WO2022019313A1 - Granules d'oxyde de lithium vanadium et dispositif de stockage d'énergie - Google Patents

Granules d'oxyde de lithium vanadium et dispositif de stockage d'énergie Download PDF

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WO2022019313A1
WO2022019313A1 PCT/JP2021/027228 JP2021027228W WO2022019313A1 WO 2022019313 A1 WO2022019313 A1 WO 2022019313A1 JP 2021027228 W JP2021027228 W JP 2021027228W WO 2022019313 A1 WO2022019313 A1 WO 2022019313A1
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vanadium oxide
carbon
inner layer
particles
lithium vanadium
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PCT/JP2021/027228
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English (en)
Japanese (ja)
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勝彦 直井
和子 直井
悦郎 岩間
圭祐 松村
竜也 近藤
健治 町田
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日本ケミコン株式会社
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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
    • C01B32/00—Carbon; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G31/00—Compounds of vanadium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their 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
    • H01M4/36—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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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 granulated body of lithium vanadium oxide and a power storage device using the granulated body as an active material for an electrode as a positive electrode or a negative electrode.
  • the secondary battery uses a positive electrode in which a positive electrode material containing lithium ions is fixed to the surface of the current collector, and a negative electrode in which a negative electrode material capable of inserting and removing lithium ions is fixed to the surface of the current collector. .. Further, as the hybrid capacitor, a positive electrode having an active material having an electric double layer action such as activated carbon formed on the surface of the current collector and a negative electrode having a negative electrode material containing lithium ions fixed to the surface of the current collector are used. ..
  • These energy storage devices have advantages such as high working voltage, high energy density, light weight, and long service life, and are being actively developed as the best choice.
  • Electrode materials containing lithium ions generally do not reach the required level of conductivity. Therefore, as the electrode material containing lithium ions, a composite in which a metal compound capable of occluding and releasing lithium is supported on a carbon material as a conductive auxiliary agent is often used.
  • the metal compound include lithium cobalt oxide, lithium iron phosphate, lithium titanate, lithium manganese phosphate, lithium vanadium and the like.
  • EVs electric vehicles
  • HEVs hybrid electric vehicles
  • the power storage devices used in these automobiles are required to have high input / output.
  • One means of achieving high input / output is to make a composite of a metal compound and carbon capable of occluding and releasing lithium into nanoparticles.
  • nanoparticles the distance of the metal compound to the inside of the particles is shortened. That is, the diffusion coefficient of lithium ions is improved by making nanoparticles. Therefore, the insertion and removal of lithium ions is accelerated, and a secondary battery with high input / output can be realized.
  • nanoparticles When a granulated body is formed, many of the nanoparticles are in a dense state where they come into contact with each other, or the nanoparticles are aggregated to the extent that some of the nanoparticles are connected without grain boundaries. Then, even if the nanoparticles are formed, it becomes difficult for lithium ions to diffuse to the nanoparticles existing on the center side of the granulated body. That is, even if nanoparticles are used, the effect of increasing the input / output of the power storage device is diminished by granulation, and the capacity is also reduced.
  • An object of the present invention is to provide a lithium vanadium oxide granulation body capable of increasing input / output of a power storage device and a power storage device using the granulation body in order to solve the above problems.
  • the granulated body of lithium vanadium oxide according to the present invention contains lithium vanadium oxide and carbon, and has a double structure of an inner layer and an outer layer shell that encloses the inner layer, and the inner layer has a double structure.
  • the outer layer shell is characterized in that a plurality of particles of the lithium vanadium oxide are gathered together while maintaining grain boundaries, and at least a part of the particles of the lithium vanadium oxide are connected without grain boundaries.
  • the granulated body has a capsule structure in which the inner layer is wrapped with the outer layer shell.
  • a plurality of particles of lithium vanadium oxide are present in the inner layer while retaining nanoparticles without agglomeration. Since the nanoparticles in the inner layer are not aggregated, they contribute to high input / output of the power storage device.
  • the nanoparticles in the inner layer are wrapped in an outer shell in which a plurality of particles of lithium vanadium oxide are aggregated and do not fall apart, and the moldability and shape retention of the electrode active material layer are improved.
  • the non-aggregated state in the inner layer means a state in which a plurality of particles of lithium vanadium oxide are present while maintaining grain boundaries, and the agglomerated state in the outer layer shell means that at least a part of the lithium vanadium oxide particles are present. A state in which they are connected without a grain boundary.
  • the outer layer shell may be opened at 50 nm or more and 150 nm or less, and may have a gap portion for communicating the inner layer and the outside of the granulated body.
  • the gaps opened at 50 nm or more and 150 nm or less can allow the electrolytic solution to permeate into the inner layer. That is, even if the granulated body has a capsule structure due to the outer layer shell, lithium ions can reach the nanoparticles in the inner layer, resulting in higher input / output of the power storage device and formability and shape retention of the electrode active material layer. Is more highly compatible.
  • At least a part of the outer layer particles which are the particles of the lithium vanadium oxide in the outer layer shell may be hollow inside. Since the outer layer shell is also formed of the electrode active material, it contributes to the development of capacity. Unlike the particles in the inner layer, the outer layer particles in the outer layer shell have a surface that is connected to other particles and is difficult to touch the electrolytic solution. The surface area that comes into contact with the particles is large, and the distance to the inside of the outer layer particles is short, so that lithium ions can be easily inserted and removed.
  • a part of the carbon may be interposed between the inner layer particles which are the particles of the lithium vanadium oxide in the inner layer.
  • the carbon interposed between the inner layer particles is amorphous carbon, and the other part of the carbon may be attached to the surface of the inner layer particles as graphic carbon.
  • Amorphous carbon can create electron paths between the inner layer particles, and by using graphic carbon, that is, carbon with a high degree of graphitization and high electrical conductivity, the carbon adhering to the surface of the inner layer particles is used with respect to the inner layer particles. It becomes easier to transfer electrons. Moreover, since the graphic carbon formed on the surface of the inner layer particles does not reduce the contact ratio of the inner layer particles or create an electron path between the inner layer particles, the complex of the inner layer particles and the carbon becomes huge. However, a high ion diffusion coefficient can be realized.
  • the amorphous carbon may be contained in a proportion of 3.0 or more and 8.0 wt% or less with respect to the entire granulated body. Within this range, the granulated material develops a good capacity and has good output characteristics.
  • a further part of the carbon may be contained in the outer layer shell. Particles in the outer shell can also increase electrical conductivity.
  • the carbon may be carbonized sucrose or glucose.
  • the granulated product exhibits a good volume and has good output characteristics.
  • the lithium vanadium oxide may include Li 3 VO 4 doped with a tetravalent metal species. Further, the tetravalent metal species may be Si.
