JP7211470B2 - Electrode composites, batteries, electronic devices - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrode composite, a battery using the electrode composite, and an electronic device provided with the battery.

BACKGROUND ART Lithium batteries (including primary batteries and secondary batteries) are used as power sources for many electronic devices including portable information devices. In lithium batteries, liquid electrolytes are used because of their high ionic conductivity, but advanced technology is required to safely seal liquid electrolytes between the positive and negative electrodes so that they do not leak. is required. Therefore, solid electrolytes capable of achieving both high energy density and safety have attracted attention.

As such a solid electrolyte, for example, in Patent Document 1, grains between lithium lanthanum titanate crystal grains having a chemical formula of Li _3-x La _2/3-x TiO ₃ (0<x<0.16) A silicon-containing lithium lanthanum titanate composite solid electrolyte material is disclosed in which amorphous Si or a Si compound is present in the field.

Further, Patent Document 1 describes a method for producing a silicon-containing lithium-lanthanum titanate composite solid electrolyte material, in which a raw material solution of lithium-lanthanum titanate and a silicon precursor solution are mixed, reacted by heating, and dried. A method of obtaining a composite solid electrolyte material by pressing the obtained composite powder into a sheet and then sintering it at a high temperature of 1100° C. to 1400° C. for 1 hour to 10 hours is shown. According to the composite solid electrolyte material thus obtained, the presence of amorphous Si or a Si compound at the grain boundaries between lithium-lanthanum titanate crystal grains is said to significantly improve the grain boundary conductivity. .

Japanese Patent Publication No. 2011-529243

However, in the method for producing a silicon-containing lithium-lanthanum titanate composite solid electrolyte material of Patent Document 1, as described above, sintering is performed at a high temperature of 1100 ° C. to 1400 ° C., so that the composite powder is removed during sintering. Lithium may evaporate and escape, or lithium by-products may be produced, making it impossible to obtain a composite solid electrolyte material with a desired composition. Therefore, if the sintering temperature is set to, for example, less than 1000° C. in order to suppress the release of lithium and the generation of by-products, the interface between the lithium-lanthanum titanate crystal grains is not sufficiently sintered, and the grain boundary resistance increases and ion There was a problem that conductivity decreased.

The present invention has been made to solve at least part of the above problems, and can be implemented as the following forms or application examples.

[Application Example] An electrolyte precursor solution according to this application example includes a metal compound containing an element constituting an electrolyte, a solvent capable of dissolving the metal compound, and an anionic surfactant having a sulfate group. Characterized by

According to the electrolyte precursor solution of this application example, since the anionic surfactant having a sulfate group is included, the active material particles used as the electrode material of the battery and the electrolyte precursor solution are brought into contact with each other to cause a reaction. Then, sulfate groups, which are hydrophilic groups, are bonded to the surfaces of the active material particles. Therefore, the presence of sulfate groups between the active material particles and the electrolyte (metal compound) facilitates the dissociation of the active material as ions, thereby improving the ionic conductivity between the active material particles and the electrolyte. can. That is, it is possible to provide an electrolyte precursor solution capable of forming an electrolyte having high ionic conductivity.

In the electrolyte precursor solution described in the above application examples, it is preferable that the anionic surfactant is contained in an amount of 5 times or more and 15 times or less of the critical micelle concentration with respect to the solvent.
According to this, the ionic conductivity can be improved by ensuring that the sulfate group exists between the active material particles and the electrolyte.

In the electrolyte precursor solution according to the above application examples, the anionic surfactant preferably contains lithium.
According to this, by including lithium in the anionic surfactant, the amount of lithium as the active material can be increased, and the ionic conductivity of lithium ions can be further improved.

In the electrolyte precursor solution described in the above application examples, the anionic surfactant preferably contains a hydrophobic group having 4 or more carbon atoms or a fluorinated alkyl group, which is a combination of a sulfate group and lithium.
According to this, since it exhibits hydrophobicity when it contains a hydrophobic group having 4 or more carbon atoms or a fluorinated alkyl group, it exhibits a function as a surfactant, and this anionic surfactant is an active material. By orienting the sulfate groups toward the surface of the particles, the wettability of the electrolyte precursor solution, which exhibits hydrophobicity, can be improved.

[Application Example] A method for manufacturing an electrode assembly according to this application example includes a step of forming an active material portion having voids therein using active material particles; It is characterized by comprising a step of impregnating with a precursor solution and drying, and a step of firing the active material portion impregnated with the electrolyte precursor solution at a temperature lower than the melting point of the active material particles.

According to this application example, the active material part composed of the active material particles and the electrolyte are combined, and the sulfate group of the anionic surfactant is interposed between the surface of the active material particles and the electrolyte in the gaps of the active material part. An electrode assembly with improved ionic conductivity can be produced by using the Therefore, it is possible to secure the desired ion conductivity even if the firing temperature is lower than the melting point of the active material particles. It is possible to produce an electrode assembly having a desired composition by suppressing time-consuming depletion of lithium and generation of lithium by-products.

In the manufacturing method of the electrode assembly described in the above application example, it is preferable to repeatedly perform the steps of impregnating the active material portion with the electrolyte precursor solution and drying.
According to this method, it is possible to manufacture an electrode assembly in which the filling ratio of the electrolyte to the voids in the active material portion is improved, the internal resistance is reduced, and the electric capacity per unit volume, that is, the energy density is improved. .

In the method for manufacturing an electrode composite according to the above application example, the metal compound of the electrolyte precursor solution contains an element that constitutes the crystalline first electrolyte portion and the amorphous second electrolyte portion after firing. is preferred.
According to this method, the electrolyte obtained after firing includes the crystalline first electrolyte portion whose ion conduction direction is restricted and the amorphous second electrolyte portion whose ion conduction direction is difficult to be restricted. A higher ionic conductivity can be achieved than in the case of only the crystalline first electrolyte portion.

In the method for manufacturing the electrode assembly according to the application example, the third electrolyte having a melting point lower than that of the first electrolyte portion and the second electrolyte portion and forming the amorphous third electrolyte portion after cooling is melted. , impregnating the active material portion and cooling.
According to this method, since the third electrolyte portion is further formed in the voids of the active material portion, ion conduction paths (ion conduction paths) between the active material particles and the electrolyte are further increased, resulting in higher ion conductivity. can be realized.

[Application Example] An electrode assembly according to this application example includes a plurality of active material particles, an active material portion having voids therein, a crystalline first electrolyte portion, and an amorphous second electrolyte portion. an electrolyte, wherein each of the active material particles, the first electrolyte portion, and the second electrolyte portion contains lithium, the electrolyte is contained in the voids of the active material portion, and the voids are between the surfaces of the active material particles and the electrolyte; It is characterized by intervening lithium sulfate.

According to this application example, the electrolyte includes the crystalline first electrolyte portion and the amorphous second electrolyte portion. Conduction (delivery) of lithium ions between the first electrolyte portion and the second electrolyte portion is efficiently performed. In addition, the electrolyte is contained in the voids of the active material portion, and lithium sulfate intervenes between the surfaces of the active material particles and the electrolyte in the voids, thereby promoting the dissociation of lithium ions on the surfaces of the active material particles. That is, in addition to improving the ionic conductivity between the first electrolyte part and the second electrolyte part, an electrode composite with improved ionic conductivity due to an improvement in the lithium ion concentration between the active material particles and the electrolyte. can provide.

In the electrode assembly according to the above application example, the first electrolyte part is a metal compound represented by the following formula (1) having a garnet-type crystal structure, the metal A having a crystal radius of 78 pm or more, A is preferably contained in the first electrolyte part and the second electrolyte part.
_{Li7 - xLa3} (Zr2 _{- xAx} )O12 (1)
0.05≦x≦0.6, and at least one of metal A is selected from Nb, Ta, and Sb.
According to this configuration, since the metal A having a crystal radius of 78 pm or more replaces part of the Zr sites of the first electrolyte portion, the metal A is generated. That is, at the interface where the first electrolyte part and the second electrolyte part are in contact with each other, it is difficult to make the interface clear due to the concentration gradient of the metal A. That is, lithium ion conduction is facilitated between the first electrolyte portion and the second electrolyte portion, and an electrode composite in which the active material portion and an electrolyte having high ionic conductivity are combined can be provided.

In the electrode assembly according to the above application example, the electrolyte preferably includes an amorphous third electrolyte portion having a melting point lower than that of the first electrolyte portion and the second electrolyte portion.
According to this configuration, the electrolyte including the third electrolyte portion in addition to the first electrolyte portion and the second electrolyte portion is included in the voids of the active material portion, thereby increasing ion conduction paths and further improving ion conductivity. Electrode composites can be realized. Further, since the third electrolyte part has a lower melting point than the first electrolyte part and the second electrolyte part, it is possible to melt the electrolyte material constituting the third electrolyte part and fill the voids of the active material part. becomes. That is, when filling the active material portion with the third electrolyte portion, it is possible to prevent compositional changes due to heat in the first electrolyte portion and the second electrolyte portion.

[Application Example] A battery according to this application example includes the electrode assembly according to the above application example, a current collector provided on one side of the electrode assembly so as to be in contact with the active material particles, and the electrode assembly and a negative electrode provided on the other surface side of the.
According to this application example, the electrode composite is a composite of the active material portion and the electrolyte, and has high energy density and ionic conductivity. be able to.

In the battery according to the above application example, the negative electrode is preferably made of metallic lithium or an alloy containing lithium, and preferably has a lithium reduction-resistant layer between the other surface of the electrode assembly and the negative electrode.
According to this configuration, by forming the negative electrode from metallic lithium or an alloy containing lithium, it is possible to increase the number of lithium supply sources and realize a battery with a larger capacity than in the case where the negative electrode is formed from other active materials. Further, by providing the lithium reduction-resistant layer between the other surface of the electrode composite and the negative electrode, the lithium reduction-resistant layer can prevent the growth of lithium dendrites on the negative electrode side due to charging and discharging. That is, it is possible to prevent a short circuit between the electrode composite functioning as the positive electrode and the negative electrode due to the growth of lithium dendrites.

[Application Example] An electronic device according to this application example includes the battery according to the application example described above.
According to this application example, it is possible to provide an electronic device that can withstand repeated use over a long period of time because it has a battery with excellent charge/discharge characteristics and a large capacity.

