WO2019230676A1 - 電解コンデンサ及びその製造方法 - Google Patents

電解コンデンサ及びその製造方法 Download PDF

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WO2019230676A1
WO2019230676A1 PCT/JP2019/020989 JP2019020989W WO2019230676A1 WO 2019230676 A1 WO2019230676 A1 WO 2019230676A1 JP 2019020989 W JP2019020989 W JP 2019020989W WO 2019230676 A1 WO2019230676 A1 WO 2019230676A1
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cathode
conductive
polymer layer
conductive polymer
layer
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PCT/JP2019/020989
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English (en)
French (fr)
Japanese (ja)
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良弥 小関
和宏 長原
健治 町田
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日本ケミコン株式会社
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Priority to JP2020522193A priority Critical patent/JP7343847B2/ja
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/02—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof using combined reduction-oxidation reactions, e.g. redox arrangement or solion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/48—Conductive polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/022—Electrolytes; Absorbents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/022—Electrolytes; Absorbents
    • H01G9/025—Solid electrolytes
    • H01G9/028—Organic semiconducting electrolytes, e.g. TCNQ
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/04—Electrodes or formation of dielectric layers thereon
    • H01G9/042—Electrodes or formation of dielectric layers thereon characterised by the material

Definitions

  • the present invention relates to an electrolytic capacitor including a cathode having a conductive polymer layer that exhibits a redox capacity.
  • An electrolytic capacitor having an ion conductive electrolyte generally includes an anode in which an oxide film as a dielectric layer is provided on the surface of a valve metal foil such as aluminum, tantalum, or niobium, and a valve.
  • a current collecting cathode (apparent cathode) composed of a metal foil or the like and a separator holding an ion conductive electrolyte as a true cathode disposed between the anode and the cathode are accommodated in a sealed case.
  • a structure having a winding shape, a laminated shape, or the like is widely used.
  • This electrolytic capacitor has the advantage that it is small and has a large capacity compared to plastic capacitors, mica capacitors, etc., and the dielectric breakdown voltage of the capacitor can be improved by thickening the oxide film on the anode.
  • the oxide film on the anode is made thick, the capacity of the electrolytic capacitor is reduced, and some of the advantages of small size and large capacity are lost.
  • studies have been made to increase the capacity of the cathode for the purpose of improving the capacity without reducing the dielectric breakdown voltage of the electrolytic capacitor.
  • a cathode having a conductive substrate and a conductive polymer layer provided on the surface of the conductive substrate, a substrate made of a valve metal, and the substrate.
  • a dielectric layer made of an oxide of the valve metal provided on the surface of the substrate, and the dielectric layer and the conductive polymer layer of the cathode are arranged so as to face each other with a space therebetween.
  • an electrolytic capacitor comprising an anode and an ion conductive electrolyte filled in the space, a voltage is applied between the anode and the cathode to form a conductive polymer layer from the cathode conductive substrate.
  • Patent Document 2 Japanese Patent Laid-Open No. 3-112116
  • Patent Document 3 Japanese Patent Laid-Open No. 283086
  • Example 9 and Patent Document 4 Japanese Patent Laid-Open No. 2000-269070
  • Embodiments 16 and 17 In the electrolytic capacitors of Patent Documents 2 to 4, no redox capacity is exhibited by the conductive polymer layer of the cathode. It is presumed that the supply of electrons to the conductive polymer layer in the electrolytic capacitors of these documents was insufficient to develop the redox capacity.
  • JP 2017-188655 A Japanese Patent Laid-Open No. 3-112116 Japanese Patent Laid-Open No. 7-283086 JP 2000-269070 A
  • FIG. 1 shows a method for forming a cathode for an electrolytic capacitor by forming a carbon vapor deposition film as an inorganic conductive layer on a natural oxide film of an aluminum foil and further forming a PEDOT layer having a thickness of 350 nm on the carbon vapor deposition film.
  • the above cathode as working electrode, activated carbon electrode as counter electrode, and silver-silver chloride electrode as reference electrode are introduced into an electrolytic solution in which amidinium salt of phthalic acid is dissolved in ⁇ -butyrolactone at a concentration of 20% by mass. And the result of having measured the cyclic voltammogram of the said cathode is shown. The measurement was performed at room temperature for 5 cycles at a scanning speed of 100 mV / s in the range of -1.2 V to +0.2 V with respect to the silver-silver chloride electrode.
  • FIG. 1 shows a cyclic voltammogram at the fifth cycle. In the cyclic voltammogram of FIG.
  • the electrolytic capacitor disclosed in Patent Document 1 is a capacitor utilizing the expression of this redox capacity.
  • the capacitance of this electrolytic capacitor varies with the voltage value applied to the capacitor, as understood from the mechanism of capacitance development described above. However, it has been found that the change in the capacitance of the capacitor is relatively small under normal use conditions. Yes.
  • a high capacity can be obtained by an electrolytic capacitor equipped with a cathode having a PEDOT layer
  • the capacitor capacity is confirmed after performing a high temperature load test in which a DC voltage is loaded on the electrolytic capacitor and left at 125 ° C. for a long time.
  • the capacitor capacity after the test measured under the condition of applying the bias voltage was lower than the capacitor capacity before the test, and the decrease in the capacitor capacity particularly in the high frequency region was remarkable. This change in capacitor capacity should be avoided because it limits the use of the capacitor under high temperature conditions.
  • an object of the present invention is to provide an electrolytic capacitor in which a decrease in capacity at the time of bias voltage load after experiencing a high temperature load test is suppressed based on the electrolytic capacitor disclosed in Patent Document 1, and a method for manufacturing the same. That is.
  • the inventors compared the cathode potentials under the bias voltage load for the capacitors before and after the high temperature load test in order to pursue the cause of the decrease in the capacity during the bias voltage load after experiencing the high temperature load test. As a result, it was found that the cathode potential at the time of bias voltage load shifted to the base side after experiencing the high temperature load test. This shift was considered to be caused by reduction (de-doping) of the PEDOT layer by continuously applying a potential to the cathode under high temperature conditions.
  • the decrease in capacity at the time of bias voltage load after experiencing the high temperature load test is caused by the cathode potential being shifted to the negative side by dedoping the PEDOT layer, and the cathode potential at the time of bias voltage load being oxidized (dope) of the PEDOT layer. This was considered to be caused by the fact that the PEDOT layer was less likely to be doped because the potential was lower than the potential at which the PEDOT occurs. Based on this idea, if a conductive polymer layer having an oxidation peak and a reduction peak on the base side of the cyclic voltammogram of the cyclic voltammogram of the PEDOT layer shown in FIG. It is expected that the decrease in capacity at the time of bias voltage load after experiencing the load test is suppressed.
  • a cathode having a homopolymer layer (PEtEDOT layer) of a compound (EtEDOT) in which ethyl (Et) is bonded to an ethylene group of EDOT is used as a working electrode, under the same conditions as the cyclic voltammogram of FIG.
  • the result of obtaining a cyclic voltammogram is shown in comparison with a cyclic voltammogram of a cathode having a PEDOT layer.
  • the PEDOT layer shows an oxidation peak at a position of -0.168V with respect to the silver-silver chloride electrode and a reduction peak at a position of -0.314V with respect to the silver-silver chloride electrode.
  • the PEtEDOT layer has an oxidation peak and a reduction peak on the base side of the PEDOT layer.
