WO2024202644A1 - 被覆活物質粒子、活物質層、及びリチウムイオン二次電池 - Google Patents

被覆活物質粒子、活物質層、及びリチウムイオン二次電池 Download PDF

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WO2024202644A1
WO2024202644A1 PCT/JP2024/005190 JP2024005190W WO2024202644A1 WO 2024202644 A1 WO2024202644 A1 WO 2024202644A1 JP 2024005190 W JP2024005190 W JP 2024005190W WO 2024202644 A1 WO2024202644 A1 WO 2024202644A1
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Prior art keywords
active material
shell
material particles
coated
film
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English (en)
French (fr)
Japanese (ja)
Inventor
充康 今▲崎▼
純一 今泉
昌史 時實
剛 菊池
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Kaneka Corp
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Kaneka Corp
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Priority to JP2025509890A priority Critical patent/JPWO2024202644A1/ja
Priority to CN202480017817.1A priority patent/CN120898295A/zh
Publication of WO2024202644A1 publication Critical patent/WO2024202644A1/ja
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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 coated active material particles, an active material layer, and a lithium ion secondary battery.
  • Lithium nickel manganese oxide (hereinafter also referred to as LNMO) has been known as a positive electrode active material for lithium ion secondary batteries (for example, Patent Document 1).
  • the crystal structure of the active material changes when Li ions are inserted or removed, and distortion can occur within the crystal structure, causing instability.
  • the present invention aims to provide coated active material particles, an active material layer, and a lithium-ion secondary battery that can suppress the generation of gas due to decomposition of the electrolytic medium compared to conventional techniques.
  • One aspect of the present invention for solving the above-mentioned problems is a coated active material particle in which the active material particle is coated with a coating, and the coating contains a phosphate ion-containing lithium compound that contains lithium ions, metal species, and phosphate ions.
  • metal species refers to chemical species of metals, and is a concept that includes ions, atoms, atomic groups, elements, and compounds.
  • metal as used herein also includes silicon.
  • the phosphate ion-containing lithium compound contains manganese element.
  • the phosphate ion-containing lithium compound contains elemental silicon.
  • the two surfaces of the coating differ in at least one of the concentration of the phosphate ions, the concentration of the metal species, and the composition.
  • compositions refers not only to cases where the composition ratios of the constituent elements are different, but also to cases where the types of the constituent elements are different. The same applies below.
  • a preferred aspect includes a core-shell particle having a core-shell structure in which the active material particles form a core and a continuous shell film forms the shell, the shell film forms the outer surface of the core-shell particle, the coating has the shell film and a buffer portion in this order from the active material particle side, the buffer portion is formed and distributed on the outer surface of the shell film, and the coating differs on both sides of the shell film in at least one of the concentration of the phosphate ions, the concentration of the metal species, and the composition.
  • the coating has at least one of the phosphate ion concentration, the metal species concentration, and the composition different on both sides of the buffer portion.
  • the average occupancy rate of the buffer portion relative to the outer surface of the shell film per active material particle is 0.1% or more and 30% or less.
  • the phosphate ion-containing lithium compound has an olivine type crystal structure.
  • One aspect of the present invention is an active material layer including the coated active material particles described above, the coating having a shell film in contact with the active material particles, the shell film including the phosphate ion-containing lithium compound, the phosphate ion-containing lithium compound including one or more metals selected from the group consisting of Fe, Mn, Si, and Al, the cross-sectional shape of which is a sea-island structure, the active material layer having island portions and a sea-like portion, the island portions including a permeable pore network, and the sea-like portion including the active material particles, a binder, and a conductive network.
  • the shell film contains a phosphate ion-containing lithium compound containing one or more metals selected from the group consisting of Fe, Mn, Si, and Al. Therefore, when the active material is used as an electrode for a lithium ion secondary battery that uses an electrolyte solution as an electrolytic medium, gas generation due to decomposition of the electrolyte solution caused by direct exposure of the active material particles to the electrolyte solution can be suppressed. According to this aspect, since the active material has a conductive network and a permeable pore network, when the active material is used as an electrode for a lithium ion secondary battery, the exchange of charges and lithium ions between the electrolyte and the active material particles is facilitated, making it easier for the electrode reaction to occur.
  • the conductive network is at least partially in contact with the active material particles or the shell film
  • the permeable pore network has pores and is at least partially in contact with the active material particles or the shell film
  • the permeable pore network has a lithium ion conductor provided from the contact portion with the active material particles or the shell film toward the pores.
  • the active material particles are negative electrode active material particles for a lithium ion secondary battery and contain lithium titanate.
  • One aspect of the present invention is an active material layer containing active material particles for a lithium ion secondary battery, the active material layer having a cross-sectional shape of a sea-island structure, with an island portion and a sea-like portion, the island portion containing a permeable pore network, and the sea-like portion containing the active material particles, a binder, and a conductive network.
  • the buffer portion has a non-liquid lithium ion conductor having a solid electrolyte interface (SEI) structure, and the lithium ion conductor is disposed in the pore shell contact portion.
  • SEI solid electrolyte interface
  • the shell film is a lithium compound containing phosphate ions and containing one or more metals selected from the group consisting of Fe, Mn, Si, and Al.
  • One aspect of the present invention is a lithium ion secondary battery in which an electrode laminate having a positive electrode and a negative electrode facing each other with an electrolyte sandwiched therebetween is enclosed within an exterior body, and the positive electrode or the negative electrode contains the coated active material particles described above.
