JP2023049671A - All-solid-state battery, manufacturing method of all-solid-state battery, base powder, and production method of base powder - Google Patents

Abstract

To provide an all-solid-state battery in which a decrease in ionic conductivity can be suppressed while an amount of Ge is reduced, a manufacturing method of an all-solid-state battery, base powder, and a production method of base powder.SOLUTION: An all-solid-state battery includes a solid electrolyte layer, a first electrode layer which is provided on a first main surface of the solid electrolyte layer and contains an electrode active material, and a second electrode layer which is provided on a second main surface of the solid electrolyte layer and contains an electrode active material. A solid electrolyte that is a main component of the solid electrolyte layer has a structure represented by (Li1+x+(4-A)yAlxMyGe2-x-y(PO4)3), and is formed of a glass ceramic in which a portion of glass is crystallized. The A represents the valence of the M that is metal, and 0<A×y≤0.8 is satisfied.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an all-solid-state battery, an all-solid-state battery manufacturing method, a raw material powder, and a raw material powder manufacturing method.

Currently, lithium ion secondary batteries are used in various fields such as smartphones and automobiles. However, lithium-ion secondary batteries in practical use contain an organic electrolyte, which may cause electrolyte leakage, smoke, or fire. Therefore, development of an all-solid lithium ion secondary battery using an oxide solid electrolyte that is stable in the air is desired. NASICON-type solid electrolytes have been extensively studied as oxide solid electrolytes that have relatively high ionic conductivity and are stable in the atmosphere (see, for example, Patent Document 1).

JP 2018-73554 A

A glass solid electrolyte LAGP (Li _1+x Al _x Ge _2-x (PO ₄ ) ₃ ), which deposits crystals having a NASICON-type crystal structure by being crystallized by heat treatment, can be sintered at a low temperature. In addition, the LAGP sintered body exhibits a high ion conductivity (approximately 10 ⁻⁴ S/cm) at room temperature. However, LAGP suffers from the high cost of Ge. Moreover, it is desirable to be able to control the sintering temperature when sintering the aforementioned glass solid electrolyte together with a plurality of other materials. A technique is required that can control the sintering temperature while reducing the amount of Ge. However, if Ge is partially substituted with another element in order to reduce the amount of Ge, the ionic conductivity may decrease.

The present invention has been made in view of the above problems, and an all-solid battery that can suppress a decrease in ion conductivity while reducing the amount of Ge, a method for manufacturing an all-solid battery, a raw material powder, and a raw material powder. The object is to provide a manufacturing method.

An all-solid-state battery according to the present invention includes a solid electrolyte layer, a first electrode layer provided on a first main surface of the solid electrolyte layer, a first electrode layer containing an electrode active material, and a second main surface of the solid electrolyte layer. and a second electrode layer containing an electrode active material, wherein the solid electrolyte, which is the main component of the solid electrolyte layer, is (Li _{1+x+(4-A) y} Al _x M _y Ge _2-x-y (PO ₄ ) ₃ ) A solid electrolyte made of a glass-ceramic in which a part of the glass is crystallized, wherein A is the valence of the metal M, and 0<A×y≦0.8 It is characterized by

In the all-solid-state battery, M may be Zr, Sn, or Ti.

In the all-solid-state battery, M may be Co, Mg, or Ca.

A method for manufacturing an all-solid-state battery according to the present invention includes a green sheet containing a solid electrolyte powder, a first electrode layer paste coating material formed on a first main surface of the green sheet and containing an electrode active material, and the green sheet a paste coating for a second electrode layer formed on the second main surface of and containing an electrode active material; and a step of firing the laminate, wherein the solid electrolyte powder is , (Li _{1+x+(4-A) y} Al _x M _y Ge _2-xy (PO ₄ ) ₃ ), wherein A is the valence of M, which is a metal. , 0<A×y≦0.8.

The raw material powder according to the present invention is a raw material powder containing a solid electrolyte powder, wherein the solid electrolyte powder is (Li _{1+x+(4-A) y} Al _x M _y Ge _2-xy (PO ₄ ) ₃ ) wherein A is the valence of M, which is a metal, and 0<A×y≦0.8.

The method for producing a raw material powder according to the present invention uses a raw material containing Li, Al, and metals M, Ge, P, and O by a melt quenching method (Li _{1+x+ (4-A) y} Al _x M _y Ge _2-xy (PO ₄ ) ₃ ), wherein A is the valence of M, and 0<A×y≦0 .8.