1 is a schematic perspective view showing the structure of a lithium battery according to a first embodiment; FIG. 1 is a schematic cross-sectional view showing the structure of a lithium battery according to a first embodiment; FIG. FIG. 4 is an enlarged view showing an active material portion, a first electrolyte portion, a second electrolyte portion, and a third electrolyte portion in the electrode composite of the first embodiment; 4 is a flow chart showing a method for manufacturing an electrode assembly in the lithium battery of the first embodiment; FIG. 4 is a schematic diagram showing the state of an anionic surfactant contained in an electrolyte precursor solution. Schematic which shows the process in the manufacturing method of an electrode assembly. Schematic which shows the process in the manufacturing method of an electrode assembly. Schematic which shows the process in the manufacturing method of an electrode assembly. Schematic which shows the process in the manufacturing method of an electrode assembly. Schematic which shows the process in the manufacturing method of an electrode assembly. The perspective view which shows the structure of the wearable apparatus as an electronic device of 2nd Embodiment. FIG. 4 is a schematic cross-sectional view showing the structure of a modified lithium battery.

Embodiments embodying the present invention will be described below with reference to the drawings. The drawings to be used are enlarged or reduced as appropriate so that the parts to be described can be recognized.

(First embodiment)
<Battery>
First, the battery of the present embodiment will be described with reference to FIGS. 1 to 3, taking a lithium battery as an example. FIG. 1 is a schematic perspective view showing the structure of the lithium battery of the first embodiment, FIG. 2 is a schematic cross-sectional view showing the structure of the lithium battery of the first embodiment, and FIG. 4 is an enlarged view showing a material part, a first electrolyte part, a second electrolyte part, and a third electrolyte part; FIG.

As shown in FIG. 1, the lithium battery 100 of the present embodiment includes an electrode composite 10 functioning as a positive electrode, an electrolyte layer 24 sequentially laminated on the electrode composite 10, and a negative electrode 30. there is It also has a current collector 41 in contact with the electrode assembly 10 and a current collector 42 in contact with the negative electrode 30 . Since the electrode composite 10, the electrolyte layer 24, and the negative electrode 30 are all composed of a solid phase containing lithium, the lithium battery 100 is a chargeable/dischargeable solid secondary battery.

The lithium battery 100 of this embodiment is, for example, disk-shaped, and has an external size of, for example, 10 mmφ and a thickness of, for example, approximately 0.3 mm. Since it is a compact, thin, and chargeable/dischargeable solid secondary battery, it can be suitably used as a power source for mobile information terminals such as smartphones. The size and thickness of the lithium battery 100 are not limited to these values as long as they can be molded. When the size of the outer shape is 10 mmφ as in the present embodiment, the thickness is about 0.1 mm from the viewpoint of moldability when it is thin, and when it is thick, it is estimated from the viewpoint of lithium ion conductivity of the electrolyte, up to about 1 mm. However, if it is too thick, the utilization efficiency of the active material will be lowered. In addition, the shape of the lithium battery 100 is not limited to a disc shape, and may be a polygonal disc shape. Each layer will be described in detail below.

As shown in FIG. 2 , the electrode assembly 10 functioning as a positive electrode includes an active material portion 11 made up of a plurality of active material particles 11 a and an electrolyte 20 . Although the detailed configuration and manufacturing method of the electrode assembly 10 will be described later, the electrode assembly 10 includes an active material portion 11 that is configured by sintering the active material particles 11a in contact with each other. 10 is given electronic conductivity. Moreover, the current collector 41 is provided so as to be in contact with the plurality of active material particles 11a. The electrolyte 20 includes a crystalline first electrolyte portion 21 , an amorphous second electrolyte portion 22 and a third amorphous electrolyte portion 23 . The crystalline first electrolyte portion 21 and the amorphous second electrolyte portion 22 are selected from materials having higher ionic conductivity than the third electrolyte portion 23 .
Further, for the amorphous third electrolyte portion 23, a material having a melting point lower than that of the material constituting the active material particles 11a, the first electrolyte portion 21, and the second electrolyte portion 22 is selected and used.

The electrolyte layer 24 provided between the electrode composite 10 and the negative electrode 30 does not contain the active material particles 11a, and is configured using an ion-conductive electrolyte. Such an electrolyte layer 24 suppresses the formation of lithium dendrites on the negative electrode 30 side due to charging and discharging of the lithium battery 100, and the electrode composite 10 provided with electronic conductivity and the negative electrode 30 are separated by lithium dendrites. It functions as a lithium reduction-resistant layer that prevents electrical short-circuiting.

In the lithium battery 100 of the present embodiment, the surface of the electrode composite 10 in contact with the current collector 41 is hereinafter referred to as one surface 10c, and the surface of the electrode composite 10 in contact with the electrolyte layer 24 is referred to as the other surface 10a.

<Electrode composite>
FIG. 3 is a diagram schematically showing how a thinly sliced sample of the electrode assembly 10 is observed with a transmission electron microscope (TEM). As shown in FIG. 3, the electrode assembly 10 includes a plurality of active material particles 11a forming the active material portion 11, and an electrolyte 20 is filled between the active material particles 11a. Both the active material particles 11a and the first electrolyte parts 21 of the electrolyte 20 are particulate, and the particle diameter of the first electrolyte parts 21 is overwhelmingly smaller than the particle diameter of the active material particles 11a. The first electrolyte part 21 is in contact with the surface of the active material particles 11a and exists between the active material particles 11a. In addition, amorphous second electrolyte portion 22 and third electrolyte portion 23 are present so as to fill gaps between active material particles 11 a and be in contact with active material particles 11 a and first electrolyte portion 21 . It is preferable that the gaps between the particles of the active material particles 11a are completely filled with the electrolyte 20, but in reality, they partially include the spaces 11s.

The interface between the active material particles 11a and the electrolyte 20, the interface of the third electrolyte portion 23 in the electrolyte 20, and the interface of the space 11s between the active material particles 11a are distinct, but the interface between the first electrolyte portion 21 in the electrolyte 20 and the The interface of the second electrolyte part 22 is not clear. In FIG. 3, for convenience of illustration, the particle shapes of the active material particles 11a and the first electrolyte part 21 are spherical, but the actual particle shapes are not necessarily spherical and are irregular.

From the viewpoint of exhibiting electron conductivity by bringing the active material particles 11a into contact with each other, the average particle size D50 of the active material particles 11a is preferably 500 nm or more and less than 10 μm. On the other hand, the particle diameter of the first electrolyte part 21 is, for example, an average particle diameter D50 and is on the submicron level in relation to the manufacturing method to be described later. In FIG. 3 , the particles of the first electrolyte part 21 are shown in a identifiable state, but in reality, the first electrolyte part 21 is formed by the fine particles of the submicron level coming into contact with each other.

The active material particles 11a, which are the positive electrode active material constituting the active material portion 11, contain at least Li and at least one transition metal selected from V, Cr, Mn, Fe, Co, Ni, and Cu as a constituent element. It is preferable to use a lithium composite metal oxide containing as because it is chemically stable. Examples of such lithium composite metal oxides include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , Li ₂ Mn ₂ O ₃ , Li( _{NixMnyCo 1-xy )} O ₂ [0<x+y<1 ], Li ₍ NixCoyAl1 _{-xy ) O2} [0<x _{+ y} < ₁ ], _{LiCr0.5Mn0.5O2} , _LiFePO4 , _{Li2FeP2O7 , LiMnPO4} , _{LiFeBO3 , Li3V2} (PO ₄ ) ₃ , Li ₂ CuO ₂ , Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ and the like. Lithium mixed metal oxides also include solid solutions in which some atoms in the crystal of these lithium mixed metal oxides are substituted with typical metals, alkali metals, alkaline earth metals, lanthanides, chalcogenides, halogens, etc. , these solid solutions can also be used as the active material particles 11a. In this embodiment, particles of LiCoO ₂ are used as the active material particles 11a, and hereinafter they may be abbreviated as LCO particles.

The method of forming the active material portion 11 including a plurality of active material particles 11a is a green sheet method, press sintering method, CVD, PLD, sputtering, aerosol deposition, or other vapor phase deposition method to form a thin film. good too. Furthermore, a single crystal grown from a melt or solution may be used. When the green sheet method or the press sintering method is used as the method for forming the active material portion 11, voids are generated between the active material particles 11a after sintering. Such voids communicate with each other inside the active material portion 11 . By filling the voids with the electrolyte 20, the contact area between the active material particles 11a and the electrolyte 20 increases, and the interfacial impedance of the electrode assembly 10 can be reduced. Considering the interfacial impedance in the electrode composite 10, the bulk density porosity in the active material portion 11 is preferably 40% to 60%, and the filling rate of the electrolyte 20 in the voids is preferably 80% or more. The bulk density porosity a is derived from the following formula (1) using the apparent volume v of the active material portion 11, the mass w, and the density ρ of the active material particles 11a.
a={1−w/(v・ρ)}×100 (1)
The filling rate of the electrolyte 20 can be obtained by dividing the value obtained by subtracting the mass before filling from the mass after filling by the density of the electrolyte 20 .

Moreover, the electrical resistivity of the active material portion 11 is preferably 700 Ωcm or less. Since the active material portion 11 has such an electrical resistivity, a sufficient output can be obtained in the lithium battery 100 using the electrode composite 10 . The electrical resistivity can be obtained by attaching a copper foil used as an electrode to the surface of the active material portion 11 and performing DC polarization measurement.

<Electrolyte>
The electrolyte 20 (the first electrolyte part 21, the second electrolyte part 22, the third electrolyte part 23) and the electrolyte layer 24 included in the electrode composite 10 are solid electrolytes, and include oxides, sulfides, halides, and nitrides. Crystalline or amorphous metal compounds such as hydrides, borides, and the like can be used.

