WO2021132400A1 - Cathode for producing electrolytic manganese dioxide - Google Patents

Cathode for producing electrolytic manganese dioxide Download PDF

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WO2021132400A1
WO2021132400A1 PCT/JP2020/048300 JP2020048300W WO2021132400A1 WO 2021132400 A1 WO2021132400 A1 WO 2021132400A1 JP 2020048300 W JP2020048300 W JP 2020048300W WO 2021132400 A1 WO2021132400 A1 WO 2021132400A1
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cathode
copper
manganese dioxide
electrolytic manganese
producing
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French (fr)
Japanese (ja)
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和正 末次
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東ソー株式会社
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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
    • C01B11/00—Oxides or oxyacids of halogens; Salts thereof
    • C01B11/12—Chloric acid
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/21—Manganese oxides
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/06—Electrodes for primary cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx

Definitions

  • the present invention relates to a cathode for producing electrolytic manganese dioxide, and more specifically, to a cathode used for producing electrolytic manganese dioxide used as a positive electrode active material in, for example, a manganese dry battery, particularly an alkaline manganese dry battery.
  • Electrolyzed manganese dioxide is known as, for example, a positive electrode active material for manganese dry batteries, particularly alkaline manganese dry batteries, and has the advantages of excellent storage stability and low cost.
  • alkaline manganese dry batteries that use electrolytic manganese dioxide as the positive electrode active material have excellent discharge characteristics at a wide range of discharge rates from low-rate discharge to high-rate discharge, so they are electronic devices, portable players, mobile information devices, and even games. Widely used in machines and toys, its demand is increasing not only in Japan but also in the world.
  • Electrolyzed manganese dioxide is generally produced by electrolytically oxidizing and precipitating on the anode by passing an electric current between the anode and the cathode in a sulfuric acid-acidic manganese sulfate electrolytic solution.
  • titanium or the like is used for the anode
  • graphite is mainly used for the cathode as the counter electrode, but copper or steel is used as a rare example (Patent Document 1).
  • the anode side where the electrolytic manganese dioxide precipitation reaction proceeds, does not directly affect the product quality on the cathode side, where the hydrogen generation reaction proceeds. There are few examples that have been examined in the past.
  • An object of the present invention is to provide a cathode modified for electrolytic manganese dioxide production, a cathode coated with a copper film along the surface shape of the cathode, and a method for producing the same.
  • the present inventor investigated the performance development and deterioration behavior of the cathode used in the production of electrolytic manganese dioxide, and as a result of diligent studies on the modification of the cathode, the cathode coated with a copper film along the surface shape of the cathode.
  • a cathode for producing electrolytic manganese dioxide which is composed of a graphite plate coated with a copper film.
  • a method for producing electrolytic manganese dioxide which comprises using the cathode for producing electrolytic manganese dioxide according to any one of the above [1] to [6].
  • a method for producing a positive electrode material for a battery which is synthesized by using electrolytic manganese dioxide produced by the method for producing electrolytic manganese dioxide described in the above [9].
  • the cathode for producing electrolytic manganese dioxide of the present invention can suppress deterioration of the cathode and maintain a low electrolytic voltage, so that efficient and stable production efficiency of electrolytic manganese dioxide can be exhibited.
  • the cathode for producing electrolytic manganese dioxide of the present invention is composed of a graphite plate coated with a copper film.
  • the graphite plate is mainly a plate shape that is also used for metal refining and plating, but it is not limited to this shape in essence.
  • paraffin when paraffin is contained inside the graphite plate, most of the paraffin is subjected to hot water cleaning treatment, organic solvent treatment, degreasing treatment using an alkaline solution, or combustion treatment. It is desirable to remove paraffin, at least in the vicinity of the surface to which the copper coating is later coated.
  • a degreasing detergent or the like mainly composed of an alkaline component may be used.
  • the copper film is a copper-based metal and its purity is not limited, but it is preferable that it contains 60 wt% or more of copper, and it is a composite film with a transition metal such as iron or nickel or a non-metal such as sulfur or phosphorus. Is also good.
  • the copper film exists on the graphite plate and acts as an electrode catalyst by maintaining its electrical contact. It is known that the catalytic activity of the hydrogen generating electrode of copper is superior to that of carbon, which is a material of graphite, in terms of basic chemistry (by UR EVANS, THE CORROSION AND OXIDATION OF METALS), for example, hydrogen. As an overvoltage, carbon has 0.7V, while copper has 0.53V, and it is said that it exhibits excellent activity at a low hydrogen overvoltage.
  • the thickness of the copper coating coated on the surface of the graphite plate is not limited, but is preferably 0.3 ⁇ m or more and 100 ⁇ m or less, more preferably 0.5 ⁇ m or more and 100 ⁇ m or less, and further preferably 0.5 ⁇ m or more and 50 ⁇ m. The following are most preferably selected from 1 ⁇ m or more and 20 ⁇ m or less.
  • the surface of the graphite plate may have irregularities of about several ⁇ m to several mm, and it is desirable that the irregularities on the surface of the graphite plate be completely covered by the copper film having the above-mentioned thickness, but it is not always completely covered.
  • At least copper may have a coating rate capable of exhibiting electrode catalytic activity, for example, a covering rate of 40%.
  • the portion of the graphite plate that is not immersed in the electrolytic solution, such as the feeding portion that supplies the current to the graphite plate, does not contribute to the electrode catalytic reaction, and therefore does not necessarily have to be covered with the copper film.
  • the cathode for producing electrolytic manganese dioxide of the present invention can be produced by coating a copper film by electroplating or electroless plating in an electrolytic solution containing copper ions using a graphite plate as a working electrode.
  • an electroplating method for example, an electroless plating method, or the like is used.
  • copper is coated by immersing a graphite plate in an electrolytic solution containing copper ions and passing an electric current between the graphite plate and the counter electrode (anode) for a predetermined time.
  • the electrolytic solution containing copper ions is prepared by dissolving a copper salt such as copper sulfate, copper hydrochloride, copper nitrate or copper pyrophosphate in the electrolytic solution.
  • a copper salt such as copper sulfate, copper hydrochloride, copper nitrate or copper pyrophosphate
  • a complexing agent such as citrate ion, tartrate ion, phosphate ion, pyrophosphate ion, a brightener typified by dextrin or lauryl sulfate ion, or thio. It may contain sulfur-containing substances such as urea.
  • the electrolytic solution containing copper ions may be mixed with transition metal ions such as iron ions and nickel ions as other metal ions to obtain a coating film of a copper-based alloy.
  • transition metal ions such as iron ions and nickel ions as other metal ions.
  • metal ions such as manganese ions that do not directly interact with copper ions and do not precipitate on the graphite plate are contained.
  • the pH of the electrolytic solution may be adjusted according to the properties of additives and metal ions contained in the electrolytic solution, but in the case of the present invention, the pH is generally 0.1 or more and pH 7 or less.
  • the copper ion concentration of the electrolytic solution is not particularly limited, but for example, 10 mg / L or more and 30 g / L or less is applied.
  • the electrolyte temperature is also not limited, but for example, 40 ° C. or higher and 98 ° C. or lower is applied.
  • Insoluble precious metals such as platinum and iridium are mainly used for the counter electrode (anode), but by controlling the concentration of components in the electrolytic solution, even metals with electrolytic dissolution such as copper should be used. Can be done.
  • the current applied during electrolysis is selected in the range of 20 A / m 2 or more and 1000 A / m 2 or less as the current density of the graphite plate, and electrolysis is continued until a predetermined copper film thickness is reached.
  • a reducing agent is added to an electrolytic solution containing copper ions, and a pretreated graphite plate is immersed for a predetermined time to be coated with copper.
  • the electrolytic solution containing copper ions is prepared by dissolving a copper salt such as copper sulfate, copper hydrochloride, copper nitrate or copper pyrophosphate in the electrolytic solution.
  • a copper salt such as copper sulfate, copper hydrochloride, copper nitrate or copper pyrophosphate
  • a complexing agent such as citrate ion, tartrate ion, phosphate ion, pyrophosphate ion, a polyacetylene glycol-based surfactant, or thiourea is typified. It may contain sulfur-containing substances and citric acid.
  • the electrolytic solution containing copper ions may be mixed with transition metal ions such as nickel ions as other metal ions to obtain a coating film of a copper-based alloy.
  • Sodium hypophosphate is typically used as the reducing agent.
  • the pH of the electrolytic solution is adjusted according to the properties of the additives and metal ions contained in the electrolytic solution, but in the case of the present invention, the pH is adjusted to be approximately pH 7 or more and pH 12 or less.
  • the copper ion concentration of the electrolytic solution is not particularly limited, but for example, 0.5 g / L or more and 30 g / L or less is applied.
  • the electrolyte temperature is also not limited, but for example, 20 ° C. or higher and 80 ° C. or lower is applied.
  • the bath load (V / A ratio of the area A (m 2 ) of the object to be plated to the volume V (m 3 ) of the electrolytic solution) in electroless plating is selected in the range of approximately 5 or more and 30 or less, and a predetermined copper coating is used. Immersion is continued until the thickness is reached.
  • pretreatment of the graphite plate in order to remove paraffin of the graphite plate, hot water cleaning treatment, organic solvent treatment, degreasing treatment using an alkaline solution, etc. are performed, or other metal is plated in advance as a base for copper coating. May be done.
  • a degreasing detergent or the like mainly composed of an alkaline component may be used.
  • a cathode base plate such as graphite is cut out so that a 1 cm square surface can be taken, so that the measurement direction is the only exposed surface, and a nickel lead wire is embedded in the back side of the cathode base plate so that electrical contact is maintained. It was embedded in (Technobit # 4071, manufactured by Marteau), and then the exposed surface was sanded with # 1500 sandpaper to prepare a cathode (electrode area 1 ⁇ 1 cm 2).
  • the exposed surface of the cathode was immersed in an electrolytic solution containing copper ions, and the copper film was coated by an electroplating method or a non-electrolytic plating method.
