WO2020158797A1 - Électrode, son procédé de production et batterie - Google Patents

Électrode, son procédé de production et batterie Download PDF

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Publication number
WO2020158797A1
WO2020158797A1 PCT/JP2020/003162 JP2020003162W WO2020158797A1 WO 2020158797 A1 WO2020158797 A1 WO 2020158797A1 JP 2020003162 W JP2020003162 W JP 2020003162W WO 2020158797 A1 WO2020158797 A1 WO 2020158797A1
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Prior art keywords
electrode
carbon
battery
positive electrode
redox flow
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PCT/JP2020/003162
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English (en)
Japanese (ja)
Inventor
義史 横山
丈智 西方
ティンティン シュウ
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昭和電工株式会社
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    • 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
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • 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
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/96—Carbon-based electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to an electrode, a method for manufacturing the electrode, and a battery including the electrode.
  • a redox flow battery supplies and circulates a positive electrode electrolytic solution and a negative electrode electrolytic solution to and from a battery cell having a positive electrode, a negative electrode, and a diaphragm interposed between both electrodes, and a power converter (for example, an AC/DC converter or the like). ) Is used to charge and discharge.
  • a power converter for example, an AC/DC converter or the like.
  • the electrolytic solution an aqueous solution containing a metal ion (active material) whose valence changes by redox is usually used.
  • a vanadium redox flow battery using vanadium (V) as an active material of a positive electrode and a negative electrode is well known.
  • Carbon materials such as carbon nanotubes and carbon fibers are used as the material of the electrodes used in such a redox flow battery.
  • Patent Document 1 describes the use of vapor grown carbon fiber as an electrode material of a redox flow battery.
  • Patent Document 2 a carbon fiber felt having voids inside the felt is used as a material of the electrode which has a small pressure loss when an electrolytic solution is passed through the electrode and has good conductivity in the thickness direction. Is described.
  • the redox flow battery described in Patent Documents 1 and 2 is a redox flow battery using a vanadium-based electrolyte solution, which has a low cell resistivity and a small pressure loss when the electrolyte solution is passed through the electrodes. It was done.
  • electrolytes other than vanadium-based electrolytes that contain ions with a high oxidizing power such as manganese-titanium-based electrolytes.
  • an electrode for a redox flow battery which is less likely to cause deterioration of the electrode due to oxidation, more specifically, increase in cell resistivity and breakage.
  • An object of the present invention is to provide an electrode, a manufacturing method thereof, and a battery, which are less likely to be deteriorated by oxidation.
  • the present inventors have found that the carbon electrode material constituting the electrode, appearing in the Raman spectrum measured by Raman spectroscopy, the peak intensity of D-band (I D) and the peak intensity of G-band peak intensity ratio (I G) ( By including a carbon material having a small I D /I G ratio), it was found that the increase in cell resistivity due to oxidation is unlikely to occur even when the battery is repeatedly used, and the present invention has been completed. More specifically, the present invention provides the following.
  • the present invention is an electrode having a carbon electrode material, wherein the carbon electrode material has a G band peak intensity of a D band peak intensity (I D ) that appears in a Raman spectrum measured by Raman spectroscopy.
  • I D D band peak intensity
  • I G peak intensity ratio
  • the content of oxygen element is an electrode containing a carbon material is less than 0.50 wt%.
  • the present invention is the electrode according to (1), wherein the carbon electrode material contains 50% by mass or more of the carbon material.
  • the present invention is the electrode according to (1) or (2), wherein the carbon material includes carbon fiber.
  • the present invention is the electrode according to (3), wherein the carbon fiber has an average fiber diameter of 1 ⁇ m or more.
  • the present invention also provides the electrode according to (3) or (4), wherein the carbon electrode material is composed of a sheet material of carbon felt or carbon paper formed using the carbon fiber.
  • the present invention is the electrode according to any one of (1) to (5), wherein the electrode is used as a positive electrode of a redox flow battery.
  • the present invention is a battery including a positive electrode and a negative electrode, wherein the positive electrode is the electrode according to any one of (1) to (6).
  • the battery is a redox flow battery, and further comprises a positive electrode electrolytic solution supplied to the positive electrode and a negative electrode electrolytic solution supplied to the negative electrode, wherein the positive electrode electrolytic solution is:
  • the battery according to (7) which contains one or more ions selected from manganese ions, cerium ions, and chlorine ions.