Examples of oxide crystals include Li _0.35 La _0.55 TiO ₃ , Li _0.2 La _0.27 NbO ₃ , and some of the elements of these crystals are N, F, Al, Sr, Sc, Nb, Ta, Sb, and lanthanoid elements. _{Perovskite -} type crystals or _{perovskite -} like crystals substituted with, for example, _{Li7La3Zr2O12 , Li5La3Nb2O12 , Li5BaLa2TaO12} , and some of the elements of these _{crystals are} N, F, Garnet-type crystals or garnet-like crystals substituted with Al, Sr, Sc, Nb, Ta, Sb, _lanthanide elements, etc. _{, Li1.3Ti1.7Al0.3} ( _PO4 ) _{3 , Li1.4Al0.4Ti1.6 ( PO4} ) ₃ , Li _1.4 Al _0.4 Ti _1.4 Ge _0.2 (PO ₄ ) ₃ , and NASICON-type crystals obtained by substituting part of these crystals with N, F, Al, Sr, Sc, Nb, Ta, Sb, lanthanide elements, etc., Li ₁₄ LISICON-type crystals such as ZnGe ₄ O ₁₆ , and other crystals such as Li _3.4 V _0.6 Si _0.4 O ₄ , Li _3.6 V _0.4 Ge _0.6 O ₄ , Li _2+x C _1-x B _x O ₃ . be able to.

_Examples of _{sulfide crystals include Li10GeP2S12 , Li9.6P3S12 , Li9.54Si1.74P1.44S11.7Cl0.3 , and Li3PS4 .}

Also. Examples of other amorphous materials include Li ₂ O--TiO ₂ , La ₂ O ₃ --Li ₂ O--TiO ₂ , LiNbO ₃ , LiSO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ --Li ₄ SiO ₄ , _{Li4GeO4 - Li3VO4} , _{Li4SiO4 - Li3VO4 , Li4GeO4 - Zn2GeO2 , Li4SiO4 - LiMoO4 , Li3PO4 - Li4SiO4 , Li4} SiO4 _{- Li4ZrO4} , _{SiO2 -} P2O5 _- Li2O, _{SiO2 -} P2O5 _- LiCl, Li2O _- LiCl _{- B2O3 , LiAlCl4} , _LiAlF4 , LiF _- Al ₂ O ₃ , LiBr—Al ₂ O ₃ , Li _2.88 PO _3.73 N _0.14 , Li ₃ N—LiCl, Li ₆ NBr ₃ , Li ₂ S—SiS ₂ , Li ₂ S—SiS ₂ —P ₂ S ₅ and the like. be able to.

Among the solid electrolytes described above, the solid electrolyte used in the first electrolyte part 21 has excellent ion conductivity, and some of the elements of the crystal of Li ₇ La ₃ Zr ₂ O ₁₂ are mixed with Al, Sr, Sc Garnet-type crystals or garnet-like crystals substituted with elements such as , Nb, Ta, Sb, and lanthanoid elements are preferred. Specifically, those represented by the following formula (2) can be mentioned.

_{Li7 - xLa3} (Zr2 _{- xAx} )O12 (2)
0.05≦x≦0.6, metal A has an atomic crystal radius of 78 pm or more, and is selected from at least one of Nb, Ta, and Sb. Hereinafter, the lithium composite metal oxide represented by the above formula (2) is abbreviated as LLZrAO. For example, the total ionic conductivity of LLZrNbO (x=0.3) is 1.6×10 ⁻⁴ [S/cm] (the ionic conductivity of the intraparticle bulk is 6.2×10 ⁻⁴ [S/cm ], and the ionic conductivity of the grain boundary is 2.2×10 ⁻⁴ [S/cm]).

According to the method for manufacturing the electrode assembly 10 described later, the second electrolyte portion 22 is made of an amorphous solid electrolyte containing the same metal A as the first electrolyte portion 21 . Therefore, as shown in the above formula (2), the metal A in the first electrolyte portion 21 replaces part of the Zr sites in the crystal and is also included in the amorphous second electrolyte portion 22, Between the first electrolyte portion 21 and the second electrolyte portion 22, a concentration gradient of the metal A is generated, and the interface between the crystalline first electrolyte portion 21 and the amorphous second electrolyte portion 22 is clearly defined. hard to be Lithium ions are hopping-conducted in the crystalline first electrolyte portion 21 and conducted by ion diffusion in the amorphous second electrolyte portion 22 . Therefore, by connecting the crystalline first electrolyte portions 21 with the amorphous second electrolyte portions 22, lithium ions are ion-diffused and conducted between the crystalline first electrolyte portions 21. Therefore, the crystalline The ionic conductivity in the electrolyte 20 is improved compared to the case where grain boundaries exist between the first electrolyte portions 21 of the solid.

The third electrolyte part 23 has high coverage of the surface and internal voids of the active material part 11 (porous active material sintered body), and the active material particles 11a, the first electrolyte part 21, and the second electrolyte having the above melting points. Li2 ₊ xC1 _{- xBxO3 ,} which is a lithium composite oxide containing carbon (C) and boron (B), which is lower than that of part 22, and similar substances are particularly preferably used. Hereinafter, Li _2+x C _1-x B _x O ₃ is abbreviated as LCBO.

Further, according to the manufacturing method of the electrode composite 10 described later, lithium sulfate exists between the surface of the active material particles 11 a and the electrolyte 20 . Lithium sulfate is derived from an anionic surfactant contained in the electrolyte precursor solution used to form electrolyte 20 . Lithium sulfate present between the surfaces of the active material particles 11a and the electrolyte 20 is about one molecular layer and is not shown in FIG. By interposing lithium sulfate between the surfaces of the active material particles 11a and the electrolyte 20, the dissociation of lithium ions as the active material is promoted.

As a method for forming the electrolyte layer 24 using the solid electrolyte described above, in addition to a solution process such as a so-called sol-gel method and an organometallic thermal decomposition method that involve a hydrolysis reaction of an organometallic compound, CVD method, ALD method, green sheet method and screen printing method using slurry of solid electrolyte particles, aerosol deposition method, sputtering method using appropriate target and gas atmosphere, PLD method, flux using melt or solution law and so on. In this embodiment, a sputtering method is used as a method of forming the electrolyte layer 24 .

In the present embodiment, the same solid electrolyte is used for the third electrolyte part 23 included in the electrode assembly 10 and the electrolyte layer 24, but different solid electrolytes may be used.

The electrode composite 10 is polished so that the plurality of active material particles 11a are exposed on one surface 10c in contact with the current collector 41 . Electrical resistance between the electrode assembly 10 and the current collector 41 is reduced by connecting the current collector 41 to the plurality of active material particles 11a exposed on one surface 10c.

<Negative Electrode>
Nb ₂ O ₅ , V ₂ O ₅ , TiO ₂ , In ₂ O ₃ , ZnO, SnO ₂ , NiO, ITO (Indium Tin Oxide), AZO (Al-doped Zinc Oxide), FTO (F _- doped Tin Oxide), anatase phase of _TiO2 , Lithium composite metal oxides such as _{Li4Ti5O12 , Li2Ti3O7} , Li, Si, _Sn , Si _- Mn, Examples include metals such as Si—Co, Si—Ni, In, and Au, alloys containing these metals, carbon materials, and substances in which lithium ions are inserted between layers of carbon materials. Considering the discharge capacity of the small and thin lithium battery 100, the negative electrode 30 is preferably made of metal Li or a single metal or alloy forming a lithium alloy. The alloy is not particularly limited as long as it is capable of intercalating and deintercalating lithium, but it preferably contains a metal or metalloid element other than carbon of groups 13 and 14, more preferably aluminum, silicon and tin. It is an alloy or compound containing these atoms. These may be used alone, or two or more of them may be used in any combination and ratio. The alloys include lithium alloys such as Li--Al, Li--Ni, Li--Si, Li--Sn and Li--Sn--Ni, silicon alloys such as Si--Zn, Sn--Mn, Sn--Co, Sn--Ni, Tin alloys such as Sn--Cu and Sn--La, Cu ₂ Sb, La ₃ Ni ₂ Sn ₇ and the like can be exemplified.

The method for forming the negative electrode 30 using the negative electrode active material includes a solution process such as a so-called sol-gel method and an organometallic thermal decomposition method that involve a hydrolysis reaction of an organometallic compound, and a CVD method in a suitable metal compound and gas atmosphere. , ALD method, green sheet method and screen printing method using slurry of solid negative electrode active material, aerosol deposition method, sputtering method using appropriate target and gas atmosphere, PLD method, vacuum deposition method, plating method, thermal spraying method etc., may be used.

<Current collector>
The current collectors 41 and 42 are made of, for example, 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 metal (elemental metal) selected from the metal group of palladium (Pd), or from the metal group An alloy or the like composed of two or more selected metals is used.

In this embodiment, copper (Cu) is used as the current collectors 41 and 42 . The thickness of the current collectors 41 and 42 is, for example, 20 μm to 40 μm. It should be noted that the lithium battery 100 does not necessarily have to include the pair of current collectors 41 and 42 and may include one of the pair of current collectors 41 and 42 . For example, when a plurality of lithium batteries 100 are stacked so as to be electrically connected in series, the lithium battery 100 may have only the current collector 41 of the pair of current collectors 41 and 42. .

<Method for producing lithium battery (method for producing electrode assembly)>
Next, the method for manufacturing the lithium battery 100 of this embodiment is characterized by the method for manufacturing the electrode assembly 10 . Therefore, a method for manufacturing the electrode assembly 10 will be described with reference to FIGS. 4 to 10. FIG. FIG. 4 is a flow chart showing the method for manufacturing the electrode assembly in the lithium battery of the first embodiment, and FIG. 5 is a schematic diagram showing the state of the anionic surfactant contained in the electrolyte precursor solution. 6 to 10 are schematic diagrams showing the steps in the manufacturing method of the electrode assembly.

As shown in FIG. 4, the method for manufacturing the electrode assembly 10 of the present embodiment includes an electrolyte precursor solution adjustment step (step S1), an active material portion 11 formation step (step S2), an active material portion 11 a step of impregnating and drying the electrolyte precursor solution (step S3), a firing step (step S4), a third electrolyte filling step (step S5), and a polishing step (step S6). there is Hereinafter, each step will be described in order.

In step S1, first, various metal elements contained in the first electrolyte part 21 and the second electrolyte part 22 are obtained as metal compounds, and a metal compound solution is prepared by dissolving the metal compounds in a solvent. The target metal compounds in this embodiment are lithium compounds, lanthanum compounds, zirconium compounds, niobium compounds, tantalum compounds, and antimony compounds.

