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WO2021229802A1 - Method for producing carbon-coated lithium oxide and carbon-coated lithium oxide - Google Patents

Method for producing carbon-coated lithium oxide and carbon-coated lithium oxide Download PDF

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Publication number
WO2021229802A1
WO2021229802A1 PCT/JP2020/019458 JP2020019458W WO2021229802A1 WO 2021229802 A1 WO2021229802 A1 WO 2021229802A1 JP 2020019458 W JP2020019458 W JP 2020019458W WO 2021229802 A1 WO2021229802 A1 WO 2021229802A1
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Prior art keywords
carbon
lithium oxide
ball mill
wall surface
planetary ball
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PCT/JP2020/019458
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French (fr)
Japanese (ja)
Inventor
晃洋 鴻野
浩伸 蓑輪
正也 野原
武志 小松
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日本電信電話株式会社
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Priority to JP2022522477A priority Critical patent/JPWO2021229802A1/ja
Priority to PCT/JP2020/019458 priority patent/WO2021229802A1/en
Publication of WO2021229802A1 publication Critical patent/WO2021229802A1/en

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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
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/455—Phosphates containing halogen
    • 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
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • 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
    • 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
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a method for producing a carbon-coated lithium oxide and a carbon-coated lithium oxide.
  • Lithium-ion secondary batteries that use lithium-ion insertion and desorption reactions are widely used as secondary batteries with high energy density in various electronic devices, automobile power supplies, power storage, and the like. Research and development of electrode materials and electrolyte materials are underway for the purpose of improving the performance and reducing the cost (Non-Patent Document 1).
  • lithium secondary batteries have been attracting attention as mobile power sources.
  • batteries are required to be smaller and thinner, and battery materials are required to have even higher energy densities.
  • Non-Patent Document 1 focuses on Li2CoPO4F, which is a polyanionic positive electrode active material, as an example of a battery having a high voltage and a high energy density. Since Li2CoPO4F contains 2 atoms of Li per composition formula, it has a larger theoretical capacity (287 mgAh / g) as compared with LiCoPO4.
  • Li2CoPO4F has low ionic conductivity, it is necessary to impart electron conductivity by applying a carbon coating or the like in order to use it as a positive electrode active material. Since a large amount of carbon is required to maintain the electrical conductive path between the positive electrode active materials and to exhibit the desired conductivity, the ratio of the positive electrode active materials is relatively reduced, and the energy density is increased. It will be lowered.
  • the present invention has been made in view of this problem, and an object of the present invention is to provide a method for producing a carbon-coated lithium oxide having high conductivity, and a carbon-coated lithium oxide.
  • One aspect of the present invention is a method for producing a carbon-coated lithium oxide, which comprises a crushing step of crushing carbon with a crushing device, an adhesion step of adhering the crushed carbon to the container wall surface of the crushing device, and the container wall surface. Includes a coating step of coating the surface of the lithium oxide with the carbon adhering to the.
  • One aspect of the present invention is a carbon-coated lithium oxide, wherein the surface of the lithium oxide is coated with carbon, and the carbon is crushed by a crusher and adhered to the container wall surface of the crusher. ..
  • FIG. 1 is a flowchart showing a method for producing a carbon-coated lithium oxide according to an embodiment of the present invention.
  • the carbon-coated lithium oxide is a lithium oxide coated with carbon.
  • the manufacturing method of the present embodiment includes a pulverization step (step S1), an adhesion step (step S2), and a coating step (step S3).
  • the lithium oxide is imparted with electron conductivity by coating it with carbon.
  • the carbon may be composed of carbon, and the raw material is not particularly limited. Carbon includes, for example, at least one selected from the group consisting of carbon black, carbon nanotubes, fullerenes, graphene, graphite and amorphous carbon. In this embodiment, carbon black is used, but carbon black from any of the above groups may be used, or two or more types of carbon may be selected and mixed from the above group.
  • Li2CoPO4F for the lithium oxide, for example, Li2CoPO4F or the like can be used.
  • Li2CoPO4F is used as the lithium oxide, but the present invention is not limited to this.
  • each step is performed in an inert gas.
  • each step is carried out in a nitrogen atmosphere, but any inert gas may be used, and for example, argon, helium or the like can be used. Further, the same effect can be obtained in air, but a part of carbon chemically reacts with oxygen during each process to become carbon dioxide, so that the yield of carbon-coated lithium oxide decreases. ..
  • the above-mentioned carbon is crushed by a crushing device (step S1).
  • the crushing process uses, for example, a crushing device such as a mixer, a homogenizer, an ultrasonic homogenizer, a high-speed rotary shear type stirrer, a colloidal mill, a roll mill, a high-pressure injection disperser, a rotary ball mill, a vibration ball mill, a planetary ball mill, and an attritor. And powder the carbon.
  • the crushed carbon preferably has a secondary particle size of 1 nm to 1 ⁇ m, and more preferably 1 nm to 0.5 ⁇ m.
  • the particle size of lithium oxide used in a lithium secondary battery is 1 ⁇ m to 10 ⁇ m, and in order to adhere carbon to the particles of lithium oxide for coating, the particle size of carbon is at most lithium. This is because it is desirable that the particle size of the oxide is 1/20 or less. Needless to say, the smaller the grain size of carbon, the lower the porosity between carbons, and the higher the density of carbon, which improves the conductive path.
  • carbon is crushed using a planetary ball mill.
  • the manufacturing method using a planetary ball mill is preferable as a method for atomizing particles because a strong centrifugal force can be applied to the particles.
  • FIG. 2 shows an external view of the jar 1 (container) of the planetary ball mill.
  • the inside of the jar 1 is hollow and has a wall surface 2.
  • carbon and zirconia beads are placed in the jar 1 and the jar 1 is rotated and revolved to crush the carbon.
  • the rotation ratio is 1: -2.
  • the rotation ratio was set to 1: -2.
  • the revolution speed of the container of the planetary ball mill in the crushing step is preferably 100 rpm or more.
  • the revolution speed is preferably 100 rpm or more.
  • carbon can be pulverized, and after undergoing a coating step described later, electrical conductivity can be imparted to the lithium oxide.
  • the revolution speed is 300 rpm or more, carbon can be atomized, which is more preferable.
  • the revolution speed is less than 100 rpm, the carbon cannot be pulverized, and the lithium oxide cannot be imparted with electrical conductivity after undergoing the coating step described later.
  • carbon when carbon is crushed alone, carbon may be impregnated with an organic solvent and then crushed in order to prevent the carbon powder from flying during or after crushing.
  • the organic solvent used here is not particularly limited.
  • examples of the organic solvent include 3-methyl-3-methoxybutyl ether, 3-methyl-3-methoxybutanol, n-butanol, n-butylamine, n-methylpyrrolidone, acetone, isoamyl alcohol, isobutanol, isopropanol, ethanol, and the like.