  • the exposed surface of the cathode or the cathode coated with a copper coating is immersed in a sulfuric acid solution at 96 ° C. and 28 g / L, and a platinum plate is used as the counter electrode and a saturated calomel electrode (SCE) is used as the reference electrode. It was connected to a galvanostat (HA-151B, manufactured by Hokuto Denko), and a current of 0.05 to 1 A / dm 2 was applied to S. C. It was measured by a method of reading the numerical value of the cathode potential with respect to the E reference electrode.
  • the cathode potential when a current of 0.5 A / dm 2 was applied was shown as a representative value of the cathode potential of each cathode.
  • the degree of potential change between 0.05 and 1 A / dm 2 is shown as a Tafel gradient (treated as an index of the electrochemical hydrogen generation mechanism of the electrode catalyst material).
  • a sulfuric acid-manganese sulfate mixed solution is used as the electrolytic solution, and a supplemented manganese sulfate solution having a manganese ion concentration of 46 g / L is continuously supplied into the electrolytic cell, and between the cathode or the cathode coated with a copper coating and the titanium anode.
  • An electrolysis test was carried out in which an electrolyzed manganese dioxide was deposited on the titanium anode by applying an electric current to the.
  • the electrolysis was performed for 18 days while adjusting the electrolysis current density to 0.68 A / dm 2 , the electrolysis temperature to 96 ° C, and the sulfuric acid concentration in the electrolytic cell to be 34 g / L.
  • a mercury / mercury sulfate electrode was used as a reference electrode, and the cathode potential was measured.
  • Comparative Example 1 A cathode was prepared using a graphite plate (PSG322, manufactured by SEC) in which paraffin was infiltrated at 24 mg / g, and the potential was measured. Cathode potential is -1.02 V vs. S. C. At E, the Tafel gradient was ⁇ 0.080 V / dec.
  • PSG322 graphite plate manufactured by SEC
  • Comparative Example 2 When the paraffin extraction and removal treatment with hexane was performed using the graphite plate of Comparative Example 1, the residual amount of paraffin was ⁇ 0.5 mg / g. A cathode was prepared from the graphite plate subjected to this paraffin removal treatment, and the potential was measured. Cathode potential is -0.70 V vs. S. C. It was E.
  • Comparative Example 3 When the paraffin removal treatment by combustion was performed using the graphite plate of Comparative Example 1, the residual amount of paraffin was ⁇ 0.5 mg / g. A cathode was prepared from the graphite plate subjected to this paraffin removal treatment, and the potential was measured. Cathode potential is -0.62V vs. S. C. At E, the Tafel gradient was -0.083V / dec. A photograph of the appearance of the obtained cathode is shown in FIG.
  • Example 1 A cathode prepared of a graphite plate subjected to the paraffin removal treatment of Comparative Example 3 was immersed in an electrolytic solution having copper (Cu 2+ ) ions of 10 g / L and a sulfuric acid concentration of 35 g / L, the counter electrode was a platinum plate, and the temperature was maintained at 70 ° C. While electroplating at a current density of 0.05 A / dm 2 for 50 minutes, a cathode was obtained. The cathode potential of the cathode after electroplating is -0.39 V vs. S. C. At E, the Tafel gradient was -0.060V / dec. A photograph of the appearance of the obtained cathode is shown in FIG. 2, and a photograph of a cross section near the surface is shown in FIG.
  • Example 1 electroplating was performed in the same manner as in Example 1 except that the electroplating conditions of current density and time were changed to obtain a cathode. Table 1 shows these electroplating conditions, the cathode potential of the cathode after electroplating, and the Tafel gradient values.
  • FIG. 4 A photograph of the appearance of the cathode obtained in Example 3 is shown in FIG. 4, and a photograph of the appearance of the cathode obtained in Example 4 is shown in FIG.
  • Example 5 Using a cathode prepared from a graphite plate subjected to the paraffin removal treatment of Comparative Example 3, copper (Cu 2+ ) ions were added to an aqueous solution having a manganese ion concentration of 27 g / L and a sulfuric acid concentration of 36 g / L so as to be 10 mg / L. The mixture was immersed in the electrolytic solution prepared by addition, the counter electrode was a platinum plate, the current density was 0.57 A / dm 2 , and the temperature was maintained at 96 ° C., and the mixture was energized for 60 minutes and electroplated to obtain a cathode.
  • the cathode potential of the cathode after electroplating is -0.47 V vs. S. C. It was E.
  • Example 5 electroplating was carried out in the same manner as in Example 5 except that the concentrations of copper (Cu 2+ ) ions added to the aqueous solution were 100 mg / L and 1000 mg / L to obtain a cathode. In both cases, it was confirmed that hydrogen gas bubbles were generated from the exposed surface of the cathode during electroplating, but after electroplating, the exposed surface of the cathode turned copper and it was visually observed that the copper film was coated. Table 1 shows these electroplating conditions and the values of the cathode potential of the cathode after electroplating. A photograph of the appearance of the cathode obtained in Example 7 is shown in FIG.
  • Example 8 The cathode prepared from the paraffin-removed graphite plate of Comparative Example 3 was prepared with copper (Cu 2+ ) ion 2 g / L, nickel (Ni 2+ ) ion 0.14 g / L, sodium citrate 13.5 g / L, and the following. Sodium citrate monohydrate 29 g / L, boric acid 31 g / L, and starch 0.4 g / L are immersed in an electrolytic solution under the condition of a bath load (V / A) of 10, the pH is set to 9.0, and the temperature is 60. Electrolyte-free plating was performed for 30 minutes while maintaining the temperature at ° C. to obtain a cathode.
  • V / A bath load
  • Example 9 Electrolytic plating was performed in the same manner as in Example 8 except that the pH of the electrolytic solution was set to 10.5 to obtain a cathode. As in Example 8, after electroless plating, the entire immersed portion of the cathode turned copper-colored, and it was visually observed that the copper film was coated. The cathode potential of the cathode measured after removing the other copper coating with sandpaper, leaving only the exposed surface of the cathode, was -0.47 V vs. S. C. At E, the Tafel gradient was ⁇ 0.059 V / dec. A photograph of the appearance of the obtained cathode is shown in FIG.
  • Comparative Example 4 A cathode was prepared using a copper plate instead of the graphite plate of Comparative Example 1, and the potential was measured. Cathode potential is -0.49 V vs. S. C. At E, the Tafel gradient was -0.062V / dec.
  • Comparative Example 5 A cathode was prepared using a nickel plate instead of the graphite plate of Comparative Example 1, and the potential was measured. Cathode potential is -0.59V vs. S. C. At E, the Tafel gradient was -0.077V / dec.
  • Comparative Example 6 A cathode was prepared using a platinum plate instead of the graphite plate of Comparative Example 1, and the potential was measured. Cathode potential is -0.35 V vs. S. C. At E, the Tafel gradient was -0.034V / dec.
  • FIG. 10 shows a Tafel plot showing the change between the logarithmic value of the current density and the potential when hydrogen is generated.
  • the cathode potential was improved by coating the graphite plate from which paraffin was removed with a copper thin film. Its characteristic level was superior to that of copper metal and close to that of platinum precious metal.
  • Example 10 A cathode was obtained in the same manner as in Example 8 except that electrolytic plating was performed for 60 minutes.
  • the obtained cathode was subjected to an electrolysis test according to ⁇ Electrolysis test method>.
  • the paraffin content of the obtained cathode was ⁇ 0.5 mg / g
  • the copper content was 1.88 mg / cm 2
  • the copper film thickness was 2.10 ⁇ m.
  • the cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is ⁇ 0.91 V vs. It was Hg 2 SO 4. These values are shown in Table 2.
  • Examples 11-14 A cathode was obtained in the same manner as in Example 10 except that the time for electroplating, the copper content, and the thickness of the copper coating were changed. The obtained cathode was subjected to an electrolysis test according to ⁇ Electrolysis test method>. These values are summarized in Table 2. In Examples 13 and 14, paraffin was detected from the cathode, and it was presumed that the paraffin re-permeated into the graphite substrate during electrolysis.
  • Comparative Example 7 An electrolysis test was carried out according to the ⁇ electrolysis test method> using the graphite plate subjected to the paraffin removal treatment of Comparative Example 3 as a cathode.
  • the paraffin content of this cathode was ⁇ 0.5 mg / g.
  • the cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is ⁇ 1.35 V vs. It was Hg 2 SO 4.
  • Comparative Example 8 An electrolysis test was carried out according to the ⁇ electrolysis test method> using a graphite plate (PSG322, manufactured by SEC) infiltrated with 54 mg / g of paraffin as a cathode.
  • the cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is -1.52 V vs. It was Hg 2 SO 4.
  • the cathode potential can be increased even in the electrolysis of electrolytic manganese dioxide precipitation using a sulfuric acid-manganese sulfate electrolytic solution. Improved. Its characteristic level was superior to that of copper metal, and it exhibited good performance even when paraffin re-penetrated into the graphite substrate during electrolysis.
  • Example 15 Using a graphite plate (PSG322, manufactured by SEC) infiltrated with 54 mg / g of paraffin, it was immersed in a degreasing detergent (SC-60, manufactured by Asahi Oleochemical) at 55 ° C. for 15 minutes, washed with water, and then electroplated by 60. A cathode was obtained in the same manner as in Example 8 except that it was carried out for a minute. The obtained cathode was subjected to an electrolysis test according to ⁇ Electrolysis test method>. The paraffin content of the obtained cathode was ⁇ 0.5 mg / g, and the copper film thickness was 1.8 ⁇ m. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is ⁇ 0.97 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
  • SC-60 degreasing detergent
  • Example 16 Using a graphite plate (PSG322, manufactured by SEC) infiltrated with 54 mg / g of paraffin, paraffin was removed by combustion, and then electroplating was performed in the same manner as in Example 1 to obtain a cathode.