Lithium compounds (lithium sources) include, for example, lithium metal salts such as lithium chloride, lithium nitrate, lithium acetate, lithium hydroxide, lithium carbonate, lithium methoxide, lithium ethoxide, lithium propoxide, lithium isopropoxide, lithium Lithium alkoxides such as butoxide, lithium isobutoxide, lithium secondary butoxide, lithium tertiary butoxide, and dipivaloylmethanatritium can be mentioned, and one or more of these can be used in combination.

Lanthanum compounds (lanthanum sources) include, for example, lanthanum metal salts such as lanthanum chloride, lanthanum nitrate and lanthanum acetate, lanthanum trimethoxide, lanthanum triethoxide, lanthanum tripropoxide, lanthanum triisopropoxide, lanthanum tributoxide, Lanthanum alkoxides such as lanthanum triisobutoxide, lanthanum trisecondary butoxide, lanthanum tritertiary butoxide, and dipivaloylmethanatrantanane can be mentioned, and one or more of these can be used in combination.

Zirconium compounds (zirconium sources) include, for example, zirconium metal salts such as zirconium chloride, zirconium oxychloride, zirconium oxynitrate, zirconium oxyacetate and zirconium acetate, zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetrapropoxide, zirconium zirconium alkoxides such as tetraisopropoxide, zirconium tetrabutoxide, zirconium tetraisobutoxide, zirconium tetra-secondary butoxide, zirconium tetratertiary butoxide, and dipivaloylmethanatozirconium; They can be used in combination.

Niobium compounds (niobium sources) as compounds having an atomic crystal radius of 78 pm or more include, for example, niobium chloride, niobium oxychloride, niobium oxalate, niobium metal salts such as niobium pentaacetylacetonate, niobium pentaethoxide, Niobium alkoxides such as niobium pentapropoxide, niobium pentaisopropoxide, and niobium pentasecondary butoxide can be mentioned, and one or more of these can be used in combination.

Similarly, tantalum compounds (tantalum sources) as compounds having an atomic crystal radius of 78 pm or more include, for example, tantalum metal salts such as tantalum chloride and tantalum bromide, tantalum pentamethoxide, tantalum pentaethoxide, tantalum pentaiso tantalum alkoxides such as propoxide, tantalum penta-normal propoxide, tantalum pentaisobutoxide, tantalum penta-normal butoxide, tantalum penta-secondary butoxide, tantalum penta-tertiary butoxide, and the like, one or more of these in combination can be used.

Furthermore, antimony compounds (antimony sources) as compounds having an atomic crystal radius of 78 pm or more include, for example, antimony metal salts such as antimony bromide, antimony chloride and antimony fluoride, antimony trimethoxide, antimony triethoxide, Antimony alkoxides such as antimony triisopropoxide, antimony tri-normal propoxide, antimony tri-isobutoxide and antimony tri-normal butoxide can be mentioned, and one or more of these can be used in combination.

As the solvent, a single solvent or a mixed solvent of water and an organic solvent that can dissolve lithium compounds, lanthanum compounds, zirconium compounds, and metal compounds having an atomic crystal radius of 78 pm or more is used.

Examples of such organic solvents include, but are not limited to, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, allyl alcohol, 2-n-butoxyethanol, ethylene glycol, propylene glycol, butylene glycol, Glycols such as hexylene glycol, pentanediol, hexanediol, heptanediol, dipropylene glycol, ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl formate, ethyl formate, methyl acetate, methyl acetoacetate, etc. esters, ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, organic acids such as formic acid, acetic acid, propionic acid, toluene, Aromatics such as o-xylene and p-xylene are included.

As described above, the solvent is appropriately selected depending on the metal compound containing the metal element that constitutes the first electrolyte portion 21 and the second electrolyte portion 22 . Therefore, not only water but also an oily organic solvent may be selected as the solvent, and the solvent is not limited to one type. can be secured.

To prepare the metal compound solution, each of the metal compounds described above is weighed so as to have a concentration in moles (mol), added to a selected solvent, mixed and dissolved. In order to sufficiently dissolve the metal compound, the solvent is heated and mixed as necessary.

Next, considering the compositions of the first electrolyte part 21 and the second electrolyte part 22 to be obtained as products, the metal compound solutions in which the metal compounds are dissolved are weighed and mixed for each metal source. , to obtain an electrolyte precursor solution. Specifically, three metal compound solutions each containing a lithium compound, a lanthanum compound, and a zirconium compound, and a metal compound solution containing at least one metal compound selected from a niobium compound, a tantalum compound, and an antimony compound, An anionic surfactant is mixed at a predetermined mixing ratio.

As described above, the anionic surfactant causes lithium sulfate to promote dissociation of lithium ions between the active material particles 11a and the electrolyte 20 (in this case, the first electrolyte part 21 and the second electrolyte part 22). and preferably contains lithium as an active material. Further, the anionic surfactant contains a hydrophobic group R in which a sulfate group (SO ₄ ²⁻ ), which is a hydrophilic group, and lithium (Li) are bonded, and the hydrophobic group R has 4 or more carbon atoms. or a fluorinated alkyl group. Hydrophobicity is improved by making the number of carbon atoms of the hydrophobic group R 4 or more, or by using a fluorinated alkyl group, and the function as a surfactant can be exhibited, and the range of selection of the above solvent can be expanded on the oily side. becomes. Therefore, an anionic surfactant is represented by the following formula (3).

R—SO ₄ —Li (3)
Specific examples of the hydrophobic group R having 4 or more carbon atoms include n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, Linear alkyl groups such as n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group or n-octadecyl group, sec- branched alkyl groups such as butyl, tert-butyl, iso-amyl, tert-amyl or 2-ethylhexyl groups, or 2-fluoroethyl or 2,2,2-trifluoroethyl groups and fluorinated alkyl groups such as

In the present embodiment, lithium dodecyl sulfate (LDS), in which a sulfate group (SO ₄ ²⁻ ) and lithium (Li) are bonded to a hydrophobic group R, which is an alkyl group having 12 carbon atoms, is used as an anionic surfactant. Using.

As shown in FIG. 5, for example, when the anionic surfactant 25 is mixed with an aqueous solvent, the sulfate group (SO ₄ ²⁻ ) faces outward and the hydrophobic group R faces inward in the solvent to form a plurality of surfactants. A micelle 25m is formed in which the anionic surfactant 25 is collected. When the anionic surfactant 25 is mixed with an oily solvent, a plurality of anionic surfactants 25 are gathered with the hydrophobic group R facing outward and the sulfate group (SO ₄ ^2- ) facing inward. Micelles 25m are formed. The concentration of anionic surfactant 25 at which micelles 25m are thus formed in the solvent is called the critical micelle concentration (CMC). The critical micelle concentration (CMC) of lithium dodecyl sulfate (LDS) as the anionic surfactant 25 is 3.0 mmol (millimol)/kg (solution).

The content of the anionic surfactant 25 in the electrolyte precursor solution should be such that the anionic surfactant 25 is dispersed to some extent in the solution from the viewpoint of reliably drawing out the effect of the anionic surfactant 25. preferable. In this embodiment, the content of the anionic surfactant 25 with respect to the total amount of the solution is 5 times or more and 15 times or less of the critical micelle concentration. When the content of the anionic surfactant 25 in the solution exceeds 15 times the critical micelle concentration, the anionic surfactant 25 is mostly micellized in the solution, and the anionic surfactant 25 dispersed in the solution becomes quantity will decrease. Then, the process proceeds to step S2.

In step S2, a porous active material portion 11 is formed. Specifically, first, a particulate (powder) positive electrode active material (lithium mixed metal oxide) is prepared. In this embodiment, particulate LiCoO ₂ (hereinafter simply referred to as LCO) was used as the positive electrode active material. The average particle size (D50) of the positive electrode active material is, for example, preferably 300 nm or more and 20 μm or less, more preferably 5 μm or more and 15 μm or less. The average particle size can be measured, for example, by dispersing LCO particles in n-octanol at a concentration of 0.1% by mass to 10% by mass, and then using a light scattering particle size distribution analyzer (for example, Nanotrac UPA manufactured by Nikkiso Co., Ltd. - EX250). If the average particle size is too small, the voids become small, making it difficult to fill the electrolyte in the subsequent steps. On the other hand, if the average particle diameter is too large, the specific surface area of the active material portion 11 becomes small, and the output of the lithium battery 100 becomes low.

Next, as shown in FIG. 6, the powder 11p of the positive electrode active material is placed in a die (molding die) 81, and is compression-molded by applying a pressure of, for example, 0.1 MPa to 5.0 MPa by a pressure unit 82. . Furthermore, this compressed body is heat-treated and sintered to obtain the active material portion 11 . This heat treatment is performed at a temperature of 850° C. or higher and lower than the melting point or the decomposition point of the lithium composite metal oxide used as the positive electrode active material, whichever is lower, in consideration of the evaporation of lithium. will be Since the melting point of LCO as a lithium composite metal oxide is higher than 1000°C, this heat treatment is preferably performed at 900°C or higher and 1000°C or lower. Furthermore, this heat treatment is preferably performed for 5 minutes or more and 36 hours or less, more preferably 4 hours or more and 14 hours or less.

A polymer compound that functions as a binder may be added to the positive electrode active material. Examples of such polymer compounds include polyvinylidene fluoride (PVdF), polyvinyl alcohol (PVA), and polypropylene carbonate (PPC). These polymer compounds are burned or oxidized in the heat treatment of this step, and the amount is reduced or burned away.

Furthermore, a pore former may be added to the positive electrode active material. A pore-forming material is a substance (such as a polymer compound or carbon powder) that serves as a template for voids. By adding the pore-forming material, the bulk density porosity of the active material portion 11 can be controlled. The pore-forming material is burned or oxidized in the heat treatment of this step and reduced in quantity. The average particle size of the pore-forming material is preferably 0.5 μm to 10 μm. The pore-forming material may include particles formed of a deliquescent material. The water generated in the surroundings by the deliquescence of the particles functions as a binder that binds the particulate lithium composite metal oxide together. Therefore, the shape of the compressed body can be maintained from the compression molding of the particulate positive electrode active material to the heat treatment.

