JP2011249706A - Capacitor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor with a larger capacity than that of conventional one.SOLUTION: A capacitor 100 comprises an anode layer 10, a cathode layer 20, and a solid electrolyte layer 30 arranged between these electrode layers 10 and 20. At least one of the electrode layers 10 (20) of this capacitor 100 comprises an Al porous body 11 and an electrode body 12 (13) which is supported by this Al porous body 11 to polarize the electrolyte. The oxygen amount of the surface of the Al porous body 11 is 3.1 mass% or less, which means that an oxide film of high resistance is hardly formed on the surface of the Al porous body 11. Therefore, this Al porous body 11 allows enlarging the power collection area of the electrode layer 10 (20) so as to improve the capacity of the capacitor 100.

Description

  The present invention relates to a capacitor used as a device for storing electrical energy and a method for manufacturing the same.

  Examples of devices that store electrical energy include secondary batteries and capacitors. Both of them are provided with an electrolyte layer and two electrode layers sandwiching the electrolyte layer, but their storage systems are different. The secondary battery stores electric energy by a chemical reaction in the electrode layer, whereas the capacitor stores electric energy by physical adsorption of electrolyte ions on the electrode layer.

  In such a capacitor, with the recent development of electrical equipment, there is a demand for higher output and higher capacity. As means for meeting this demand, it has been studied to increase the current collection area by making the current collector in the electrode layer porous, and to arrange an electrode body such as carbon that polarizes the electrolyte in the pores. In particular, production of a porous current collector (Al porous body) with Al, which is a material suitable as a current collector, has been studied.

  As a method for producing an Al porous body, for example, Patent Document 1 discloses that an Al porous body containing a large number of bubbles is produced by adding a foaming agent to molten Al and stirring. In Patent Document 2, an Al porous body is manufactured by forming an Al film on a skeleton of a foamed resin having a three-dimensional network structure, and then burning the foamed resin by heat treatment at about 550 to 750 ° C. Is disclosed.

JP 2002-371327 A JP-A-8-170126

  However, when a capacitor was produced using the Al porous body obtained by the production methods described in Patent Documents 1 and 2, there were the following problems.

  Since any Al porous body of Patent Documents 1 and 2 has a step of heating Al during the production process, an oxide film is easily formed on the surface of the Al porous body during cooling. Since this oxide film has a high resistance, when an Al porous body having an oxide film is used for a capacitor, the capacity of the capacitor is lowered rather than a capacitor not using the Al porous body.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a capacitor having a larger capacity than before.

  Another object of the present invention is to provide a capacitor manufacturing method capable of stably manufacturing a capacitor having a larger capacity than the conventional one.

(1) The capacitor of the present invention includes an anode layer, a cathode layer, and a solid electrolyte layer disposed between these electrode layers. At least one electrode layer of the capacitor includes an Al porous body and an electrode body that is held in the Al porous body and polarizes an electrolyte, and an oxygen amount on the surface of the Al porous body is 3.1 mass. % Or less.

  The amount of oxygen on the surface of the Al porous body being 3.1% by mass or less is equivalent to the fact that a high resistance oxide film is hardly formed on the surface of the Al porous body. Therefore, this Al porous body can increase the effective current collection area of the electrode layer, thereby improving the capacity of the capacitor. In addition, the manufacturing method of Al porous body whose surface oxygen amount is 3.1 mass% or less is demonstrated in detail in embodiment mentioned later.

(2) As one form of the capacitor of the present invention, the electrode body provided in the electrode layer is preferably formed in a film shape on the surface of the Al porous body (including the surface in the pores).

  By forming the electrode body on the surface of the Al porous body, the contact area between the Al porous body as a current collector and the electrode body can be increased. As a result, the capacitance of the capacitor can be greatly improved.

(3) As one form of the capacitor of the present invention, the electrode body provided in the electrode layer is preferably filled in pores formed in an Al porous body.

  By filling the pores in the Al porous body with the electrode body, the contact area between the Al porous body that is a current collector and the electrode body can be increased. As a result, the capacitance of the capacitor can be greatly improved.

(4) As one form of the capacitor of the present invention, the Al porous body provided in the capacitor is preferably pure Al.

  By making the Al porous body pure Al, it is possible to obtain an Al porous body having higher conductivity than the alloy-based Al porous body. As a result, the capacitance of the capacitor can be greatly improved.

