WO2023013585A1 - リチウムイオン二次電池用負極およびリチウムイオン二次電池 - Google Patents

リチウムイオン二次電池用負極およびリチウムイオン二次電池 Download PDF

Info

Publication number
WO2023013585A1
WO2023013585A1 PCT/JP2022/029504 JP2022029504W WO2023013585A1 WO 2023013585 A1 WO2023013585 A1 WO 2023013585A1 JP 2022029504 W JP2022029504 W JP 2022029504W WO 2023013585 A1 WO2023013585 A1 WO 2023013585A1
Authority
WO
WIPO (PCT)
Prior art keywords
negative electrode
active material
electrode active
positive electrode
ion secondary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2022/029504
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
巧 日浅
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Priority to JP2023540333A priority Critical patent/JP7718490B2/ja
Priority to CN202280053937.8A priority patent/CN117795732A/zh
Publication of WO2023013585A1 publication Critical patent/WO2023013585A1/ja
Priority to US18/425,790 priority patent/US20240170682A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/80—Porous plates, e.g. sintered carriers
    • H01M4/801—Sintered carriers
    • H01M4/803—Sintered carriers of only powdered material
    • 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
    • H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
    • 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
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0002—Aqueous electrolytes
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • 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

  • This technology relates to negative electrodes for lithium ion secondary batteries and lithium ion secondary batteries.
  • This lithium ion secondary battery includes a positive electrode, a negative electrode, and an aqueous electrolytic solution, and the aqueous electrolytic solution is an electrolytic solution containing an aqueous solvent.
  • Various studies have been made on technologies related to lithium ion secondary batteries equipped with an aqueous electrolyte.
  • a negative electrode that is a sintered body of lithium titanate is used, and the average pore diameter, specific surface area and relative density of the negative electrode are specified.
  • a negative electrode that is a sintered body of an oxide containing lithium and a transition metal element is used, and the relative density of the negative electrode is specified (e.g. , see Patent Document 2).
  • a negative electrode that is a titanium-titanium oxide composite electrode is used, and the negative electrode contains anatase-type titanium oxide having a nanotube shape (for example, Patent Document 3 reference.).
  • a negative electrode containing titanium oxide is used in a secondary battery having an aqueous electrolyte (see, for example, Patent Document 4).
  • a negative electrode for a lithium ion secondary battery and a lithium ion secondary battery capable of obtaining excellent operating characteristics are desired.
  • a negative electrode for a lithium ion secondary battery absorbs and releases lithium ions and includes a negative electrode active material layer.
  • the negative electrode active material layer includes a plurality of negative electrode active material particles and has a porous structure in which the plurality of negative electrode active material particles are directly bonded to each other.
  • Each of the plurality of negative electrode active material particles contains anatase-type titanium oxide, and the average particle size of the plurality of negative electrode active material particles is 100 nm or less.
  • a lithium ion secondary battery of an embodiment of the present technology includes a positive electrode that absorbs and releases lithium ions, a negative electrode, and an electrolytic solution containing an aqueous solvent, and the negative electrode is the above-described lithium ion secondary battery of the embodiment of the present technology. It has a configuration similar to that of a negative electrode for a lithium ion secondary battery.
  • the average particle size of a plurality of negative electrode active material particles is calculated based on the observation results (electron micrograph) of the negative electrode active material layer observed using an electron microscope.
  • the definition of the "average particle size”, that is, the details of the procedure for calculating the average particle size based on the electron micrograph will be described later.
  • the negative electrode active material layer has a porous structure in which a plurality of negative electrode active material particles are directly bonded to each other.
  • Each of the plurality of negative electrode active material particles contains anatase-type titanium oxide, and the average particle size of the plurality of negative electrode active material particles is 100 nm or less, so excellent operating characteristics can be obtained.
  • FIG. 2 is an enlarged cross-sectional view showing the structure of the negative electrode shown in FIG. 1;
  • FIG. 3 is a schematic diagram showing an electron microscope photograph of a cross section of the negative electrode active material layer shown in FIG. 2.
  • FIG. 4 is a cross-sectional view showing the configuration of a lithium-ion secondary battery of Modification 1.
  • FIG. 10 is a cross-sectional view showing the configuration of a lithium ion secondary battery of Modification 3; 10 is a cross-sectional view showing the configuration of a lithium-ion secondary battery of Modification 4.
  • FIG. 10 is a cross-sectional view showing the configuration of a lithium ion secondary battery of Modification 3.
  • First embodiment (lithium ion secondary battery) 1-1. Configuration 1-2. Operation 1-3. Manufacturing method 1-4. Action and effect 2 .
  • Second embodiment (lithium ion secondary battery) 2-1. Configuration 2-2. Operation 2-3. Manufacturing method 2-4. Action and effect 3. Modification 4. Applications of lithium-ion secondary batteries
  • negative electrode for a lithium ion secondary battery (hereinafter simply referred to as "negative electrode") of one embodiment of the present technology is a part (one component) of the lithium ion secondary battery, the negative electrode will be described together below.
  • the lithium-ion secondary battery described here is a secondary battery in which charge-discharge reactions proceed using the absorption and release of lithium ions, and includes a positive electrode, a negative electrode, and an aqueous electrolyte.
  • This aqueous electrolytic solution is a liquid electrolyte, and more specifically, an electrolytic solution containing an aqueous solvent as described above.
  • FIG. 1 shows the cross-sectional structure of the lithium ion secondary battery of the first embodiment
  • FIG. 2 is an enlarged cross-sectional structure of the negative electrode 30 shown in FIG.
  • FIG. 3 schematically shows an electron micrograph 100 of a cross section of the negative electrode active material layer 30B shown in FIG.
  • this lithium-ion secondary battery includes an exterior body 10, a positive electrode 20, a negative electrode 30, and an electrolytic solution 40.
  • the electrolytic solution 40 is lightly shaded.
  • the exterior body 10 is a substantially box-shaped exterior member that accommodates the positive electrode 20, the negative electrode 30, the electrolytic solution 40, and the like, and has an internal space S, as shown in FIG.
  • the exterior body 10 contains one or more of metal materials, glass materials, polymer compounds, and the like.
  • the exterior body 10 may be a rigid metal can, a glass case, a plastic case, or the like, or may be a soft (or flexible) metal foil, polymer film, or the like.
  • the positive electrode 20 is arranged in the internal space S, as shown in FIG. 1, and absorbs and releases lithium ions.
  • the positive electrode 20 includes a positive electrode current collector 20A having a pair of surfaces and positive electrode active material layers 20B provided on both surfaces of the positive electrode current collector 20A.
  • the positive electrode active material layer 20B may be provided only on one side of the positive electrode current collector 20A on the side where the positive electrode 20 faces the negative electrode 30 .
  • the positive electrode current collector 20A may be omitted. That is, since the positive electrode 20 does not include the positive electrode current collector 20A, only the positive electrode active material layer 20B is sufficient.
  • the positive electrode current collector 20A is a conductive support member that supports the positive electrode active material layer 20B, and is made of one or more of conductive materials such as metal materials, carbon materials, and conductive ceramic materials. contains. Specific examples of metallic materials include titanium, aluminum and their alloys. A specific example of the conductive ceramic material is indium tin oxide (ITO).
  • ITO indium tin oxide
  • the material forming the positive electrode current collector 20A preferably has insolubility, poor solubility, and corrosion resistance in the electrolytic solution 40, and has low reactivity with the positive electrode active material described later. .
  • the positive electrode current collector 20A preferably contains the metal material described above. This is because the positive electrode current collector 20A is less likely to deteriorate even when a lithium ion secondary battery is used.
  • the positive electrode current collector 20A may be a conductor whose surface is plated with the conductive material described above.
  • the material for forming the conductor is not particularly limited and can be arbitrarily selected.
  • connection terminal portion 20AT extends from the inside (internal space S) of the exterior body 10 to the outside.
  • the positive electrode active material layer 20B contains one or more of positive electrode active materials that occlude and release lithium ions. However, the positive electrode active material layer 20B may further contain one or more of a positive electrode binder, a positive electrode conductive agent, and the like.
  • the positive electrode active material contains a lithium-containing compound and the like, and the lithium-containing compound is a compound containing lithium as a constituent element.