  • the present invention is the method for manufacturing an electrode according to any one of (1) to (6), wherein the molded body containing a carbon material is treated in an inert gas atmosphere at 2300° C. or higher and 3500° C. or lower.
  • a method for manufacturing an electrode which includes a high-temperature firing step of firing to obtain a carbon electrode material.
  • a low temperature firing step of firing the molded body in an atmosphere containing oxygen gas at 700° C. or lower is performed before performing the high temperature firing step. It is a manufacturing method.
  • the present invention it is possible to obtain a battery electrode that is less likely to be deteriorated by oxidation, a manufacturing method thereof, and a battery.
  • FIG. 5 is an SEM (scanning electron microscope) image of the surface of carbon fiber that constitutes the same carbon paper as in Example 1.
  • FIG. 2A is a SEM image of the carbon fiber surface before the low temperature firing step
  • FIG. 2B is a SEM image of the carbon fiber surface after the low temperature firing step and before the high temperature firing step. It is a statue.
  • the electrode of the present embodiment is an electrode having a carbon electrode material, and the carbon electrode material has a G-band peak intensity (I D ) of the D-band peak intensity ( ID ) that appears in a Raman spectrum measured by Raman spectroscopy.
  • I G peak intensity ratio) (I D / I G ratio) is 0.50 or less, and the content of oxygen element comprises a carbon material is less than 0.50 wt%.
  • the electrode (hereinafter, also referred to as “battery electrode”) according to the present embodiment mainly includes a carbon electrode material containing a carbon material.
  • the carbon material contained in the carbon electrode material (hereinafter sometimes referred to as “carbon material A”) is the G band of the peak intensity ( ID ) of the D band that appears in the Raman spectrum measured by Raman spectroscopy.
  • peak intensity peak intensity ratio (I G) (I D / I G ratio) is 0.50 or less, and the content of oxygen element is less than 0.50 wt%.
  • the carbon electrode material containing the carbon material A is mainly used, and the I D /I G ratio of the carbon material A is reduced so that the electrode is placed in an environment with high oxidizing power.
  • the I D /I G ratio of the carbon material A is reduced so that the electrode is placed in an environment with high oxidizing power.
  • Carbon material A The carbon material A contained in the carbon electrode material, appearing in the Raman spectrum measured by Raman spectroscopy, the peak intensity of D-band (I D), the peak intensity ratio to the peak intensity of G-band (I G) (I D / I G ratio) is 0.50 or less.
  • the ratio ( ID / IG ratio) of the peak intensity ( ID ) of the D band appearing due to the disorder and the defect of the carbon material structure to the peak intensity ( IG ) of the G band derived from the graphite structure of the carbon material. ) Is set to 0.50 or less, the electrode is less likely to be oxidized by oxygen (O 2 ) or an electrolytic solution containing ions having high oxidizing power.
  • the I D /I G ratio of the carbon material A is preferably 0.45 or less, and more preferably 0.40 or less.
  • the content of oxygen element in this carbon material A is 0.50 mass% or less.
  • the oxygen element in the carbon material A is preferably 0.40 mass% or less, and more preferably 0.30 mass% or less.
  • Examples of the carbon material A include carbon fibers, graphene, carbon black, etc., which have an I D /I G ratio of 0.50 or less and an oxygen element content of 0.50 mass% or less. One of these materials may be used, or two or more of them may be used. When using two or more kinds of materials as the carbon material A, D peak intensity of band (I D), the peak intensity ratio to the peak intensity of G-band (I G) (I D / I G ratio), various carbon materials The weighted average value obtained from the sum of the values obtained by multiplying the I D /I G ratio by the mass ratio.
  • the carbon material A preferably contains carbon fibers.
  • examples of the carbon fiber include a fibrous (including tubular) carbon material having an average fiber diameter of 10 nm or more.
  • the upper limit of the average fiber diameter of the carbon fibers is preferably set from the viewpoint of ease of processing into a carbon electrode material, and can be set to, for example, 200 ⁇ m or less.
  • a plurality of types of carbon fibers having different average fiber diameters and average fiber lengths may be included as the carbon material A.
  • the carbon fibers include those having an average fiber diameter of 1 ⁇ m or more and those having an average fiber diameter of less than 1 ⁇ m (for example, carbon nanofibers and carbon nanotubes).
  • the average fiber diameter of the carbon fibers is preferably in the range of 1 ⁇ m to 200 ⁇ m, more preferably 2 ⁇ m to 100 ⁇ m, and further preferably 5 ⁇ m to 30 ⁇ m.
