WO2020184450A1 - Matériau d'électrode positive de carbone pour batterie redox à base de manganèse et titane, et batterie équipée de celui-ci - Google Patents

Matériau d'électrode positive de carbone pour batterie redox à base de manganèse et titane, et batterie équipée de celui-ci Download PDF

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WO2020184450A1
WO2020184450A1 PCT/JP2020/009754 JP2020009754W WO2020184450A1 WO 2020184450 A1 WO2020184450 A1 WO 2020184450A1 JP 2020009754 W JP2020009754 W JP 2020009754W WO 2020184450 A1 WO2020184450 A1 WO 2020184450A1
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carbonaceous
carbon
graphite particles
electrode material
positive electrode
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PCT/JP2020/009754
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English (en)
Japanese (ja)
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良平 岩原
小林　真申
貴弘 松村
佳奈 森本
伊藤　賢一
吉恭 川越
雄大 池上
康一 橋本
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東洋紡株式会社
住友電気工業株式会社
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Priority to JP2021505033A priority Critical patent/JPWO2020184450A1/ja
Publication of WO2020184450A1 publication Critical patent/WO2020184450A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • 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 a carbon electrode material used for a positive electrode of a manganese / titanium-based redox flow battery. More specifically, the present invention has excellent oxidation resistance and low resistance, and is excellent in energy efficiency of the entire manganese / titanium-based redox flow battery. Regarding carbon positive electrode material.
  • the redox flow battery is a battery that utilizes redox in an aqueous solution of redox flow ions, and is a large-capacity storage battery with extremely high safety because it is a mild reaction only in the liquid phase.
  • the main configuration of the redox flow battery is composed of external tanks 6 and 7 for storing electrolytic solutions (positive electrode electrolytic solution, negative electrode electrolytic solution) and an electrolytic cell EC.
  • the electrolytic cell EC the ion exchange membrane 3 is arranged between the opposing current collector plates 1 and 1.
  • the electrolytic solution containing the active material is sent from the external tanks 6 and 7 to the electrolytic cell EC by the pumps 8 and 9, and the electrochemical energy conversion, that is, is performed on the electrode 5 incorporated in the electrolytic cell EC. Charging and discharging are performed.
  • an aqueous solution containing a metal ion whose valence changes due to redox is typically used as the electrolytic solution used in the redox flow battery.
  • the electrolytic solution has changed from a type in which an aqueous solution of iron hydrochloric acid is used for the positive electrode and an aqueous solution of chromium in hydrochloric acid for the negative electrode to a type in which a sulfuric acid aqueous solution of vanadium having a high electromotive force is used for both electrodes, and the energy density has been increased.
  • the electrolytic solution containing V 2+ is supplied to the liquid passage on the negative electrode side during discharge, and the positive electrode is positive.
  • An electrolytic solution containing V 5+ (actually an ion containing oxygen) is supplied to the liquid passage on the side.
  • V 2+ emits electrons in the three-dimensional electrode and is oxidized to V 3+ .
  • the emitted electrons reduce V 5+ to V 4+ (actually oxygen-containing ions) in the three-dimensional electrode on the positive electrode side through an external circuit.
  • the electrode materials for redox flow batteries are particularly required to have the following performance.
  • Patent Document 1 discloses a carbonaceous material having a specific pseudographite microcrystal structure with high crystallinity as an electrode material of an Fe—Cr battery capable of increasing the total energy efficiency of the battery. Specifically, it has pseudographite microcrystals having an average ⁇ 002> plane spacing of 3.70 ⁇ or less and an average crystallite size of 9.0 ⁇ or more in the c-axis direction obtained by X-ray wide-angle analysis.
  • a carbonaceous material having a total acidic functional group amount of at least 0.01 meq / g is disclosed.
  • Patent Document 2 describes a carbonaceous fiber made from polyacrylonitrile fiber as an electrode for an electric field layer of an iron-chromium-based redox flow battery or the like that enhances the energy efficiency of the battery and improves the charge / discharge cycle life.
  • Patent Document 3 describes the ⁇ 002> plane spacing obtained from X-ray wide-angle analysis as a carbon electrode material for vanadium-based redox flow batteries, which has excellent energy efficiency in the entire battery system and has little change in performance with long-term use. It has a pseudo-graphite crystal structure of 3.43 to 3.60 ⁇ , a crystallite size of 15 to 33 ⁇ in the c-axis direction, and a crystallite size of 30 to 75 ⁇ in the a-axis direction, and XPS surface analysis.
  • An electrode is disclosed in which the amount of surface acidic functional groups obtained from the above is 0.2 to 1.0% of the total number of surface carbon atoms, and the number of surface-bonded nitrogen atoms is 3% or less of the total number of surface carbon atoms.
  • the crystal structure on the carbonaceous fiber was obtained by X-ray wide-angle analysis as a carbon electrode material that enhances the overall efficiency of the vanadium-based redox flow battery and lowers the cell resistance at the time of initial charging.
  • 002> It is composed of a carbon composite material to which carbon fine particles having an average primary particle diameter of 30 nm or more and 5 ⁇ m or less are attached, and the surface spacing is 3.43 to 3.70 ⁇ .
  • carbonaceous fibers and carbon fine particles are preferably adhered to each other in close proximity or by an adhesive such as phenol resin, and by using the adhesive, carbon which is an electrochemical reaction field is used. It is stated that only the originally contacted portion of the carbonaceous fiber can be fixed without excessively reducing the surface of the quality fiber.
  • the non-woven fabric is dipped in a solution containing 5% by weight (Example 1) of carbon fine particles (phenolic resin) or 5% by weight (Examples 2 to 4) of phenolic resin, and then carbonized.
  • a carbonized fiber non-woven fabric obtained by a dry oxidation treatment is disclosed.
  • Patent Document 5 For example, a manganese / titanium-based electrolyte has been proposed in which manganese is used for the positive electrode and chromium, vanadium, or titanium is used for the negative electrode.
  • Japanese Unexamined Patent Publication No. 60-232669 Japanese Unexamined Patent Publication No. 5-234612 Japanese Unexamined Patent Publication No. 2000-357520 Japanese Unexamined Patent Publication No. 2017-33758 Japanese Unexamined Patent Publication No. 2012-204135
  • the electrode material used for the vanadium-based electrolytic solution as in Patent Documents 2 to 4 is a redox flow battery using the manganese / titanium-based electrolytic solution described in Patent Document 5 (hereinafter, manganese / titanium-based redox flow battery). It has been found that when used as a carbonaceous electrode material (which may be abbreviated), the cell resistance increases remarkably during the initial charge and discharge, and the battery energy efficiency decreases.