  • One aspect of the present invention is a coated active material particle in which active material particles are coated with a coating, the coating containing a metal component (including elemental silicon as the metal) and a phosphate ion-containing lithium compound containing phosphate ions, and the concentration of the phosphate ions differs on both sides of the coating.
  • One aspect of the present invention is a coated active material particle in which active material particles are coated with a coating, the coating containing a metal component (including elemental silicon as the metal) and a phosphate ion-containing lithium compound containing phosphate ions, and the components and/or composition of the metal are different on both sides of the coating.
  • a metal component including elemental silicon as the metal
  • a phosphate ion-containing lithium compound containing phosphate ions a phosphate ion-containing lithium compound containing phosphate ions
  • the coated active material particles, active material layer, and lithium ion secondary battery of the present invention can suppress gas generation due to decomposition of the electrolytic medium compared to conventional methods.
  • FIG. 1A is a schematic diagram illustrating a lithium ion secondary battery according to a first embodiment of the present invention
  • FIG. 1B is a cross-sectional view taken along line A-A of FIG. 1A
  • FIG. 1C is a cross-sectional view taken along line B-B of FIG. 1A
  • 2A and 2B are explanatory views of the electrode parts of the positive electrode part and the negative electrode part in FIG. 1, where FIG. 2A is a cross-sectional view of the electrode parts and FIG. 2B is a cross-sectional view of coated active material particles.
  • a lithium ion secondary battery (also simply referred to as LIB) 1 has a battery assembly 2 in which an electrode stack 5 is housed in an outer casing 3, as shown in FIG. 1, and the outer casing 3 of the battery assembly 2 is filled with an electrolytic medium 6 and sealed.
  • the electrolytic medium 6 may be a nonaqueous electrolyte LIB, which is a nonaqueous electrolyte, or the electrolytic medium 6 may be an all-solid-state LIB, which is a solid electrolyte, or the electrolytic medium 6 may be a polymer LIB, which is a polymer electrolyte, and is preferably a nonaqueous electrolyte LIB.
  • the lithium ion secondary battery 1 contains a non-aqueous electrolyte LIB.
  • the exterior body 3 is not particularly limited as long as it has an internal space, can accommodate and seal the electrode stack 5 and the electrolytic medium 6 in the internal space, is chemically stable against the electrolytic medium 6, and has water vapor barrier properties.
  • the exterior body 3 can be a can made mainly of aluminum, iron, or stainless steel, or a laminate film containing a laminate resin.
  • the positive electrode section 10 is an intercalation electrode in which a positive electrode active material layer 21 is laminated on at least one main surface of a positive electrode current collector 20 and Li ions can be inserted and removed.
  • the positive electrode part 10 of this embodiment has positive electrode active material layers 21 laminated on both main surfaces of a positive electrode current collector 20 .
  • the negative electrode portion 11 is an intercalation electrode in which a negative electrode active material layer 121 is laminated on at least one main surface of a negative electrode current collector 120, and in which the negative electrode active material layer 121 is laminated on the negative electrode current collector 120. Li ions can be inserted and removed.
  • the negative electrode part 11 has a negative electrode active material layer 121 laminated on both main surfaces of a negative electrode current collector 120, similar to the positive electrode part 10 shown in FIG. 2(a).
  • the current collectors 20 and 120 are electrically conductive plate-like or film-like bodies, and are not particularly limited as long as they are electrically conductive.
  • the current collectors 20, 120 can be made of, for example, aluminum or an aluminum alloy. Aluminum or an aluminum alloy is preferable because it is stable in a reactive atmosphere, and a coating in which a metal surface is coated with a metal that does not react at the potential of the positive or negative electrode can be used.
  • the active material layer 21, 121 is a Li ion conductive active material, and as shown in the enlarged view of FIG. 2(a), includes a plurality of coated active material particles 30, 130, binders 70, 70, a conductive network 80, 80 and a permeable pore network 81, 81.
  • the active material layers 21 and 121 preferably include a solid electrolyte interphase (SEI) structure.
  • SEI solid electrolyte interphase
  • the active material layer 21, 121 is a sea-island structure film, and is a bulk film having a cross-sectional shape including island-like portions 60 and sea-like portions 61. It is.
  • the active material layer 21, 121 is dominated by the coated active material particles 30, 130 in terms of weight ratio, but the binder 70 and conductive network 80 make up a large proportion of the active material layer 21, 121, which can be seen even with an electron microscope.
  • the coated active material particle 30 includes a core-shell particle 36 having a core-shell structure with a positive electrode active material particle 40 as a core and a shell film 41 as a shell. That is, in the core-shell particle 36 , the outer surface of the positive electrode active material particle 40 is covered with a shell film 41 .
  • the coated active material particle 30 of this embodiment further includes a buffer portion 42 on a part or all of the outer surface of the shell film 41. That is, in the coated active material particle 30 of this embodiment, the surface of the positive electrode active material particle 40 is covered with a coating 35, and the coating 35 is a multilayer film of the shell film 41 and the buffer portion 42.
  • the relative Li ion content of the shell film 41 of the coated active material particle 130 constituting the negative electrode active material layer 121 is different from the relative Li ion content of the shell film 41 of the coated active material particle 30 constituting the positive electrode active material layer 21.
  • the positive electrode shell film Li ion concentration which is the concentration of Li ions contained in the shell film 41 of the coated active material particle 30, is different from the negative electrode shell film Li ion concentration, which is the concentration of Li ions contained in the shell film 41 of the negative electrode active material particle 140.