  • the obtained cathode was subjected to an electrolysis test according to ⁇ Electrolysis test method>.
  • the paraffin content of the obtained cathode was ⁇ 0.5 mg / g, and the copper film thickness was 2.4 ⁇ m.
  • the cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is ⁇ 1.06 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
  • Example 17 Using a graphite plate (PSG322, manufactured by SEC) infiltrated with paraffin at 54 mg / g, it was immersed in a degreasing detergent (SC-60, manufactured by Asahi Oleochemical) at 55 ° C. for 15 minutes, washed with water, and then the same as in Example 16. Was electroplated to obtain a cathode.
  • the obtained cathode was subjected to an electrolysis test according to ⁇ Electrolysis test method>.
  • the paraffin content of the obtained cathode was ⁇ 0.5 mg / g, and the copper film thickness was 2.6 ⁇ m.
  • the cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is ⁇ 1.03 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
  • Example 18 Using a graphite plate (PSG322, manufactured by SEC) infiltrated with paraffin at 54 mg / g, electrolytic degreasing treatment was performed for 15 minutes with a degreasing detergent (SC-60, manufactured by Asahi Oleochemical) at 40 ° C., and after washing with water, Examples Electroplating was performed in the same manner as in No. 16 to obtain a cathode.
  • the obtained cathode was subjected to an electrolysis test according to ⁇ Electrolysis test method>.
  • the paraffin content of the obtained cathode was ⁇ 0.5 mg / g, and the copper film thickness was 3.0 ⁇ m.
  • the cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is ⁇ 1.07 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
  • a sulfuric acid-manganese sulfate electrolytic solution is obtained by coating a graphite plate on which a part of paraffin is removed using a commercially available degreasing cleaning agent with a copper thin film by either electroless plating or electroplating.
  • electrolysis of electrolytic manganese dioxide precipitation using the above the cathode potential was improved. Its characteristic level was as good as or better than that of copper metal.
  • the present invention is excellent in the activity of the hydrogen generation electrode catalytic reaction of the cathode and can maintain a low electrolytic voltage for a long period of time, so that electrolytic manganese dioxide can be stably produced at a low power intensity.

Abstract

Provided is a cathode for producing electrolytic manganese dioxide, the cathode being such that it is possible to suppress any deterioration in the cathode and to maintain a low electrolysis voltage, and being capable of realizing efficiency in the production of electrolytic manganese dioxide that is efficiently stabilized.　A cathode for producing electrolytic manganese dioxide, the cathode being characterized by being configured from graphite plates coated with copper coatings. Also, a method for producing a cathode for producing electrolytic manganese dioxide, the method being characterized in that a graphite plate is used as a working electrode, and a copper coating is formed by performing electroplating or electroless plating in a liquid electrolyte that contains copper ions.

Description

電解二酸化マンガン製造用陰極Cathode for electrolytic manganese dioxide production
　本発明は、電解二酸化マンガン製造用陰極に関するものであり、より詳しくは、例えば、マンガン乾電池、特にアルカリマンガン乾電池において、正極活物質として使用される電解二酸化マンガンの製造に用いる陰極に関する。 The present invention relates to a cathode for producing electrolytic manganese dioxide, and more specifically, to a cathode used for producing electrolytic manganese dioxide used as a positive electrode active material in, for example, a manganese dry battery, particularly an alkaline manganese dry battery.
　電解二酸化マンガンは、例えば、マンガン乾電池、特にアルカリマンガン乾電池の正極活物質として知られており、保存性に優れ、かつ安価であるという利点を有する。特に、電解二酸化マンガンを正極活物質として用いるアルカリマンガン乾電池は、ローレート放電からハイレート放電まで幅広い放電レートでの放電特性に優れていることから、電子機器、携帯用プレイヤー、携帯情報機器、さらにはゲーム機や玩具にまで幅広く使用され、日本だけでなく、世界でその需要が伸びてきている。 Electrolyzed manganese dioxide is known as, for example, a positive electrode active material for manganese dry batteries, particularly alkaline manganese dry batteries, and has the advantages of excellent storage stability and low cost. In particular, alkaline manganese dry batteries that use electrolytic manganese dioxide as the positive electrode active material have excellent discharge characteristics at a wide range of discharge rates from low-rate discharge to high-rate discharge, so they are electronic devices, portable players, mobile information devices, and even games. Widely used in machines and toys, its demand is increasing not only in Japan but also in the world.
　電解二酸化マンガンは、一般的に、硫酸酸性の硫酸マンガン電解液中で、陽極と陰極の間に電流を流すことにより、陽極上に電解酸化析出させて製造される。一般的に、陽極にはチタンなどが用いられ、対極である陰極には、主に黒鉛が用いられているが、希少例として銅や鋼が用いられる（特許文献１）。 Electrolyzed manganese dioxide is generally produced by electrolytically oxidizing and precipitating on the anode by passing an electric current between the anode and the cathode in a sulfuric acid-acidic manganese sulfate electrolytic solution. Generally, titanium or the like is used for the anode, and graphite is mainly used for the cathode as the counter electrode, but copper or steel is used as a rare example (Patent Document 1).
　電解二酸化マンガン製造時には、電解液の温度を９３℃～９８℃の高温で保つ必要があり、電解期間が１～４週間の長期に及ぶため、パラフィンなどの沸点が高い油層を電解液の上に浮かべ、電解液の蒸散を防ぐ対策がとられる。 When producing electrolytic manganese dioxide, it is necessary to keep the temperature of the electrolytic solution at a high temperature of 93 ° C to 98 ° C, and the electrolytic period is long for 1 to 4 weeks. Therefore, an oil layer having a high boiling point such as paraffin is placed on the electrolytic solution. Measures are taken to prevent floating and evaporation of the electrolyte.
　このパラフィンは、電解中だけでなく、電解終了後に電解二酸化マンガンが析出した陽極を電解槽から引き抜いてパラフィン油層を通過する際に、電解二酸化マンガン析出物に付着して取り込まれ、電解二酸化マンガンの製品品質に影響を与えるため、電解二酸化マンガンに取り込まれたパラフィンを熱湯洗浄で取り除いたり、あるいはパラフィンを極力取り込ませない工夫を施した電解方法が検討されている（特許文献２）。 This paraffin adheres to and is taken in by the electrolytic manganese dioxide precipitate not only during the electrolysis but also when the anode on which the electrolytic manganese dioxide is precipitated is pulled out from the electrolytic cell and passes through the paraffin oil layer after the electrolysis is completed. In order to affect the product quality, an electrolysis method has been studied in which the paraffin incorporated in the electrolytic manganese dioxide is removed by washing with boiling water, or the paralysis is not taken in as much as possible (Patent Document 2).
　一方で、このように電解二酸化マンガンの析出反応が進行する陽極側に対し、水素発生反応が進行する陰極側では、製品品質に直接影響を与えることはないので、これまであまり着目されることもなく、過去に検討された例も少ない。 On the other hand, the anode side, where the electrolytic manganese dioxide precipitation reaction proceeds, does not directly affect the product quality on the cathode side, where the hydrogen generation reaction proceeds. There are few examples that have been examined in the past.
　しかしながら、我々の検討によると、陰極に黒鉛を用いる場合、陰極が劣化し、結果として、電解二酸化マンガンの製造効率を著しく低下させる課題があることが判明した。 However, according to our study, it was found that when graphite is used as the cathode, the cathode deteriorates, and as a result, there is a problem that the production efficiency of electrolytic manganese dioxide is significantly reduced.
ＷＯ２０００／０３７７１４号公報WO2000 / 037714 日本国特開２００１－２４７９８７号公報Japanese Patent Application Laid-Open No. 2001-247987
　本発明の目的は、電解二酸化マンガン製造用に改質された陰極であり、陰極表面形状に沿って銅被膜を被覆した陰極、及びその製造方法を提供するものである。 An object of the present invention is to provide a cathode modified for electrolytic manganese dioxide production, a cathode coated with a copper film along the surface shape of the cathode, and a method for producing the same.
　本発明者は、電解二酸化マンガン製造に使用される陰極の性能発現と劣化の挙動について調査の上、陰極の改質について鋭意検討を重ねた結果、陰極表面形状に沿って銅被膜を被覆した陰極を用いることにより、陰極の劣化が抑制されるだけでなく、長期に亘って安定的に性能を維持でき、耐久性に優れることを見出して本発明を完成するに至ったものである。 The present inventor investigated the performance development and deterioration behavior of the cathode used in the production of electrolytic manganese dioxide, and as a result of diligent studies on the modification of the cathode, the cathode coated with a copper film along the surface shape of the cathode. By using the above, it has been found that not only the deterioration of the cathode is suppressed, but also the performance can be stably maintained for a long period of time and the durability is excellent, and the present invention has been completed.
　すなわち、本発明は以下の［１］乃至［１１］に存する。 That is, the present invention exists in the following [1] to [11].
　［１］　銅被膜が被覆された黒鉛板で構成されることを特徴とする電解二酸化マンガン製造用陰極。 [1] A cathode for producing electrolytic manganese dioxide, which is composed of a graphite plate coated with a copper film.
　［２］　銅被膜の厚みが０．３μｍ以上１００μｍ以下であることを特徴とする上記［１］に記載の電解二酸化マンガン製造用陰極。 [2] The cathode for producing electrolytic manganese dioxide according to the above [1], wherein the thickness of the copper film is 0.3 μm or more and 100 μm or less.
　［３］　銅被膜が銅を６０ｗｔ％以上含む銅基金属で構成されることを特徴とする上記［１］または［２］に記載の電解二酸化マンガン製造用陰極。 [3] The cathode for producing electrolytic manganese dioxide according to the above [1] or [2], wherein the copper coating is composed of a copper-based metal containing 60 wt% or more of copper.