  • a power storage device in which the granulated body of this lithium vanadium oxide is contained in the positive electrode or the negative electrode is also one of the embodiments of the present invention.
  • the granulated body may be contained in which a part of the outer layer shell is collapsed and a part or the whole of the inner layer is exposed.
  • the inner layer particles can be exposed more to the electrolytic solution without significantly impairing the shape retention and moldability of the electrode active material layer, the capacity of the power storage device can be improved, and further high input / output can be realized.
  • the present invention it is possible to improve the formability and shape retention of the active material layer formed on the electrodes while achieving high input / output of the power storage device.
  • FIG. 3 is a selected area diffraction diagram of the edge region of the inner layer particles of the granulated body. It is an SEM photograph which shows the cross section of the electrode active material layer. It is a graph which shows the output characteristic of Example 1 and Comparative Example 1. It is a graph which shows the amount of graffiti carbon and amorphous carbon in the granulation body of Examples 1 to 3 and Comparative Example 2. It is a graph which shows the relationship between the discharge current density and the discharge capacity of the half cell of Comparative Example 2 and Examples 1 to 3. It is a graph which shows the relationship between the discharge current density and the discharge capacity of the half cell of Examples 1 and 4 to 6.
  • the granulation body of the present invention is an aggregate of particles of lithium vanadium oxide.
  • Lithium vanadium oxide is composited with carbon.
  • the lithium vanadium oxide is typically lithium vanadate represented by the chemical formula Li 3 VO 4.
  • Preferred is Li 3 VO 4 doped with a tetravalent metal species M, represented by the chemical formula Li 3 + x V 1-x M x O 4 , which is a solid solution of Li 3 VO 4 and Li 4 MO 4.
  • the tetravalent metal species M include Si, Ti, Ge and the like.
  • the lithium vanadium oxide doped with the tetravalent metal species M has Li 3 VO 4 as a matrix structure, and V 5+ is partially replaced with M 4+ to introduce interstitial Li.
  • the coefficient x of the metal species M is preferably 0.2 or more and 0.4 or less.
  • the lithium vanadium oxide has a single crystal structure of only the ⁇ phase in the temperature range of at least ⁇ 40 to 60 ° C. including normal temperature.
  • the crystal structure of the ⁇ phase in the lithium vanadium oxide is a so-called LISION (Lithium Super Ionic CONductor) type, and has a Pnma crystal structure. That is, the crystal of lithium vanadium oxide having a ⁇ -phase crystal structure has a tetrahedral LiO 4- coordination structure and a tetrahedral VO 4- coordination structure as basic skeletons, and an octahedral LiO 6-coordination structure. Has a structure. Since the lithium vanadium oxide crystal has a ⁇ -phase crystal structure, the mass diffusivity of lithium ions is improved. That is, in the log-log graph of the diffusion coefficient, there is no range in which the diffusion coefficient drops sharply as the capacity increases.
  • LISION Lithium Super Ionic CONductor
  • this granulated body is a true sphere and has a double structure of an outer layer shell 2 and an inner layer 3.
  • the inner layer 3 is a spherical nucleus containing the center of a true sphere.
  • the outer layer shell 2 is a shell that encloses the inner layer 3. That is, this granulated body has a capsule structure in which the inner layer 3 is surrounded by the outer layer shell 2.
  • Both the outer layer shell 2 and the inner layer 3 are composed of particles of lithium vanadium oxide.
  • the radius of the granulated body is from the center of the inner layer 3 to the outer surface of the outer layer shell 2, and the diameter of the granulated body is preferably 1 ⁇ m or more and 10 ⁇ m or less. When the diameter of the granulated body is 1 ⁇ m or more, the moldability and shape retention of the electrode active material layer containing the granulated body are good.
  • the thickness of the outer layer shell 2 is preferably 100 nm or more and 200 nm or less.
  • the thickness exceeds 200 nm, it is possible to achieve both high input / output of the power storage device and formability and shape retention of the electrode active material layer, but the ratio of the outer layer shell 2 to the granulated body becomes large, and the ions of the granulated body become large.
  • the diffusion coefficient drops below the peak, limiting the increase in input / output of the power storage device.
  • the thickness of the outer layer shell 2 is 100 nm or more, it becomes robust enough to maintain the shape of at least a part of the outer layer shell 2 in the process of forming the electrode active material layer, and it becomes easy to form the electrode active material layer.
  • the thickness of the outer layer shell 2 is 200 nm or less, the shape of the other part can be maintained while the outer layer shell 2 is partially broken by applying pressure in the process of forming the electrode active material layer. Since the shape of a part of the outer layer shell 2 is maintained, the moldability and shape retention of the electrode active material layer can be maintained without being extremely deteriorated.
  • the inner layer 3 can be exposed by collapsing a part of the outer layer shell 2. Due to the exposure of the inner layer 3, the particles of the lithium vanadium oxide of the inner layer 3 can be easily in contact with the electrolytic solution, and the ion diffusion coefficient is further improved.
  • the outer layer shell 2 is composed of primary particles of lithium vanadium oxide aggregated. Further, the outer layer shell 2 contains carbon in the same amount as the inner layer 3.
  • the primary particles of lithium vanadium oxide constituting the outer layer shell 2 are referred to as outer layer particles 21.
  • Aggregation refers to a state in which part or all of the outer layer particles 21 are integrated at the crystal level and can be observed as if they are connected without grain boundaries, and the surface of the granulated body is confirmed with a scanning electron microscope at a magnification of 100,000 times. do it.
  • the gap portion 22 is a pore penetrating the outer layer shell 2 and communicates the outer side of the granulated body with the inner layer 3.
  • the gap portion 22 has a maximum opening width of 50 nm or more and 150 nm or less so that the electrolytic solution of the power storage device can pass through the outer layer shell 2.
  • the outer layer particles 21 have a hollow portion 23 inside. That is, the inside of the outer layer particles 21 is hollow. In the power storage device, the hollow portion 23 of the outer layer particles 21 is filled with the electrolytic solution, and the surface area of the outer layer particles 21 in contact with the electrolytic solution becomes large, so that the capacity developed in the outer layer shell 2 becomes large, and the outer layer particles 21 aggregate. Even if it is done, the ion diffusion coefficient can be improved.
  • the diameter of the internal space is preferably 5 nm or more and 30 nm or less. When the diameter of the internal space is within this range, the outer layer particles 21 are less likely to collapse, and the formability and retention of the electrode active material layer are improved.
  • the particle size of the outer layer particles 21 is preferably distributed in the range of 50 nm or more and 100 nm or less.