Advantageous Effects of Invention According to the present invention, it is possible to provide an all-solid-state battery, a method for manufacturing an all-solid-state battery, a raw material powder, and a method for manufacturing a raw material powder that can suppress a decrease in ionic conductivity while reducing the amount of Ge. .

1 is a schematic cross-sectional view showing the basic structure of an all-solid-state battery; FIG. 1 is a schematic cross-sectional view of an all-solid-state battery according to an embodiment; FIG. FIG. 4 is a schematic cross-sectional view of another all-solid-state battery; It is a figure which illustrates the flow of the manufacturing method of an all-solid-state battery. (a) and (b) are figures which illustrate a lamination process.

Hereinafter, embodiments will be described with reference to the drawings.

(embodiment)
FIG. 1 is a schematic cross-sectional view showing the basic structure of an all-solid-state battery 100. FIG. As illustrated in FIG. 1, the all-solid-state battery 100 has a structure in which a solid electrolyte layer 30 is sandwiched between a first internal electrode 10 (first electrode layer) and a second internal electrode 20 (second electrode layer). have. First internal electrode 10 is formed on the first main surface of solid electrolyte layer 30 . The second internal electrode 20 is formed on the second main surface of the solid electrolyte layer 30 .

When the all-solid battery 100 is used as a secondary battery, one of the first internal electrode 10 and the second internal electrode 20 is used as a positive electrode, and the other is used as a negative electrode. In this embodiment, as an example, the first internal electrode 10 is used as a positive electrode layer, and the second internal electrode 20 is used as a negative electrode layer.

The solid electrolyte layer 30 is mainly composed of a solid electrolyte having ionic conductivity. The solid electrolyte, which is the main component of the solid electrolyte layer 30, is an oxide-based solid electrolyte having lithium ion conductivity, and is a phosphate-based solid electrolyte having a NASICON structure. A phosphate-based solid electrolyte having a NASICON structure has properties of high electrical conductivity and stability in the air. A phosphate-based solid electrolyte is a phosphate containing lithium. In the present embodiment, the solid electrolyte serving as the main component of the solid electrolyte layer 30 is a glass solid electrolyte LAGP (Li _1+x Al _x Ge _{2-x )} that precipitates crystals having a NASICON-type crystal structure by being crystallized by heat treatment. ( _PO4 ) ₃ is used.

The first internal electrode 10 used as a positive electrode contains a material having an olivine crystal structure as an electrode active material. The second internal electrode 20 also preferably contains the electrode active material. Examples of such electrode active materials include phosphates containing transition metals and lithium. The olivine type crystal structure is a crystal of natural olivine and can be identified by X-ray diffraction.

As a typical example of an electrode active material having an olivine-type crystal structure, _LiCoPO4 containing Co can be used. A phosphate or the like in which the transition metal Co is replaced in this chemical formula can also be used. Here, the ratio of Li and _PO4 can vary depending on the valence. Co, Mn, Fe, Ni, etc. are preferably used as transition metals.

An electrode active material having an olivine-type crystal structure acts as a positive electrode active material in the first internal electrode 10 that acts as a positive electrode. For example, when only the first internal electrode 10 contains an electrode active material having an olivine crystal structure, the electrode active material acts as a positive electrode active material. When the second internal electrode 20 also contains an electrode active material having an olivine-type crystal structure, the second internal electrode 20 acting as a negative electrode has not been completely clarified, but the negative electrode active material is Effects such as an increase in discharge capacity and an increase in operating potential associated with discharge, which are presumed to be based on the formation of a partial solid solution state with a substance, are exerted.

When both the first internal electrode 10 and the second internal electrode 20 contain an electrode active material having an olivine crystal structure, each electrode active material preferably contains the same or different Contains good transition metals. “They may be the same or different” means that the electrode active materials contained in the first internal electrode 10 and the second internal electrode 20 may contain the same type of transition metal, or may contain different types of transition metals. of transition metals may be included. The first internal electrode 10 and the second internal electrode 20 may contain only one kind of transition metal, or may contain two or more kinds of transition metals. Preferably, the first internal electrode 10 and the second internal electrode 20 contain transition metals of the same type. More preferably, both electrodes contain the same electrode active material in chemical composition. When the first internal electrode 10 and the second internal electrode 20 contain the same transition metal or the electrode active material with the same composition, the compositional similarity of both internal electrode layers increases. Even if the polarity of the terminal of the all-solid-state battery 100 is reversed, depending on the application, it can withstand actual use without malfunction.