(5) A method for producing a capacitor of the present invention is a method for producing a capacitor comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between these electrode layers. Prepare.
A step of preparing an Al porous body that is an Al porous body that serves as a current collector of the electrode layer and that has an oxygen content of 3.1% by mass or less on the surface thereof.
A step of forming an electrode body for polarizing an electrolyte in the form of a film on the surface of the Al porous body to be one of the anode layer and the cathode layer. Here, the electrode body is formed by a vapor phase method.

  According to the method for manufacturing a capacitor of the present invention, a capacitor of the present invention including an electrode body formed in a film shape on the surface of a current collector (Al porous body) can be manufactured.

(6) A manufacturing method of a capacitor of the present invention is a manufacturing method of a capacitor for manufacturing a capacitor including an anode layer, a cathode layer, and a solid electrolyte layer disposed between these electrode layers. Prepare.
A step of preparing an Al porous body that is an Al porous body that serves as a current collector of the electrode body and whose surface has an oxygen content of 3.1% by mass or less.
A step of filling the pores formed in the Al porous body with a composite material containing conductive particles serving as an electrode body for polarizing an electrolyte;
A step of pressurizing the Al porous body filled with the composite material to be one of the anode layer and the cathode layer.

  According to the method for manufacturing a capacitor of the present invention, the capacitor of the present invention including the electrode body filled in the pores of the current collector can be manufactured.

  The capacitor according to the present invention includes an Al porous body having a large current collection area and an Al porous body on which almost no high-resistance oxide film is formed, and therefore has a larger capacity than a conventional capacitor. Therefore, the capacitor of the present invention can be suitably used as a backup power source for electrical equipment.

(A) is a schematic configuration diagram of a capacitor according to the embodiment, (B) is a schematic configuration diagram illustrating a configuration in which an electrode body constituting an electrode layer of the capacitor is formed in a film shape on the surface of an Al porous body, (C) is a schematic configuration diagram illustrating a configuration in which an electrode body is filled in pores of an Al porous body. It is a schematic diagram explaining the manufacturing process of Al porous body. (A) shows the partially expanded cross section of the resin body which has a communicating hole. (B) shows a state in which an Al layer is formed on the surface of the resin constituting the resin body. (C) shows an Al porous body in which the resin body is thermally decomposed to leave the Al layer and disappear the resin. It is a schematic diagram explaining the thermal decomposition process of the resin body in molten salt.

  Hereinafter, an example of the capacitor of the present invention and a manufacturing method thereof will be described with reference to the drawings.

<Overall configuration>
A capacitor 100 shown in FIG. 1 has a configuration in which a solid electrolyte layer (SE layer 30) is sandwiched between an anode layer 10 and a cathode layer 20. The anode layer 10 includes an anode layer body 10A and a substrate 10B that supports the anode layer body 10A, and the cathode layer 20 includes a cathode layer body 20A and a substrate 20B that supports the cathode layer body 20A. The substrates 10B and 20B can be omitted. Hereinafter, each configuration of the capacitor 100 will be described in detail.

≪Anode layer≫
The anode layer body 10A of the anode layer 10 is fixed on an insulating substrate 10B such as a polyethylene sheet via a resin adhesive. The anode layer body 10A includes an Al porous body 11 in which pores formed therein communicate with each other and almost no independent pores are present, and an electrode body that is held in the Al porous body 11 and polarizes an electrolyte. Prepare. Here, there are roughly two types of configurations of the electrode body, and each configuration will be described later with reference to FIGS. 1B and 1C. First, the Al porous body 11 will be described in detail with reference to FIGS.

[Al porous body]
The most characteristic feature of the Al porous body 11 is that the oxygen content on the surface thereof is 3.1 mass% or less. The oxygen amount here is a value obtained by quantitative analysis of the surface of the Al porous body 11 by EDX (energy dispersive X-ray analysis) under the condition of an acceleration voltage of 15 kV, and the oxygen amount of 3.1 mass% or less is EDX. Is below the detection limit.

First, the Al porous body 11 serving as a current collector can be manufactured by, for example, a manufacturing method including the following steps.
Manufacturing method: After forming the Al layer on the resin surface of the resin body having the communication holes, the Al body is immersed in the molten salt while applying a lower potential to the Al layer than the standard electrode potential of Al. The resin body is pyrolyzed by heating to a temperature below the melting point.
The method for producing the Al porous body will be described with reference to FIG.