  • Mn ions are unstable in an aqueous solution and the reaction rate is slow, so that the cell resistance increases. It was also found that the electrode material deteriorates because the oxidizing power of Mn ions (positive electrode charging liquid) generated during charging is very strong.
  • oxidation resistance to Mn ions is a characteristic strongly required for the positive electrode material of a manganese / titanium-based redox flow battery, and the above problem can be solved only by using the electrode material for the redox flow battery described in Patent Documents 2 to 4 described above. It was found that it was difficult to achieve both high oxidation resistance and low resistance. 2Mn 3+ + 2H 2 O ⁇ Mn 2+ + MnO 2 + 4H -
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to improve the oxidation resistance to Mn ions (positive electrode charging liquid) even when a manganese / titanium-based electrolytic solution is used. It is an object of the present invention to provide a carbon positive electrode electrode material for a manganese / titanium-based redox flow battery, which can reduce cell resistance at the time of initial charge / discharge and improve battery energy efficiency.
  • the configuration of the carbon positive electrode material for a manganese / titanium-based redox flow battery according to the present invention that could solve the above problems is as follows.
  • a carbon positive electrode material for a manganese / titanium-based redox flow battery which is characterized by satisfying the following requirements.
  • the particle size of the graphite particles (B) is 1 ⁇ m or more.
  • Lc (B) When the size of the crystallites in the c-axis direction obtained by X-ray diffraction in the graphite particles (B) is Lc (B), Lc (B) is 35 nm or more.
  • Lc (C) When the size of crystallites in the c-axis direction obtained by X-ray diffraction in the carbonaceous material (C) is Lc (C), Lc (C) is 10 nm or more. (4) When the size of the crystallites in the c-axis direction obtained by X-ray diffraction in the carbonaceous fiber (A) is Lc (A), Lc (C) / Lc (A) is 1.0 or more. (5) The number of bound oxygen atoms on the surface of the carbon positive electrode material is less than 1.0% of the total number of carbon atoms on the surface of the carbon positive electrode material. (6) The BET specific surface area determined from the amount of nitrogen adsorbed is 0.5 to 1.5 m 2 / g. 2. 2.
  • the mass content of the graphite particles (B) and the carbonaceous material (C) with respect to the total amount of the carbonaceous fiber (A), the graphite particles (B), and the carbonaceous material (C) is 20% or more, respectively.
  • a manganese / titanium-based redox flow battery provided with the carbon positive electrode material according to any one of 1 to 4 above.
  • the carbon positive electrode material of the present invention can realize both high oxidation resistance and low resistance, and is therefore particularly useful as a positive electrode material for manganese / titanium-based redox flow batteries. Further, the carbon positive electrode material of the present invention is suitably used for flow type and non-flow type redox batteries, or manganese / titanium-based redox flow batteries combined with a lithium, capacitor, and fuel cell system.
  • FIG. 1 is a schematic view of a redox flow battery.
  • FIG. 2 is an exploded perspective view of a liquid flow type electrolytic cell having a three-dimensional electrode preferably used in the present invention.
  • FIG. 3 shows No. 2A in Table 2A in Example 2 described later. It is an SEM photograph (magnification 100 times) of 1 (an example which satisfies the requirement of this invention).
  • FIG. 4 shows No. 2A in Table 2A in Example 2 described later. 13 (comparative example not satisfying the requirements of the present invention) SEM photograph (magnification 100 times).
  • the present inventors have been diligently studying to provide a carbon electrode material preferably used for the positive electrode of a manganese / titanium-based redox flow battery using Mn ion as the positive electrode active material and Ti ion as the negative electrode active material. ..
  • a carbon electrode material preferably used for the positive electrode of a manganese / titanium-based redox flow battery using Mn ion as the positive electrode active material and Ti ion as the negative electrode active material. ..
  • Mn ion as the positive electrode active material
  • Ti ion as the negative electrode active material
  • carbon blacks such as acetylene black (acetylene soot), oil black (furness black, oil soot), and gas black (gas soot) are used as particles showing reaction activity in redox flow batteries; Soot, carbon fiber powder, carbon nanotubes (CNT, carbon nanotube), carbon nanofibers, carbon aerogel, mesoporous carbon, glassy carbon powder, activated carbon, graphene, graphene oxide, N-doped CNT, boron-doped CNT, Known carbon particles such as carbon particles such as fullerene, petroleum coke, acetylene coke, and smokeless carbon coke can be mentioned.
  • carbon blacks having high reactivity and specific surface area and low crystallinity cannot be used because they are easily oxidized to the charging liquid of positive electrode manganese.
  • these are rare and expensive, so they are not suitable as inexpensive electrode materials.
  • the present inventors have focused on graphite particles as particles exhibiting reactivity, and have decided to adopt highly crystalline graphite particles satisfying the following requirements (1) and (2) as the graphite particles (B). did.
  • the particle size is 1 ⁇ m or more.
  • Lc (B) When the size of the crystallites in the c-axis direction determined by X-ray diffraction in the graphite particles (B) is Lc (B), Lc (B) is 35 nm or more. It has been found that if graphite particles satisfying these requirements are used, the carbon edge surface as a reaction field can be exposed without excess or deficiency, and both low resistance and high oxidation resistance can be achieved at the same time.
  • the carbonaceous material (C) is a binding carbonaceous material that binds both carbonaceous fibers (A) and graphite particles (B), and satisfies the following requirements (3) and (4).
  • Lc (C) / Lc (A) is 1.0 or more.
  • both carbonaceous fibers (A) and graphite particles (B) (In other words, the carbonaceous material used in the present invention acts as a binder between the carbonaceous fiber and the graphite particles) means that the carbonaceous material acts as a binder on the surface of the carbonic fiber and the graphite particles and The inside (between carbonaceous fibers, including graphite particles) is strongly bonded, and when the electrode material as a whole is viewed, the carbonaceous fibers are covered with the carbonaceous material, and the surface of the graphite particles is exposed. It means that it is configured in. However, it is preferable that the carbonaceous material after binding does not form a film.
  • not in a film state means that the carbonaceous material (C) does not form a webbed state like a whole foot (boxoku) or a foot in the carbonaceous fibers (A). This is because when the film state is formed, the liquid permeability of the electrolytic solution deteriorates, and the reaction surface area of the graphite particles cannot be effectively used.
  • FIG. 3 shows an SEM photograph showing a state in which both carbonaceous fibers (A) and graphite particles (B) are bound in the electrode material of the present invention.