  • the type of lithium-containing compound is not particularly limited, but specific examples include lithium composite oxides and lithium phosphate compounds.
  • a lithium composite oxide is an oxide containing lithium and one or more transition metal elements as constituent elements
  • a lithium phosphate compound is an oxide containing lithium and one or more transition metal elements. It is a phosphate compound containing as a constituent element.
  • the types of transition metal elements are not particularly limited, but specific examples include nickel, cobalt, manganese and iron.
  • lithium composite oxides having a layered rocksalt crystal structure include LiNiO 2 , LiCoO 2 , LiCo 0.98 Al 0.01 Mg 0.01 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi0.33Co0.33Mn0.33O2 , Li1.2Mn0.52Co0.175Ni0.1O2 and Li1.15 ( Mn0.65Ni0.22Co0.13 ) O2 .
  • _ _ _ _ _ _ A specific example of the lithium composite oxide having a spinel crystal structure is LiMn 2 O 4 and the like.
  • lithium phosphate compounds having an olivine-type crystal structure include LiFePO4 , LiMnPO4 , LiMn0.5Fe0.5PO4 , LiMn0.7Fe0.3PO4 and LiMn0.75Fe0.25PO4 .
  • the positive electrode binder contains one or more of synthetic rubber and polymer compounds.
  • the synthetic rubber include styrene-butadiene rubber
  • specific examples of the polymer compound include polyvinylidene fluoride and polyimide.
  • the positive electrode conductive agent contains one or more of conductive materials such as carbon materials, and specific examples of the carbon materials include graphite, carbon black, acetylene black, and ketjen black.
  • the conductive material may be a metal material, a conductive ceramic material, a conductive polymer, or the like.
  • the negative electrode 30 is arranged in the internal space S, as shown in FIG. 1, and intercalates and deintercalates lithium ions.
  • the negative electrode 30 includes a negative electrode current collector 30A having a pair of surfaces and negative electrode active material layers 30B provided on both surfaces of the negative electrode current collector 30A.
  • the negative electrode active material layer 30B may be provided only on one side of the negative electrode current collector 30A on the side where the negative electrode 30 faces the positive electrode 20 .
  • the negative electrode current collector 30A may be omitted. That is, since the negative electrode 30 does not include the negative electrode current collector 30A, only the negative electrode active material layer 30B is sufficient.
  • the negative electrode current collector 30A is a conductive support member that supports the negative electrode active material layer 30B, and is made of one or more of conductive materials such as metal materials, carbon materials, and conductive ceramic materials. contains. Specific examples of metal materials include stainless steel (SUS), titanium, tin, lead and their alloys. This stainless steel may be a highly corrosion-resistant stainless steel to which one or more of additive elements such as niobium and molybdenum are added. Specifically, the stainless steel may be SUS444 or the like to which molybdenum is added as an additive element. Details regarding the conductive ceramic material are as described above.
  • the material for forming the negative electrode current collector 30A preferably has insolubility, poor solubility, and corrosion resistance in the electrolytic solution 40, and has low reactivity with the negative electrode active material described later. . Therefore, the negative electrode current collector 30A preferably contains the metal material described above. This is because the negative electrode current collector 30A is less likely to deteriorate even when a lithium ion secondary battery is used.
  • the negative electrode current collector 30A may be a conductor whose surface is plated with the above-described conductive material.
  • the material for forming the conductor is not particularly limited and can be arbitrarily selected.
  • connection terminal portion 30AT extends from the inside (internal space S) of the exterior body 10 to the outside.
  • the negative electrode active material layer 30B contains a negative electrode active material that intercalates and deintercalates lithium ions. However, the negative electrode active material layer 30B may further contain a negative electrode conductor and the like. Details regarding the negative electrode conductive agent are the same as those regarding the positive electrode conductive agent.
  • the negative electrode active material layer 30B includes a plurality of particulate negative electrode active materials (hereinafter referred to as "a plurality of negative electrode active material particles 31"), Each of the plurality of negative electrode active material particles 31 is a so-called primary particle.
  • This negative electrode active material layer 30B has a porous structure, and the porous structure is formed by directly bonding a plurality of negative electrode active material particles 31 to each other. That is, in the negative electrode active material layer 30B, a plurality of voids (pores 32) are formed between the plurality of negative electrode active material particles 31 by directly bonding the plurality of negative electrode active material particles 31 to each other. . Thereby, the negative electrode active material layer 30B has a porous structure formed of the plurality of negative electrode active material particles 31 as described above.
  • the negative electrode active material layer 30B is a sintered body of the plurality of negative electrode active material particles 31 formed using a sintering method
  • the negative electrode active material layer 30B contains a plurality of negative electrode active material particles. 31 are joined directly to each other. The details of the method of forming the negative electrode active material layer 30B using this baking method will be described later.
  • the negative electrode active material layer 30B is a sintered body of a plurality of negative electrode active material particles 31, as described above. That is, the plurality of negative electrode active material particles 31 are directly connected to each other without the binder, rather than being indirectly connected to each other via the binder. In addition, since the plurality of negative electrode active material particles 31 are indirectly connected to each other via the conductive agent, they are not electrically connected to each other via the conductive agent, but rather are electrically connected to each other without the conductive agent. Since they are directly connected to each other, they are electrically connected to each other without the conductive agent.
  • the reason why the negative electrode active material layer 30B is a sintered body of the plurality of negative electrode active material particles 31 is that the plurality of negative electrode active material particles 31 are physically and electrically connected to each other. This is because the electron conductivity between the plurality of negative electrode active material particles 31 improves as the energy density increases. As a result, the electrical resistance of the negative electrode 30 is lowered while the energy density is ensured, so that a high discharge capacity can be easily obtained in the lithium-ion secondary battery.
  • each of the plurality of negative electrode active material particles 31 contains titanium oxide having an anatase crystal structure. This is because the anatase-type titanium oxide facilitates the stable progress of charging and discharging reactions in the strongly alkaline electrolytic solution 40 to be described later, as compared with titanium oxide having a rutile-type or brookite-type crystal structure. This makes it easier to stably obtain a higher discharge capacity in the lithium ion secondary battery.
  • each of the plurality of negative electrode active material particles 31 is a so-called nanoparticle. This is because lithium ions can easily move inside each negative electrode active material particle 31 . This is also because the energy density per unit weight of the negative electrode active material layer 30B is improved, and the plurality of pores 32 serving as lithium ion transfer paths are easily formed inside the negative electrode active material layer 30B. This makes it easier to obtain a higher discharge capacity in the lithium ion secondary battery.
  • the average particle size AS is preferably 30 nm or less. This is because the lithium ions can more easily move inside the negative electrode active material particles 31 . In addition, the energy density per unit weight of the negative electrode active material layer 30B is further improved, and the plurality of pores 32 are more likely to be formed inside the negative electrode active material layer 30B.
  • the lower limit of the average particle size AS is not particularly limited, specifically, the average particle size AS is 7 nm or more. This is because the plurality of negative electrode active material particles 31 can be stably formed easily.
  • the procedure for calculating the average particle diameter AS is as described below.
  • the electron micrograph 100 shown in FIG. 3 is used.
  • the negative electrode 30 is recovered by disassembling the secondary battery.
  • an electron micrograph 100 is obtained by observing the surface of the negative electrode active material layer 30B using an electron microscope.
  • the negative electrode 30 is cut using an ion milling device or the like to expose the cross section of the negative electrode active material layer 30B, and then the cross section of the negative electrode active material layer 30B is observed to obtain an electron micrograph. You can get 100.
  • an ion milling device ArBlade (registered trademark) 5000 manufactured by Hitachi High-Tech Co., Ltd. can be used.
  • FIG. 3 shows a case where each of the plurality of negative electrode active material particles 31 has a rectangular planar shape.