(Resin body with communication holes)
FIG. 2A shows a partially enlarged cross section of a resin body 1f having communication holes. The resin body 1f has communication holes formed with the resin 1 as a skeleton. As the resin body 1f having the communication holes, a nonwoven fabric made of resin fibers can be used in addition to the foamed resin. The resin constituting the resin body 1f may be any resin that can be thermally decomposed at a heating temperature lower than the melting point of Al. Examples thereof include polyurethane, polypropylene, and polyethylene. In particular, urethane foam is preferably used for the resin body 1f because it has a high porosity, a uniform pore diameter, and excellent pore connectivity and thermal decomposability. The pore diameter of the resin body 1f is preferably in the range of about 5 μm to 500 μm, and the porosity is preferably in the range of about 80% to 98%. The pore diameter and porosity of the Al porous body 11 finally obtained are determined by the resin body 1f. It is influenced by pore diameter and porosity. Therefore, the pore diameter and the porosity of the resin body 1f are determined according to the pore diameter and the porosity of the Al porous body 11 to be produced.

(Formation of Al layer on resin surface)
FIG. 2B shows a state where the Al layer 2 is formed on the surface of the resin 1 of the resin body having communication holes (Al layer coating resin body 3). Examples of the method for forming the Al layer 2 include (i) a vapor deposition method (PVD) represented by a vacuum deposition method, a sputtering method, a laser ablation method, and the like, (ii) a plating method, and (iii) a paste coating method. Can be mentioned.

(I) Vapor phase method In the vacuum deposition method, for example, an Al layer is obtained by irradiating an electron beam to a raw material Al to melt and evaporate Al, and adhere Al to the resin surface of the resin body 1f having communication holes. 2 can be formed. In the sputtering method, for example, the Al layer 2 can be formed by irradiating an Al target with plasma to vaporize Al and depositing Al on the resin surface of the resin body 1 f having communication holes. In the laser ablation method, for example, the Al layer 2 can be formed by melting and evaporating Al by laser irradiation and adhering Al to the resin surface of the resin body 1f having the communication holes.

(Ii) Plating method Plating Al in an aqueous solution is practically impossible. Therefore, by the molten salt electroplating method in which Al is plated in a molten salt, the resin surface of the resin body 1f having communication holes is formed. The Al layer 2 can be formed. In this case, it is preferable to plate Al in a molten salt after conducting the conductive treatment on the resin surface in advance.

As the molten salt used for the molten salt electroplating, for example, a salt such as lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), or Al chloride (AlCl ₃ ) can be used. Moreover, it is good also as a eutectic molten salt by mixing the salt of 2 or more components. The eutectic molten salt is advantageous in that the melting temperature can be lowered. This molten salt needs to contain Al ions.

The molten salt electroplating, for _example, AlCl 3 -XCl: 2 component of salt (X alkali metal) _or,, AlCl 3 -XCl (X: alkali metal)-MCL _x (M is Cr, a transition metal element such as Mn A multi-component salt of an element selected from the above is melted to form a plating solution, and the resin body 1f is immersed in this to perform electrolytic plating, thereby applying Al plating to the resin surface. . In addition, as a pretreatment for electrolytic plating, it is preferable to conduct a conductive treatment on the resin surface in advance. As a conductive treatment, a conductive metal such as nickel is plated on the resin surface by electroless plating, a conductive metal such as Al is coated on the resin surface by a vacuum deposition method or a sputtering method, or a conductive material such as carbon. For example, a conductive paint containing particles may be applied.

(Iii) Paste coating method In the paste coating method, for example, an Al paste in which Al powder, a binder (binder), and an organic solvent are mixed is used. And after apply | coating Al paste to the resin surface, while heating, a binder and an organic solvent are lose | disappeared, and Al paste is sintered. This sintering may be performed once or divided into a plurality of times. For example, after the Al paste is applied, the organic solvent is eliminated by heating at a low temperature, and then the Al paste is sintered at the same time as the thermal decomposition of the resin body 1f by heating in a molten salt. Is possible. Further, this sintering is preferably performed in a non-oxidizing atmosphere.