　［４］　銅被膜が鉄またはニッケルなどの遷移元素を含む銅基金属で構成されることを特徴とする上記［１］～［３］のいずれかの項に記載の電解二酸化マンガン製造用陰極。 [4] The cathode for producing electrolytic manganese dioxide according to any one of the above [1] to [3], wherein the copper film is composed of a copper-based metal containing a transition element such as iron or nickel.
　［５］　銅被膜がリンまたはイオウを含む銅基金属で構成されることを特徴とする上記［１］～［４］のいずれかの項に記載の電解二酸化マンガン製造用陰極。 [5] The cathode for producing electrolytic manganese dioxide according to any one of the above [1] to [4], wherein the copper film is composed of a copper-based metal containing phosphorus or sulfur.
　［６］　黒鉛板がパラフィンを含むことを特徴とする上記［１］～［５］のいずれかの項に記載の電解二酸化マンガン製造用陰極。 [6] The cathode for producing electrolytic manganese dioxide according to any one of the above [1] to [5], wherein the graphite plate contains paraffin.
　［７］　黒鉛板を作用極として、銅イオンを含む電解液中で電気めっきして銅被膜を被覆することを特徴とする上記［１］～［６］のいずれかの項に記載の電解二酸化マンガン製造用陰極の製造方法。 [7] The electrolytic dioxide according to any one of the above [1] to [6], wherein the graphite plate is used as a working electrode and electroplated in an electrolytic solution containing copper ions to coat the copper film. A method for producing a cathode for manganese production.
　［８］　黒鉛板を作用極として、銅イオンを含む電解液中で無電解めっきして銅被膜を被覆することを特徴とする上記［１］～［６］のいずれかの項に記載の電解二酸化マンガン製造用陰極の製造方法。 [8] The electrolysis according to any one of the above [1] to [6], wherein a graphite plate is used as a working electrode and electroplating is performed in an electrolytic solution containing copper ions to coat a copper film. A method for producing a cathode for producing manganese dioxide.
　［９］　上記［１］～［６］のいずれかの項に記載の電解二酸化マンガン製造用陰極を用いることを特徴とする電解二酸化マンガンの製造方法。 [9] A method for producing electrolytic manganese dioxide, which comprises using the cathode for producing electrolytic manganese dioxide according to any one of the above [1] to [6].
　［１０］　上記［９］に記載された電解二酸化マンガンの製造方法で製造された電解二酸化マンガンを用いて合成されたことを特徴とする電池用正極材の製造方法。 [10] A method for producing a positive electrode material for a battery, which is synthesized by using electrolytic manganese dioxide produced by the method for producing electrolytic manganese dioxide described in the above [9].
　［１１］　上記［１０］に記載された電池用正極材を含有することを特徴とする電池。 [11] A battery characterized by containing the positive electrode material for a battery according to the above [10].
　本発明の電解二酸化マンガン製造用陰極は、陰極の劣化を抑制し、電解電圧を低く維持できるので、効率的で安定した電解二酸化マンガンの製造効率を発現できる。 The cathode for producing electrolytic manganese dioxide of the present invention can suppress deterioration of the cathode and maintain a low electrolytic voltage, so that efficient and stable production efficiency of electrolytic manganese dioxide can be exhibited.
比較例３で得られた陰極の外観写真である。It is a photograph of the appearance of the cathode obtained in Comparative Example 3. 実施例１で得られた陰極の外観写真である。It is a photograph of the appearance of the cathode obtained in Example 1. 実施例１で得られた陰極の表面近傍の断面写真である。It is a cross-sectional photograph of the vicinity of the surface of the cathode obtained in Example 1. 実施例３で得られた陰極の外観写真である。It is an appearance photograph of the cathode obtained in Example 3. 実施例４で得られた陰極の外観写真である。It is an appearance photograph of the cathode obtained in Example 4. 実施例７で得られた陰極の外観写真である。It is an appearance photograph of the cathode obtained in Example 7. 実施例８で得られた陰極の外観写真である。It is an appearance photograph of the cathode obtained in Example 8. 実施例９で得られた陰極の外観写真である。It is an appearance photograph of the cathode obtained in Example 9. 実施例１～４、実施例８、９と比較例４の、水素発生時における、電流密度の対数値と電位との変化を示すターフェルプロットである。9 is a Tafel plot showing changes in current density logarithmic value and potential during hydrogen generation in Examples 1 to 4, Examples 8 and 9, and Comparative Example 4. 比較例１、３～６の、水素発生時における、電流密度の対数値と電位との変化を示すターフェルプロットである。It is a Tafel plot which shows the change of the logarithmic value and the potential of the current density at the time of hydrogen generation in Comparative Examples 1, 3 to 6.
　以下に、本発明について詳細に説明する。 The present invention will be described in detail below.
　本発明の電解二酸化マンガン製造用陰極は、銅被膜が被覆された黒鉛板で構成されるものである。 The cathode for producing electrolytic manganese dioxide of the present invention is composed of a graphite plate coated with a copper film.
　黒鉛板は、金属精錬やめっきでも使用される板形状のものが主であるが、本質的にはこの形状に限るものではない。また、前述したように、黒鉛板内部にパラフィンが含まれている場合は、熱湯洗浄処理、有機溶剤処理、アルカリ液を用いた脱脂処理を施したり、または燃焼処理することによって、大部分のパラフィンを除去することが望ましく、少なくとも後に銅被膜が被覆される表面付近にはパラフィンが存在しないことが望ましい。工業的には、主にアルカリ成分で構成される脱脂洗浄剤などが用いられる場合がある。 The graphite plate is mainly a plate shape that is also used for metal refining and plating, but it is not limited to this shape in essence. In addition, as described above, when paraffin is contained inside the graphite plate, most of the paraffin is subjected to hot water cleaning treatment, organic solvent treatment, degreasing treatment using an alkaline solution, or combustion treatment. It is desirable to remove paraffin, at least in the vicinity of the surface to which the copper coating is later coated. Industrially, a degreasing detergent or the like mainly composed of an alkaline component may be used.
　銅被膜は銅基金属でありその純度について限定はないが、銅が６０ｗｔ％以上含まれることが好ましく、鉄やニッケルなどの遷移金属やイオウやリンなどの非金属などとの複合被膜であっても良い。 The copper film is a copper-based metal and its purity is not limited, but it is preferable that it contains 60 wt% or more of copper, and it is a composite film with a transition metal such as iron or nickel or a non-metal such as sulfur or phosphorus. Is also good.
　銅被膜は、黒鉛板上に存在してその電気的接触を保つことによって、電極触媒として作用する。銅の水素発生電極触媒活性は、基礎化学的にもグラファイトの素材であるカーボンよりも優れていることが知られており（Ｕ．Ｒ．ＥＶＡＮＳ著，ＴＨＥ　ＣＯＲＲＯＳＩＯＮ　ＡＮＤ　ＯＸＩＤＡＴＩＯＮ　ＯＦ　ＭＥＴＡＬＳ）、例えば、水素過電圧として、カーボンが０．７Ｖなのに対して、銅が０．５３Ｖとなり、低い水素過電圧で優れた活性を示すとされる。 The copper film exists on the graphite plate and acts as an electrode catalyst by maintaining its electrical contact. It is known that the catalytic activity of the hydrogen generating electrode of copper is superior to that of carbon, which is a material of graphite, in terms of basic chemistry (by UR EVANS, THE CORROSION AND OXIDATION OF METALS), for example, hydrogen. As an overvoltage, carbon has 0.7V, while copper has 0.53V, and it is said that it exhibits excellent activity at a low hydrogen overvoltage.
　黒鉛板表面上に被覆される銅被膜の厚みは限定されるものではないが、好ましくは０．３μｍ以上１００μｍ以下が、より好ましくは０．５μｍ以上１００μｍ以下が、さらに好ましくは０．５μｍ以上５０μｍ以下が、最も好ましくは１μｍ以上２０μｍ以下が選択される。黒鉛板表面には数μｍ～数ｍｍ程度の凹凸が存在する場合があり、この黒鉛板表面の凹凸は、前述した厚みの銅被膜によって全面的に覆われることが望ましいが、必ずしも完全に覆われる必要はなく、少なくとも銅が電極触媒活性を発現できる被覆率、例えば４０％の被覆率であっても良い。なお、黒鉛板に電流を供給する給電部など、電解液に浸漬されない黒鉛板の部分は、電極触媒反応には寄与しないので、必ずしも銅被膜に覆われる必要はない。 The thickness of the copper coating coated on the surface of the graphite plate is not limited, but is preferably 0.3 μm or more and 100 μm or less, more preferably 0.5 μm or more and 100 μm or less, and further preferably 0.5 μm or more and 50 μm. The following are most preferably selected from 1 μm or more and 20 μm or less. The surface of the graphite plate may have irregularities of about several μm to several mm, and it is desirable that the irregularities on the surface of the graphite plate be completely covered by the copper film having the above-mentioned thickness, but it is not always completely covered. It is not necessary, and at least copper may have a coating rate capable of exhibiting electrode catalytic activity, for example, a covering rate of 40%. The portion of the graphite plate that is not immersed in the electrolytic solution, such as the feeding portion that supplies the current to the graphite plate, does not contribute to the electrode catalytic reaction, and therefore does not necessarily have to be covered with the copper film.
　本発明の電解二酸化マンガン製造用陰極は、黒鉛板を作用極として、銅イオンを含む電解液中で電気めっき又は無電解めっきして銅被膜を被覆することで製造することができる。 The cathode for producing electrolytic manganese dioxide of the present invention can be produced by coating a copper film by electroplating or electroless plating in an electrolytic solution containing copper ions using a graphite plate as a working electrode.
　黒鉛板に銅被膜を被覆する方法としては、例えば、電気めっき法、無電解めっき法等が用いられる。 As a method of coating a graphite plate with a copper film, for example, an electroplating method, an electroless plating method, or the like is used.