  • FIG. 3 shows No. 2A in Table 2A in Example 2 described later. 1 (an example of the present invention satisfying the requirements of the present invention) is an SEM photograph (magnification 100 times). From FIG. 3, the carbonaceous material (C) strongly binds the surface and the inside of the carbonaceous fiber (A) and the graphite particles (B), and the carbonaceous material (C) coats the carbonaceous fiber (A). It can be seen that the surface of the graphite particles (B) is exposed. On the other hand, FIG.
  • FIG. 4 is an SEM photograph showing a state in which both the carbonaceous fiber (A) and the graphite particles (B) are not bound in the electrode material of the present invention.
  • FIG. 4 shows No. 2A in Table 2A in Example 2 described later. 13 (comparative example not satisfying the requirements of the present invention) SEM photograph (magnification 100 times).
  • the carbonaceous material in the present invention is different from the carbonaceous material described in Patent Document 4 described above.
  • the carbonaceous material used exhibits an action as a partial adhesive based on the idea that only the portion where the carbonaceous fiber and the carbon fine particles originally contacted can be fixed (adhered). This is because there is only recognition that it should be done. Therefore, in the examples of Patent Document 4, the content of the carbonaceous material is at most 14.4% by mass.
  • the carbonaceous material strongly binds between carbonaceous fibers via graphite particles, so that an efficient conductive path can be formed, and the above-mentioned addition of graphite particles enables the formation of an efficient conductive path. It was found that the action was exerted more effectively and both low resistance and high oxidation resistance could be achieved.
  • the carbon positive electrode material of the present invention satisfies the following requirement (5).
  • (5) When the number of bound oxygen atoms on the surface of the carbon positive electrode material is less than 1.0% of the total number of carbon atoms on the surface of the carbon positive electrode material, the ratio of the number of bound oxygen atoms to the total number of carbon atoms is calculated by O / C. It may be abbreviated.
  • O / C the ratio of the number of bound oxygen atoms to the total number of carbon atoms. It may be abbreviated.
  • reducing the O / C to less than 1.0% results in lower resistance. It has become clear that both high oxidation resistance can be achieved.
  • the present inventors used an electrode material in which the amount of oxygen atoms introduced was small and the O / C was controlled to less than 1.0% for a manganese / titanium-based redox flow battery, and surprisingly, the oxidation resistance was improved.
  • the carbon positive electrode material of the present invention satisfies the following requirement (6).
  • the BET specific surface area determined from the amount of nitrogen adsorbed is 0.5 to 1.5 m 2 / g.
  • the BET specific surface area is also a requirement that contributes to both low resistance and high oxidation resistance.
  • oxygen atoms when oxygen atoms are introduced, the BET specific surface area of the electrode material also increases with defects in the carbon structure.
  • the O / C is controlled to less than 1.0% from the viewpoint that the graphite particles need only be exposed, the BET specific surface area hardly increases and is derived from the carried graphite particles.
  • the BET surface area is within the above range, the effect of adding graphite particles is effectively exhibited and a desired effect can be obtained.
  • it is 0.5 to 1.0 m 2 / g.
  • the electrode material of the present invention is configured as described above, it is possible to obtain an electrode having low resistance and long life by increasing reaction activity while maintaining high oxidation resistance.
  • an electrode material for an electrolytic cell of a positive electrode manganese-based redox flow battery it is possible to reduce cell resistance during initial charge and discharge, improve battery energy efficiency, and improve oxidation resistance to positive electrode charging liquid. It becomes possible to provide an excellent carbon positive electrode material.
  • FIG. 2 is an exploded perspective view of a liquid flow type electrolytic cell preferably used in the present invention.
  • an ion exchange membrane 3 is arranged between two opposing current collector plates 1, 1, and spacers 2 are provided on both sides of the ion exchange membrane 3 along the inner surfaces of the current collector plates 1, 1.
  • Passage passages 4a and 4b for the electrolytic solution are formed.
  • the electrode material 5 is arranged in at least one of the liquid passages 4a and 4b.
  • the current collector plate 1 is provided with a liquid inlet 10 and a liquid outlet 11 for the electrolytic solution. As shown in FIG.
  • the current collector plate 1 transports electrons. It is possible to improve the charge / discharge efficiency by using the entire surface of the pores of the electrode material 5 as an electrochemical reaction field while ensuring the above. As a result, the charging / discharging efficiency of the electrolytic cell is improved.
  • the electrode material 5 of the present invention is an electrode material using carbonaceous fiber (A) as a base material and carrying graphite particles (B) with a highly crystalline carbonaceous material (C). Satisfy the requirements of (6). The details of each requirement are as follows.
  • the carbonaceous fiber used in the present invention means a fiber obtained by heat-carbonizing a precursor of an organic fiber (details will be described later), and means a fiber in which 90% or more is composed of carbon in terms of mass ratio.
  • Precursors of organic fibers used as raw materials for carbonaceous fibers include acrylic fibers such as polyacrylonitrile; phenol fibers; PBO fibers such as polyparaphenylene benzobisoxazole (PBO); aromatic polyamide fibers; isotropic pitch and heterogeneity.
  • Pitch fibers such as sex pitch fibers and mesophase pitch; cellulose fibers; and the like can be used.
  • acrylic fiber acrylic fiber, phenol fiber, cellulose fiber, isotropic pitch fiber, and anisotropic pitch fiber are preferable as the precursor of the organic fiber from the viewpoint of excellent oxidation resistance, strength and elasticity, and acrylic.
  • Fiber is more preferred.
  • the acrylic fiber is not particularly limited as long as it contains acrylonitrile as a main component, but the content of acrylonitrile in the raw material monomer forming the acrylic fiber is preferably 95% by mass or more, preferably 98% by mass or more. Is more preferable.
  • the mass average molecular weight of the organic fiber is not particularly limited, but is preferably 10,000 or more and 100,000 or less, more preferably 15,000 or more and 80,000 or less, and further preferably 20,000 or more and 50,000 or less.
  • the mass average molecular weight can be measured by a method such as gel permeation chromatography (GPC) or solution viscosity.
  • the average fiber diameter of carbonaceous fibers is preferably 0.5 to 40 ⁇ m. If the average fiber diameter is smaller than 0.5 ⁇ m, the liquid permeability will deteriorate. On the other hand, if the average fiber diameter is larger than 40 ⁇ m, the reaction surface area of the fiber portion decreases and the cell resistance increases. Considering the balance between liquid permeability and reaction surface area, it is more preferably 3 to 20 ⁇ m.