  • the negative electrode active material particle 31 present on the frontmost side is selected from among the plurality of negative electrode active material particles 31 overlapping each other. That is, the negative electrode active material particles 31 (31Y) whose entire outer edges are not visible because they overlap one or more other negative electrode active material particles 31 are not selected. On the other hand, the negative electrode active material particle 31 (31X) whose outer edge is entirely visible is selected because it does not overlap with the other one or two or more negative electrode active material particles 31 . In FIG. 3, some negative electrode active material particles 31X to be selected are shaded.
  • the average value is defined as the average particle size AS.
  • the negative electrode active material layer 30B is a sintered body of a plurality of negative electrode active material particles 31, and therefore has characteristic configuration conditions resulting from the sintered body.
  • the volume density of the negative electrode active material layer 30B is sufficiently high, specifically 1.0 g/cm 3 to 3.5 g/cm 3 .
  • the specific surface area of the negative electrode active material layer 30B is sufficiently large, specifically 1 m 2 /g to 500 m 2 /g, preferably 10 m 2 /g to 500 m 2 /g. This is because in the negative electrode 30, the energy density is sufficiently increased and the electric resistance is sufficiently decreased.
  • the procedure for measuring the specific surface area of the negative electrode active material layer 30B is as described below.
  • the negative electrode 30 is recovered by disassembling the lithium ion secondary battery.
  • the negative electrode 30 is washed using a washing solvent
  • the negative electrode 30 is sufficiently dried using a vacuum heating furnace.
  • an aqueous solvent such as pure water is used as the solvent, and the heating temperature is set at 60.degree. C. to 100.degree.
  • the specific surface area of the negative electrode active material layer 30B is measured using the BET method (nitrogen gas).
  • a fully automatic specific surface area measuring device Macsorb registered trademark manufactured by Mountec Co., Ltd. can be used.
  • the negative electrode active material layer 30B may further contain one or more of other negative electrode active materials that occlude and release lithium ions.
  • the types of other negative electrode active materials are not particularly limited, but specific examples include rutile-type titanium oxide, brookite-type titanium oxide, carbon materials, and metal-based materials.
  • This metal-based material is a material containing, as constituent elements, one or more of metal elements and metalloid elements capable of forming an alloy with lithium.
  • the negative electrode active material layer 30B contains another negative electrode active material, the following measures may be taken to calculate the average particle size AS.
  • the negative electrode active material layer 30B When examining whether the negative electrode active material layer 30B contains rutile-type or brookite-type titanium oxide as another negative electrode active material, the negative electrode active material layer 30B is analyzed using the X-ray diffraction method (XRD). This makes it possible to confirm the presence or absence of rutile-type or brookite-type titanium oxide based on the difference in crystal structure.
  • XRD X-ray diffraction method
  • the negative electrode active material layer 30B contains a carbon material or a metal-based material as another negative electrode active material
  • the negative electrode active material layer 30B is analyzed using energy dispersive X-ray analysis (EDX).
  • EDX energy dispersive X-ray analysis
  • elemental mapping can be used to confirm the presence or location of the carbon material or metal-based material.
  • the electrolytic solution 40 is accommodated in the internal space S, and is a water-based electrolytic solution as described above. That is, the electrolytic solution 40 is a solution in which an ionic substance that can be ionized in an aqueous solvent is dissolved or dispersed.
  • the lithium-ion secondary battery of the first embodiment is a so-called one-liquid type lithium-ion secondary battery because it includes one type of aqueous electrolyte (electrolyte 40).
  • the electrolytic solution 40 contains an aqueous solvent and one or more of ionic substances ionizable in the aqueous solvent. More specifically, the electrolytic solution 40 used in the lithium ion secondary battery contains lithium ions that are intercalated and deintercalated in each of the positive electrode 20 and the negative electrode 30 .
  • the type of aqueous solvent is not particularly limited, but specifically includes pure water and the like.
  • the type of ionic substance is not particularly limited, but specifically, one or more of acids, bases, electrolyte salts, and the like. Specific examples of acids include carbonic acid, oxalic acid, nitric acid, sulfuric acid, hydrochloric acid, acetic acid and citric acid.
  • the electrolyte salt is a salt containing cations and anions, more specifically, one or more of lithium salts.
  • lithium salts include lithium carbonate, lithium oxalate, lithium nitrate, lithium sulfate, lithium chloride, lithium acetate, lithium citrate, lithium hydroxide and imide salts.
  • the imide salts include bis(fluorosulfonyl)imidelithium and bis(trifluoromethanesulfonyl)imidelithium.
  • the electrolytic solution 40 used in the single-liquid type lithium ion secondary battery has a pH of 11 or higher, and therefore, as described above, preferably has strong alkalinity. This is because the lithium ions can easily move in the electrolytic solution 40, so that the charging/discharging reaction can easily proceed.
  • the electrolyte salt is preferably lithium hydroxide or the like. This is because the pH of the electrolytic solution 40 is likely to be 11 or more, so that the strongly alkaline electrolytic solution 40 can be easily and stably realized.
  • the content of the ionic substance, that is, the concentration (mol/kg) of the electrolytic solution 40 is not particularly limited and can be set arbitrarily. Specifically, the concentration of the electrolytic solution 40 is preferably 0.2 mol/kg to 4 mol/kg. This is because the strongly alkaline electrolytic solution 40 can be easily and stably realized.
  • the electrolyte salt may further contain one or more of the other metal salts in addition to the lithium salt described above.
  • the types of other metal salts are not particularly limited, but specific examples include alkali metal salts (excluding lithium salts), alkaline earth metal salts and transition metal salts. Specific examples of alkali metal salts include sodium salts and potassium salts, and specific examples of alkaline earth metal salts include calcium salts and magnesium salts.
  • the electrolytic solution 40 is more preferably a saturated solution of electrolyte salt. This is because lithium ions can be stably absorbed and released during charge/discharge, so that the charge/discharge reaction can proceed stably.
  • the internal space S is visually observed to determine whether or not the electrolyte salt is deposited. You should investigate whether When observing the internal space S, specifically, the inside of the electrolytic solution 40, the surface of the positive electrode 20, the inner wall surface of the exterior body 10, and the like are observed. Since the electrolyte salt is deposited, when the electrolyte solution 40 (liquid) and the electrolyte salt deposit (solid) coexist, the electrolyte solution 40 is considered to be a saturated solution of the electrolyte salt.
  • a surface analysis method such as X-ray photoelectron spectroscopy (XPS) may be used, or a composition analysis method such as inductively coupled plasma (ICP) emission spectroscopy may be used. may be used.
  • XPS X-ray photoelectron spectroscopy
  • ICP inductively coupled plasma
  • This lithium ion secondary battery operates as described below.
  • a mixture is obtained by mixing a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent with each other.
  • the composition of the mixture can be changed arbitrarily.
  • a paste-like positive electrode mixture slurry is prepared by putting the positive electrode mixture into the solvent.
  • This solvent may be an aqueous solvent or an organic solvent.
  • the cathode active material layer 20B is formed by applying the cathode mixture slurry to both surfaces of the cathode current collector 20A (excluding the connection terminal portion 20AT).
  • the positive electrode active material layer 20B may be compression-molded using a roll press machine or the like. In this case, the positive electrode active material layer 20B may be heated, or compression molding may be repeated multiple times. Thereby, the positive electrode 20 is produced.
  • a mixture is obtained by mixing a negative electrode active material and a negative electrode binder with each other.
  • the composition of the mixture can be changed arbitrarily.
  • one or more of the additives may be added to the mixture.
  • the types of additives are not particularly limited, but specific examples include surfactants and sintering aids.
  • the negative electrode active material As the negative electrode active material, as described above, a plurality of negative electrode active material particles 31 containing anatase-type titanium oxide and having an average particle size AS of 100 nm or less is used.
  • the type of the negative electrode binder is not particularly limited as long as it is one or more of the polymer compounds that are mixed with the negative electrode active material for the purpose of improving the strength of the powder compact described later.
  • Specific examples of polymer compounds include polyethylene glycol, polyvinyl alcohol and polyvinyl butyral.
  • the negative electrode binder is preferably a polymer compound that is decomposed and degreased at a temperature equal to or lower than the temperature at which anatase-type titanium oxide is baked.
  • Specific examples of surfactants include stearic acid, and specific examples of sintering aids include oxides of boron and oxides of silicon.
  • the granulated powder is press-molded together with the negative electrode current collector 30A.
