WO2014049985A1 - Negative electrode for lithium secondary batteries, and lithium secondary battery - Google Patents

Negative electrode for lithium secondary batteries, and lithium secondary battery Download PDF

Info

Publication number
WO2014049985A1
WO2014049985A1 PCT/JP2013/005320 JP2013005320W WO2014049985A1 WO 2014049985 A1 WO2014049985 A1 WO 2014049985A1 JP 2013005320 W JP2013005320 W JP 2013005320W WO 2014049985 A1 WO2014049985 A1 WO 2014049985A1
Authority
WO
WIPO (PCT)
Prior art keywords
active material
negative electrode
mixture layer
lithium secondary
material particles
Prior art date
Application number
PCT/JP2013/005320
Other languages
French (fr)
Japanese (ja)
Inventor
勝一郎 澤
泰三 砂野
Original Assignee
三洋電機株式会社
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 三洋電機株式会社 filed Critical 三洋電機株式会社
Publication of WO2014049985A1 publication Critical patent/WO2014049985A1/en

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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a negative electrode for a lithium secondary battery and a lithium secondary battery.
  • Patent Document 1 proposes a negative electrode in which the ratio of the binder in the vicinity of the negative electrode current collector is 2.5 times or more than the ratio of the binder in a position away from the negative electrode current collector in order to improve adhesion.
  • Patent Document 2 the silicon oxide used represented by SiO x as an active material, a high oxygen concentration SiO x arranged in the current collector side, by arranging the low SiO x oxygen concentration thereon, collector It is disclosed that body deformation is suppressed and defects due to short circuits are reduced.
  • An object of the present invention is to provide a negative electrode for a lithium secondary battery having high initial charge / discharge efficiency and excellent cycle characteristics, and a lithium secondary battery using the same.
  • the negative electrode for a lithium secondary battery of the present invention is provided on a current collector, a first mixture layer provided on the current collector, the first active material particles and the first binder, and the current collector. And a second mixture layer containing second active material particles and a second binder, and the second mixture layer is provided closer to the current collector than the first mixture layer.
  • the second active material particles are characterized in that the expansion coefficient during charging is smaller than that of the first active material particles.
  • the lithium secondary battery of the present invention is characterized by comprising a positive electrode, the negative electrode of the present invention, and a nonaqueous electrolyte.
  • a lithium secondary battery having high initial charge / discharge efficiency and excellent cycle characteristics can be obtained.
  • FIG. 5 is a cross-sectional view taken along line AA shown in FIG.
  • the first mixture layer and the second mixture layer are provided on the current collector, and the second mixture layer is formed on the current collector from the first mixture layer.
  • the expansion coefficient at the time of charging of the second active material particles included in the second mixture layer is provided on the near side. Is smaller than the expansion coefficient.
  • the stress generated by the expansion / contraction during charge / discharge increases as the distance from the current collector interface increases.
  • the 2nd mixture layer containing the 2nd active material particle with a small expansion coefficient at the time of charge is provided in the side near a collector.
  • the stress by the expansion / contraction of the active material particles at the time of charging / discharging can be relieved, and the mixture layer can be prevented from peeling from the current collector by this stress. Accordingly, the cycle characteristics of the lithium secondary battery can be improved.
  • an active material having a large expansion coefficient during charging can be used as the first active material particles. For this reason, compared with the case where only the 2nd active material particle is used as an active material, initial stage charge / discharge efficiency can be made high.
  • the first active material particles are preferably formed from Si or a Si alloy.
  • Si alloys include solid solutions of silicon and one or more other elements, intermetallic compounds of silicon and one or more other elements, and eutectic alloys of silicon and one or more other elements. It is done.
  • the method for producing the alloy include an arc melting method, a liquid quenching method, a mechanical alloying method, a sputtering method, a chemical vapor deposition method, and a firing method.
  • examples of the liquid quenching method include a single roll quenching method, a twin roll quenching method, and various atomizing methods such as a gas atomizing method, a water atomizing method, and a disk atomizing method.
  • the second active material particles those containing Si and O are preferable.
  • the surface of the SiO x particles is preferably coated with amorphous carbon.
  • SiO x has a high electronic resistance, and therefore the load characteristics are lowered. Electron conductivity can be imparted by coating the surface with amorphous carbon.
  • carbon has a large specific surface area compared to SiO x, it is easy to hold the binder. For this reason, by using SiO x particles coated with amorphous carbon as the second active material particles of the second mixture layer provided on the side close to the current collector, it is close to the interface with the current collector. More binder can be placed on the side. For this reason, the adhesiveness of a 2nd mixture layer and a collector can further be improved, and it suppresses that a 1st mixture layer and a 2nd mixture layer peel from a collector. be able to.
  • the thickness of the second mixture layer is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less.
  • the thickness of the second mixture layer is preferably 2 ⁇ m or more.
  • a second active material particles, the use of SiO x, SiO x is amount of expansion during charging is small, the charge and discharge capacity is small, often irreversible capacity at the initial charge and discharge. For this reason, when the thickness of the second mixture layer is too thick, the battery capacity may be reduced. If the thickness of the second mixture layer is too thin, the cycle characteristics may not be sufficiently improved.
