated to a second metal atom. A solution containing the precursor having the heat treatment is disposed on the surface of the active material molded body including the inside of the pores of the porous active material molded body, and the first metal atom and the second metal atom are subjected to heat treatment. Forming a solid electrolyte layer having a metal double oxide containing,
Bonding a current collector to the active material molded body exposed from the solid electrolyte layer.   The method for producing a lithium battery according to claim 5, wherein in the step of forming the solid electrolyte layer, the solution is arranged on a surface of the active material molded body while heating the solution. The step of forming the solid electrolyte layer includes disposing the solution on the surface of the active material molded body in a first environment reduced in pressure from atmospheric pressure;
The active material molded body in which the solution is disposed is disposed in a second environment having a pressure higher than that in the first environment, thereby filling the pores with the solution. The method for producing a lithium battery according to 5 or 6.   The method for producing a lithium battery according to any one of claims 5 to 7, wherein the solution is prepared by concentrating a low-concentration solution prepared in advance at a lower concentration than the solution.

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