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WO2023276436A1 - Électrode pour dispositif électrochimique, et dispositif électrochimique - Google Patents

Électrode pour dispositif électrochimique, et dispositif électrochimique Download PDF

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Publication number
WO2023276436A1
WO2023276436A1 PCT/JP2022/019065 JP2022019065W WO2023276436A1 WO 2023276436 A1 WO2023276436 A1 WO 2023276436A1 JP 2022019065 W JP2022019065 W JP 2022019065W WO 2023276436 A1 WO2023276436 A1 WO 2023276436A1
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Prior art keywords
active layer
electrode
electrochemical device
porous carbon
carbon particles
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Japanese (ja)
Inventor
信敬 武田
和晃 山下
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Panasonic Intellectual Property Management Co Ltd
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Panasonic Intellectual Property Management Co Ltd
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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
    • H01G11/22—Electrodes
    • H01G11/24—Electrodes characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials

Definitions

  • the present disclosure relates to electrodes for electrochemical devices and electrochemical devices.
  • An example of an electrochemical device used as an electricity storage device includes a pair of electrodes and an electrolytic solution. At least one of the pair of electrodes contains an active material capable of adsorbing and desorbing ions. Electrochemical devices such as electric double layer capacitors have a longer life, faster charging capability, and superior output characteristics than secondary batteries. Therefore, electrochemical devices are widely used as backup power sources and the like.
  • Patent Document 1 International Publication No. 2006/068291
  • an electric double layer capacitor comprising an electrode made of activated carbon, a separator, and a non-aqueous electrolytic solution, wherein the activated carbon has an average particle diameter of 0.1 ⁇ m or more.
  • An electric double layer capacitor characterized by having a thickness of less than 0 ⁇ m.”.
  • Patent Document 2 Patent No. 65695266 describes, "Porous carbon powder having an average particle size of less than 100 nm and fibrous carbon are dispersed in a solution obtained by removing the solvent by filtration under reduced pressure.
  • An electrode wherein the particle size distribution of carbon powder and fibrous carbon aggregates constituting the electrode has a single peak, and the particle size distribution has a particle size of 50% cumulative value D50 and a particle size of 90% cumulative value D90
  • Patent Literature 2 describes the ratio of mesopores to the pores in the porous carbon powder.
  • one object of the present disclosure is to provide an electrochemical device capable of achieving both high capacity (for example, high capacity at low temperature) and high reliability, and an electrode used therein. be.
  • the active layer contains porous carbon particles and a binder, the average particle diameter of the porous carbon particles is in the range of 0.5 ⁇ m to 1.0 ⁇ m, and the binder comprises carboxymethyl cellulose and carboxymethyl cellulose.
  • the active layer contains at least one carboxymethylcellulose selected from salts of methylcellulose and a rubber, and when the active layer is subjected to thermogravimetric analysis, the amount of mass reduction based on the carboxymethylcellulose and the rubber is the same as that of the active layer. 8.2% or more and 21.3% or less of the mass of
  • the electrochemical device includes a pair of electrodes and an electrolytic solution, and at least one of the pair of electrodes is the electrochemical device electrode according to any one of claims 1 to 4.
  • an electrochemical device capable of achieving both high capacity and high reliability and electrodes used therein are obtained.
  • FIG. 1 is a perspective cut-away view of an electrochemical device according to one embodiment of the present disclosure
  • An electrochemical device electrode is an electrode including an active layer.
  • the electrode may be hereinafter referred to as "electrode (E)".
  • the active layer contained in the electrode (E) contains porous carbon particles and a binder.
  • the average particle size of the porous carbon particles is in the range of 0.5 ⁇ m to 1.0 ⁇ m.
  • the binder contains at least one kind of carboxymethyl cellulose selected from carboxymethyl cellulose and salts of carboxymethyl cellulose, and rubber.
  • Electrode (E) may comprise an active layer and a current collector carrying the active layer.
  • the current collector is not particularly limited, and known current collectors used for electrodes of electrochemical devices may be used.
  • Examples of current collectors include metal foils such as aluminum foil.