The second internal electrode 20 contains a negative electrode active material. By including the negative electrode active material in only one electrode, it becomes clear that the one electrode acts as a negative electrode and the other electrode acts as a positive electrode. Both electrodes may contain a known negative electrode active material. Regarding the negative electrode active material of the electrode, prior art in secondary batteries can be appropriately referred to, for example, titanium oxide, lithium titanium composite oxide, lithium titanium composite phosphate, carbon, compounds such as vanadium lithium phosphate is mentioned.

In the production of the first internal electrode 10 and the second internal electrode 20, in addition to these electrode active materials, a solid electrolyte having ion conductivity, a conductive material (a conductive aid), and the like are added. For these members, an internal electrode paste can be obtained by uniformly dispersing a binder and a plasticizer in water or an organic solvent. A carbon material or the like may be contained as a conductive aid. A metal may be contained as a conductive aid. Examples of the metal of the conductive aid include Pd, Ni, Cu, Fe, and alloys containing these. The solid electrolyte contained in the first internal electrode 10 and the second internal electrode 20 can be the same as the solid electrolyte that is the main component of the solid electrolyte layer 30, for example.

A solid electrolyte (LAGP) made of Li—Al—Ge—PO ₄ -based glass-ceramics (glass-ceramics in which glass is partially crystallized) used as a solid electrolyte that is the main component of the solid electrolyte layer 30 is, for example, (Li _1+x Al _x Ge _2-x (PO ₄ ) ₃ ). LAGP is a glass solid electrolyte that can be sintered at low temperatures. Also, the sintered body of LAGP exhibits a high ion conductivity (approximately 10 ⁻⁴ S/cm) at room temperature. However, since LAGP contains high-cost Ge, the cost of the all-solid-state battery 100 is increased. Therefore, it is desirable to reduce the amount of Ge.

Also, the solid electrolyte layer 30 is fired simultaneously with the first internal electrode 10 and the second internal electrode 20 . If the difference between the sintering temperature of the solid electrolyte layer 30 and the sintering temperature of the first internal electrode 10 and the second internal electrode 20 is large, cracks and delamination may occur. Therefore, it is desired that the sintering temperature of the solid electrolyte layer 30 can be controlled.

In view of the above, there is a demand for a technique capable of controlling the sintering temperature of the solid electrolyte layer 30 while reducing the amount of Ge. However, when trying to partially replace Ge with another element in order to reduce the amount of Ge, the ionic conductivity of the solid electrolyte layer 30 may decrease.

Therefore, the solid electrolyte, which is the main component of the solid electrolyte layer 30 according to the present embodiment, has a configuration in which the amount of Ge is reduced while suppressing the decrease in ionic conductivity. Specifically, the solid electrolyte that is the main component of the solid electrolyte layer 30 has a structure of LAGP (Li _1+x+(4-A)y Al _x M _y Ge _2-xy (PO ₄ ) ₃ ). there is A is the valence of M; By setting 0<y, the amount of Ge can be reduced.

By using a tetravalent metal as M, the sintering temperature of the solid electrolyte that is the main component of the solid electrolyte layer 30 can be controlled to a high temperature side. This is because the tetravalent metals other than Ge have a high liquid phase formation temperature due to the high stability of the Li-Al-MPO bond, so the sintering temperature is higher than that of LAGP. It is presumed that this is because However, when the substitution amount y of Ge increases, vitrification may be inhibited and sufficient ionic conductivity may not be obtained. Therefore, an upper limit is set for the substitution amount y of Ge. In this embodiment, if M is a tetravalent metal, 0<y≦0.2.

When a tetravalent metal is used as M, from the viewpoint of reducing cost by increasing the substitution amount y of Ge, the substitution amount y of Ge is preferably 0.03 or more, and is 0.05 or more. is more preferable, and 0.10 or more is even more preferable.

On the other hand, when a tetravalent metal is used as M, the substitution amount y of Ge is preferably 0.18 or less, more preferably 0.15 or less, from the viewpoint of obtaining sufficient ionic conductivity. .

