JP2022135581A - All-solid battery and manufacturing method thereof - Google Patents

Abstract

To increase the humidity resistance of an all-solid battery.SOLUTION: An all-solid battery comprises: a laminate arranged by lamination of first electrode layers, solid electrolyte layers and second electrode layers; a porous layer provided on a surface of the laminate; and an inorganic oxide including silicon impregnated into the porous layer.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to an all-solid-state battery and a manufacturing method thereof.

In recent years, secondary batteries have been used in various fields. A secondary battery using an electrolytic solution has problems such as leakage of the electrolytic solution. Therefore, development of an all-solid-state battery in which a solid electrolyte is provided and other components are also solid is being developed.

When the all-solid-state battery absorbs moisture, the solid electrolyte deteriorates, and the capacity and the like of the all-solid-state battery decrease. In order to prevent this, it has been proposed to provide a moisture-resistant coating layer on the outermost layer of the all-solid-state battery (Patent Documents 1 and 2).

JP-A-2001-43893 JP 2016-167356 A

However, the coating layer may deteriorate due to the load acting on the all-solid-state battery, and may allow moisture to enter, thereby deteriorating the capacity characteristics of the all-solid-state battery.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the moisture resistance of an all-solid-state battery.

An all-solid-state battery according to the present invention includes a laminate in which a plurality of each of a first electrode layer, a solid electrolyte layer, and a second electrode layer are laminated, a porous layer provided on the surface of the laminate, and an inorganic oxide containing silicon impregnated in the porous layer.

In the all-solid-state battery, the outermost layer of the laminate is the solid electrolyte layer, the porous layer is provided on the solid electrolyte layer, and the solid electrolyte layer and the porous layer contain the same element. may contain.

In the all-solid-state battery, the sintering temperature of the porous layer may be higher than the sintering temperature of the solid electrolyte layer.

A method for manufacturing an all-solid-state battery according to the present invention includes steps of forming a laminate in which a plurality of each of a first electrode layer, a solid electrolyte layer, and a second electrode layer are laminated; and a step of impregnating the porous layer with a precursor of an inorganic oxide containing silicon.

In the method for manufacturing an all-solid-state battery, the step of impregnating the porous layer with the solution of the precursor further includes the step of drying the solution to form the inorganic oxide inside the porous layer. You may

ADVANTAGE OF THE INVENTION According to this invention, the moisture resistance of an all-solid-state battery can be improved.

1 is an external view of an all-solid-state battery; FIG. FIG. 2 is a cross-sectional view taken along line II of FIG. 1; 2 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 3 is a flow chart of a method for manufacturing an all-solid-state battery according to the present embodiment; It is a sectional view of an impregnation process. FIG. 3 is a cross-sectional view of an all-solid-state battery according to a comparative example; FIG. 3 is a schematic diagram of an all-solid-state battery according to a comparative example in which cracks occurred in the silica layer in a charge-discharge cycle test; FIG. 3 is a schematic diagram of the all-solid-state battery according to the example during a charge-discharge cycle test;

(embodiment)
FIG. 1 is an external view of an all-solid-state battery 100. FIG. As illustrated in FIG. 1 , the all-solid-state battery 100 includes a rectangular parallelepiped laminated chip 70 and external electrodes 40 a and 40 b provided on two opposing surfaces of the laminated chip 70 .

FIG. 2 is a cross-sectional view taken along line II of FIG. As illustrated in FIG. 2, the laminated chip 70 has a laminated body 60 in which a plurality of solid electrolyte layers 11, first electrode layers 12, and second electrode layers 14 are laminated.

The laminate 60 has a first surface 60a and a second surface 60b parallel to the stacking direction Z of the first electrode layer 12 and the second electrode layer 14 . Among them, the first external electrode 40a is provided on the first surface 60a, and the first electrode layer 12 is connected to the first external electrode 40a. On the other hand, a second external electrode 40b is provided on the second surface 60b, and the second electrode layer 14 is connected to the second external electrode 40b.