  • the carbonaceous fiber structure as a base material, which improves the strength and facilitates handling and processability.
  • the structure include spun yarn, filament-focused yarn, non-woven fabric, knitted fabric, and woven fabric, which are sheet-like materials made of carbon fiber, and special knitted fabric or carbon described in JP-A-63-240177.
  • Examples include paper made of fibers.
  • non-woven fabrics made of carbon fibers, knitted fabrics, woven fabrics, special woven knitted fabrics, and paper made of carbon fibers are more preferable from the viewpoints of handling, processability, manufacturability, and the like.
  • the average fiber length is preferably 30 to 100 mm.
  • the average fiber length is preferably 5 to 30 mm.
  • the carbonaceous fiber is obtained by heat-carbonizing a precursor of an organic fiber, but the above-mentioned "heat carbonization treatment” includes at least a flame resistance step and a carbonization (calcination) step. Is preferable.
  • the carbonization step does not necessarily have to be performed after the flame resistance step as described above, and after the graphite particles and the carbonaceous material are attached to the flame resistant fibers as described in Examples described later.
  • a carbonization step may be performed, and in this case, the carbonization step after the flame resistance step can be omitted.
  • the flame-resistant step means a step of heating an organic fiber precursor preferably at a temperature of 180 ° C. or higher and 350 ° C. or lower in an air atmosphere to obtain a flame-resistant organic fiber.
  • the heat treatment temperature is more preferably 190 ° C. or higher, and even more preferably 200 ° C. or higher. Further, it is preferably 330 ° C. or lower, and more preferably 300 ° C. or lower.
  • the organic fibers may be thermally shrunk and the molecular orientation may be disrupted to reduce the conductivity of the carbonaceous fibers. Therefore, it is preferable to perform the flame resistance treatment of the organic fibers under tension or stretching. It is more preferable to carry out flameproofing treatment under tension.
  • the flame-resistant organic fibers obtained as described above are preferably heated at a temperature of 1000 ° C. or higher and 2000 ° C. or lower in an inert atmosphere (preferably in a nitrogen atmosphere) to obtain carbonic fibers.
  • the heating temperature is more preferably 1100 ° C. or higher, and even more preferably 1200 ° C. or higher. Further, it is more preferably 1900 ° C. or lower.
  • the heating temperature in the carbonization step can be selected according to the type of the organic fiber used as a raw material.
  • the heating temperature is preferably 800 ° C. or higher and 2000 ° C. or lower, and more preferably 1000 ° C. or higher and 1800 ° C. or lower.
  • the flame resistance step and carbonization step described above are preferably carried out continuously, and the rate of temperature rise when the temperature is raised from the flame resistance temperature to the carbonization temperature is preferably 20 ° C./min or less, more preferably. Is 15 ° C./min or less.
  • the rate of temperature rise is preferably 5 ° C./min or more in consideration of mechanical properties and the like.
  • the electrode material of the present invention is a carbonaceous fiber (A) and a carbonaceous material (C) as defined in (4) above.
  • Lc (A) and Lc (C) are Lc (A) and Lc (C), respectively.
  • Lc (C) / Lc (A) satisfies 1.0 or more. Therefore, in the present invention, Lc (A) in the carbonaceous fiber (A) is not particularly limited as long as the above (4) is satisfied, but it is preferably 1 to 15 nm.
  • Lc (A) is more preferably 2 to 10 nm. The method for measuring Lc (A) will be described in detail in the column of Examples described later.
  • Graphite particles (B) are necessary to increase the change in valence (reactivity) due to redox and obtain high oxidation resistance.
  • the carbon edge surface which is the reaction field, is necessary for exhibiting high reactivity, but excessive exposure of the edge surface causes a decrease in oxidation resistance.
  • Lc (B) the size of the crystallites in the c-axis direction obtained by X-ray diffraction
  • the value of Lc (B) is the value of the carbon edge surface. We found that it correlates with the degree of exposure.
  • Lc (B) is 35 nm or more, preferably 37 nm or more.
  • the upper limit of the above value is not particularly limited from the above viewpoint, but it is preferably about 50 nm or less in consideration of the balance between oxidation resistance and low resistance.
  • Graphite particles are generally roughly classified into natural graphite and artificial graphite.
  • natural graphite include scaly graphite, scaly graphite, earthy graphite, spheroidal graphite, flaky graphite and the like
  • artificial graphite include expanded graphite and graphite oxide.
  • graphite oxide, scaly graphite, scaly graphite, earthy graphite, flaky graphite, and expanded graphite are carbon as a reaction field. It is preferable because it has an edge surface.
  • scaly graphite, flaky graphite, and expanded graphite are more preferable because the carbon edge surface is very exposed and low resistance can be obtained, and the cost is low and the amount of resources is abundant.
  • These scaly graphite, flaky graphite, and expanded graphite may be added alone, or two or more of them may be mixed and used.
  • scaly graphite means that the appearance is leaf-like.
  • Scaly graphite is different from scaly graphite (which is lumpy in shape and is sometimes referred to as lump graphite).
  • the graphite particles (B) used in the present invention have a particle size of 1 ⁇ m or more, preferably 3 ⁇ m or more.
  • the particle size is less than 1 ⁇ m, the ratio of being buried in the carbonaceous material increases, and graphite particles appear on the surface in a small amount, so that the specific surface area of the carbonaceous material increases too much.
  • the effect of improving the oxidation resistance by adding the graphite particles (B) is not effectively exhibited, and the oxidation resistance tends to decrease.
  • the specific surface area of the carbonaceous material is increased, the reason why the effect of improving the oxidation resistance is not effectively exhibited is presumed as follows.
  • the “particle size” means the average particle size (D50) at a median 50% diameter in the particle size distribution obtained by a dynamic light scattering method or the like.
  • D50 average particle size
  • Commercially available products may be used as the graphite particles, in which case the particle size described in the catalog can be adopted.
  • the graphite particles (B) used in the present invention are contained in an amount of 20% or more in terms of mass ratio to the total amount of the carbonaceous fibers (A), the graphite particles (B), and the carbonaceous material (C) described later. It is preferably 25% or more, and more preferably 25% or more. As a result, the above-mentioned effect due to the addition of graphite particles is effectively exhibited, and the oxidation resistance is particularly improved.
  • the upper limit is not particularly limited from the viewpoint of oxidation resistance and the like, but it is preferably about 60% or less in consideration of the balance between oxidation resistance and low resistance.