As the tetravalent metal M, for example, Zr, Sn, Ti or the like can be used. Among these, Zr can change the sintering temperature to a higher temperature even in a small amount. Therefore, it is preferable to use Zr as M of the tetravalent metal.

By using a divalent metal as M, the sintering temperature of the solid electrolyte, which is the main component of the solid electrolyte layer 30, can be controlled to the low temperature side. This is because the sintering temperature is lower than that of LAGP because the liquid phase formation temperature is low due to the low stability of the Li—Al—M—P—O bond in divalent metals. presumed to be. However, when the substitution amount y of Ge increases, vitrification may be inhibited and sufficient ionic conductivity may not be obtained. Therefore, an upper limit is set for the substitution amount y of Ge. In this embodiment, if M is a divalent metal, 0<y≦0.4. Co, Mg, Ca, etc. can be used as M of a bivalent metal, for example.

In the case of using a divalent metal as M, from the viewpoint of reducing the cost by increasing the substitution amount y of Ge, the substitution amount y of Ge is preferably 0.05 or more, and is 0.10 or more. is more preferable, and 0.20 or more is even more preferable.

On the other hand, when a divalent metal is used as M, the substitution amount y of Ge is preferably 0.35 or less, more preferably 0.3 or less, from the viewpoint of obtaining sufficient ionic conductivity. .

The difference in the preferred upper limit of the Ge substitution amount y between when the valence of M is tetravalent and when it is divalent is due to the stability of Li—Al—M—P—O. This is because divalent is easier to vitrify, and tetravalent cannot be vitrified with a smaller amount of substitution.

From the above description, the relationship 0<A×y≦0.8 can be derived. In (Li _{1+x+(4-A) y} Al _x M _y Ge _2-x-y (PO ₄ ) ₃ ), x is, for example, 0.2 or more and 0.8 or less, and 0.3 or more and 0.3 or more. It is preferably 0.7 or less, more preferably 0.4 or more and 0.6 or less.

FIG. 2 is a schematic cross-sectional view of a stacked all-solid-state battery 100a in which a plurality of battery units are stacked. The all-solid-state battery 100a includes a laminated chip 60 having a substantially rectangular parallelepiped shape. In the laminated chip 60, the first external electrode 40a and the second external electrode 40b are provided so as to be in contact with two side surfaces of the four surfaces other than the top surface and the bottom surface of the stacking direction end. The two side surfaces may be two adjacent side surfaces or two side surfaces facing each other. In the present embodiment, the first external electrode 40a and the second external electrode 40b are provided so as to be in contact with two side surfaces (hereinafter referred to as two end surfaces) facing each other.

In the following description, those having the same composition range, the same thickness range, and the same particle size distribution range as those of the all-solid-state battery 100 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the all-solid-state battery 100a, a plurality of first internal electrodes 10 and a plurality of second internal electrodes 20 are alternately stacked with solid electrolyte layers 30 interposed therebetween. Edges of the plurality of first internal electrodes 10 are exposed on the first end surface of the laminated chip 60 and are not exposed on the second end surface. Edges of the plurality of second internal electrodes 20 are exposed on the second end surface of the laminated chip 60 and are not exposed on the first end surface. Thereby, the first internal electrode 10 and the second internal electrode 20 are alternately connected to the first external electrode 40a and the second external electrode 40b. The solid electrolyte layer 30 extends from the first external electrode 40a to the second external electrode 40b. Thus, the all-solid-state battery 100a has a structure in which a plurality of battery units are stacked.

A cover layer 50 is laminated on the upper surface of the laminated structure of the first internal electrode 10, the solid electrolyte layer 30 and the second internal electrode 20 (the upper surface of the uppermost first internal electrode 10 in the example of FIG. 2). A cover layer 50 is also laminated on the lower surface of the laminated structure (in the example of FIG. 2, the lower surface of the lowermost first internal electrode 10). The cover layer 50 is mainly composed of, for example, an inorganic material containing Al, Si, Zr, Ti (eg, Al ₂ O ₃ , SiO ₂ , ZrO ₂ , TiO _{2 ,} etc.). The cover layer 50 may contain a solid electrolyte, which is the main component of the solid electrolyte layer 30, as a main component.