  • Conditions such as press pressure can be arbitrarily set.
  • the granulated powder containing the plurality of negative electrode active material particles 31 is fixed on both surfaces of the negative electrode current collector 30A, so that a powder compact is obtained.
  • the powder compact is fired in the air.
  • Conditions such as sintering temperature and sintering time can be arbitrarily set according to the composition of the powder compact. In this case, conditions are adjusted so that the plurality of negative electrode active material particles 31 containing anatase-type titanium oxide are directly bonded to each other while maintaining the state of primary particles.
  • the maximum temperature during firing is 500°C to 1200°C.
  • the firing treatment may be performed in an oxygen atmosphere.
  • the negative electrode binder is degreased according to the baking, so that the plurality of negative electrode active material particles 31 are directly bonded to each other, and the plurality of pores are formed between the plurality of negative electrode active material particles 31 . 32 are formed.
  • the joined body (sintered body) of the plurality of negative electrode active material particles 31 is fixed to the surface of the negative electrode current collector 30A, so that the negative electrode active material layer 30B having a porous structure is formed.
  • the negative electrode 30 is produced.
  • the bonding state of the plurality of negative electrode active material particles 31 (plurality of primary particles) can be adjusted by appropriately adjusting the conditions such as the above-described pressing pressure, firing temperature, and firing time.
  • the volume density and specific surface area of the negative electrode active material layer 30B can be adjusted.
  • the method of firing the powder compact containing the negative electrode binder described above may not be used. If the negative electrode active material layer 30B is formed by directly bonding the plurality of negative electrode active material particles 31 to each other using the baking treatment, the procedure for forming the negative electrode 30 can be changed as appropriate. Specifically, a powder compact obtained by press-molding a plurality of negative electrode active material particles 31 without using a negative electrode binder may be fired. Further, a dispersion liquid in which a plurality of negative electrode active material particles 31 are dispersed is applied to the negative electrode current collector 30A, and after the dispersion liquid is dried, the negative electrode current collector 30A coated with the dispersion liquid is fired. may
  • connection terminal portions 20AT and 30AT are led out from the inside (internal space S) of the exterior body 10 to the outside.
  • electrolyte solution 40 is accommodated in the internal space S in which the positive electrode 20 and the negative electrode 30 are respectively arranged, a single liquid type lithium ion secondary battery using one type of aqueous electrolyte solution (electrolyte solution 40) is completed.
  • the negative electrode active material layer 30B of the negative electrode 30 contains a plurality of negative electrode active material particles 31, and the negative electrode active material layer 30B includes a plurality of negative electrode active material particles. 31 have a porous structure directly bonded to each other. Further, each of the plurality of negative electrode active material particles 31 contains anatase-type titanium oxide, and the average particle diameter AS of the plurality of negative electrode active material particles 31 is 100 nm or less.
  • the negative electrode 30 has a series of effects that will be described below.
  • the negative electrode active material layer 30B is a sintered body of a plurality of negative electrode active material particles 31, the plurality of negative electrode active material particles 31 are physically and electrically connected to each other.
  • the energy density of the negative electrode active material layer 30B is increased, and the electron conductivity between the plurality of negative electrode active material particles 31 is improved. Thereby, the electrical resistance is lowered while the energy density is ensured.
  • each of the plurality of negative electrode active material particles 31 contains anatase-type titanium oxide, the plurality of negative electrode active material particles 31 are stable against the strongly alkaline electrolyte 40 . As a result, the charging/discharging reaction can proceed stably and easily even when the strongly alkaline electrolyte 40 is used.
  • the average particle size AS of the plurality of negative electrode active material particles 31 is 100 nm or less, lithium ions can easily move inside each negative electrode active material particle 31 .
  • the energy density per unit weight of the negative electrode active material layer 30B is improved, and lithium ion migration paths (the plurality of pores 32) are easily formed inside the negative electrode active material layer 30B.
  • lithium ions move more easily inside the negative electrode active material particles 31, and the energy density per unit weight of the negative electrode active material layer 30B is further improved. Since the movement path of lithium ions is more likely to be formed inside the active material layer 30B, a higher effect can be obtained.
  • the volume density of the negative electrode active material layer 30B is 1.0 g/cm 3 to 3.5 g/cm 3 and the specific surface area of the negative electrode active material layer 30B is 1 m 2 /g to 500 m 2 /g , the energy density of the negative electrode 30 is sufficiently increased and the electrical resistance is sufficiently decreased, so that a higher effect can be obtained.
  • the electrolyte solution 40 has a pH of 11 or more, lithium ions move easily in the electrolyte solution 40 . Therefore, since the charge-discharge reaction proceeds more easily, a higher effect can be obtained.
  • the negative electrode active material layer 30B (the plurality of negative electrode active material particles 31) has the above configuration. Therefore, for the reasons described above, the lithium-ion secondary battery including the negative electrode 30 can obtain excellent operating characteristics.
  • the lithium ion secondary battery of the second embodiment is a one liquid type lithium ion secondary battery using one type of aqueous electrolyte (electrolyte 40), which is different from the lithium ion secondary battery of the first embodiment.
  • electrolyte 40 aqueous electrolyte
  • it is a two-liquid type lithium ion secondary battery using two kinds of aqueous electrolytes (a positive electrode electrolyte 61 and a negative electrode electrolyte 62).
  • FIG. 4 shows the cross-sectional structure of the lithium-ion secondary battery of the second embodiment, and corresponds to FIG.
  • the lithium-ion secondary battery of the second embodiment described here has the same configuration as the lithium-ion secondary battery of the first embodiment (FIG. 1), except for the following description. .
  • This lithium ion secondary battery as shown in FIG. 4 , the positive electrode electrolyte 61 is shaded lightly, and the negative electrode electrolyte 62 is shaded darkly.
  • the exterior body 10 has two spaces (a positive electrode chamber S1 and a negative electrode chamber S2) separated by a partition wall 50 .
  • the partition wall 50 is arranged between the positive electrode 20 and the negative electrode 30, and separates the internal space S (see FIG. 1) into the positive electrode chamber S1 and the negative electrode chamber S2. Thereby, the positive electrode 20 and the negative electrode 30 are separated from each other with the partition wall 50 interposed therebetween and face each other with the partition wall 50 interposed therebetween.
  • the partition wall 50 is a material (excluding anions) such as lithium ions (cations) intercalated and deintercalated in each of the positive electrode 20 and the negative electrode 30 without permeation of anions. pass through. This is to prevent the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 from being mixed with each other. That is, the partition wall 50 allows lithium ions to permeate from the positive electrode chamber S1 toward the negative electrode chamber S2, and allows lithium ions to permeate from the negative electrode chamber S2 toward the positive electrode chamber S1.
  • the partition wall 50 includes one or both of an ion exchange membrane and a solid electrolyte membrane.
  • the ion exchange membrane is a porous membrane (cation exchange membrane) permeable to lithium ions, and the solid electrolyte membrane has lithium ion conductivity. This is because the permeability of lithium ions in the partition walls 50 is improved.
  • the partition 50 preferably contains an ion exchange membrane rather than a solid electrolyte membrane. This is because the aqueous solvent in the positive electrode electrolyte solution 61 and the aqueous solvent in the negative electrode electrolyte solution 62 easily permeate into the partition walls 50 , so that lithium ion conductivity is improved inside the partition walls 50 .
  • the positive electrode 20 is arranged inside the positive electrode chamber S1 and absorbs and releases lithium ions
  • the negative electrode 30 is arranged inside the negative electrode chamber S2 and absorbs and releases lithium ions.
  • Each of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 is an aqueous electrolyte solution.
  • the positive electrode electrolyte 61 is housed inside the positive electrode chamber S1
  • the negative electrode electrolyte 62 is housed inside the negative electrode chamber S2. Therefore, the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 are separated from each other through the partition wall 50 so as not to be mixed with each other.
  • the positive electrode electrolyte 61 housed inside the positive electrode chamber S1 is in contact only with the positive electrode 20 without contacting the negative electrode 30 .
  • the negative electrode electrolyte 62 housed inside the negative electrode chamber S ⁇ b>2 does not contact the positive electrode 20 but contacts only the negative electrode 30 .