  • the decrease in the capacity at the bias voltage load after the test from the capacity at the bias voltage load before the test was not enough. It was not improved, and the decrease in the capacitor capacity in the low frequency region was rather severe (see Table 1).
  • a conductive polymer layer is formed by a copolymer of EDOT and a compound in which an electron-donating alkyl group is bonded to an ethylene group of EDOT, surprisingly, the conductive polymer layer is lower than the PEDOT layer. In addition to having an oxidation peak and a reduction peak on the side, it was found that the use of this conductive polymer layer suppresses a decrease in capacity at the time of bias voltage load after experiencing a high temperature load test.
  • the present invention firstly A cathode having a conductive substrate and a conductive polymer layer provided on the surface of the conductive substrate; A substrate made of a valve metal and a dielectric layer made of an oxide of the valve metal provided on the surface of the substrate, and the dielectric layer and the conductive polymer layer of the cathode open a space.
  • An anode arranged so as to oppose, An ion conductive electrolyte filling the space;
  • the conductive polymer layer in the cathode is composed of EDOT and the formula (I) (In the formula, R represents linear or branched alkyl having 1 to 10 carbon atoms, x represents an integer of 1 to 4, and when x represents an integer of 2 or more, each R is the same.
  • an electrolytic capacitor characterized in that it is composed of a copolymer of at least one compound selected from the group consisting of compounds represented by the following formula:
  • the compound represented by the formula (I) corresponds to a compound in which x substituents R are bonded to the ethylene group of EDOT.
  • the conductive polymer layer comprises at least one compound selected from the group consisting of compounds represented by formula (I) wherein x represents 1 and R represents linear alkyl having 1 to 10 carbon atoms, and EDOT.
  • the conductive polymer layer of the cathode needs to be in direct contact with the ion conductive electrolyte, but the dielectric layer of the anode may be in direct contact with the ion conductive electrolyte. Alternatively, it may be indirectly connected to the ion conductive electrolyte through another conductive material.
  • a cyclic voltammogram was obtained under the same conditions as those obtained for the cyclic voltammogram of FIG. 1 using a cathode having a copolymer layer of EDOT and EtEDOT (P (EDOT-EtEDOT) layer) as a working electrode.
  • P EDOT and EtEDOT
  • the results are shown in comparison with a cyclic voltammogram for a cathode with a PEDOT layer.
  • FIGS. 3 to 8 respectively show cyclic voltammograms for a cathode having a P (EDOT-EtEDOT) layer obtained by using a polymerization solution in which the molar ratio of EDOT to EtEDOT is adjusted to the ratio shown in each figure. ing.
  • the P (EDOT-EtEDOT) layer has an oxidation peak and a reduction peak on the base side of the PEDOT layer regardless of the difference in the molar ratio between EDOT and EtEDOT in the polymerization solution.
  • An electrolytic capacitor was prepared using a cathode having a P (EDOT-EtEDOT) layer, and a high-temperature load test was performed. From the capacity at the time of bias voltage load before the test, The drop was improved, and the drop in the capacitor capacity particularly in the high frequency region was remarkably improved (see Table 1).
  • FIGS. 3 to 8 show the results relating to the cathode in which the P (EDOT-EtEDOT) layer is a conductive polymer layer, but a copolymer of the compound represented by the formula (I) other than EtEDOT and EDOT. Similar results have been obtained by using.
  • the cathode is introduced into an electrolytic solution in which an amidinium salt of phthalic acid is dissolved in ⁇ -butyrolactone at a concentration of 20% by mass, and at room temperature with respect to a silver-silver chloride electrode.
  • a cathode having the copolymer layer as a conductive polymer layer is introduced into the electrolytic solution, and a cyclic voltammogram of the cathode is -1.
  • the potential of the reduction peak in the cyclic voltammogram at the 5th cycle is lower than -0.55V.
  • a certain cathode is provided, or a cathode in which the difference between the oxidation peak potential and the reduction peak potential in the cyclic voltammogram at the fifth cycle is in the range of 0.20 to 0.80 V. Within this range, the decrease in the capacity at the bias voltage load after the high-temperature load test from the capacity at the bias voltage load before the test is more significantly improved.
  • the contact resistance between the conductive substrate at the cathode and the conductive polymer layer provided on the surface is 3 ⁇ cm 2 or less, a voltage is applied between the anode and the cathode of the electrolytic capacitor. As a result, a sufficient amount of electrons is supplied to the conductive polymer layer that is in contact with the ion conductive electrolyte to develop the redox capacity. If the contact resistance is 1 ⁇ cm 2 or less, the redox capacity is It is preferable because it is expressed with high reliability.
  • the conductive substrate in the cathode may be composed of one conductive layer or a plurality of different conductive layers. In the case of multiple layers, each conductive layer may be in direct contact, and even if an insulating layer exists between the conductive layers, a part of the insulating layer may be destroyed and the conductive layers may be conducted. For example, it can be used as a conductive substrate.
  • the contact resistance between the conductive substrate and the conductive polymer layer in the cathode means a value measured by the method shown in FIG.
  • FIG. 9A is a diagram showing a measurement method when the conductive substrate is composed of one conductive layer
  • FIG. 9B is a measurement when the conductive substrate is composed of two conductive layers. It is the figure which showed the method.
  • a carbon paste (product type DY-200L-2, manufactured by Toyobo Co., Ltd.) is applied to the surface of the conductive polymer layer in a thickness of 5 to 10 ⁇ m and dried at 150 ° C. for 20 minutes.
  • a copper foil is fixed to the surface of the carbon layer via a silver paste (commercial model DW-250H-5, manufactured by Toyobo Co., Ltd.), and dried at 150 ° C. for 20 minutes.
  • FIG. 9A an AC impedance measurement is performed between the copper foil and the conductive substrate in a frequency range of 0.1 Hz to 100 kHz.
  • FIG. 9B the copper foil and the conductive substrate are measured.
  • the above-described AC impedance measurement is performed between the layer not in contact with the conductive polymer layer (first layer).
  • the value of the real component of the obtained Cole-Cole plot is the contact resistance between the conductive substrate and the conductive polymer layer.
  • the first layer is an aluminum foil
  • an aluminum oxide film is generally formed on the surface, but when a conductive layer is formed as the second layer on the surface of the aluminum oxide film, FIG.
  • the measurement method shown in b) is adopted.
  • the conductive substrate is composed of three or more conductive layers, the copper foil that is connected to the conductive polymer layer via the carbon paste and the silver paste by the above-described method and the conductive polymer layer are farthest from the conductive polymer layer.
  • the above-mentioned AC impedance measurement is performed with respect to the conductive layer at the position, and the value of the real component of the obtained Cole-Cole plot is the contact resistance between the conductive substrate and the conductive polymer layer at the cathode.
  • Aluminum foil can be preferably used for the conductive substrate in the cathode because it shows good corrosion resistance to the electrolyte.
  • a natural aluminum oxide film is generally present on the surface of the aluminum foil. After the film is completely removed by colliding ions such as carrier gas with the natural aluminum oxide film in a vacuum system, the surface of the aluminum foil is removed.
  • a protective conductive layer is formed for the purpose of improving water resistance and acid resistance, and an inorganic conductive layer is further formed on the protective conductive layer, so that each conductive layer is in direct contact with each other.
  • a conductive substrate can be preferably obtained.