  • the content of the carbonaceous fiber (A) used for calculating the above content is the content of the structure when a structure such as a non-woven fabric is used as the base material.
  • the mass ratio of the carbonaceous material (C) described later to the graphite particles (B) is preferably 0.2 or more and 3.0 or less, and preferably 0.3 or more and 2.5 or less. More preferred. If the above ratio is less than 0.2, graphite particles are often shed off, and the effect of adding graphite is not particularly effective in improving the oxidation resistance. On the other hand, if the above ratio exceeds 3.0, the carbon edge surface of the graphite particles, which is the reaction field, is covered, and the desired low resistance cannot be obtained.
  • BET specific surface area determined from nitrogen adsorption amount is preferably 3 ⁇ 20m 2 / g, more preferably 5 ⁇ 15m 2 / g.
  • the BET specific surface area is less than 3 m 2 / g, the exposure of the edge surface of the graphite particles (B) is reduced, so that the desired low resistance cannot be obtained.
  • the BET specific surface area is 20 m 2 / g or more, the specific surface area increases too much and the effect of improving the oxidation resistance by adding the graphite particles (B) is not effectively exhibited, and the oxidation resistance tends to decrease.
  • the above-mentioned "BET specific surface area obtained from the amount of adsorbed nitrogen” means the specific surface area calculated from the amount of gas molecules adsorbed by adsorbing gas molecules on solid particles.
  • Carbonaceous material (C) The carbonaceous material used in the present invention is added as a binder for strongly binding carbonaceous fibers and graphite particles, which cannot be bound originally, and is a carbonaceous material having poor oxidation resistance. It has the effect of protecting the fibers.
  • Lc (C) when the size of the crystallite in the c-axis direction obtained by X-ray diffraction in the carbonaceous material (C) is Lc (C) as defined in (3) above, Lc (C) is When the size of the crystallites in the c-axis direction in the carbonaceous fiber (A) determined by X-ray diffraction is Lc (A) as defined in (4) above and is 10 nm or more, Lc.
  • Lc (C) is preferably 10 nm or more, and more preferably 12 nm or more.
  • the upper limit of Lc (C) is not particularly limited from the above viewpoint, but it is preferably 40 nm or less in consideration of both oxidation resistance and low resistance.
  • the ratio of Lc (C) / Lc (A) is less than 1.0, the above effect will not be effectively exhibited.
  • the above ratio is preferably 2 or more, and more preferably 3 or more. On the other hand, if the above ratio exceeds 10, it becomes difficult to achieve both low resistance.
  • the above ratio is preferably 8 or less.
  • the carbonaceous material (C) used in the present invention contains 20% or more of the above-mentioned carbonaceous fiber (A), graphite particles (B), and carbonaceous material (C) in terms of mass ratio to the total amount. Is preferable, and 30% or more is more preferable.
  • the upper limit is not particularly limited from the viewpoint of oxidation resistance and the like, but it is preferably about 60% or less in consideration of the liquid pressure loss and the like. More preferably, it is 50% or less.
  • the type of carbonaceous material (C) used in the present invention may be any as long as it can bind carbonaceous fibers (A) and graphite particles (B), and specifically, at the time of producing the electrode material of the present invention. It is not particularly limited as long as it exhibits binding property at the time of carbonization. Examples of such are pitches such as coal tar pitch and coal pitch; phenol resin, benzoxazine resin, epoxide resin, furan resin, vinyl ester resin, melanin-formaldehyde resin, urea-formaldehyde resin, resorcinol-formaldehyde.
  • pitches such as coal tar pitch and coal pitch
  • phenol resin benzoxazine resin, epoxide resin, furan resin, vinyl ester resin, melanin-formaldehyde resin, urea-formaldehyde resin, resorcinol-formaldehyde.
  • resins such as resins, cyanate ester resins, bismaleimide resins, polyurethane resins and polyacrylonitrile; furfuryl alcohols; rubbers such as acrylonitrile-butadiene rubber.
  • resins such as resins, cyanate ester resins, bismaleimide resins, polyurethane resins and polyacrylonitrile
  • furfuryl alcohols such as acrylonitrile-butadiene rubber.
  • rubbers such as acrylonitrile-butadiene rubber.
  • Commercially available products may be used for these.
  • pitches such as coal tar pitch and carboniferous pitch, which are particularly easily crystalline, are preferable because the desired carbonaceous material (C) can be obtained at a low firing temperature.
  • the polyacrylonitrile resin is also preferably used because the desired carbonaceous material (C) can be obtained by raising the firing temperature. Pitches are particularly preferable.
  • the phenol resin since the phenol resin is not used, there are merits such as no harmful effects (formaldehyde generation at room temperature and formaldehyde odor) associated with the phenol resin, and no odor is generated at room temperature.
  • Patent Document 4 uses a phenol resin as an adhesive, in addition to the above-mentioned adverse effects, a separate facility for controlling the formaldehyde concentration in the work place to the control concentration or less is required, which is a cost aspect. , There are disadvantages in terms of work.
  • the pitches that are particularly preferably used will be described in detail.
  • the content of the mesophase phase liquid crystal phase
  • the content of the mesophase phase can be controlled by the temperature and time of the infusibilization treatment. If the content of the mesophase phase is low, one that melts at a relatively low temperature or is in a liquid state at room temperature can be obtained. On the other hand, if the content of the mesophase phase is high, it melts at a high temperature and a high carbonization yield can be obtained.
  • the content of the mesophase phase is preferably high (that is, the carbonization rate is high), for example, 30% or more is preferable, and 50% or more is more preferable.
  • the fluidity at the time of melting can be suppressed, and the carbonaceous fibers can be bound to each other through the graphite particles without excessively covering the surface of the graphite particles.
  • the upper limit is preferably 90% or less, for example, in consideration of the expression of binding property.
  • the melting point of the pitches is preferably 100 ° C. or higher, more preferably 200 ° C. or higher.
  • the upper limit is preferably 350 ° C. or lower, for example, in consideration of the development of binding property.
  • the electrode material of the present invention satisfies that the number of bound oxygen atoms on the surface of the carbon positive electrode material is less than 1.0% of the total number of carbon atoms on the surface of the carbon positive electrode material (O / C ⁇ 1.0%).
  • O / C can be measured by surface analysis such as X-ray photoelectron spectroscopy (XPS) and fluorescent X-ray analysis.
