JP2018041917A - Capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor which enables the reduction in dielectric loss in e.g. a practical frequency band.SOLUTION: A capacitor 1 comprises: a central solid electrolyte layer 3 having a pair of principal faces 5, 11, and including a solid electrolyte (e.g. LLZ) having lithium ion conductivity as a primary component; and a pair of internal electrode layers 7, 13 disposed on the pair of principal faces 5, 11. Particularly the central solid electrolyte layer 3 includes metal particles made of nickel. Therefore, it brings about the effect of reducing a dielectric loss of the capacitor 1 in a practical frequency band of e.g. 40 Hz to 110 MHz. In other words, the capacitor is arranged so that nickel metal particles are included in the central solid electrolyte layer 3, and thus it has the effect where the dielectric loss becomes lower than that when the central solid electrolyte layer is formed by only a solid electrolyte.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a capacitor (capacitor) that stores and discharges electric charge, and more particularly to a capacitor using a solid electrolyte having lithium ion conductivity.

Conventionally, for example, a solid capacitor in which a pair of electrodes is provided on the surface of a solid electrolyte or a dielectric is known (see Patent Documents 1 to 5 below).
For example, Patent Document 1 discloses a basic structure and characteristics of an electric double layer capacitor using a solid electrolyte between electrodes.

  Patent Document 2 discloses that a solid ion capacitor having an improved capacitance can be obtained by thinning a solid electrolyte as compared with a conventional electric double layer capacitor using an electrolytic solution.

Patent Document 3 discloses that a capacitor having excellent frequency characteristics can be obtained by reducing the thickness of a dielectric layer containing a Li ion conductive compound.
Patent Documents 4 and 5 disclose techniques for increasing the capacity by including metal particles in a dielectric between electrodes. In Patent Documents 4 and 5, there is a description about the metal content and the particle size, but there is no description about the ratio of the metal particle size to the thickness between the electrodes. In general, it is known that even when metal particles are included in a dielectric, the loss of the capacitor (that is, reduction of the dielectric loss) does not occur.

JP 2008-130844 A International Publication No. 2013/111804 JP 2013-225534 A Japanese Patent Laid-Open No. 2015-43389 JP 2006-287203 A

However, the above-described prior art has the following problems, and improvements are desired.
Specifically, when a solid electrolyte is disposed between electrodes of a solid capacitor, generally, the relaxation frequency of the grain boundary (that is, the frequency at which the dielectric loss increases) is, for example, a practical frequency band such as 40 Hz to 110 MHz. Therefore, there is a problem that the dielectric loss of the solid capacitor increases.

For this reason, when a solid capacitor is used in the above-described practical frequency band, there is a possibility that restrictions such as insufficient performance may be obtained.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a capacitor capable of reducing dielectric loss in a practical frequency band, for example.

  (1) 1st aspect of this invention has a pair of main surface, the solid electrolyte layer which has as a main component the solid electrolyte which has lithium ion conductivity, and a pair of electrode layer arrange | positioned at a pair of main surface, The solid electrolyte layer includes metal particles.

  Thus, in the first aspect, since the solid electrolyte layer contains metal particles, the dielectric loss of the capacitor is reduced in a practical frequency band such as 40 Hz to 110 MHz, as is apparent from an experimental example described later. There is an effect that it can be reduced.

In other words, the inclusion of metal particles in the solid electrolyte layer has an effect that the dielectric loss is lower than that of the solid electrolyte alone.
In addition, since the low loss capacitor is actually obtained in the practical frequency band by the research of the present inventors, it is considered that the inclusion of metal particles in the solid electrolyte layer contributes to the reduction of the loss. However, the detailed principle is not clear.

  (2) In 2nd aspect of this invention, content of the metal particle in a solid electrolyte layer is 1 volume% or more and 30 volume% or less, and the metal with respect to thickness T1 of the solid electrolyte layer between a pair of electrode layers The ratio (D1 / T1) of the average particle diameter D1 of the particles is 0.5 or less.

  In the second aspect, since the content of metal particles and the ratio (D1 / T1) are in the above-described range, as is clear from an experimental example described later, for example, in a practical frequency band, the dielectric loss of the capacitor is reduced. There is an effect that it can be greatly reduced.