  • Ethylcarbitol ethylene glycol, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether, octanol, carboxylic acid, diethylene glycol methyl ether, dipropylene glycol isopropyl ethyl ether, dipropylene glycol isopropylmethyl ether, dipropylene glycol ethyl ether, dipropylene glycol methyl At least one selected from the group consisting of ether, dodecane, tripropylene glycol methyl ether, propanol, propylene glycol ethyl ether acetate, propylene monomethyl ether, hexadecane, heptane, methanol, butyl acetate, butyl lactate, unsaturated fatty acid, and glycerin. Can be used.
  • a drying step may be performed after the coating step (step S3).
  • the solvent is removed by drying the lithium oxide coated with the carbon containing the solvent in a constant temperature bath, a dryer, natural drying or the like. If the solvent can be removed, the drying temperature is not particularly limited, but the drying time can be shortened by heating at a temperature equal to or lower than the boiling point, the flash point, and the ignition point of the solvent to be used.
  • the crushed carbon is attached to the container wall surface of the crusher (step S2).
  • the adhesion step is a step of adhering carbon to the wall surface of the mixing container at high density.
  • a high-pressure injection type disperser for example, a rotary ball mill, a vibrating ball mill, a planetary ball mill, an attritor, a kneader, or the like can be used.
  • carbon is attached to the wall surface 2 of the jar 1 (container) by using the planetary ball mill (crushing device) used in the crushing step.
  • the manufacturing method using a planetary ball mill is preferable because a strong centrifugal force 6 can be applied to the particles and the wall surface 2.
  • FIG. 3 shows an enlarged view of the jar wall surface 2 in the attachment process.
  • carbon 4 carbon particles
  • the carbon 4 adheres to the jar wall surface 2 due to the centrifugal force 6, and the carbon 4A (carbon film, carbon layer) is attached to the jar wall surface 2. Is formed.
  • the revolution speed of the jar 1 is 300 rpm or more
  • the carbon 4 can be attached to the jar wall surface 2.
  • the revolution speed of the jar 1 of the planetary ball mill in the attachment step is preferably 300 rpm or more. The higher the revolution speed, the stronger centrifugal force can be applied to the carbon 4 and the jar wall surface 2, and the rotation time can be shortened. Further, the higher the revolution speed, the higher the density of the carbon film 4A can be formed on the jar wall surface 2.
  • the carbon 4 cannot adhere to the jar wall surface 2, but if the revolution speed is 300 rpm or more in the next coating step, the carbon 4 adheres to the jar wall surface and lithium oxide.
  • the coating is done at the same time.
  • FIG. 4 shows an external view of the jar 1 of the planetary ball mill after the attachment process. As shown in the figure, a carbon film 4A is formed on the wall surface of the jar.
  • the carbon adhering to the wall surface of the container is coated on the surface of the lithium oxide (step S3).
  • the coating step is a step of coating the lithium oxide with the carbon 4A produced on the jar wall surface 2 in the bonding step.
  • the lithium oxide is charged into the planetary ball mill (crushing device) used in the crushing step and the bonding step, and the carbon adhering to the jar wall surface 2 is coated with the lithium oxide.
  • carbon is attached to the lithium oxide by strongly contacting the lithium oxide with the carbon using, for example, zirconia beads.
  • FIG. 5 shows an enlarged view of the jar wall surface 2 in the covering process.
  • the lithium oxide 7 is present between the zirconia beads 3 and the jar wall surface 2
  • the carbon 4A adhering to the jar wall surface 2 is coated on the lithium oxide 7 by the centrifugal force 6, and the lithium oxide is coated with the carbon 4A.
  • Oxide 7 is formed.
  • FIG. 6 is an enlarged view of the lithium oxide 7 before and after the coating process.
  • the revolution speed of the jar 1 is 300 rpm or more
  • high-density carbon 4A can be attached to the lithium oxide 7.
  • the revolution speed of the jar 1 of the planetary ball mill in the covering step is preferably 300 rpm or more.
  • the higher the revolution speed the stronger centrifugal force can be applied to the carbon 4A and the lithium oxide 7, and the rotation time can be shortened. Further, as the revolution speed is higher, the lithium oxide 7 can be coated with a smaller amount of carbon. Therefore, it is possible to produce a carbon-coated lithium oxide having high conductivity.
  • revolution speed is less than 300 rpm, carbon 4A cannot be attached to the lithium oxide 7, but if the revolution speed is 300 rpm or more in the previous attachment step, it adheres to the jar wall surface and lithium oxide.
  • the covering of the object is performed at the same time.
  • the method for producing the carbon-coated lithium oxide of the present embodiment includes a crushing step of crushing carbon with a crushing device, an adhesion step of adhering the crushed carbon to the container wall surface of the crushing device, and the container. It includes a coating step of coating the surface of the lithium oxide with carbon adhering to the wall surface.
  • the carbon-coated lithium oxide of the present embodiment is carbon in which the surface of the lithium oxide is coated with carbon, the carbon is crushed by a crushing device, and the carbon is adhered to the container wall surface of the crushing device.
  • the carbon-coated lithium oxide (Experimental Example 1-4) produced by the production method of the present embodiment is produced by a production method different from that of the present embodiment.
  • An experiment was carried out with a carbon-coated lithium oxide (comparative example).
  • Li2CoPO4F which is a polyanionic positive electrode active material, was used as the lithium oxide.
  • Example 1 In Experimental Example 1, in the crushing step, zirconia balls having a diameter of 2 mm and zirconia balls having a diameter of 1 mm were put into a planetary ball mill (model number: PM100) manufactured by Retsch at a ratio of 1: 1 and mixed with Ketjen black (carbon). bottom. The planetary ball mill was rotated at 100 rpm for 1 hour to crush Ketjen black. When Ketjen Black, which had been rotated for 1 hour at a revolution speed of 50 rpm of the planetary ball mill, was sieved, Ketjen Black was not crushed and remained on the sieve.
  • a planetary ball mill model number: PM100
  • Ketjen Black which had been rotated for 1 hour at a revolution speed of 50 rpm of the planetary ball mill
  • the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 100 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface.
  • lithium oxide Li2CoPO4F
  • the revolution speed of the planetary ball mill was set to 100 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
  • Example 2 In Experimental Example 2, the same crushing step as in Experimental Example 1 was performed to crush Ketjen Black.
  • the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 100 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface.
  • lithium oxide Li2CoPO4F
  • the revolution speed of the planetary ball mill was set to 300 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
  • Example 3 In Experimental Example 3, the same crushing step as in Experimental Example 1 was performed to crush Ketjen Black.
  • the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 300 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface.
  • lithium oxide Li2CoPO4F
  • the revolution speed of the planetary ball mill was set to 100 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
  • Example 4 In Experimental Example 4, the same crushing step as in Experimental Example 1 was performed to crush Ketjen Black.
  • the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 300 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface.