  • the average fiber length of the carbon fibers is preferably 0.01 mm to 20 mm, more preferably 0.05 mm to 10 mm, still more preferably 0.1 mm to 8 mm.
  • the average fiber diameter of the carbon nanofibers or carbon nanotubes is preferably 1 nm to 300 nm, more preferably 10 nm to 200 nm, More preferably, it is in the range of 15 nm to 150 nm.
  • the average fiber length of the carbon nanotubes is preferably in the range of 0.1 ⁇ m to 30 ⁇ m, more preferably 0.5 ⁇ m to 25 ⁇ m, still more preferably 0.5 ⁇ m to 20 ⁇ m.
  • the average fiber diameter and the average fiber length of the carbon fibers are obtained by randomly measuring the diameters (fiber diameters) of 100 or more carbon fibers using a transmission electron microscope (TEM), and calculating the arithmetic average value thereof. You can ask.
  • TEM transmission electron microscope
  • Carbon fiber can be molded into carbon felt when the fiber length is relatively long, and can be molded into carbon paper when the fiber length is relatively short. At this time, as the average fiber length of the carbon fibers, it is preferable to adopt a dimension suitable for each shape.
  • the carbon electrode material is configured using the above-mentioned carbon material A, for example, carbon fiber. Since the electrode according to the present embodiment includes such a carbon electrode material, the oxidation resistance of the electrode is improved, so that the deterioration due to the oxidation of the electrode can be made difficult to occur.
  • the carbon electrode material in addition to the carbon material A described above, the carbon material B I D / I G ratio of 0.50 than, the I D / I G ratio is 0.50 or less, and oxygen element
  • the carbon material C having a content of 0.50% by mass or more, or a conductive polymer may be further included.
  • the content of the above carbon material A in the carbon electrode material is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more with respect to the mass of the carbon electrode material.
  • the shape of the carbon electrode material can be appropriately set according to the type and the form of the battery in which the electrode is used. Among them, it is preferable to have a sheet shape from the viewpoint of improving productivity and handleability.
  • the thickness of the carbon electrode material in the dry state can be appropriately set according to the type of battery in which the electrode is used, etc., and is preferably 0.1 mm to 1.0 mm, more preferably 0 mm.
  • the range is 0.2 mm to 0.9 mm, more preferably 0.3 mm to 0.7 mm.
  • the electrode according to the present embodiment is mainly composed of a carbon electrode material containing the above-mentioned carbon material A and can be used as at least a positive electrode in various batteries.
  • the electrode according to the present embodiment has high durability because it is unlikely to be deteriorated by oxidation caused by oxygen (O 2 ) or ions having high oxidizing power in the electrolytic solution. Therefore, the electrode according to the present embodiment can be suitably used as an electrode of a redox flow battery, in particular, as a positive electrode of a redox flow battery using an electrolytic solution containing highly oxidizing ions as a positive electrode electrolytic solution. The increase in cell resistivity due to repeated use of the battery can be suppressed.
  • the battery according to the present embodiment includes at least a positive electrode and a negative electrode, and uses the above-mentioned electrode as at least the positive electrode. As a result, deterioration of the electrode due to oxidation is less likely to occur, so that durability of the electrode can be improved.
  • FIG. 1 is a schematic configuration diagram showing a configuration of a redox flow battery as an example of the configuration of the battery according to the present embodiment.
  • a manganese compound is used as the active material of the positive electrode side electrolytic solution (positive electrode electrolytic solution) and a titanium compound is used as the negative electrode side electrolytic solution (negative electrode electrolytic solution) is shown as an example.
  • the redox flow battery 1 includes a positive electrode 111 and a negative electrode 121, and includes a positive electrode cell 11 including the positive electrode 111, a negative electrode cell 12 including the negative electrode 121, a positive electrode 111, and
  • the battery cell 10 mainly has a battery cell 10 that is interposed between the negative electrodes 121 to separate the two cells and has an ion exchange membrane 13 that allows predetermined ions to pass therethrough.
  • the redox flow battery 1 according to the present embodiment includes a positive electrode electrolytic solution supplied to the positive electrode 111 and a negative electrode electrolytic solution supplied to the negative electrode 121.
  • the redox flow battery 1 is used alone or in a form called a battery cell stack in which a plurality of battery cells 10 are stacked with the battery cell 10 as a minimum unit, and the battery cell 10 is charged by circulating an electrolytic solution. Discharge.
  • the above-mentioned electrode is used as at least the positive electrode 111.