  • the defect structure of the carbonaceous material (C) portion is reduced, and high durability can be obtained. Further, if the structure is such that the graphite particles can be sufficiently exposed, low resistance can be maintained. On the other hand, if an electrode material having an O / C of 1.0% or more and a high oxygen concentration is used, the defect structure of the carbonaceous material (C) portion increases, and the durability cannot be improved. As a result, the life is shortened.
  • the electrode material of the present invention satisfies the BET specific surface area of 0.5 to 1.5 m 2 / g determined from the amount of nitrogen adsorbed. If the BET specific surface area is less than 0.5 m 2 / g, the exposure of the edge surface of the graphite particles (B) is reduced, so that the desired low resistance cannot be obtained.
  • the preferred upper limit is 1.0 m 2 / g.
  • the BET specific surface area exceeds 1.5 m 2 / g, the specific surface area increases too much and the effect of improving the oxidation resistance by adding the graphite particles (B) is not effectively exhibited, and the oxidation resistance tends to decrease. ..
  • the basis weight of the electrode material of the present invention is 50 to 50 when the thickness of the spacer 2 sandwiched between the current collector plate 1 and the ion exchange membrane 3 (hereinafter referred to as "spacer thickness") is 0.3 to 3 mm. 500 g / m 2 is preferable, and 100 to 400 g / m 2 is more preferable.
  • spacer thickness the thickness of the ion exchange membrane 3 tends to be thin, and treatment and usage methods for reducing damage to the ion exchange membrane 3 are extremely important.
  • a non-woven fabric or paper having a flat surface processed on one side as a base material as the electrode material of the present invention.
  • Any known method can be applied to the flattening method, and examples thereof include a method of applying a slurry to one side of a carbonaceous fiber and drying it; a method of impregnation and drying on a smooth film such as PET.
  • the thickness of the electrode material of the present invention is preferably at least larger than the spacer thickness.
  • the spacer thickness is 1.5 to 1.5 to. 6.0 times is preferable.
  • the ion exchange membrane 3 may be pierced by the compressive stress of the sheet-like material. Therefore, it is recommended to use the electrode material of the present invention having a compressive stress of 9.8 N / cm 2 or less. preferable.
  • the electrode material of the present invention in order to adjust the compressive stress and the like according to the basis weight and thickness of the electrode material of the present invention, it is also possible to use the electrode material of the present invention in a laminated manner such as two layers or three layers. Alternatively, it can be combined with another form of electrode material.
  • the electrode material of the present invention can be produced by adhering graphite particles and a precursor of a carbonaceous material (before carbonization) to a carbonaceous fiber (base material), and then undergoing a carbonization step and a graphitization step. .. In each step, a known method can be arbitrarily applied. In the present invention, in order to control the O / C to less than 1.0%, the oxidation treatment step (dry air oxidation) usually performed after the graphitization step is not performed.
  • Step of adhering graphite particles and precursors of carbonaceous material to carbonaceous fibers First, graphite particles and precursors of carbonaceous material are attached to carbonaceous fibers.
  • a known method can be arbitrarily adopted for adhering the graphite particles and the precursor of the carbonaceous material to the carbonaceous fiber. For example, a method of heating and melting the above-mentioned carbonaceous material precursor, dispersing graphite particles in the obtained melt, immersing carbonaceous fibers in the melt dispersion, and then cooling to room temperature can be mentioned.
  • the above carbonaceous material precursor and graphite particles are mixed with a solvent such as water or alcohol to which a binder (temporary adhesive) that disappears during carbonization such as polyvinyl alcohol is added.
  • a method can be used in which the carbonaceous fibers are dispersed, the carbonaceous fibers are immersed in the dispersion, and then heated and dried.
  • the excess liquid among the melt dispersion liquid and the dispersion liquid in which the carbonaceous fiber is immersed can be passed through a nip roller provided with a predetermined clearance to squeeze the excess dispersion liquid when immersed in the dispersion liquid.
  • the surface of the excess dispersion liquid when immersed in the dispersion liquid with a doctor blade or the like can be removed by scraping the surface.
  • the carbonization step is performed to calcin the product after the attachment obtained in the above step. As a result, carbonaceous fibers are bound to each other via graphite particles.
  • the heating temperature is more preferably 1000 ° C. or higher, further preferably 1200 ° C. or higher, even more preferably 1300 ° C. or higher, still more preferably 1500 ° C. or lower, still more preferably 1400 ° C. or lower.
  • the treatment corresponding to the carbonization step may be performed even after the fiber is made flame resistant, but the carbonization treatment performed after the fiber is made flame resistant may be omitted. That is, the method for producing the electrode material of the present invention is roughly classified into the following method 1 and method 2.
  • Method 1 Flame resistance of fiber ⁇ Carbonization of fiber ⁇ Adhesion of graphite particles and carbonaceous material ⁇ Carbonization ⁇ Graphite formation
  • Method 2 Flame resistance of fiber ⁇ Adhesion of graphite particles and carbonaceous material ⁇ Carbonization ⁇ Graphite According to the above method 1, the processing cost increases because carbonization is performed twice, but the sheet used as the electrode material is not easily affected by the difference in volume shrinkage ratio, so that the obtained sheet is deformed (warpage occurs). It has the advantage of being difficult to do.
  • the processing cost can be reduced because the carbonization step may be performed once, but the sheet obtained by the difference in the volume shrinkage ratio at the time of carbonization of each material is easily deformed. Which of the above methods 1 and 2 should be adopted may be appropriately determined in consideration of these.
  • the graphitization step is a step performed in order to sufficiently enhance the crystallinity of the carbonaceous material and to exhibit high oxidation resistance.
  • the mixture is further heated in an inert atmosphere (preferably in a nitrogen atmosphere) at a temperature of 1800 ° C. or higher, which is higher than the heating temperature in the carbonization step, preferably 2000 ° C.
  • the above is more preferable.
  • the upper limit is preferably 3000 ° C. or lower in consideration of the load on the equipment.
  • Patent Document 4 described above is different from the production method of the present invention in that the graphitization step is not performed. Therefore, the electrode material of Patent Document 4 does not satisfy the requirement of the present invention [Lc of carbonaceous material (C) is 10 nm or more].
  • the oxidation treatment since the O / C is controlled to less than 1.0%, the oxidation treatment usually performed after the graphitization step is not performed.
  • the oxidation treatment is carried out to introduce an oxygen functional group such as a hydroxyl group, a carbonyl group, a quinone group, a lactone group or a free radical oxide to the surface of the electrode material, and the O / C is carried out by the oxidation treatment. This is because is increased to 1.0% or more.