　電気めっき法では、銅イオンを含む電解液に黒鉛板を浸し、黒鉛板と対極（陽極）との間に電流を所定時間流すことで銅が被覆される。 In the electroplating method, copper is coated by immersing a graphite plate in an electrolytic solution containing copper ions and passing an electric current between the graphite plate and the counter electrode (anode) for a predetermined time.
　銅イオンを含む電解液は、硫酸銅、塩酸銅、硝酸銅やピロリン酸銅などの銅塩を電解液に溶解させて調製する。電解液には、銅塩以外に、添加剤として、クエン酸イオン、酒石酸イオン、リン酸イオン、ピロリン酸イオンなどの錯化剤、またはデキストリンやラウリル硫酸イオンなどに代表される光沢剤、あるいはチオ尿素に代表されるイオウ含有物質などが含まれる場合がある。また、銅イオンを含む電解液には、他の金属イオンとして、鉄イオンやニッケルイオンなどの遷移金属イオンを混合して、銅基合金の被膜を得る場合もある。但し、マンガンイオンなど、銅イオンと直接的な相互作用がなく、黒鉛板に析出しない金属イオンが含まれていても問題ない。 The electrolytic solution containing copper ions is prepared by dissolving a copper salt such as copper sulfate, copper hydrochloride, copper nitrate or copper pyrophosphate in the electrolytic solution. In the electrolytic solution, in addition to the copper salt, as an additive, a complexing agent such as citrate ion, tartrate ion, phosphate ion, pyrophosphate ion, a brightener typified by dextrin or lauryl sulfate ion, or thio. It may contain sulfur-containing substances such as urea. Further, the electrolytic solution containing copper ions may be mixed with transition metal ions such as iron ions and nickel ions as other metal ions to obtain a coating film of a copper-based alloy. However, there is no problem even if metal ions such as manganese ions that do not directly interact with copper ions and do not precipitate on the graphite plate are contained.
　電解液のｐＨは、電解液中に含まれる添加剤や金属イオンの性質に応じて調整される場合があるが、本発明の場合、概ねｐＨ０．１以上ｐＨ７以下となる。 The pH of the electrolytic solution may be adjusted according to the properties of additives and metal ions contained in the electrolytic solution, but in the case of the present invention, the pH is generally 0.1 or more and pH 7 or less.
　電解液の銅イオン濃度は特に制限されるものではないが、例えば、１０ｍｇ／Ｌ以上３０ｇ／Ｌ以下が適用される。電解液温度も制限されるものではないが、例えば、４０℃以上９８℃以下が適用される。 The copper ion concentration of the electrolytic solution is not particularly limited, but for example, 10 mg / L or more and 30 g / L or less is applied. The electrolyte temperature is also not limited, but for example, 40 ° C. or higher and 98 ° C. or lower is applied.
　対極（陽極）には、主に、不溶性の白金やイリジウムなどの貴金属が用いられるが、電解液中の成分濃度を制御することによって、銅などの電解溶解を伴う金属であっても使用することができる。 Insoluble precious metals such as platinum and iridium are mainly used for the counter electrode (anode), but by controlling the concentration of components in the electrolytic solution, even metals with electrolytic dissolution such as copper should be used. Can be done.
　電解時に印加する電流としては、黒鉛板の電流密度として２０Ａ／ｍ２以上１０００Ａ／ｍ２以下の範囲で選択され、所定の銅被膜厚みになる時間まで電解が継続される。 The current applied during electrolysis is selected in the range of 20 A / m 2 or more and 1000 A / m 2 or less as the current density of the graphite plate, and electrolysis is continued until a predetermined copper film thickness is reached.
　無電解めっき法では、銅イオンを含む電解液に還元剤を添加し、前処理を施した黒鉛板を所定時間浸すことで銅被覆される。 In the electroless plating method, a reducing agent is added to an electrolytic solution containing copper ions, and a pretreated graphite plate is immersed for a predetermined time to be coated with copper.
　銅イオンを含む電解液は、硫酸銅、塩酸銅、硝酸銅やピロリン酸銅などの銅塩を電解液に溶解させて調製する。電解液には、銅塩以外に、添加剤として、クエン酸イオン、酒石酸イオン、リン酸イオン、ピロリン酸イオンなどの錯化剤、またはポリアセチレングリコール系の界面活性剤、あるいはチオ尿素に代表されるイオウ含有物質やホウ酸などが含まれる場合がある。また、銅イオンを含む電解液には、他の金属イオンとして、ニッケルイオンなどの遷移金属イオンを混合して、銅基合金の被膜を得る場合もある。 The electrolytic solution containing copper ions is prepared by dissolving a copper salt such as copper sulfate, copper hydrochloride, copper nitrate or copper pyrophosphate in the electrolytic solution. In the electrolytic solution, in addition to the copper salt, as an additive, a complexing agent such as citrate ion, tartrate ion, phosphate ion, pyrophosphate ion, a polyacetylene glycol-based surfactant, or thiourea is typified. It may contain sulfur-containing substances and citric acid. Further, the electrolytic solution containing copper ions may be mixed with transition metal ions such as nickel ions as other metal ions to obtain a coating film of a copper-based alloy.
　還元剤としては、代表的に次亜リン酸ナトリウムが使用される。 Sodium hypophosphate is typically used as the reducing agent.
　電解液のｐＨは、電解液中に含まれる添加剤や金属イオンの性質に応じて調整されるが、本発明の場合、概ねｐＨ７以上ｐＨ１２以下になるように調整される。 The pH of the electrolytic solution is adjusted according to the properties of the additives and metal ions contained in the electrolytic solution, but in the case of the present invention, the pH is adjusted to be approximately pH 7 or more and pH 12 or less.
　電解液の銅イオン濃度は特に制限されるものではないが、例えば、０．５ｇ／Ｌ以上３０ｇ／Ｌ以下が適用される。電解液温度も制限されるものではないが、例えば、２０℃以上８０℃以下が適用される。 The copper ion concentration of the electrolytic solution is not particularly limited, but for example, 0.5 g / L or more and 30 g / L or less is applied. The electrolyte temperature is also not limited, but for example, 20 ° C. or higher and 80 ° C. or lower is applied.
　無電解めっきにおける浴負荷（電解液の容積Ｖ（ｍ３）に対するめっき対象物の面積Ａ（ｍ２）のＶ／Ａ比率）は、概ね５以上３０以下の範囲で選択され、所定の銅被膜厚みになる時間まで浸漬が継続される。 The bath load (V / A ratio of the area A (m 2 ) of the object to be plated to the volume V (m 3 ) of the electrolytic solution) in electroless plating is selected in the range of approximately 5 or more and 30 or less, and a predetermined copper coating is used. Immersion is continued until the thickness is reached.
　黒鉛板の前処理としては、黒鉛板のパラフィンを除去するために、熱湯洗浄処理、有機溶剤処理、アルカリ液を用いた脱脂処理などが行われたり、あらかじめ銅被覆の下地として他の金属をめっきするなどが行われる場合がある。工業的には、黒鉛板のパラフィンを除去するために、主にアルカリ成分で構成される脱脂洗浄剤などが用いられる場合がある。 As pretreatment of the graphite plate, in order to remove paraffin of the graphite plate, hot water cleaning treatment, organic solvent treatment, degreasing treatment using an alkaline solution, etc. are performed, or other metal is plated in advance as a base for copper coating. May be done. Industrially, in order to remove paraffin on a graphite plate, a degreasing detergent or the like mainly composed of an alkaline component may be used.
　以下、本発明を実施例及び比較例により詳細に説明するが、本発明はこれら実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
　＜電位性能測定用の陰極作製方法＞
　黒鉛などの陰極基材板を１ｃｍ角の面がとれるように切出して、測定方向が唯一の露出面となるようにして、その裏側にニッケルリード線を埋め込み電気的接触を保った状態で硬化樹脂（テクノビット＃４０７１、マルトー製）に包埋させ、その後、露出面を＃１５００のサンドペーパーで研磨して、陰極（電極面積１×１ｃｍ２）を作製した。 <Cathode manufacturing method for measuring potential performance>
A cathode base plate such as graphite is cut out so that a 1 cm square surface can be taken, so that the measurement direction is the only exposed surface, and a nickel lead wire is embedded in the back side of the cathode base plate so that electrical contact is maintained. It was embedded in (Technobit # 4071, manufactured by Marteau), and then the exposed surface was sanded with # 1500 sandpaper to prepare a cathode (electrode area 1 × 1 cm 2).
　銅被膜を被覆した陰極を作製する場合は、陰極の露出面を銅イオンが含まれた電解液に浸し、電気めっき法または無電解めっき法にて銅被膜を被覆することによって得た。 When producing a cathode coated with a copper film, the exposed surface of the cathode was immersed in an electrolytic solution containing copper ions, and the copper film was coated by an electroplating method or a non-electrolytic plating method.
　＜電位性能測定＞
　陰極、または銅被膜が被覆された陰極の露出面を９６℃、２８ｇ／Ｌの硫酸液に浸して、対極には白金板、参照極として飽和カロメル電極（Ｓ．Ｃ．Ｅ）を用い、ポテンショガルバノスタット（ＨＡ－１５１Ｂ、北斗電工製）に接続し、０．０５～１Ａ／ｄｍ２の電流を印加して、Ｓ．Ｃ．Ｅ参照極に対する陰極電位の数値を読み取る方法で測定した。 <Measurement of potential performance>
The exposed surface of the cathode or the cathode coated with a copper coating is immersed in a sulfuric acid solution at 96 ° C. and 28 g / L, and a platinum plate is used as the counter electrode and a saturated calomel electrode (SCE) is used as the reference electrode. It was connected to a galvanostat (HA-151B, manufactured by Hokuto Denko), and a current of 0.05 to 1 A / dm 2 was applied to S. C. It was measured by a method of reading the numerical value of the cathode potential with respect to the E reference electrode.