  • lithium oxide Li2CoPO4F
  • the revolution speed of the planetary ball mill was set to 300 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
  • Li2CoPO4F which is a lithium oxide
  • Ketjen Black which is carbon
  • the resistivity of Experimental Example 1 is 2, and the resistivity of Experimental Example 2-4 is 1.
  • the resistivity of the comparative example is 10. That is, it was confirmed that the resistivity of Experimental Example 1-4 of this embodiment was lower than that of Comparative Example. Therefore, the carbon-coated lithium oxide of Experimental Example 1-4 has higher conductivity than the carbon-coated lithium oxide of Comparative Example, and can realize a lithium battery having a high energy density.
  • the resistivity of Experimental Examples 2 and 3 in which the number of revolutions of the adhesion step or the coating step is 300 rpm and the resistivity of Experimental Example 4 in which the number of revolutions of the adhesion step and the coating step is 300 rpm is 1.
  • the resistivity of Experimental Example 1 in which the number of revolutions of the adhesion step and the coating step is 100 rpm is 2. This is a positive electrode active material because when the revolution speeds of both the adhesion process and the coating process are low, the pressure applied to the zirconia ball and the container wall surface is low, and the carbon surface is not coated with a high-density film. It is considered that the formation of conductive paths between lithium oxides is insufficient.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The purpose of the present invention is to provide a method for producing a highly electroconductive carbon-coated lithium oxide, and a carbon-coated lithium oxide.　One embodiment according to the present invention is a method for producing a carbon-coated lithium oxide. The method comprises a crushing step (S1) for crushing carbon with a crushing machine, an adhering step (S2) for adhering the crushed carbon to a wall surface of a container of the crushing machine, and a coating step (S3) for coating a surface of a lithium oxide with the carbon adhering to the wall surface.

Description

カーボン被覆リチウム酸化物の製造方法、および、カーボン被覆リチウム酸化物Manufacturing method of carbon-coated lithium oxide and carbon-coated lithium oxide
　本発明は、カーボン被覆リチウム酸化物の製造方法、および、カーボン被覆リチウム酸化物に関する。 The present invention relates to a method for producing a carbon-coated lithium oxide and a carbon-coated lithium oxide.
　リチウムイオンの挿入および脱離反応を用いるリチウムイオン二次電池は、エネルギー密度の高い二次電池として様々な電子機器、自動車用電源、及び電力貯蔵等の用途で広く使用されている。その性能向上及び低コスト化を目的に、電極材料及び電解質材料の研究開発が進められている（非特許文献１）。 Lithium-ion secondary batteries that use lithium-ion insertion and desorption reactions are widely used as secondary batteries with high energy density in various electronic devices, automobile power supplies, power storage, and the like. Research and development of electrode materials and electrolyte materials are underway for the purpose of improving the performance and reducing the cost (Non-Patent Document 1).
　近頃では、スマートフォン等のＩＴ機器及びＩｏＴ機器の発展により、モバイル電源用としてリチウム二次電池が注目されている。モバイル機器の小型化にともない、電池の小型化・薄型も求められ、より一層の高エネルギー密度化が電池材料に求められている。 Recently, with the development of IT devices such as smartphones and IoT devices, lithium secondary batteries have been attracting attention as mobile power sources. As mobile devices become smaller, batteries are required to be smaller and thinner, and battery materials are required to have even higher energy densities.
　非特許文献１では、電圧が高くエネルギー密度の高い電池の例としてポリアニオン系正極活物質であるＬｉ２ＣｏＰＯ４Ｆに着目している。Ｌｉ２ＣｏＰＯ４Ｆは、組成式あたりＬｉを２原子含むことから、ＬｉＣｏＰＯ４と比較して、より大きな理論容量（２８７ｍｇＡｈ／ｇ）を有している。 Non-Patent Document 1 focuses on Li2CoPO4F, which is a polyanionic positive electrode active material, as an example of a battery having a high voltage and a high energy density. Since Li2CoPO4F contains 2 atoms of Li per composition formula, it has a larger theoretical capacity (287 mgAh / g) as compared with LiCoPO4.
　しかしながら、Ｌｉ２ＣｏＰＯ４Ｆは、イオン電導性が低いため、正極活物質として用いるには、カーボンコーティングなどを行うことにより、電子伝導性を付与することが必要である。正極活物質同士の電気的な導電パスを維持し、所望の導電性を発揮するには大量のカーボンが必要になるため、相対的に正極活物質の割合が低下することになり、エネルギー密度を下げてしまうことになる。 However, since Li2CoPO4F has low ionic conductivity, it is necessary to impart electron conductivity by applying a carbon coating or the like in order to use it as a positive electrode active material. Since a large amount of carbon is required to maintain the electrical conductive path between the positive electrode active materials and to exhibit the desired conductivity, the ratio of the positive electrode active materials is relatively reduced, and the energy density is increased. It will be lowered.
　カーボンの量を減らしつつ、所望の導電性を発揮するためには、正極活物質とカーボンの導電パスおよびカーボン同士の導電パスが繋がっていることが必要であり、特に、正極活物質とカーボンの密着性を高くすることが必要となる。したがって、少量のカーボンを用いて、導電性が高い、カーボンが被覆されたリチウム酸化物を得ることは、高エネルギー密度な電池を作製するうえで重要な課題である。 In order to exhibit the desired conductivity while reducing the amount of carbon, it is necessary that the positive electrode active material and the conductive path of carbon and the conductive path between carbons are connected, and in particular, the positive electrode active material and carbon It is necessary to increase the adhesion. Therefore, obtaining a highly conductive, carbon-coated lithium oxide using a small amount of carbon is an important issue in producing a battery having a high energy density.
　本発明は、この課題に鑑みてなされたものであり、導電性が高い、カーボン被覆リチウム酸化物の製造方法、および、カーボン被覆リチウム酸化物を提供することを目的とする。 The present invention has been made in view of this problem, and an object of the present invention is to provide a method for producing a carbon-coated lithium oxide having high conductivity, and a carbon-coated lithium oxide.
　本発明の一態様は、カーボン被覆リチウム酸化物の製造方法であって、カーボンを粉砕装置で粉砕する粉砕工程と、粉砕したカーボンを前記粉砕装置の容器壁面に付着させる付着工程と、前記容器壁面に付着したカーボンを、リチウム酸化物の表面に被覆する被覆工程と、を含む。 One aspect of the present invention is a method for producing a carbon-coated lithium oxide, which comprises a crushing step of crushing carbon with a crushing device, an adhesion step of adhering the crushed carbon to the container wall surface of the crushing device, and the container wall surface. Includes a coating step of coating the surface of the lithium oxide with the carbon adhering to the.
　本発明の一態様は、カーボン被覆リチウム酸化物であって、リチウム酸化物の表面がカーボンで被覆され、前記カーボンは、粉砕装置で粉砕され、前記粉砕装置の容器壁面に付着されたカーボンである。 One aspect of the present invention is a carbon-coated lithium oxide, wherein the surface of the lithium oxide is coated with carbon, and the carbon is crushed by a crusher and adhered to the container wall surface of the crusher. ..