Furthermore, the laminate 60 has a third surface 60c and a fourth surface 60d parallel to the first electrode layer 12 and the second electrode layer 14, respectively. The third surface 60c is an upper surface that faces upward when the all-solid-state battery 100 is mounted on the wiring substrate. Further, the fourth surface 60d is a lower surface which is the lower side during mounting. In this example, the outermost layer of laminate 60 is solid electrolyte layer 11, and the surface of solid electrolyte layer 11 defines each of third surface 60c and fourth surface 60d.

Both the first electrode layer 12 and the second electrode layer 14 are conductive layers containing both a positive electrode active material and a negative electrode active material. Although the positive electrode active material is not particularly limited, a material having an olivine crystal structure is used as the positive electrode active material here. Examples of such positive 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 an electrode active material having an olivine type crystal structure, there is, for example, _LiCoPO4 containing Co. A phosphate or the like in which the transition metal Co is replaced in this chemical formula may also be used. Here, the ratio of Li and PO4 can vary depending _on the valence. Co, Mn, Fe, Ni, etc. may be used as the transition metal.

Further, examples of the negative electrode active material include titanium oxide, lithium-titanium composite oxide, lithium-titanium composite phosphate, carbon, and vanadium lithium phosphate.

By using both the positive electrode active material and the negative electrode active material in each of the first electrode layer 12 and the second electrode layer 14 in this way, the similarity of each electrode layer 12 and 14 is enhanced. As a result, each of the first electrode layer 12 and the second electrode layer 14 functions as both a positive electrode and a negative electrode. Also, it can withstand actual use without malfunctioning in short-circuit inspection. Note that the present embodiment is not limited to this, and by forming a positive electrode layer as the first electrode layer 12 and forming a negative electrode layer as the second electrode layer 13, the all-solid-state battery 100 has polarity. may

Furthermore, when producing the first electrode layer 12 and the second electrode layer 14, an oxide-based solid electrolyte material or a conductive aid such as carbon or metal may be added to these electrode layers. Examples of the metal of the conductive aid include Pd, Ni, Cu, and Fe. Furthermore, alloys of these metals may be used as conductive aids.

Also, the layer structures of the first electrode layer 12 and the second electrode layer 14 are not particularly limited. For example, the first electrode layers 12 may be formed on both major surfaces of the first current collector layer 12b made of a conductive material, as indicated within the dotted line circle. Similarly, the second electrode layer 14 may be formed on both main surfaces of the second current collector layer 14b made of a conductive material.

On the other hand, as a material of the solid electrolyte layer 11, for example, there is a phosphate-based solid electrolyte having a NASICON structure. Phosphate-based solid electrolytes having the NASICON structure have high ionic conductivity and are chemically stable in the atmosphere. Although the phosphate-based solid electrolyte is not particularly limited, a phosphate containing lithium is used here. The phosphate is based on, for example, a composite lithium phosphate salt with Ti (LiTi ₂ (PO ₄ ) ₃ ), and a trivalent compound such as Al, Ga, In, Y, or La to increase the Li content. It is a salt in which a transition metal is partially substituted. Such salts include Li _1+x Al _x Ge _2-x (PO ₄ ) ₃ , Li _1+x Al _x Zr _2-x (PO ₄ ) ₃ and Li _1+x Al _x Ti _2-x (PO ₄ ) ₃ . Li--Al--M--PO ₄ system phosphate (M is Ge, Ti, Zr, etc.).

Alternatively, a Li—Al—Ge—PO ₄ -based phosphate to which a transition metal contained in the phosphate in the first electrode layer 12 is added in advance may be used as the material for the solid electrolyte layer 11 . For example, when the first electrode layer 12 contains a phosphate containing either Co or Li, the Li—Al—Ge—PO ₄ -based phosphate to which Co is previously added is used as the solid electrolyte layer 11. may be contained in Thereby, it is possible to suppress the elution of the transition metal from the first electrode layer 12 to the solid electrolyte layer 11 .