  • the thickness of the first mixture layer is preferably thicker than the second mixture layer in order to increase the energy density of the electrode. Therefore, it is preferably 10 ⁇ m or more, and preferably 30 ⁇ m or less.
  • the average particle diameter D 50 (median diameter) of the second active material particles is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less. If the average particle diameter of the second active material particles becomes too large, the thickness of the second mixture layer will increase.
  • the lower limit of the average particle diameter of the second active material particles is generally 2 ⁇ m.
  • the average particle diameter D 50 (median diameter) of the first active material particles is preferably 20 ⁇ m or less, and more preferably 15 ⁇ m or less. If the average particle diameter of the first active material particles becomes too large, it becomes difficult to produce an electrode.
  • the lower limit of the average particle diameter of the first active material particles is generally 6 ⁇ m.
  • Polyimide is preferably used as the first binder and the second binder. Since polyimide has a high elastic modulus, the particles do not come out of contact even when expanded or contracted by charge / discharge. Accordingly, the active material particles can move flexibly at the contact point of the binder, and even if the active material particles expand, the active material particles can move so as to be buried in the voids. Therefore, the first mixture layer and the second mixture layer can be moved. In the agent layer, it is possible to suppress a decrease in contact points between the active material particles.
  • the polyimide it is preferable to use a polyimide obtained by heat-treating polyamic acid. By this heat treatment, the polyamic acid undergoes dehydration condensation to produce polyimide.
  • the imidization ratio of polyimide is preferably 80% or more. If the imidization ratio of the polyimide is less than 80%, the adhesion between the active material particles and the current collector may not be sufficient.
  • the imidation ratio is a mol% of the produced polyimide with respect to a polyimide precursor such as polyamic acid.
  • An imidation ratio of 80% or more can be obtained, for example, by heat-treating a polyamic acid N-methyl-pyrrolidone (NMP) solution at a temperature of 100 ° C. to 400 ° C. for 1 hour or more.
  • NMP polyamic acid N-methyl-pyrrolidone
  • the imidization rate is 80% when the heat treatment time is about 1 hour, and the imidization rate is 100% after about 3 hours.
  • the first mixture layer can be formed by applying the first mixture layer slurry containing the first active material particles and the first binder and then drying.
  • the second mixture layer can be formed by applying the second mixture layer slurry containing the second active material particles and the second binder and then drying the slurry.
  • the second mixture layer and the first mixture layer are formed, it is preferable to sinter in a non-oxidizing atmosphere. This sintering is preferably performed after the second mixture layer is formed and after the first mixture layer is formed. Moreover, after forming the second mixture layer, the first mixture layer may be formed on the first mixture layer without sintering, and then sintering may be performed.
  • Sintering is preferably performed, for example, under vacuum or in an inert atmosphere such as a nitrogen atmosphere or argon.
  • the firing temperature is preferably in the range of 200 to 500 ° C, more preferably in the range of 300 to 450 ° C.
  • a discharge plasma sintering method or a hot press method may be used.
  • the content ratio of the first active material particles and the second active material particles is in the range of 50:50 to 90:10 in terms of the mass ratio of the first active material particles to the second active material particles. Preferably, it is preferable to be within the range of 60:40 to 80:20. If the content of the second active material particles is too small, the effect of improving the adhesion with the current collector is small. When there is too much content of the 2nd active material particle, an energy density will fall as an electrode.
  • the amount of the first binder and the second binder depends on the amount and type of the first active material particles and the second active material particles used in the first mixture layer and the second mixture layer. It can be appropriately adjusted and used.
  • the expansion rate at the time of charging of the first active material particles and the second active material particles is such that electrodes using the respective active material particles are prepared, and the mixture layer is formed from the charged electrode and the discharged electrode, respectively. It can calculate by peeling and calculating
  • Expansion rate of active material particles [(volume of the mixture layer measured by peeling the mixture layer from the charged electrode) / (mixture measured by peeling the mixture layer from the discharged electrode) Layer volume)] ⁇ 100
  • the lithium secondary battery of the present invention includes a positive electrode, the negative electrode of the present invention, and a nonaqueous electrolyte.
  • the positive electrode and the non-aqueous electrolyte are not particularly limited as long as they can be used as the positive electrode and the non-aqueous electrolyte of the lithium secondary battery.
  • the positive electrode active material for example, lithium transition metal oxides such as lithium cobaltate, lithium manganate, and lithium nickelate can be used.
  • electrolyte salt of the non-aqueous electrolyte examples include LiClO 4 , LiBF 4 , LiPF 6 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiB 10 Cl 10 , lower aliphatic carboxylic acid Lithium, LiCl, LiBr, LiI, chloroborane lithium, borates, imide salts, and the like can be used.
  • LiPF 6 is preferably used from the viewpoints of ion conductivity and electrochemical stability.
  • One electrolyte salt may be used alone, or two or more electrolyte salts may be used in combination. These electrolyte salts are preferably contained in a proportion of 0.8 to 1.5 mol with respect to 1 L of the nonaqueous electrolyte.