  • the positive electrode electrolyte contains ions having a high oxidizing power
  • the positive electrode 111 is less likely to be oxidized, and therefore, even if the redox flow battery 1 is repeatedly used, the deterioration of the positive electrode 111 can be less likely to occur. it can.
  • one of the two surfaces of the redox flow battery electrode may be held by an electrode plate (not shown).
  • the redox flow battery electrode should be arranged between the ion exchange membrane 13 and the electrode plate. Is preferred.
  • the redox flow battery electrode is provided so that one of the two surfaces, which does not face the electrode plate, faces the ion exchange membrane 13.
  • the positive electrode electrolyte and the negative electrode electrolyte of the redox flow battery 1 each contain an active material, and the types thereof are not particularly limited.
  • the ions generated from the active material contained in the positive electrode electrolyte include ions having high oxidizing power, for example, one or more ions selected from manganese ion, cerium ion and chlorine ion. It may be.
  • the ions generated from the active material on the negative electrode side included in the negative electrode electrolyte those that are combined with the ions on the positive electrode side described above are used.
  • the positive electrode electrolytic solution contains a manganese compound as an active material
  • the negative electrode electrolytic solution can contain a titanium compound as an active material.
  • a known cation exchange membrane can be used as the ion exchange membrane 13 used in the redox flow battery 1.
  • a perfluorocarbon polymer having a sulfonic acid group a hydrocarbon-based polymer compound having a sulfonic acid group, a polymer compound doped with an inorganic acid such as phosphoric acid, a part of which is a proton-conductive functional group.
  • examples include organic/inorganic hybrid polymers substituted with, and a proton conductor obtained by impregnating a polymer matrix with a phosphoric acid solution or a sulfuric acid solution.
  • perfluorocarbon polymers having a sulfonic acid group are preferable, and Nafion (registered trademark) is more preferable.
  • the redox flow battery 1 includes a positive electrode electrolytic solution tank 112 that stores a positive electrode electrolytic solution that is circulated and supplied to the positive electrode cell 11, a positive electrode outward pipe 115 that sends the positive electrode electrolytic solution from the positive electrode electrolytic solution tank 112 to the positive electrode cell 11, and a positive electrode electrolytic solution. And a positive electrode return pipe 114 for returning from the positive electrode cell 11 to the positive electrode electrolyte tank 112. Of these, a pump 113 for circulating the positive electrode electrolytic solution is arranged in the positive electrode outward pipe 114.
  • the redox flow battery 1 includes a negative electrode electrolyte tank 122 that stores a negative electrode electrolyte solution that is circulated and supplied to the negative electrode cell 12, and a negative electrode outward pipe 124 that sends the negative electrode electrolyte solution from the negative electrode electrolyte solution tank 122 to the negative electrode cell 12.
  • a negative electrode return pipe 125 for returning the negative electrode electrolytic solution from the negative electrode cell 12 to the negative electrode electrolytic solution tank 122 is provided.
  • a pump 123 for circulating the negative electrode electrolyte is arranged in the negative electrode outward pipe 124.
  • the electrolytic solution in the positive electrode electrolytic solution tank 112 is sent to the battery cell 10 (more strictly, the positive electrode cell 11) through the positive electrode outward pipe 114 by operating the pump 113. ..
  • the positive electrode electrolytic solution sent to the battery cell 10 is discharged upward through the inside of the battery cell 10 and returned to the positive electrode electrolytic solution tank 112 through the positive electrode return pipe 115 and circulates in the direction of arrow A in the figure. ..
  • the electrolytic solution in the negative electrode electrolytic solution tank 122 is sent to the battery cell 10 (more strictly, the negative electrode cell 12) through the negative electrode outward pipe 124 by operating the pump 123.
  • the electrolytic solution sent to the battery cell 10 is discharged upward through the inside of the battery cell 10 and returned to the negative electrode electrolytic solution tank 112 through the negative electrode return pipe 125 and circulates in the direction of arrow B in the figure.
  • the redox reaction of the active material contained in the electrolytic solution is carried out in the battery cell 10, and it becomes possible to store or take out the electric power. That is, it becomes possible to charge the electric power supplied from the power supply 31 such as a power plant via the AC/DC converter 2. Further, it becomes possible to discharge the charged power to the load 32 via the AC/DC converter 2.
  • the battery cell 10 of the redox flow battery 1 is described as a single cell, but may be formed in a form called a cell stack in which a plurality of single cells are stacked (not shown). ).