  • the gap portion 22 having an opening width of 50 nm or more and 150 nm or less has little influence on the robustness of the granulated body, but easily allows the electrolytic solution to pass through.
  • the particle size of the outer layer particles 21 exceeds 100 nm, the gap portion 22 becomes larger, and when the opening width of the gap portion 22 exceeds 150 nm, the robustness of the granulated body drops from the peak.
  • the inner layer 3 is composed of a large number of primary particles of lithium vanadium oxide.
  • the primary particles of lithium vanadium oxide constituting the inner layer 3 are referred to as inner layer particles 31.
  • the inner layer particles 31 are housed in the inner layer 3 while suppressing aggregation.
  • the state in which aggregation is suppressed means a state in which the inner layer particles 31 are separated from each other, or even if the inner layer particles 31 are in contact with each other, the crystals are not bonded and the grain boundaries are maintained. In other words, the grain boundaries of the inner layer particles 31 can be observed with a scanning electron microscope or the like, unlike the outer layer shell 2.
  • the size of the inner layer particles 31 is not limited, but it is preferably smaller than the outer layer particles 21 and distributed in a range of 10 nm or more and 50 nm or less. As shown in FIG. 3, the graphic carbon 32 adheres to the surface of the inner layer particles 31. Further, amorphous carbon 33 exists between the inner layer particles 31. That is, the inner layer 3 is composed of particles in which inner layer particles 31 and carbon are composited, and carbon connecting the particles.
  • Amorphous carbon 33 is also called amorphous carbon and is an amorphous carbon material. Amorphous carbon 33 generally burns in a temperature range of 200 ° C. or higher.
  • the graphic carbon 32 is a carbon having a high degree of graphitization, and carbon atoms are regularly arranged as compared with the amorphous carbon 33. The graphic carbon 32 generally burns in a temperature range of 600 ° C. or higher.
  • the graphic carbon 32 and the amorphous carbon 33 form an electron path between the inner layer particles 31 to improve electrical conductivity. Further, the amorphous carbon 33 is interposed between the inner layer particles 31 to maintain a state in which the aggregation of the inner layer particles 31 is suppressed.
  • the inner layer particles 31 may be electrically connected only by the graffiti carbon 32 by thickly adhering the graffiti carbon 32, but the particles in which the graffiti carbon 32 and the inner layer particles 31 are combined become enormous. , The distance between the surface of the particles and the inside of the inner layer particles 31 becomes long. On the other hand, if the inner layer particles 31 are connected by the amorphous carbon 33, the diameter of the inner layer particles 31 covered with the graphic carbon 32 does not need to be large, and a high ion diffusion coefficient can be realized.
  • all of the carbon existing between the inner layer particles 31 does not have to be amorphous carbon 33, and a part of the carbon may be other graphitized carbon or glassy carbon. Further, the surface of the inner layer particles 31 may be at least partially covered with the graphic carbon 32, but it is more preferable that the entire surface is covered.
  • the amorphous carbon 33 it is preferable to adjust the amorphous carbon 33 so that it is contained in the granulated body in the range of 3.0 wt% or more and 8.0 wt% or less with respect to the granulated body.
  • the content of the amorphous carbon 33 is 0.2 wt% or less with respect to the granulated body, the capacity is difficult to develop even if the current density is lowered.
  • the content of the amorphous carbon 33 is 16.2 wt% or more with respect to the granulated body, the proportion of the amorphous carbon 33 having a lower electric resistance than that of the graphic carbon 32 increases, and the output characteristics deteriorate.
  • the amorphous carbon 33 is contained in the granulated body in the range of 3.0 wt% or more and 8.0 wt% or less with respect to the granulated body, the amorphous carbon 33 is 16.2 wt% with respect to the granulated body. Compared with the case where the above is included, the capacity that can be output is high for the same current density, and the decrease in the capacity that can be output is suppressed even if the current density is high.
  • the magnety phase 34 is a vanadium oxide represented by the general formula V n O 2n-1 (3 ⁇ n ⁇ 8).
  • the magnety phase 34 is, for example, any simple substance selected from compounds represented by V 4 O 7 or the general formula V n O 2n-1 (3 ⁇ n ⁇ 8), or a mixed phase of two or more.
  • the magnetic phase 34 has high electrical conductivity, and electrons that have passed through the amorphous carbon 33 and the graphic carbon 32 can be smoothly introduced and derived into the inner layer particles 31.
  • V 4 O 7 has from about 10 to 100 times the electrical conductivity than the conductive carbon black.
  • the amorphous carbon 33 which is amorphous and has a relatively high electric resistance
  • the graphic carbon 32 in which carbon electrons are regularly arranged and the electric conductivity is relatively high, and the electric conductivity are high.
  • the high magnetic phase 34 they are connected so that the electrical conductivity increases as they approach the inner layer particles 31.
  • the outer layer shell 2 is also composed of a complex of outer layer particles 21 and carbon.
  • Examples of carbon in the outer layer shell 2 and the inner layer 3 include carbonized polyhydric alcohols, polymers, sugars and amino acids.
  • Examples of the polyhydric alcohol include ethylene glycol and the like
  • examples of the polymer include polyvinyl alcohol, polyalkylene oxide, polyvinylpyrrolidone and polyacrylic acid
  • examples of the saccharide include monosaccharides such as galactose, mannose or fructose, lactose, sucrose or the like.
  • Examples include small sugars such as maltose, polysaccharides such as glycogen, starch or cellulose, or derivatives thereof, and examples of amino acids include glutamate.
  • the carbon in the outer layer shell 2 and the inner layer 3 is a carbonized saccharide, and sucrose, glucose or a mixture thereof is more preferable.
  • Granulations containing carbon formed by carbonizing saccharides such as sucrose and glucose have good output characteristics. That is, the granulation body containing carbon obtained by carbonizing sucrose or glucose has a large capacity that can be output for a wide range of current densities, and can draw out a large capacity even if it is output at a high current density.
  • the granulated body of this lithium vanadium oxide may be produced, for example, as follows. That is, as shown in FIG. 4, a lithium vanadium oxide is synthesized (step S01), and the obtained particles of the lithium vanadium oxide are pulverized as necessary to form nanoparticles (step S02), and the lithium vanadium oxide is formed. A carbon source is adhered to the surface of the nanoparticles of the above, and a composite of a lithium vanadium oxide and a carbon source is granulated (step S03), and the carbon source is carbonized by heating (step S04).
  • each material source is uniformly dispersed.
  • a mixing method of each material source for example, a solid phase method can be used using a mixer.
  • a physical force may be applied to the mixture of each material source by a bead mill, a rod mill, a roller mill, a stirring mill, a planetary mill, a vibration mill, a ball mill, a homogenizer, a homomixer or the like.