  • the positive electrode shell film Li ion concentration and the negative electrode shell film Li ion concentration are average concentrations in the film.
  • the positive electrode active material particles 40 are lithium transition metal composite oxide particles, and are capable of inserting and desorbing Li ions.
  • the positive electrode active material particles 40 preferably have an average potential for desorption and insertion of Li ions of 4.5 V or more and 5.0 V or less with respect to the deposition potential of lithium metal (also indicated as vs. Li + /Li). That is, the positive electrode active material particles 40 preferably have an operating potential of 4.5 V or more and 5.0 V or less relative to lithium metal when used alone.
  • the potential hereinafter also referred to as voltage) (vs.
  • the positive electrode active material particles 40 are not particularly limited, but are preferably a spinel-type lithium manganese oxide represented by the following formula (1). Li 1+x M y Mn 2-x-y O 4 ...(1) In the formula (1), x and y satisfy 0 ⁇ x ⁇ 0.2 and 0 ⁇ y ⁇ 0.8, respectively, and M is at least one selected from the group consisting of Al, Mg, Zn, Ni, Co, Fe, Ti, Cu, and Cr.
  • lithium nickel manganese oxide in which M is Ni, is preferred.
  • lithium titanate for the negative electrode active material particles 140, since lithium deposition is less likely to occur and safety is improved.
  • the negative electrode active material particles 140 are particularly preferably lithium titanate having a spinel structure, from the viewpoint of small expansion and contraction of the active material during the reaction of inserting and extracting Li ions.
  • Lithium titanate may contain trace amounts of elements other than lithium and titanium, such as Nb.
  • the particle size of the active material particles 40, 140 is not particularly limited, but the median diameter d50 is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, and even more preferably 20 ⁇ m or more.
  • the positive electrode active material particles 40, 140 preferably have a median diameter d50 of 100 ⁇ m or less, more preferably 80 ⁇ m or less, further preferably 50 ⁇ m or less, and particularly preferably 30 ⁇ m or less.
  • the shell film 41 is a film having a continuous layer structure that densely covers the surface shape of the active material particles 40, 140, and is a coating made of a Li ion conductive oxide that contains phosphorus as an element.
  • the shell film 41 constituting the coated active material particle 30 is preferably made of an intercalation material that functions as a positive electrode active material by itself.
  • Shell film 41 contains a phosphate ion-containing lithium compound that contains phosphate ions and further contains one or more metals (metal species) selected from the group consisting of Fe, Mn, Si, and Al.
  • the lithium compound containing phosphate ions lithium phosphate compounds such as lithium manganese phosphate (hereinafter also referred to as LMP) and lithium iron phosphate (hereinafter also referred to as LFP) having an olivine type crystal structure, lithium titanium aluminum phosphate (hereinafter also referred to as LATP) and lithium phosphate (hereinafter also referred to as LP) having a NASICON type crystal structure are preferred, and lithium transition metal phosphates such as LMP, LFP, and LATP are preferred.
  • LMP lithium manganese phosphate
  • LFP lithium iron phosphate
  • LTP lithium titanium aluminum phosphate
  • LP lithium phosphate
  • lithium transition metal phosphates such as LMP, LFP, and LATP are preferred.
  • the shell film 41 is LMP, which is a lithium compound film containing manganese (Mn) elements and containing phosphate ions.
  • shell film 41 has different metals and/or compositions on both sides and has a two-layer structure of LFP/LMP from the center of active material particle 40, 140 toward the outside. It is more preferable that the constituent transition metal of shell film 41 gradually changes from Fe to Mn. It is further preferable that the shell film 41, together with the buffer portion 42, changes the composition and/or ratio of the metals in the Li-based polyanion.
  • the thickness of shell film 41 is thinner than the particle diameter of the Li ion conductive oxide, and is preferably 5 nm or more and 20 nm or less, and more preferably 5 nm or more and 15 nm or less. Within this range, the amount of gas generated can be suppressed while suppressing the resistance loss in shell film 41 .
  • the shell film 41 covers at least a portion of the surface of the active material particles 40, 140, more preferably covers 95% or more, and preferably covers the surface completely.
  • the shell film 41 is preferably amorphous from the viewpoint of replenishing Li ions of the active material particles 40, 140 consumed by the SEI structure of the buffer section 42 described later.
  • the buffer portion 42 is a silicon-containing compound film that contains lithium element and further contains silicon element.
  • the buffer portion 42 has a solid electrolyte interface (hereinafter also referred to as SEI) structure generated by an electrochemical reaction between the core-shell particles 36 and the interface electrolyte, and is a siloxane-modified coating layer containing silicon element.
  • SEI solid electrolyte interface
  • the buffer section 42 is a selectively permeable membrane that allows only Li ions to pass through and does not allow electrons to pass through.
  • the buffer section 42 is an insertion/destruction prevention layer that prevents the structure of the core-shell particles 36, 136 from being destroyed by insertion of organic solvent molecules with a large molecular weight, which move together with Li ions in the electrolytic medium 6, into the core-shell particles 36, particularly into the Li ion insertion/desorption sites of the active material particles 40, 140.
  • the buffer portion 42 preferably includes a modified region that is inseparably integrated with the SEI structure at the surface near the interface with the core-shell particle 36, 136, particularly at the contact portion with the permeable pore network 81.
  • the buffer portion 42 may contain, in addition to lithium and silicon elements, a metal oxide and/or a metal phosphate.
  • the buffer portion 42 covers at least a portion of the surface of the core-shell particle 36 , 136 .