　本発明によれば、導電性が高い、カーボン被覆リチウム酸化物の製造方法、および、カーボン被覆リチウム酸化物を提供することができる。 According to the present invention, it is possible to provide a method for producing a carbon-coated lithium oxide having high conductivity and a carbon-coated lithium oxide.
本発明の実施形態に係るリチウム酸化物の製造方法を示すフローチャートである。It is a flowchart which shows the manufacturing method of the lithium oxide which concerns on embodiment of this invention. 遊星ボールミルの容器の外観図である。It is an external view of the container of a planetary ball mill. 付着工程における、ジャー壁面の拡大図である。It is an enlarged view of the jar wall surface in the attachment process. 付着工程後の遊星ボールミルの容器の外観図である。It is an external view of the container of the planetary ball mill after the attachment process. 被覆工程における、ジャー壁面の拡大図である。It is an enlarged view of the jar wall surface in a covering process. 被覆工程前後における、リチウム酸化物の拡大図である。It is an enlarged view of the lithium oxide before and after the coating process.
　以下、本発明の実施の形態について図面を用いて説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　〔実施形態の製造方法〕
　図１は、本発明の実施形態に係る、カーボン被覆リチウム酸化物の製造方法を示すフローチャートである。カーボン被覆リチウム酸化物は、カーボンが被覆（コーティング）されたリチウム酸化物である。本実施形態の製造方法は、粉砕工程（ステップＳ１）と、付着工程（ステップＳ２）と、被覆工程（ステップＳ３）とを含む。 [Manufacturing method of embodiment]
FIG. 1 is a flowchart showing a method for producing a carbon-coated lithium oxide according to an embodiment of the present invention. The carbon-coated lithium oxide is a lithium oxide coated with carbon. The manufacturing method of the present embodiment includes a pulverization step (step S1), an adhesion step (step S2), and a coating step (step S3).
　本実施形態では、カーボンを被覆することで、リチウム酸化物に電子伝導性を付与する。カーボンは、炭素から構成されていればよく、原料は特に限定されることはない。カーボンは、例えば、カーボンブラック、カーボンナノチューブ、フラーレン、グラフェン、グラファイト、非晶質カーボンからなる群より選択される少なくとも一種を含む。本実施形態では、カーボンブラックを用いたが、前記群のいずれかのカーボンを用いてもよく、あるいは、前記群から２種類以上を選択して混合したカーボンを用いてもよい。 In this embodiment, the lithium oxide is imparted with electron conductivity by coating it with carbon. The carbon may be composed of carbon, and the raw material is not particularly limited. Carbon includes, for example, at least one selected from the group consisting of carbon black, carbon nanotubes, fullerenes, graphene, graphite and amorphous carbon. In this embodiment, carbon black is used, but carbon black from any of the above groups may be used, or two or more types of carbon may be selected and mixed from the above group.
　リチウム酸化物には、例えばＬｉ２ＣｏＰＯ４Ｆなどを用いることができる。本実施形態では、リチウム酸化物にＬｉ２ＣｏＰＯ４Ｆを用いるが、これに限定されない。 For the lithium oxide, for example, Li2CoPO4F or the like can be used. In this embodiment, Li2CoPO4F is used as the lithium oxide, but the present invention is not limited to this.
　各工程（ステップＳ１～Ｓ３）は、不活性ガス中で行われる。本実施形態では、窒素雰囲気下で各工程を行ったが、不活性ガスであれば何でもよく、例えば、アルゴン、ヘリウムなどを使用することができる。また、空気中にても同様の効果が得られるが、各工程中に一部の炭素が酸素と化学反応を起こし、二酸化炭素になるため、カーボン被覆リチウム酸化物の収率が低下してしまう。 Each step (steps S1 to S3) is performed in an inert gas. In the present embodiment, each step is carried out in a nitrogen atmosphere, but any inert gas may be used, and for example, argon, helium or the like can be used. Further, the same effect can be obtained in air, but a part of carbon chemically reacts with oxygen during each process to become carbon dioxide, so that the yield of carbon-coated lithium oxide decreases. ..
　粉砕工程は、前述のカーボンを粉砕装置で粉砕する（ステップＳ１）。粉砕工程は、例えば、ミキサー、ホモジナイザー、超音波ホモジナイザー、高速回転せん断型撹拌機、コロイドミル、ロールミル、高圧噴射式分散機、回転ボールミル、振動ボールミル、遊星ボールミル、アトライターなどの粉砕装置を使用して、カーボンを粉末状にする。 In the crushing step, the above-mentioned carbon is crushed by a crushing device (step S1). The crushing process uses, for example, a crushing device such as a mixer, a homogenizer, an ultrasonic homogenizer, a high-speed rotary shear type stirrer, a colloidal mill, a roll mill, a high-pressure injection disperser, a rotary ball mill, a vibration ball mill, a planetary ball mill, and an attritor. And powder the carbon.
　この場合、粉砕したカーボンは、二次粒子径が１ｎｍ～１μｍであることが好ましく、１ｎｍ～０．５μｍがより好ましい。一般的に、リチウム二次電池に用いられるリチウム酸化物の粒径は、１μｍ～１０μｍであり、リチウム酸化物の粒にカーボンを密着させて被覆するには、カーボンの粒径は、大きくともリチウム酸化物の粒径の１／２０以下とすることが望ましいためである。カーボンの粒径が小さいほどカーボン間の空隙率が下がり、カーボンの密度が上がって導電性パスとして良好になることはいうまでもない。 In this case, the crushed carbon preferably has a secondary particle size of 1 nm to 1 μm, and more preferably 1 nm to 0.5 μm. Generally, the particle size of lithium oxide used in a lithium secondary battery is 1 μm to 10 μm, and in order to adhere carbon to the particles of lithium oxide for coating, the particle size of carbon is at most lithium. This is because it is desirable that the particle size of the oxide is 1/20 or less. Needless to say, the smaller the grain size of carbon, the lower the porosity between carbons, and the higher the density of carbon, which improves the conductive path.
　本実施形態では、遊星ボールミルを用いてカーボンを粉砕する。遊星ボールミルを用いた製造法は、粒子に強い遠心力を印加できるため、粒子を微粒化する手法として、好ましい。 In this embodiment, carbon is crushed using a planetary ball mill. The manufacturing method using a planetary ball mill is preferable as a method for atomizing particles because a strong centrifugal force can be applied to the particles.
　図２に、遊星ボールミルのジャー１（容器）の外観図を示す。ジャー１内部は中空で、壁面２を有する。粉砕工程では、ジャー１の中に、カーボンとジルコニアビーズを入れ、ジャー１を自転および公転させることによって、カーボンを粉砕する。ここでは、公自転比は１：－２とした。付着工程および被覆工程も、同様に、公自転比は１：－２とした。 FIG. 2 shows an external view of the jar 1 (container) of the planetary ball mill. The inside of the jar 1 is hollow and has a wall surface 2. In the crushing step, carbon and zirconia beads are placed in the jar 1 and the jar 1 is rotated and revolved to crush the carbon. Here, the rotation ratio is 1: -2. Similarly, in the adhesion step and the coating step, the rotation ratio was set to 1: -2.