  • the mixing ratio of each material source may be according to the stoichiometric ratio of lithium vanadium oxide.
  • the lithium source a lithium-containing compound such as lithium hydroxide, lithium hydroxide hydrate, lithium acetate, lithium nitrate, lithium carbonate, lithium chloride and lithium lactate can be used.
  • vanadium sources examples include metavanadate (NH 4 VO 3 , NaVO 3, KVO 3, etc.), vanadium oxide (V 2 O 5 , V 2 O 4 , V 2 O 3 , V 3 O 4 ), vanadium (III). Acetylacetonate, vanadium (IV) oxyacetylacetonate, vanadium oxytrichloride, vanadium tetrachloride, vanadium trichloride, polyvanazinate and the like can be used.
  • the metal type M source when the metal type M is Si, a silicon oxide such as SiO 2 or Li 2 SiO 3 , powder Si, amorphous Si, or the like can be used.
  • a heat treatment process is performed after the mixing process.
  • the heat treatment step is preferably divided into a preheating step and a firing step.
  • a lithium vanadium oxide having a ⁇ -phase crystal structure can be synthesized by a preheating step, and the metal species M can be solid-dissolved by a firing step to undergo a phase transition to the present lithium vanadium oxide having a ⁇ -phase crystal structure.
  • the mixture of each material source is heated at a temperature lower than the temperature at which the structural phase transitions from the ⁇ phase to the ⁇ phase.
  • heating is performed for about 5 hours in an atmosphere of 600 or more and 800 ° C. or less and in the air.
  • the mixture of the ⁇ -phase lithium vanadium oxide crystal synthesized by the preheating step and the material source of the tetravalent metal species M is heated at a temperature higher than the temperature at which the structural phase is transferred to the ⁇ phase. ..
  • heating is performed for about 8 hours in an atmosphere of 800 or more and 1000 ° C. or less and in the air.
  • a wet pulverization treatment may be performed using a mixer.
  • a mixer for example, lithium vanadium oxide is added to an organic solvent such as ethanol, and physical force is applied by a bead mill, rod mill, roller mill, stirring mill, planetary mill, vibration mill, ball mill, homogenizer, homomixer, etc. Just add it.
  • lithium vanadium oxide may be added to water and stirred well with a mixer or the like to disperse the particles.
  • a spray-drying process can be used in the coating and granulation steps of step S03.
  • nanoparticles of lithium vanadium oxide are dispersed in a solution of a carbon source, and hot air is brought into contact with the dispersion to evaporate the solvent.
  • the surface of the nanoparticles of the lithium vanadium oxide is coated with a carbon source, and a granulated body of the nanoparticles of the lithium vanadium oxide whose surface is coated with the carbon source is produced.
  • the carbon source may be any material that can become carbon by heat treatment, and examples thereof include polyhydric alcohols, polymers, sugars and amino acids.
  • polyhydric alcohol include ethylene glycol and the like
  • polymer include polyvinyl alcohol, polyalkylene oxide, polyvinylpyrrolidone and polyacrylic acid
  • saccharide include monosaccharides such as galactose, mannose or fructose, lactose, sucrose or the like.
  • examples thereof include small sugars such as maltose, polysaccharides such as glycogen, starch or cellulose, or derivatives thereof
  • amino acids include glutamate.
  • any liquid that does not adversely affect the reaction can be used without particular limitation.
  • water, methanol, ethanol, isopropyl alcohol and the like can be used, and it is particularly preferable to use water.
  • Two or more kinds of solvents may be mixed and used.
  • the method for dispersing the carbon source and the nanoparticles of the lithium vanadium oxide with respect to the solvent include ultracentrifugal treatment (treatment of applying shear stress and centrifugal force to the powder in a solution), a bead mill, a homogenizer, and the like.
  • the treatment may be performed at a pressure of about 0.1 MPa at a temperature at which the carbon source is not burnt down.
  • step S04 carbon is produced by carbonizing a carbon source coated with nanoparticles of lithium vanadium oxide.
  • graphic carbon 32 is generated on the surface of the inner layer particles 31 by carbonization of the carbon source, and amorphous carbon 33 is generated between the inner layer particles 31 by carbonization of the carbon source.
  • amorphous carbon 33 is generated between the inner layer particles 31 by carbonization of the carbon source.
  • the granulated material is heated in an oxygen-free or hypoxic atmosphere so that the carbon source does not burn.
  • the oxygen-free or low-oxygen atmosphere includes an inert atmosphere and a saturated steam atmosphere, typically in vacuum, nitrogen or argon atmosphere.
  • the temperature in the atmosphere is preferably 650 or more and 750 ° C. or less, and is preferably maintained in this temperature range for 5 hours. Within this range, a granulated body having a double structure having a good outer layer shell 2 and an inner layer 3 can be obtained, and good input / output characteristics can be obtained.
  • the lithium vanadium oxide is doped with nitrogen to increase the conductivity, which is more preferable.
  • the above-mentioned granulated body of lithium vanadium oxide is a material in which lithium ions can be reversibly inserted and removed.
  • Lithium vanadium oxide has a lower charge / discharge potential (vs Li / Li +) than lithium titanate (Li 4 Ti 5 O 12 ) and B-type titanium oxide (TIO 2 (B)), and has a charge / discharge potential (vs Li /).
  • Li + is higher than graphite. Therefore, this lithium vanadium oxide granule is suitable for use as an electrode material for a power storage device.
  • a power storage device that uses lithium vanadium oxide as the negative electrode material achieves both high energy density and high safety. Further, the theoretical capacity of the capacitor using the lithium vanadium oxide crystal as the negative electrode material is higher than that of lithium titanate, and the capacitor using the lithium vanadium oxide as the negative electrode material maintains a high capacity in terms of cycle characteristics. Maintain rate and high charge / discharge efficiency.
  • Examples of power storage devices include lithium ion secondary batteries and hybrid capacitors.
  • the positive electrode has an electrode active material layer containing a lithium metal compound
  • the negative electrode has an electrode active material layer containing a granule of the present lithium vanadium oxide.
  • the hybrid capacitor the positive electrode has, for example, activated carbon
  • the negative electrode has an electrode active material layer containing granulations of the present lithium vanadium oxide.
  • the granulated body of this lithium vanadium oxide is contained in the active material slurry by being kneaded together with the binder. After the active material slurry is molded into a predetermined shape and dried, it is pressure-bonded to a current collector and rolled to produce an electrode active material layer on the negative electrode. Alternatively, the active material slurry may be applied to the current collector by a doctor blade method or the like, dried, and then rolled.