(3) In 3rd aspect of this invention, content of the metal particle in a solid electrolyte layer is 10 volume% or more and 30 volume% or less.
In the third aspect, since the content of the metal particles is in the above-described range, there is an effect that the dielectric loss of the capacitor can be greatly reduced, for example, in a practical frequency band, as is clear from the experimental examples described later.

(4) In the fourth aspect of the present invention, the ratio (D1 / T1) is 0.05 or more and 0.5 or less.
In the fourth aspect, since the ratio (D1 / T1) is in the above-described range, as is apparent from an experimental example to be described later, for example, in the practical frequency band, there is an effect that the dielectric loss of the capacitor can be greatly reduced. is there.

(5) In the fifth aspect of the present invention, the solid electrolyte is Li ₇ La ₃ Zr ₂ O ₁₂ .
The fifth aspect shows a preferable example of the solid electrolyte.
Specifically, Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) has an advantage that it can be fired at the same time as, for example, a Ni electrode and has high ionic conductivity.

<Hereinafter, each configuration of the present invention will be described>
The “solid electrolyte layer” is a layer having characteristics as a solid electrolyte, that is, a characteristic (ion conductivity) in which ions (here, lithium ions) can be moved by an electric field applied from the outside.

“The main component” indicates that the corresponding component is the most abundant component (for example, 50% by volume or more).
-"A pair of main surface" has shown one surface and the other surface formed in the edge part of the thickness direction of a solid electrolyte layer.

  “Metal particles” are made of a single metal or an alloy metal, are not in contact with the electrode layer, and are electrically independent. The shape of the metal particles is not limited at all, and various shapes can be adopted.

It is a perspective view which shows the capacitor of 1st Embodiment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view (AA cross-sectional view) showing a fractured surface of a capacitor according to a first embodiment, which is broken in the stacking direction (Z direction) of each layer. (A) is BB sectional drawing of FIG. 2, (b) is CC sectional drawing of FIG. It is explanatory drawing explaining the manufacturing process of the capacitor of 1st Embodiment about one capacitor. It is sectional drawing which fractures | ruptures the capacitor of 2nd Embodiment in the lamination direction (Z direction) of each layer, and shows the torn surface.

[1. First Embodiment]
[1-1. Capacitor configuration]
First, the configuration of the capacitor according to the first embodiment will be described.

  In the following description, explanations will be made using each of the upper, lower, left and right directions in the figure. The direction in which the capacitor is oriented is arbitrary. For example, “up, down, left, right” indicating directions in the following description is the same as the “up, down, left, right” directions in FIG.

As shown in FIG. 1, the capacitor 1 of the first embodiment is a cuboid monolithic ceramic chip capacitor.
Specifically, as schematically shown in FIG. 2, the capacitor 1 has a single solid electrolyte layer (that is, a central solid electrolyte layer) in the central portion in the stacking direction (vertical direction in FIG. 2: Z direction). 3 is arranged.

  Further, on one main surface (first main surface 5) of the central solid electrolyte layer 3, that is, on the surface of one side in the stacking direction (upper side in FIG. 1 internal electrode layer) 7 is disposed.

  Further, another solid electrolyte layer (that is, the first internal electrode layer 7) is formed on the upper surface of the first internal electrode layer 7 and the exposed surface (that is, the portion not covered with the first internal electrode layer 7) of the central solid electrolyte layer 3. An outer solid electrolyte layer) 9 is disposed.

  On the other hand, on the surface of the other main surface (second main surface 11) of the central solid electrolyte layer 3, that is, the other side in the stacking direction (lower side in FIG. 2; hereinafter referred to as the lower side), Another internal electrode layer (that is, second internal electrode layer) 13 similar to the electrode layer 7 is disposed.

  Further, the lower outer surface of the second internal electrode layer 13 and the exposed lower surface of the central solid electrolyte layer 3 (that is, the portion not covered with the second internal electrode layer 13) are provided with the first outer solid electrolyte layer. 9, another solid electrolyte layer (ie, second outer solid electrolyte layer) 15 is disposed.