　粉砕工程における遊星ボールミルの容器の公転回転数は、１００ｒｐｍ以上とすることが好ましい。１００ｒｐｍ以上とすることで、カーボンを粉砕することができ、後述する被覆工程を経た後、リチウム酸化物に電気伝導性を付与することができる。公転の回転数が、３００ｒｐｍ以上の場合はカーボンを微粒化することができるため、より好ましい。公転の回転数が１００ｒｐｍ未満の場合は、カーボンを粉砕することができず、後述する被覆工程を経た後、リチウム酸化物に電気伝導性を付与することができない。 The revolution speed of the container of the planetary ball mill in the crushing step is preferably 100 rpm or more. By setting the speed to 100 rpm or more, carbon can be pulverized, and after undergoing a coating step described later, electrical conductivity can be imparted to the lithium oxide. When the revolution speed is 300 rpm or more, carbon can be atomized, which is more preferable. When the revolution speed is less than 100 rpm, the carbon cannot be pulverized, and the lithium oxide cannot be imparted with electrical conductivity after undergoing the coating step described later.
　公転の回転数が高いほど、カーボン４とジャー壁面２とにより強い遠心力を印加することができ、回転する時間（当該工程の処理時間）を短縮することができる。また、公転の回転数が高いほど、カーボンを微粒化することができる。 The higher the revolution speed, the stronger centrifugal force can be applied to the carbon 4 and the jar wall surface 2, and the rotation time (processing time of the process) can be shortened. Further, the higher the revolution speed, the finer the carbon can be.
　また、カーボンを単独で粉砕した場合、粉砕時または粉砕後にカーボンの粉末を舞わないようにするため、カーボンに有機溶媒を含浸させてから粉砕してもよい。 Further, when carbon is crushed alone, carbon may be impregnated with an organic solvent and then crushed in order to prevent the carbon powder from flying during or after crushing.
　ここで用いる有機溶媒は、特に限定されない。有機溶媒には、例えば、３ － メチル － ３ － メトキシブチルエーテル、３ － メチル－ ３ － メトキシブタノール、ｎ－ブタノール、ｎ－ブチルアミン、ｎ－メチルピロリドン、アセトン、イソアミルアルコール、イソブタノール、イソプロパノール、エタノール、エチルカルビトール、エチレングリコール、エチレングリコールエチルエーテルアセテート、エチレングリコールブチルエーテル、オクタノール、カルボン酸、ジエチレングリコールメチルエーテル、ジプロピレングリコールイソプロピルエチルエーテル、ジプロピレングリコールイソプロピルメチルエーテル、ジプロピレングリコールエチルエーテル、ジプロピレングリコールメチルエーテル、ドデカン、トリプロピレングリコールメチルエーテル、プロパノール、プロピレングリコールエチルエーテルアセテート、プロピレンモノメチルエーテル、ヘキサデカン、ヘプタン、メタノール、酢酸ブチル、乳酸ブチル、不飽和脂肪酸、グリセリンからなる群より選択される少なくとも１種を用いることができる。 The organic solvent used here is not particularly limited. Examples of the organic solvent include 3-methyl-3-methoxybutyl ether, 3-methyl-3-methoxybutanol, n-butanol, n-butylamine, n-methylpyrrolidone, acetone, isoamyl alcohol, isobutanol, isopropanol, ethanol, and the like. Ethylcarbitol, ethylene glycol, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether, octanol, carboxylic acid, diethylene glycol methyl ether, dipropylene glycol isopropyl ethyl ether, dipropylene glycol isopropylmethyl ether, dipropylene glycol ethyl ether, dipropylene glycol methyl At least one selected from the group consisting of ether, dodecane, tripropylene glycol methyl ether, propanol, propylene glycol ethyl ether acetate, propylene monomethyl ether, hexadecane, heptane, methanol, butyl acetate, butyl lactate, unsaturated fatty acid, and glycerin. Can be used.
　カーボンを有機溶媒に含侵する場合、有機溶媒を完全に蒸発させる必要がある。そのため、被覆工程（ステップＳ３）の後に乾燥工程を行ってもよい。乾燥工程は、溶媒を含んだカーボンが被覆されたリチウム酸化物を、恒温槽、乾燥機、自然乾燥等で乾燥させることで、溶剤を除去する。溶剤の除去が可能であれば、特に乾燥温度に制限はないが、使用する溶剤の沸点、引火点及び、発火点以下の温度で加熱することで、乾燥時間を短縮することができる。 When carbon is impregnated in an organic solvent, it is necessary to completely evaporate the organic solvent. Therefore, a drying step may be performed after the coating step (step S3). In the drying step, the solvent is removed by drying the lithium oxide coated with the carbon containing the solvent in a constant temperature bath, a dryer, natural drying or the like. If the solvent can be removed, the drying temperature is not particularly limited, but the drying time can be shortened by heating at a temperature equal to or lower than the boiling point, the flash point, and the ignition point of the solvent to be used.
　付着工程は、粉砕したカーボンを粉砕装置の容器壁面に付着させる（ステップＳ２）。具体的には、付着工程は、混合する容器の壁面にカーボンを高密度に付着させる工程である。付着工程では、例えば、高圧噴射式分散機、回転ボールミル、振動ボールミル、遊星ボールミル、アトライター、混練機などを使用することができる。本実施形態では、粉砕工程で使用した遊星ボールミル（粉砕装置）を用いて、カーボンをジャー１（容器）の壁面２に付着させる。遊星ボールミルを用いた製造法は、粒子と壁面２に強い遠心力６を印加できるため、好ましい。 In the attachment step, the crushed carbon is attached to the container wall surface of the crusher (step S2). Specifically, the adhesion step is a step of adhering carbon to the wall surface of the mixing container at high density. In the bonding step, for example, a high-pressure injection type disperser, a rotary ball mill, a vibrating ball mill, a planetary ball mill, an attritor, a kneader, or the like can be used. In the present embodiment, carbon is attached to the wall surface 2 of the jar 1 (container) by using the planetary ball mill (crushing device) used in the crushing step. The manufacturing method using a planetary ball mill is preferable because a strong centrifugal force 6 can be applied to the particles and the wall surface 2.
　図３に、付着工程における、ジャー壁面２の拡大図を示す。ジルコニアビーズ３とジャー壁面２の間に、カーボン４（カーボン粒子）が存在するとき、遠心力６によって、カーボン４がジャー壁面２に付着し、ジャー壁面２にカーボン４Ａ（カーボン膜、カーボン層）が形成される。 FIG. 3 shows an enlarged view of the jar wall surface 2 in the attachment process. When carbon 4 (carbon particles) is present between the zirconia beads 3 and the jar wall surface 2, the carbon 4 adheres to the jar wall surface 2 due to the centrifugal force 6, and the carbon 4A (carbon film, carbon layer) is attached to the jar wall surface 2. Is formed.