  • non-aqueous electrolyte solvent for example, a cyclic carbonate, a chain carbonate, a cyclic carboxylic acid ester or the like is used.
  • cyclic carbonate examples include propylene carbonate (PC) and ethylene carbonate (EC).
  • chain carbonate examples include diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC).
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • DMC dimethyl carbonate
  • examples of the cyclic carboxylic acid ester include ⁇ -butyrolactone (GBL) and ⁇ -valerolactone (GVL).
  • a non-aqueous solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
  • Example 1 (Preparation of the second mixture layer) SiO which was surface-coated with amorphous carbon as negative electrode active material particles, graphite powder as negative electrode conductive agent particles, and a binder precursor solution were mixed to prepare a second mixture slurry.
  • the average particle diameter of SiO was 5 ⁇ m.
  • the average particle size of the graphite powder was 3 ⁇ m.
  • the BET specific surface area of the graphite powder was 12.5 m 2 / g.
  • the mass ratio of the negative electrode active material particles, the negative electrode conductive agent particles, and the negative electrode binder (after drying the negative electrode binder precursor solution to remove NMP, causing a polymerization reaction and an imidization reaction) is 89.53: 3.73. : 6.74.
  • a copper alloy foil (C702) having both surfaces roughened with electrolytic copper and a thickness of 18 ⁇ m.
  • the surface roughness Ra (JIS B 0601-1994) of each surface of the copper alloy foil was 0.25 ⁇ m.
  • the average peak spacing S (JIS B 0601-1994) on each surface of the copper alloy foil was 0.85 ⁇ m.
  • the second mixture slurry was applied on the current collector, and the second mixture layer was placed on the current collector.
  • the negative electrode was produced by heat-processing for 10 hours at 400 degreeC in argon atmosphere.
  • Each mixture layer mass on one side was 5.5 mg / 10 cm 2 , and the thickness was 3.7 ⁇ m.
  • the first mixture slurry is applied onto the second mixture layer of the electrode in which the second mixture layer is disposed on the current collector, and the first mixture layer is applied to the second mixture layer. Placed on top.
  • the negative electrode was produced by heat-processing for 10 hours at 400 degreeC in argon atmosphere.
  • the mixture layer mass was 16.4 mg / 10 cm 2 and the thickness was 11 ⁇ m.
  • the length of the electrode was 380 mm.
  • the electrode width was 50 mm.
  • the portion where the active material layer was formed on both sides was 21.9 mg / 10 cm 2 .
  • the total thickness of the active material layer was 29.4 ⁇ m at the portion where the active material layer was formed on both sides.
  • a nickel plate was connected to the end of the negative electrode as a negative electrode current collecting tab.
  • FIG. 1 is a schematic cross-sectional view showing the electrode structure of the negative electrode 10 of Example 1.
  • the second mixture layers 12a and 12b are provided on the opposing surfaces of the current collector 11, respectively, and the first mixture layers 12a and 12b are provided on the first mixture layers 12a and 12b, respectively.
  • Agent layers 13a and 13b are respectively provided.
  • the first mixture layers 13a and 13b each have a mass of 16.4 mg / 10 cm 2 and a thickness of 11 ⁇ m.
  • Each of the second mixture layers 12a and 12b has a mass of 5.5 mg / 10 cm 2 and a thickness of 3.7 ⁇ m.
  • Li 2 CO 3 and CoCO 3 were mixed in a mortar so that the molar ratio of Li and Co was 1: 1. Thereafter, the mixture was heat-treated in an air atmosphere at 800 ° C. for 24 hours. Then, this was pulverized to obtain a lithium cobalt composite oxide powder represented by LiCoO 2 .
  • the average particle size of the lithium cobalt composite oxide powder was 10 ⁇ m.
  • the BET specific surface area of the obtained lithium cobalt composite oxide powder (positive electrode active material powder) was 0.37 m 2 / g.
  • LiCoO 2 powder as a positive electrode active material powder, carbon material powder as positive electrode conductive material particles, and polyvinylidene fluoride as a positive electrode binder are added to NMP as a dispersion medium, and then kneaded to obtain a positive electrode mixture slurry. Obtained.
  • the mass ratio of LiCoO 2 powder, carbon material powder, and polyvinylidene fluoride was 95: 2.5: 2.5.
  • the positive electrode mixture slurry was applied on both surfaces of an aluminum foil as a positive electrode current collector, dried, and then rolled to produce a positive electrode.
  • the thickness of the aluminum foil was 15 ⁇ m.
  • the length of the aluminum foil was 402 mm.
  • the width of the aluminum foil was 50 mm.
  • the length of the coating part on the one main surface side of the aluminum foil was 340 mm.
  • variety of the application part of the one main surface side of aluminum foil was 50 mm.
  • the length of the application part on the other main surface side of the aluminum foil was 270 mm.
  • the width of the application part on the other main surface side of the aluminum foil was 50 mm.
  • the amount of the active material layer on the aluminum foil was 48 mg / cm 2 at the portion where the active material layer was formed on both surfaces.
  • the total thickness of the active material layer was 143 ⁇ m at the portion where the active material layer was formed on both sides.