  • the electrode manufacturing method according to the present embodiment is performed by firing a molded body containing a carbon material (carbon material molded body) such as carbon felt or carbon paper in an inert gas atmosphere of 2300° C. or higher and 3500° C. or lower. It has a high temperature firing step of obtaining an electrode material. If necessary, a low temperature firing step may be performed on the carbon material compact before the high temperature firing step.
  • a carbon material carbon material molded body
  • carbon felt or carbon paper containing carbon fiber can be used, and carbon felt made of carbon fiber or carbon paper is preferable.
  • a carbon material molded body may be produced from carbon fiber by a known means, or commercially available carbon felt or carbon paper may be processed into a predetermined size and used as a carbon material molded body. ..
  • Low temperature firing process In the present embodiment, it is preferable to perform a low temperature firing step of firing the carbon material molded body in an atmosphere containing oxygen gas at 700° C. or lower before performing a high temperature firing step described later.
  • the surface area of the carbon material forming the carbon material molded body is increased by performing the low temperature firing step on the carbon material molded body in an atmosphere containing oxygen gas.
  • an atmosphere containing oxygen gas can be used as an atmosphere for performing the low temperature firing step.
  • the firing temperature in the low-temperature firing process shall be 700°C or lower.
  • the firing temperature in the low temperature firing step is preferably 600° C. or lower, and more preferably 500° C. or lower.
  • the lower limit of the firing temperature may be, for example, 300° C. or higher, or 400° C. or higher.
  • the firing time in the low temperature firing process is set according to the firing temperature and the oxygen gas concentration in the atmosphere. More specifically, it is preferably 0.5 hours to 10 hours, more preferably 1 hour to 5 hours, and further preferably 2 hours to 4 hours.
  • the temperature rising rate up to the predetermined firing temperature is 0.5° C./minute or more from the viewpoint of increasing the productivity in the low temperature firing step and reducing the cost.
  • the heating rate is preferably 100° C./minute or less, more preferably 1° C./minute or more and 25° C./minute or less.
  • the cooling after the elapse of a predetermined firing time is preferably performed at a cooling rate of 0.5° C./minute or more and 100° C./minute or less, and is preferably performed at a cooling rate of 1° C./minute or more and 25° C./minute or less. Is more preferable.
  • the carbon material molded body fired in the low temperature firing step is fired in an inert gas atmosphere of 2300° C. or higher and 3500° C. or lower as necessary to obtain a carbon electrode material.
  • the proportion of carbon in the carbon material occupied by the graphite structure increases, and the proportion of other phases and defects or edges in the graphite structure and other phases are increased. The ratio of will decrease.
  • the oxygen atoms attached to the carbon material are removed, the content of oxygen element contained in the carbon material is reduced. With these, when the obtained electrode is used in a battery, it is possible to obtain a low cell resistivity in the initial state and to prevent deterioration of the electrode due to oxidation or the like.
  • Examples of the inert gas that constitutes the atmosphere in which the high temperature firing step is performed include noble gases such as argon (Ar) gas and nitrogen (N 2 ) gas.
  • the temperature (firing temperature) for firing in the high-temperature firing process should be 2300°C or higher and 3500°C or lower.
  • the firing temperature in the high temperature firing step is preferably 2400° C. or higher, and more preferably 2500° C. or higher.
  • the upper limit of the firing temperature is preferably 3300°C or lower, more preferably 3100°C or lower.
  • the time for performing the firing in the high temperature firing step can be appropriately established within the range where the above-mentioned I D /I G ratio is 0.5 or less.
  • the firing time in the high temperature firing step may be, for example, 15 minutes to 4 hours.
  • the rate of temperature increase until reaching a predetermined firing temperature is 0.5° C./minute or more and 100° C./minute or more from the viewpoint of making deterioration of electrode performance less likely to occur.
  • the heating rate is preferably the following, and more preferably 1° C./minute or more and 25° C./minute or less.
  • the cooling after the elapse of a predetermined firing time is preferably performed at a cooling rate of 0.5° C./minute or more and 100° C./minute or less, and is preferably performed at a cooling rate of 1° C./minute or more and 25° C./minute or less. Is more preferable.
  • the electrode manufacturing method includes a high temperature firing step of firing a carbon material in an inert gas atmosphere of 2300° C. or higher and 3500° C. or lower, and a carbon electrode formed by molding the carbon material fired in the high temperature firing step. Forming step of obtaining a material. If necessary, the low temperature firing step may be performed on the carbon material before the high temperature firing step.