The method for forming the porous active material portion 11 having a bulk density porosity of 40% to 60% is not limited to the press sintering method, and for example, a green sheet method may be used. Specifically, 1,4-dioxane as a solvent in which PPC as a binder (binding agent) is dissolved is mixed with LCO powder having an average particle size D50 of about 5 μm in the particle size distribution to form a slurry, and polyethylene terephthalate is obtained. A film (PET) substrate is coated using a fully automatic film applicator (manufactured by Cortec) to form a sheet.

The composition of the slurry at this time can take any value according to the desired thickness of the sheet and the performance of the coating apparatus. Further, auxiliary agents such as a dispersant, an antifoaming agent, and a pore-forming agent may be added to the slurry, if necessary.

A disk-shaped pellet having a diameter of, for example, 10 mm is obtained by punching out the sheet thus formed using a suitable punch. After degreasing the pellets at about 300° C., they are placed on a substrate made of, for example, magnesium oxide and fired using, for example, an electric muffle furnace. The sintering temperature is preferably 850° C. or higher and 875° C. or higher and 1000° C. or lower, which is lower than the melting point of LCO, which is the positive electrode active material. It is preferable that the firing time is, for example, 5 minutes or more and 36 hours or less. More preferably, it is 4 hours or more and 14 hours or less.

As a result, the LCO particles are sintered to obtain the active material portion 11, which is a porous sintered body having voids (inner cavities) therein. Then, the process proceeds to step S3.

In step S3, the porous active material portion 11 is impregnated with the electrolyte precursor solution prepared in step S1 and dried. Specifically, as shown in FIG. 7, the molded active material portion 11 is placed on the hot plate 85 with the substrate 84 interposed therebetween. The substrate 84 is made of a heat-resistant material such as magnesium oxide, and when heated by the hot plate 85, the hot plate 85 and the active material portion 11 are prevented from coming into direct contact with each other, thereby preventing deterioration of the active material portion 11 due to heating. It is.

A predetermined amount of the electrolyte precursor solution 60 is dripped from the nozzle 51 onto the active material portion 11 placed on the substrate 84 using, for example, a fixed quantity discharge device. Since the active material portion 11 is porous, the dropped electrolyte precursor solution 60 permeates into the active material portion 11 by capillary action. If the electrolyte precursor solution 60 remains on the surface of the active material portion 11 after dropping a predetermined amount of the electrolyte precursor solution 60, it is removed by wiping with a non-woven fabric or the like. Since the electrolyte precursor solution 60 contains the anionic surfactant 25, the wettability of the electrolyte precursor solution 60 with respect to the active material portion 11 is improved, and the electrolyte precursor solution efficiently fills the voids inside the active material portion 11. A solution 60 can be filled. Then, the solvent is dried by setting the temperature of the hot plate 85 to a temperature lower than 100° C. and at which the solvent can be evaporated. The set temperature and the drying time are, for example, about 15 minutes after the active material portion 11 reaches the set temperature, depending on the type of solvent. Next, by setting the temperature of the hot plate 85 to, for example, 360° C. and heating for 10 minutes, the carbohydrate contained in the electrolyte precursor solution 60 is burned and decomposed. Further, calcination is performed by setting the temperature of the hot plate 85 to, for example, 540° C., which is lower than the sintering temperature of the active material portion 11, and heating for 10 minutes. Then, it is slowly cooled until the temperature of the active material portion 11 reaches 50° C. or lower. As a result, the active material portion 11 is impregnated with the electrolyte precursor solution 60, dried, and temporarily baked, so that the various metal compounds contained in the electrolyte precursor solution 60 and the anionic surfactant 25 are mixed into the active material portion. It precipitates in the internal voids of 11.

By measuring the mass before and after impregnating the active material portion 11 with the electrolyte precursor solution 60 and drying and calcining, the filling rate of the electrolyte in the voids of the active material portion 11 is obtained. Based on the calculated filling rate of the electrolyte, step S3 is repeated until the filling rate reaches a desired state (for example, 70% or more). Then, the process proceeds to step S4.

In step S4, the active material portion 11 that has been impregnated with the electrolyte precursor solution 60, dried, and temporarily sintered is sintered (main sintered). Specifically, the calcined body of the active material portion 11 is placed in a heat-resistant crucible, such as magnesium oxide, and the crucible is placed in an electric muffle furnace, for example, and the LCO particles ( That is, firing is performed at a temperature of 900° C. to 1000° C. or less, which is lower than the melting point of the active material particles 11a) and higher than the temporary firing temperature, for example, for 8 hours. As a result, the various metal compounds filled in the voids in the calcined active material portion 11 are heat-treated to generate the crystalline first electrolyte portion 21 and the amorphous second electrolyte portion 22 . Further, as shown in FIG. 8, the anionic surfactant 25 (lithium dodecyl sulfate) adhering to the surface of the active material particles 11a is thermally decomposed to remove the hydrophobic group R, and the surface of the active material particles 11a is Lithium sulfate is produced. That is, in the voids of the active material portion 11, lithium sulfate is present between the active material particles 11a and the electrolyte (the first electrolyte portion 21 and the second electrolyte portion 22). In the present embodiment, the state in which the active material portion 11 and the electrolyte (the first electrolyte portion 21 and the second electrolyte portion 22) are combined after the main sintering is called a main sintered body 10p. Then, the process proceeds to step S5.

In step S5, the third electrolyte is further filled into the voids of the main sintered body 10p. Specifically, as shown in FIG. 9, first, the main sintered body 10p is arranged in the crucible 91. Then, as shown in FIG. The main sintered body 10 p is supported by support needles 92 provided on the bottom surface of the crucible 91 . The crucible 91 is made of magnesium oxide, for example, and the support needle 92 is made of gold (Au), for example. A solid third electrolyte 23p is arranged on the main fired body 10p. In this embodiment, the surface of the fired body 10p supported by the support needles 92 is the other surface 10a of the electrode composite 10 described above. On the other hand, the surface of the fired body 10p on which the third electrolyte 23p is arranged is referred to as one surface 10b.

In this embodiment, LCBO (Li _2+x C _1-x B _x O ₃ ) having a lower melting point than LLZrAO constituting the first electrolyte part 21 is used as the third electrolyte 23p. Since the melting point of LCBO is approximately 700° C., the crucible 91 is heated to approximately 800° C. in an atmosphere containing carbonic acid (CO ₂ ) gas to melt the third electrolyte 23p placed on the main fired body 10p. 23 m of melt was obtained. The melt 23m permeates into the porous main fired body 10p due to capillary action. After that, the crucible 91 is rapidly cooled to room temperature to solidify the permeated melt 23m. Inside the main sintered body 10p, the voids remaining between the sintered active material particles 11a are further filled with the melt 23m of the third electrolyte 23p to form the third electrolyte portion 23 after cooling. The surface of the main fired body 10p is also covered with the third electrolyte portion 23 by adjusting the amount of the melt 23m. As a result, the electrode composite 10 in which the electrolyte 20 (the first electrolyte portion 21, the second electrolyte portion 22, and the third electrolyte portion 23) is filled in the porous main sintered body 10p is completed. The average thickness of the electrode assembly 10 at this time is, for example, about 110 μm. Then, the process proceeds to step S6. Note that the ionic conductivity of LCBO is about 8.0×10 ⁻⁷ [S/cm], which is smaller than the ionic conductivity of the first electrolyte part 21 .

In step S6, as shown in FIG. 10, one surface 10b of the electrode assembly 10 filled with the electrolyte 20 is polished to expose the active material particles 11a. The surface where the active material particles 11a are exposed is the polished surface and corresponds to one surface 10c of the electrode assembly 10 shown in FIG. As a method for polishing the one surface 10b of the electrode assembly 10 in this way, for example, a chemical mechanical polishing process (CMP process) may be used. It should be noted that after filling the main fired body 10p with the melt 23m of the third electrolyte 23p in step S5, if the plurality of active material particles 11a are sufficiently exposed on the one surface 10b, the polishing treatment is not necessarily required. May not be implemented. That is, step S6 can be omitted.

After that, the electrolyte layer 24 is formed on the other surface 10 a of the electrode assembly 10 . In this embodiment, the electrolyte layer 24 is formed by sputtering the same LCBO as the third electrolyte portion 23 . The thickness of the electrolyte layer 24 may be 1.5 μm or more and 100 μm or less, and is set to 2.5 μm in this embodiment.

Next, a negative electrode 30 is formed by stacking on the electrolyte layer 24 . In this embodiment, the negative electrode 30 is formed by depositing metal lithium by a sputtering method. The thickness of the negative electrode 30 may be in the range of 50 nm or more and 100 μm or less, and in this embodiment, it is set to approximately 15 μm in consideration of the discharge capacity.

Next, as shown in FIG. 2 , a current collector 41 was formed so as to be in contact with one surface 10 c of the electrode assembly 10 , and a current collector 42 was formed so as to be in contact with the negative electrode 30 . In this embodiment, the current collectors 41 and 42 are formed by affixing a copper foil having a thickness of approximately 20 μm and crimping it. Thus, the lithium battery 100 is completed.

Next, more specific examples and comparative examples of the electrolyte precursor solution used to form the electrode assembly 10 will be given to explain the effect of using the electrolyte precursor solution of the example.

(Example 1)
The electrolyte precursor solution of Example 1 is an electrolyte precursor solution in which the metal compound constituting the crystalline first electrolyte portion 21 is represented by Li _6.7 La ₃ Zr _1.7 Nb _0.3 O ₁₂ (LLZrNbO), It contains lithium dodecyl sulfate (LDS) as a surfactant at a concentration five times the critical micelle concentration (CMC). The adjustment of the metal compound solution and the adjustment of the electrolyte precursor solution to be used will be described below.

[Preparation of lithium compound solution with concentration of 1 mol/kg]
0.6895 g of lithium nitrate 3N5 (manufactured by Kanto Kagaku Co., Ltd.) as a lithium source and 2-n-butoxyethanol (Kanto Kagaku Co., Ltd.) is weighed and placed on a hot plate with a stirrer function controlled at a stirrer speed of 300 rpm and a temperature of 170°C. Heat and stir for 30 minutes until the lithium nitrate is completely dissolved. After that, it is slowly cooled to room temperature to obtain a 1 mol/kg concentration lithium nitrate/2-n-butoxy ethanol solution.