  • An aluminum plate was connected to the uncoated portion of the positive electrode active material layer at the end of the positive electrode as a positive electrode current collecting tab.
  • the positive electrode and the negative electrode were opposed to each other with a separator having a thickness of 20 ⁇ m, and the positive electrode tab and the negative electrode tab were wound in a spiral shape using a cylindrical core so that both of the positive electrode tab and the negative electrode tab were on the outermost periphery. Thereafter, the winding core was pulled out to produce a spiral electrode body. Next, the spiral electrode body was crushed to obtain a flat electrode body. A schematic perspective view of the produced flat electrode body is shown in FIG. As shown in FIG. 3, the end portions of the positive electrode current collecting tab 1 and the negative electrode current collecting tab 2 are taken out from the electrode body 3. A polyethylene microporous membrane was used as the separator.
  • the length of the polyethylene microporous membrane was 450 mm.
  • the width of the polyethylene microporous membrane was 54.5 mm.
  • the piercing strength of the polyethylene microporous membrane was 340 g.
  • the porosity of the polyethylene microporous membrane was 45%.
  • Battery A1 has an exterior body 4 made of an aluminum laminate.
  • the exterior body 4 has the closing part 5 by which the edge parts of aluminum foil were heat-sealed.
  • the battery A1 further includes a positive electrode current collector tab 1, a negative electrode current collector tab 2, and an electrode body 3 (flat electrode body) wound in a state where the separator 8 is sandwiched between the positive electrode 6 and the negative electrode 7. .
  • Expansion rate (volume measured by peeling the mixture layer from the charged electrode) / (volume measured by peeling the mixture layer from the discharged electrode)
  • the mixture layer was shaved from the electrode, and the volume of the shaved mixture layer was measured with a Shimadzu dry automatic densimeter (Acupick II 1340).
  • the expansion rate when charged to the theoretical capacity was 400% for Si and 220% for SiO.
  • Comparative Example 1 A negative electrode in which only the second mixture layer was provided on the current collector using only SiO as the negative electrode active material was produced. Comparative battery B1 was produced in the same manner as in Example 1 except that this negative electrode was used. In addition, the mass of the 2nd mixture layer at this time was 36.9 mg / 10cm ⁇ 2 >, and thickness was 24.6 micrometers.
  • the capacity of the negative electrode in Comparative Example 1 is adjusted to be the same as the capacity of the negative electrode in Example 1 above.
  • Comparative Example 2 As the active material, a mixed powder in which SiO and Si were mixed at a mass ratio (SiO: Si) of 25:75 was used, and only one active material layer was formed on the current collector. A comparative battery B2 was produced in the same manner as in Example 1 except for this. The mass of the mixture layer in the electrode of Comparative Example 2 was 21.3 mg / 10 cm 2 , and the thickness was 14.2 ⁇ m.
  • Comparative Example 3 A negative electrode was produced in the same manner as in Example 1 except that only Si as the active material was used and only the first mixture layer was provided on the current collector. A comparative battery B3 was fabricated using this negative electrode. Produced.
  • the mixture layer of the electrode of Comparative Example 3 had a mass of 18.7 mg / 10 cm 2 and a thickness of 12.5 ⁇ m.
  • FIG. 2 The scanning electron microscope (SEM) photograph of the cross section of the negative electrode of battery A1 and comparative battery B2 according to this invention is shown in FIG. 2, respectively.
  • SEM scanning electron microscope
  • Constant current charging was performed until the battery voltage reached 4.2 V at a current of 1000 mA. Furthermore, constant voltage charging was performed at a voltage of 4.2 V until the current value reached 50 mA.
  • the cycle life was obtained by the following calculation method.
  • Cycle life The number of cycles when the capacity maintenance rate reached 90%.
  • the charge / discharge efficiency at the first cycle is shown in Table 1 as the initial charge / discharge efficiency.
  • the cycle life is also shown in Table 1.
  • the battery A1 according to the present invention is excellent in initial charge / discharge efficiency and cycle life. It can be seen that Comparative Battery B1 using only SiO as the negative electrode active material has a high cycle life but low initial charge / discharge efficiency. It can also be seen that the comparative battery B3 using only Si as the negative electrode active material has a cycle life inferior to that of the battery A1. In addition, it can be seen that the cycle life of the comparative battery B2 in which SiO and Si are mixed and used as the negative electrode active material is inferior to that of the battery A1.

Abstract

The present invention addresses the problem of obtaining a lithium secondary battery which has high initial charge/discharge efficiency and excellent cycle characteristics. Provided is a lithium secondary battery which is provided with: a collector; a first mixture layer that is provided on the collector and contains first active material particles and a first binder; and a second mixture layer that is provided on the collector and contains second active material particles and a second binder. The second mixture layer is arranged closer to the collector than the first mixture layer, and the expansion ratio of the second active material particles during charging is smaller than that of the first active material particles.

Description

リチウム二次電池用負極及びリチウム二次電池Negative electrode for lithium secondary battery and lithium secondary battery
　本発明は、リチウム二次電池用負極及びリチウム二次電池に関するものである。 The present invention relates to a negative electrode for a lithium secondary battery and a lithium secondary battery.