These layers 3, 7, 9, 13, and 15 are laminated to form a rectangular parallelepiped base 17.
In addition, external electrodes 19 are formed over the entire surface so as to cover both sides of the capacitor 1 in the left-right direction (left-right direction: X direction in FIG. 2), that is, both sides of the base body 17 in the left-right direction. That is, the first external electrode 19a is formed on the left side of FIG. 2, and the second external electrode 19b is formed on the right side of FIG.

Hereinafter, each configuration will be described in more detail.
The central solid electrolyte layer 3 contains, for example, Li ₇ La ₃ Zr ₂ O ₁₂ (hereinafter sometimes referred to as LLZ) as a main component, and metal particles such as nickel (Ni) are dispersed therein.

Further, the thickness T1 of the central solid electrolyte layer 3 is, for example, 20 μm in the range of 1 to 30 μm, for example.
The content of the metal particles in the central solid electrolyte layer 3 is in the range (for example, 10% by volume) of 1% by volume to 30% by volume (preferably 10% by volume to 30% by volume).

The average particle diameter D1 of the metal particles is, for example, 4 μm in the range of 0.1 to 10 μm, for example.
Furthermore, the ratio (D1 / T1) of the average particle diameter D1 of the metal particles to the thickness T1 of the central solid electrolyte layer 3 is, for example, 0.2 in the range of 0.5 or less (preferably 0.05 to 0.5). is there.

As shown in FIG. 3A, the first internal electrode layer 7 is a rectangular conductive layer made of nickel, for example.
The first internal electrode layer 7 is connected to the first external electrode 19a, extends to the second external electrode 19b side, and covers most of the upper surface of the central solid electrolyte layer 3 (for example, 70% of the surface area). Yes. However, the first internal electrode layer 7 is not connected to the second external electrode 19 b, and there is a gap 21 between the first internal electrode layer 7 and the outer periphery of the base body 17. The solid electrolyte layer 3 and the first outer solid electrolyte layer 9 are joined.

Similarly, as shown in FIG. 3B, the second internal electrode layer 13 is a rectangular conductive layer made of nickel, for example.
The second internal electrode layer 13 is connected to the second external electrode 19b, extends to the first external electrode 19a side, and covers most of the lower surface of the central solid electrolyte layer 13 (for example, 70% of the surface area). Yes. However, the second internal electrode layer 13 is not connected to the first external electrode 19 a, and there is a gap 23 between the second internal electrode layer 13 and the outer periphery of the base body 17. The solid electrolyte layer 3 and the second outer solid electrolyte layer 15 are joined.

Returning to FIG. 2, the first outer solid electrolyte layer 9 is formed so as to cover the entire exposed portions of the upper surfaces of the first internal electrode layer 7 and the central solid electrolyte layer 3.
The first outer solid electrolyte layer 9 is made of the same solid electrolyte material as the central solid electrolyte layer 3, that is, LLZ, but does not contain metal particles. In addition, the thickness of the 1st outer side solid electrolyte layer 9 is 140 micrometers, for example.

Similarly, the second outer solid electrolyte layer 15 is formed so as to cover the entire exposed portions of the lower surfaces of the second internal electrode layer 13 and the central solid electrolyte layer 3.
The second outer solid electrolyte layer 15 is made of the same solid electrolyte material as that of the central solid electrolyte layer 3, that is, LLZ, but does not contain metal particles. The thickness of the second outer solid electrolyte layer 15 is, for example, 140 μm.
[1-2. Capacitor manufacturing method]
Next, a method for manufacturing the capacitor 1 according to the first embodiment will be described.

  Here, a case where a flat base material is used in order to manufacture a plurality of capacitors 1 collectively will be described as an example, but the present invention is not limited to this. For example, the capacitor 1 may be manufactured independently.

<Calcined powder production process>
First, in order to produce Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) which is a solid electrolyte body, a predetermined amount of lithium carbonate, lanthanum hydroxide, and zirconium oxide are used as starting materials so as to have a molar ratio of LLZ. Weighed and mixed to make a mixed material.