[Preparation of lanthanum compound solution with a concentration of 1 mol/kg]
In a 20 mL Pyrex (trademark) reagent bottle containing a stir bar, 4.3301 g of lanthanum nitrate hexahydrate 4N (manufactured by Kanto Chemical Co., Ltd.) as a lanthanum source and 2-n-butoxyethanol ( 5.6699 g of Kanto Kagaku Co., Ltd.) is weighed and placed on a hot plate with a stirrer function controlled at a stirrer speed of 300 rpm and a temperature of 140°C. Heat and stir for 30 minutes until the lanthanum nitrate hexahydrate is completely dissolved. After that, it is slowly cooled to room temperature to obtain a 1 mol/kg concentration of lanthanum nitrate hexahydrate/2-n-butoxyethanol solution.

[Preparation of 1 mol/kg concentration zirconium compound solution]
In a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, 4.7960 g of zirconium tetrabutoxide 80 mass% butanol solution (manufactured by Gelest) as a zirconium source and 2-n-butoxyethanol (Kanto chemical) is weighed and placed on a stirrer with a stirrer rotation speed of 300 rpm. Stir for 10 minutes until the zirconium tetrabutoxide 80 mass % butanol solution and 2-n-butoxyethanol are completely mixed. After the stirring is completed, this is made into a zirconium tetrabutoxide/2-n-butoxy ethanol solution with a concentration of 1 mol/kg.

[Preparation of niobium compound solution with a concentration of 1 mol/kg]
3.1821 g of niobium pentaethoxide (manufactured by Kojundo Chemical Laboratory Co., Ltd.) as a niobium source and 2-n-butoxyethanol (Kanto Kagaku) is weighed 6.8179 g and placed on a stirrer with a stirrer rotation speed of 300 rpm. Stir for 10 minutes until the niobium pentaethoxide and 2-n-butoxyethanol are thoroughly mixed. After stirring is completed, this is made into a niobium pentaethoxide/2-n-butoxy ethanol solution with a concentration of 1 mol/kg.

[Preparation of an anionic surfactant solution with a concentration of 15 mmol/kg; 5 times the concentration of CMC]
0.0409 g of lithium dodecyl sulfate (LDS) (manufactured by ACROS ORGANICS) as an anionic surfactant and 9.9591 g of ethanol as a solvent are weighed into a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar. and placed on a hot plate with a stirrer function controlled at a stirrer speed of 300 rpm and a temperature of 165°C. Heat and stir for 30 minutes until the LDS is completely dissolved. After that, it is gradually cooled to room temperature to obtain an LDS/ethanol solution having a concentration of 15 mmol/kg.

[Adjustment of LLZrNbO solution]
In a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, 8.0400 g of a 1 mol/kg concentration of lithium nitrate/2-n-butoxy ethanol solution, 1 mol/kg concentration of lanthanum nitrate hexahydrate/2 - 3.0000 g of n-butoxy ethanol solution, 1.7000 g of 1 mol/kg concentration of zirconium tetrabutoxide/2-n-butoxy ethanol solution, and 1 mol/kg concentration of niobium pentaethoxide/2-n-butoxy ethanol solution. 0.3000 g and 1.0000 g of LDS/ethanol solution of 15 mmol/kg concentration are weighed and placed on a stirrer with a stirrer speed of 300 rpm.
Stir for 10 minutes until these mixtures are thoroughly mixed. After the stirring is finished _, the solution is made into a _{Li6.7La3Zr1.7Nb0.3O12} precursor ₍ + _LDS ; five times the concentration of CMC) solution with a concentration of ₁ mol/kg.

(Example 2)
In the electrolyte precursor solution of Example 2, the concentration of LDS as an anionic surfactant in Example 1 was 15 times the concentration of CMC, and other configurations were the same as in Example 1. . That is, for the lithium source (lithium nitrate), lanthanum source (lanthanum nitrate hexahydrate), zirconium source (zirconium tetrabutoxide), and niobium source (niobium pentaethoxide), the same procedure as in Example 1 was used. A 1 mol/kg concentration solution was prepared for each.

[Preparation of an anionic surfactant solution with a concentration of 45 mmol/kg; 15 times the concentration of CMC]
0.1225 g of LDS and 9.8775 g of ethanol as a solvent are weighed in a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, and the stirrer rotation speed is 300 rpm and the temperature is adjusted to 165 ° C. With a stirrer function Place on hot plate. Heat and stir for 30 minutes until the LDS is completely dissolved. After that, it is gradually cooled to room temperature to obtain an LDS/ethanol solution with a concentration of 45 mmol/kg.

[Preparation of LLZrNbO precursor solution]
In a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, 8.0400 g of a 1 mol/kg concentration of lithium nitrate/2-n-butoxy ethanol solution, 1 mol/kg concentration of lanthanum nitrate hexahydrate/2 - 3.0000 g of n-butoxy ethanol solution, 1.7000 g of 1 mol/kg concentration of zirconium tetrabutoxide/2-n-butoxy ethanol solution, and 1 mol/kg concentration of niobium pentaethoxide/2-n-butoxy ethanol solution. 0.3000 g and 1.0000 g of LDS/ethanol solution with a concentration of 45 mmol/kg are weighed and placed on a stirrer with a stirrer speed of 300 rpm. Stir for 10 minutes until these mixtures are thoroughly mixed. After the stirring is completed _, the solution is made into a _{Li6.7La3Zr1.7Nb0.3O12} precursor ₍ + _LDS ; ₁₅ times the concentration of CMC) solution with a concentration of 1 mol/kg.

(Example 3)
The electrolyte precursor solution of Example 3 is an electrolyte precursor solution in which the metal compound constituting the crystalline first electrolyte portion 21 is represented by Li _6.7 La ₃ Zr _1.2 Sb _0.4 Ta _0.4 O ₁₂ (LLZrSbTaO), It contains LDS as an anionic surfactant at a concentration ten times the critical micelle concentration (CMC). The adjustment of the metal compound solution and the adjustment of the electrolyte precursor solution to be used will be described below.

For the lithium source (lithium nitrate), lanthanum source (lanthanum nitrate hexahydrate), and zirconium source (zirconium tetrabutoxide), 1 mol/kg concentration solutions were prepared in the same manner as in Example 1.

[Preparation of antimony compound solution with concentration of 1 mol/kg]
2.5694 g of antimony triethoxide (manufactured by Kojundo Chemical Laboratory Co., Ltd.) as an antimony source and 2-n-butoxyethanol (Kanto Kagaku) is weighed 7.4306 g and placed on a stirrer with a stirrer rotation speed of 300 rpm. Stir for 10 minutes until the antimony triethoxide and 2-n-butoxyethanol are thoroughly mixed. After the stirring is completed, this is made into a 1 mol/kg antimony triethoxide/2-n-butoxy ethanol solution.

[Preparation of tantalum compound solution with a concentration of 1 mol/kg]
4.0625 g of tantalum pentaethoxide (manufactured by Kojundo Chemical Laboratory Co., Ltd.) as a tantalum source and 2-n-butoxyethanol (Kanto chemical) is weighed and placed on a stirrer with a stirrer rotation speed of 300 rpm. Stir for 10 minutes until the tantalum pentaethoxide and 2-n-butoxyethanol are thoroughly mixed. After stirring is completed, this is made into a tantalum pentaethoxide/2-n-butoxy ethanol solution with a concentration of 1 mol/kg.

[Preparation of an anionic surfactant solution with a concentration of 30 mmol/kg; 10 times the concentration of CMC]
0.0817 g of LDS as an anionic surfactant and 9.9183 g of ethanol as a solvent were weighed into a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, and stirred at a stirrer speed of 300 rpm and 165 ° C. Place on a hot plate with a stirrer function that is temperature-controlled. Heat and stir for 30 minutes until the LDS is completely dissolved. After that, it is gradually cooled to room temperature to obtain an LDS/ethanol solution with a concentration of 30 mmol/kg.

[Preparation of LLZrSbTaO precursor solution]
In a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, 7.4400 g of a 1 mol/kg concentration lithium nitrate/2-n-butoxyethanol solution, 1 mol/kg concentration lanthanum nitrate hexahydrate/2 -3.0000 g of n-butoxy ethanol solution, 1.2000 g of 1 mol/kg concentration of zirconium tetrabutoxide/2-n-butoxy ethanol solution, and 1 mol/kg concentration of antimony triethoxide/2-n-butoxy ethanol solution. 0.4000 g, 0.4000 g of a 1 mol/kg concentration of tantalum pentaethoxide/2-n-butoxy ethanol solution, and 1.0000 g of a 45 mmol/kg concentration of LDS/ethanol solution were weighed and stirred with a stirrer rotation speed of 300 rpm. put on top. Stir for 10 minutes until these mixtures are thoroughly mixed. After the stirring is completed, the solution is made _into a _{Li6.2La3Zr1.2Sb0.4Ta0.4O12 precursor (} + _LDS ; ₁₀ times the concentration of CMC) solution with a concentration of 1 mol/kg.

(Comparative example 1)
The electrolyte precursor solution of Comparative Example 1 is an electrolyte precursor solution in which the metal compound that constitutes the crystalline first electrolyte portion 21 is represented by Li _6.7 La ₃ Zr _1.7 Nb _0.3 O ₁₂ (LLZrNbO). It contains LDS as a surfactant at a concentration four times the critical micelle concentration (CMC). That is, the concentration of LDS is lowered compared to Example 1. The adjustment of the metal compound solution and the adjustment of the electrolyte precursor solution to be used will be described below.

For the lithium source (lithium nitrate), lanthanum source (lanthanum nitrate hexahydrate), zirconium source (zirconium tetrabutoxide), and niobium source (niobium pentaethoxide), 1 mol each in the same procedure as in Example 1 /kg concentration solution was prepared.

[Preparation of an anionic surfactant solution with a concentration of 12 mmol/kg; 4 times the concentration of CMC]
0.0327 g of LDS as an anionic surfactant and 9.9673 g of ethanol as a solvent were weighed into a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, and stirred at a stirrer speed of 300 rpm and 165 ° C. Place on a hot plate with a stirrer function that is temperature-controlled. Heat and stir for 30 minutes until the LDS is completely dissolved. After that, it is gradually cooled to room temperature to obtain an LDS/ethanol solution with a concentration of 12 mmol/kg.