　リチウム二次電池の負極活物質として、ケイ素を含む材料を用いることが検討されている。ケイ素を含む材料を活物質として用いた場合、リチウムの吸蔵・放出の際に、活物質の体積が膨張・収縮することにより、活物質の微粉化や、活物質の集電体からの剥離を生じる。このため、電極内の集電性が低下し、充放電サイクル特性が悪くなるという問題がある。 It has been studied to use a material containing silicon as a negative electrode active material of a lithium secondary battery. When a material containing silicon is used as the active material, the volume of the active material expands and contracts during the insertion and extraction of lithium, so that the active material is pulverized and the active material is separated from the current collector. Arise. For this reason, there exists a problem that the current collection property in an electrode falls and charging / discharging cycling characteristics worsen.
　特許文献１では、密着性を向上させるため、負極集電体近傍におけるバインダーの割合が、負極集電体から離れた位置におけるバインダーの割合の２．５倍以上となる負極が提案されている。 Patent Document 1 proposes a negative electrode in which the ratio of the binder in the vicinity of the negative electrode current collector is 2.5 times or more than the ratio of the binder in a position away from the negative electrode current collector in order to improve adhesion.
　特許文献２では、活物質としてＳｉＯxで示されるケイ素酸化物を用い、集電体側に酸素濃度の高いＳｉＯxを配置し、その上に酸素濃度の低いＳｉＯxを配置することにより、集電体の変形を抑制し、短絡による不良を低下させることが開示されている。 In Patent Document 2, the silicon oxide used represented by SiO x as an active material, a high oxygen concentration SiO x arranged in the current collector side, by arranging the low SiO x oxygen concentration thereon, collector It is disclosed that body deformation is suppressed and defects due to short circuits are reduced.
特開２００７－２００６８６号公報JP 2007-200766 A 特開２００６－１０７９１２号公報JP 2006-107912 A
　しかしながら、特許文献１及び特許文献２に開示された技術では、合剤層と集電体との密着性が不十分であるため、膨張収縮により集電性が低下し、サイクル特性が低下するという問題があった。 However, in the techniques disclosed in Patent Document 1 and Patent Document 2, since the adhesion between the mixture layer and the current collector is insufficient, the current collection performance is reduced due to expansion and contraction, and the cycle characteristics are reduced. There was a problem.
　本発明の目的は、初期充放電効率が高く、かつサイクル特性に優れたリチウム二次電池用負極及びそれを用いたリチウム二次電池を提供することにある。 An object of the present invention is to provide a negative electrode for a lithium secondary battery having high initial charge / discharge efficiency and excellent cycle characteristics, and a lithium secondary battery using the same.
　本発明のリチウム二次電池用負極は、集電体と、集電体上に設けられ、第１の活物質粒子及び第１のバインダーを含む第１の合剤層と、集電体上に設けられ、第２の活物質粒子及び第２のバインダーを含む第２の合剤層とを備え、第２の合剤層は、第１の合剤層より集電体に近い側に設けられており、第２の活物質粒子の充電時における膨張率が、第１の活物質粒子よりも小さいことを特徴している。 The negative electrode for a lithium secondary battery of the present invention is provided on a current collector, a first mixture layer provided on the current collector, the first active material particles and the first binder, and the current collector. And a second mixture layer containing second active material particles and a second binder, and the second mixture layer is provided closer to the current collector than the first mixture layer. The second active material particles are characterized in that the expansion coefficient during charging is smaller than that of the first active material particles.
　本発明のリチウム二次電池は、正極と、上記本発明の負極と、非水電解質とを備えることを特徴としている。 The lithium secondary battery of the present invention is characterized by comprising a positive electrode, the negative electrode of the present invention, and a nonaqueous electrolyte.
　本発明によれば、初期充放電効率が高く、かつサイクル特性に優れたリチウム二次電池とすることができる。 According to the present invention, a lithium secondary battery having high initial charge / discharge efficiency and excellent cycle characteristics can be obtained.
本発明に従う一実施形態のリチウム二次電池用負極を示す模式的断面図である。It is typical sectional drawing which shows the negative electrode for lithium secondary batteries of one Embodiment according to this invention. 実施例の電池Ａ１及び比較例の電池Ｂ２の負極の断面を示す走査型電子顕微鏡（ＳＥＭ）写真を示す図である。It is a figure which shows the scanning electron microscope (SEM) photograph which shows the cross section of the negative electrode of battery A1 of an Example, and battery B2 of a comparative example. 実施例における電極体を示す斜視図である。It is a perspective view which shows the electrode body in an Example. 実施例におけるリチウム二次電池を示す平面図である。It is a top view which shows the lithium secondary battery in an Example. 図４に示すＡ－Ａ線に沿う断面図である。FIG. 5 is a cross-sectional view taken along line AA shown in FIG.