(Thermal decomposition of resin in molten salt)
FIG. 2C shows a state (Al porous body 11) in which the resin 1 is thermally decomposed from the Al layer coating resin body 3 shown in FIG. The thermal decomposition of the resin body 1f (resin 1) is performed by heating to a temperature not higher than the melting point of Al while applying a base potential to the Al layer 2 while being immersed in the molten salt. For example, as shown in FIG. 3, a resin body (that is, an Al layer coating resin body 3) and a counter electrode (positive electrode) 5 in which an Al layer is formed on the resin surface are immersed in a molten salt 6 so that it is lower than the standard electrode potential of Al. An appropriate potential is applied to the Al layer. By applying a base potential to the Al layer in the molten salt, oxidation of the Al layer can be reliably prevented. Here, the potential applied to the Al layer is lower than the standard electrode potential of Al and more noble than the reduction potential of the cation of the molten salt. The counter electrode may be any material that is insoluble in the molten salt. For example, platinum, titanium, or the like can be used.

  And while maintaining this state, only the resin in the Al layer coating resin body 3 is lost by heating the molten salt 6 to a melting point of Al (660 ° C.) or lower and higher than the thermal decomposition temperature of the resin body. Accordingly, the resin can be thermally decomposed without oxidizing the Al layer, and as a result, the Al porous body 11 having a surface oxygen amount of 3.1% by mass or less can be obtained (FIG. 2 (C )reference). Moreover, what is necessary is just to set suitably the heating temperature when thermally decomposing a resin body according to the kind of resin which comprises a resin body, for example, it is preferable to set it as 500 to 600 degreeC.

The molten salt used in the thermal decomposition step of the resin body may be the same as the molten salt used in the molten salt electroplating described above. For example, lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl) It is preferable to contain at least one selected from the group consisting of Al chloride (AlCl ₃ ). As the molten salt, a salt of an alkali metal or alkaline earth metal halide can be used so that the potential of the Al layer is low. Moreover, in order to make the melting temperature of molten salt into the temperature below melting | fusing point of Al, it is good also as a eutectic molten salt by mixing 2 or more types of salts. In particular, since Al is easily oxidized and difficult to reduce, it is effective to use a eutectic molten salt in the thermal decomposition step of the resin body.

  In addition, the Al porous body 11 produced by the method for producing an Al porous body has a hollow fiber shape due to the characteristics of the production method. In this respect, the structure is different from the Al foam disclosed in Patent Document 1. And the Al porous body 11 has a communicating hole and does not have a closed pore, or even if it has it, it is very small. In addition, the Al porous body 11 is formed of pure Al (made of Al and inevitable impurities) and also made of an Al alloy containing added elements (the added elements and the balance are made of Al and inevitable impurities). May be. When formed of an Al alloy, the mechanical properties of the Al porous body can be improved as compared with pure Al.

[Electrode body]
The electrode body includes (i) a structure formed on the surface of the Al porous body 11 as shown in FIG. 1B, and (ii) an Al porous body 11 as shown in FIG. There are two configurations: a configuration in which the pores are filled. Hereinafter, both configurations will be described separately.

(I) Electrode body formed in a film shape A thin film electrode body 12 shown in FIG. 1 (B) is formed on the surface of the Al porous body 11 described above. It has a structure in which fine particles are dispersed. The conductive fine particles are for adsorbing and holding electrolyte ions. C is preferably used as a constituent element of the conductive fine particles. As the solid electrolyte, for _example, it can be suitably used sulfides such as _{Li 2 S-P 2 S 5} . An oxide such as P ₂ O ₅ may be added to this Li ₂ S—P ₂ S ₅ to improve the chemical stability of the sulfide solid electrolyte. In that case, it is preferable that the content of O in the sulfide solid electrolyte does not exceed 10 atomic%. If the O content exceeds 10 atomic%, the diffusion rate of electrolyte (Li) ions may decrease, and the response speed of electrolyte polarization to voltage application may decrease.

  The most important parameter in the electrode body 12 is the average particle diameter of the conductive fine particles. This is because the factor that determines the capacity of the capacitor 100 is the total surface area of the conductive fine particles that adsorb electrolyte ions. Therefore, in the capacitor 100 of the present invention, the average particle diameter of the conductive fine particles in the anode layer 10 is set in the range of 1 to 50 nm. If the conductive fine particles have an average particle diameter in this range, the total surface area of the conductive fine particles in the anode layer 10 (area capable of adsorbing electrolyte ions: adsorption area) can be sufficiently secured.