Furthermore, a moisture-proof layer 80 is provided on the surface of the outermost solid electrolyte layer 11 of the laminate 60 . The moisture-proof layer 80 is a layer obtained by impregnating a porous layer 80a with an inorganic oxide 80b, and serves to protect the laminate 60 from moisture in the air. Although the porosity of the porous layer 80a is not particularly limited, it is 5% to 60%, more preferably 20% to 40% in this embodiment. The porosity is obtained by using the area A occupied by the porous layer 80a and the total area B occupied by the pores in the cross-sectional image of the porous layer 80a obtained by obtaining a cross-sectional image of the porous layer 80a with a SEM (Scanning Electron Microscope). Defined as (B÷A)×100%. The reason why the upper limit of the porosity is set to 60% is that if the porosity is too high, the strength of the porous layer 80a becomes weak, and cracks and defects occur in the porous layer 80a when impregnated with the inorganic oxide 80b. because there is a risk of Such cracks and defects can be more effectively suppressed by setting the upper limit of the porosity to 40%. On the other hand, the reason why the lower limit of the porosity is set to 5% is that if the porosity is lower than this, it becomes difficult to impregnate the inorganic oxide 80b into the porous layer 80a. In order to easily impregnate the inorganic oxide 80b into the porous layer 80a, it is preferable to set the lower limit of the porosity to 20%.

Furthermore, the ratio of the porous layer 80a and the inorganic oxide 80b in the moisture-proof layer 80 is not particularly limited, either. For example, the volume ratio of the porous layer 80a and the inorganic oxide 80b is 95:5-40:60, more preferably 80:20-60:40. The upper and lower limits of the volume ratio correspond to the upper and lower limits of the porosity of the porous layer 80a. Furthermore, the thickness of the moisture-proof layer 80 is also not particularly limited, and is 0.5 μm to 500 μm, more preferably 50 μm to 200 μm. The reason why the upper limit of the thickness of the moisture-proof layer 80 is set to 500 μm is that if the moisture-proof layer 80 becomes thicker than this, the proportion of the moisture-proof layer 80 in the all-solid-state battery 100 becomes too large, and the capacity of the all-solid-state battery 100 decreases. It is for In order to effectively suppress the capacity reduction of the all-solid-state battery 100 caused by the moisture-proof layer 80, the upper limit of the thickness of the moisture-proof layer 80 is preferably set to 200 μm. On the other hand, the reason why the lower limit of the thickness of the moisture-proof layer 80 is set to 0.5 μm is that the moisture-proof performance of the moisture-proof layer 80 decreases when the moisture-proof layer 80 becomes thinner than this. In order to effectively suppress the deterioration of the moisture-proof performance of the moisture-proof layer 80, it is preferable to set the lower limit of the thickness of the moisture-proof layer 80 to 50 μm.

Although the material of the porous layer 80 a is not particularly limited, it is preferable to form the porous layer 80 a from a material having a sintering temperature higher than that of the solid electrolyte layer 11 . In this specification, the sintering start temperature is called the sintering temperature. This makes it difficult to completely sinter the porous layer 80a, so that a plurality of pores communicating with the outside are formed in the porous layer 80a, and the pores can be easily impregnated with the inorganic oxide 80b. Materials for such a porous layer 80a include, for example, materials represented by the general formula LiM ₂ P ₃ O ₁₂ or the general formula Li _(1+x) Al _x M _(2-x) P ₃ O ₁₂ . Note that M is one of Zr, Ge, and Ti, and 0≦x≦1. Since these materials contain Li and P, which are the same elements as the solid electrolyte layer 11, the adhesion strength between the solid electrolyte layer 11 and the porous layer 80a can be increased.