  • the conductive polymer layer is provided on the surface of the inorganic conductive layer of the substrate. Since the conductive substrate has excellent adhesion between the aluminum foil and the inorganic conductive layer and exhibits low contact resistance, the redox capacity due to the conductive polymer layer of the cathode can be expressed with high reliability.
  • the conductive substrate includes an aluminum foil provided with an aluminum oxide film, and an inorganic conductive layer including an inorganic conductive material provided on the surface of the aluminum oxide film.
  • the inorganic conductive layer and the aluminum foil It is preferable that the substrate is electrically connected.
  • the conductive polymer layer is provided on the surface of the inorganic conductive layer.
  • the aluminum oxide film may be a natural oxide film or a chemical oxide film formed by chemical conversion treatment.
  • the inorganic conductive layer on the surface of the aluminum oxide film a part of the aluminum oxide film is broken and the inorganic conductive layer and the aluminum foil are made conductive, so that the conductive substrate and the conductive polymer layer in the cathode Can be adjusted to 1 ⁇ cm 2 or less, and the redox capacity by the conductive polymer layer of the cathode can be expressed with high reliability.
  • the present invention also provides A cathode having a conductive substrate and a conductive polymer layer provided on the surface of the conductive substrate; A substrate made of a valve metal and a dielectric layer made of an oxide of the valve metal provided on the surface of the substrate, and the dielectric layer and the conductive polymer layer of the cathode open a space.
  • An anode arranged so as to oppose, An ion conductive electrolyte filling the space;
  • a method for producing an electrolytic capacitor in which the cathode conductive polymer layer in contact with the ion conductive electrolyte exhibits a redox capacity by applying a voltage between the anode and the cathode.
  • a conductive polymer layer composed of a copolymer of EDOT and at least one compound selected from the group consisting of compounds represented by the above formula (I) on the surface of the conductive substrate;
  • An electrolyte filling step in which the conductive polymer layer of the cathode and the dielectric layer of the anode are opposed to each other by opening a space, and the space is filled with an ion conductive electrolyte; and
  • a voltage is applied between the cathode and the anode to supply electrons from the cathode conductive substrate to the conductive polymer layer, and the cathode is in contact with the ion conductive electrolyte.
  • the present invention relates to a method for producing an electrolytic capacitor, comprising a redox capacity inducing step for causing a molecular layer to exhibit a redox capacity.
  • the conductive polymer layer on the conductive substrate of the cathode may be formed by electrolytic polymerization, may be formed by chemical polymerization, or a dispersion containing conductive polymer particles. May be formed by applying to the surface of the conductive substrate, but is preferably formed by electrolytic polymerization.
  • electropolymerization a conductive polymer layer having excellent mechanical strength can be formed on the surface of the conductive substrate from a small amount of monomer in a short time, and a thin, dense and uniform conductive polymer layer can be obtained. be able to.
  • EDOT and at least one compound selected from the group consisting of the compounds represented by formula (I) are used in a molar ratio of 19: 1 to 1: 7, preferably 7: 1 to 1: It is preferable to use an electrolytic polymerization solution contained in the range of 3. Within this range, it is preferable to obtain a conductive polymer layer that leads to an electrolytic capacitor in which the decrease in the capacity at the time of bias voltage load after the high temperature load test from the capacity at the time of bias voltage load before the test is remarkably improved. it can.
  • the conductive polymer layer is at least one selected from the group consisting of EDOT and the compound represented by the formula (I).
  • EDOT electrolytic capacitor
  • the conductive polymer layer is at least one selected from the group consisting of EDOT and the compound represented by the formula (I).
  • the electrolytic capacitor of the present invention comprises a cathode having a conductive substrate and a conductive polymer layer provided on the surface of the conductive substrate, a substrate made of a valve metal, and the valve metal provided on the surface of the substrate.
  • An electrolytic capacitor comprising a conductive electrolyte, wherein a conductive polymer layer of the cathode that is in contact with the ion conductive electrolyte exhibits a redox capacity by applying a voltage between the anode and the cathode.
  • the conductive polymer layer in the cathode is EDOT and has the formula (I) (In the formula, R represents linear or branched alkyl having 1 to 10 carbon atoms, x represents an integer of 1 to 4, and when x represents an integer of 2 or more, each R is the same. Or at least one compound selected from the group consisting of compounds represented by the formula: a group consisting of compounds in which x substituents R are bonded to the ethylene group of EDOT. It is comprised by the copolymer of at least 1 sort (s) of compounds selected from these.
  • This conductive polymer layer improves the decrease in the capacity at the bias voltage load after the high temperature load test from the capacity at the bias voltage load before the test.
  • the electrolytic capacitor of the present invention can be manufactured by the following cathode formation step, anode formation step, electrolyte filling step, and redox capacity induction step. Hereinafter, each step will be described in detail.
  • the cathode in the electrolytic capacitor of the present invention has a conductive substrate and a conductive polymer layer provided on the surface of the conductive substrate.
  • a conductive substrate a substrate that functions as a current collector can be used without particular limitation as long as a sufficient amount of electrons can be supplied to develop a redox capacity in the conductive polymer layer.
  • the resistance of the conductive substrate 25Omucm 2 or less, preferably 6Omucm 2 or less, particularly preferably can be preferably used a conductive substrate is 0.25Omucm 2 or less.
  • the resistance of the conductive substrate means a value measured by the same method as described above with respect to the measurement of the contact resistance between the conductive substrate and the conductive polymer layer. That is, a carbon paste (product model DY-200L-2, manufactured by Toyobo Co., Ltd.) is applied to the surface of the conductive substrate on which the conductive polymer layer is to be formed, and dried at 150 ° C. for 20 minutes. Next, a copper foil is fixed to the surface of the carbon layer via a silver paste (commercial model DW-250H-5, manufactured by Toyobo Co., Ltd.), and dried at 150 ° C. for 20 minutes. Then, AC impedance measurement is performed in the frequency range of 0.1 Hz to 100 kHz between the copper foil and the conductive substrate. The value of the real component of the obtained Cole-Cole plot is the resistance of the conductive substrate.
  • a carbon paste product model DY-200L-2, manufactured by Toyobo Co., Ltd.
  • Such a conductive substrate may be composed of one conductive layer or a plurality of different conductive layers. In the case of multiple layers, each conductive layer may be in direct contact, and even if an insulating layer exists between the conductive layers, a part of the insulating layer may be destroyed and the conductive layers may be conducted.
  • it can be used as a conductive substrate.
  • valve metal foils such as aluminum, tantalum, niobium, titanium, zirconium, etc.
  • a foil having a surface area increased by application can be used as a conductive substrate, and an alloy such as an aluminum-copper alloy can also be used as a conductive substrate.
  • an inorganic conductive layer containing one or more inorganic conductive materials is formed on the surface of the valve metal foil after the natural oxide film is completely removed.
  • a chemical oxide film formed on the surface of the valve metal foil by a chemical conversion treatment using a chemical conversion solution such as an aqueous solution of ammonium borate, an aqueous solution of ammonium adipate, or an aqueous solution of ammonium phosphate.
  • a chemical conversion solution such as an aqueous solution of ammonium borate, an aqueous solution of ammonium adipate, or an aqueous solution of ammonium phosphate.
  • a part of the oxide film is destroyed and the conductive layer and the valve metal foil are made conductive so that they can be used as a conductive substrate. Can do.
  • the kind of inorganic conductive material for forming the inorganic conductive layer and the method for forming the inorganic conductive layer are special if a sufficient amount of electrons are supplied to cause the conductive polymer layer to exhibit redox capacity.