  • the surface of the current collector is preferably roughened.
  • the roughening method is not particularly limited, and the surface may be roughened by a known method (eg, etching method).
  • the electrode (E) may further include an aluminum foil (current collector) supporting the active layer, and the surface of the aluminum foil may be roughened.
  • the capacitance of the aluminum foil (current collector) may be 30 ⁇ F/cm 2 or more.
  • the upper limit of the capacitance is not particularly limited, but may be 120 ⁇ F/cm 2 or less.
  • the capacitance ( ⁇ F/cm 2 ) is the capacitance per unit area (1 cm 2 ) of the current collector.
  • the capacitance ( ⁇ F/cm 2 ) of the current collector is the sum of the capacitance on one side of the current collector and the capacitance on the other side. That is, if the capacitance of a current collector whose both surfaces are similarly roughened is X ⁇ F/cm 2 , the capacitance of one side is substantially 0.5 X ⁇ F/cm 2 .
  • the capacitance ( ⁇ F/cm 2 ) of aluminum foil (current collector) is measured by the following method.
  • a test piece of aluminum foil is prepared.
  • the shape and size of the test piece are not particularly limited, it has a portion to be measured and a lead portion for measuring capacitance.
  • the portion to be measured is the portion that is immersed in the measurement solution.
  • the shape and size of the portion to be measured are not particularly limited, a rectangular shape is desirable, and has dimensions of, for example, 10 mm ⁇ 50 mm.
  • the withdrawn portion is the portion that is not immersed in the measurement solution.
  • the drawn-out portion may be a portion that is cut out integrally with the portion to be measured.
  • the shape and size of the drawer part are arbitrary.
  • the measurement solution an aqueous solution of 80 g of ammonium pentaborate dissolved in 1 L of water is used.
  • the capacitance measuring device complies with JIS C 5101-1. The accuracy is ⁇ 2% of the measured value, the measurement frequency is 120 Hz ⁇ 5%, and the measurement voltage is 0.5 Vrms or less.
  • a measuring tank containing a measuring solution is a glass tall beaker with a capacity of 200 mL or 300 mL conforming to JIS R 3503. Set the temperature of the measurement solution to 30 ° C.
  • the active layer contains porous carbon particles as an active material and a binder as essential components.
  • the active layer may optionally contain other components such as a conductive agent.
  • conductive agents include carbon black such as acetylene black.
  • Electrode (E) utilizes such a phenomenon.
  • Electrode (E) uses porous carbon particles with a smaller average particle size than conventional general electrodes. Also, as the binder, a unique combination of carboxymethyl celluloses and rubber is selected, and the content thereof is limited. Many substances are known to be used as binders for electrodes of electrochemical devices, and there are countless combinations thereof. As a result of investigations, the inventors of the present application have found that by combining porous carbon particles with a small average particle size and a binder with a specific combination and a specific content rate, it is possible to achieve both high capacity and high reliability. newly found that it is possible. The present disclosure is based on this new finding.
  • the active layer When forming the active layer, the active layer may be formed so that the total ratio S of carboxymethyl celluloses and rubber in the active layer is 8.2% by mass or more.
  • the proportion S may be 21.3% by mass or less.
  • the proportion S may be in the range from 8.2 to 21.3% by weight.
  • the binder contains at least one kind of carboxymethylcellulose selected from carboxymethylcellulose and salts of carboxymethylcellulose.
  • carboxymethylcellulose selected from carboxymethylcellulose and salts of carboxymethylcellulose.
  • salts of carboxymethylcellulose include alkali metal salts (eg, sodium salts) of carboxymethylcellulose.
  • a preferred example of carboxymethylcelluloses is carboxymethylcellulose.
  • Examples of rubber contained in the binder include styrene-butadiene rubber (SBR) and acrylic rubber.
  • SBR styrene-butadiene rubber
  • acrylic rubber examples include acrylic rubber.
  • combinations of carboxymethyl celluloses and rubbers are particularly preferred. That is, the rubber is preferably styrene-butadiene rubber.