In order to make the sintering temperature of the porous layer 80a higher than that of the solid electrolyte layer 11, any one of ZrO ₂ , GeO ₂ , TiO ₂ and Al ₂ O ₃ may be added to the porous layer 80a. .

On the other hand, the inorganic oxide 80b is an inorganic oxide containing silicon. Any one of B, Bi, Zn, Ba, Li, P, Sn, Pb, Mg, and Na may be added to the inorganic oxide 80b.

FIG. 3 is a cross-sectional view taken along line II--II in FIG. As illustrated in FIG. 3 , the moisture-proof layer 80 is also provided on the fifth surface 60 e and the sixth surface 60 f of the laminate 60 . The fifth surface 60e and the sixth surface 60f are surfaces perpendicular to each of the first electrode layer 12, the second electrode layer 14, the first surface 60a, and the second surface 60b. This is a side view when the all-solid-state battery 100 is mounted on a substrate.

According to such an all-solid-state battery 100, since the inorganic oxide 80b is impregnated into the porous layer 80a, the periphery of the inorganic oxide 80b is protected by the porous layer 80a. Therefore, the brittle inorganic oxide 80b such as silica is less likely to crack, and moisture in the atmosphere can be prevented from entering the solid electrolyte layer 11 due to cracking. In particular, the inorganic oxide 80b containing silicon, such as silica, has excellent moisture-proof ability, so that the moisture-proof layer 80 can effectively protect the all-solid-state battery 100 .

Next, a method for manufacturing an all-solid-state battery according to this embodiment will be described. FIG. 4 is a flowchart of a method for manufacturing an all-solid-state battery according to this embodiment.

(Ceramic raw material powder preparation process)
First, powder of the phosphate-based solid electrolyte that constitutes the solid electrolyte layer 11 is prepared. For example, the powder of the phosphate-based solid electrolyte that constitutes the solid electrolyte layer 11 can be produced by mixing raw materials and additives and using a solid-phase synthesis method or the like. A desired average particle size can be obtained by dry pulverizing the obtained powder. For example, a planetary ball mill using 5 mmφ ZrO ₂ balls is used to adjust the desired average particle size.

Additives include sintering aids. As a sintering aid, for example, Li—B—O based compounds, Li—Si—O based compounds, Li—C—O based compounds, Li—SO based compounds, and Li—P—O based compounds. Any glass component can be used.

(Green sheet manufacturing process)
Next, the obtained powder is uniformly dispersed in an aqueous solvent or an organic solvent together with a binder, a dispersant, a plasticizer, etc., and wet pulverized to obtain a solid electrolyte slurry having a desired average particle size. 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.

Then, a binder is added to the obtained solid electrolyte slurry to obtain a solid electrolyte paste. A green sheet for the solid electrolyte layer 11 is obtained by applying the solid electrolyte paste. 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.

(Electrode layer paste preparation process)
Next, an electrode layer paste for forming the first electrode layer 12 and the second electrode layer 14 is prepared. For example, a positive electrode active material, a negative electrode active material, and a solid electrolyte material are highly dispersed in a bead mill or the like to prepare a ceramic paste consisting only of ceramic particles. Alternatively, a carbon paste containing carbon particles such as carbon black may be prepared, and the carbon paste may be kneaded with the ceramic paste.

(Porous layer paste preparation step)
Next, a porous layer paste for producing the above-described porous layer 80a is produced. Here, a paste is prepared by dispersing ceramic particles of a material represented by the general formula LiM ₂ P ₃ O ₁₂ or Li _(1+x) Al _x M _(2−x) P ₃ O ₁₂ in a solvent. Note that M is one of Zr, Ge, and Ti, and 0≦x≦1.

(Lamination process)
Next, an electrode layer paste is printed on one main surface of the green sheet. Next, a plurality of printed green sheets are stacked alternately, and cut into a predetermined size with a dicer to obtain a laminate 60 . The uppermost layer and the lowermost layer of the laminate 60 are green sheets.