  • Buffer portions 42 are formed and distributed on the outer surface of shell film 41, and coating 35 preferably differs between both surfaces of shell film 41 in at least one of the phosphate ion concentration, the metal species concentration, and the composition. It is preferable that the average occupancy rate of buffer portion 42 relative to the outer surface of shell film 41 per active material particle 40, 140 is 0.1% or more and 30% or less.
  • the active material layer 21, 121 can be formed in which the core-shell particles 36, 136 are bonded with sufficient adhesive strength, and a stable low-resistance conductive network 80 can be configured. Furthermore, sufficient adhesive strength can be obtained with respect to the current collector 20, 120. In addition, the active material layer 21, 121 can be given the strength to support the active material particles 40, 140 and the core-shell particles 36, 136 as an integral layer, a stable low-resistance conductive network 80 can be formed, and the adhesive strength with the current collector 20, 120 can be made sufficient.
  • the conductive network 80 is composed of a conductive material such as a conductive assistant, and is preferably composed of a conductive carbon material, and more preferably at least one selected from natural graphite, artificial graphite, vapor-grown carbon fiber, carbon nanotubes, acetylene black, ketjen black, and furnace black.
  • the amount of the conductive material constituting the conductive network 80 contained in the active material layer 21, 121 is preferably 1 part by weight or more and 30 parts by weight or less per 100 parts by weight of the core-shell particles 36, 136. Within this range, the electrical conductivity of the electrode parts 10, 11 can be ensured while maintaining the adhesiveness to the binder 70.
  • the electrical conductivity with the current collectors 20, 120 can be made sufficient while obtaining sufficient adhesiveness with the current collectors 20, 120.
  • At least a portion of the conductive network 80 contacts the core-shell particles 36 , 136 and extends outward from the contact portion with the core-shell particles 36 , 136 . That is, conductive network 80 has a conductive network cell contact portion that contacts shell film 41 .
  • the island-shaped portion 60 is composed of the coated active material particles 30 ( 130 ), a binder 70 , and a conductive network 80 .
  • the island-shaped portion 60 is longer than the conductive paths between adjacent coated active material particles 30, 30 (130, 130), and has a chain-like conductive network 80 as its main skeleton, with the binder 70 supporting the state in which multiple coated active material particles 30 (130) are in contact with this conductive network 80.
  • a conductive network 80 which resembles a long chain, mainly composed of a conductive material, rather than by the conductive paths between the coated active material particles 30, 30 (130, 130), and at least a part of the conductive network 80 is exposed on the surface of the active material layer 21 (121).
  • the reason why a structure is formed in which the binder 70 supports a state in which multiple coated active material particles 30 (130) are in contact with such a conductive network 80 is that, when produced by the manufacturing method described below, in the slurry formed in the paste application process, the coated active material particles 30 (130) with hydrophilic surfaces are lined up in a hydrophobic medium containing a conductive material (conductive assistant), binder 70, and solvent, and then, by drying and removing the solvent, the coated active material particles are supported by the binder 70.
  • a conductive material conductive assistant
  • the ocean-like portion 61 is composed of a permeable pore network 81 as shown in FIG. 2( a ).
  • the permeable pore network 81 has a plurality of pores, which are interconnected to allow the electrolytic medium 6 to permeate therethrough. It is preferred that the permeating pore network 81 has some of its pores extending to and contacting the core-shell particles 36 (136).
  • the permeable pore network 81 preferably comprises a pore-shell contact portion that contacts the shell membrane 41 via the buffer portion 42 .
  • the permeable pore network 81 has a non-liquid Li ion conductor having an SEI structure disposed at least in the contact portion (pore shell contact portion).
  • the Li ion conductor preferably contains one or more metal elements selected from the group consisting of Mn, Fe, Al and Si.
  • the buffer portion 42 is preferably formed from the pore shell contact portion to the conductive network 80 .
  • the conductive network-cell contact portion which is the contact portion between the conductive network 80 and the shell film 41, is preferably held between two adjacent pore-shell contact portions on the surface of the active material particles 40, 140.
  • the permeable pore network 81 is a cavity formed by the contours of the coated active material particles 30, the binder 70, and the conductive network 80, and is three-dimensionally continuous from the current collector 20 (120) side (inside) to the outside.
  • the ratio of the total area of pores to the area of the surface is preferably 0.1% or more and 30% or less, and more preferably 1% or more and 10% or less.
  • the permeable pore network 81 is in contact with the active material particles 40 (140) or the shell membrane 41, and at least during charging and discharging of the lithium ion secondary battery 1, a portion of the electrolytic medium 6 permeates therethrough, and it is preferable that a non-liquid Li ion conductor including an SEI structure is formed in the contact portion of the permeable pore network 81.
  • This non-liquid Li ion conductor having an SEI structure preferably contains one or more metal elements selected from the group consisting of Mn, Si, Fe, and Al, and more preferably contains Mn and Si.
  • the separator 12 is disposed between the positive electrode part 10 and the negative electrode part 11 and has a structure that is insulating and can contain the electrolytic medium 6 .
  • the separator 12 include woven fabrics, nonwoven fabrics, and microporous membranes made of nylon, cellulose, polysulfone, polyethylene, polypropylene, polybutene, polyacrylonitrile, polyimide, polyamide, polyethylene terephthalate, and combinations of two or more of these.
  • the separator 12 may contain various plasticizers, antioxidants, and flame retardants, and may be coated with metal oxides or the like.