  • the pH of the positive electrode electrolyte 61 and the pH of the negative electrode electrolyte 62 are different from each other. Specifically, the pH of the negative electrode electrolyte 62 is higher than the pH of the positive electrode electrolyte 61 . As long as this pH relationship is satisfied, the composition of each of the positive electrode electrolyte 61 and the negative electrode electrolyte 62 (type of aqueous solvent, type and concentration of ionic substance, etc.) can be set arbitrarily.
  • composition formula (type of electrolyte salt) of the positive electrode electrolyte solution 61 and the composition formula (type of electrolyte salt) of the negative electrode electrolyte solution 62 are different from each other. This is because the above-described magnitude relationship regarding pH is easily ensured.
  • the pH value of each of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 is not particularly limited as long as the above magnitude relationship regarding pH is satisfied.
  • the pH of the negative electrode electrolyte 62 in contact with the negative electrode 30 is preferably 11 or higher, more preferably 12 or higher, and even more preferably 13 or higher. This is because the pH of the negative electrode electrolyte solution 62 becomes sufficiently high, so that the magnitude relationship regarding the pH described above is more likely to be secured. Moreover, since the difference between the pH of the positive electrode electrolyte solution 61 and the pH of the negative electrode electrolyte solution 62 becomes sufficiently large, it becomes easy to maintain the magnitude relationship between the pHs of the two.
  • the pH of the positive electrode electrolyte 61 in contact with the positive electrode 20 is preferably less than 11.
  • the pH of the positive electrode electrolyte 61 is preferably 3-8, more preferably 4-8, and even more preferably 4-6. This is because the pH of the positive electrode electrolyte solution 61 is sufficiently low, so that the above-described pH magnitude relationship is more likely to be secured and the pH magnitude relationship is easily maintained.
  • the exterior body 10 the positive electrode current collector 20A, the negative electrode current collector 30A, etc. are less likely to be corroded, the electrochemical durability (stability) of the lithium ion secondary battery is improved.
  • One or both of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 is preferably a saturated solution of an electrolyte salt (lithium salt), like the electrolyte solution 40 of the first embodiment. This is because charging/discharging reactions tend to progress stably during charging/discharging.
  • the method for confirming whether each of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 is a saturated solution of lithium salt is the same as the method for confirming whether the electrolyte solution 40 is a saturated solution of lithium salt. .
  • each of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 may be a pH buffer solution.
  • This pH buffer solution may be an aqueous solution in which a weak acid and its conjugate base are mixed, or an aqueous solution in which a weak base and its conjugate acid are mixed. This is because the pH of the positive electrode electrolyte solution and the pH of the negative electrode electrolyte solution 62 are easily maintained because the pH fluctuation is sufficiently suppressed.
  • the positive electrode electrolyte 61 contains, as an anion, any one of sulfate ion, hydrogen sulfate ion, carbonate ion, hydrogen carbonate ion, phosphate ion, monohydrogen phosphate ion, dihydrogen phosphate ion and carboxylate ion. It is preferable that one type or two or more types are included. This is because fluctuations in the pH of the positive electrode electrolyte solution 61 are sufficiently suppressed, so that the pH of the positive electrode electrolyte solution 61 can be sufficiently maintained.
  • Carboxylate ions include, for example, formate, acetate, propionate, tartrate and citrate ions.
  • the pH of the positive electrode electrolyte 61 and the negative electrode electrolyte 62 may each contain one or more of trishydroxymethylaminomethane and ethylenediaminetetraacetic acid as a buffer.
  • the positive electrode electrolyte 61 contains any one of sulfate ions, hydrogen sulfate ions, carbonate ions, hydrogen carbonate ions, phosphate ions, monohydrogen phosphate ions, and dihydrogen phosphate ions as anions.
  • the negative electrode electrolyte 62 contains hydroxide ions as anions while containing two or more kinds. This is because the pH of the positive electrode electrolyte solution 61 is easily controlled to be sufficiently high, and the pH of the negative electrode electrolyte solution 62 is easily controlled to be sufficiently low.
  • each of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 is preferably an isotonic solution having an isotonic relationship with each other. This is because the respective osmotic pressures of the positive electrode electrolyte solution 61 and the negative electrode electrolyte solution 62 are optimized, so that the pH magnitude relationship between the two can be easily maintained.
  • This lithium ion secondary battery operates as described below.
  • the lithium ions move to the negative electrode 30 via the positive electrode electrolyte 61 , the partition wall 50 and the negative electrode electrolyte 62 . .
  • the lithium ions move to the positive electrode 20 via the negative electrode electrolyte 62 , the partition wall 50 and the positive electrode electrolyte 61 , so that the positive electrode 20 absorbs the lithium ions. .
  • the pH of the negative electrode electrolyte 62 is made higher than the pH of the positive electrode electrolyte 61 by adjusting conditions such as the type and concentration (mol/kg) of the ionic substance.
  • the exterior body 10 (the positive electrode chamber S1 and the negative electrode chamber S2) to which the partition wall 50 is attached in advance is prepared.
  • the positive electrode 20 is accommodated inside the positive electrode chamber S1, and the connection terminal portion 20AT is led out from the inside of the positive electrode chamber S1 to the outside.
  • the negative electrode 30 is accommodated inside the negative electrode chamber S2, and the connection terminal portion 30AT is led out from the inside of the negative electrode chamber S2 to the outside.
  • the positive electrode electrolyte solution 61 is supplied into the positive electrode chamber S1 through a positive electrode injection hole (not shown) provided in the exterior body 10, and a negative electrode injection hole (not shown) provided in the exterior body 10 is supplied. ), the negative electrode electrolyte solution 62 is supplied into the negative electrode chamber S2. After that, each of the positive electrode injection hole and the negative electrode injection hole is sealed.
  • the positive electrode electrolyte 61 is accommodated in the positive electrode chamber S1 in which the positive electrode 20 is arranged, and the negative electrode electrolyte 62 is accommodated in the negative electrode chamber S2 in which the negative electrode 30 is arranged.
  • a two-liquid type lithium ion secondary battery using two types of aqueous electrolytes (the positive electrode electrolyte 61 and the negative electrode electrolyte 62) is completed.
  • the negative electrode active material layer 30B (the plurality of negative electrode active material particles 31) of the negative electrode 30 has the above configuration, and the pH of the negative electrode electrolyte 62 is It is higher than the pH of the liquid 61 . Therefore, excellent operating characteristics can be obtained for the same reason as the lithium ion secondary battery of the first embodiment described above.
  • the positive electrode 20 and the negative electrode 30 are separated from each other with the electrolytic solution 40 interposed therebetween.
  • the lithium ion secondary battery further includes a separator 70, so that the positive electrode 20 and the negative electrode 30 may be separated from each other with the separator 70 interposed therebetween.
  • the configuration of the lithium ion secondary battery shown in FIG. 5 is the same as the configuration of the lithium ion secondary battery shown in FIG. 1, except for the following description.
  • the separator 70 is arranged between the positive electrode 20 and the negative electrode 30 and is adjacent to the positive electrode 20 and the negative electrode 30 respectively.
  • the separator 70 is an insulating porous film that allows lithium ions to pass through while separating the positive electrode 20 and the negative electrode 30 from each other.
  • a material for forming the separator 70 is not particularly limited as long as it is a porous insulating material.
  • the separator 70 is a polymer compound film.
  • This separator 70 contains one or more of polymer compounds such as polyolefin, and specific examples of the polymer compound are polyethylene and polypropylene.
  • the separator 70 is a solid electrolyte membrane.
  • This solid electrolyte membrane is a so-called inorganic particle membrane, and the inorganic particle membrane contains inorganic particles, a binder and a fibrous substance.
  • the inorganic particles are in the form of a plurality of particles and contain one or more of inorganic materials.
  • This inorganic material includes Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ru, Rh , Pd, Ag, In, Ba, Hf, Ta, W, Re, Ir, Pt, and Au.
  • the inorganic material includes one or more of oxides, sulfides, hydroxides, carbonates, sulfates, and the like.
  • the inorganic material is preferably an inorganic solid electrolyte having excellent alkali metal ion conductivity and high water resistance. This is because hydrolysis is less likely to occur inside the lithium ion secondary battery.
  • an inorganic solid electrolyte having excellent alkali metal ion conductivity has a NASICON structure, and more specifically, is represented by the general formula LiM 2 (PO 4 ) 3 . and lithium phosphate solid electrolyte.