(Baking process)
Next, the laminate 60 is fired in a firing atmosphere containing oxygen. In order to suppress disappearance of the carbon material contained in the electrode layer paste, the oxygen partial pressure in the firing atmosphere is preferably 2×10 ⁻¹³ atm or less. On the other hand, it is preferable to set the oxygen partial pressure to 5×10 ⁻²² atm or more in order to suppress melting of the phosphate-based solid electrolyte.

Thereafter, a metal paste is applied to each surface 60a, 60b of the laminate 60 and baked to form the first external electrode 40a and the second external electrode 40b. Alternatively, the first external electrode 40a and the second external electrode 40b may be formed by sputtering or plating.

(Coating process)
Next, a porous layer paste is applied to the third to sixth surfaces 60c to 60f of the laminate 60 and fired at a temperature of about 550.degree. C. to 750.degree. C. to obtain the porous layer 80a.

(Impregnation process)
FIG. 5 is a cross-sectional view of the impregnation process. As shown in FIG. 5, the sintered porous layer 80a is impregnated with the solution 81 containing the precursor of the inorganic oxide 80b by utilizing the anchor effect that the solution 81 permeates into the porous layer 80a. A precursor thereof is tetraalkoxysilane, which is dissolved in dibutyl ether or a dibutyl ether-based solvent to obtain a solution containing the precursor. Moreover, in order to facilitate impregnation of the solution 81 into the porous layer 80a, it is preferable to perform this step in a reduced pressure atmosphere.

(Heating process)
Next, the porous layer 80a is heated to a temperature of about 100° C. to 150° C. to dry the solvent, and the tetraalkoxysilane is hydrolyzed to obtain orthosilicic acid. Furthermore, by maintaining the porous layer 80a in a heated state, the orthosilicic acid is dehydrated and polymerized to form silica as the inorganic oxide 80b inside the porous layer 80a. With the above, the basic structure of the all-solid-state battery 100 is completed.

All-solid-state batteries according to Examples and Comparative Examples were produced as follows.

First, Co ₃ O ₄ , Li ₂ CO ₃ , ammonium dihydrogen phosphate, Al ₂ O ₃ and GeO ₂ were mixed to obtain Li _1.3 Al _0.3 Ge 1.3 Al 0.3 Ge 1.3 containing a predetermined amount of Co as a solid electrolyte material powder _{. 7} (PO4) ₃ was prepared by solid _- phase synthesis. The powder obtained was dry-milled with ZrO ₂ balls. Furthermore, a solid electrolyte slurry was prepared by wet pulverization using ion-exchanged water or ethanol as a dispersion medium. A binder was added to the obtained slurry to obtain a solid electrolyte paste, and a green sheet was produced. LiCoPO ₄ and Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ containing a predetermined amount of Co were synthesized by solid phase synthesis in the same manner as above.

In the examples, a positive electrode active material, a negative electrode active material, and a solid electrolyte material were highly dispersed in a wet bead mill or the like to prepare a ceramic paste consisting only of ceramic particles. Next, the ceramic paste and the conductive aid were thoroughly mixed to prepare an electrode layer paste for forming the first electrode layer 12 and the second electrode layer 14 .

LiCoPO ₄ was used as the positive electrode active material. Li _1+x Al _x Ti _2-x (PO ₄ ) ₃ was used as a negative electrode active material.

An electrode layer paste was printed on the green sheet by screen printing. 11 printed green sheets were laminated so that the electrodes were pulled out from the left and right. After that, the green sheets were pressed together by hot pressing, and each green sheet was cut by a dicer to obtain a laminate 60 having a predetermined size.

The laminate 60 was heat-treated at 300° C. or higher and 500° C. or lower for degreasing, and heat-treated at 900° C. or lower for sintering. After that, a first external electrode 40a and a second external electrode 40b were formed on each surface 60a, 60b of the laminate 60. As shown in FIG.

