Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/24—Alkaline accumulators
• • 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
  • H01M4/24—Electrodes for alkaline accumulators
• • 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

Definitions

• An electrode active material for a secondary battery comprising a manganese oxide and a conductive additive, the conductive additive being present on at least a portion of a surface of the manganese oxide, and the conductive additive having a manganese/carbon area ratio of 0.30 or more and less than 1.00.
• the conductive assistant is acetylene black.
• This embodiment is an electrode active material for secondary batteries (hereinafter referred to as "this active material") that contains manganese oxide and a conductive additive, the mass ratio of the manganese oxide to the conductive additive is 90:10 to 99:1, the conductive additive is present on at least a portion of the manganese oxide surface, and the manganese/carbon area ratio (Mn/C area ratio) determined by EDS mapping is 0.30 or more and less than 1.0.
• this active material contains manganese oxide and a conductive additive
• the mass ratio of the manganese oxide to the conductive additive is 90:10 to 99:1
• the conductive additive is present on at least a portion of the manganese oxide surface
• the manganese/carbon area ratio (Mn/C area ratio) determined by EDS mapping is 0.30 or more and less than 1.0.
• the conductive additive contained in this active material may be at least one of crystalline carbon and amorphous carbon, for example, one or more selected from the group consisting of acetylene black, ketjen black, denka black, graphite, and carbon nanotubes, with acetylene black being preferred.
• the active material has a manganese/carbon area ratio (hereinafter simply referred to as "Mn/C area ratio") of the conductive additive determined by EDS mapping of 0.30 or more and less than 1.00.
• Mn/C area ratio manganese/carbon area ratio
• the Mn/C area ratio of the active material is preferably 0.30 or more, or preferably 0.40 or more, and preferably less than 1.00, or preferably 0.95 or less.
• Preferred Mn/C area ratios of the active material are 0.30 or more and less than 1.00, and 0.40 or more and 0.95 or less.
• the Mn/C area ratio in this embodiment can be determined by a cross-sectional view of the active material observed with a scanning electron microscope (hereinafter also referred to as "cross-sectional SEM") and an analysis using energy dispersive X-ray spectroscopy (hereinafter also referred to as "EDS"). That is, a cross-sectional SEM view of the active material, an EDS mapping view of manganese, and an EDS mapping view of carbon are obtained, and the Mn/C area ratio can be determined from these according to the following formula.
• Mn/C area ratio S Mn /S C
• S Mn is the area [ ⁇ m 2 ] of the manganese region corresponding to the active material in the manganese EDS mapping diagram
• S C is the area [ ⁇ m 2 ] of the carbon region corresponding to the active material in the carbon EDS mapping diagram.
• the area detected in the carbon mapping diagram corresponding to the present active material observed in the SEM observation diagram can be regarded as the carbon region
• the area SC calculated from the following formula can be regarded as the area of the carbon region of each particle.
• the cross-sectional SEM observation diagram and EDS mapping diagram may be observed and measured under the following conditions using a general cross-sectional SEM equipped with an EDS unit (for example, JSM-7600F, manufactured by JEOL Ltd.). Acceleration voltage: 5 kV Magnification: 500-10000x
• the manganese oxide content of this active material can be determined using a general potentiometric titrator (e.g., AT-610, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) according to a method conforming to JIS K 1467 5.2.
• a general potentiometric titrator e.g., AT-610, manufactured by Kyoto Electronics Manufacturing Co., Ltd.
• the mass proportion of the conductive additive is 0.100 mass% or more, or 1.00 mass% or more, and can be 30 mass% or less, or 25 mass% or less, with 0.100 mass% or more and 30 mass% or less, or 1.00 mass% or more and 25 mass% or less being preferred.
• a mixing method in the mixing process a mixing method using a device (e.g., Nobilta (registered trademark), manufactured by Hosokawa Micron) that mixes the manganese oxide and conductive additive while compressing, shearing, and impacting them with the force generated by the rotation of a rotor can be mentioned.
• a device e.g., Nobilta (registered trademark), manufactured by Hosokawa Micron
• the method for producing the active material may include at least one of a crushing step for crushing the active material and a classification step for classifying the active material after the mixing step.
• the crushing step is carried out for the purpose of crushing and dispersing the composite particles that have become coarse and aggregated after the mixing step.
• crushing using one or more mills selected from the group consisting of a pin mill, a jet mill, a hammer mill, and a ball mill can be used, with crushing using a pin mill being preferred.
• Classification is carried out for the purpose of making the particle size of the active material uniform, and examples of such classification include classification using one or more methods selected from the group consisting of sieves, air force, and solvents, with sieve classification being preferred.
• Mn/C area ratio The SEM observation diagrams and EDS mapping diagrams were observed and measured under the following conditions using an SEM (JSM-7600F, manufactured by JEOL Ltd.) equipped with an EDS unit. The Mn/C area ratio was calculated using the obtained EDS mapping diagrams by the method described above. Acceleration voltage: 5 kV Magnification: 2000x Mapping elements: Carbon, Manganese
• the clearance between the rotor and casing of the powder processing device was set to 3 mm, and the temperature of the cooling water flowing through the cooling jacket was set to 18°C.
• the electrolytic manganese dioxide and acetylene black described above were charged, and powder processing was carried out for 30 minutes while adjusting the rotation speed so that the load power was 1.8 kW to 2.2 kW to keep the compression pressure constant.
• the rotation speed was 5300 to 6100 rpm.
• the powder after processing was removed to obtain an active material containing electrolytic manganese dioxide and acetylene black, which was used as the active material of this example.
• the manganese oxide (electrolytic manganese dioxide) content in the active material of this example was 95% by mass.
• Mn/C area ratio of the active material of this example was 0.79, it was confirmed that acetylene black was present on the surface of the electrolytic manganese dioxide in a state of interaction. This improves the utilization rate of the active material of this example in the electrode, and further improves the filling property in the electrode, and is thought to improve cycle characteristics by suppressing excessive consumption of electrolyte.
• the present disclosure provides a manganese oxide-zinc-based secondary battery active material and a method for producing the same, which can produce a manganese oxide-zinc-based secondary battery with improved electrode active material utilization and cycle characteristics compared to conventional zinc-based secondary battery active materials.

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• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Battery Electrode And Active Subsutance (AREA)

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• 2024
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