  • M is one or more of metal elements such as Ti, Ge, Sr, Zr, Sn and Al. Among them, M preferably contains one or more metal elements selected from Ge, Zr and Ti, and Al.
  • lithium phosphate solid electrolytes having a NASICON-type structure include LATP (Li1 + xAlxTi2 -x ( PO4 ) 3 ), Li1+ xAlxGe2 -x ( PO4 ) 3 and Li 1+x Al x Zr 2-x (PO 4 ) 3 .
  • x satisfies 0 ⁇ x ⁇ 5, preferably 0.1 ⁇ x ⁇ 0.5.
  • the lithium phosphate solid electrolyte is preferably LATP. This is because hydrolysis is less likely to occur inside the lithium-ion secondary battery because excellent water resistance can be obtained.
  • the inorganic material is preferably an oxide-based solid electrolyte.
  • oxide-based solid electrolytes include amorphous LIPON (Li 2.9 PO 3.3 N 0.46 ) and LLZ (Li 7 La 3 Zr 2 O 12 ) having a garnet structure.
  • the inorganic materials are oxide-based ceramics, carbonates, sulfates, nitride-based ceramics, and the like.
  • oxide ceramics include alumina, silica, zirconia, yttria, magnesium oxide, calcium oxide, barium oxide, strontium oxide and vanadium oxide.
  • carbonates include sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, lanthanum carbonate and cerium carbonate.
  • Specific examples of sulphates include calcium sulphate, magnesium sulphate, aluminum sulphate, gypsum and barium sulphate.
  • phosphates include hydroxyapatite, zirconium phosphate and titanium phosphate.
  • nitride ceramics are silicon nitride, titanium nitride, boron nitride and the like. Among them, alumina, silica and calcium oxide are preferably in the form of glass ceramics.
  • the shape of the inorganic particles, the average particle diameter of the inorganic particles, the content of the inorganic particles in the inorganic particle film, and the like are not particularly limited and can be set arbitrarily. However, since the inorganic particles are the main component in the inorganic particle film, the content of the inorganic particles in the inorganic particle film is preferably sufficiently large. This is because the hydrophobicity of the separator 70 is improved as the separator 70 is densified.
  • the binder contains one or more of the polymer compounds.
  • This polymer compound is a compound obtained by polymerizing a hydrocarbon monomer having a predetermined functional group, and the functional group is any one of elements such as O, S, N and F, or Two or more kinds are included as constituent elements.
  • Specific examples of polymer compounds include polyvinyl formal, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, polymethyl methacrylate and polytetrafluoroethylene.
  • the molecular weight of the binder and the content of the binder in the inorganic particle film are not particularly limited and can be set arbitrarily.
  • a fibrous substance is a plurality of fibrous substances, and includes one or more of fibrous materials.
  • the fibrous material preferably contains one or more hydrophilic functional groups, and specific examples of the hydrophilic functional groups include hydroxy, sulfone and carboxyl groups. is.
  • Specific examples of fibrous materials include cellulose fibers, polysaccharides, polyvinyl alcohol, polyacrylic acid, anionic derivatives of polystyrene and cationic derivatives of polystyrene.
  • An example of an anionic derivative of polystyrene is polystyrene sulfonate, and an example of a cationic derivative of polystyrene is polystyrenetrialkylbenzylammonium.
  • the fibrous material is preferably cellulose fiber.
  • specific examples of the fibrous material may be derivatives of the series of specific examples described above, or copolymers composed of two or more of the series of specific examples.
  • the fibrous substances contain hydrophilic functional groups, so the electrolyte 40 is easily incorporated between two or more fibrous substances. This makes it easier for the separator 70 to swell when the separator 70 is impregnated with the electrolytic solution 40 .
  • the average fiber diameter of the fibrous substance and the content of the fibrous substance in the inorganic particle film are not particularly limited and can be set arbitrarily.
  • the separator 70 may be a laminate in which a polymer compound film and an inorganic particle film are laminated together.
  • the number of layers of each of the polymer compound film and the inorganic particle film is not particularly limited and can be set arbitrarily.
  • a slurry is prepared by adding an inorganic particle film, a binder, and a fibrous substance to a solvent such as an organic solvent.
  • a solvent such as an organic solvent.
  • the slurry is then poured into the mold.
  • the slurry is dried to evaporate the solvent and then the template is removed. This completes the inorganic particle film containing the inorganic particles, the binder and the fibrous substance.
  • lithium ions can move between the positive electrode 20 and the negative electrode 30 through the separator 70, so that the same effect as in the case shown in FIG. 1 can be obtained.
  • the partition wall 50 may be the solid electrolyte membrane (inorganic particle membrane) described in the first modification. The details of this inorganic particle film are as described above.
  • lithium ions can move between the positive electrode 20 and the negative electrode 30 through the partition wall 50, so that the same effect as in the case shown in FIG. 1 can be obtained.
  • an electrolytic solution 40 that is a liquid electrolyte is used.
  • electrolyte layers 81 and 82 which are gel electrolytes, may be used.
  • the configuration of the lithium ion secondary battery shown in FIG. 6 is the same as the configuration of the lithium ion secondary battery shown in FIG. 1, except for the following description.
  • the lithium ion secondary battery newly includes a separator 70 and electrolyte layers 81 and 82 .
  • This separator 70 is arranged between the positive electrode 20 and the negative electrode 30 as described above.
  • the electrolyte layer 81 is arranged between the positive electrode 20 and the separator 70 and the electrolyte layer 82 is arranged between the negative electrode 30 and the separator 70 .
  • the electrolyte layer 81 is adjacent to the positive electrode 20 and the separator 70 respectively
  • the electrolyte layer 82 is adjacent to the negative electrode 30 and the separator 70 respectively.
  • Each of the electrolyte layers 81 and 82 contains a polymer compound together with the electrolyte solution 40, and the electrolyte solution 40 is held by the polymer compound.
  • the type of polymer compound is not particularly limited, but specifically, one or more of polyvinylidene fluoride, polyethylene oxide, and the like. In FIG. 6, each of the electrolyte layers 81 and 82 is lightly shaded.
  • the separator 70 contains one or more of polymer compounds such as polyolefin, and specific examples of the polyolefin are polyethylene and polypropylene.
  • the separator 70 may be the solid electrolyte membrane (inorganic particle membrane) described in the first modification. The details of this inorganic particle film are as described above.
  • a solvent for dilution is mixed with the electrolyte 40 and the polymer compound to prepare a sol-like precursor solution, and then the precursor solution is applied to the surface of the positive electrode 20 .
  • the procedure for forming the electrolyte layer 82 is the same as the procedure for forming the electrolyte layer 81 except that the precursor solution is applied to the surface of the negative electrode 30 .
  • lithium ions can move between the positive electrode 20 and the negative electrode 30 through the electrolyte layers 81 and 82, so that the same effect as in the case shown in FIG. 1 can be obtained. In this case, leakage of the electrolytic solution can be particularly prevented.
  • the lithium ion secondary battery is newly equipped with electrolyte layers 91 and 92.
  • the electrolyte layer 91 is arranged between the positive electrode 20 and the partition wall 50
  • the electrolyte layer 92 is arranged between the negative electrode 30 and the partition wall 50 .
  • the electrolyte layer 91 is adjacent to the positive electrode 20 and the partition wall 50 respectively
  • the electrolyte layer 92 is adjacent to the negative electrode 30 and the partition wall 50 respectively.
  • the electrolyte layer 91 contains a polymer compound together with the positive electrode electrolyte solution 61, and the positive electrode electrolyte solution 61 is held by the polymer compound.
  • the electrolyte layer 92 contains a polymer compound together with the negative electrode electrolyte solution 62, and the negative electrode electrolyte solution 62 is held by the polymer compound. Details regarding the types of polymer compounds are as described above. In FIG. 7, the electrolyte layer 91 containing the positive electrode electrolyte 61 is shaded lightly, and the electrolyte layer 92 containing the negative electrode electrolyte 62 is shaded darkly.
  • the positive electrode electrolyte 61 and the polymer compound are mixed together with a solvent for dilution to prepare a sol-like precursor solution, and then the precursor solution is applied to the surface of the positive electrode 20 .
  • the negative electrode electrolyte 62 and the polymer compound are mixed together with a solvent for dilution to prepare a sol-like precursor solution, and then the precursor solution is applied to the surface of the negative electrode 30 . .
  • the partition wall 50 may be the solid electrolyte membrane (inorganic particle membrane) described in the first modification.
  • the details of this inorganic particle film are as described above.
  • lithium ions can move between the positive electrode 20 and the negative electrode 30 via the electrolyte layers 91 and 92, so that the same effect as in the case shown in FIG. 4 can be obtained. In this case, leakage of the electrolytic solution can be particularly prevented.
  • a lithium-ion secondary battery used as a power source may be a main power source for electronic devices and electric vehicles, or may be an auxiliary power source.
  • a main power source is a power source that is preferentially used regardless of the presence or absence of other power sources.
  • An auxiliary power supply is a power supply that is used in place of the main power supply or that is switched from the main power supply.