  • an inorganic conductive material such as carbon, titanium, platinum, gold, silver, cobalt, nickel, and iron is laminated on the oxide film by means such as vacuum deposition, sputtering, ion plating, coating, electrolytic plating, and electroless plating.
  • valve metal foil an aluminum foil or an aluminum foil subjected to an etching treatment as necessary is preferable because it shows good corrosion resistance against the electrolytic solution.
  • a natural aluminum oxide film is generally present. After the film is completely removed by colliding ions such as a carrier gas with the natural aluminum oxide film in a vacuum system, the aluminum foil is removed.
  • a protective conductive layer is formed on the surface of the foil for the purpose of improving water resistance and acid resistance, and an inorganic conductive layer is further formed on the protective conductive layer, so that each conductive layer is in direct contact with the conductive layer.
  • an electrically conductive substrate and an inorganic conductive layer is provided on the aluminum oxide film as described above even in the case of an aluminum foil having a natural aluminum oxide film or a chemical conversion aluminum oxide film. It is preferable to destroy a part of the aluminum oxide film to make the inorganic conductive layer and the aluminum foil conductive.
  • a titanium vapor deposition film as the inorganic conductive layer, atoms in the ambient atmosphere in the vapor deposition process can be included.
  • nitrogen nitride and carbon can be included to form a titanium nitride vapor deposition film and a titanium carbide vapor deposition film. Can do.
  • the inorganic conductive layer is preferably a layer containing at least one inorganic conductive material selected from the group consisting of carbon, titanium, titanium nitride, titanium carbide and nickel, because a cathode having excellent durability can be obtained. .
  • a titanium carbide vapor deposition film and a carbon vapor deposition film are preferable because they give a polymer film exhibiting stable characteristics in the following electropolymerization, and a carbon coating layer is preferable because of excellent productivity.
  • a conductive polymer layer is provided on the surface of the conductive substrate.
  • a conductive polymer layer is provided on the surface of the inorganic conductive layer.
  • the conductive polymer layer may be an electrolytic polymer film, a chemical polymer film, or a dispersion containing at least conductive polymer particles and a dispersion medium.
  • the formation of the electropolymerized film is performed by introducing the conductive substrate and the counter electrode into a polymerization solution containing at least a monomer, a supporting electrolyte, and a solvent, and applying a voltage between the conductive substrate and the counter electrode.
  • a plate or net of platinum, nickel, steel or the like can be used as the counter electrode.
  • an anion released from the supporting electrolyte is contained in the conductive polymer layer as a dopant.
  • a solvent that can dissolve a desired amount of the monomer and the supporting electrolyte and does not adversely affect the electrolytic polymerization can be used without any particular limitation.
  • examples include water, methanol, ethanol, isopropanol, butanol, ethylene glycol, acetonitrile, butyronitrile, acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, ⁇ -butyrolactone, methyl acetate, ethyl acetate, methyl benzoate, ethyl benzoate , Ethylene carbonate, propylene carbonate, nitromethane, nitrobenzene, sulfolane, dimethyl sulfolane.
  • solvents may be used alone or in combination of two or more. It is preferable to use a solvent containing water in an amount of 80% by mass or more of the whole solvent, in particular, a solvent composed only of water, because a dense and stable electropolymerized film can be obtained.
  • EDOT As a monomer and x (x represents an integer of 1 to 4) substituents R (R represents 1 to 10 carbon atoms) represented by the above formula (I). Represents a straight-chain or branched alkyl group in the formula (1), and an ethylene group of EDOT.
  • the compound represented by the above formula (I) contained in the polymerization solution together with EDOT may be one type of compound or two or more types of compounds.
  • substituent R examples include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3- Methylbutyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n- Decyl is mentioned.
  • each R may be the same or different.
  • a compound selected from the group consisting of compounds represented by the formula (I) wherein x represents 1 and R represents linear alkyl having 1 to 10 carbon atoms and EDOT are contained in the polymerization solution.
  • EDOT and a compound selected from the group consisting of compounds in which x represents 1 and R represents linear alkyl having 2 to 4 carbon atoms are contained in the polymerization solution. Particularly preferred.
  • a compound that releases a dopant contained in a conventional conductive polymer can be used without any particular limitation.
  • inorganic acids such as boric acid, nitric acid, phosphoric acid, tungstophosphoric acid, molybdophosphoric acid
  • organic acids such as acetic acid, oxalic acid, citric acid, ascot acid, tartaric acid, squaric acid, rhodizone acid, croconic acid, salicylic acid Methanesulfonic acid, dodecylsulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, 1,2-dihydroxy-3,5-benzenedisulfonic acid, naphthalenesulfonic acid, naphthalene disulfonic acid, propylnaphthalene
  • inorganic acids such as boric acid, nitric acid, phosphoric acid,
  • Polycarboxylic acids such as polyacrylic acid, polymethacrylic acid, and polymaleic acid
  • polysulfonic acids such as polystyrene sulfonic acid and polyvinyl sulfonic acid, and salts thereof can also be used as the supporting electrolyte.
  • borodisalicylic acid borodisuccinic acid, borodimalonic acid, borodisuccinic acid, borodiadipic acid, borodimaleic acid, borodiglycolic acid, borodilactic acid, borodihydroxyisobutyric acid, borodimalic acid, boroditartaric acid, borodicitric acid, borodiphthalic acid, borodihydroxybenzoic acid Boron complexes such as borodimandelic acid, borodibenzylic acid, formula (II) or formula (III) (In the formula, m means an integer of 1 to 8, preferably an integer of 1 to 4, particularly preferably 2, and n means an integer of 1 to 8, preferably an integer of 1 to 4, particularly preferably 2. And o means an integer of 2 or 3, and salts thereof can also be used as the supporting electrolyte.
  • the salt examples include alkali metal salts such as lithium salt, sodium salt and potassium salt, alkyl ammonium salts such as ammonium salt, ethyl ammonium salt and butyl ammonium salt, dialkyl ammonium salts such as diethyl ammonium salt and dibutyl ammonium salt, and triethyl ammonium salt.
  • alkali metal salts such as lithium salt, sodium salt and potassium salt
  • alkyl ammonium salts such as ammonium salt, ethyl ammonium salt and butyl ammonium salt
  • dialkyl ammonium salts such as diethyl ammonium salt and dibutyl ammonium salt
  • triethyl ammonium salt examples include trialkylammonium salts such as tributylammonium salt, and tetraalkylammonium salts such as tetraethylammonium salt and tetrabutylammonium salt.
  • These supporting electrolytes may be used alone or in combination of two or more.
  • the amount is less than the saturation solubility in the polymerization solution and for electrolytic polymerization.
  • the concentration is such that a sufficient current can be obtained, preferably at a concentration of 10 mmol or more per liter of the polymerization solution.
  • a conductive polymer layer containing a disalicylate ion as a dopant is preferable because the frequency dependency of the capacitor capacity is improved and a high capacity can be obtained even under high frequency conditions.
  • borodisalicylic acid and a salt thereof are dissolved as a supporting electrolyte in a solvent containing a large amount of water, preferably a solvent containing 80% by mass of water, particularly preferably a solvent consisting of only water, and an anionic surfactant. It is known that the frequency dependence of the capacitor capacity is further improved by using an electropolymerization solution in which the above monomer is solubilized or emulsified in the above solvent with the surfactant.