　本発明においては、集電体の上に、第１の合剤層及び第２の合剤層が設けられており、第２の合剤層は、第１の合剤層より集電体に近い側に設けられ、かつ第２の合剤層中に含まれる第２の活物質粒子の充電時における膨張率が、第１の合剤層中に含まれる第１の活物質粒子の充電時における膨張率よりも小さい。充放電時における膨張・収縮により生じた応力は、集電体との界面に近いほど大きくなる。本発明においては、集電体に近い側に、充電時における膨張率が小さい第２の活物質粒子を含む第２の合剤層が設けられている。このため、充放電時の活物質粒子の膨張・収縮による応力を緩和することができ、この応力によって合剤層が集電体から剥離するのを抑制することができる。従って、リチウム二次電池のサイクル特性を向上させることができる。 In the present invention, the first mixture layer and the second mixture layer are provided on the current collector, and the second mixture layer is formed on the current collector from the first mixture layer. When the first active material particles included in the first mixture layer are charged, the expansion coefficient at the time of charging of the second active material particles included in the second mixture layer is provided on the near side. Is smaller than the expansion coefficient. The stress generated by the expansion / contraction during charge / discharge increases as the distance from the current collector interface increases. In this invention, the 2nd mixture layer containing the 2nd active material particle with a small expansion coefficient at the time of charge is provided in the side near a collector. For this reason, the stress by the expansion / contraction of the active material particles at the time of charging / discharging can be relieved, and the mixture layer can be prevented from peeling from the current collector by this stress. Accordingly, the cycle characteristics of the lithium secondary battery can be improved.
　また、本発明においては、充電時における膨張率が大きな活物質を、第１の活物質粒子として用いることができる。このため、活物質として第２の活物質粒子のみを用いた場合に比べ、初期充放電効率を高くすることができる。 In the present invention, an active material having a large expansion coefficient during charging can be used as the first active material particles. For this reason, compared with the case where only the 2nd active material particle is used as an active material, initial stage charge / discharge efficiency can be made high.
　第１の活物質粒子は、ＳｉまたはＳｉ合金から形成されていることが好ましい。ＳｉまたはＳｉ合金から形成することにより、高い充放電容量を得ることができる。Ｓｉ合金としては、ケイ素と他の１種以上の元素との固溶体、ケイ素と他の１種以上の元素との金属間化合物、ケイ素と他の１種以上の元素との共晶合金などが挙げられる。合金の作製方法としては、アーク溶解法、液体急冷法、メカニカルアロイング法、スパッタリング法、化学気相成長法、焼成法などが挙げられる。特に、液体急冷法としては、単ロール急冷法、双ロール急冷法、及びガスアトマイズ法、水アトマイズ法、ディスクアトマイズ法などの各種アトマイズ法が挙げられる。 The first active material particles are preferably formed from Si or a Si alloy. By forming from Si or Si alloy, a high charge / discharge capacity can be obtained. Examples of Si alloys include solid solutions of silicon and one or more other elements, intermetallic compounds of silicon and one or more other elements, and eutectic alloys of silicon and one or more other elements. It is done. Examples of the method for producing the alloy include an arc melting method, a liquid quenching method, a mechanical alloying method, a sputtering method, a chemical vapor deposition method, and a firing method. In particular, examples of the liquid quenching method include a single roll quenching method, a twin roll quenching method, and various atomizing methods such as a gas atomizing method, a water atomizing method, and a disk atomizing method.
　第２の活物質粒子としては、ＳｉとＯを含有するものが好ましい。このようなものとして、ＳｉＯx（ｘ＝０．５～１．５）からなる粒子が挙げられる。 As the second active material particles, those containing Si and O are preferable. Examples of such a material include particles made of SiO x (x = 0.5 to 1.5).
　ＳｉＯx粒子は、その表面が、非晶質炭素で被覆されていることが好ましい。ＳｉＯxは、電子抵抗が高く、そのため負荷特性が低下する。表面を非晶質炭素で被覆することにより、電子伝導性を付与することができる。また、炭素は、ＳｉＯxと比較して、比表面積が大きいため、バインダーを保持しやすい。このため、集電体に近い側に設けられる第２の合剤層の第２の活物質粒子として、非晶質炭素で被覆したＳｉＯx粒子を用いることにより、集電体との界面に近い側に、より多くのバインダーを配置することができる。このため、第２の合剤層と集電体との密着性をさらに改善することができ、第１の合剤層及び第２の合剤層が、集電体から剥離するのを抑制することができる。 The surface of the SiO x particles is preferably coated with amorphous carbon. SiO x has a high electronic resistance, and therefore the load characteristics are lowered. Electron conductivity can be imparted by coating the surface with amorphous carbon. In addition, since carbon has a large specific surface area compared to SiO x, it is easy to hold the binder. For this reason, by using SiO x particles coated with amorphous carbon as the second active material particles of the second mixture layer provided on the side close to the current collector, it is close to the interface with the current collector. More binder can be placed on the side. For this reason, the adhesiveness of a 2nd mixture layer and a collector can further be improved, and it suppresses that a 1st mixture layer and a 2nd mixture layer peel from a collector. be able to.