　このうち、０．５Ａ／ｄｍ２の電流を印加した際の陰極電位を各陰極の陰極電位の代表値として示した。また、各陰極の他の性能指標として、０．０５～１Ａ／ｄｍ２間の電位変化度合いをターフェル勾配（電極触媒材料の電気化学的な水素発生機構の指標として扱われる）として示した。 Of these, the cathode potential when a current of 0.5 A / dm 2 was applied was shown as a representative value of the cathode potential of each cathode. In addition, as another performance index of each cathode, the degree of potential change between 0.05 and 1 A / dm 2 is shown as a Tafel gradient (treated as an index of the electrochemical hydrogen generation mechanism of the electrode catalyst material).
　＜電解試験方法＞
　電解液として硫酸－硫酸マンガン混合溶液を用い、マンガンイオン濃度４６ｇ／Ｌの補給硫酸マンガン液を電解槽内に連続的に供給しながら、陰極、または銅被膜が被覆された陰極とチタン陽極の間に電流を印加し、チタン陽極上に電解二酸化マンガンを析出させる電解試験を行った。この際、電解電流密度を０．６８Ａ／ｄｍ２、電解温度を９６℃とし、電解槽内の硫酸濃度が３４ｇ／Ｌとなるよう調整しながら１８日間電解した。電解中には、参照極として水銀／硫酸水銀電極を用い、陰極電位を測定した。 <Electrolysis test method>
A sulfuric acid-manganese sulfate mixed solution is used as the electrolytic solution, and a supplemented manganese sulfate solution having a manganese ion concentration of 46 g / L is continuously supplied into the electrolytic cell, and between the cathode or the cathode coated with a copper coating and the titanium anode. An electrolysis test was carried out in which an electrolyzed manganese dioxide was deposited on the titanium anode by applying an electric current to the. At this time, the electrolysis was performed for 18 days while adjusting the electrolysis current density to 0.68 A / dm 2 , the electrolysis temperature to 96 ° C, and the sulfuric acid concentration in the electrolytic cell to be 34 g / L. During electrolysis, a mercury / mercury sulfate electrode was used as a reference electrode, and the cathode potential was measured.
　比較例１
　パラフィンが２４ｍｇ／ｇ浸透した黒鉛板（ＰＳＧ３２２、ＳＥＣ製）を用いて、陰極を作製し、電位測定を行った。陰極電位は－１．０２Ｖ　ｖｓ.Ｓ．Ｃ．Ｅで、ターフェル勾配は、－０．０８０Ｖ／ｄｅｃであった。 Comparative Example 1
A cathode was prepared using a graphite plate (PSG322, manufactured by SEC) in which paraffin was infiltrated at 24 mg / g, and the potential was measured. Cathode potential is -1.02 V vs. S. C. At E, the Tafel gradient was −0.080 V / dec.
　比較例２
　比較例１の黒鉛板を用いて、ヘキサンによるパラフィン抽出除去処理を行ったところ、パラフィン残存量は＜０．５ｍｇ／ｇとなった。このパラフィン除去処理を行った黒鉛板で陰極を作製し、電位測定を行った。陰極電位は－０．７０Ｖ　ｖｓ．Ｓ．Ｃ．Ｅであった。 Comparative Example 2
When the paraffin extraction and removal treatment with hexane was performed using the graphite plate of Comparative Example 1, the residual amount of paraffin was <0.5 mg / g. A cathode was prepared from the graphite plate subjected to this paraffin removal treatment, and the potential was measured. Cathode potential is -0.70 V vs. S. C. It was E.
　比較例３
　比較例１の黒鉛板を用いて、燃焼によるパラフィン除去処理を行ったところ、パラフィン残存量は＜０．５ｍｇ／ｇとなった。このパラフィン除去処理を行った黒鉛板で陰極を作製し、電位測定を行った。陰極電位は－０．６２Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は、－０．０８３Ｖ／ｄｅｃであった。得られた陰極の外観写真を図１に示す。 Comparative Example 3
When the paraffin removal treatment by combustion was performed using the graphite plate of Comparative Example 1, the residual amount of paraffin was <0.5 mg / g. A cathode was prepared from the graphite plate subjected to this paraffin removal treatment, and the potential was measured. Cathode potential is -0.62V vs. S. C. At E, the Tafel gradient was -0.083V / dec. A photograph of the appearance of the obtained cathode is shown in FIG.
　実施例１
　比較例３のパラフィン除去処理を行った黒鉛板で作製した陰極を、銅（Ｃｕ２＋）イオン１０ｇ／Ｌ、硫酸濃度３５ｇ／Ｌの電解液に浸し、対極を白金板とし、温度７０℃に保ちながら、電流密度０．０５Ａ／ｄｍ２で５０分間電気めっきを行い、陰極を得た。電気めっき後の陰極の陰極電位は－０．３９Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は、－０．０６０Ｖ／ｄｅｃであった。得られた陰極の外観写真を図２に示し、表面近傍の断面写真を図３に示す。 Example 1
A cathode prepared of a graphite plate subjected to the paraffin removal treatment of Comparative Example 3 was immersed in an electrolytic solution having copper (Cu 2+ ) ions of 10 g / L and a sulfuric acid concentration of 35 g / L, the counter electrode was a platinum plate, and the temperature was maintained at 70 ° C. While electroplating at a current density of 0.05 A / dm 2 for 50 minutes, a cathode was obtained. The cathode potential of the cathode after electroplating is -0.39 V vs. S. C. At E, the Tafel gradient was -0.060V / dec. A photograph of the appearance of the obtained cathode is shown in FIG. 2, and a photograph of a cross section near the surface is shown in FIG.
　実施例２～４
　実施例１において、電流密度と時間の電気めっき条件を変えた以外は、実施例１と同様にして電気めっきを行い、陰極を得た。これらの電気めっき条件と電気めっき後の陰極の陰極電位、ターフェル勾配の値を表１に示した。 Examples 2-4
In Example 1, electroplating was performed in the same manner as in Example 1 except that the electroplating conditions of current density and time were changed to obtain a cathode. Table 1 shows these electroplating conditions, the cathode potential of the cathode after electroplating, and the Tafel gradient values.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例３で得られた陰極の外観写真を図４に示し、実施例４で得られた陰極の外観写真を図５に示す。 A photograph of the appearance of the cathode obtained in Example 3 is shown in FIG. 4, and a photograph of the appearance of the cathode obtained in Example 4 is shown in FIG.
　実施例５
　比較例３のパラフィン除去処理を行った黒鉛板で作製した陰極を用いて、マンガンイオン濃度２７ｇ／Ｌ、硫酸濃度３６ｇ／Ｌの水溶液に、銅（Ｃｕ２＋）イオンを１０ｍｇ／Ｌになるように添加して調製した電解液に浸し、対極を白金板とし、電流密度０．５７Ａ／ｄｍ２、温度９６℃に保ちながら、６０分間通電し、電気めっきを行い、陰極を得た。電気めっき中に陰極の露出面から水素ガスの気泡発生が確認されたが、電気めっき後には陰極の露出面は銅色に変わり、銅被膜が被覆されていることが目視された。電気めっき後の陰極の陰極電位は－０．４７Ｖ　ｖｓ．Ｓ．Ｃ．Ｅであった。 Example 5
Using a cathode prepared from a graphite plate subjected to the paraffin removal treatment of Comparative Example 3, copper (Cu 2+ ) ions were added to an aqueous solution having a manganese ion concentration of 27 g / L and a sulfuric acid concentration of 36 g / L so as to be 10 mg / L. The mixture was immersed in the electrolytic solution prepared by addition, the counter electrode was a platinum plate, the current density was 0.57 A / dm 2 , and the temperature was maintained at 96 ° C., and the mixture was energized for 60 minutes and electroplated to obtain a cathode. It was confirmed that hydrogen gas bubbles were generated from the exposed surface of the cathode during electroplating, but after electroplating, the exposed surface of the cathode turned copper and it was visually observed that the copper film was covered. The cathode potential of the cathode after electroplating is -0.47 V vs. S. C. It was E.
　実施例６～７
　実施例５において、水溶液に添加する銅（Ｃｕ２＋）イオンの濃度を１００ｍｇ／Ｌおよび１０００ｍｇ／Ｌとする以外は、実施例５と同様にして電気めっきを行い、陰極を得た。いずれも、電気めっき中に陰極の露出面から水素ガスの気泡発生が確認されたが、電気めっき後には陰極の露出面は銅色に変わり、銅被膜が被覆されていることが目視された。これらの電気めっき条件と電気めっき後の陰極の陰極電位の値を表１に示した。実施例７で得られた陰極の外観写真を図６に示す。 Examples 6-7
In Example 5, electroplating was carried out in the same manner as in Example 5 except that the concentrations of copper (Cu 2+ ) ions added to the aqueous solution were 100 mg / L and 1000 mg / L to obtain a cathode. In both cases, it was confirmed that hydrogen gas bubbles were generated from the exposed surface of the cathode during electroplating, but after electroplating, the exposed surface of the cathode turned copper and it was visually observed that the copper film was coated. Table 1 shows these electroplating conditions and the values of the cathode potential of the cathode after electroplating. A photograph of the appearance of the cathode obtained in Example 7 is shown in FIG.