　このとき、ジャー１の公転の回転数が、３００ｒｐｍ以上の場合、カーボン４をジャー壁面２に付着することができる。しかし、公転の回転数が３００ｒｐｍ未満の場合、カーボン４をジャー壁面２に付着することができない。そのため、付着工程における遊星ボールミルのジャー１の公転回転数は、３００ｒｐｍ以上とすることが好ましい。公転の回転数が高いほど、カーボン４とジャー壁面２とにより強い遠心力を印加することができ、回転する時間を短縮することができる。また、公転の回転数が高いほど、より密度の高いカーボンの膜４Ａを、ジャー壁面２に形成することができる。 At this time, if the revolution speed of the jar 1 is 300 rpm or more, the carbon 4 can be attached to the jar wall surface 2. However, when the revolution speed is less than 300 rpm, the carbon 4 cannot be attached to the jar wall surface 2. Therefore, the revolution speed of the jar 1 of the planetary ball mill in the attachment step is preferably 300 rpm or more. The higher the revolution speed, the stronger centrifugal force can be applied to the carbon 4 and the jar wall surface 2, and the rotation time can be shortened. Further, the higher the revolution speed, the higher the density of the carbon film 4A can be formed on the jar wall surface 2.
　なお、公転の回転数が３００ｒｐｍ未満の場合、カーボン４をジャー壁面２に付着することができないが、次の被覆工程で公転回転数が３００ｒｐｍ以上あれば、ジャー壁面への付着と、リチウム酸化物への被覆が同時に行われる。 If the revolution speed is less than 300 rpm, the carbon 4 cannot adhere to the jar wall surface 2, but if the revolution speed is 300 rpm or more in the next coating step, the carbon 4 adheres to the jar wall surface and lithium oxide. The coating is done at the same time.
　図４に、付着工程後の遊星ボールミルのジャー１の外観図を示す。図示するように、ジャー壁面にはカーボンの膜４Ａが形成されている。 FIG. 4 shows an external view of the jar 1 of the planetary ball mill after the attachment process. As shown in the figure, a carbon film 4A is formed on the wall surface of the jar.
　被覆工程は、容器壁面に付着したカーボンを、リチウム酸化物の表面に被覆する（ステップＳ３）。具体的には、被覆工程は、付着工程でジャー壁面２に作製したカーボン４Ａをリチウム酸化物に被覆させる工程である。本実施形態では、粉砕工程および付着工程で使用した遊星ボールミル（粉砕装置）にリチウム酸化物を投入し、ジャー壁面２に付着したカーボンをリチウム酸化物に被覆する。遊星ボールミルを使用する場合、例えばジルコニアビーズを用いてリチウム酸化物をカーボンに強く接触させることで、リチウム酸化物にカーボンを付着させる。 In the coating step, the carbon adhering to the wall surface of the container is coated on the surface of the lithium oxide (step S3). Specifically, the coating step is a step of coating the lithium oxide with the carbon 4A produced on the jar wall surface 2 in the bonding step. In the present embodiment, the lithium oxide is charged into the planetary ball mill (crushing device) used in the crushing step and the bonding step, and the carbon adhering to the jar wall surface 2 is coated with the lithium oxide. When a planetary ball mill is used, carbon is attached to the lithium oxide by strongly contacting the lithium oxide with the carbon using, for example, zirconia beads.
　図５に、被覆工程における、ジャー壁面２の拡大図を示す。ジルコニアビーズ３とジャー壁面２との間に、リチウム酸化物７が存在するとき、遠心力６によって、ジャー壁面２に付着したカーボン４Ａがリチウム酸化物７に被覆し、カーボン４Ａが被覆されたリチウム酸化物７が形成される。 FIG. 5 shows an enlarged view of the jar wall surface 2 in the covering process. When the lithium oxide 7 is present between the zirconia beads 3 and the jar wall surface 2, the carbon 4A adhering to the jar wall surface 2 is coated on the lithium oxide 7 by the centrifugal force 6, and the lithium oxide is coated with the carbon 4A. Oxide 7 is formed.
　図６は、被覆工程の前と後における、リチウム酸化物７の拡大図である。被覆工程で、ジャー１の公転回転数が、３００ｒｐｍ以上の場合、リチウム酸化物７に高密度のカーボン４Ａを付着させることができる。しかし、公転の回転数が３００ｒｐｍ未満の場合、カーボン４Ａをリチウム酸化物７に付着することができない。そのため、被覆工程における遊星ボールミルのジャー１の公転回転数は、３００ｒｐｍ以上とすることが好ましい。 FIG. 6 is an enlarged view of the lithium oxide 7 before and after the coating process. In the coating step, when the revolution speed of the jar 1 is 300 rpm or more, high-density carbon 4A can be attached to the lithium oxide 7. However, when the revolution speed is less than 300 rpm, the carbon 4A cannot be attached to the lithium oxide 7. Therefore, the revolution speed of the jar 1 of the planetary ball mill in the covering step is preferably 300 rpm or more.
　公転の回転数が高いほど、カーボン４Ａとリチウム酸化物７に強い遠心力を印加することができ、回転する時間を短縮することができる。また、公転の回転数が高いほど、より少ないカーボン量でリチウム酸化物７を被覆することができる。したがって、導電性が高いカーボン被覆リチウム酸化物を製造することができる。 The higher the revolution speed, the stronger centrifugal force can be applied to the carbon 4A and the lithium oxide 7, and the rotation time can be shortened. Further, as the revolution speed is higher, the lithium oxide 7 can be coated with a smaller amount of carbon. Therefore, it is possible to produce a carbon-coated lithium oxide having high conductivity.
　なお、公転の回転数が３００ｒｐｍ未満の場合、カーボン４Ａをリチウム酸化物７に付着することができないが、前の付着工程で公転回転数が３００ｒｐｍ以上あれば、ジャー壁面への付着と、リチウム酸化物への被覆が同時に行われる。 If the revolution speed is less than 300 rpm, carbon 4A cannot be attached to the lithium oxide 7, but if the revolution speed is 300 rpm or more in the previous attachment step, it adheres to the jar wall surface and lithium oxide. The covering of the object is performed at the same time.
　以上述べたように、本実施形態のカーボン被覆リチウム酸化物の製造方法は、カーボンを粉砕装置で粉砕する粉砕工程と、粉砕したカーボンを前記粉砕装置の容器壁面に付着させる付着工程と、前記容器壁面に付着したカーボンを、リチウム酸化物の表面に被覆する被覆工程と、を含む。 As described above, the method for producing the carbon-coated lithium oxide of the present embodiment includes a crushing step of crushing carbon with a crushing device, an adhesion step of adhering the crushed carbon to the container wall surface of the crushing device, and the container. It includes a coating step of coating the surface of the lithium oxide with carbon adhering to the wall surface.