  • the mass of carboxymethylcelluloses may be greater than the mass of styrene-butadiene rubber.
  • the weight of carboxymethylcelluloses may range from 1.1 to 4.5 times the weight of styrene-butadiene rubber. According to this configuration, a particularly high effect can be obtained.
  • the binder improves the adhesion between the porous carbon particles and the adhesion between the porous carbon particles and the current collector.
  • Carboxymethyl celluloses are considered to be highly effective in increasing adhesion between porous carbon particles. In this respect, when porous carbon particles having a small average particle size are used, it is particularly important to increase the proportion of carboxymethyl celluloses.
  • the active layer may contain binders other than carboxymethylcelluloses and rubber.
  • the mass of other binders is usually 10% or less (eg, 5% or less) of the total mass of carboxymethylcelluloses and rubber.
  • examples of other binders include polytetrafluoroethylene (PTFE) and the like.
  • PTFE polytetrafluoroethylene
  • a preferred example of the active layer contains only carboxymethylcelluloses and rubber as binders.
  • the average particle size of the porous carbon particles may be 0.5 ⁇ m or more or 0.6 ⁇ m or more, and may be 1.0 ⁇ m or less or 0.8 ⁇ m or less.
  • the average particle size means a particle size (median diameter, D50) at which the volume integrated value is 50% in the volume-based particle size distribution measured by the laser diffraction/scattering method.
  • the ratio B/A of the cumulative volume A of pores having a pore diameter of 1 nm or more and less than 2 nm to the cumulative volume B of pores having a pore diameter of 2 nm or more and 50 nm or less may be 1 or more (eg, 1.2 or more).
  • the ratio B/A may be 1 or more (eg, 1.2 or more) and 1.5 or less.
  • pores having a pore diameter of 1 nm or more and less than 2 nm may hereinafter be referred to as "pore a" or “micropore”.
  • pore b a pore having a pore diameter of 2 nm or more and 50 nm or less may hereinafter be referred to as “pore b” or “mesopore”.
  • the cumulative volume A mentioned above is the total volume (cm 3 ) of pores a per 1 g of porous carbon particles.
  • the above cumulative volume B is the total volume (cm 3 ) of pores b per 1 g of porous carbon particles.
  • the volume-based particle size frequency distribution is a volume-based particle size distribution in which the vertical axis indicates the frequency and the horizontal axis indicates the particle size.
  • the porous carbon particles are, for example, activated carbon.
  • Porous carbon particles can be produced, for example, by heat-treating a raw material to carbonize it, and then activating the resulting carbide to make it porous.
  • the carbide may be crushed and granulated before the activation treatment.
  • the porous carbon particles obtained by the activation treatment may be pulverized. After the pulverization treatment, a classification treatment may be performed. Examples of the activation treatment include gas activation using a gas such as water vapor, and chemical activation using an alkali such as potassium hydroxide.
  • Raw materials for the porous carbon particles include, for example, wood, coconut shells, pulp effluent, coal or coal-based pitch obtained by thermal decomposition thereof, heavy oil or petroleum-based pitch obtained by thermal decomposition thereof, phenolic resin, petroleum-based Coke, coal-based coke, and the like. Among them, petroleum-based coke and coal-based coke are preferred as raw materials. In this case, porous carbon particles having a large ratio of pores b are easily obtained by the activation treatment.
  • the porous carbon particles may be pulverized. However, if the pulverization treatment is performed excessively, B/A may become larger than 1.5.
  • a ball mill, jet mill, or the like is used for pulverization.
  • the pore distribution and particle size distribution of the porous carbon particles can be adjusted by the raw material, heat treatment temperature, activation temperature in gas activation, degree of pulverization, and the like. Also, two types of porous carbon particles made from different raw materials may be mixed to adjust the pore size distribution and particle size distribution of the porous carbon particles.
  • the float characteristic is an index of the degree of deterioration of an electrochemical device when float charging is performed using an external DC power supply to maintain a constant voltage. It can be said that the smaller the decrease in capacity during float charging and the smaller the increase in internal resistance, the better the float characteristics.