  • the low temperature firing step and the high temperature firing step can be performed in the same manner as in the first embodiment, except that an unformed carbon material is used instead of the carbon material molded body.
  • the forming step is a step of forming the carbon material fired in the high temperature firing step to obtain a carbon electrode material.
  • a known method for obtaining a carbon material molded body such as carbon felt or carbon paper from carbon fiber can be used.
  • the carbon material can be formed into a sheet using this dispersion liquid.
  • the dispersion medium for dispersing the carbon material is not particularly limited, and for example, water can be used.
  • a dispersant When dispersing the carbon material in the dispersion medium, it is preferable to add a dispersant to the dispersion medium, which can facilitate the uniform dispersion of the carbon material.
  • a dispersant a known dispersant can be used, and for example, a water-soluble conductive polymer can be used.
  • the method for dispersing the carbon material to prepare the dispersion liquid is not particularly limited, and examples thereof include a method using ultrasonic waves, a ball mill, and a magnetic stirrer.
  • a method of forming a carbon material into a sheet from the obtained dispersion liquid for example, a method of drying the dispersion medium after applying the dispersion liquid to a substrate, or filtering the dispersion liquid to remove the dispersion medium. Any method can be used.
  • an electrode having a carbon electrode material containing a carbon material having an I D /I G ratio by Raman spectroscopy of 0.50 or less and an oxygen element content of 0.50 mass% or less can be obtained.
  • the carbon material is subjected to the low temperature firing step and the high temperature firing step, and in the molding step, the carbon material after firing is molded to obtain the carbon electrode material.
  • You may perform a shaping
  • the electrode thus obtained can be incorporated into a battery by a conventional method, for example, the redox flow battery 1 shown in FIG.
  • this electrode is provided on one side of the ion exchange membrane 13, and the negative electrode 121 is separately provided on the other side of the ion exchange membrane 13.
  • Example 1 Preparation of carbon material molded body
  • carbon paper of size (length 100 mm, width 100 mm, thickness 0.19 mm) (manufactured by SGL Carbon Co., model number GDL-39AA) is used. I was there.
  • This carbon paper is made of carbon fiber which is a carbon material, and the average fiber diameter of the carbon fibers constituting the carbon paper is 1 ⁇ m.
  • Low temperature firing step for carbon material molded body As a low temperature firing step, the carbon paper was fired at a firing temperature of 480° C. in air for a firing time of 3 hours (3 h). Here, the temperature was raised to the firing temperature at a rate of 10° C./min, and after firing, it was cooled to room temperature at a cooling rate of 10° C./min.
  • High temperature firing step for carbon material molded body As a high temperature firing step, the carbon paper after low temperature firing is fired at a firing temperature of 3000° C. in an argon (Ar) gas for a firing time of 1 hour (1 h). A carbon electrode material was produced. Here, the temperature was raised to the firing temperature at a heating rate of 10° C./min, and after firing, the temperature was cooled to room temperature at a cooling rate of 10° C./min to obtain a carbon electrode material.
  • Ar argon
  • the carbon electrode material has the following 4. 4. The number of sheets necessary for evaluating the I D /I G ratio and the content of oxygen element, and 5. Then, the total number of sheets required for use in the positive electrode of the battery was prepared. In addition, regarding the carbon material molded body after the above-mentioned low temperature firing step, the following 5. Then, the number of sheets required for use as the negative electrode of the battery was prepared.
  • I D /I G ratio D band peak appearing in Raman spectrum measured by Raman spectroscopy of the obtained carbon electrode material
  • the intensity (I D ) and the peak intensity (I G ) of the G band are determined, and the peak intensity ratio (I D /is the ratio of the peak intensity (I D ) of the D band to the peak intensity (I G ) of the G band.
  • IG ratio was determined.
  • a laser Raman spectrophotometer manufactured by JASCO Corporation, model number: NRS-5100 was used as the spectrophotometer, and the excitation wavelength was 532.36 nm, the laser intensity was 1.6 mW, the incident slit width was 50 ⁇ m, and the exposure time was 15 seconds.
  • Raman spectroscopic spectra were measured twice under a condition of 600 diffraction gratings/mm, and the peak intensity ( ID ) of the D band near 1360 cm -1 and the peak intensity of the G band near 1580 cm -1. The ratio to ( IG ) was determined.