An important parameter of the electrode body 12 is the number density of conductive fine particles in the electrode body 12. The specific number density of the conductive fine particles is preferably 5 × 10 ¹⁵ to 1 × 10 ²¹ particles / cm ³ . In that case, the adsorption area per unit volume of the electrode body 12 is theoretically about 6 × 10 ^{5 to} 3 × 10 ⁷ cm ² / cm ³ , and the volume ratio of the conductive fine particles in the electrode body 12 is about 40 to 60 volumes. %. If it is the anode layer 10 provided with such an electrode body 12, the capacitor | condenser 100 provided with the capacity | capacitance which can fully respond to various uses can be manufactured.

  In addition, as a parameter of the electrode body 12, the thickness of the electrode body 12 can be mentioned. The thickness of the electrode body 12 may be appropriately selected according to the capacity required for the capacitor 100. In this case, it goes without saying that the particle size and number density of the conductive fine particles are taken into consideration. For example, the thickness of the electrode body 12 is preferably 1 to 500 μm.

  The electrode body 12 described above can be formed by a vapor phase method in an Ar atmosphere using the Al porous body 11 as a substrate. For the vapor phase method, a physical vapor phase method such as a laser ablation method or a vacuum deposition method can be used.

  In order to produce the electrode body 12 by the vapor phase method, first, a conductive material that physically adsorbs electrolyte ions and a solid electrolyte are prepared. When the conductive material and the solid electrolyte are prepared, the Al porous body 11 is disposed in the chamber, and these film-forming materials are simultaneously evaporated in a single evaporation source (crucible) in the chamber, or separately in different evaporation sources. The electrode body 12 is formed on the surface of the Al porous body 11 (including the inside of the pores). The electrode body 12 formed by the series of operations has a structure in which the conductive material is dispersed in the sulfide solid electrolyte matrix in the form of fine particles.

  By the way, although the conductive material evaporated from the evaporation source becomes fine particles and travels toward the substrate, the fine particles are likely to aggregate while reaching from the evaporation source to the substrate, and become large particles. Therefore, in order to set the average particle size of the conductive fine particles in the electrode body 12 to 1 to 50 nm, it is necessary to inhibit the particles of the conductive material from aggregating in the film forming atmosphere. In the present embodiment, since Ar is present in the film formation atmosphere, there is less opportunity for the conductive material particles to contact each other, and aggregation of the fine particles is inhibited.

There is an appropriate range for the atmospheric pressure of Ar that inhibits aggregation of fine particles. Specifically, the atmospheric pressure of Ar is preferably 10 ^{−2 to 1} Pa. If the atmospheric pressure is within this range, it is possible to effectively suppress aggregation of the conductive material particles.

  In addition, the distance from the evaporation source (crucible) of the conductive material to the substrate 10B is also an element that affects the degree of aggregation of the particles of the conductive material. Therefore, the distance is preferably between 10 and 70 mm. In that case, the electrode body 12 can be formed while effectively suppressing aggregation of particles of the conductive material.

(Ii) Filled Electrode Body A filled electrode body 13 shown in FIG. 1C includes conductive fine particles 13A and electrolyte fine particles 13B filled in the pores of the Al porous body 11 described above. As the material of the conductive fine particles 13A and the electrolyte fine particles 13B, the same material as the electrode body 12 formed in a film shape may be used.

  An important parameter in the electrode body 13 is the particle size and mixing ratio of the fine particles 13A and 13B. Specifically, the particle diameter of the conductive fine particles 13A is preferably 1 to 100 nm, and the particle diameter of the electrolyte fine particles 13B is preferably 10 to 100 nm. The mixing ratio is preferably mass%, and the conductive fine particles 13A: electrolyte fine particles 13B = 35: 65 to 60:40.

  The electrode body 13 described above can be manufactured as follows, for example. First, fine particles 13A and 13B having a desired particle diameter are produced by mechanical milling or the like, and these fine particles 13A and 13B are mixed by a mixing means such as a ball mill. Next, after filling the pores of the Al porous body 11 with the mixed material, the Al porous body 11 is compressed, whereby the electrode body 13 composed of the fine particles 13A and 13B closely packed in the pores can be formed. The compression pressure is preferably in the range of 100 to 1000 MPa.