  • the granulated body has a capsule structure in which the inner layer 3 composed of nanoparticles is surrounded by the outer layer shell 2, and the particle size is 1 ⁇ m or more. Demonstrates excellent formability and retention. That is, the molded body does not easily collapse, and the applied active material slurry does not easily drip.
  • conductive materials such as aluminum, copper, iron, nickel, titanium, steel, and carbon are preferable for both the positive electrode and the negative electrode.
  • aluminum or copper having high thermal conductivity and electron conductivity is preferable.
  • shape of the current collector any shape such as a film shape, a foil shape, a plate shape, a net shape, an expanded metal shape, and a cylindrical shape can be adopted.
  • binder known binders such as polytetrafluoroethylene, polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer, polyvinyl fluoride, carboxymethyl cellulose, and spirene butadiene rubber (SBR) are used.
  • the content of the binder is preferably 1 or more and 30% by mass or less with respect to the total amount of the electrode material.
  • a press pressure of 10 to 500 MPa is applied to obtain a high-density electrode.
  • a part of the outer layer shell 2 of the granulation body is broken while maintaining the shape of the other part of the outer layer shell 2 of the granulation body by the pressing pressure. Since a part of the shape of the outer layer shell 2 remains, the inner layer particles 31 can be exposed to the electrolytic solution while maintaining the shape retention of the electrode, and the ion diffusion coefficient becomes good.
  • Examples of active materials used for the positive electrode of a secondary battery include, first, layered rock salt type LiMO 2 , layered Li 2 MnO 3- LiMO 2 solid solution, and spinel type LiM 2 O 4 (M in the formula is Mn, Fe). , Co, Ni or a combination thereof). Specific examples of these include LiCoO 2 , LiNiO 2 , LiNi 4/5 Co 1/5 O 2 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiNi 1/2 Mn 1/2 O.
  • composite oxides such as 3.
  • Carbon may be added to the active material layer of the positive electrode as a conductive auxiliary agent.
  • the carbon can be used without particular limitation as long as it has conductivity.
  • carbon black such as Ketjen black, acetylene black, channel black, fullerene, carbon nanotube, carbon nanofiber, amorphous carbon, carbon fiber, etc.
  • Examples thereof include natural graphite, artificial graphite, graphitized Ketjen black, mesoporous carbon, and vapor phase carbon fiber.
  • Activated carbon used for the active material layer of the positive electrode of the hybrid capacitor is made from natural plant tissues such as palm shavings, synthetic resins such as phenol, and fossil fuels such as coal, coke, and pitch.
  • this active material layer includes carbon black such as ketjen black, acetylene black, and channel black, carbon nanohorns, amorphous carbon, natural graphite, artificial graphite, graphitized ketchen black, mesoporous carbon, and carbon nanotubes. , Carbon nanofibers and the like may be used.
  • the specific surface area of these carbon materials may be improved by activation treatment such as steam activation, alkali activation, zinc chloride activation, electric field activation, and opening treatment.
  • the electrolyte arranged between the positive electrode and the negative electrode in the power storage device may be an electrolytic solution held in the separator, a solid electrolyte, or a gel-like electrolyte, and may be a conventional power storage device.
  • the electrolyte used in the above can be used without particular limitation.
  • lithium such as LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 is used in a solvent such as ethylene carbonate, propylene carbonate, butylene carbonate, and dimethyl carbonate.
  • the electrolytic solution in which the salt is dissolved is used in a state of being held by a separator such as a polyolefin fiber non-woven fabric or a glass fiber non-woven fabric.
  • inorganic solid electrolytes such as Li 5 La 3 Nb 2 O 12 , Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 , Li 7 La 3 Zr 2 O 12 , Li 7 P 3 S 11, etc.
  • An organic solid electrolyte composed of a composite of a lithium salt and a polymer compound such as polyethylene oxide, polymethacrylate, and polyacrylate, and a gel-like electrolyte in which an electrolytic solution is absorbed by polyvinylidene fluoride, polyacrylonitrile, or the like are also used.
  • an electrolytic solution in which a lithium salt is dissolved in propylene carbonate or the like or an electrolytic solution in which a quaternary ammonium salt is dissolved in propylene carbonate or the like is used for the hybrid capacitor.
  • the power storage device may be so-called separatorless as long as the solid electrolyte has a thickness sufficient to prevent contact between the positive and negative electrodes and has a hardness capable of maintaining its shape by itself.
  • a carbon coat layer containing a conductive agent such as graphite may be provided between the current collector and the active material layer.
  • a carbon coat layer can be formed by applying a slurry containing a conductive agent such as graphite, a binder, or the like to the surface of the current collector and drying the slurry.
  • the particle size of this granulated product can be increased to, for example, 1 ⁇ m or more, and the moldability and shape retention of the active material slurry containing the granulated product can be improved.
  • the inner layer 3 contains a large amount of nanoparticles, the capacity of the power storage device is improved and the input / output is high.
  • the inner layer particles 31 are gathered together while maintaining grain boundaries and are not aggregated. Therefore, each particle of the inner layer particles 31 can come into contact with the electrolytic solution on the entire surface or many surfaces, the capacity of the power storage device is further improved, and the input / output is further increased.
  • at least a part of the outer layer particles 21 is connected without grain boundaries to create a robust outer layer shell 2.
  • the robust outer layer shell 2 can maintain at least a part of the shape when forming the electrode active material layer, and maintains the moldability and shape retention of the electrode active material layer without breaking the nanoparticles of the inner layer 3 into pieces. can.
  • the outer layer shell 2 has a gap portion 22 that allows the inner layer 3 and the outside of the granulated body to communicate with each other even if the outer layer particles 21 are connected without grain boundaries and become dense, electrolysis is performed from the gap portion 22 to the inner layer 3.
  • the liquid can be supplied more efficiently.
  • the outer layer shell 2 is also composed of composite particles of lithium vanadium oxide and carbon, it contributes as an electrode active material.
  • the outer layer particles 21 are hollow inside and the electrolytic solution can penetrate into the inside, the surface area of the outer layer particles 21 in contact with the electrolytic solution becomes large, and the distance to the inside of the outer layer particles 21 becomes short.
  • the capacity of the outer layer shell 2 portion can also be greatly expressed, and the movement of lithium ions in the outer layer shell 2 portion also speeds up.
  • Carbon is interposed between the inner layer particles 31. This carbon prevents the agglomeration of the inner layer particles 31 and supports the high capacity and high input / output of the power storage device. Further, this carbon serves as an electron path between the inner layer particles 31 and improves the electrical conductivity of the electrode active material layer.