[Preparation of LLZrNbO precursor solution]
In a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, 8.0400 g of a 1 mol/kg concentration of lithium nitrate/2-n-butoxy ethanol solution, 1 mol/kg concentration of lanthanum nitrate hexahydrate/2 - 3.0000 g of n-butoxy ethanol solution, 1.7000 g of 1 mol/kg concentration of zirconium tetrabutoxide/2-n-butoxy ethanol solution, and 1 mol/kg concentration of niobium pentaethoxide/2-n-butoxy ethanol solution. 0.3000 g and 1.0000 g of LDS/ethanol solution of 12 mmol/kg concentration are weighed and placed on a stirrer with a stirrer speed of 300 rpm. Stir for 10 minutes until these mixtures are thoroughly mixed. After the stirring is completed _, the solution is made into a _{Li6.7La3Zr1.7Nb0.3O12} precursor ₍ + _LDS ; four times the concentration of CMC) solution with a concentration of ₁ mol/kg.

(Comparative example 2)
The electrolyte precursor solution of Comparative Example 2 is an electrolyte precursor solution in which the metal compound constituting the crystalline first electrolyte portion 21 is represented by Li _6.7 La ₃ Zr _1.2 Sb _0.4 Ta _0.4 O ₁₂ (LLZrSbTaO), It contains LDS as an anionic surfactant at a concentration four times the critical micelle concentration (CMC). That is, the concentration of LDS is lowered compared to Example 3. The adjustment of the metal compound solution and the adjustment of the electrolyte precursor solution to be used will be described below.

For the lithium source (lithium nitrate), the lanthanum source (lanthanum nitrate hexahydrate), and the zirconium source (zirconium tetrabutoxide), each 1 mol/kg concentration solution was prepared by the same procedure as in Example 1, and antimony For the source (antimony triethoxide) and the tantalum source (tantalum pentaethoxide), 1 mol/kg concentration solutions are prepared in the same manner as in Example 3. As for the LDS/ethanol solution with a concentration of 12 mmol/kg, the one prepared in Comparative Example 1 is used.

[Preparation of LLZrSbTaO precursor solution]
7.4400 g of a 1 mol/kg concentration lithium nitrate/2-n-butoxy ethanol solution, 1 mol/kg concentration of lanthanum nitrate hexahydrate/2- 3.0000 g of n-butoxy ethanol solution, 1.2000 g of zirconium tetrabutoxide/2-n-butoxy ethanol solution of 1 mol/kg concentration, and 0 g of antimony triethoxide/2-n-butoxy ethanol solution of 1 mol/kg concentration. .4000 g, 0.4000 g of a 1 mol/kg concentration of tantalum pentaethoxide/2-n-butoxy ethanol solution and 1.0000 g of a 12 mmol/kg concentration of LDS/ethanol solution are weighed and placed on a stirrer at a stirrer speed of 300 rpm. put in Stir for 10 minutes until these mixtures are thoroughly mixed. After the stirring is completed, the solution is made _into a _{Li6.2La3Zr1.2Sb0.4Ta0.4O12 precursor (} + _LDS ; four times the concentration of CMC) solution with a concentration of ₁ mol/kg.

(Comparative Example 3)
Compared to the electrolyte precursor solution of Example 1, the electrolyte precursor solution of Comparative Example 3 does not contain an anionic surfactant. For the lithium source (lithium nitrate), lanthanum source (lanthanum nitrate hexahydrate), zirconium source (zirconium tetrabutoxide), and niobium source (niobium pentaethoxide), 1 mol each in the same procedure as in Example 1 /kg concentration solution was prepared.

[Preparation of LLZrNbO precursor solution]
In a 20 mL Pyrex (trademark) reagent bottle containing a stirrer bar, 8.0400 g of a 1 mol/kg concentration of lithium nitrate/2-n-butoxy ethanol solution, 1 mol/kg concentration of lanthanum nitrate hexahydrate/2 - 3.0000 g of n-butoxy ethanol solution, 1.7000 g of 1 mol/kg concentration of zirconium tetrabutoxide/2-n-butoxy ethanol solution, and 1 mol/kg concentration of niobium pentaethoxide/2-n-butoxy ethanol solution Weigh 0.3000 g of and place on a stirrer with a stirrer speed of 300 rpm. Stir for 10 minutes until these mixtures are thoroughly mixed. After the stirring is finished _, the solution is made into a _{Li6.7La3Zr1.7Nb0.3O12 precursor solution} with a concentration of ₁ mol/kg.

In each of the electrolyte precursor solutions of Examples 1 to 3 and Comparative Examples 1 to 3, the lithium nitrate/2-n-butoxyethanol solution as the lithium source was converted into Li ₂ CO ₃ in the air during firing. In consideration of scattering to the outside, the charged amount is set to 1.2 times the theoretical composition ratio. Further, since a 80% by mass solution of zirconium (tetravalent) butoxide in butanol is used as the zirconium source, the electrolyte precursor solution is adjusted to 1.25 times (1/0.8) the theoretical composition ratio.

[Production of electrode composite]
Using the electrolyte precursor solutions of Examples 1 to 3 and Comparative Examples 1 to 3, electrode composites were manufactured according to the electrode composite manufacturing method of the first embodiment. Specifically, first, using LCO particles with an average particle diameter D50 of 5 μm, an active material portion 11 having an outer shape of 10 mmφ, a thickness of 150 μm, and a bulk density porosity of about 50% was prepared.

Next, the active material portion 11 was placed on a hot plate 85 with the substrate 84 interposed therebetween, and 20 μL (microliter) of the electrolyte precursor solution of Example 1 was dropped to cause capillary action in the porous active material portion 11 . was used for impregnation (see FIG. 7). When the electrolyte precursor solution remained on the surface of the active material portion 11, it was wiped off with a Kikuwipe wiper S-200 (manufactured by Nippon Paper Crecia Co., Ltd.; trademark). Then, the temperature of the hot plate 85 was set to 87°C, and the solvent was dried for 15 minutes after reaching 87°C. Subsequently, the temperature setting of the hot plate 85 was set to 360° C., and combustion decomposition treatment of hydrocarbons contained in the electrolyte precursor solution was performed for 10 minutes after reaching 360° C. Further, the temperature of the hot plate 85 was set to 540°C, and calcination was performed for 10 minutes after reaching 540°C. Thereafter, the calcined body was slowly cooled until it reached 50° C. or lower.

After the above operation was performed 10 times, the mass of the obtained calcined body was measured. After that, the preliminarily fired body was fired at 900° C. for 8 hours using an electric muffle furnace to obtain a main fired body 10p. Then, the mass of the main fired body 10p was measured.

Based on the mass measurement result, the bulk density porosity of the main fired body 10p was obtained, and the powdery third electrolyte 23p composed of LCBO was weighed according to the bulk density porosity. The fired body 10p was placed in a crucible 91, the weighed third electrolyte 23p was placed on the fired body 10p, and heated in an atmosphere containing carbon dioxide to melt the third electrolyte 23p (see FIG. 9). ). By impregnating the main sintered body 10p with the melt 23m and cooling it, a crystalline first electrolyte portion 21, an amorphous second electrolyte portion 22, and a third amorphous electrolyte portion 23 are included in the voids of the active material portion 11. An electrode assembly of Example 1 filled with electrolyte 20 was obtained. The mass of the LCBO powder melted in Example 1 is approximately 5 mg.

Similarly, using the electrolyte precursor solutions of Examples 2, 3, and Comparative Examples 1 to 3, electrode composites were produced.

Regarding the ionic conductivity of lithium obtained by measuring the AC impedance of the electrode composites obtained using the electrolyte precursor solutions of Examples 1 to 3 and Comparative Examples 1 to 3, in the electrode composites The electrolyte bulk, grain boundary and total values are shown in Table 1 below. In the AC impedance measurement, in order to completely eliminate the electronic conductivity in the electrode composite and observe only the ion conductivity of lithium ions, the pellet-shaped electrode composite (active material portion 11, first electrolyte portion 21, second 2 including the electrolyte part 22) was formed by a sputtering method so that the film thickness of LCBO as an electrolyte was about 2 μm, and then metal lithium (Li) was similarly formed by a sputtering method to form an electrode. was used as a sample for each example and each comparative example.

As shown in Table 1 above, in Comparative Example 1 in which the concentration of the anionic surfactant (LDS) was four times the critical micelle concentration (CMC) and in Comparative Example 3 in which LDS was not added, the active material portion 11 and There is a grain boundary resistance between the electrolyte 20 and the bulk and grain boundary ionic conductivities, respectively. In Comparative Example 2, in which the concentration of LDS is four times that of CMC, the ionic conductivity of the bulk and the grain boundary was not obtained because LLZrSbTaO as the electrolyte was the crystalline first electrolyte part 21 and the amorphous first electrolyte part 21 . This is considered to be because it has two electrolyte parts 22 and behaves as if the grain boundary between the crystalline and amorphous phases has disappeared. Among Comparative Examples 1 to 3, Comparative Example 3, in which LDS was not added, had the lowest total ionic conductivity of 8.3×10 ⁻⁵ [S/cm].

On the other hand, in Examples 1 to 3 in which LDS was added at least 5 times as much as CMC, bulk and grain boundary ionic conductivity was not obtained, and compared to Comparative Examples 1 to 3, the total Ionic conductivity was obtained. This is because LDS is included in the electrolyte precursor solution at a concentration of 5 times or more that of CMC, and lithium sulfate derived from LDS is present between the active material portion 11 and the electrolyte, and the grain boundary resistance is lower than in Comparative Example 2. is considered to have become smaller.

Next, based on the lithium battery manufacturing method of the first embodiment, lithium batteries using the electrode composites of Examples 1 to 3 and Comparative Examples 1 to 3 were manufactured, and the battery characteristics were evaluated. The evaluation results are shown in Table 2 below. In addition, the battery characteristics were evaluated when the charge and discharge was performed at 100 μA (0.2 C), the discharge amount for the first charge amount was 90% or more, and the 10th discharge amount for the first discharge amount was 90%. ○ (suitable) if the condition is maintained, and x (unsuitable) otherwise.