  The mixed material was mixed with ethyl alcohol using a nylon pot and zirconia cobblestone. After the mixture was dried, it was calcined by holding at 1100 ° C. for 10 hours in an air atmosphere using an alumina crucible to produce a LLZ calcined powder.

<Crushed powder preparation process>
Next, the calcined powder of LLZ was pulverized for 36 hours using a nylon pot and zirconia spherulite together with methyl ethyl ketone and dried to prepare a pulverized powder of LLZ.

<Slurry production process>
Next, pulverized powder of LLZ, a binder (butyral resin), and a plasticizer (dioctyl phthalate) were mixed with a methyl ethyl ketone / toluene mixed solvent to prepare a slurry of LLZ.

<Sheet preparation process>
Next, the LLZ slurry was applied to a carrier film made of polyethylene terephthalate (PET) treated with silicon (Si) on one side by a doctor blade method to produce a sheet (ie, initial sheet) having a thickness of about 30 μm. .

<Internal electrode printing process>
Next, the initial sheet was punched into a predetermined size (for example, a rectangular shape having a predetermined dimension), and a sheet to be laminated later (hereinafter, this sheet is simply referred to as a sheet) was obtained.

  Next, as shown in FIG. 4A, a portion corresponding to one capacitor 1 is formed on one surface of a certain sheet 31 by screen printing using a Ni electrode material, for example, the first internal electrode layer 7 and the like. A first electrode pattern 33 was formed.

  Similarly, as shown in FIG. 4B, a second electrode pattern 37 to be, for example, the second internal electrode layer 13 is formed on one surface of the other sheet 35 by screen printing using a Ni electrode material. did.

  In order to manufacture a large number of capacitors 1 at once, a large number of electrode patterns 33 and 37 were formed on the sheets 31 and 35, respectively. Further, as is well known, the material for the Ni electrode is a paste obtained by adding a binder and a solvent to Ni powder.

<Solid electrolyte layer forming step>
Next, as shown in FIG. 4C, the central LLZ layer 39 that becomes the central solid electrolyte layer 3 is formed so as to cover the surface of the sheet 31 on which one electrode pattern (for example, the first electrode pattern 33) is printed. The material was screen-printed so that the thickness of the central solid electrolyte layer 3 after firing was 20 μm, and then dried.

  Here, the material of the central LLZ layer 39 is a paste obtained by adding a known binder (for example, ethyl cellulose) and a solvent (for example, terpineol) to the LLZ pulverized powder and Ni powder.

  Specifically, in order to obtain Examples 1 to 10 used in the evaluation described later, as the material of the central solid electrolyte layer 3 of Examples 1 to 10, the material of the central LLZ layer 39 in which the particle size and addition amount of Ni powder are changed. Was used. In addition, the material of the central solid electrolyte layer 3 of the comparative example is the material of the central LLZ layer 39 produced without adding Ni powder.

<Laminated body production process>
Next, as shown in FIG. 4D, for example, only one sheet 31 on which the material of the central LLZ layer 39 is screen-printed on the first electrode pattern 33 and, for example, the second electrode pattern 37 are formed. One sheet 35 was laminated by laminating the sheet surfaces. That is, the printed central LLZ layer 39 and, for example, the second electrode pattern 37 are bonded and laminated so as to face each other.

  Thereafter, although not shown, after peeling the PET carrier film on the exposed side surface of one of the bonded sheets 31, a predetermined number of sheets (for example, six sheets) were sequentially laminated. Similarly, after peeling off the PET carrier film on the exposed surface of the other bonded sheet 35, a predetermined number of sheets (for example, six sheets) were sequentially laminated.

In this way, a LLZ laminate was produced so that the structure (laminated structure) shown in FIG. 2 was obtained after firing.
And the produced laminated body (base material) was hold | maintained at 196 MPa for 1000 second, heating at 80 degreeC with WIP (Warm Isostatic Press), and performed the high pressure press.

Thereafter, the laminated body subjected to high-pressure pressing was subjected to break processing along the product shape using a CO ₂ laser processing machine, and was broken along the break grooves into individual pieces.
Next, Ni electrodes that become the first and second external electrodes 19a and 19b on the side surfaces where the first and second internal electrode layers 7 and 13 are exposed with respect to the separated members (elements), respectively. The material was applied.