  • the pores a mainly contribute to the specific surface area of the porous carbon particles and mainly affect the capacity (especially the initial capacity).
  • the pores b mainly contribute to the mobility of ions in the electrolyte within the pores, and mainly affect the float characteristics and internal resistance.
  • the pore diameter is 2 nm or more, ions in the electrolytic solution are easily diffused in the pores, and the pores are less likely to be clogged. In pores with a pore diameter of 2 nm or more, good ion movement is ensured even at low temperatures.
  • the ratio of pores a increases and the ratio of pores b decreases.
  • the ions in the electrolytic solution are less likely to diffuse in the pores, and the pores are more likely to be clogged.
  • the pores may be easily clogged by decomposition products of the electrolytic solution. These may increase the internal resistance and degrade the float characteristics.
  • the ratio B/A exceeds 1.5, the ratio of pores a decreases and the ratio of pores b increases. As a result, the electrode density is reduced and the initial capacity may be reduced at low temperatures.
  • the total ratio of the cumulative volumes A and B to the total pore volume is, for example, 87%. It is preferable that it is 90% or less. In this case, many pores a and b are distributed, and a large capacity and excellent float characteristics are likely to be obtained.
  • the BET specific surface area of the porous carbon particles may be in the range of 1500-2500 m 2 /g (for example, the range of 1790-2240 m 2 / g).
  • the pore distribution of porous carbon particles is measured by a gas adsorption method. Nitrogen gas is used as the gas. As a measuring device, for example, an automatic specific surface area/pore size distribution measuring device "Tristar II 3020" manufactured by Shimadzu Corporation is used. In order to remove impurities, the sample of porous carbon particles is subjected to pretreatment such as heat evacuation (for example, 50 mTorr or less at 250° C.) before the measurement.
  • the BJH method Barrett-Joyner-Halenda method
  • Harkins & Jura formula is used in the BJH method.
  • the above cumulative volumes A and B are determined using the cumulative pore volume distribution obtained by the BJH method.
  • the BET specific surface area of the porous carbon particles is measured by the gas adsorption method (BET single-point method). Nitrogen gas is used as the gas.
  • the measuring device for example, an automatic specific surface area/pore size distribution measuring device "Tristar II 3020" manufactured by Shimadzu Corporation is used.
  • the particle size distribution of porous carbon particles is measured by a laser diffraction/scattering method.
  • a laser diffraction/scattering particle size distribution measuring device “MT3300EXII” manufactured by Microtrack Co., Ltd. is used as a measuring device.
  • the mass of the binder in the active layer is determined by thermogravimetric analysis (TGA). Specifically, the mass of the binder can be measured by peeling off the active layer of the electrode and subjecting the powder constituting the active layer to thermogravimetric analysis.
  • TGA thermogravimetric analysis
  • NEXTA STA300 Hitachi High-Tech Co., Ltd.
  • the sample to be analyzed is dried and then subjected to thermogravimetric analysis. Specifically, samples can be dried at 130° C. for 2 hours before analysis.
  • the type of binder in the electrode can be identified, for example, by pyrolysis gas chromatography/mass spectrometry (pyrolysis GC/MS).
  • pyrolysis gas chromatography/mass spectrometry pyrolysis GC/MS
  • devices that can be used include HP 5890 Series II GC with HP5972 MSD & 7673 Autosampler (Hewlett Packard) and Hewlett Packard 5890 GC Series II with ALS 7673 Controller and PC.
  • the manufacturing method of the electrode (E) is not particularly limited, and known methods may be applied.
  • the above-described porous carbon particles and binder are used.
  • the materials are mixed so that the proportions of the components in the active layer are in the proportions given above.
  • the mass ratio in the slurry is reflected in the mass ratio in the active layer.
  • the dispersion medium is not particularly limited, and a common dispersion medium (eg, water) may be used.
  • the slurry is applied to the surface of the current collector to form a coating film, and the coating film is rolled to form an active layer.
  • the electrode (E) can be produced.
  • An electrochemical device includes a pair of electrodes and an electrolytic solution. At least one of the pair of electrodes is the electrode (E) according to the present embodiment.