  • the positive electrode extraction member 13 is a positive electrode terminal that is connected to one or more positive electrode parts 10 and can be connected to an external load, and is provided across the inside and outside of the exterior body 3 .
  • the negative electrode extraction member 14 is a negative electrode terminal that is connected to one or more negative electrode parts 11 and can be connected to an external load, and is provided across the inside and outside of the exterior body 3 .
  • the electrolytic medium 6 is an electrolytic solution, a polymer electrolyte, or a solid electrolyte, and is preferably a nonaqueous electrolytic solution in which a solute is dissolved in a nonaqueous solvent, or a polymer electrolyte in which a polymer is impregnated with a nonaqueous electrolytic solution in which a solute is dissolved in a nonaqueous solvent, and more preferably a nonaqueous electrolytic solution.
  • the non-aqueous solvent used in the electrolytic medium 6 preferably contains a cyclic aprotic solvent and/or a chain aprotic solvent.
  • cyclic aprotic solvents include cyclic carbonates, cyclic esters, cyclic sulfones, and cyclic ethers. From the viewpoint of forming a high-quality SEI structure, a cyclic carbonate-based compound containing an unsaturated bond or a halogen atom may be used.
  • a solvent generally used as a solvent for a nonaqueous electrolyte such as a chain carbonate, a chain carboxylate ester, a chain ether, or acetonitrile, may be used.
  • a chain carbonate-based compound containing an unsaturated bond or a halogen atom may be used.
  • aprotic solvents that can be used include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, ⁇ -butyrolactone, 1,2-dimethoxyethane, sulfolane, dioxolane, and methyl propionate.
  • These solvents may be used alone or in combination of two or more kinds. However, it is preferable to use a solvent in combination of two or more kinds in view of the ease of dissolving the solute described below and the high conductivity of Li ions.
  • a mixture of one or more kinds of chain carbonates exemplified by dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, and methyl propyl carbonate and one or more kinds of cyclic compounds exemplified by ethylene carbonate, propylene carbonate, butylene carbonate, and ⁇ -butyrolactone is preferred, since this has high stability at high temperatures and high lithium conductivity at low temperatures.
  • a mixture of one or more chain carbonates exemplified by dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate and one or more cyclic carbonates exemplified by ethylene carbonate, propylene carbonate, and butylene carbonate is particularly preferred.
  • the electrolytic medium 6 may further contain a silicon-containing compound as an additive.
  • silicon-containing compounds include siloxane compounds, silazane compounds, and silylamide compounds each containing one or more unsaturated groups.
  • cyclic siloxanes having a vinyl group such as 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (4VC4S), are preferred.
  • Siloxane-based compounds containing one or more unsaturated groups contain at least one siloxane bond and one or more carbon double bonds, and it is believed that the siloxane bond sites can conduct Li ions, and the carbon double bond sites can contribute to the formation of an SEI structure through cross-linking.
  • the electrolytic medium 6 when the electrolytic medium 6 is a polymer electrolyte, the electrolytic medium 6 can be made of PEG, PEO, PAn, PVDF, a fluoropolymer, or a polymer grafted with a (meth)acrylic polymer.
  • the electrolytic medium 6 is preferably a ceramic electrolyte containing lithium element
  • the electrolyte that can be used include sulfide-based solid electrolytes such as Li10GeP2S12 ( LGPS ), Li7P3S11 , and 70Li2S - 30P2S5 , perovskite-type solid electrolytes such as (Li , La) TiO3 , and NASICON-type solid electrolytes such as LATP.
  • the coated active material forming step is a step of forming the coated active material particles 30, 130.
  • the coated active material forming step is mainly composed of an active material particle preparing step, a shell film forming step, and a paste applying step.
  • the active material particle preparation step is a step of preparing the active material particles 40, 140.
  • the shell film forming step is a step of forming shell films 41, 41 which are phosphate ion-containing lithium compound films on the surfaces of active material particles 40, 140.
  • the shell film formation process for forming the shell film 41 on the positive electrode active material particles 40 involves first pulverizing a lithium compound containing phosphate ions with a pulverizing device such as a ball mill to form particles of the lithium compound containing phosphate ions (pulverizing process).
  • the phosphate ion-containing lithium compound before the pulverization step is preferably a Li ion conductive oxide containing phosphorus, and more preferably a phosphate-based compound having an olivine type crystal structure. It is preferable that the particles of the phosphate ion-containing lithium compound after the pulverization step have a partially destroyed crystal structure and are entirely or partially amorphous (non-crystalline).
  • the particles of the phosphate ion-containing lithium compound after the pulverization step preferably have a BET specific surface area of 20 m 2 /g or more and 80 m 2 /g or less.
  • the particles of the phosphate ion-containing lithium compound after the pulverization step preferably have a BET specific surface area equivalent diameter (dBET) of 30 nm or more, more preferably 50 nm or more.
  • the particles of the phosphate ion-containing lithium compound after the pulverization step preferably have a BET specific surface area equivalent diameter (dBET) of 500 nm or less, more preferably 450 nm or less.
  • the particles of the lithium compound containing phosphate ions are pulverized in a pulverization process, and the resulting fine particles are dispersed in a dispersion solvent to form a fine particle fluid (fine particle fluid formation process).
  • the dispersion solvent used in this case is preferably one or more alcohol solutions, and more preferably ethanol from the viewpoints of volatility and safety.
  • the fine particle fluid formed at this time is a transparent sol in a sol state and has fluidity.
  • the microparticle fluid is ground into active material particles 40 by a grinding device such as a grinding mill to form a ground product (ground product formation step).