The first internal electrode 10 and the second internal electrode 20 may have collector layers. For example, as illustrated in FIG. 3, the first collector layer 11 may be provided inside the first internal electrode 10 . Also, a second collector layer 21 may be provided in the second internal electrode 20 . The first current collector layer 11 and the second current collector layer 21 are mainly composed of a conductive material. For example, metal, carbon, or the like can be used as the conductive material of the first current collector layer 11 and the second current collector layer 21 . By connecting the first collector layer 11 to the first external electrode 40a and connecting the second collector layer 21 to the second external electrode 40b, the current collection efficiency is improved.

Next, a method for manufacturing the all-solid-state battery 100a illustrated in FIG. 2 will be described. FIG. 4 is a diagram illustrating the flow of the method for manufacturing the all-solid-state battery 100a.

(Process for preparing raw material powder for solid electrolyte layer)
First, raw material powder for the solid electrolyte layer 30 described above is prepared. For example, by mixing a raw material containing Li, Al, a divalent or tetravalent metal M, Ge, P, and O, an additive, and the like, and using a melt quenching method or the like, a solid electrolyte A raw material powder (glass solid electrolyte) for the layer can be produced. By using a melting and quenching method or the like, the solid electrolyte that is the main component of the solid electrolyte layer 30 can be vitrified. By dry pulverizing the obtained raw material powder, it is possible to adjust to a desired average particle size. For example, a planetary ball mill using 5 mmφ ZrO ₂ balls is used to adjust the desired average particle size.

The raw material powder has a structure of LAGP (Li _1+x+(4-A)y Al _x M _y Ge _2-xy (PO ₄ ) ₃ ). A is the valence of M, and 0<A×y≦0.8.

(Process for preparing raw material powder for cover layer)
First, raw material powder of ceramics that constitutes the cover layer 50 is prepared. For example, raw material powder for the cover layer can be produced by mixing raw materials, additives, and the like and using a solid-phase synthesis method or the like. By dry pulverizing the obtained raw material powder, it is possible to adjust to a desired average particle size. For example, a planetary ball mill using 5 mmφ ZrO ₂ balls is used to adjust the desired average particle size.

(Internal electrode paste preparation process)
Next, an internal electrode paste for producing the above-described first internal electrode 10 and second internal electrode 20 is produced. For example, an internal electrode paste can be obtained by uniformly dispersing a conductive aid, an electrode active material, a solid electrolyte material, a sintering aid, a binder, a plasticizer, and the like in water or an organic solvent. As the solid electrolyte material, the solid electrolyte paste described above may be used. A carbon material or the like is used as the conductive aid. A metal may be used as the conductive aid. Examples of the metal of the conductive aid include Pd, Ni, Cu, Fe, and alloys containing these. Pd, Ni, Cu, Fe, alloys containing these, and various carbon materials may also be used. If the compositions of the first internal electrode 10 and the second internal electrode 20 are different, the respective internal electrode pastes may be prepared separately.

Examples of sintering aids for internal electrode paste include Li—B—O compounds, Li—Si—O compounds, Li—C—O compounds, Li—S—O compounds, Li—P—O Any one or a plurality of glass components such as glass compounds are included.

(External electrode paste preparation process)
Next, an external electrode paste for producing the first external electrode 40a and the second external electrode 40b is prepared. For example, an external electrode paste can be obtained by uniformly dispersing a conductive material, a glass frit, a binder, a plasticizer, and the like in water or an organic solvent.

(Solid electrolyte green sheet manufacturing process)
A solid electrolyte slurry having a desired average particle size is prepared by uniformly dispersing the raw material powder for the solid electrolyte layer in an aqueous solvent or an organic solvent together with a binder, a dispersant, a plasticizer, etc., followed by wet pulverization. get At this time, a bead mill, a wet jet mill, various kneaders, a high-pressure homogenizer, or the like can be used, and it is preferable to use a bead mill from the viewpoint of being able to simultaneously adjust the particle size distribution and disperse. A binder is added to the obtained solid electrolyte slurry to obtain a solid electrolyte paste. By applying the obtained solid electrolyte paste, the solid electrolyte green sheet 51 can be produced. The coating method is not particularly limited, and a slot die method, a reverse coating method, a gravure coating method, a bar coating method, a doctor blade method, or the like can be used. The particle size distribution after wet pulverization can be measured, for example, using a laser diffraction measurement device using a laser diffraction scattering method.