  • lithium-ion secondary battery applications are as follows. Electronic devices such as video cameras, digital still cameras, mobile phones, laptop computers, headphone stereos, portable radios and portable information terminals. Backup power and storage devices such as memory cards. Power tools such as power drills and power saws. It is a battery pack mounted on an electronic device. Medical electronic devices such as pacemakers and hearing aids. It is an electric vehicle such as an electric vehicle (including a hybrid vehicle). It is a power storage system such as a home or industrial battery system that stores power in preparation for emergencies. In these uses, one lithium ion secondary battery may be used, or a plurality of lithium ion secondary batteries may be used.
  • the battery pack may use a single cell or an assembled battery.
  • An electric vehicle is a vehicle that operates (runs) using a lithium-ion secondary battery as a drive power source, and may be a hybrid vehicle that also includes a drive source other than the lithium-ion secondary battery.
  • household electric power storage system household electric appliances and the like can be used by using electric power stored in a lithium-ion secondary battery, which is a power storage source.
  • the application of the lithium-ion secondary battery may be other than the series of applications exemplified here.
  • a negative electrode active material a plurality of negative electrode active material particles 31 containing anatase-type titanium oxide (TiO 2 )
  • 10 parts by mass of a negative electrode binder polyethylene glycol
  • an additive Nacalai Tesque Co., Ltd.
  • a granulated powder was obtained by mixing together 1 part by weight of the company's surfactant Triton X®).
  • Table 1 shows the average particle size AS (nm) of the plurality of negative electrode active material particles 31 .
  • the plurality of negative electrode active material particles 31 were directly bonded to each other, negative electrode active material layers 30B, which are sintered compacts of the plurality of negative electrode active material particles 31, were formed on both surfaces of the negative electrode current collector 30A. .
  • the negative electrode 30 was produced.
  • Table 1 shows the volume density (g/cm 3 ) and specific surface area (m 2 /g) of the negative electrode active material layer 30B. However, regarding the specific surface area, some of the negative electrode active material layers 30B (Examples 1, 2, 5 to 7 and Comparative Examples 1 to 4) out of the series of negative electrode active material layers 30B Only the specific surface area for example 1) is shown. When the negative electrode 30 was produced, the volume density of the negative electrode active material layer 30B was adjusted by changing the press pressure described above.
  • a negative electrode 30 was produced by the same procedure except that rutile-type titanium oxide was used instead of anatase-type titanium oxide.
  • a negative electrode 30 was produced in the same manner, except that lithium titanium composite oxide (Li 4 Ti 5 O 12 (LTO)) was used instead of the anatase type titanium oxide.
  • Li 4 Ti 5 O 12 Li 4 Ti 5 O 12
  • electrolytic solution 40 (Preparation of electrolytic solution) After an ionic substance (electrolyte salt) was added to a solvent (water, which is an aqueous solvent), the solvent was stirred to prepare an electrolytic solution 40, which is an aqueous electrolytic solution.
  • the type of electrolyte salt, the concentration (mol/kg) of the electrolyte solution 40, and the pH of the electrolyte solution 40 are as shown in Table 1.
  • the electrolyte salt lithium hydroxide (LiOH), lithium carbonate (Li 2 CO 3 ), and a mixture of lithium hydroxide and potassium hydroxide (KOH) were used.
  • solvents ethylene carbonate (EC) and dimethyl carbonate (DMC) as non-aqueous solvents (organic solvents)
  • EC ethylene carbonate
  • DMC dimethyl carbonate
  • an ionic substance lithium hexafluorophosphate (LiPF 6 ) as an electrolyte salt
  • LiPF 6 lithium hexafluorophosphate
  • each of the positive electrode 20 and the negative electrode 30 was housed in the internal space S of the exterior body 10 (glass beaker) made of glass.
  • a nickel metal foil was used as the positive electrode 20 .
  • the connection terminal portions 20AT and 30AT are led out from the inside of the exterior body 10 to the outside.
  • a reference electrode silica/silver chloride electrode, not shown
  • the electrolyte solution 40 was supplied to the internal space S. As a result, the electrolytic solution 40 was accommodated in the internal space S, and the electrochemical measurement cell was completed.
  • This discharge capacity is the discharge capacity (mAh) per weight (g) of the negative electrode active material (the plurality of negative electrode active material particles 31).
  • the average particle size AS was 100 nm or less, the tendency described below was obtained.
  • the discharge capacity was further increased.
  • Sufficient discharge capacity was obtained when the volume density of the negative electrode active material layer 30B was 1.0 g/cm 3 to 3.5 g/cm 3 .
  • a two-liquid type lithium ion secondary battery (FIG. 4) described in the second embodiment was produced by the procedure described below.
  • a positive electrode active material LiFePO 4 which is a lithium phosphate compound
  • 3 parts by mass of a positive electrode binder polyvinylidene fluoride
  • 6 parts by mass of a positive electrode conductive agent graphite
  • a positive electrode mixture was obtained.
  • the positive electrode mixture was added to a solvent (N-methyl-2-pyrrolidone, which is an organic solvent), and the solvent was stirred to prepare a pasty positive electrode mixture slurry.
  • a solvent N-methyl-2-pyrrolidone, which is an organic solvent
  • a negative electrode 30 was produced according to the procedure described above.
  • Table 2 two types of negative electrodes 30 (Examples 7 and 10) using anatase-type titanium oxide as a material for forming a plurality of negative electrode active material particles 31 and a plurality of negative electrode active material particles
  • a negative electrode 30 (Comparative Example 3) using a lithium-titanium composite oxide as a material for forming the negative electrode 31 was produced.
  • the electrolytic solution 40 described above was used as the negative electrode electrolytic solution 62 .
  • the concentration (mol/kg) and pH of the negative electrode electrolyte 62 are as shown in Table 2.
  • a glass container in which a partition wall 50 (cation exchange membrane Nafion 115 (registered trademark) manufactured by Sigma-Aldrich Japan LLC) was attached was prepared. Inside the exterior body 10 , the positive electrode chamber S ⁇ b>1 and the negative electrode chamber S ⁇ b>2 are separated from each other via the partition wall 50 in advance. Subsequently, after the positive electrode 20 was accommodated inside the positive electrode chamber S1, the negative electrode 30 was accommodated inside the negative electrode chamber S2. In this case, the connection terminal portions 20AT and 30AT are led out from the inside of the exterior body 10 to the outside.
  • the cathode electrolyte solution 61 was supplied to the interior of the cathode chamber S1, and the anode electrolyte solution 62 was supplied to the interior of the anode chamber S2.
  • the positive electrode electrolyte 61 was accommodated in the positive electrode chamber S1 and the negative electrode electrolyte 62 was accommodated in the negative electrode chamber S2, thereby completing a two-liquid type lithium ion secondary battery.
  • the lithium-titanium composite oxide was used as the material for forming the plurality of negative electrode active material particles 31, constant current charging was performed at a current of 2C until the voltage reached 2.0V during charging. 2C is a current value that can discharge the battery capacity in 0.5 hours.
  • the discharge capacity was measured by discharging the lithium-ion secondary battery in the same environment. During discharge, constant current discharge was performed at a current of 2 C until the voltage reached 1.2 V, regardless of the type of material forming the plurality of negative electrode active material particles 31 .
  • initial charge/discharge efficiency (discharge capacity/charge capacity) x 100.
  • the negative electrode 30 including two types of aqueous electrolytes (a positive electrode electrolyte 61 and a negative electrode electrolyte 62) and a negative electrode active material layer 30B (a sintered body of a plurality of negative electrode active material particles 31) , the charge/discharge efficiency and the capacity retention rate varied depending on the configuration of the negative electrode 30 .
  • the negative electrode active material layer 30B of the negative electrode 30 contains a plurality of negative electrode active material particles 31, and the negative electrode active material layer 30B has a plurality of negative electrode active material particles 31 directly contacting each other.
  • Each of the plurality of negative electrode active material particles 31 contains anatase-type titanium oxide, and the average particle diameter AS of the plurality of negative electrode active material particles 31 is 100 nm or less.
  • the configuration of the lithium-ion secondary battery of the present technology has been described above while citing one embodiment and examples.
  • the configuration of the lithium-ion secondary battery of the present technology is not limited to the configuration described in one embodiment and example, and can be variously modified.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)
PCT/JP2022/029504 2021-08-02 2022-08-01 リチウムイオン二次電池用負極およびリチウムイオン二次電池 Ceased WO2023013585A1 (ja)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2023540333A JP7718490B2 (ja) 2021-08-02 2022-08-01 リチウムイオン二次電池用負極およびリチウムイオン二次電池
CN202280053937.8A CN117795732A (zh) 2021-08-02 2022-08-01 锂离子二次电池用负极以及锂离子二次电池
US18/425,790 US20240170682A1 (en) 2021-08-02 2024-01-29 Negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-126557 2021-08-02
JP2021126557 2021-08-02