  • Electrochemical devices include electric double layer capacitors (EDLC) and lithium ion capacitors (LIC).
  • EDLC electric double layer capacitors
  • LIC lithium ion capacitors
  • the electrochemical device is an EDLC
  • at least one of the pair of electrodes can be the electrochemical device electrode described above.
  • the electrochemical device is a LIC
  • one of the pair of electrodes (positive electrode) can be the above-described electrochemical device electrode
  • the other of the pair of electrodes can be the negative electrode used in a lithium ion secondary battery.
  • a negative electrode used in a lithium ion secondary battery includes, for example, a negative electrode active material (such as graphite) capable of intercalating and deintercalating lithium ions.
  • the electrolyte contains a solvent (non-aqueous solvent) and an ionic substance.
  • Ionic substances are dissolved in a solvent and include cations and anions.
  • the ionic substance may include, for example, a low melting point compound (ionic liquid) that can exist as a liquid at around room temperature.
  • the concentration of the ionic substance in the electrolytic solution is, for example, 0.5 mol/L or more and 2.0 mol/L.
  • a solvent with a high boiling point is preferable.
  • lactones such as ⁇ -butyrolactone
  • carbonates such as propylene carbonate
  • polyhydric alcohols such as ethylene glycol and propylene glycol
  • cyclic sulfones such as sulfolane
  • N-methylacetamide N,N-dimethylformamide
  • N- Amides such as methyl-2-pyrrolidone
  • esters such as methyl acetate
  • ethers such as 1,4-dioxane
  • ketones such as methyl ethyl ketone
  • formaldehyde formaldehyde
  • Ionic substances include, for example, organic salts.
  • An organic salt is a salt in which at least one of the anion and cation contains an organic substance.
  • Examples of organic salts whose cations include organic substances include quaternary ammonium salts.
  • Organic salts in which the anion (or both ions) contain an organic substance include, for example, trimethylamine maleate, triethylamine borodisalicylate, ethyldimethylamine phthalate, mono-1,2,3,4-tetramethylimidazolinium phthalate, phthalate acid mono 1,3-dimethyl-2-ethylimidazolinium;
  • the anion preferably contains an anion of a fluorine-containing acid from the viewpoint of improving withstand voltage characteristics.
  • Anions of fluorine-containing acids include, for example, BF 4 - and/or PF 6 - .
  • the organic salt preferably contains, for example, a tetraalkylammonium cation and a fluorine-containing acid anion. Specific examples include diethyldimethylammonium tetrafluoroborate (DEDMABF 4 ), triethylmethylammonium tetrafluoroborate (TEMABF 4 ), and the like.
  • a separator may be placed between the pair of electrodes.
  • the separator has ion permeability and has a role of physically separating a pair of electrodes to prevent a short circuit.
  • a nonwoven fabric containing cellulose as a main component, a glass fiber mat, or a microporous film of polyolefin such as polyethylene is used.
  • FIG. 1 is a partially cutaway perspective view of an electrochemical device.
  • An electrochemical device 10 in FIG. 1 is an electric double layer capacitor and includes a wound capacitor element 1.
  • the capacitor element 1 is configured by winding a sheet-like first electrode 2 and a sheet-like second electrode 3 with a separator 4 interposed therebetween.
  • the first electrode 2 and the second electrode 3 each have a first current collector and a second current collector made of metal, and a first active layer and a second active layer supported on the surface thereof, and adsorb ions. And the capacity is expressed by desorption.
  • At least one of the first active layer and the second active layer is the active layer described above.
  • a first lead wire 5a and a second lead wire 5b are connected to the first electrode 2 and the second electrode 3, respectively, as lead members.
  • Capacitor element 1 is housed in a cylindrical exterior case 6 together with an electrolytic solution (not shown).
  • the material of the exterior case 6 may be any metal such as aluminum, stainless steel, copper, iron, brass, or the like.
  • the opening of the exterior case 6 is sealed with a sealing member 7 .
  • the lead wires 5 a and 5 b are led out to the outside so as to pass through the sealing member 7 .