  • anionic surfactants examples include fatty acid salt type surfactants such as sodium laurate, sodium palmitate and sodium stearate, amino acid type surfactants such as sodium lauroyl glutamate, sodium lauroyl aspartate and Sodium lauroylmethylalanine, sulfate type surfactants, eg alkyl sulfates such as sodium dodecyl sulfate and sodium myristyl sulfate, alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate and sodium polyoxyethylene alkyl ether sulfate Ester salts, sulfonic acid type surfactants, eg alkane sulfonates such as sodium decane sulfonate and sodium dodecane sulfonate, octyl Alkyl benzene sulfonates such as sodium benzene sulfonate and sodium dodecyl
  • the anionic surfactant may be used alone or as a mixture of two or more, and is used in an amount sufficient to solubilize or emulsify a desired amount of monomer. It is preferable that the anionic surfactant is a sulfonic acid type surfactant and / or a sulfate ester type surfactant because an electrolytic capacitor having particularly excellent frequency characteristics can be obtained.
  • the electrolytic polymerization is performed by any one of a constant potential method, a constant current method, and a potential sweep method.
  • a potential of 1.0 to 1.5 V is suitable for the saturated calomel electrode
  • a current value of 1 to 10000 ⁇ A / cm 2 is suitable, and in the case of the potential sweep method, depending on the type of monomer, the range of 0 to 1.5 V with respect to the saturated calomel electrode is 5 to 200 mV / It is preferred to sweep at a rate of seconds.
  • the polymerization temperature is not strictly limited, but is generally in the range of 10 to 60 ° C.
  • the polymerization time is not strictly limited, but is generally in the range of 1 minute to 10 hours.
  • the chemical polymerization film is formed by preparing a solution in which both a monomer and an oxidizing agent are dissolved in a solvent, and applying this solution to the surface of the conductive substrate by brush coating, dripping coating, dip coating, spray coating, etc.
  • Examples of the solvent include water, methanol, ethanol, isopropanol, butanol, ethylene glycol, acetonitrile, butyronitrile, acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, ⁇ -butyrolactone, methyl acetate, ethyl acetate, methyl benzoate, benzoate Ethyl acid, ethylene carbonate, propylene carbonate, nitromethane, nitrobenzene, sulfolane, dimethyl sulfolane can be used. These solvents may be used alone or in combination of two or more.
  • EDOT and x (x represents an integer of 1 to 4) substituents R (R is a linear or branched group having 1 to 10 carbon atoms) represented by the above formula (I).
  • R is a linear or branched group having 1 to 10 carbon atoms
  • a compound in which EDOT is bonded to the ethylene group of EDOT As for the compound represented by the said formula (I) used together with EDOT, 1 type of compounds may be used and 2 or more types of compounds may be used. Also in chemical polymerization, it is preferable that EDOT is used in combination with a compound selected from the group consisting of compounds in which x represents 1 in formula (I) and R represents linear alkyl having 1 to 10 carbon atoms.
  • EDOT is used in combination with a compound selected from the group consisting of compounds represented by the formula (I) wherein x represents 1 and R represents linear alkyl having 2 to 4 carbon atoms.
  • the oxidizing agent include trivalent iron salts such as iron (III) p-toluenesulfonate, iron (III) naphthalenesulfonate, and iron (III) anthraquinonesulfonate, or ammonium peroxodisulfate and sodium peroxodisulfate.
  • a persulfate or the like can be used, and a single compound may be used, or two or more compounds may be used.
  • the polymerization temperature is not strictly limited, but is generally in the range of 0 to 200 ° C.
  • the polymerization time is not strictly limited, but is generally in the range of 1 minute to 10 hours.
  • a conductive polymer layer may be formed by applying a dispersion containing at least conductive polymer particles and a dispersion medium to the surface of the conductive substrate by means such as coating, dropping, and drying.
  • the dispersion medium in the dispersion include water, methanol, ethanol, isopropanol, butanol, ethylene glycol, acetonitrile, butyronitrile, acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, ⁇ -butyrolactone, methyl acetate, ethyl acetate, Methyl benzoate, ethyl benzoate, ethylene carbonate, propylene carbonate, nitromethane, nitrobenzene, sulfolane, dimethylsulfolane can be used, but water is preferably used as a dispersion medium.
  • the dispersion may contain EDOT as a monomer and x (x represents an integer of 1 to 4) substituents R (R represents 1 to 10 carbon atoms) represented by the above formula (I) in water.
  • purification means such as ultrafiltration, cation exchange, and anion exchange
  • the liquid obtained by the above-described chemical oxidative polymerization method or electrolytic polymerization method is filtered to separate aggregates, washed thoroughly and then added to water, ultrasonic dispersion treatment, high-speed fluid dispersion treatment, high-pressure dispersion treatment It can be obtained by performing a dispersion process such as.
  • the content of the conductive polymer particles in the dispersion is generally in the range of 1.0 to 3.0% by mass, and preferably in the range of 1.5 to 2.0% by mass. .
  • the thickness of the conductive polymer layer of the cathode is preferably in the range of 200 to 2450 nm.
  • the thickness of the conductive polymer layer is less than 200 nm, the high-temperature durability tends to decrease, and when the thickness of the conductive polymer layer is greater than 2450 nm, the temperature dependency of the capacity increases. This makes it difficult to contribute to the downsizing of electrolytic capacitors.
  • the conductive polymer layer of the cathode is preferably formed by electrolytic polymerization.
  • electropolymerization a conductive polymer layer having excellent mechanical strength can be formed on the surface of the conductive substrate from a small amount of monomer in a short time, and a thin, dense and uniform conductive polymer layer can be obtained. be able to.
  • EDOT and at least one compound selected from the group consisting of the compounds represented by formula (I) are used in a molar ratio of 19: 1 to 1: 7, preferably 7: 1 to 1: It is preferable to use a polymerization solution contained in the range of 3.
  • the ratio of the molar amount of EDOT to the sum of the molar amounts of two or more compounds represented by formula (I) is 19: 1. It is in the range of ⁇ 1: 7, preferably 7: 1 to 1: 3. Within this range, it is preferable to obtain a conductive polymer layer that leads to an electrolytic capacitor in which the decrease in the capacity at the time of bias voltage load after the high temperature load test from the capacity at the time of bias voltage load before the test is remarkably improved. it can.
  • a cathode is obtained by forming a conductive polymer layer on the surface of the conductive substrate by the above-mentioned process, and then amidinium salt of phthalic acid is added to ⁇ -butyrolactone at a concentration of 20 mass%
  • the cathode obtained in the electrolytic solution dissolved in 1 was introduced, and the first cathode capacity at 120 Hz at a potential of ⁇ 0.4 V with respect to the silver-silver chloride electrode was measured at room temperature, and then ⁇ Polarization from 0.4V to -1.0V in the cathode direction, then reversing the direction of polarization to polarize in the anode direction to -0.6V, and the second cathode capacity at 120Hz at a potential of -0.6V
  • a cathode in which the second capacity is 80% or more of the first capacity is provided. Within this range, the decrease in the capacity at the bias
  • a cathode is obtained by forming a conductive polymer layer on the surface of a conductive substrate by the above-described process, and then the obtained electrode is introduced into the electrolytic solution, Referring to the results of a test in which a cyclic voltammogram of the cathode was measured for 5 cycles at a scanning speed of 100 mV / s in the range of -1.2 V to +0.2 V with respect to a silver-silver chloride electrode.