As shown in Table 2 above, the lithium batteries using the electrode composites of Comparative Examples 1 to 3 were all evaluated as x (unsuitable) in the battery characteristics evaluation. Especially in Comparative Example 3 in which no anionic surfactant (LDS) was used, the initial discharge amount was 200 μA, which was less than half the charge amount, and the tenth discharge amount was half the initial discharge amount. there were.

On the other hand, in Example 1 in which the concentration of LDS was 5 times that of CMC, Example 2 in which it was 15 times that of CMC, and Example 3 in which it was 10 times that of CMC, the battery characteristics evaluation was good (preferred). That is, by using an electrolyte precursor solution containing an anionic surfactant (LDS) at a concentration of 5 to 15 times the critical micelle concentration (CMC), particles between the active material part 11 and the electrolyte 20 are formed. Field resistance can be reduced to form an electrode assembly 10 with excellent overall ionic conductivity. By using this electrode assembly 10 as a positive electrode, it is possible to provide and manufacture a lithium battery 100 having excellent battery characteristics.

In addition, in an electrolyte precursor solution containing an anionic surfactant (LDS) at a critical micelle concentration (CMC) of more than 15 times, most of the LDS is micellized. It became difficult to bind to the surface of 11a, and the function of an anionic surfactant (LDS) could not be fulfilled.

(Second embodiment)
<Electronic equipment>
Next, the electronic device of this embodiment will be described by taking a wearable device as an example. FIG. 11 is a perspective view showing the configuration of a wearable device as an electronic device according to the second embodiment.

As shown in FIG. 11, a wearable device 300 as an electronic device of the present embodiment is an information device that is worn on a human body, for example, a wrist WR, like a wristwatch, and is capable of obtaining information related to the human body. , a sensor 302 , a display unit 303 , a processing unit 304 and a battery 305 .

The band 301 has a belt-like shape using a flexible resin such as rubber so as to be in close contact with the wrist WR when worn, and has a connecting portion at the end of the band whose connecting position can be adjusted. .

The sensor 302 is, for example, an optical sensor, and is arranged on the inner surface side (wrist WR side) of the band 301 so as to touch the wrist WR when worn.

The display unit 303 is, for example, a light-receiving liquid crystal display device. are placed.

The processing unit 304 is, for example, an integrated circuit (IC), built in the band 301 and electrically connected to the sensor 302 and the display unit 303 . Based on the output from the sensor 302, the processing unit 304 performs arithmetic processing for measuring the pulse, blood sugar level, and the like. Also, it controls the display unit 303 to display the measurement results and the like.

The battery 305 is detachably incorporated in the band 301 as a power supply source that supplies power to the sensor 302, the display unit 303, the processing unit 304, and the like. As the battery 305, the lithium battery 100 of the first embodiment is used.

According to the wearable device 300 of the present embodiment, the sensor 302 electrically detects the wearer's pulse and blood sugar level information from the wrist WR. You can display your pulse, blood sugar level, etc. The display unit 303 can display not only the measurement result but also information indicating the state of the human body predicted from the measurement result, the time, and the like.

In addition, since the lithium battery 100 that is compact and has excellent charge/discharge characteristics is used as the battery 305, the wearable device 300 that is lightweight and thin and can withstand repeated use over a long period of time can be provided. . In addition, since the lithium battery 100 is a solid secondary battery, it can be used repeatedly by recharging, and there is no fear of electrolyte leakage, so that the wearable device 300 that can be used safely for a long period of time is provided. can.

In this embodiment, the wristwatch-type wearable device 300 is exemplified, but the wearable device 300 may be worn on the ankle, head, ear, waist, or the like, for example.

Also, the electronic device to which the lithium battery 100 as a power supply source is applied is not limited to the wearable device 300 . Examples include head-mounted displays, head-up displays, mobile phones, personal digital assistants, laptop computers, digital cameras, video cameras, music players, wireless headphones, and game machines. In addition, the present invention is applicable not only to such consumer equipment (for general consumers) but also to equipment for industrial use. Also, the electronic device of the present invention may have other functions such as a data communication function, a game function, a recording/playback function, and a dictionary function.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate within a range not contrary to the gist or idea of the invention that can be read from the scope of claims and the entire specification. , a method for producing an electrode assembly using the electrolyte precursor solution, an electrode assembly, a lithium battery to which the electrode assembly is applied, and an electronic device to which the lithium battery is applied are also included in the technical scope of the present invention. is. Various modifications other than the above-described embodiment can be considered. A modified example will be described below.

(Modification 1) The electrode assembly 10 of the first embodiment functioning as a positive electrode includes an active material portion 11, a first electrolyte portion 21, a second electrolyte portion 22, and a third electrolyte portion 23. However, the third electrolyte part 23 does not necessarily have to be included.

(Modification 2) According to the method for manufacturing the lithium battery 100 of the first embodiment, by adjusting the amount of the melt 23m of the third electrolyte 23p impregnated into the porous main fired body 10p, the electrode composite Electrolyte layer 24 may be formed on the other side 10 a of electrode assembly 10 at the same time, so electrode composite 10 may include electrolyte layer 24 .

(Modification 3) The configuration of the lithium battery containing the electrolyte formed using the electrolyte precursor solution of the first embodiment is limited to the lithium battery 100 having the electrode assembly 10 containing the electrolyte 20 in the lumen as the positive electrode. not. FIG. 12 is a schematic cross-sectional view showing the structure of a modified lithium battery. A modified lithium battery 200 shown in FIG. 12 has a positive electrode 210 , an electrolyte layer 220 and a negative electrode 230 sandwiched between a pair of current collectors 241 and 242 .

The electrolyte layer 220 includes at least a crystalline first electrolyte portion 221 and an amorphous second electrolyte portion 222. The solid electrolyte described in the first embodiment is used to form the first electrolyte. A portion 221 and a second electrolyte portion 222 can be configured. As a method for forming the electrolyte layer 220, for example, a sheet is formed using a slurry containing the material of the crystalline first electrolyte portion 221 by a green sheet method. The slurry contains, in addition to the material of the first electrolyte part 221, a binder, a pore-forming material, and the like. Then, a metal compound containing an element constituting the second electrolyte part 222, a solvent capable of dissolving the metal compound, and an anionic surfactant (for example, LDS) composed of a hydrophobic group in which a sulfate group and lithium are bonded are mixed. Prepare an electrolyte precursor solution containing: The pre-fired sheet is impregnated with the electrolyte precursor solution, dried and fired repeatedly, and then fired at a temperature of 900°C or more and less than 1000°C. Thereby, the amorphous second electrolyte portion 222 is filled between the particles of the particulate first electrolyte portion 221 inside, and the interface between the particulate first electrolyte portion 221 and the second electrolyte portion 222 is filled. A sheet-like electrolyte layer 220 in which lithium sulfate derived from an anionic surfactant (LDS) is present can be formed. The presence of lithium sulfate at the interface between the particulate first electrolyte portion 221 and the second electrolyte portion 222 promotes the dissociation of lithium ions. The ionic conductivity between the second electrolyte part 222 can be improved.

The positive electrode 210 is formed by stacking a positive electrode active material similar to the active material particles 11a constituting the active material portion 11 of the first embodiment on the sheet-like electrolyte layer 220 by, for example, a green sheet method. be able to. The negative electrode 230 can also be formed by laminating the negative electrode active material constituting the negative electrode 30 of the first embodiment on the sheet-like electrolyte layer 220 by, for example, a green sheet method. A battery cell in the form of a pellet is obtained by punching out a sheet-like laminate in which the positive electrode 210, the electrolyte layer 220, and the negative electrode 230 are laminated in this way into a desired size. Current collectors 241 and 242 may be provided for the battery cell.

The current collectors 241 and 242 are also made of, for example, 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 palladium (Pd) It is possible to use one kind of metal (single metal) selected from or an alloy composed of two or more kinds of metals selected from the metal group. Note that both of the current collectors 241 and 242 are not necessarily required, and either one of them may be provided.

According to the lithium battery 200 and the manufacturing method thereof, excellent ionic conductivity can be achieved in the electrolyte layer 220, so that a thin lithium battery 200 having excellent battery characteristics and mass productivity can be provided. Alternatively, it can be manufactured.

DESCRIPTION OF SYMBOLS 10... Electrode composite, 11... Active material part, 11a... Active material particle, 20... Electrolyte, 21... First electrolyte part, 22... Second electrolyte part, 23... Third electrolyte part, 23m... Third electrolyte melt , 23p... Third electrolyte, 24... Electrolyte layer as lithium reduction-resistant layer, 25... Anionic surfactant, 30... Negative electrode, 41, 42... Current collector, 60... Electrolyte precursor solution, 100, 200... Battery Lithium battery as a 300... Wearable device as an electronic device.

Claims (6)

an active material portion containing a plurality of active material particles and having voids therein;
an electrolyte comprising a crystalline first electrolyte portion and an amorphous second electrolyte portion;
each of the active material particles, the first electrolyte portion, and the second electrolyte portion contains lithium;
An electrode assembly, wherein the electrolyte is contained in the voids of the active material portion, and lithium sulfate is interposed between the surfaces of the active material particles and the electrolyte in the voids. The first electrolyte part is a metal compound represented by the following formula (1) having a garnet-type crystal structure and containing a metal A having a crystal radius of 78 pm or more,
2. The electrode assembly according to claim 1 , wherein said metal A is contained in said first electrolyte portion and said second electrolyte portion.
_{Li7 - xLa3} (Zr2 _{- xAx} )O12 (1)
0.05≦x≦0.6, and at least one of metal A is selected from Nb, Ta, and Sb. 3. The electrode assembly according to claim 1 , wherein the electrolyte includes an amorphous third electrolyte portion having a melting point lower than that of the first electrolyte portion and the second electrolyte portion. an electrode assembly according to any one of claims 1 to 3 ;
a current collector provided on one side of the electrode assembly so as to be in contact with the active material particles;
and a negative electrode provided on the other side of the electrode assembly. The negative electrode is made of metal lithium or an alloy containing lithium,
5. The battery according to claim 4 , comprising a lithium reduction resistant layer between said other surface of said electrode assembly and said negative electrode. An electronic device comprising the battery according to claim 4 or 5 .

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