  • the amount of the particles of the lithium compound containing phosphate ions put into the grinding device is preferably 0.5 wt % or more.
  • the amount of the particles of the lithium compound containing phosphate ions put into the grinding device is preferably 2.5 wt % or less, more preferably 1.6 wt % or less, and particularly preferably 1 wt % or less.
  • the treatment temperature in the milling device is preferably 5°C or higher and 100°C or lower, more preferably 8°C or higher and 80°C or lower, and even more preferably 10°C or higher and 50°C or lower.
  • the treatment time in the milling device is preferably from 5 to 90 minutes, and more preferably from 10 to 60 minutes.
  • the atmosphere in the milling apparatus at this time is preferably an inert gas atmosphere or an air atmosphere.
  • the ground material is subjected to a heat treatment to remove the dispersion solvent from the ground material, forming a shell film 41, and forming the core-shell particles 36 (removal process).
  • the heat treatment temperature at this time is preferably 300° C. or higher, and more preferably 350° C. or higher. If the heat treatment temperature is below 300° C., the adhesion between the active material particles 40 and the shell film 41 will be insufficient, and the shell film 41 may peel off during charging and discharging of the battery, which may lead to a decrease in the long-term reliability of the battery. On the other hand, if the heat treatment temperature is too high, the crystal structure of shell film 41 may change, causing a decrease in Li ion conductivity and preventing normal charging and discharging of the battery. Therefore, the heat treatment temperature is preferably 850° C. or less, and more preferably 500° C. or less from the viewpoint of suppressing crystallization of the amorphous portion of shell film 41.
  • the heat treatment time is preferably 30 minutes or more, more preferably 45 minutes or more, and is preferably 180 minutes or less, more preferably 150 minutes or less.
  • the shell film formation step of forming shell film 41, which is a phosphate ion-containing lithium compound film, on the surface of positive electrode active material particle 40 is similar to that of the first embodiment except that negative electrode active material particle 140 is used instead of positive electrode active material particle 40, and therefore a description thereof will be omitted. That is, the shell film formation step of forming shell film 41 on positive electrode active material particle 40 and the shell film formation step of forming shell film 41 on negative electrode active material particle 140 are basically the same, with the difference being whether the core is positive electrode active material particle 40 or negative electrode active material particle 140.
  • the paste application process is a process in which active material particles 40, 140 (core-shell particles 36, 136) on which shell films 41, 41 are formed are mixed with a conductive material, a binder 70, and optionally a silicon-containing compound, dispersed in a solvent to form a paste-like slurry, and the slurry is applied to a current collector 20, 120 to form a paste-coated current collector.
  • the solvent used in this process is not particularly limited as long as it can dissolve or disperse the core-shell particles 36, 136 and the conductive material that constitutes the conductive network 80, and the binder 70.
  • NMP N-methyl-2-pyrrolidone
  • dimethylformamide dimethylacetamide
  • methyl ethyl ketone methyl acetate
  • ethyl acetate methyl acetate
  • tetrahydrofuran can be used.
  • Dispersants and thickeners may also be added to these.
  • the pasted current collector firing process is a process in which the pasted current collector is fired for a predetermined firing time at a predetermined firing temperature to form a work-in-progress positive electrode part containing positive electrode active material particles 40 and a work-in-progress negative electrode part containing negative electrode active material particles 140, respectively.
  • the firing temperature is not particularly limited as long as the paste-coated current collector is fired at the temperature at which the slurry solidifies, but is preferably, for example, 80° C. or higher and 200° C. or lower.
  • the solvent in the paste-coated collector is vaporized and removed, forming pores, and a permeable pore network 81 is formed in the in-progress positive electrode portion and in-progress negative electrode portion.
  • the battery assembly fabrication process is a process in which a part-time electrode laminate is placed inside the exterior body 3 to fabricate a part-time battery assembly.
  • the interface electrolyte may contain, in addition to the electrolytic medium 6, a vinyl group-containing cyclic compound such as 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (4VC4S). Siloxane may be added as an additive.
  • a vinyl group-containing cyclic compound such as 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (4VC4S).
  • Siloxane may be added as an additive.
  • the voltage application step is a step of applying a voltage between the positive electrode extraction member 13 and the negative electrode extraction member 14 of the in-progress electrode laminate.
  • the voltage application process causes the silicon-containing compound in the interface electrolyte to be laminated on the shell film 41 of the core-shell particles 36, 136 of the in-progress electrode laminate, forming a buffer section 42 including a modified region in which the SEI structure is modified by siloxane bonding, and forming an electrode laminate 5 having a positive electrode section 10 and a negative electrode section 11.
  • the voltage applied between the positive electrode extraction member 13 and the negative electrode extraction member 14 in this process is a voltage at which the silicon-containing compound in the interface electrolyte precipitates on the surface of the shell film 41, and is preferably 4.5 V or more and 5 V or less (vs. Li + /Li).
  • the electrolytic medium injection step is a step of discharging the interface electrolyte from inside the exterior body 3 as necessary and injecting the electrolytic medium 6 into the exterior body 3 of the battery assembly 2 .
  • the aging process is a process for checking the initial deterioration of the battery assembly 2, and is made up of an initial charging operation process and a curing operation process.
  • the initial charging operation step is a step of applying a voltage between the positive electrode take-out member 13 and the negative electrode take-out member 14 of the electrode laminate 5 to charge the electrode laminate 5 .