  • a rubber material such as butyl rubber, for example, is used for the sealing member 7 .
  • FIG. 1 shows an example of a wound capacitor
  • the present disclosure is not limited to the above example.
  • the present disclosure can also be applied to capacitors of other structures, such as stacked or coin-shaped capacitors.
  • Electrochemical Device DA1 As an electrochemical device, a wound electric double layer capacitor (device DA1) with a rated voltage of 2.7 V was produced. A specific method for manufacturing the device DA1 will be described below.
  • a slurry was prepared by dispersing 100 parts by mass of porous carbon particles (active material), a binder, and 6.66 parts by mass of acetylene black (conductive agent) in water. Porous carbon particles used had average particle diameters and specific surface areas shown in Table 1 below.
  • the binder shown in Table 1 was used as the binder. The porous carbon particles and the binder were mixed so as to have the parts by mass shown in Table 1. However, the total mass reduction amount of the binder in Table 1 is a measured value obtained by analyzing the fabricated capacitor.
  • the resulting slurry was applied to an aluminum foil (thickness: 30 ⁇ m, current collector) to form a coating film.
  • the coating film was dried with hot air at 110° C. and rolled to form an active layer (thickness: 40 ⁇ m). An electrode was thus obtained.
  • An electrolytic solution was prepared by dissolving diethyldimethylammonium tetrafluoroborate (DEDMABF 4 ) in ⁇ -butyrolactone (GBL).
  • the concentration of DEDMABF 4 in the electrolytic solution was 1.0 mol/L.
  • Electrode DA1 (Preparation of electrochemical device DA1) Two electrodes were prepared as described above, and lead wires were connected to each of them. Next, a capacitor element was formed by winding the two electrodes with a separator (cellulose non-woven fabric) interposed therebetween. The capacitor element was housed in a predetermined exterior case together with an electrolytic solution, and sealed with a sealing member. Thus, an electric double layer capacitor was assembled. The obtained capacitor was subjected to aging treatment at 60° C. for 16 hours while applying a rated voltage. Thus, a device DA1 (electric double layer capacitor) was obtained.
  • DA2 to DA8 and DB1 to DB7 are similar methods and conditions.
  • the average particle size of the porous particles was changed by pulverizing the porous particles.
  • Roughened aluminum foil was used as the aluminum foil for the electrodes of devices DA7, DA8, and DB7.
  • the capacitance of the aluminum foil was measured by the method described above.
  • Devices DA9 and DA10 are devices for evaluating the effect of the above ratio B/A.
  • Table 1 shows the ratio B/A in the active layer of each electrode. The ratio B/A of devices other than devices DA9 and DA10 was not evaluated.
  • the electrochemical devices DA1 to DA10 are electrochemical devices according to the present disclosure.
  • Electrochemical devices DB1 to DB7 are comparative devices. These electrochemical devices, electrodes used therein, and porous carbon particles used therein were evaluated as follows.
  • the pore distribution of the porous carbon particles was measured by the gas adsorption method using nitrogen gas, as described above.
  • the sample of porous carbon particles was subjected to pretreatment by heat evacuation (for example, 50 mTorr or less at 250° C.) before the measurement.
  • the BJH method Barrett-Joyner-Halenda method
  • the BJH method uses the Harkins & Jura formula.
  • the cumulative volumes A and B above were determined using the cumulative pore volume distribution obtained by the BJH method.
  • the mass of binder in the electrode was determined by thermogravimetric analysis (TGA). Specifically, first, the active layer of the electrode was peeled off and dried at 130° C. for 2 hours to obtain a sample. The sample was weighed and then analyzed by thermogravimetric analysis. From this, the amount of mass reduction due to the binder in the active layer was obtained. Thermogravimetric analysis was performed under the following conditions. Analyzer: NEXTA STA300 (Hitachi High-Tech Co., Ltd.) ⁇ Temperature, heating rate, atmosphere> 25°C-650°C, 10°C/min, N2 gas flow 650-900°C, 10°C/min, air 900°C, hold for 5 min, air
  • the type of binder in the electrode was identified by pyrolysis gas chromatography/mass spectrometry (pyrolysis GC/MS) as described above.