　第２の合剤層の厚みは、１０μｍ以下であることが好ましく、さらに好ましくは５μｍ以下である。また、第２の合剤層の厚みは、２μｍ以上であることが好ましい。第２の活物質粒子として、ＳｉＯxを用いた場合、ＳｉＯxは、充電時における膨張量は小さいが、充放電容量が小さく、初期充放電での不可逆容量が多い。このため、第２の合剤層の厚みを厚くしすぎると、電池容量が低下する場合がある。また、第２の合剤層の厚みが薄すぎると、サイクル特性を十分に高めることができない場合がある。 The thickness of the second mixture layer is preferably 10 μm or less, more preferably 5 μm or less. The thickness of the second mixture layer is preferably 2 μm or more. A second active material particles, the use of SiO x, SiO x is amount of expansion during charging is small, the charge and discharge capacity is small, often irreversible capacity at the initial charge and discharge. For this reason, when the thickness of the second mixture layer is too thick, the battery capacity may be reduced. If the thickness of the second mixture layer is too thin, the cycle characteristics may not be sufficiently improved.
　第１の合剤層の厚みは、電極のエネルギー密度を高めるため、第２の合剤層よりも厚いことが好ましい。従って、１０μｍ以上であることが好ましく、３０μｍ以下であることが好ましい。 The thickness of the first mixture layer is preferably thicker than the second mixture layer in order to increase the energy density of the electrode. Therefore, it is preferably 10 μm or more, and preferably 30 μm or less.
　第２の活物質粒子の平均粒径Ｄ50（メディアン径）は、１０μｍ以下であることが好ましく、さらに好ましくは５μｍ以下である。第２の活物質粒子の平均粒径が大きくなりすぎると、第２の合剤層の厚みが大きくなってしまう。 The average particle diameter D 50 (median diameter) of the second active material particles is preferably 10 μm or less, more preferably 5 μm or less. If the average particle diameter of the second active material particles becomes too large, the thickness of the second mixture layer will increase.
　第２の活物質粒子の平均粒径の下限値は、一般に２μmである。 The lower limit of the average particle diameter of the second active material particles is generally 2 μm.
　第１の活物質粒子の平均粒径Ｄ50（メディアン径）は、２０μｍ以下であることが好ましく、さらに好ましくは１５μｍ以下である。第１の活物質粒子の平均粒径が大きくなりすぎると、電極の作製が困難となる。 The average particle diameter D 50 (median diameter) of the first active material particles is preferably 20 μm or less, and more preferably 15 μm or less. If the average particle diameter of the first active material particles becomes too large, it becomes difficult to produce an electrode.
　第１の活物質粒子の平均粒径の下限値は、一般に６μｍである。 The lower limit of the average particle diameter of the first active material particles is generally 6 μm.
　第１のバインダー及び第２のバインダーとしては、ポリイミドが好ましく用いられる。ポリイミドは弾性率が高いので、充放電による膨張・収縮でも粒子同士の接触が外れることがなくなる。従って、バインダーの接触点で活物質粒子がフレキシブルに動くことが可能となり、活物質粒子が膨張しても空隙に埋まるように活物質粒子が動けるので、第１の合剤層及び第２の合剤層において、活物質粒子同士の接触点が減少するのを抑制することができる。 Polyimide is preferably used as the first binder and the second binder. Since polyimide has a high elastic modulus, the particles do not come out of contact even when expanded or contracted by charge / discharge. Accordingly, the active material particles can move flexibly at the contact point of the binder, and even if the active material particles expand, the active material particles can move so as to be buried in the voids. Therefore, the first mixture layer and the second mixture layer can be moved. In the agent layer, it is possible to suppress a decrease in contact points between the active material particles.
　ポリイミドとしては、ポリアミド酸を熱処理することによって得られるポリイミドを用いることが好ましい。この熱処理によりポリアミド酸が脱水縮合して、ポリイミドが生成する。本発明においては、ポリイミドのイミド化率は、８０％以上のものが好ましい。ポリイミドのイミド化率が８０％未満であると、活物質粒子及び集電体との密着性が十分でない場合がある。ここで、イミド化率とは、ポリアミド酸などのポリイミド前駆体に対する生成したポリイミドのモル％である。イミド化率８０％以上のものは、例えば、ポリアミド酸のＮ－メチル－ピロリドン（ＮＭＰ）溶液を、１００℃～４００℃の温度で１時間以上熱処理することにより得ることができる。また、３５０℃で熱処理する場合、熱処理時間が約１時間でイミド化率は８０％となり、約３時間でイミド化率は１００％となる。 As the polyimide, it is preferable to use a polyimide obtained by heat-treating polyamic acid. By this heat treatment, the polyamic acid undergoes dehydration condensation to produce polyimide. In the present invention, the imidization ratio of polyimide is preferably 80% or more. If the imidization ratio of the polyimide is less than 80%, the adhesion between the active material particles and the current collector may not be sufficient. Here, the imidation ratio is a mol% of the produced polyimide with respect to a polyimide precursor such as polyamic acid. An imidation ratio of 80% or more can be obtained, for example, by heat-treating a polyamic acid N-methyl-pyrrolidone (NMP) solution at a temperature of 100 ° C. to 400 ° C. for 1 hour or more. When heat treatment is performed at 350 ° C., the imidization rate is 80% when the heat treatment time is about 1 hour, and the imidization rate is 100% after about 3 hours.