  • Lc (A) of carbonaceous fiber, Lc (B) of graphite particles, and Lc (C) of carbonaceous material. ) was measured as follows. Each of the carbonaceous fibers, graphite particles, and carbonaceous material (single substance) used in this example was sequentially subjected to the same heat treatment as in Example 2, and the measurement was performed using the final treated sample. Basically, carbon crystallinity is dominated by the influence of thermal energy given to the sample, and it is thought that the thermal history of the highest temperature given to the sample determines the crystallinity of Lc, but it depends on the degree of subsequent oxidation treatment. It is considered that the graphene laminated structure formed during the graphitization step is disturbed, and the crystallinity may be lowered due to the generation of defective structures. Therefore, the final processed sample was used.
  • the carbonaceous fibers (A) and graphite particles (B) used for the electrode material of the present invention, and the carbonaceous material (C) for binding them are peak-separated from the chart obtained by the above wide-angle X-ray measurement. Therefore, each Lc value was calculated. Specifically, the peak where the apex is seen in the range of 26.4 ° to 26.6 °, which is twice the diffraction angle ⁇ (2 ⁇ ), is the graphite particle (B), and the range of 25.7 ° to 26.2 °. The peak in which the apex is seen was defined as the carbonaceous material (C).
  • each Lc was calculated by the following method.
  • the wavelength ⁇ 1.5418 ⁇
  • the structural coefficient k 0.9
  • ⁇ indicates the half width of the ⁇ 002> diffraction peak
  • ⁇ indicates the ⁇ 002> diffraction angle.
  • BET specific surface area measurement Approximately 100 mg of a sample was collected, vacuum dried at 120 ° C. for 12 hours, weighed 90 g, and the BET specific surface area was measured using a specific surface area / pore distribution measuring device Gemini2375 (manufactured by Micromeritics). It was measured. Specifically, the amount of nitrogen gas adsorbed at the boiling point (-195.8 ° C.) of liquid nitrogen was measured in a relative pressure range of 0.02 to 0.95, and an adsorption isotherm of the sample was prepared. Based on the results in the range of relative pressure 0.02 to 0.15, the BET specific surface area per weight (unit: m 2 / g) was determined by the BET method.
  • Each electrode material obtained by the method described later is cut out into an electrode area of 8.91 cm 2 with an electrode area of 2.7 cm in the vertical direction (liquid flow direction) and 3.3 cm in the width direction, and only on the positive electrode side. Introduced. At this time, the number of sheets was adjusted so that the basis weight in the cell was 230 to 350 g / m 2 .
  • Two electrode materials prepared as described below were laminated on the negative electrode side to assemble the cell shown in FIG. A Nafion 212 membrane was used as the ion exchange membrane, and the spacer thickness was 0.5 mm.
  • the total cell resistance ( ⁇ ⁇ cm 2 ) was calculated from the voltage curve at the 10th cycle in the voltage range of 1.55 to 1.00 V at 144 mA / cm 2 by the following formula.
  • a 5.0 moL / L sulfuric acid aqueous solution in which titanium oxysulfate and manganese oxysulfate were dissolved at 1.0 moL / L was used for both the positive electrode and the negative electrode electrolytic solutions, and for the positive electrode and the negative electrode electrolytic solutions.
  • the amount of electrolyte was too large for the cell and piping.
  • the liquid flow rate was 10 mL per minute, and the measurement was performed at 35 ° C.
  • VC50 is the charge voltage obtained from the electrode curve with respect to the amount of electricity when the charge rate is 50%.
  • V D50 is the discharge voltage obtained from the electrode curve with respect to the amount of electricity when the charge rate is 50%.
  • I current density (mA / cm 2 )
  • a plain weave cloth (thickness 1.0 mm, basis weight 600 g / m 2 ) made of polyacrylonitrile fibers having an average fiber diameter of 16 ⁇ m was heated at 300 ° C. in an air atmosphere to make it flame resistant, and fired at 1000 ° C. for 1 hour in a nitrogen atmosphere. Then, it was heated at 600 ° C. for 8 minutes in an air atmosphere, and then calcined at 1800 ° C. for 1 hour in a nitrogen atmosphere. Further, the treatment was carried out at 700 ° C. for 15 minutes in an air atmosphere to obtain an electrode material for a negative electrode having a basis weight of 152 g / m 2 and a thickness of 0.73 mm.
  • Oxidation resistance test (-1) Oxidation resistance of carbon particles (including graphite particles) 1.0 moL / L Titanium oxysulfate in 5.0 moL / L sulfuric acid aqueous solution and 1.0 moL / L manganese oxysulfate
  • the carbon particles used in the examples were immersed in the above electrolytic solution in an amount 40 times the amount of the carbon particles, and allowed to stand at 75 ° C. for 16 hours.
  • the prepared electrode material was immersed in a charging liquid 40 times as much as the weight of the electrode, and allowed to stand at 75 ° C. for 16 hours. After allowing to cool to room temperature, the open circuit voltage of the electrolytic solution (platinum wire at the working electrode and Ag / AgCl at the reference electrode) was measured, and the oxidation resistance was estimated based on the degree of voltage drop from 1.266V.
  • Example 1 In this example, using various carbon particles (A to F, A', a, b) shown in Table 1, the particle size and Lc (B) are measured, and an oxidation resistance test is performed to perform oxidation resistance. Gender was evaluated.
  • a to D are graphites specified in the present invention
  • A, B and C are scaly graphites
  • D is flaky graphite.
  • E is scaly graphite having a small Lc
  • F is scaly graphite having a particle size of less than 1 ⁇ m and a small Lc.
  • A' is an example in which A is crushed by a bead mill for 6 hours with a Labostar mini machine manufactured by Ashizawa Finetech Co., Ltd., and Lc is small.
  • a and b are carbon black. Commercially available products are used for all the carbon particles, and the particle sizes shown in Table 1 are the values listed in the catalog. The particle size of A'was measured by laser diffraction.
  • Example 2 using some of the carbon particles in Table 1, an electrode material was prepared as follows and various items were measured.
  • Kao's Leodor TW-L120 nonionic surfactant
  • polyvinyl alcohol temporary adhesive
  • JFE Chemical's MCP250 carbonaceous material
  • Carbon paper (CFP-030-PE manufactured by Nippon Polymer Sangyo Co., Ltd., grain size 30 g / m 2 , thickness 0.51 mm) made of polyacrylonitrile fiber (average fiber diameter 10 ⁇ m) is immersed in the dispersion obtained in this manner. After that, the excess dispersion liquid was removed by passing it through a nip roller. Next, it was dried at 150 ° C. for 20 minutes in an air atmosphere, carbonized (calcined) at 1000 ° C. for 1 hour in a nitrogen atmosphere, and then graphitized at 2000 ° C. for 1 hour. After graphitization, no treatment was carried out in an air atmosphere, and an electrode material (No. 1) having a thickness of 0.50 mm and a basis weight of 134.0 g / m 2 was prepared.