Next, the porous layer paste was applied to the third to sixth surfaces 60c to 60f of the laminate 60, and sintered at a temperature of about 550.degree. C. to 750.degree. C. to obtain the porous layer 80a. Further, the porous layer 80a was impregnated with a solution of tetraalkoxysilane dissolved in dibutyl ether, and heated to 200° C. to 500° C. to form silica as the inorganic oxide 80b inside the porous layer 80a. .

(Comparative example)
FIG. 6 is a cross-sectional view of an all-solid-state battery 200 according to a comparative example. In the comparative example, the laminate 60 was directly coated with a solution of tetraalkoxysilane dissolved in dibutyl ether without forming the porous layer 80 a on the surface of the laminate 60 . Then, the silica layer 90 was formed on the surface of the laminate 60 by heating the solution to 200.degree. C. to 500.degree. The silica layer 90 is a layer expected as a moisture-proof layer for protecting the laminate 60 from moisture contained in the atmosphere.

Next, the characteristics of all-solid-state batteries were examined for Examples and Comparative Examples. The results are shown in Tables 1 and 2.

この調査では、充放電サイクル試験、湿度フロート試験、温度サイクル試験、実装機械強度試験、及び振動試験を行った。充放電サイクル試験では、充放電を１００回繰り繰り返した。充放電を繰り返すと各電極層１２、１４がリチウムイオンの放出と吸収を繰り返すことで膨張と収縮を繰り返す。これにより積層体６０が全体として膨張や収縮を繰り返し、防湿層８０（実施例）とシリカ層９０（比較例）の各々にストレスが加わる。この調査では、そのストレスによって防湿層８０（実施例）とシリカ層９０（比較例）の各々に目視で割れが生じたかを判定した。なお、実施例と比較例の各々のサンプル数は５個とした。また、表１では、目視で割れが生じなかったサンプルの個数を記している。

In this investigation, a charge/discharge cycle test, a humidity float test, a temperature cycle test, a mounting mechanical strength test, and a vibration test were conducted. In the charge/discharge cycle test, charge/discharge was repeated 100 times. When charging and discharging are repeated, the electrode layers 12 and 14 repeatedly expand and contract due to repeated release and absorption of lithium ions. As a result, the laminate 60 as a whole repeatedly expands and contracts, and stress is applied to each of the moisture-proof layer 80 (Example) and the silica layer 90 (Comparative Example). In this investigation, it was determined whether the stress caused visual cracks in each of the moisture-proof layer 80 (Example) and the silica layer 90 (Comparative Example). The number of samples for each of the examples and the comparative examples was five. Table 1 also shows the number of samples that did not visually crack.

Furthermore, when the moisture-proof layer 80 (example) and the silica layer 90 (comparative example) are cracked, the solid electrolyte layer 11 absorbs moisture and the capacity of the battery decreases. Therefore, in the charge-discharge cycle test, the number of samples maintaining 80% or more of the initial capacity was also examined in each of the examples and the comparative examples.

In the humidity float test, the all-solid-state batteries 100 and 200 were left for 1000 hours in an atmosphere with a temperature of 85° C. and a relative humidity of 85%. After that, as in the charge-discharge cycle test, the number of samples in which no cracks occurred and the number of samples in which 80% or more of the initial capacity was maintained were examined.

In the temperature cycle test, the temperature of each all-solid-state battery 100, 200 was repeatedly changed to temperatures of −20° C., 20° C., and 75° C., and the stress associated with the temperature change was applied to the moisture-proof layer 80 (example) and the silica layer 90 ( Comparative Example). The time for maintaining each of -20°C, 20°C and 75°C was 4 hours, and the number of cycles was 5 cycles. After that, the number of samples in which cracks did not occur and the number of samples in which 80% or more of the initial capacity was maintained were examined.