<Baking process>
Next, the element before baking which apply | coated the material of Ni electrode to each side surface was heated at 300 degreeC by air | atmosphere atmosphere, and the binder removal process was carried out. Thereafter, it was fired in a hydrogen-nitrogen mixed atmosphere at a maximum temperature of 1200 ° C. for 2 hours to produce a flat plate-shaped capacitor 1 having the dimensions described above.
[1-3. Capacitor evaluation]
Next, evaluation (experimental example) for confirming the performance of the capacitor will be described.

  First, about each sample (Examples 1-10, comparative example) obtained by the manufacturing method mentioned above, AC impedance measurement etc. are carried out at measurement voltage 0.1V and measurement frequency 40Hz-110MHz using Agilent 4294A. went.

  In addition, SEM observation with a scanning electron microscope (SEM) was performed. Specifically, cross section polisher (CP) processing or mirror polishing processing equivalent thereto was performed on a cross section of the sintered body (that is, a cross section in which the capacitor was broken along the thickness direction). Then, element analysis mapping or backscattered electron imaging was performed on the polished surface in an enlarged field of view of 500 times that of SEM, and an image capable of distinguishing the boundary between the solid electrolyte and Ni was obtained.

  Thereafter, image analysis of the image was performed, the range in which the count number of nickel particles (Ni particles) was 50 or more was specified, the particle diameter (particle diameter) was measured, and the average value was taken as the Ni particle diameter. Further, the Ni content [volume%] per volume in the central solid electrolyte layer was calculated from the amount of Ni powder added to the LLZ material constituting the central solid electrolyte layer.

Further, the ratio (Ni particle diameter / central solid electrolyte layer thickness = D1 / T1) between the Ni particle diameter (D1) and the thickness (T1) of the central solid electrolyte layer was determined.
Furthermore, as an evaluation of the reduction in loss, in order to investigate the degree of improvement of tan δ of each sample of Examples 1 to 10 with respect to tan δ of the comparative example (when the solid electrolyte layer does not contain Ni), the reduction rate of tan δ was obtained. It was. The rate of decrease of tan δ was calculated as {1- (tan δ of each sample) / (tan δ of comparative example)} × 100 at a measurement frequency of 100 kHz.

Here, tan δ represents dielectric loss, and is an absolute value of (real part) / (imaginary part) of impedance at a specific frequency.
Further, the apparent relative dielectric constant (εr) (simply referred to as relative dielectric constant in Table 1) is determined by the area S of the overlapping portion of the pair of internal electrode layers facing the capacitance C at the measurement frequency of 100 kHz and the central solid electrolyte layer. with thickness d, it was calculated in εr = Cd / Sε _0. Note that ε ₀ is the dielectric constant of vacuum.

  These results are shown in Table 1 below. In Table 1, “loss reduction effect”, Δ is “tan δ decrease rate is less than 5%”, ○ is “tan δ decrease rate is less than 50%”, and ◎ is “tan δ decrease rate is 50%”. % Or more ".

この表１から明らかなように、実施例１は、低損失化の効果が５％未満であり、低損失化の効果が僅かに見られた。実施例２〜３と実施例７〜９より、Ｎｉ含有量が同じでも、Ｎｉ粒子径／固体電解質層の厚みを小さくすると、ｔａｎδの低下率が大きくなる傾向にあることが分かる。また、実施例３〜７と実施例１０より、Ｎｉ粒子径／固体電解質層の厚みが同じでも、Ｎｉ含有量が多くなるとｔａｎδの低下率が大きくなる傾向にあることが分かる。これは、Ｎｉ粒子径／固体電解質層の厚み（Ｄ１／Ｔ１）が小さく、Ｎｉ含有量が多いほど、低損失化の効果が大きくなることを示唆している。

As can be seen from Table 1, in Example 1, the effect of reducing the loss was less than 5%, and the effect of reducing the loss was slightly seen. From Examples 2-3 and Examples 7-9, it can be seen that even when the Ni content is the same, the decrease rate of tan δ tends to increase when the Ni particle diameter / solid electrolyte layer thickness is decreased. Further, from Examples 3 to 7 and Example 10, it can be seen that even when the Ni particle diameter / the thickness of the solid electrolyte layer are the same, the decrease rate of tan δ tends to increase as the Ni content increases. This suggests that the smaller the Ni particle diameter / the thickness of the solid electrolyte layer (D1 / T1) and the greater the Ni content, the greater the effect of reducing the loss.