≪SE layer≫
The SE layer 30 formed on the anode layer 10 is a layer containing a solid electrolyte, and is a layer that insulates the anode layer 10 and the cathode layer 20. The characteristics required for the solid electrolyte are low electron conductivity and excellent electrolyte ion conductivity. For example, sulfides such as Li ₂ S—P ₂ S ₅ can be used. The solid electrolyte constituting the SE layer 30 is preferably made of the same material as the solid electrolyte of the anode layer 10. In that case, since the migration resistance of the electrolyte ions becomes uniform in the entire capacitor 100, performance such as responsiveness of the capacitor 100 can be improved.

  The thickness of the SE layer 3 is preferably about 1 to 100 μm. The thinner one can increase the capacity, but if it is too thin, it tends to cause a short circuit between the electrodes. In the case of the capacitor 100, the capacitance of the capacitor 100 changes depending on the thickness of the SE layer 30 corresponding to the electrode interlayer distance. Therefore, the thickness of the SE layer 30 may be determined according to the use of the capacitor 100.

  The SE layer 30 described above can be formed by a physical vapor phase method such as a laser ablation method or a vacuum deposition method. Alternatively, the SE layer 30 may be formed by pressing and solidifying a solid electrolyte powder. Here, when the SE layer 30 is formed by the vapor phase method, when the solid electrolyte constituting the SE layer 30 is the same as the solid electrolyte contained in the anode layer 10, following the formation of the anode layer 10, The SE layer 30 is preferably formed. In that case, when the thickness of the anode layer 10 reaches a desired value, the evaporation of the conductive material may be stopped and the evaporation of the solid electrolyte may be continued.

≪Cathode layer≫
The cathode layer 20 in the present embodiment has the same configuration as the anode layer 10 and can be formed under the same film formation conditions as the anode layer 10. In this case, since a common sulfide solid electrolyte is used from the cathode layer 20 to the anode layer 10 via the SE layer 30, performance such as responsiveness of the capacitor 100 can be improved.

  The cathode layer 20 may be made of a material different from that of the anode layer 10 and a different film forming condition. In addition, the cathode layer 20 may be a Faraday electrode (an electrode that stores electric charge by a chemical reaction) having a completely different configuration from a polarizable electrode such as the anode layer 10. In that case, the capacitor 100 is a hybrid capacitor including a polarizable electrode and a Faraday electrode.

<Summary>
The capacitor 100 manufactured as described above includes the Al porous body 11 having a large current collecting area and the Al porous body 11 on which almost no high-resistance oxide layer is formed. Also has a large capacity. As a result, the capacitor 100 can be suitably used for various applications such as a backup power source for electrical equipment.

  The Al porous body 11 shown in the above embodiment and a conventional Al porous body for comparison were produced, and the capacitor 100 shown in FIG. 1 was produced using each porous body. And the capacity | capacitance (F) of these capacitors 100 was actually measured.

(Preparation of Al porous body of embodiment)
As shown in FIG. 2A, a polyurethane foam (urethane foam) having a porosity of about 97%, a pore diameter of about 15 μm, and a thickness of about 0.1 mm was prepared as the resin body 1f.

Next, pure Al was melted and evaporated by a vacuum deposition method to form an Al layer 2 on the resin surface of the resin body 1f (see FIG. 2B). The conditions for vacuum deposition were a degree of vacuum of 1.0 × 10 ⁻⁵ Pa, a temperature of the resin body 1f to be coated at room temperature, and a distance between the evaporation source and the resin body 1f of 300 mm. After the Al layer 2 was formed on the resin surface of the resin body 1f, the resin body 1f (Al layer coating resin body 3) having the Al layer 2 formed on the resin surface was observed by SEM. The thickness of the Al layer 2 was It was 3 μm.

  Next, as shown in FIG. 3, the Al layer coating resin body 3 is immersed in a eutectic molten salt 6 of LiCl—KCl at 500 ° C., and in this state, the Al layer is brought to the standard electrode layer potential of Al. On the other hand, a negative voltage was applied to the Al layer for 30 minutes so that the base potential would be -1V. At this time, it was confirmed that bubbles were generated in the molten salt 6. This is presumably due to thermal decomposition of polyurethane.

  Next, the skeleton (Al porous body) made of Al after the resin body obtained by the above process is thermally decomposed is cooled to room temperature in the atmosphere, then washed with water, and the dissolved salt adhering to the surface is removed. Removed. The Al porous body 11 was completed by the above (refer FIG.2 (C)).