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/425,790 Continuation US20240170682A1 (en) 2021-08-02 2024-01-29 Negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery

Publications (1)

Publication Number Publication Date
WO2023013585A1 true WO2023013585A1 (ja) 2023-02-09

Family

ID=85154771

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/029504 Ceased WO2023013585A1 (ja) 2021-08-02 2022-08-01 リチウムイオン二次電池用負極およびリチウムイオン二次電池

Country Status (4)

Country Link
US (1) US20240170682A1 (https=)
JP (1) JP7718490B2 (https=)
CN (1) CN117795732A (https=)
WO (1) WO2023013585A1 (https=)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024166565A1 (ja) * 2023-02-10 2024-08-15 株式会社村田製作所 抽出装置、抽出方法および水酸化リチウムの製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008114667A1 (ja) * 2007-03-16 2008-09-25 Ishihara Sangyo Kaisha, Ltd. 電極活物質及びそれを用いてなるリチウム電池
JP2013211112A (ja) * 2012-03-30 2013-10-10 Toyota Industries Corp 蓄電デバイス用負極活物質及びその製造方法、蓄電デバイス並びに車両
WO2020218456A1 (ja) * 2019-04-24 2020-10-29 株式会社村田製作所 二次電池

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6704822B2 (ja) * 2016-09-16 2020-06-03 株式会社東芝 二次電池、電池パック及び車両
JP6759171B2 (ja) * 2017-09-19 2020-09-23 株式会社東芝 リチウムイオン二次電池、電池パック及び車両
JP6837950B2 (ja) * 2017-09-21 2021-03-03 株式会社東芝 二次電池、電池パック、及び車両

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008114667A1 (ja) * 2007-03-16 2008-09-25 Ishihara Sangyo Kaisha, Ltd. 電極活物質及びそれを用いてなるリチウム電池
JP2013211112A (ja) * 2012-03-30 2013-10-10 Toyota Industries Corp 蓄電デバイス用負極活物質及びその製造方法、蓄電デバイス並びに車両
WO2020218456A1 (ja) * 2019-04-24 2020-10-29 株式会社村田製作所 二次電池

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024166565A1 (ja) * 2023-02-10 2024-08-15 株式会社村田製作所 抽出装置、抽出方法および水酸化リチウムの製造方法

Also Published As

Publication number Publication date
US20240170682A1 (en) 2024-05-23
JPWO2023013585A1 (https=) 2023-02-09
JP7718490B2 (ja) 2025-08-05
CN117795732A (zh) 2024-03-29

Similar Documents

Publication Publication Date Title
CN110048089B (zh) 正极活性物质和电池
JP7198736B6 (ja) リチウム二次電池用正極活物質およびこれを含むリチウム二次電池
CN108336328B (zh) 正极活性物质和电池
CN110880586B (zh) 正极活性物质和具备该正极活性物质的电池
JP2023094626A (ja) 二次電池
CN110048087B (zh) 正极活性物质和电池
KR20260005111A (ko) 리튬 이차 전지용 음극, 그 제조방법 및 이를 포함하는 리튬 이차전지
EP2752925A1 (en) Positive electrode active material for sodium batteries and method for producing same
KR101823729B1 (ko) 리튬 금속 산화물 및 이를 포함하는 리튬 이차전지용 음극 활물질, 및 이의 제조방법
EP2642555A2 (en) Positive electrode for a lithium ion secondary battery and a lithium ion secondary battery including the same
CN102947981A (zh) 锂离子二次电池
JP2013191540A (ja) 正極活物質およびその製造方法並びにこれを利用した２次電池
KR20150022090A (ko) 양극 활물질 및 이를 포함하는 리튬 이차전지와 이의 제조방법
JP2013214493A (ja) リチウムイオン２次電池用リチウムマンガン酸化物正極活物質およびそれを含むリチウムイオン２次電池
JP2020123460A (ja) プレドープ材、プレドープ材を含む正極、並びに、その正極を備えた非水電解質二次電池の製造方法、及び、金属酸化物の製造方法
JP7640271B2 (ja) 焼結材料及びその製造方法並びに固体電池の製造方法
CN110880585B (zh) 正极活性物质和具备该正极活性物质的电池
JP2026509067A (ja) 正極活物質、その製造方法、それを含む正極およびリチウム二次電池
JP7718490B2 (ja) リチウムイオン二次電池用負極およびリチウムイオン二次電池
CN117043974A (zh) 正极活性材料、电化学装置和用电装置
CN119895593A (zh) 锂离子二次电池用正极材料及其制造方法、锂离子二次电池用正极、以及锂离子二次电池
CN119948647A (zh) 锂离子二次电池用正极材料及其制造方法、锂离子二次电池用正极、以及锂离子二次电池
KR101580486B1 (ko) 젖음성이 향상된 이차전지용 음극 및 이를 포함하는 리튬 이차전지
KR20230126262A (ko) 음극 및 상기 음극을 포함하는 이차전지
KR101668929B1 (ko) 2차 전지 및 그 제조 방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22853004

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2023540333

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 202280053937.8

Country of ref document: CN

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 22853004

Country of ref document: EP

Kind code of ref document: A1