  • a cathode whose reduction peak potential in the cyclic voltammogram at the cycle is lower than ⁇ 0.55 V is provided, or the difference between the oxidation peak potential and the reduction peak potential in the cyclic voltammogram at the fifth cycle is 0
  • a cathode in the range of 20 to 0.80V is provided. Within this range, the decrease in the capacity at the bias voltage load after the high-temperature load test from the capacity at the bias voltage load before the test is more significantly improved.
  • the contact resistance between the conductive substrate at the cathode and the conductive polymer layer provided on the surface is 3 ⁇ cm 2 or less, a voltage is applied between the anode and the cathode of the electrolytic capacitor.
  • a sufficient amount of electrons are supplied to the conductive polymer layer that is in contact with the ion conductive electrolyte to develop the redox capacity, but the redox capacity is reliable if the contact resistance is 1 ⁇ cm 2 or less.
  • the contact resistance is particularly preferably 0.06 ⁇ cm 2 or less because it exhibits good properties. It has been found that the lower the contact resistance, the better the frequency characteristics of the electrolytic capacitor according to the present invention.
  • the contact resistance is measured by the method described with reference to FIG. 9 after forming a conductive polymer layer on the surface of the conductive substrate by the above-described process.
  • the anode in the electrolytic capacitor of the present invention is composed of a base made of a valve metal such as aluminum, tantalum, niobium, titanium, or zirconium, and a dielectric made of an oxide of the valve metal provided on the surface of the base. And a body layer.
  • the substrate for the anode is preferably one in which the surface area is increased by subjecting the valve metal foil to a chemical or electrochemical etching treatment by a known method, and an aluminum foil subjected to the etching treatment is particularly preferred.
  • the dielectric layer on the surface of the substrate can be formed by a known method in which the substrate is subjected to a chemical conversion treatment using a chemical conversion solution such as an ammonium borate aqueous solution, an ammonium adipate aqueous solution, or an ammonium phosphate aqueous solution.
  • a chemical conversion solution such as an ammonium borate aqueous solution, an ammonium adipate aqueous solution, or an ammonium phosphate aqueous solution.
  • Electrolyte filling step In this step, the cathode having the conductive substrate obtained in the cathode forming step and the conductive polymer layer provided on the surface of the conductive substrate, and obtained in the anode forming step are obtained.
  • An anode having a base made of a valve metal and a dielectric layer made of an oxide of the valve metal provided on the surface of the base, a conductive polymer layer of the cathode and a dielectric layer of the anode After opening the space and arranging it so as to face each other, the space is filled with an ion conductive electrolyte.
  • an electrolytic solution used for a conventional electrolytic capacitor such as ⁇ -butyrolactone, ⁇ -valerolactone, ethylene glycol, diethylene glycol, propylene glycol, methyl cellosolve, ethylene glycol monomethyl ether, sulfolane, propylene carbonate, acetonitrile,
  • solvents such as water, benzoate, butyrate, phthalate, isophthalate, terephthalate, salicylate, tartrate, oxalate, malonate, malate, glutarate, adipate , Azelaate, maleate, fumarate, citrate, pyromellitic acid, trimellitic acid, 1,6-decanedicarboxylate, formate, acetate, glycolate, lactate, 1 -Naphthoate, mandelate, citraconic acid
  • the salt examples include amidinium salts, phosphonium salts, ammonium salts, amine salts, alkali metal salts and the like.
  • a carboxylate is preferable, and when a large amount of carboxylate is contained, the redox capacity by the conductive polymer layer of the cathode increases.
  • the content of the carboxylate in the electrolytic solution is at least a concentration of 0.1M, and is preferably a saturated dissolution amount in the electrolytic solution at most.
  • an amidinium salt is preferred because it significantly increases the redox capacity of the negative electrode conductive polymer layer.
  • amidinium salts include imidazolium salts such as 1,3-dimethylimidazolium salt, 1-ethyl-3-methylimidazolium salt, 1-methyl-2,3-dimethylimidazolium salt; Imidazolinium salts such as 4-tetramethylimidazolinium salt, 1,3-dimethyl-2,4-diethylimidazolinium salt, 1,2-dimethyl-3,4-diethylimidazolinium salt; 1,3 -Dimethyl-1,4,5,6-tetrahydropyrimidinium salt, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium salt, 1,3-dimethyl-1,4-dihydro Examples include pyrimidinium salts such as pyrimidinium salts; chain amidinium salts such as formamidinium salts, acetamidinium salts, and benzylamidinium salts.
  • the solvent of the electrolytic solution may be a single compound or a
  • electrolytic solutions may contain known additives in addition to the solvents and solutes described above.
  • phosphoric acid, phosphoric acid esters and the like are used for the purpose of improving the voltage resistance of the capacitor.
  • Acid compounds, boric acid compounds such as boric acid, sugar alcohols such as mannit, complex compounds of boric acid and sugar alcohol, polyoxyalkylene polyols such as polyethylene glycol, polyglycerin, and polypropylene glycol may be included.
  • nitro compounds such as nitrophenol, nitrobenzoic acid, nitroanisole, and nitrobenzyl alcohol may be included for the purpose of absorbing hydrogen generated rapidly particularly at high temperatures.
  • the gelling agent may be contained in these electrolyte solutions.
  • a room temperature molten salt (ionic liquid) can be used as the ion conductive electrolyte.
  • the capacitor element formed by laminating the strip-shaped cathode and the anode so that the conductive polymer layer of the cathode and the dielectric layer of the anode face each other with a separator interposed therebetween is wound on the capacitor element.
  • This step can be carried out by impregnating with an electrolytic solution or an ionic liquid.
  • the electrolytic solution or the ionic liquid is applied to a capacitor element formed by laminating the cathode and anode having a desired shape with a separator such that the conductive polymer layer of the cathode and the dielectric layer of the anode face each other.
  • This step can be carried out by impregnating.
  • Capacitor elements in which a plurality of sets of cathodes and anodes are alternately laminated so that the cathode conductive polymer layer and the anode dielectric layer face each other with the separator interposed therebetween are impregnated with the electrolytic solution or the ionic liquid.
  • the separator include woven or non-woven fabric made of cellulosic fibers, such as manila paper, kraft paper, esparto paper, hemp paper, cotton paper, rayon and mixed papers thereof, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate.
  • Polyester resins such as phthalates and their derivatives, polytetrafluoroethylene resins, polyvinylidene fluoride resins, vinylon resins, aliphatic polyamides, semi-aromatic polyamides, polyamide resins such as wholly aromatic polyamides, polyimide resins
  • the impregnation with the electrolytic solution or the ionic liquid may be performed after the capacitor element is accommodated in an exterior case having an opening.
  • the electrolytic solution can be made into a gel by heating after impregnating the capacitor element with the electrolytic solution.
  • the ion conductive electrolyte is filled. This step may be performed.
  • the ion conductive electrolyte in addition to the electrolyte solution or the ionic liquid, a gel electrolyte in which the electrolyte solution is absorbed in polyvinylidene fluoride, polyacrylonitrile or the like, or the above-described salt and polyethylene oxide
  • a solid electrolyte composed of a complex with a polymer compound such as polymethacrylate or polyacrylate can also be used.
  • a gel-like or solid electrolyte may be laminated on the conductive polymer layer of the cathode, and then the anode may be laminated on the electrolyte so that the dielectric layer is in contact therewith.