(Lamination process)
As illustrated in FIG. 5( a ), an internal electrode paste 52 is printed on one surface of a solid electrolyte green sheet 51 . A reverse pattern 53 is printed on a region of the solid electrolyte green sheet 51 where the internal electrode paste 52 is not printed. As the reverse pattern 53, the same one as the solid electrolyte green sheet 51 can be used. A plurality of solid electrolyte green sheets 51 after printing are alternately shifted and laminated. As illustrated in FIG. 5B, the laminate is obtained by crimping the cover sheets 54 from above and below in the lamination direction. In this case, in the laminate, the internal electrode paste 52 for the first internal electrode 10 is exposed on one end surface, and the internal electrode paste 52 for the second internal electrode 20 is exposed on the other end surface. A laminate having a substantially rectangular parallelepiped shape is obtained. The cover sheet 54 can be formed by coating the raw material powder for the cover layer in the same manner as in the solid electrolyte green sheet production process. The cover sheet 54 is formed thicker than the solid electrolyte green sheet 51 . The thickness may be increased during coating, or may be increased by stacking a plurality of coated sheets.

Next, the external electrode paste 55 is applied to each of the two end faces by a dipping method or the like and dried. Thereby, a molding for forming the all-solid-state battery 100a is obtained.

(Baking process)
Next, the obtained laminate is fired. The firing conditions are oxidizing atmosphere or non-oxidizing atmosphere, and the maximum temperature is preferably 400° C. to 1000° C., more preferably 500° C. to 900° C., without any particular limitation. A step of holding below the maximum temperature in an oxidizing atmosphere may be provided to sufficiently remove the binder until the maximum temperature is reached. In order to reduce process costs, it is desirable to bake at as low a temperature as possible. After firing, reoxidation treatment may be performed. Through the above steps, the all-solid-state battery 100a is produced.

Note that the internal electrode paste, the current collector paste containing a conductive material, and the internal electrode paste are sequentially laminated to form current collector layers in the first internal electrode 10 and the second internal electrode 20. can be formed.

All-solid-state batteries were produced according to the embodiments, and their characteristics were examined.

(Example 1)
Li ₂ CO ₃ , Al ₂ O ₃ , GeO ₂ , NH ₄ H ₂ PO ₄ and ZrO ₂ in a molar ratio of Li:Al:Ge:Zr:P=1.5:0.5:1.45:0. 05:3.0, melted at 1300° C. in a platinum crucible, and quenched. The substitution amount y of Ge is 0.05. The solid obtained was in a transparent glassy state. When this was pulverized into powder, pelletized and sintered, the sintering temperature was 10° C. higher than that without substitution, and it was confirmed that a solid electrolyte sintered body exhibiting ionic conductivity was obtained.

(Example 2)
A molten and quenched solid was obtained in the same manner as in Example 1 except that the molar ratio of Li:Al:Ge:Zr:P=1.5:0.5:1.4:0.1:3.0. The substitution amount y of Ge is 0.10. The solid obtained was in a transparent glassy state. When this was pulverized into powder, pelletized and sintered, the sintering temperature was 15° C. higher than that without replacement, and it was confirmed that a solid electrolyte sintered body exhibiting ionic conductivity was obtained.

(Example 3)
A molten and quenched solid was obtained in the same manner as in Example 1 except that the molar ratio of Li:Al:Ge:Zr:P=1.5:0.5:1.3:0.2:3.0. The substitution amount y of Ge is 0.20. The obtained solid was in a transparent glassy state. When this was pulverized into powder, pelletized and fired, the sintering temperature was 20° C. higher than that without replacement, and it was confirmed that a solid electrolyte sintered body exhibiting ion conduction was obtained.

(Comparative example 1)
A molten and quenched solid was obtained in the same manner as in Example 1, except that the molar ratio of Li:Al:Ge:Zr:P=1.5:0.5:1.25:0.25:3.0. The substitution amount y of Ge is 0.25. The obtained solid was devitrified and partially crystallized. When this was pulverized into powder, pelletized and fired, the sintering temperature was 30° C. higher than that without replacement, and the sinterability was insufficient, resulting in a solid electrolyte sintered body with low ion conductivity. confirmed to be

(Example 4)
A melt-quenched solid was obtained in the same manner as in Example 3, except that _ZrO2 was _SnO2 . The substitution amount y of Ge is 0.20. The solid obtained was in a transparent glassy state. This was pulverized into powder, the sintering temperature became 50° C. higher than that without substitution, and when pelletized and fired, it was confirmed that a solid electrolyte sintered body exhibiting ion conduction was obtained.