  • the curing step is a step of curing the exterior body 3 to seal the electrode laminate 5 and the electrolytic medium 6 .
  • the coating 35 that coats the active material particles 40, 140 contains a lithium compound containing phosphate ions, so that generation of gas due to decomposition of the electrolytic medium 6 can be suppressed.
  • the shell film 41 preferably contains one or more metals selected from the group consisting of Fe, Mn, Si, and Al, and more preferably the shell film 41 uniformly covers the active material particles 40, 140. In this manner, the area of contact between the active material particles 40, 140 and the electrolytic medium 6 is reduced, and generation of gas due to decomposition of the electrolytic medium 6 can be suppressed.
  • the positive electrode active material particles 40 are preferably made of a LiMn-based oxide and are coated with a shell film 41 of a phosphate-based compound that can also be used as a positive electrode active material. This makes it easier for the insertion and desorption reactions of Li ions to occur smoothly.
  • the positive electrode active material particles 40 are preferably made of a LiMn-based oxide containing nickel, for example, a LiMn-based oxide having a spinel crystal structure, which makes it possible to configure a high-capacity secondary battery capable of generating a high voltage.
  • the positive electrode active material particles 40 are preferably made of a layered rock salt type oxide, and more preferably made of a LiMn-based oxide having a Li-excess layered rock salt type structure. In this way, a secondary battery with even higher capacity can be constructed.
  • the negative electrode active material particles 140 are preferably made of a Li-titanium based oxide, which makes it possible to configure a secondary battery that is excellent in safety and reliability.
  • the negative electrode active material particles 140 are covered with a shell film 41 of a phosphate-based compound that can also be used as a positive electrode active material. This makes it easier for the insertion and desorption reactions of Li ions to occur smoothly, and a secondary battery with excellent characteristics can be constructed.
  • the vicinity of the interface between the shell film 41 and the active material particles 40, 140 is amorphous, so that the amorphous portion of the shell film 41 functions as a buffer even if a volume change occurs in the active material particles 40, 140 as charging and discharging proceeds. Therefore, the shell film 41, and in turn the coating 35, are less likely to crack or peel off.
  • a fine particle fluid in which fine particles, which are the raw material of the shell film 41, are dispersed in a dispersion solvent is ground into active material particles 40, 140 and heat-treated at a temperature of 100°C or higher and 500°C or lower, so that a high-quality, thin shell film 41 can be formed on the surface of the active material particles 40 while maintaining its amorphous state.
  • the shell films 41, 41 which are part of the coating 35 that covers the active material particles 40, 140, contain a lithium compound containing phosphate ions, so that gas generation due to decomposition of the electrolytic medium 6 can be further suppressed.
  • the shell film 41 contains a phosphate ion-containing lithium compound containing one or more metals selected from the group consisting of Fe, Mn, Si, and Al, so that the generation of gas due to decomposition of the electrolytic medium 6 can be suppressed.
  • the active material layers 21, 121 have a conductive network 80 and a permeable pore network 81, which facilitates the exchange of charges and lithium ions between the electrolytic medium 6 and the active material particles 40, 140, making it easier for electrode reactions to occur.
  • the permeable pore network 81 has a lithium ion conductor provided from the contact portion with the active material particles 40, 140 or the shell membrane 41, 41 toward the pores, so that the transfer of charges and lithium ions between the electrolytic medium 6 and the active material particles 40, 140 becomes smoother, and the electrode reaction occurs more easily.
  • the buffer section 42 has a silicon-containing compound film that contains elemental silicon, so the adhesion of the buffer section 42 is better and cracks and the like are less likely to occur.
  • the shell film 41 contains lithium elements, and the lithium in the shell film 41 can be used to replenish lithium that has been consumed for some reason, so performance is less likely to deteriorate.
  • the shell film 41 can suppress the elution of manganese element from the positive electrode active material particles 40 into the electrolytic medium 6, so performance is less likely to deteriorate.
  • the buffer section 42 is formed by injecting the interface electrolyte in the interface electrolyte injection process and applying a voltage between the positive electrode take-out member 13 and the negative electrode take-out member 14 in the voltage application process, but the present invention is not limited to this.
  • a silicon-containing compound containing elemental silicon may be added to the slurry in the paste application step, and buffer portion 42 may be formed in the paste-applied current collector firing step.
  • a paste containing a silicon-containing compound may be applied to the in-progress positive electrode part and the in-progress negative electrode part, and the paste may be solidified by heating, ultraviolet light, or the like to form the buffer part 42 .
  • the buffer section 42 may be formed by applying a paste containing a silicon-containing compound to the in-progress electrode laminate and solidifying it by heating, ultraviolet light, or the like.
  • a buffer section 42 is formed, but the present invention is not limited to this, and the buffer section 42 does not have to be formed.
  • the battery assembly creation process, the interface electrolyte injection process, and the voltage application process are omitted, and the electrolytic medium injection process is carried out after the battery assembly creation process.
  • LNMO spinel-type lithium nickel manganese oxide having a median diameter of 5 ⁇ m
  • 30 g of LNMO was put into a grinding mill (manufactured by Hosokawa Micron Corporation, product name: Nobilta), and while rotating with a clearance of 0.6 mm, rotor load power of 1.5 kW, and 2600 rpm, an ethanol dispersion slurry of LMP fine powder was added in two portions so that the amount of LMP fine powder added was 0.6 wt %.
  • the rotor rotation speed was kept in the range of 2600 rpm to 3000 rpm, and the mixture was treated at room temperature in an air atmosphere for 10 minutes to obtain LNMO whose surface was coated with LMP.