  The produced Al porous body 11 had a porosity of 95%, a pore diameter of 15 μm, and a thickness of 0.1 mm. Moreover, when this Al porous body 11 was observed by SEM, the hole was connected and the closed pore was not confirmed. Further, when the surface of the Al porous body 11 was quantitatively analyzed by EDX at an acceleration voltage of 15 kV, no oxygen peak was observed. That is, oxygen was not detected. Therefore, the amount of oxygen on the surface of the Al porous body 11 was less than the detection limit by EDX, that is, 3.1% by mass or less. The apparatus used in this analysis is “EDAX Phoenix model: HIT22 136-2.5” manufactured by EDAX.

(Preparation of a porous Al body for comparison)
For comparison, an Al porous body having a different manufacturing method from the Al porous body of the embodiment was also produced. In this comparative Al porous body, an Al layer coating resin body is produced by the same manufacturing method as the Al porous body of the embodiment until an Al layer is formed on the resin surface of the resin body, and the subsequent resin body is thermally decomposed. It was produced by changing the process. Specifically, by heat-treating the Al layer coating resin body at 550 ° C. in the atmosphere, the resin body was thermally decomposed to disappear the resin. This comparative Al porous body had a porosity of 95%, a pore diameter of 15 μm, and a thickness of 0.1 mm.

  When the surface of the comparative Al porous body was quantitatively analyzed by EDX at an acceleration voltage of 15 kV, an oxygen peak was observed, and the oxygen amount on the surface was more than 3.1 mass%. This is presumably because the surface of the porous Al body was oxidized when the resin body was heat-treated.

(Capacitor production)
Next, the capacitor 100 of FIG. 1A having the thin-film electrode body 12 shown in FIG. 1B using either the Al porous body 11 of the manufactured embodiment or the comparative Al porous body, or FIG. 1A having the filling-type electrode body 13 shown in FIG. 1C was manufactured.

  The capacitor 100 shown in FIG. 1A including the electrode body 12 shown in FIG. 1B was manufactured as follows.

First, an Al porous body as an embodiment or a comparison was prepared, and an anode layer 10 was produced by forming a film-like electrode body 12 by a laser ablation method in the pores of the Al porous body. The conditions of the laser ablation method are as follows.
Electrolyte raw material: Li ₂ S—P ₂ S ₅ pressure molded body (diameter 20 mm, thickness 5 mm)
Conductive fine particle raw material ... C sintered compact (diameter 20mm, thickness 5mm)
Li ₂ S-P ₂ S ₅ pressure-formed body and distance from C sintered body to Al foil (substrate) ... 50 mm
Deposition atmosphere ... Ar
Deposition pressure ... 10 ^-1 Pa
In forming the electrode layer, the electrolyte material and the conductive fine particle material were alternately irradiated with laser. For example, the electrolyte material 10 seconds and the conductive fine particle material 10 seconds are alternately repeated to form a predetermined thickness.

When the cross section of the produced electrode layer was observed with an electron microscope, C particles were almost uniformly dispersed in the matrix of Li ₂ S—P ₂ S ₅ . The average particle size of the C particles was about 10 nm. The average particle diameter was obtained by averaging the equivalent circle diameter calculated from the area of each C particle for 100 or more C particles in the microscope field.

Next, only the electrolyte raw material was irradiated with laser on the electrode layer to form the SE layer 30, and finally, the electrolyte raw material and the conductive fine particle raw material were alternately irradiated with laser to form the cathode layer 20.
Electrode layers 10, 20 ... φ10mm, thickness 5μm
SE layer 30 ... φ10mm, thickness 1μm

  An Al electrode was formed to a thickness of 0.1 μm on the cathode layer 20 by a vacuum deposition method to obtain a current collector. The Al porous body as a base material was enclosed in a heat-resistant coin-type case as a current collector for the anode layer 10 to complete a capacitor element.

  On the other hand, the capacitor 100 of FIG. 1A provided with the electrode body 13 shown in FIG. 1C was manufactured as follows. The anode layer 10 and the cathode layer 20 have the same configuration.

  First, an Al porous body as an embodiment or a comparison is prepared, and a mixture of a solid electrolyte powder having an average particle diameter of 0.5 μm and acetylene black having an average particle diameter of 0.05 μm is placed in the pores of the Al porous body. Filled. The mixing ratio of these solid electrolyte powder and acetylene black was 50:50 by mass ratio. A planetary ball mill was used to mix the two.