  • the carbon interposed between the inner layer particles 31 was amorphous carbon 33. If the inner layer particles 31 are connected by the amorphous carbon 33, the diameter of the inner layer particles 31 covered with the graphic carbon 32 does not need to be large, and a high ion diffusion coefficient can be realized. On the other hand, since the graphic carbon 32 is attached to the surface of the inner layer particles 31, it becomes easier to transfer electrons to the inner layer particles 31.
  • the amorphous carbon 33 is adjusted so as to be contained in the granulated body in a range of 3.8 wt% or more and 7.3 wt% or less with respect to the granulated body, and has a high output capacity with respect to the current density and a current density. Even if it becomes high, the decrease in the output capacity is suppressed.
  • the electrons that have passed through the amorphous carbon 33 and the graphic carbon 32 can be introduced and derived more smoothly into the inner layer particles 31.
  • Example 1 a granulated body of lithium vanadium oxide represented by the chemical formula Li 3.2 V 0.8 Si 0.2 O 4 having a Si coefficient x of 0.2 was prepared as Example 1. ..
  • Powder lithium carbonate as a lithium source (Li 2 CO 3) (trade name: 3N5, Kanto Chemical Co., Inc., 24121-08) using a powder of vanadium pentoxide as a vanadium source (V 2 O 5) (trade name: Oxidation Vanadium (V), Kanto Chemical Co., Ltd., 44017-00) was used, and silicon dioxide (SiO 2 ) powder (trade name: silicon dioxide, 99.9%, Wako Pure Chemical Industries, Ltd., 192) was used as the metal type M source. -09071) was used.
  • the lithium source, vanadium source and metal species M source were mixed according to stoichiometric ratios and the mixture was calcined.
  • the dried collection was added to water together with sucrose and the solution was stirred. To the water, 33 wt% sucrose was added to the collection. Then, coating and granulation were performed using a spray dryer (BUCHI, mini spray dryer B-290 (spray dryer)). The inlet temperature was set to 160 ° C., the aspirator operating speed was set to 100% of the maximum value, the pump output was set to 25% of the maximum value, and the solution prepared using the compressed gas of nitrogen was sprayed. After coating and granulation by the spray-drying method, the obtained granulated product was exposed to a nitrogen environment at 700 ° C. for 5 hours to carbonize sucrose.
  • BUCHI mini spray dryer B-290
  • FIG. 5 (a) and 5 (b) are photographs showing a surface SEM image
  • FIG. 5 (a) is a photograph magnified at a magnification of 2,000 times
  • FIG. 5 (b) is a photograph at a magnification of 20,000 times.
  • FIG. 5 it can be confirmed that a true spherical granule having a particle size distributed in the range of 0.51 ⁇ m or more and 15 ⁇ m or less is obtained.
  • FIG. 6 is a photograph showing a cross-sectional SEM image
  • (a) is a photograph showing the entire granulated body at a magnification of 70,000
  • (b) is an outer layer shell 2 and an inner layer 3. It is a photograph with a magnification of 100,000 times that shows the vicinity of the boundary of.
  • the granulated body has an outer layer shell 2 in which at least a part of particles are connected without grain boundaries when observed in a cross-sectional SEM image, and an inner layer 3 in which the grain boundaries of the particles are visible.
  • the outer layer shell 2 had a thickness of 100 nm or more and 300 nm or less when visually measured, and the inner layer particles 31 had a particle size of 30 nm or more and 50 nm or less when visually measured.
  • FIG. 7A is a color mapping image showing the distribution of carbon atom C
  • FIG. 7B is a color mapping image showing the distribution of oxygen atom O
  • FIG. 7C is a color mapping image. It is a color mapping image which shows the distribution of a silicon atom Si
  • (d) of FIG. 7 is a color mapping image which shows the distribution of vanadium atom V.
  • carbon atoms, oxygen atoms, silicon atoms and vanadium atoms are uniformly distributed over the entire area of the outer layer shell 2 and the inner layer 3 of the granulated body without distinction. Can be confirmed. That is, it can be confirmed that the outer layer shell 2 and the inner layer 3 are composed of carbon-composite lithium vanadium oxide particles.
  • FIG. 8A is a dark-field photograph having a magnification of 40,000 times
  • FIG. 8B is a bright-field photograph having a magnification of 40,000 times.
  • a dark-field photograph shows a dark gap 22 and a light field 22 can be seen around a heavy element that is dark in the bright-field.
  • the outer layer shell 2 of the granulated body was observed with a scanning transmission electron microscope (STEM) to obtain a STEM image at a magnification of 40,000 times shown in FIG. As shown in FIG. 9, it was confirmed that the outer layer particles 21 are hollow inside and the inner space has a width of 20 nm.
  • STEM scanning transmission electron microscope
  • FIG. 10 is a TEM image of the inner layer particles 31 of the granulated body at a magnification of 500,000 times.
  • FIG. 11 is a TEM image of the inner layer 3 of the granulated body having a magnification of 400,000 times, and the edging of the inner layer particles 31 is added.
  • FIG. 10 it can be confirmed that carbon crystals are attached to the surface of the inner layer particles 31. That is, it can be confirmed that the graphic carbon 32 is attached to the surface of the inner layer particles 31.
  • FIG. 10 is a TEM image of the inner layer particles 31 of the granulated body at a magnification of 500,000 times.
  • FIG. 11 is a TEM image of the inner layer 3 of the granulated body having a magnification of 400,000 times, and the edging of the inner layer particles 31 is added.
  • FIG. 10 it can be confirmed that carbon crystals are attached to the surface of the inner layer particles 31. That is, it can be confirmed that the graphic carbon 32 is attached to the
  • the inner layer particles 31 were observed with a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • a TEM image with a magnification of 200,000 times obtained as a result is shown in FIG.
  • the edge 31a of the inner layer particles 31 appears dark.
  • the darkened part is a crystal region composed of vanadium atoms and oxygen atoms by removing lithium atoms and silicon atoms from the lithium vanadium oxide.
  • FIG. 13 shows a selected area ED diagram. Obtains the actual measurement values based on the selected area ED view, results obtained by converting the measured value from the origin of the incident angle 2 ⁇ based on the distance to the diffraction point, to contain many V 4 O 7 in this crystal region I understand. That is, the magnetic phase 34 was confirmed on the surface of the inner layer particles 31.
  • the incident angle 2 ⁇ based on the distance from the origin to each diffraction point is 21.14 ° for the 103rd surface on the innermost circumference, and 26.76 ° for the 1-2-3 surface on the central side.
  • the granulated body of Example 1 contains lithium vanadium oxide and carbon, has a double structure of an outer layer shell 2 and an inner layer 3, and the inner layer 3 is composed of a plurality of particles of lithium vanadium oxide.