  • the obtained surface-coated LNMO was heat-treated at 350° C. for 1 hour to obtain a positive electrode composite active material.
  • NMP N-methyl-2-pyrrolidone
  • the binder was prepared by adjusting the solid concentration to 5% by weight in N-methyl-2-pyrrolidone (NMP), and NMP was further added to adjust the viscosity to facilitate coating, as described below.
  • the slurry was applied to 20 ⁇ m aluminum foil and then dried in an oven at 120°C. This procedure was performed on both sides of the aluminum foil, and then the foil was further vacuum dried at 170°C to produce a positive electrode.
  • the slurry was applied to 20 ⁇ m aluminum foil and then dried in an oven at 120° C. This procedure was repeated on both sides of the aluminum foil, and the foil was then further vacuum dried at 170° C. to produce a negative electrode.
  • a battery was prepared by the following procedure using the positive and negative electrodes prepared in (i) and (ii) above and a 20 ⁇ m polypropylene separator. First, the positive and negative electrodes were dried under reduced pressure at 80° C. for 12 hours. Next, 15 positive electrodes and 16 negative electrodes were stacked in the order of negative electrode/separator/positive electrode. The outermost layers were both separators. Next, aluminum tabs were vibration-welded to the positive and negative electrodes at both ends.
  • Two sheets of aluminum laminate film were prepared as exterior materials, and a depression to become a battery portion and a depression to become a gas collecting portion were formed by pressing, after which the electrode laminate was inserted.
  • the unsealed portion was heat-sealed at 180° C. for 7 seconds while reducing the pressure.
  • the obtained battery was charged at a constant current of 0.2 C until the battery voltage reached a cut-off voltage of 3.4 V, and then the charging was stopped. After that, the battery was left to stand in an environment of 60° C. for 24 hours, and then discharged at a constant current of 0.2 C. The discharge was stopped when the battery voltage reached 2.5 V. After the discharge was stopped, the gas accumulated in the gas collector was removed and the battery was resealed.
  • a lithium ion secondary battery for evaluation was produced by the above operations.
  • Example 6 (Experimental Example 6) ( i) In the preparation of the positive electrode, Li1.3Al0.3Ti1.7 ( PO4 ) 3 (hereinafter also referred to as LATP) was used instead of LMP, and the coating amount of the LATP fine powder was adjusted to 1.2 wt %, except that the same procedure was followed as in Example 4, and this was designated as Example 6.
  • the LATP fine powder was prepared by the following method. As starting materials , Li2CO3 , AlPO4 , TiO2 , NH4H2PO4 , and ethanol as a solvent were mixed in a predetermined amount, and treated with a planetary ball mill at 150 G for 1 hour using zirconia balls with a diameter of 3 mm. After removing the zirconia balls from the treated mixture with a sieve, the mixture was dried at 120°C to remove the ethanol. Then, the mixture was treated at 800°C for 2 hours to obtain LATP fine powder.
  • the rotor rotation speed was kept in the range of 2600 rpm to 3000 rpm, and the mixture was treated at room temperature in an air atmosphere for 10 minutes to obtain LTO whose surface was coated with LMP.
  • the obtained surface-coated LTO was heat-treated at 350° C. for 1 hour to obtain a negative electrode composite active material.
  • NMP N-methyl-2-pyrrolidone
  • the binder was prepared by adjusting the solid concentration to 5% by weight in N-methyl-2-pyrrolidone (NMP), and NMP was further added to adjust the viscosity to facilitate coating, as described below.
  • the slurry was applied to an aluminum foil having a thickness of 20 ⁇ m, and then dried in an oven at 120° C. This operation was performed on both sides of the aluminum foil, and then the aluminum foil was further dried in a vacuum at 170° C. to prepare a negative electrode.
  • Experimental Example 14 the same procedure as in Experimental Example 6 was followed, and this was designated Experimental Example 14.
  • the weight of the lithium-ion secondary battery was measured using an electronic balance.
  • the weight in water was measured using a specific gravity meter (Alpha Mirage, product number: MDS-3000), and the buoyancy was calculated by taking the difference between these weights.
  • the volume of the lithium-ion secondary battery was calculated by dividing this buoyancy by the density of water (1.0 g/cm3).
  • the amount of gas generated was calculated by comparing the volume after aging with the volume after the cycle characteristic evaluation described below.
  • the lithium ion secondary batteries produced in each of Experimental Examples 1 to 18 were charged and discharged at 25° C. and 0.2 C, and then continuously charged and discharged at 2.0 C to evaluate the rate characteristics.
  • the end-of-charge voltage and the end-of-discharge voltage were set to 2.5 V and 3.4 V, respectively.
  • the ratio of the discharge capacity at 2.0 C to the discharge capacity at 0.2 C was defined as the discharge rate characteristic.
  • the amount of gas generation can be suppressed by coating the surface of the active material particles with a film containing a lithium compound containing phosphate ions.
  • the amount of gas generated can be suppressed and the rate characteristics are improved.

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JP2022022256A (ja) * 2016-05-27 2022-02-03 Ｄｏｗａエレクトロニクス株式会社 正極活物質粉体
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JP2022154600A (ja) * 2021-03-30 2022-10-13 株式会社カネカ リチウムイオン二次電池用負極活物質、及び、その製造方法

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JP2018116856A (ja) * 2017-01-19 2018-07-26 トヨタ自動車株式会社 リチウムイオン二次電池用正極活物質
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