(Comparative example 2)
A molten and quenched solid was obtained in the same manner as in Example 4 except that the molar ratio of Li:Al:Ge:Sn:P=1.5:0.5:1.25:0.25:3.0. The substitution amount y of Ge is 0.25. The obtained solid was devitrified and partially crystallized. When this was pulverized into powder, pelletized and fired, the sintering temperature was 60° C. higher than that without replacement, and the sinterability was insufficient, resulting in a solid electrolyte sintered body with low ion conductivity. confirmed to be

(Example 5)
A melt-quenched solid was obtained in the same manner as in Example 3, except that TiO ₂ was used instead of ZrO ₂ . The substitution amount y of Ge is 0.20. The obtained solid was in a transparent glassy state. This was pulverized into powder, the sintering temperature became 20° C. higher than that without substitution, and when pelletized and fired, it was confirmed that a solid electrolyte sintered body exhibiting ion conduction was obtained.

(Comparative Example 3)
A molten and quenched solid was obtained in the same manner as in Example 5 except that the molar ratio of Li:Al:Ge:Ti:P=1.5:0.5:1.25:0.25:3.0. The substitution amount y of Ge is 0.25. The obtained solid was devitrified and partially crystallized. When this was pulverized into powder, pelletized and fired, the sintering temperature was 30° C. higher than that without replacement, and the sinterability was insufficient, resulting in a solid electrolyte sintered body with low ion conductivity. confirmed to be

(Example 6)
A melt-quenched solid was obtained in the same manner as in Example 3, except that ZrO ₂ was replaced by Co ₃ O ₄ . The substitution amount y of Ge is 0.20. The obtained solid was in a transparent glassy state. It was confirmed that when this was pulverized into powder, the sintering temperature became 20° C. lower than that without replacement, and pelletized and fired, a solid electrolyte sintered body exhibiting ion conduction was obtained.

(Example 7)
A molten and quenched solid was obtained in the same manner as in Example 6 except that the molar ratio of Li:Al:Ge:Co:P=1.5:0.5:1.3:0.4:3.0. The substitution amount y of Ge is 0.40. The obtained solid was in a transparent glassy state. When this was pulverized into powder, pelletized and sintered, the sintering temperature was 30° C. lower than that without replacement, and it was confirmed that a solid electrolyte sintered body exhibiting ionic conductivity was obtained.

(Comparative Example 4)
A molten and quenched solid was obtained in the same manner as in Example 6 except that the molar ratio of Li:Al:Ge:Co:P=1.5:0.5:1.25:0.5:3.0. The substitution amount y of Ge is 0.50. The obtained solid was devitrified and partially crystallized. When this was pulverized into powder, pelletized and fired, the sintering temperature was 30°C lower than that of the solid electrolyte sintered body without replacement, indicating insufficient sinterability and low ion conductivity. confirmed to be

(Example 8)
A molten quenched solid was obtained as in Example 7, except that _ZrO2 was MgO. The substitution amount y of Ge is 0.40. The obtained solid was in a transparent glassy state. This was pulverized into powder, the sintering temperature became 10° C. lower than that without substitution, and when pelletized and fired, it was confirmed that a solid electrolyte sintered body exhibiting ion conduction was obtained.

(Comparative Example 5)
A molten and quenched solid was obtained in the same manner as in Example 8 except that the molar ratio of Li:Al:Ge:Mg:P=1.5:0.5:1.25:0.5:3.0. The substitution amount y of Ge is 0.50. The obtained solid was devitrified and partially crystallized. When this was pulverized into powder, pelletized and fired, the sintering temperature was 10°C lower than that of the solid electrolyte sintered body without replacement, and the sinterability was insufficient, resulting in a solid electrolyte sintered body with low ion conductivity. confirmed to be

(Example 9)
A melt-quenched solid was obtained in the same manner as in Example 7, except that CaO was used instead of _ZrO2 . The substitution amount y of Ge is 0.40. The obtained solid was in a transparent glassy state. When this was pulverized into powder, pelletized and fired, it was confirmed that the sintering temperature was 5° C. lower than that without substitution, and that a solid electrolyte sintered body exhibiting ionic conductivity was obtained.