  Next, an Al porous body filled with pores of the mixed material was pressurized at 500 MPa to produce an electrode layer 10 (20) composed of the Al porous body and an electrode body made of carbon / solid electrolyte. The thickness of the electrode layer 10 (20) at this time was 0.05 mm, and the compression ratio (thickness after pressing / thickness before pressing) was 50%.

Further, the produced electrode layer 10, the solid electrolyte powder, and the remaining electrode layer 20 are arranged in this order in a mold having a diameter of 10 mm, and pressure-molded at a pressure of 500 MPa, and the anode layer 10 -SE layer 30 -cathode layer. A capacitor element consisting of 20 was completed. Here, the solid electrolyte powder for forming the SE layer 30 was the same Li ₂ S—P ₂ S ₅ as used in the electrode layers 10 and 20. The dimensions of each layer of the completed capacitor are as follows.
Electrode layers 10, 20 ... φ10mm, thickness 0.05mm
SE layer 30 ... φ10mm, thickness 0.05mm

  Finally, the capacitor element produced was enclosed in a heat-resistant coin-type case to complete the capacitor 100.

  For the four types of capacitors 100 manufactured as described above, the capacitance of each capacitor 100 was measured from the voltage and current values when the capacitor 100 was charged. The results are shown in Table 1.

  As shown in Table 1, both the capacitor 100 including the electrode body 12 of the type shown in FIG. 1B and the capacitor 100 including the electrode body 13 of the type shown in FIG. The capacitance of the capacitor 100 was improved when the oxygen content on the surface of the Al porous body 11 was 3.1 mass% or less. This is because, when the amount of oxygen on the surface of the Al porous body 11 is small, that is, when an oxide film is not formed on the surface of the Al porous body 11, the electricity between the Al porous body 11 and the electrode body 12 (13). This is presumably because the resistance is reduced.

  The embodiment of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

  The capacitor of the present invention can be suitably used for backup power sources such as an IC memory, a lighting road sign, and a lighting roadway.

DESCRIPTION OF SYMBOLS 1 Resin 1f Resin body 2 Al layer 3 Al layer coating resin body 5 Counter electrode (positive electrode)
6 Molten salt 100 Capacitor 10 Anode layer (electrode layer)
10A Anode layer body 10B Substrate 11 Al porous body 12, 13 Electrode body 13A Conductive fine particles 13B Electrolytic fine particles 20 Cathode layer (electrode layer)
20A Cathode layer body 20B Substrate 30 Solid electrolyte layer (SE layer)

Claims (6)

A capacitor comprising an anode layer, a cathode layer, and a solid electrolyte layer disposed between these electrode layers,
At least one of the electrode layers includes an Al porous body that functions as a current collector, and an electrode body that is held in the Al porous body and polarizes an electrolyte,
The capacitor according to claim 1, wherein the amount of oxygen on the surface of the Al porous body is 3.1% by mass or less.   The capacitor according to claim 1, wherein the electrode body is formed in a film shape on the surface of an Al porous body.   The capacitor according to claim 1, wherein the electrode body is filled in pores formed in an Al porous body.   The said Al porous body is pure Al, The capacitor as described in any one of Claims 1-3 characterized by the above-mentioned. A capacitor manufacturing method for manufacturing a capacitor comprising an anode layer, a cathode layer, and a solid electrolyte layer disposed between these electrode layers,
A step of preparing an Al porous body that is an Al porous body that serves as a current collector of the electrode layer, the oxygen amount of the surface of which is 3.1% by mass or less;
On the surface of the Al porous body, forming an electrode body that polarizes an electrolyte into a film shape to be one of the anode layer and the cathode layer;
With
The method of manufacturing a capacitor, wherein the electrode body is formed by a vapor phase method. A capacitor manufacturing method for manufacturing a capacitor comprising an anode layer, a cathode layer, and a solid electrolyte layer disposed between these electrode layers,
A step of preparing an Al porous body that is an Al porous body to be a current collector of the electrode body, and an oxygen amount of the surface of which is 3.1 mass% or less;
Filling the composite material containing conductive particles to be electrode bodies for polarizing the electrolyte into the pores formed in the Al porous body;
Pressurizing the Al porous body filled with the composite material to form either the anode layer or the cathode layer; and
A method for producing a capacitor, comprising:

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