  • the conductive polymer layer of the cathode needs to be in direct contact with the ion conductive electrolyte, and the conductive polymer layer of the cathode is not in direct contact with the anode and is connected to the anode through the ion conductive electrolyte.
  • the dielectric layer of the anode may be in direct contact with the ion conductive electrolyte, or may be indirectly connected to the ion conductive electrolyte through another conductive material. Examples of other suitable conductive materials include a conductive polymer layer.
  • the conductive polymer layer can be formed on the surface of the anode dielectric layer by electrolytic polymerization or chemical polymerization after forming the anode in the anode forming step. It can also be formed by applying a dispersion containing at least a dispersion medium to the surface of the dielectric layer of the anode and drying.
  • the conductive polymer layer of the anode is not limited to the conductive polymer layer formed by the copolymer of the above-described EDOT and the compound represented by the formula (I), but a known conductive polymer such as a PEDOT layer. Layers can also be used.
  • the conductive layer and the conductive polymer layer of the cathode are arranged so as to face each other with a space therebetween. Thereafter, the space may be filled with an ion conductive electrolyte.
  • Redox capacity induction process A voltage is applied between the anode and cathode of the capacitor element housed and sealed in the outer case, and electrons are supplied from the cathode conductive substrate to the conductive polymer layer. Then, the redox capacity by the conductive polymer layer formed by the copolymer of EDOT of the said cathode which is contacting with the said ion conductive electrolyte, and the compound represented by Formula (I) expresses. For this reason, the capacity of the cathode is remarkably increased, and as a result, the capacity per unit volume of the electrolytic capacitor is remarkably increased.
  • ions in the ion conductive electrolyte are taken into the conductive polymer layer of the cathode.
  • the cathode has a conductive polymer layer formed of a copolymer of EDOT and a compound represented by the formula (I)
  • the bias voltage is loaded before the test of the capacity when the bias voltage is loaded after the high temperature load test
  • the drop from the capacity is improved.
  • Example 1 An aluminum foil obtained by etching only the surface layer was punched out to a projected area of 1 cm 2 , and a carbon deposited film was formed on the surface of the natural aluminum oxide film to obtain a conductive substrate. According to the method described above, a copper foil was fixed to the surface of this carbon vapor-deposited film via a carbon paste and a silver paste, and when AC impedance measurement was performed between the copper foil and the aluminum foil, the resistance of the conductive substrate was It was 5.3 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • EDOT and a compound (EtEDOT) in which R represents ethyl (Et) and x represents 1 in the formula (I) were mixed at a molar ratio of EDOT: EtEDOT of 19: 1 and a total of 0.03M.
  • the conductive substrate (working electrode) and a counter electrode of SUS mesh having an area of 10 cm 2 are introduced into the above-described polymerization solution for electrolytic polymerization, and constant current electrolytic polymerization is performed for 2 minutes under the condition of 500 ⁇ A / cm 2. went.
  • the working electrode after polymerization is washed with water and then dried at 100 ° C. for 30 minutes to obtain a cathode in which a P (EDOT-EtEDOT) layer as a conductive polymer layer is formed with a thickness of 350 nm on a carbon vapor deposition film. It was.
  • the thickness of the conductive polymer layer was determined by changing the thickness of the conductive polymer layer obtained in each experiment by performing constant current electrolytic polymerization under conditions of 500 ⁇ A / cm 2 multiple times at different times. Measured using a force microscope or a step meter to derive a relational expression between the thickness of the conductive polymer layer and the charge amount, and then used the derived relational expression to determine the charge amount of electrolytic polymerization by the thickness of the conductive polymer layer. It is the value obtained by converting to.
  • a copper foil is fixed to the surface of the cathode P (EDOT-EtEDOT) layer with a carbon paste and a silver paste in accordance with the method described with reference to FIG.
  • the contact resistance between the conductive substrate and the P (EDOT-EtEDOT) layer was 7.3 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • the cathode, an activated carbon electrode having an area of 12 cm 2 as a counter electrode, and a silver-silver chloride reference electrode as a reference electrode were introduced, and at room temperature, ⁇ 0.4 V with respect to the silver-silver chloride electrode.
  • the second cathode capacity at 120 Hz at a potential of ⁇ 0.6 V was measured, and then the ratio of the second cathode capacity to the first cathode capacity was calculated.
  • a conductive substrate having a carbon deposited film formed on the surface of a natural aluminum oxide film is obtained, and the obtained conductive substrate and the counter electrode are polymerized for the electrolytic polymerization.
  • constant current electropolymerization was carried out for 2 minutes under the condition of 500 ⁇ A / cm 2 , the working electrode after polymerization was washed with water, dried at 100 ° C. for 30 minutes, and P (EDOT on the carbon deposited film)
  • a negative electrode having a thickness of -EtEDOT) layer of 350 nm was obtained.
  • an aluminum oxide film was formed by chemical conversion treatment on the surface of the aluminum foil whose surface area was increased by etching treatment, and then punched to a projected area of 2.1 cm 2 to obtain an anode (capacity: 370 ⁇ F / cm 2 ).
  • a capacitor element in which the cathode and the anode are laminated via a cellulose separator is prepared, and this element is impregnated with an electrolytic solution in which an amidinium salt of phthalic acid is dissolved in ⁇ -butyrolactone at a concentration of 20% by mass. And laminated pack.
  • a re-chemical conversion treatment was performed by applying a voltage of 3.35 V for 60 minutes at a temperature of 105 ° C. to obtain a plate-type electrolytic capacitor.
  • This capacitor was subjected to a high temperature load test in which a DC voltage of 2.4 V was applied for 1060 hours at 125 ° C. after applying a bias voltage of 2.9 V under room temperature conditions and measuring a capacitor capacity at 120 Hz and 10 kHz. Later, a bias voltage of 2.9 V was loaded again at room temperature, and the capacitor capacity at 120 Hz and 10 kHz was measured.
  • Example 2 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. To this solution, EDOT and a compound (EtEDOT) in which R represents ethyl (Et) and x represents 1 in the formula (I) are in a molar ratio of EDOT: EtEDOT of 9: 1 and a total of 0.03M. Electrolysis in which 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT and EtEDOT were solubilized in water with sodium butylnaphthalenesulfonate A polymerization solution for polymerization was obtained.
  • Example 2 The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1.
  • the contact resistance between the conductive substrate and the P (EDOT-EtEDOT) layer was 5.9 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • Example 3 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. To this solution, EDOT and a compound (EtEDOT) in which R represents ethyl (Et) and x represents 1 in the formula (I) are in a molar ratio of EDOT: EtEDOT of 7: 1 and a total of 0.03M. Electrolysis in which 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT and EtEDOT were solubilized in water with sodium butylnaphthalenesulfonate A polymerization solution for polymerization was obtained.
  • Example 2 The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1.
  • the contact resistance between the conductive substrate and the P (EDOT-EtEDOT) layer was 8.3 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • Example 4 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. To this solution, EDOT and a compound (EtEDOT) in which R represents ethyl (Et) and x represents 1 in the formula (I) were mixed at a molar ratio of EDOT: EtEDOT of 3: 1 and a total of 0.03M. Electrolysis in which 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT and EtEDOT were solubilized in water with sodium butylnaphthalenesulfonate A polymerization solution for polymerization was obtained.
  • Example 2 The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1.