  • the positive electrode electrolytic solution and the negative electrode electrolytic solution are obtained by dissolving manganese sulfate (MnSO 4 ) and titanium oxide sulfate (TiOSO 4 ) in an aqueous sulfuric acid solution, respectively.
  • the manganese ion concentration is 1M
  • the titanium ion concentration is 1M
  • the sulfuric acid is 1M.
  • An electrolytic solution having an ion concentration of 5M was used. 50 mL of this electrolytic solution was introduced into each of the positive electrode side and the negative electrode side of the redox flow battery to form a single cell of the redox flow battery.
  • the initial resistivity of the redox flow battery was the cell resistivity obtained after repeating the charge/discharge cycle 5 times.
  • the charge average voltage and the discharge average voltage were obtained, and the values were obtained based on the following calculation formula.
  • Cell resistivity [ ⁇ cm 2 ] (charge average voltage [V] ⁇ discharge average voltage [V]) ⁇ electrode area [cm 2 ] ⁇ (2 ⁇ charge current [A])
  • Example 2 In "3. High-temperature firing step for molded carbon material", a carbon electrode material was produced in the same manner as in Example 1 except that the firing temperature was 2500°C, and a single cell of a redox flow battery was constructed. The obtained carbon electrode material was similarly evaluated for the I D /I G ratio and the oxygen element content. Further, regarding the obtained redox flow battery, similarly, the cell resistivity in the initial state, the cell resistivity after repeated use, and the resistivity deterioration rate were confirmed.
  • Example 3 A carbon electrode material was produced in the same manner as in Example 2 except that the carbon paper was not subjected to the "2. Low temperature firing step for the carbon material molded body", but was subjected to the high temperature firing step, and also the redox flow battery. The single cell of The obtained carbon electrode material was similarly evaluated for the I D /I G ratio and the oxygen element content. Further, regarding the obtained redox flow battery, similarly, the cell resistivity in the initial state, the cell resistivity after repeated use, and the resistivity deterioration rate were confirmed.
  • Example 1 The carbon paper was used as it is as a carbon electrode material without performing “2. Low temperature firing step for carbon material compact” and “3. High temperature firing step for carbon material compact,” as in Example 1. A single cell of a redox flow battery was constructed. Similarly, the unburned carbon paper used as the carbon electrode material was evaluated for the I D /I G ratio and the oxygen element content. Further, regarding the obtained redox flow battery, similarly, the cell resistivity in the initial state, the cell resistivity after repeated use, and the resistivity deterioration rate were confirmed.
  • Example 3 In "3. High-temperature firing step for carbon material molded body", a carbon electrode material was produced in the same manner as in Example 1 except that the firing temperature was set to 2000°C, and a single cell of a redox flow battery was constructed. The obtained carbon electrode material was similarly evaluated for the I D /I G ratio and the oxygen element content. Further, regarding the obtained redox flow battery, similarly, the cell resistivity in the initial state, the cell resistivity after repeated use, and the resistivity deterioration rate were confirmed.
  • Table 1 shows various conditions in Examples 1 to 3 and Comparative Examples 1 to 3, I D /I G ratio, oxygen element content, cell resistivity in the initial state, cell resistivity after repeated use, and resistance. The rate of deterioration is shown below.
  • the carbon electrode material has an I D /I G ratio of 0.50 or less and an oxygen element content of 0.50 mass% or less, so that I D / compared to the electrodes of I G ratio is larger Comparative examples 1 to 3, also include a high oxidizing power manganese ions in the electrolyte of the positive electrode side, the cell resistivity of redox flow batteries, hardly deteriorated by repeated use I understood it.
  • the positive electrode of Examples 1 and 2 since the positive electrode of Examples 1 and 2 has a lower I D /I G ratio in the carbon electrode material, it has a lower cell resistivity in the initial state, and also has a cell resistivity with repeated use. I found it harder to get worse.
  • the positive electrodes of Examples 1 to 3 were manufactured by a method including a high temperature firing step of firing carbon paper at 2300° C. or higher and 3500° C. or lower to obtain a carbon electrode material.
  • the carbon electrode material obtained has a lower I D /I G ratio, and thus has a higher oxidizing power. It was found that even if manganese ions were included in the electrolyte solution on the positive electrode side, the cell resistivity of the redox flow battery was unlikely to deteriorate with repeated use.
  • FIG. 2A is a SEM image of the surface of the carbon fiber before the low temperature firing step
  • FIG. 2B is a carbon fiber before the high temperature firing step after the low temperature firing step. It is a SEM image of the surface. From the comparison of the SEM images of FIG. 2(a) and FIG.