　実施例８
　比較例３のパラフィン除去処理を行った黒鉛板で作製した陰極を、銅（Ｃｕ２＋）イオン２ｇ／Ｌ、ニッケル（Ｎｉ２＋）イオン０．１４ｇ／Ｌ、クエン酸ナトリウム１３．５ｇ／Ｌ、次亜リン酸ナトリウム・１水和物２９ｇ／Ｌ、ホウ酸３１ｇ／Ｌ、でんぷん０．４ｇ／Ｌの電解液に、浴負荷（Ｖ／Ａ）１０の条件で浸し、ｐＨ９．０として、温度６０℃に保ちながら、３０分間無電解めっきを行い、陰極を得た。無電解めっき後には、陰極の浸漬部全体が銅色に変わり、銅被膜が被覆されていることが目視された。陰極の露出面のみを残して他の銅被膜部分をサンドペーパーで除去した後に測定した陰極の陰極電位は－０．４６Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は－０．０５２Ｖ／ｄｅｃであった。得られた陰極の外観写真を図７に示す。 Example 8
The cathode prepared from the paraffin-removed graphite plate of Comparative Example 3 was prepared with copper (Cu 2+ ) ion 2 g / L, nickel (Ni 2+ ) ion 0.14 g / L, sodium citrate 13.5 g / L, and the following. Sodium citrate monohydrate 29 g / L, boric acid 31 g / L, and starch 0.4 g / L are immersed in an electrolytic solution under the condition of a bath load (V / A) of 10, the pH is set to 9.0, and the temperature is 60. Electrolyte-free plating was performed for 30 minutes while maintaining the temperature at ° C. to obtain a cathode. After electroless plating, the entire immersed portion of the cathode turned copper, and it was visually observed that the copper film was coated. The cathode potential of the cathode measured after removing the other copper coating with sandpaper, leaving only the exposed surface of the cathode, was -0.46 V vs. S. C. At E, the Tafel gradient was −0.052 V / dec. A photograph of the appearance of the obtained cathode is shown in FIG.
　実施例９
　電解液のｐＨを１０．５とした以外は実施例８と同様にして無電解めっきを行い、陰極を得た。実施例８と同じく、無電解めっき後には、陰極の浸漬部全体が銅色に変わり、銅被膜が被覆されていることが目視された。陰極の露出面のみを残して他の銅被膜部分をサンドペーパーで除去した後に測定した陰極の陰極電位は－０．４７Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は－０．０５９Ｖ／ｄｅｃであった。得られた陰極の外観写真を図８に示す。 Example 9
Electrolytic plating was performed in the same manner as in Example 8 except that the pH of the electrolytic solution was set to 10.5 to obtain a cathode. As in Example 8, after electroless plating, the entire immersed portion of the cathode turned copper-colored, and it was visually observed that the copper film was coated. The cathode potential of the cathode measured after removing the other copper coating with sandpaper, leaving only the exposed surface of the cathode, was -0.47 V vs. S. C. At E, the Tafel gradient was −0.059 V / dec. A photograph of the appearance of the obtained cathode is shown in FIG.
　比較例４
　比較例１の黒鉛板に代えて、銅板を用いて陰極を作製し、電位測定を行った。陰極電位は－０．４９Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は、－０．０６２Ｖ／ｄｅｃであった。 Comparative Example 4
A cathode was prepared using a copper plate instead of the graphite plate of Comparative Example 1, and the potential was measured. Cathode potential is -0.49 V vs. S. C. At E, the Tafel gradient was -0.062V / dec.
　比較例５
　比較例１の黒鉛板に代えて、ニッケル板を用いて陰極を作製し、電位測定を行った。陰極電位は－０．５９Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は、－０．０７７Ｖ／ｄｅｃであった。 Comparative Example 5
A cathode was prepared using a nickel plate instead of the graphite plate of Comparative Example 1, and the potential was measured. Cathode potential is -0.59V vs. S. C. At E, the Tafel gradient was -0.077V / dec.
　比較例６
　比較例１の黒鉛板に代えて、白金板を用いて陰極を作製し、電位測定を行った。陰極電位は－０．３５Ｖ　ｖｓ．Ｓ．Ｃ．Ｅで、ターフェル勾配は、－０．０３４Ｖ／ｄｅｃであった。 Comparative Example 6
A cathode was prepared using a platinum plate instead of the graphite plate of Comparative Example 1, and the potential was measured. Cathode potential is -0.35 V vs. S. C. At E, the Tafel gradient was -0.034V / dec.
　実施例１～４、実施例８、９と比較例４の、水素発生時における、電流密度の対数値と電位との変化を示すターフェルプロットを図９に示し、比較例１、３～６の、水素発生時における、電流密度の対数値と電位との変化を示すターフェルプロットを図１０に示す。 The Tafel plots of Examples 1 to 4, Examples 8 and 9 and Comparative Example 4 showing the changes in the logarithmic value of the current density and the potential during hydrogen generation are shown in FIG. FIG. 10 shows a Tafel plot showing the change between the logarithmic value of the current density and the potential when hydrogen is generated.
　以上のように、パラフィンを除去した黒鉛板に銅薄膜を被覆することにより、陰極電位が改善された。その特性レベルは、銅金属よりも優れ、白金貴金属に近いものであった。 As described above, the cathode potential was improved by coating the graphite plate from which paraffin was removed with a copper thin film. Its characteristic level was superior to that of copper metal and close to that of platinum precious metal.
　実施例１０
　無電解めっきを６０分間行った以外は実施例８と同様にして、陰極を得た。得られた陰極について、＜電解試験方法＞に従って電解試験を行った。得られた陰極のパラフィン含有量は＜０．５ｍｇ／ｇであり、銅含有量は１．８８ｍｇ／ｃｍ２で、銅被膜厚みは２．１０μｍであった。また、この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－０．９１Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。これらの数値を表２に示した。 Example 10
A cathode was obtained in the same manner as in Example 8 except that electrolytic plating was performed for 60 minutes. The obtained cathode was subjected to an electrolysis test according to <Electrolysis test method>. The paraffin content of the obtained cathode was <0.5 mg / g, the copper content was 1.88 mg / cm 2 , and the copper film thickness was 2.10 μm. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −0.91 V vs. It was Hg 2 SO 4. These values are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１１～１４
　無電解めっきの時間と銅含有量と銅被膜厚みを変更した以外は実施例１０と同様にして、陰極を得た。得られた陰極について、＜電解試験方法＞に従って電解試験を行った。これらの数値を表２にまとめて示した。なお、実施例１３、１４では、陰極からパラフィンが検出され、電解中にパラフィンがグラファイト基材へ再浸透したものと推定された。 Examples 11-14
A cathode was obtained in the same manner as in Example 10 except that the time for electroplating, the copper content, and the thickness of the copper coating were changed. The obtained cathode was subjected to an electrolysis test according to <Electrolysis test method>. These values are summarized in Table 2. In Examples 13 and 14, paraffin was detected from the cathode, and it was presumed that the paraffin re-permeated into the graphite substrate during electrolysis.
　比較例７
　比較例３のパラフィン除去処理を行った黒鉛板を陰極として、＜電解試験方法＞に従って電解試験を行った。この陰極のパラフィン含有量は＜０．５ｍｇ／ｇであった。また、この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－１．３５Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。 Comparative Example 7
An electrolysis test was carried out according to the <electrolysis test method> using the graphite plate subjected to the paraffin removal treatment of Comparative Example 3 as a cathode. The paraffin content of this cathode was <0.5 mg / g. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −1.35 V vs. It was Hg 2 SO 4.
　比較例８
　パラフィンが５４ｍｇ／ｇ浸透した黒鉛板（ＰＳＧ３２２、ＳＥＣ製）を陰極として、＜電解試験方法＞に従って電解試験を行った。この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－１．５２Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。 Comparative Example 8
An electrolysis test was carried out according to the <electrolysis test method> using a graphite plate (PSG322, manufactured by SEC) infiltrated with 54 mg / g of paraffin as a cathode. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is -1.52 V vs. It was Hg 2 SO 4.
　比較例９
　銅板を陰極として、＜電解試験方法＞に従って電解試験を行った。この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－１．０８Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。 Comparative Example 9
An electrolysis test was carried out according to the <electrolysis test method> using a copper plate as a cathode. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −1.08 V vs. It was Hg 2 SO 4.
　以上のように、燃焼法によりパラフィンを除去した黒鉛板に無電解銅めっき法で銅薄膜を被覆することにより、硫酸－硫酸マンガン電解液を用いた電解二酸化マンガン析出の電解においても、陰極電位が改善された。その特性レベルは、銅金属よりも優れ、電解中にグラファイト基材へパラフィンが再浸透しても良好な性能を発現した。 As described above, by coating the graphite plate from which paraffin has been removed by the combustion method with a copper thin film by the electroless copper plating method, the cathode potential can be increased even in the electrolysis of electrolytic manganese dioxide precipitation using a sulfuric acid-manganese sulfate electrolytic solution. Improved. Its characteristic level was superior to that of copper metal, and it exhibited good performance even when paraffin re-penetrated into the graphite substrate during electrolysis.