  • the outer layer shell 2 is formed by gathering together while maintaining the boundary, the outer layer shell 2 is formed by connecting at least a part of the particles of the lithium vanadium oxide without a grain boundary, and the outer layer shell 2 is opened at 50 nm or more and 150 nm or less and is formed with the inner layer 3. It has a gap 22 that communicates with the outside of the particles, at least a part of the outer layer particles 21 is hollow inside, the amorphous carbon 33 is interposed between the inner layer particles 31, and the graphic carbon 32 is the inner layer particles. It was confirmed that the particles were attached to the surface of 31 and that a part of the surface of the inner layer particles 31 was altered to the magnety phase 34.
  • the granulation body of Comparative Example 1 was produced in correspondence with the granulation body of Example 1.
  • a lithium vanadium oxide having a Si coefficient x of 0.2 and represented by the chemical formula Li 3.2 V 0.8 Si 0.2 O 4 was used as in Example 1.
  • it differs in that it is formed by granulating particles of a complex with multiwall carbon nanotubes (MWCNT).
  • MWCNT multiwall carbon nanotubes
  • the granulated body of Comparative Example 1 was prepared as follows. That is, the material source and the mixing ratio were the same as in Example 1, and mixing and firing were performed under the same method and conditions as in Example 1. After calcination, multiwall carbon nanotubes (MWCNT) were added to the collection vacuum dried at 80 ° C. overnight at a ratio of 20 wt% with respect to the collection. Then, the granulated product of Comparative Example 1 was obtained by mixing with a dry ball mill (Fritsch, Premium line P-7 (PL-7)) at a rotation speed of 300 rpm for 12 hours.
  • a dry ball mill Fritsch, Premium line P-7 (PL-7)
  • the granulation body of Comparative Example 1 was subjected to the addition of sucrose, coating and granulation by the spray dry method, and carbonization of sucrose by heating, whereas the granulation body of Example 1 was added with MWCNT and dried. It differs from the method for producing a granulated product of Example 1 in that there is no coating and granulation by a ball mill and no final heat treatment.
  • the granulated body of Comparative Example 1 has a structure in which MWCNT is attached to the surface of a lithium vanadium oxide represented by Li 3.2 V 0.8 Si 0.2 O 4 having a particle size of 50 or more and 500 nm or less. .. There is no magnety phase 34 on the surface.
  • the lithium vanadium oxide particles of Comparative Example 1 aggregate at various places to form many secondary particles, and MWCNTs intervene between the secondary particles.
  • most of the inner layer particles 31 which are primary particles do not aggregate, and the amorphous carbon 33 is interposed between the inner layer particles 31 which are primary particles.
  • the surface of the lithium vanadium oxide particles of Comparative Example 1 is not covered with the graphic carbon 32, and most of the surfaces of the lithium vanadium oxide particles of Comparative Example 1 are exposed. Further, the granulated body of Comparative Example 1 does not have an outer layer shell 2, and is formed only by a structure in which MWCNT is interposed between secondary particles.
  • thermogravimetric analysis (TG) of the granulated bodies of Example 1 and Comparative Example 1 was performed. That is, the granulated product was allowed to stand in an atmosphere where the temperature changed up to 1000 ° C., and the weight was measured. As a result, the granulated body of Example 1 contained 10.2 wt% of carbon with respect to the total amount of the granulated body. The granulated body of Comparative Example 1 contained 20 wt% of carbon with respect to the total amount of the granulated body.
  • Half cells were prepared using the granulated bodies of Example 1 and Comparative Example 1.
  • the half cell was a 2032 type coin cell. Specifically, polyvinylidene fluoride (PVDF) is selected as the binder, and the granulated body and the binder are stirred together to form a slurry, which is then applied to a copper foil current collector to form an electrode on the current collector. After forming the active material layer, a rolling process was performed. In the rolling process, a press pressure of 30 MPa was applied. This electrode is referred to as the working electrode W. E. And said.
  • PVDF polyvinylidene fluoride
  • the counter electrode was made of lithium metal and attached to the lower lid of the 2032 type coin cell. Opposite pole C. On E, a glass fiber separator, a gasket, and a working electrode W. E, spacer, spring, and top lid were placed in this order and crimped to prepare a cell.
  • FIG. 14 is an SEM photograph showing a cross section of the electrode active material layer of Example 1. As shown in FIG. 14, it can be confirmed that a part of the outer layer shell 2 of some of the granulated bodies collapses due to the rolling process and the inner layer 3 is exposed. Therefore, the inner layer 3 of the granulated body in which a part of the outer layer shell 2 is collapsed is filled with the electrolytic solution without passing through the gap portion 22 of the outer layer shell 2.
  • FIG. 15 is a graph showing the output characteristics of Example 1 and Comparative Example 1 obtained as a result of the measurement.
  • the half cell of Example 1 has a larger capacity than the half cell of Comparative Example 1 in the entire range of the discharge current density from 0.05 to 15 Ag -1.
  • the discharge capacity of the half cell of Comparative Example 1 is 134 mAhg -1, while that of the half cell of Example 1 is 154 mAhg -1 , and the capacity of Example 1 is higher than that of Comparative Example 1.
  • the ratio of the discharge capacity in the case of the discharge current density of 15 Ag -1 to the discharge capacity in the case where the discharge current density is as close to zero as possible is 50% in the half cell of Comparative Example 1 and 68 in the half cell of Example 1. %
  • the capacity of Example 1 is improved by 18% as compared with Comparative Example 1.
  • the half cell of Example 1 has a carbon amount reduced by 49% as compared with the half cell of Comparative Example 1, and has higher input / output than that of Comparative Example 1. That is, it can be confirmed that the granulated body of Example 1 has a higher capacity and higher input / output than Comparative Example 1 even though the inner layer 3 is wrapped in the outer layer shell 2. rice field.
  • Example 2 the granulated bodies of Examples 2 and 3 and the granulated bodies of Comparative Example 2 were prepared.
  • the granulated products of Examples 2 and 3 and the granulated products of Comparative Example 2 differ in the amount of sucrose added during the spray-drying treatment as compared with Example 1.
  • Example 1 33 wt% sucrose was added to the lithium vanadium oxide, whereas in Example 2, 20 wt% sucrose was added to the lithium vanadium oxide, and in Example 3, lithium vanadium was added.
  • 50 wt% sucrose was added to the oxide, and in Comparative Example 2, 11 wt% sucrose was added to the lithium vanadium oxide.
  • the production method and conditions other than the amount of sucrose added are common to Examples 1 to 3 and Comparative Example 2.
  • FIG. 16 is a graph showing the amounts of graphic carbon 32 and amorphous carbon 33 in the granulated bodies of Examples 1 to 3 and Comparative Example 2.