In the mounting mechanical strength test, each of the all-solid-state batteries 100 and 200 was mounted on the wiring board with solder, and the wiring board was warped in this state to apply stress to each of the moisture-proof layer 80 (Example) and the silica layer 90 (Comparative Example). was added. After that, the number of samples in which cracks did not occur was examined.

In the vibration test, stress was applied to each of the moisture-proof layer 80 (Example) and the silica layer 90 (Comparative Example) by vibrating each of the all-solid-state batteries 100 and 200 . The magnitude of acceleration accompanying vibration was set to 20 G, and the vibration frequency was set to 100 Hz to 3000 Hz. Also, the test was conducted in accordance with JIS C 5101 and IEC60384. After that, the number of samples in which cracks did not occur was examined.

As shown in Tables 1 and 2, in the comparative example, there were samples in which the silica layer 90 cracked in the charge/discharge cycle test, humidity float test, and temperature cycle test. Additionally, the humidity float test showed a capacity below 80% of the initial capacity for all five samples. In addition, in the charge/discharge cycle test and the temperature cycle test, the capacity of four of the five samples according to the comparative example was below 80% of the initial capacity.

FIG. 7 is a schematic diagram of an all-solid-state battery 200 according to a comparative example in which cracks occurred in the silica layer 90 in the charge-discharge cycle test. As illustrated in FIG. 7, the first electrode layer 12 expands due to charging and discharging, and cracks 90a are generated in the silica layer 90 accordingly. Also, a gap 90b is formed at the junction between the first external electrode 40a and the silica layer 90. As shown in FIG. In the comparative example, it is considered that the moisture in the air penetrated into the solid electrolyte layer 11 through the cracks 90a and the gaps 90b, thereby reducing the capacity.

On the other hand, in the examples, no cracks were observed in any of the five samples in all tests, and the initial capacity was maintained at 80% or more.

FIG. 8 is a schematic diagram of the all-solid-state battery 100 according to the example during a charge-discharge cycle test. As illustrated in FIG. 8, although the first electrode layer 12 expands due to charging and discharging, the inorganic oxide 80b is protected by the surrounding porous layer 80a, so that the inorganic oxide 80b is not cracked. not occurred.

From this result, it became clear that forming the moisture-proof layer 80 with the porous layer 80a and the inorganic oxide 80b as in the example is useful for improving the moisture resistance of the all-solid-state battery 100.

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.

11: solid electrolyte layer 12: first electrode layer 12b: first collector layer 14: second electrode layer 14b: second collector layer 40a: first external electrode 40b: second external Electrode 60 : Laminated bodies 60a to 60f : First to sixth surfaces 70 : Laminated chip 80 : Moisture-proof layer 80a : Porous layer 80b : Inorganic oxide 81 : Solution 90 : Silica layer 90b : Gap 100, 200 : All solid battery

Claims (5)

a laminate in which a plurality of each of the first electrode layer, the solid electrolyte layer, and the second electrode layer are laminated;
a porous layer provided on the surface of the laminate;
an inorganic oxide containing silicon impregnated in the porous layer;
An all-solid-state battery characterized by comprising: The outermost layer of the laminate is the solid electrolyte layer,
The porous layer is provided on the solid electrolyte layer,
2. The all-solid-state battery according to claim 1, wherein the solid electrolyte layer and the porous layer contain the same element. 3. The all-solid battery according to claim 1, wherein a sintering temperature of said porous layer is higher than a sintering temperature of said solid electrolyte layer. forming a laminate in which a plurality of each of the first electrode layer, the solid electrolyte layer, and the second electrode layer are laminated;
forming a porous layer on the surface of the laminate;
impregnating the porous layer with an inorganic oxide precursor containing silicon;
A method for manufacturing an all-solid-state battery, comprising: The step of impregnating the porous layer with the precursor solution includes:
5. The method for manufacturing an all-solid-state battery according to claim 4, further comprising the step of forming the inorganic oxide inside the porous layer by drying the solution.

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