  • Table 1 shows part of the manufacturing conditions of the electrochemical device and the above evaluation results.
  • the capacity density is the capacity (F) per cm 3 of the active layer, which is the initial capacity density before the float test.
  • the resistance change slope obtained by the above formula (4) was 1.2 at DA9 and 1.5 at DA10. That is, by setting the ratio B/A to 1 or more, the float characteristics became better. Although the reason for this is not clear, it can be considered as follows. When charging and discharging are performed, decomposition products of the electrolytic solution and the like are generated. These decomposed products tend to clog micropores and the like. Therefore, when the proportion of micropores is high (the value of the ratio B/A is low), the proportion of pores that are blocked increases, and the float property tends to deteriorate. As shown in the above examples, by setting the ratio B/A to 1 or more, the float characteristics can be enhanced.
  • the capacity density (especially capacity density at low temperatures) can be greatly increased by reducing the particle size of the porous carbon particles.
  • the particle size of the porous carbon particles is reduced, the adhesion strength of the active layer is lowered, so even if a normal binder (for example, only one type of binder) is used, the adhesion strength of the active layer cannot be maintained.
  • the adhesion strength of the active layer can be improved by using carboxymethyl cellulose and rubber (especially styrene-butadiene rubber) as the binder and limiting the amount of the binder to a predetermined range. did it.
  • the electrochemical device according to the present disclosure was able to achieve both high capacity and high reliability.
  • the present disclosure can be used for electrodes for electrochemical devices and electrochemical devices using the same.

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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

L'invention concerne une électrode pour dispositifs électrochimiques qui comprend une couche active, la couche active contenant des particules de carbone poreuses et un liant. Les particules de carbone poreuses ont un diamètre moyen de particule de 0,5 à 1,0 µm. Le liant contient : au moins un type de carboxyméthylcellulose choisi parmi la carboxyméthylcellulose et des sels de carboxyméthylcellulose ; et, du caoutchouc. La quantité d'appauvrissement en masse sur la base de la carboxyméthylcellulose et du caoutchouc lors de l'analyse thermogravimétrique de la couche active est de 8,2-21,3 %, inclus, de la masse de la couche active.
PCT/JP2022/019065 2021-06-30 2022-04-27 Électrode pour dispositif électrochimique, et dispositif électrochimique Ceased WO2023276436A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025191891A1 (fr) * 2024-03-15 2025-09-18 パナソニックＩｐマネジメント株式会社 Condensateur

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006068291A1 (fr) * 2004-12-21 2006-06-29 Teijin Limited Condensateur electrique double couche
JP2010245423A (ja) * 2009-04-09 2010-10-28 Teijin Ltd 電気二重層キャパシタ用導電助剤および電気二重層キャパシタ
JP2012204748A (ja) * 2011-03-28 2012-10-22 Jm Energy Corp リチウムイオンキャパシタ
JP2018014466A (ja) * 2016-07-22 2018-01-25 株式会社巴川製紙所 分極性電極および電気二重層キャパシタ
JP2018092978A (ja) * 2016-11-30 2018-06-14 マツダ株式会社 電気二重層キャパシタ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006068291A1 (fr) * 2004-12-21 2006-06-29 Teijin Limited Condensateur electrique double couche
JP2010245423A (ja) * 2009-04-09 2010-10-28 Teijin Ltd 電気二重層キャパシタ用導電助剤および電気二重層キャパシタ
JP2012204748A (ja) * 2011-03-28 2012-10-22 Jm Energy Corp リチウムイオンキャパシタ
JP2018014466A (ja) * 2016-07-22 2018-01-25 株式会社巴川製紙所 分極性電極および電気二重層キャパシタ
JP2018092978A (ja) * 2016-11-30 2018-06-14 マツダ株式会社 電気二重層キャパシタ

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025191891A1 (fr) * 2024-03-15 2025-09-18 パナソニックＩｐマネジメント株式会社 Condensateur

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