  • the amounts of graffiti carbon 32 and amorphous carbon 33 are based on thermogravimetric analysis (TG). That is, the weight of the amorphous carbon 33 is defined as the weight of the granulated bodies of Examples 1 to 3 and Comparative Example 2 reduced in the temperature range of 200 ° C. or higher and 400 ° C. or lower, and the atmospheric temperature is 600 ° C. or higher. The weight reduced in the temperature range of 800 ° C. or lower was defined as the weight of the graphic carbon 32. The amount of reduction was based on the result of thermogravimetric measurement of the granulated product produced by the same production method and the same conditions as in Example 1 except that carbon was not added.
  • TG thermogravimetric analysis
  • the amount of adhering graphic carbon 32 was almost constant regardless of the amount of sucrose added.
  • the granulated body of Comparative Example 2 contained 0.2 wt% of amorphous carbon 33.
  • the granulated body of Comparative Example 2 contained 2.2 wt% in total with the graphic carbon 32.
  • the granulated body of Example 2 contained 3.8 wt% of amorphous carbon 33.
  • the granulated body of Example 2 contained 7.0 wt% in total with the graphic carbon 32.
  • the granulated body of Example 1 contained 7.3 wt% of amorphous carbon 33.
  • the granulated body of Example 1 contained 10.2 wt% in total with the graphic carbon 32.
  • the granulated body of Example 3 contained 16.2 wt% of amorphous carbon 33.
  • the granulated body of Example 3 contained 18.3 wt% in total with the graphic carbon 32.
  • Half cells were prepared using the granulated bodies of Comparative Example 2 and Examples 1 to 3.
  • the half cell was produced by the same manufacturing method and under the same conditions as in Example 1 and Comparative Example 1.
  • the relationship between the discharge current density and the discharge capacity was measured for the half cells of Comparative Example 2 and Examples 1 to 3.
  • the measurement results are shown in FIG.
  • the half cell of Comparative Example 2 in which the amorphous carbon 33 was 0.2 wt% with respect to the entire granulated body did not develop the capacity in the entire range of the discharge current density.
  • the half cells of Examples 1 to 3 in which the amorphous carbon 33 was 3.8 wt% or more with respect to the entire granulated body the capacity was developed in the entire range of the discharge current density.
  • the amorphous carbon 33 is interposed between the inner layer particles 31 to suppress the aggregation of the inner layer particles 31, and if the electron path between the inner layer particles 31 is constructed, the inner layer 3 is wrapped by the outer layer shell 2.
  • the input / output characteristics of the power storage device using the granulated material were good.
  • the amorphous carbon 33 having a higher electric resistance than the graphic carbon 32 was 16.2 wt% with respect to the entire granulated body, so that the capacity is proportionally drawn out when the discharge current density becomes high. Has decreased.
  • the half cells of Examples 1 and 2 in which the amorphous carbon 33 is 3.8 wt% or more and 7.3 wt% or less with respect to the entire granulated body have a capacity to be drawn up to a discharge current density of about 10 Ag -1. The amount of decrease was suppressed.
  • the amount of decrease in the drawn capacity was particularly suppressed until the discharge current density was about 10 Ag -1.
  • the amorphous carbon 33 is 3.8 wt% or more and 7.3 wt% or less with respect to the entire granulated body, the balance between the suppression of aggregation of the inner layer particles 31 and the electrical resistance between the inner layer particles 31 becomes good. It was confirmed that the input / output characteristics of the power storage device using the granulated material were further improved.
  • Example 4 sucrose during the spray-drying treatment was added in Example 1, whereas glucose was added in the same weight as in Example 1.
  • Polyvinyl alcohol (PVA) was added to the granulated product of Example 5 by the same weight as that of Example 1.
  • Histidine was added to the granulated product of Example 6 by the same weight as that of Example 1.
  • the production method and conditions other than the type of carbon source are common to Examples 1 and 4 to 6.
  • Example 4 a half cell was prepared using the granulated bodies of Examples 4 to 6.
  • the half cell was produced by the same manufacturing method and under the same conditions as in Example 1.
  • the relationship between the discharge current density and the discharge capacity was measured.
  • the measurement results are shown in FIG. 18 together with the results of Example 1. As shown in FIG. 18, it can be confirmed that the capacity develops from a low current density to a high current density regardless of the type of carbon source, and in particular, Examples 1 and Implementation using the saccharides sucrose and glucose as carbon sources.
  • the half cell of Example 4 develops a large capacity in the entire range of the discharge current density as compared with Examples 5 and 6, and the half cell of Example 1 using sucrose as a carbon source has a large capacity in the entire range of the discharge current density. It was confirmed that the capacity was maintained.

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Abstract

L'invention concerne des granules d'oxyde de lithium vanadium permettant d'obtenir une entrée/sortie accrue dans un dispositif de stockage d'énergie, et un dispositif de stockage d'énergie dans lequel les granules sont utilisés. Les granules comprennent de l'oxyde de lithium vanadium et du carbone, et ont une structure double comprenant une couche interne 3 et une enveloppe de couche externe 2 qui enveloppe la couche interne 3. La couche interne 3 est formée par une pluralité de particules d'oxyde de lithium vanadium qui sont réunies tout en maintenant des limites de grain, et l'enveloppe de couche externe 2 est formée par connexion d'au moins certaines des particules d'oxyde de lithium vanadium sans limites de grain.
PCT/JP2021/027228 2020-07-21 2021-07-20 Granules d'oxyde de lithium vanadium et dispositif de stockage d'énergie WO2022019313A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005216855A (ja) * 2004-01-26 2005-08-11 Samsung Sdi Co Ltd リチウム二次電池用負極活物質とその製造方法及びそれを含むリチウム二次電池
CN108878788A (zh) * 2017-05-09 2018-11-23 浙江伏打科技有限公司 一种锆钒酸锂-碳锂离子电池负极材料及其制备方法
WO2019093513A1 (fr) * 2017-11-12 2019-05-16 日本ケミコン株式会社 Corps cristallin d'oxyde de vanadium et de lithium, matériau d'électrode et dispositif de stockage d'énergie

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005216855A (ja) * 2004-01-26 2005-08-11 Samsung Sdi Co Ltd リチウム二次電池用負極活物質とその製造方法及びそれを含むリチウム二次電池
CN108878788A (zh) * 2017-05-09 2018-11-23 浙江伏打科技有限公司 一种锆钒酸锂-碳锂离子电池负极材料及其制备方法
WO2019093513A1 (fr) * 2017-11-12 2019-05-16 日本ケミコン株式会社 Corps cristallin d'oxyde de vanadium et de lithium, matériau d'électrode et dispositif de stockage d'énergie

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