  From these results, even when the Ni content is less than 1% by volume, the effect of reducing the loss is observed, the Ni particle diameter / the thickness of the solid electrolyte layer (D1 / T1) is 0.5 or less, and the Ni content is 1 It can be seen that if the volume% or more, the reduction rate of tan δ is 5% or more and the effect of reducing the loss appears.

In particular, when the Ni content is 10% by volume or more, the reduction rate of tan δ is 50% or more, and it can be seen that a greater effect can be obtained.
Further, the apparent relative dielectric constant of the capacitor was not less than the relative dielectric constant (3000) of barium titanate (BT), which is a general MLCC material satisfying the B characteristics.
[1-4. effect]
Next, the effect of the capacitor 1 of the first embodiment will be described.

  The capacitor 1 of the first embodiment has a pair of main surfaces 5 and 11, a central solid electrolyte layer 3 mainly composed of a solid electrolyte (here, LLZ) having lithium ion conductivity, and a pair of main surfaces. 5 and 11 and a pair of internal electrode layers 7 and 13. In particular, the central solid electrolyte layer 3 includes metal particles made of nickel.

Therefore, as is clear from the experimental example described above, there is an effect that the dielectric loss of the capacitor 1 can be reduced in a practical frequency band such as 40 Hz to 110 MHz.
In other words, the inclusion of metal particles made of nickel in the central solid electrolyte layer 3 has the effect that the dielectric loss is lower than that formed only by the solid electrolyte. Further, the relative dielectric constant is equal to or higher than that of barium titanate, which is a general MLCC material.

  In the first embodiment, the content of the metal particles in the central solid electrolyte layer 3 is 1 vol% or more (preferably 10 vol% or more) and 30 vol% or less, and the pair of internal electrode layers 7, 13. The ratio (D1 / T1) of the average particle diameter D1 of the metal particles to the thickness T1 of the central solid electrolyte layer 3 in between can be 0.5 or less (preferably 0.05 or more).

As a result, as is clear from the experimental example described above, there is an effect that the dielectric loss of the capacitor 1 can be greatly reduced, for example, in a practical frequency band.
By using LLZ as the solid electrolyte, reduction firing can be performed with the internal electrode layers 7 and 13 made of nickel, so that there is an advantage that ion conductivity can be increased.
[1-5. Correspondence with Claims]
The central solid electrolyte layer 3 and the internal electrode layers 7 and 13 of the first embodiment correspond to examples of the solid electrolyte layer and the electrode layer of the present invention, respectively.
[2. Second Embodiment]
Next, the second embodiment will be described, but the description of the same contents as the first embodiment will be omitted or simplified.

  As shown in FIG. 5, the capacitor 51 of the second embodiment has a plurality of central solid electrolyte layers 53 made of a solid electrolyte body containing Ni particles (similar to the first embodiment) on the center side in the thickness direction. I have. Furthermore, internal electrode layers 55 (similar to the first embodiment) are formed on both sides of each central solid electrolyte layer 53 in the thickness direction. The internal electrode layer 55 sandwiched between the pair of central solid electrolyte layers 53 is shared.

  The other configuration is the same as that of the first embodiment. A first outer solid electrode layer 59 made of a solid electrolyte body containing no Ni particles is formed on one side of the capacitor 51 in the thickness direction, and the other is formed on the other side. A second outer solid electrode layer 59 made of a solid electrolyte body that does not contain Ni particles is formed.

An external electrode 61 (similar to the first embodiment) is formed on the side surface of the capacitor 51 (left and right side surfaces in FIG. 5).
The second embodiment has the same effects as the first embodiment.

The number and arrangement of the plurality of central solid electrolyte layers are not limited to the configuration of the second embodiment.
[3. Other Embodiments]
It goes without saying that the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the present invention.