  • an electrode material (No. 1) having a thickness of 0.50 mm and a basis weight of 134.0 g / m 2 was prepared.
  • Reference numeral 12 denotes a comparative example simulating the above-mentioned Patent Document 3, in which carbonaceous fibers were treated as follows without using graphite particles and a carbonaceous material to obtain an electrode material.
  • a marifleece woven fabric (thickness 0.81 mm, grain 100 g / m 2 ) made of flame-resistant polyacrylonitrile fiber was carbonized (baked) at 1000 ° C. for 1 hour in a nitrogen atmosphere, and then graphite was carbonized at 1500 ° C. for 1 hour. Then, it was oxidized at 700 ° C. for 15 minutes to obtain No.
  • An electrode material (comparative example) of 12 was prepared. The rate of temperature rise when the temperature is raised from the flame resistance temperature to the carbonization temperature is No. Same as 1.
  • No. 13 No. In No. 1, graphite particles were not used; except that a spunlace non-woven fabric carbonized at 1000 ° C. (grain 50 g / m 2 , thickness 0.85 mm) was used. No. 1 in the same manner as in 1. An electrode material (comparative example) of 13 (thickness 0.78 mm, basis weight 154.0 g / m 2 ) was prepared.
  • Table 2 shows the above No. The measurement results of various items in 1 to 13 are shown.
  • No. Nos. 1 to 7 are electrode materials satisfying the requirements of the present invention, and all of them have obtained electrode materials having excellent oxidation resistance while maintaining low resistance.
  • No. Comparative examples 8 to 13 are examples in which the amount of oxygen introduced was increased by performing dry air oxidation treatment in an air atmosphere after graphitization to increase the O / C to about 2 to 3%, and This is an example in which the BET specific surface area is also high.
  • No. Reference numeral 8 denotes an example in which a carbonaceous material having a low crystallinity of Lc (C) of 1.5 nm was used, and the oxidation resistance was lowered.
  • No. No. 9 except that the dry air oxidation treatment was not performed. No. which is the same as 9. In comparison with 2 (O / C ⁇ 1.0% of the present invention example), No. 9 is No. Compared with 2, the cell resistance was the same, but the oxidation resistance was lowered.
  • No. No. 10 except that the dry air oxidation treatment was not performed. No. which is the same as 10. In comparison with 3 (O / C ⁇ 1.0% of the present invention example), No. 10 is No. Compared with No. 3, the cell resistance was the same, but the oxidation resistance was lowered.
  • Reference numeral 12 denotes an example in which neither graphite particles nor carbonaceous materials were used in simulating Patent Document 3, and the cell resistance was high and the oxidation resistance was further lowered.
  • Reference numeral 13 denotes an example in which a highly crystalline carbonaceous material is used without using graphite particles and the BET specific surface area is low, and the oxidation resistance is excellent, but the cell resistance is the highest.
  • the present invention since it is possible to provide a carbon positive electrode material having low resistance and long life while maintaining high oxidation resistance, it is particularly useful as a positive electrode material for a redox flow battery using a manganese / titanium-based electrolytic solution. ..
  • the carbon positive electrode material of the present invention is suitably used for flow type and non-flow type redox flow batteries, redox flow batteries combined with lithium, capacitor, and fuel cell systems.

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Abstract

Le matériau d'électrode positive de carbone pour batterie redox à base de manganèse et titane de l'invention est constitué de fibres carbonées (A), de particules de graphite (B) et d'une matière carbonée (C) liant ceux-ci, et satisfait les conditions suivantes. (1) Le diamètre particulaire des particules de graphite (B) est supérieur ou égal à １μｍ ; (2) dans les particules de graphite (B), lorsque la taille de cristallite dans une direction axiale (c) obtenue par diffraction des rayons X est représentée par Ｌｃ（Ｂ）, alors Ｌｃ（Ｂ） est supérieure ou égale à 35nm ; (3) dans la matière carbonée (C), lorsque la taille de cristallite dans une direction axiale (c) obtenue par diffraction des rayons X est représentée par Ｌｃ（Ｃ）, alors Ｌｃ（Ｃ）est supérieure ou égale à 10nm ; (4) dans les fibres carbonées (A), lorsque la taille de cristallite dans une direction axiale (c) obtenue par diffraction des rayons X est représentée par Ｌｃ（A）, alors Ｌｃ（Ｃ）／Ｌｃ（Ａ） est supérieur ou égal à 1,0 ; (5) le nombre d'atomes d'oxygène liés à la surface du matériau d'électrode positive de carbone, est inférieur à 1,0% du nombre d'atomes de carbone total à la surface du matériau d'électrode positive de carbone ; enfin, (6) la surface spécifique BET obtenue à partir de la quantité d'adsorption d'azote, est comprise entre ０,５ et １,５ｍ2／ｇ.
PCT/JP2020/009754 2019-03-13 2020-03-06 Matériau d'électrode positive de carbone pour batterie redox à base de manganèse et titane, et batterie équipée de celui-ci WO2020184450A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59101776A (ja) * 1982-11-30 1984-06-12 Toyobo Co Ltd 電極材
JP2017033758A (ja) * 2015-07-31 2017-02-09 東洋紡株式会社 レドックス電池用炭素電極材
WO2019049755A1 (fr) * 2017-09-07 2019-03-14 東洋紡株式会社 Matériau d'électrode de carbone pour batterie redox et procédé de fabrication associé
WO2019049756A1 (fr) * 2017-09-07 2019-03-14 東洋紡株式会社 Matériau d'électrode de carbone pour batterie redox et procédé de fabrication associé

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59101776A (ja) * 1982-11-30 1984-06-12 Toyobo Co Ltd 電極材
JP2017033758A (ja) * 2015-07-31 2017-02-09 東洋紡株式会社 レドックス電池用炭素電極材
WO2019049755A1 (fr) * 2017-09-07 2019-03-14 東洋紡株式会社 Matériau d'électrode de carbone pour batterie redox et procédé de fabrication associé
WO2019049756A1 (fr) * 2017-09-07 2019-03-14 東洋紡株式会社 Matériau d'électrode de carbone pour batterie redox et procédé de fabrication associé

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