　また、本実施形態のカーボン被覆リチウム酸化物は、リチウム酸化物の表面がカーボンで被覆され、前記カーボンは、粉砕装置で粉砕され、前記粉砕装置の容器壁面に付着されたカーボンである。 Further, the carbon-coated lithium oxide of the present embodiment is carbon in which the surface of the lithium oxide is coated with carbon, the carbon is crushed by a crushing device, and the carbon is adhered to the container wall surface of the crushing device.
　〔実施形態および比較例の評価〕
　本実施形態のカーボン被覆リチウム酸化物の効果を確認する目的で、本実施形態の製造方法で作製したカーボン被覆リチウム酸化物（実験例１－４）と、本実施形態とは異なる製造方法で作製したカーボン被覆リチウム酸化物（比較例）とについて実験した。 [Evaluation of Embodiments and Comparative Examples]
For the purpose of confirming the effect of the carbon-coated lithium oxide of the present embodiment, the carbon-coated lithium oxide (Experimental Example 1-4) produced by the production method of the present embodiment is produced by a production method different from that of the present embodiment. An experiment was carried out with a carbon-coated lithium oxide (comparative example).
　具体的には、実験例および比較例のカーボン被覆リチウム酸化物（正極活物質）のペレットの抵抗を測定する実験を行った。ここでは、リチウム酸化物に、ポリアニオン系正極活物質であるＬｉ２ＣｏＰＯ４Ｆを用いた。 Specifically, an experiment was conducted to measure the resistance of the pellets of carbon-coated lithium oxide (positive electrode active material) in the experimental example and the comparative example. Here, Li2CoPO4F, which is a polyanionic positive electrode active material, was used as the lithium oxide.
　（実験例１）
　実験例１では、粉砕工程は、Ｒｅｔｓｃｈ社の遊星ボールミル（型番：ＰＭ１００）に、直径２ｍｍのジルコニアボールと直径１ｍｍのジルコニアボールを１：１の割合で投入し、ケッチェンブラック（カーボン）を混合した。遊星ボールミルの公転回転数を１００ｒｐｍにして１時間回転し、ケッチェンブラックを粉砕した。なお、遊星ボールミルの公転回転数を５０ｒｐｍにして１時間回転させたケッチェンブラックをふるいにかけたところ、ケッチェンブラックは粉砕されず、ふるい上に残った。 (Experimental Example 1)
In Experimental Example 1, in the crushing step, zirconia balls having a diameter of 2 mm and zirconia balls having a diameter of 1 mm were put into a planetary ball mill (model number: PM100) manufactured by Retsch at a ratio of 1: 1 and mixed with Ketjen black (carbon). bottom. The planetary ball mill was rotated at 100 rpm for 1 hour to crush Ketjen black. When Ketjen Black, which had been rotated for 1 hour at a revolution speed of 50 rpm of the planetary ball mill, was sieved, Ketjen Black was not crushed and remained on the sieve.
　付着工程は、粉砕工程と同じ遊星ボールミルを用い、遊星ボールミルの公転回転数を１００ｒｐｍにして１時間回転させて、粉砕工程で粉砕したケッチェンブラックを容器壁面に付着した。 In the adhesion step, the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 100 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface.
　被覆工程は、付着工程と同じ遊星ボールミルにリチウム酸化物（Ｌｉ２ＣｏＰＯ４Ｆ）を投入し、当該遊星ボールミルの公転回転数を１００ｒｐｍにして１時間回転させて、カーボン被覆リチウム酸化物を作製した。 In the coating step, lithium oxide (Li2CoPO4F) was put into the same planetary ball mill as the adhesion step, and the revolution speed of the planetary ball mill was set to 100 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
　（実験例２）
　実験例２では、実験例１と同様の粉砕工程を行い、ケッチェンブラックを粉砕した。付着工程は、粉砕工程と同じ遊星ボールミルを用い、遊星ボールミルの公転回転数を１００ｒｐｍにして１時間回転させて、粉砕工程で粉砕したケッチェンブラックを容器壁面に付着した。被覆工程は、付着工程と同じ遊星ボールミルにリチウム酸化物（Ｌｉ２ＣｏＰＯ４Ｆ）を投入し、当該遊星ボールミルの公転回転数を３００ｒｐｍにして１時間回転させて、カーボン被覆リチウム酸化物を作製した。 (Experimental Example 2)
In Experimental Example 2, the same crushing step as in Experimental Example 1 was performed to crush Ketjen Black. In the adhesion step, the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 100 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface. In the coating step, lithium oxide (Li2CoPO4F) was put into the same planetary ball mill as the adhesion step, and the revolution speed of the planetary ball mill was set to 300 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
　（実験例３）
　実験例３では、実験例１と同様の粉砕工程を行い、ケッチェンブラックを粉砕した。付着工程は、粉砕工程と同じ遊星ボールミルを用い、遊星ボールミルの公転回転数を３００ｒｐｍにして１時間回転させて、粉砕工程で粉砕したケッチェンブラックを容器壁面に付着した。被覆工程は、付着工程と同じ遊星ボールミルにリチウム酸化物（Ｌｉ２ＣｏＰＯ４Ｆ）を投入し、当該遊星ボールミルの公転回転数を１００ｒｐｍにして１時間回転させて、カーボン被覆リチウム酸化物を作製した。 (Experimental Example 3)
In Experimental Example 3, the same crushing step as in Experimental Example 1 was performed to crush Ketjen Black. In the adhesion step, the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 300 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface. In the coating step, lithium oxide (Li2CoPO4F) was put into the same planetary ball mill as the adhesion step, and the revolution speed of the planetary ball mill was set to 100 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
　（実験例４）
　実験例４では、実験例１と同様の粉砕工程を行い、ケッチェンブラックを粉砕した。付着工程は、粉砕工程と同じ遊星ボールミルを用い、遊星ボールミルの公転回転数を３００ｒｐｍにして１時間回転させて、粉砕工程で粉砕したケッチェンブラックを容器壁面に付着した。被覆工程は、付着工程と同じ遊星ボールミルにリチウム酸化物（Ｌｉ２ＣｏＰＯ４Ｆ）を投入し、当該遊星ボールミルの公転回転数を３００ｒｐｍにして１時間回転させて、カーボン被覆リチウム酸化物を作製した。 (Experimental Example 4)
In Experimental Example 4, the same crushing step as in Experimental Example 1 was performed to crush Ketjen Black. In the adhesion step, the same planetary ball mill as in the crushing step was used, the revolution speed of the planetary ball mill was set to 300 rpm, and the mixture was rotated for 1 hour, and the Ketjen black crushed in the crushing step was adhered to the container wall surface. In the coating step, lithium oxide (Li2CoPO4F) was put into the same planetary ball mill as the adhesion step, and the revolution speed of the planetary ball mill was set to 300 rpm and rotated for 1 hour to prepare a carbon-coated lithium oxide.