  • the content of the oxygen element contained in the carbon electrode material depends on whether the low temperature firing step is performed in Examples 1 to 3 and Comparative Examples 2 and 3 in which the high temperature firing step was performed at a firing temperature of 2000° C. or higher. Regardless of the relationship, both were low at 0.20% by mass to 0.22% by mass, but in Comparative Example 1 in which the high temperature firing step was not performed, it was remarkably high at 1.00% by mass. From this, the carbon electrode material forming the positive electrode can be suppressed to a low content without increasing the content of oxygen element by performing the high temperature firing step regardless of whether or not the low temperature firing step is performed. all right.

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Abstract

La présente invention concerne : une électrode qui n'est pas sensible à la détérioration due à l'oxydation ; un procédé de production de cette électrode ; et une batterie.　Une électrode selon la présente invention comprend un matériau d'électrode de carbone ; et le matériau d'électrode de carbone a un rapport d'intensité de pic de l'intensité de pic de la bande D (ID) à l'intensité de pic de la bande G (IG), à savoir ID/IG de 0,50 ou moins dans le spectre Raman tel que déterminé par spectroscopie Raman, tout en ayant une teneur en oxygène élémentaire de 0,50 % en masse ou moins. Il est préférable que cette électrode soit utilisée comme électrode positive (111) d'une batterie à flux redox (1).
PCT/JP2020/003162 2019-01-29 2020-01-29 Électrode, son procédé de production et batterie WO2020158797A1 (fr)

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Publication number Priority date Publication date Assignee Title
JP2006008472A (ja) * 2004-06-29 2006-01-12 Hitachi Powdered Metals Co Ltd ナノ構造化黒鉛、その複合材料、これらを用いた導電材料及び触媒材料
JP2011243314A (ja) * 2010-05-14 2011-12-01 Honda Motor Co Ltd 固体高分子型燃料電池用膜電極構造体
JP2015189606A (ja) * 2014-03-27 2015-11-02 旭化成株式会社 導電性グラファイト及び導電性グラファイトの製造方法、並びに透明導電膜
WO2016133132A1 (fr) * 2015-02-18 2016-08-25 新日鐵住金株式会社 Matériau carboné support de catalyseur, catalyseur de pile à combustible à polymère solide, pile à combustible à polymère solide, et procédé de fabrication de matériau carboné support de catalyseur
JP2016528158A (ja) * 2013-08-21 2016-09-15 ハンワ ケミカル コーポレイション グラフェン、グラフェンの製造方法、および製造装置
JP2017208224A (ja) * 2016-05-18 2017-11-24 新日鐵住金株式会社 触媒担体用炭素材料、触媒担体用炭素材料のポリエチレングリコール樹脂吸着量評価試験方法、固体高分子形燃料電池用触媒、固体高分子形燃料電池用触媒層、及び固体高分子形燃料電池
JP2018123447A (ja) * 2017-01-31 2018-08-09 東洋紡株式会社 炭素質材料およびこれを用いた電池

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006008472A (ja) * 2004-06-29 2006-01-12 Hitachi Powdered Metals Co Ltd ナノ構造化黒鉛、その複合材料、これらを用いた導電材料及び触媒材料
JP2011243314A (ja) * 2010-05-14 2011-12-01 Honda Motor Co Ltd 固体高分子型燃料電池用膜電極構造体
JP2016528158A (ja) * 2013-08-21 2016-09-15 ハンワ ケミカル コーポレイション グラフェン、グラフェンの製造方法、および製造装置
JP2015189606A (ja) * 2014-03-27 2015-11-02 旭化成株式会社 導電性グラファイト及び導電性グラファイトの製造方法、並びに透明導電膜
WO2016133132A1 (fr) * 2015-02-18 2016-08-25 新日鐵住金株式会社 Matériau carboné support de catalyseur, catalyseur de pile à combustible à polymère solide, pile à combustible à polymère solide, et procédé de fabrication de matériau carboné support de catalyseur
JP2017208224A (ja) * 2016-05-18 2017-11-24 新日鐵住金株式会社 触媒担体用炭素材料、触媒担体用炭素材料のポリエチレングリコール樹脂吸着量評価試験方法、固体高分子形燃料電池用触媒、固体高分子形燃料電池用触媒層、及び固体高分子形燃料電池
JP2018123447A (ja) * 2017-01-31 2018-08-09 東洋紡株式会社 炭素質材料およびこれを用いた電池

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