  • the contact resistance between the conductive substrate and the P (EDOT-EtEDOT) layer was 5.4 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • Example 5 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. To this solution, EDOT and a compound (EtEDOT) in which R represents ethyl (Et) and x represents 1 in the formula (I) were mixed at a molar ratio of EDOT: EtEDOT of 1: 1 and a total of 0.03M. Electrolysis in which 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT and EtEDOT were solubilized in water with sodium butylnaphthalenesulfonate A polymerization solution for polymerization was obtained.
  • Example 2 The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1.
  • the contact resistance between the conductive substrate and the P (EDOT-EtEDOT) layer was 1.0 ⁇ 10 ⁇ 2 ⁇ cm 2 .
  • Example 6 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. To this solution, EDOT and a compound (EtEDOT) in which R represents ethyl (Et) and x represents 1 in the formula (I), the molar ratio of EDOT: EtEDOT was 1: 3 and a total of 0.03M. Electrolysis in which 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT and EtEDOT were solubilized in water with sodium butylnaphthalenesulfonate A polymerization solution for polymerization was obtained.
  • Example 2 The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1.
  • the contact resistance between the conductive substrate and the P (EDOT-EtEDOT) layer was 7.6 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • Example 7 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. To this solution, EDOT and a compound (BuEDOT) in which R represents n-butyl (Bu) and x represents 1 in the formula (I), the molar ratio of EDOT: BuEDOT was 3: 1 and the total amount was 0.1. It was introduced at a concentration of 03M, 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT and BuEDOT were solubilized in water with sodium butylnaphthalenesulfonate. A polymerization solution for electrolytic polymerization was obtained.
  • Example 2 The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1.
  • the contact resistance between the conductive substrate and the P (EDOT-BuEDOT) layer was 2.2 ⁇ 10 ⁇ 2 ⁇ cm 2 .
  • Comparative Example 1 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. EDOT was introduced into this solution at a concentration of 0.03M, 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EDOT was added with sodium butylnaphthalenesulfonate. A polymerization solution for electrolytic polymerization solubilized in water was obtained. The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1. The contact resistance between the conductive substrate and the PEDOT layer was 1.6 ⁇ 10 ⁇ 3 ⁇ cm 2 .
  • Comparative Example 2 Distilled water (50 mL) was introduced into a glass container and heated to 40 ° C. EtEDOT was introduced into this solution at a concentration of 0.03M, 0.04M ammonium borodisalicylate and 0.04M sodium butylnaphthalenesulfonate were added and stirred, and EtEDOT was added with sodium butylnaphthalenesulfonate. A polymerization solution for electrolytic polymerization solubilized in water was obtained. The same procedure as in Example 1 was repeated except that this polymerization solution was used instead of the electrolytic solution for electrolytic polymerization used in Example 1. The contact resistance between the conductive substrate and the PEtEDOT layer was 1.0 ⁇ 10 ⁇ 2 ⁇ cm 2 .
  • Table 1 shows capacitor capacities (Cap) at the time of bias voltage load at 120 Hz and 10 kHz measured before the high temperature load test, and after the high temperature load test, for the electrolytic capacitors obtained in Examples 1 to 7 and Comparative Examples 1 and 2.
  • capacitance at the time of the bias voltage load in 120 Hz and 10 kHz measured, and the change rate of the capacitor capacity at the time of the bias voltage load at 120 Hz and 10 kHz before and after a high temperature load test are shown.
  • the capacitors of Comparative Example 1 and Comparative Example 2 showed stable capacity even after the high temperature load test, but the capacitor of Comparative Example 1 was particularly at 10 kHz after the high temperature load test, and the capacitor of Comparative Example 2 was 120 Hz after the high temperature load test. A significant decrease in capacity was observed at any of 10 kHz.
  • the electrolytic capacitors of Examples 1 to 7 showed a stable capacity even after the high temperature load test, and the decrease in the capacity after the high temperature load test from the capacity before the test. Compared with the capacity reduction of the capacitor of Comparative Example 1, it was remarkably improved.
  • Table 2 shows the potential of the reduction peak (Ered) obtained from the cyclic voltammogram of the fifth cycle for the cathodes of Examples 1 to 7 and Comparative Examples 1 and 2 that showed stable capacity even after the high temperature load test. ), The oxidation peak potential (Eox), and the difference between the oxidation peak potential and the reduction peak potential ( ⁇ Ep), starting from ⁇ 0.4 V to the silver-silver chloride electrode—1.
  • Cathode capacity at 120 Hz at the starting point of -0.4 V measured by polarization in the cathode direction to 0 V and then reversing the direction of polarization and polarization in the anode direction to -0.6 V (first cathode capacity) (C ( ⁇ 0.4 V)), cathode capacity at 120 Hz at the final point of ⁇ 0.6 V (second cathode capacity) (C ( ⁇ 0.6 V)), and second with respect to the first cathode capacity
  • the ratio of the cathode capacity is shown.
  • the cathodes in Examples 1 to 7 having a P (EDOT-EtEDOT) layer or P (EDOT-BuEDOT) layer were compared with the cathode of Comparative Example 1 having a PEDOT layer, and the oxidation peak and It shows a reduction peak, and it can be seen that the difference between the oxidation peak potential and the reduction peak potential is enlarged. Further, the cathodes in Examples 1 to 7 having the P (EDOT-EtEDOT) layer or the P (EDOT-BuEDOT) layer are 120 Hz at ⁇ 0.6 V compared to the cathode of the comparative example 1 having the PEDOT layer.
  • the cathode capacity (second cathode capacity) (C ( ⁇ 0.6 V)) is particularly increased, and the cathode capacity (first cathode capacity) at 120 Hz at ⁇ 0.4 V (C ( ⁇ 0.4 V)) ) Ratio of the second cathode capacity to 80%.
  • the capacitors of Examples 1 to 7 show a high capacity before the high temperature load test, and the capacity at the bias voltage load after the high temperature load test before the test.
  • an electrolytic capacitor which is small and has a large capacity and can withstand use at high temperatures.

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JP2023034887A (ja) * 2021-08-31 2023-03-13 株式会社東芝 電解コンデンサの製造方法、電解コンデンサ及び電解コンデンサの製造装置

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JP2006352172A (ja) * 2006-09-29 2006-12-28 Nippon Chemicon Corp 固体電解コンデンサとその製造方法
WO2015107894A1 (ja) * 2014-01-16 2015-07-23 パナソニックＩｐマネジメント株式会社 電解コンデンサおよびその製造方法
WO2015129515A1 (ja) * 2014-02-27 2015-09-03 テイカ株式会社 導電性高分子製造用酸化剤兼ドーパント、その溶液、それらのいずれかを用いて製造した導電性高分子およびその導電性高分子を電解質として用いた電解コンデンサ
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JP2006352172A (ja) * 2006-09-29 2006-12-28 Nippon Chemicon Corp 固体電解コンデンサとその製造方法
WO2015107894A1 (ja) * 2014-01-16 2015-07-23 パナソニックＩｐマネジメント株式会社 電解コンデンサおよびその製造方法
WO2015129515A1 (ja) * 2014-02-27 2015-09-03 テイカ株式会社 導電性高分子製造用酸化剤兼ドーパント、その溶液、それらのいずれかを用いて製造した導電性高分子およびその導電性高分子を電解質として用いた電解コンデンサ
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US11929214B2 (en) * 2019-12-17 2024-03-12 Nippon Chemi-Con Corporation Hybrid electrolytic capacitor and method for manufacturing same

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