　（比較例）
　比較例として、リチウム酸化物であるＬｉ２ＣｏＰＯ４Ｆとカーボンであるケッチェンブラックを９０：１０の割合で乳鉢に入れ、乳棒を用いて粉砕し、リチウム酸化物の周囲にカーボンが存在しているリチウム酸化物を作製した。 (Comparative example)
As a comparative example, Li2CoPO4F, which is a lithium oxide, and Ketjen Black, which is carbon, are placed in a mortar at a ratio of 90:10, crushed using a pestle, and lithium oxide in which carbon is present around the lithium oxide. Was produced.
　（評価方法）
　実験例１－４および比較例で作製したカーボン被覆リチウム酸化物の粉体を、φ２０の容器に入れ、０．５ｋＮの圧力をかけてペレットを作製し、抵抗率を測定した。 (Evaluation method)
The carbon-coated lithium oxide powder prepared in Experimental Example 1-4 and Comparative Example was placed in a φ20 container, and a pressure of 0.5 kN was applied to prepare pellets, and the resistivity was measured.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、実験例１の抵抗率は２で、実験例２－４の抵抗率は１である。比較例の抵抗率は１０である。すなわち、本実施形態の実験例１－４の抵抗率は、比較例の抵抗率より低減していることが確認できた。したがって、実験例１－４のカーボン被覆リチウム酸化物は、比較例のカーボン被覆リチウム酸化物より導電性が高く、高エネルギー密度なリチウム電池を実現できる。 As shown in Table 1, the resistivity of Experimental Example 1 is 2, and the resistivity of Experimental Example 2-4 is 1. The resistivity of the comparative example is 10. That is, it was confirmed that the resistivity of Experimental Example 1-4 of this embodiment was lower than that of Comparative Example. Therefore, the carbon-coated lithium oxide of Experimental Example 1-4 has higher conductivity than the carbon-coated lithium oxide of Comparative Example, and can realize a lithium battery having a high energy density.
　また、付着工程または被覆工程の公転回数が３００ｒｐｍの実験例２、３と、付着工程および被覆工程の公転回数が３００ｒｐｍの実験例４の抵抗率は１である。一方、付着工程および被覆工程の公転回数が１００ｒｐｍの実験例１の抵抗率は２である。これは、付着工程および被覆工程の両方の公転回転数が低いと、ジルコニアボールと容器壁面とに印加される圧力が低く、カーボンの表面に高密度な膜がコーティングされず、正極活物質であるリチウム酸化物同士の導電パスの形成が不十分になると考えられる。 Further, the resistivity of Experimental Examples 2 and 3 in which the number of revolutions of the adhesion step or the coating step is 300 rpm and the resistivity of Experimental Example 4 in which the number of revolutions of the adhesion step and the coating step is 300 rpm is 1. On the other hand, the resistivity of Experimental Example 1 in which the number of revolutions of the adhesion step and the coating step is 100 rpm is 2. This is a positive electrode active material because when the revolution speeds of both the adhesion process and the coating process are low, the pressure applied to the zirconia ball and the container wall surface is low, and the carbon surface is not coated with a high-density film. It is considered that the formation of conductive paths between lithium oxides is insufficient.
　なお、本発明は上記実施形態に限定されるものではなく、本発明の技術的思想内で、様々な変形および組み合わせが可能である。 The present invention is not limited to the above embodiment, and various modifications and combinations are possible within the technical idea of the present invention.
　Ｓ１：粉砕工程
　Ｓ２：付着工程
　Ｓ３：被覆工程
　１　：ジャー
　２　：ジャー壁面
　３　：ジルコニアビーズ
　４、４Ａ：カーボン
　７　：リチウム酸化物　 S1: Grinding process S2: Adhesion process S3: Coating process 1: Jar 2: Jar wall surface 3: Zirconia beads 4, 4A: Carbon 7: Lithium oxide

Claims (5)

  1. 　カーボンを粉砕装置で粉砕する粉砕工程と、
    　粉砕したカーボンを前記粉砕装置の容器壁面に付着させる付着工程と、
    　前記容器壁面に付着したカーボンを、リチウム酸化物の表面に被覆する被覆工程と、を含む
    　カーボン被覆リチウム酸化物の製造方法。     A crushing process that crushes carbon with a crushing device,
    A bonding step of adhering crushed carbon to the container wall surface of the crushing device, and
    A method for producing a carbon-coated lithium oxide, which comprises a coating step of coating the surface of the lithium oxide with carbon adhering to the container wall surface.
  2. 　前記粉砕装置として遊星ボールミルを用い、
    　前記粉砕工程における前記遊星ボールミルの容器の公転回転数が、１００ｒｐｍ以上である
    　請求項１記載のカーボン被覆リチウム酸化物の製造方法。     A planetary ball mill was used as the crushing device.
    The method for producing a carbon-coated lithium oxide according to claim 1, wherein the revolution speed of the container of the planetary ball mill in the crushing step is 100 rpm or more.
  3. 　前記粉砕装置として遊星ボールミルを用い、
    　前記付着工程における前記遊星ボールミルの容器の公転回転数が、３００ｒｐｍ以上である
    　請求項１または２記載のカーボン被覆リチウム酸化物の製造方法。     A planetary ball mill was used as the crushing device.
    The method for producing a carbon-coated lithium oxide according to claim 1 or 2, wherein the revolution speed of the container of the planetary ball mill in the adhesion step is 300 rpm or more.
  4. 　前記粉砕装置として遊星ボールミルを用い、
    　前記被覆工程における前記遊星ボールミルの容器の公転回転数が、３００ｒｐｍ以上である
    　請求項１から３のいずれか１項に記載のカーボン被覆リチウム酸化物の製造方法。     A planetary ball mill was used as the crushing device.
    The method for producing a carbon-coated lithium oxide according to any one of claims 1 to 3, wherein the planetary ball mill container has a revolution rotation speed of 300 rpm or more in the coating step.
  5. 　リチウム酸化物の表面がカーボンで被覆され、
    　前記カーボンは、粉砕装置で粉砕され、前記粉砕装置の容器壁面に付着されたカーボンである
    　カーボン被覆リチウム酸化物。     The surface of the lithium oxide is coated with carbon,
    The carbon is carbon coated lithium oxide which is crushed by a crushing device and adhered to the container wall surface of the crushing device.
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Citations (6)

* Cited by examiner, † Cited by third party
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008542979A (en) * 2005-05-06 2008-11-27 フォステック リチウム インコーポレイテッド Electrode material containing lithium / transition metal composite oxide
JP2010533354A (en) * 2007-07-13 2010-10-21 ダウ グローバル テクノロジーズ インコーポレイティド Carbon coated lithium manganese phosphate cathode material
JP2009302044A (en) * 2008-05-14 2009-12-24 Tokyo Institute Of Technology Method for manufacturing inorganic particles, positive electrode of secondary battery using the same, and secondary battery
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