(1) For example, Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) can be used as the solid electrolyte, but other lithium ion conductors can be used.
For _{example, Li 1 + x Al x Ge} 2-x (PO 4) 3, Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP), Li x Zr y Nb z (PO 4) 3 (LZNP ), Li _1.2 Zr _1.9 Ca _0.1 (PO ₄ ) ₃ (LZCP), Li _7-x La ₃ Zr _2-x Nb _x O ₁₂ (LLZN), Li _7-x La ₃ Zr _{2− x Ta x O 12 (LLZT)} , Li 3x La 2 / 3x Ti 1 / 3x O 3 (LLT), Li 6 BaLa 2 Ta 2 O 12 (LBLT), Li 3 BO 3, Li 3 PO 4 _{-x N x (LiPON), LiS} -P 2 S 5 (LPS), it can be adopted lithium ion conductor, such as _{Li 10 GeP 2 S 12 (LGPS} ).

  (2) The solid electrolyte layer is preferably composed only of the above-described solid electrolyte having lithium ion conductivity. However, the solid electrolyte layer may contain a material other than the solid electrolyte in a range of less than 50% by volume. Can be adopted.

  In addition, as materials other than the solid electrolyte contained in the solid electrolyte layer, for example, a material having electrical insulation (that is, electrical insulation related to electron conductivity and ion conductivity) such as barium titanate (BT) can be employed. Examples of the material having electrical insulation include metal oxides such as strontium titanate, alumina, zirconia, and silica, and resins such as polyethylene, polypropylene, ABS, acrylic, epoxy, and polyimide.

Furthermore, oxides of elements constituting the solid electrolyte can be employed as materials other than the solid electrolyte contained in the solid electrolyte body. Examples of the oxide material of the element constituting the solid electrolyte include AlPO ₄ , TiO ₂ , LaTiO _{3 and the} like.

  (3) As a method of forming the solid electrolyte layer, a green sheet is prepared using the slurry containing the solid electrolyte material described above, and the green sheet is fired under a predetermined condition to thereby obtain a solid electrolyte layer (accordingly, Various known methods such as a method of forming a laminate can be employed.

  (4) Examples of the metal constituting the metal particles include simple metals and alloys. For example, in addition to Ni, for example, Au, Pt, Pd, Ag, and Cu can be cited. Further, for example, an alloy of Au, Pt, Pd, Ag, Ni, Cu can be mentioned.

  (5) As the material of the internal electrode layer, various known conductive materials such as Au, Pt, Pd, Ag, Ni, Cu, etc. can be adopted. As a method of forming the internal electrode layer, various known methods such as a screen printing method using a slurry or paste containing the conductive material can be employed. For example, a thin film method, a coating method, a thermal spraying method, a sputtering method, a plating method, or the like can be adopted. For the external electrode, the same material and the same formation method as the internal electrode layer can be adopted.

  (6) The configurations of the above embodiments can be combined as appropriate.

DESCRIPTION OF SYMBOLS 1, 51 ... Capacitor 3, 53 ... Central solid electrolyte layer 5 ... 1st main surface 7 ... 1st internal electrode layer 11 ... 2nd main surface 13 ... 2nd internal electrode layer 19, 61 ... External electrode layer

Claims (5)

A capacitor having a pair of principal surfaces, a solid electrolyte layer mainly composed of a solid electrolyte having lithium ion conductivity, and a pair of electrode layers disposed on the pair of principal surfaces,
A capacitor, wherein the solid electrolyte layer includes metal particles. The content of the metal particles in the solid electrolyte layer is 1% by volume or more and 30% by volume or less,
The capacitor according to claim 1, wherein a ratio (D1 / T1) of an average particle diameter D1 of the metal particles to a thickness T1 of the solid electrolyte layer between the pair of electrode layers is 0.5 or less.   3. The capacitor according to claim 1, wherein a content of the metal particles in the solid electrolyte layer is 10% by volume or more and 30% by volume or less.   The capacitor according to claim 1, wherein the ratio (D1 / T1) is 0.05 or more and 0.5 or less. The capacitor according to claim 1, wherein the solid electrolyte is Li ₇ La ₃ Zr ₂ O ₁₂ .

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