　実施例１５
　パラフィンが５４ｍｇ／ｇ浸透した黒鉛板（ＰＳＧ３２２、ＳＥＣ製）を用いて、５５℃の脱脂洗浄剤（ＳＣ－６０、旭油脂化学製）に１５分間浸漬し、水洗した後に、無電解めっきを６０分間行った以外は実施例８と同様にして、陰極を得た。得られた陰極について、＜電解試験方法＞に従って電解試験を行った。得られた陰極のパラフィン含有量は＜０．５ｍｇ／ｇであり、銅被膜厚みは１．８μｍであった。また、この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－０．９７Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。これらの数値を表３に示した。 Example 15
Using a graphite plate (PSG322, manufactured by SEC) infiltrated with 54 mg / g of paraffin, it was immersed in a degreasing detergent (SC-60, manufactured by Asahi Oleochemical) at 55 ° C. for 15 minutes, washed with water, and then electroplated by 60. A cathode was obtained in the same manner as in Example 8 except that it was carried out for a minute. The obtained cathode was subjected to an electrolysis test according to <Electrolysis test method>. The paraffin content of the obtained cathode was <0.5 mg / g, and the copper film thickness was 1.8 μm. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −0.97 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　実施例１６
　パラフィンが５４ｍｇ／ｇ浸透した黒鉛板（ＰＳＧ３２２、ＳＥＣ製）を用いて、燃焼によりパラフィン除去した後に、実施例１と同様に電気めっきを行い、陰極を得た。得られた陰極について、＜電解試験方法＞に従って電解試験を行った。得られた陰極のパラフィン含有量は＜０．５ｍｇ／ｇであり、銅被膜厚みは２．４μｍであった。また、この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－１．０６Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。これらの数値を表３に示した。 Example 16
Using a graphite plate (PSG322, manufactured by SEC) infiltrated with 54 mg / g of paraffin, paraffin was removed by combustion, and then electroplating was performed in the same manner as in Example 1 to obtain a cathode. The obtained cathode was subjected to an electrolysis test according to <Electrolysis test method>. The paraffin content of the obtained cathode was <0.5 mg / g, and the copper film thickness was 2.4 μm. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −1.06 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
　実施例１７
　パラフィンが５４ｍｇ／ｇ浸透した黒鉛板（ＰＳＧ３２２、ＳＥＣ製）を用いて、５５℃の脱脂洗浄剤（ＳＣ－６０、旭油脂化学製）に１５分間浸漬し、水洗した後に、実施例１６と同様に電気めっきを行い、陰極を得た。得られた陰極について、＜電解試験方法＞に従って電解試験を行った。得られた陰極のパラフィン含有量は＜０．５ｍｇ／ｇであり、銅被膜厚みは２．６μｍであった。また、この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－１．０３Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。これらの数値を表３に示した。 Example 17
Using a graphite plate (PSG322, manufactured by SEC) infiltrated with paraffin at 54 mg / g, it was immersed in a degreasing detergent (SC-60, manufactured by Asahi Oleochemical) at 55 ° C. for 15 minutes, washed with water, and then the same as in Example 16. Was electroplated to obtain a cathode. The obtained cathode was subjected to an electrolysis test according to <Electrolysis test method>. The paraffin content of the obtained cathode was <0.5 mg / g, and the copper film thickness was 2.6 μm. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −1.03 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
　実施例１８
　パラフィンが５４ｍｇ／ｇ浸透した黒鉛板（ＰＳＧ３２２、ＳＥＣ製）を用いて、４０℃の脱脂洗浄剤（ＳＣ－６０、旭油脂化学製）で１５分間電解脱脂処理を行い、水洗した後に、実施例１６と同様に電気めっきを行い、陰極を得た。得られた陰極について、＜電解試験方法＞に従って電解試験を行った。得られた陰極のパラフィン含有量は＜０．５ｍｇ／ｇであり、銅被膜厚みは３．０μｍであった。また、この陰極の硫酸／硫酸水銀参照極に対する陰極電位は、－１．０７Ｖ　ｖｓ．Ｈｇ２ＳＯ４であった。これらの数値を表３に示した。 Example 18
Using a graphite plate (PSG322, manufactured by SEC) infiltrated with paraffin at 54 mg / g, electrolytic degreasing treatment was performed for 15 minutes with a degreasing detergent (SC-60, manufactured by Asahi Oleochemical) at 40 ° C., and after washing with water, Examples Electroplating was performed in the same manner as in No. 16 to obtain a cathode. The obtained cathode was subjected to an electrolysis test according to <Electrolysis test method>. The paraffin content of the obtained cathode was <0.5 mg / g, and the copper film thickness was 3.0 μm. The cathode potential of this cathode with respect to the sulfuric acid / mercury sulfate reference electrode is −1.07 V vs. It was Hg 2 SO 4. These values are shown in Table 3.
　以上のように、パラフィンの一部を市販の脱脂洗浄剤を用いて除去した黒鉛板に、無電解めっき、電気めっきのいずれかの方法で銅薄膜を被覆することにより、硫酸－硫酸マンガン電解液を用いた電解二酸化マンガン析出の電解において、陰極電位が改善された。その特性レベルは、銅金属と同等以上の優れたものであった。 As described above, a sulfuric acid-manganese sulfate electrolytic solution is obtained by coating a graphite plate on which a part of paraffin is removed using a commercially available degreasing cleaning agent with a copper thin film by either electroless plating or electroplating. In the electrolysis of electrolytic manganese dioxide precipitation using the above, the cathode potential was improved. Its characteristic level was as good as or better than that of copper metal.
　なお、２０１９年１２月２７日に出願された日本特許出願２０１９－２３８０６８号及び２０２０年８月２６日に出願された日本特許出願２０２０－１４２５０８号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。 The specification, claims, drawings and abstracts of Japanese Patent Application No. 2019-238068 filed on December 27, 2019 and Japanese Patent Application No. 2020-142508 filed on August 26, 2020. The entire contents of the above are cited here and incorporated as disclosure of the specification of the present invention.
　本発明は、陰極の水素発生電極触媒反応の活性に優れ、長期に亘って低い電解電圧を維持できるため、低い電力原単位で安定して電解二酸化マンガンを製造できる。 The present invention is excellent in the activity of the hydrogen generation electrode catalytic reaction of the cathode and can maintain a low electrolytic voltage for a long period of time, so that electrolytic manganese dioxide can be stably produced at a low power intensity.
　１　黒鉛露出面
　２　包埋樹脂部
　３　銅被膜が被覆された黒鉛露出面
　４　包埋樹脂
　５　銅被膜
　６　黒鉛 1 Graphite exposed surface 2 Embedded resin part 3 Graphite exposed surface coated with copper coating 4 Embedded resin 5 Copper coating 6 Graphite

Claims (11)

  1. 銅被膜が被覆された黒鉛板で構成されることを特徴とする電解二酸化マンガン製造用陰極。 A cathode for producing electrolytic manganese dioxide, which is composed of a graphite plate coated with a copper film.
  2. 銅被膜の厚みが０．３μｍ以上１００μｍ以下であることを特徴とする請求項１に記載の電解二酸化マンガン製造用陰極。 The cathode for producing electrolytic manganese dioxide according to claim 1, wherein the thickness of the copper film is 0.3 μm or more and 100 μm or less.
  3. 銅被膜が銅を６０ｗｔ％以上含む銅基金属で構成されることを特徴とする請求項１または請求項２に記載の電解二酸化マンガン製造用陰極。 The cathode for producing electrolytic manganese dioxide according to claim 1 or 2, wherein the copper coating is composed of a copper-based metal containing 60 wt% or more of copper.
  4. 銅被膜が鉄またはニッケルなどの遷移元素を含む銅基金属で構成されることを特徴とする請求項１～請求項３のいずれかの項に記載の電解二酸化マンガン製造用陰極。 The cathode for producing electrolytic manganese dioxide according to any one of claims 1 to 3, wherein the copper film is composed of a copper-based metal containing a transition element such as iron or nickel.
  5. 銅被膜がリンまたはイオウを含む銅基金属で構成されることを特徴とする請求項１～請求項４のいずれかの項に記載の電解二酸化マンガン製造用陰極。 The cathode for producing electrolytic manganese dioxide according to any one of claims 1 to 4, wherein the copper coating is composed of a copper-based metal containing phosphorus or sulfur.
  6. 黒鉛板がパラフィンを含むことを特徴とする請求項１～請求項５のいずれかの項に記載の電解二酸化マンガン製造用陰極。 The cathode for producing electrolytic manganese dioxide according to any one of claims 1 to 5, wherein the graphite plate contains paraffin.
  7. 黒鉛板を作用極として、銅イオンを含む電解液中で電気めっきして銅被膜を被覆することを特徴とする請求項１～請求項６のいずれかの項に記載の電解二酸化マンガン製造用陰極の製造方法。 The cathode for producing electrolytic manganese dioxide according to any one of claims 1 to 6, wherein the graphite plate is used as a working electrode and electroplated in an electrolytic solution containing copper ions to coat the copper film. Manufacturing method.
  8. 黒鉛板を作用極として、銅イオンを含む電解液中で無電解めっきして銅被膜を被覆することを特徴とする請求項１～請求項６のいずれかの項に記載の電解二酸化マンガン製造用陰極の製造方法。 The electrolytic manganese dioxide production according to any one of claims 1 to 6, wherein the copper film is coated by electroless plating in an electrolytic solution containing copper ions using a graphite plate as a working electrode. Method for manufacturing cathode.
  9. 請求項１～請求項６のいずれかの項に記載の電解二酸化マンガン製造用陰極を用いることを特徴とする電解二酸化マンガンの製造方法。 A method for producing electrolytic manganese dioxide, which comprises using the cathode for producing electrolytic manganese dioxide according to any one of claims 1 to 6.
  10. 請求項９に記載された電解二酸化マンガンの製造方法で製造された電解二酸化マンガンを用いて合成されたことを特徴とする電池用正極材の製造方法。 A method for producing a positive electrode material for a battery, which is synthesized by using electrolytic manganese dioxide produced by the method for producing electrolytic manganese dioxide according to claim 9.
  11. 請求項１０に記載された電池用正極材を含有することを特徴とする電池。 A battery comprising the positive electrode material for a battery according to claim 10.
PCT/JP2020/048300 2019-12-27 2020-12-23 Cathode for producing electrolytic manganese dioxide WO2021132400A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60211086A (en) * 1984-02-27 1985-10-23 カ−マギ−　ケミカル　コ−ポレイシヨン Preparation of manganese dioxide
JPS6362893A (en) * 1986-09-04 1988-03-19 Tosoh Corp Cathode for producing electrolytic manganese dioxide
JPH01306591A (en) * 1988-06-03 1989-12-11 Kamioka Kogyo Kk Carbonaceous electrode and production thereof
JP2002533288A (en) * 1998-12-21 2002-10-08 カー−マックギー ケミカル エル．エル．スィー． Large discharge capacity electrolytic manganese dioxide and method for producing the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60211086A (en) * 1984-02-27 1985-10-23 カ−マギ−　ケミカル　コ−ポレイシヨン Preparation of manganese dioxide
JPS6362893A (en) * 1986-09-04 1988-03-19 Tosoh Corp Cathode for producing electrolytic manganese dioxide
JPH01306591A (en) * 1988-06-03 1989-12-11 Kamioka Kogyo Kk Carbonaceous electrode and production thereof
JP2002533288A (en) * 1998-12-21 2002-10-08 カー−マックギー ケミカル エル．エル．スィー． Large discharge capacity electrolytic manganese dioxide and method for producing the same

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