(Comparative Example 6)
A molten and quenched solid was obtained in the same manner as in Example 9 except that the molar ratio of Li:Al:Ge:Mg:P=1.5:0.5:1.25:0.5:3.0. The substitution amount y of Ge is 0.50. The obtained solid was devitrified and partially crystallized. When this was pulverized into powder, pelletized and fired, the sintering temperature was 10°C lower than that of the solid electrolyte sintered body without replacement, and the sinterability was insufficient, resulting in a solid electrolyte sintered body with low ion conductivity. confirmed to be

Table 1 shows the results of Examples 1-9 and Comparative Examples 1-6. From the results of Examples 1 to 5 and Comparative Examples 1 to 3, it can be seen that the sintering temperature can be controlled to a high temperature side by substituting part of Ge with a tetravalent metal. However, in Comparative Examples 1 to 3, vitrification was insufficient and sufficient ionic conductivity was not obtained. It is considered that this is because the Ge substitution amount y exceeded 0.2. On the other hand, in Examples 1 to 5, sufficient vitrification and sufficient ionic conductivity were obtained. It is considered that this is because the Ge substitution amount y is set to 0.2 or less.

From the results of Examples 6 to 9 and Comparative Examples 4 to 6, it can be seen that the sintering temperature can be controlled to a lower temperature by substituting part of Ge with a divalent metal. However, in Comparative Examples 4 to 6, vitrification was insufficient and sufficient ionic conductivity was not obtained. It is considered that this is because the Ge substitution amount y exceeded 0.4. On the other hand, in Examples 6 to 9, sufficient vitrification and sufficient ionic conductivity were obtained. It is considered that this is because the Ge substitution amount y is set to 0.4 or less.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

10 first internal electrode 11 first collector layer 20 second internal electrode 21 second collector layer 30 solid electrolyte layer 40a first external electrode 40b second external electrode 50 cover layer 51 solid electrolyte green sheet 52 for internal electrode Paste 53 Reverse pattern 54 Cover sheet 55 External electrode paste 60 Laminated chip 100, 100a All solid state battery

Claims (6)

a solid electrolyte layer;
a first electrode layer provided on the first main surface of the solid electrolyte layer and containing an electrode active material;
a second electrode layer provided on the second main surface of the solid electrolyte layer and containing an electrode active material;
The solid electrolyte, which is the main component of the solid electrolyte layer, has a structure of (Li _{1+x+(4-A) y} Al _x M _y Ge _2-xy (PO ₄ ) ₃ ), and part of the glass is a crystal. a solid electrolyte made of glass-ceramics,
A is the valence of M, which is a metal;
An all-solid battery, characterized in that 0<A×y≦0.8. The all solid state battery according to claim 1, wherein said M is Zr, Sn, or Ti. The all solid state battery according to claim 1, wherein said M is Co, Mg, or Ca. A green sheet containing a solid electrolyte powder, a first electrode layer paste coating material formed on the first main surface of the green sheet and containing an electrode active material, and an electrode active material formed on the second main surface of the green sheet. a step of preparing a laminate having a paste coating for a second electrode layer comprising
and firing the laminate,
The solid electrolyte powder is a glass solid electrolyte having a structure of (Li _{1+x+(4-A) y} Al _x M _y Ge _2-xy (PO ₄ ) ₃ ),
A is the valence of M, which is a metal;
A method for manufacturing an all-solid-state battery, wherein 0<A×y≦0.8. A raw material powder containing a solid electrolyte powder,
The solid electrolyte powder is a glass solid electrolyte having a structure of (Li _{1+x+(4-A) y} Al _x M _y Ge _2-xy (PO ₄ ) ₃ ),
A is the valence of M, which is a metal;
A raw material powder characterized by 0<A×y≦0.8. Using a raw material containing Li, Al, and metals M, Ge, P, and O, (Li _{1+x+(4-A) y} Al _x M _y Ge _2-xy by a melt quenching method forming a glass solid electrolyte having a structure of (PO ₄ ) ₃ );
The A is the valence of the M,
A method for producing a raw material powder, wherein 0<A×y≦0.8.

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