　第１の合剤層は、第１の活物質粒子及び第１のバインダーを含む第１の合剤層スラリーを塗布した後、乾燥することにより形成することができる。第２の合剤層も、同様に、第２の活物質粒子及び第２のバインダーを含む第２の合剤層スラリーを塗布した後、乾燥することにより形成することができる。 The first mixture layer can be formed by applying the first mixture layer slurry containing the first active material particles and the first binder and then drying. Similarly, the second mixture layer can be formed by applying the second mixture layer slurry containing the second active material particles and the second binder and then drying the slurry.
　本発明においては、第２の合剤層及び第１の合剤層を形成した後、非酸化性雰囲気下で焼結することが好ましい。この焼結は、第２の合剤層を形成した後及び第１の合剤層を形成した後それぞれ行うことが好ましい。また、第２の合剤層を形成した後、焼結せずに第１の合剤層をその上に形成し、その後焼結を行ってもよい。 In the present invention, after the second mixture layer and the first mixture layer are formed, it is preferable to sinter in a non-oxidizing atmosphere. This sintering is preferably performed after the second mixture layer is formed and after the first mixture layer is formed. Moreover, after forming the second mixture layer, the first mixture layer may be formed on the first mixture layer without sintering, and then sintering may be performed.
　焼結は、例えば、真空下、または窒素雰囲気もしくはアルゴンなどの不活性雰囲気下で行うことが好ましい。焼成温度は、好ましくは２００～５００℃の範囲内であり、さらに好ましくは３００～４５０℃の範囲内である。焼結する方法として、放電プラズマ焼結法やホットプレス法を用いてもよい。 Sintering is preferably performed, for example, under vacuum or in an inert atmosphere such as a nitrogen atmosphere or argon. The firing temperature is preferably in the range of 200 to 500 ° C, more preferably in the range of 300 to 450 ° C. As a method for sintering, a discharge plasma sintering method or a hot press method may be used.
　本発明において、第１の活物質粒子と第２の活物質粒子の含有割合は、第１の活物質粒子：第２の活物質粒子の質量比で、５０：５０～９０：１０の範囲内とすることが好ましく、さらには６０：４０～８０：２０の範囲内とすることが好ましい。第２の活物質粒子の含有量が少なすぎると、集電体との密着性改善効果は少ない。第２の活物質粒子の含有量が多すぎると、電極としてエネルギー密度が下がってしまう。 In the present invention, the content ratio of the first active material particles and the second active material particles is in the range of 50:50 to 90:10 in terms of the mass ratio of the first active material particles to the second active material particles. Preferably, it is preferable to be within the range of 60:40 to 80:20. If the content of the second active material particles is too small, the effect of improving the adhesion with the current collector is small. When there is too much content of the 2nd active material particle, an energy density will fall as an electrode.
　第１のバインダー及び第２のバインダーの量は、第１の合剤層及び第２の合剤層に用いる第１の活物質粒子及び第２の活物質粒子の量や種類などに応じて、適宜調整して用いることができる。 The amount of the first binder and the second binder depends on the amount and type of the first active material particles and the second active material particles used in the first mixture layer and the second mixture layer. It can be appropriately adjusted and used.
　第１の活物質粒子及び第２の活物質粒子の充電時における膨張率は、それぞれの活物質粒子を用いた電極を作製し、充電状態の電極及び放電状態の電極より、それぞれ合剤層を剥離して、それぞれの合剤層の体積変化を求めることにより算出することができる。具体的には、以下の式から算出することができる。 The expansion rate at the time of charging of the first active material particles and the second active material particles is such that electrodes using the respective active material particles are prepared, and the mixture layer is formed from the charged electrode and the discharged electrode, respectively. It can calculate by peeling and calculating | requiring the volume change of each mixture layer. Specifically, it can be calculated from the following equation.
　活物質粒子の膨張率（％）＝〔（充電状態の電極より合剤層を剥離して測定した合剤層の体積）／（放電状態の電極より合剤層を剥離して測定した合剤層の体積）〕×１００ Expansion rate of active material particles (%) = [(volume of the mixture layer measured by peeling the mixture layer from the charged electrode) / (mixture measured by peeling the mixture layer from the discharged electrode) Layer volume)] × 100
　本発明のリチウム二次電池は、正極と、上記本発明の負極と、非水電解質とを備えている。 The lithium secondary battery of the present invention includes a positive electrode, the negative electrode of the present invention, and a nonaqueous electrolyte.
　正極及び非水電解質としては、リチウム二次電池の正極及び非水電解質として用いることができるものであれば特に限定されるものではない。正極活物質としては、例えば、コバルト酸リチウム、マンガン酸リチウム、ニッケル酸リチウムなどのリチウム遷移金属酸化物等を用いることができる。 The positive electrode and the non-aqueous electrolyte are not particularly limited as long as they can be used as the positive electrode and the non-aqueous electrolyte of the lithium secondary battery. As the positive electrode active material, for example, lithium transition metal oxides such as lithium cobaltate, lithium manganate, and lithium nickelate can be used.
　非水電解質の電解質塩としては、例えばＬｉＣｌＯ4、ＬｉＢＦ4、ＬｉＰＦ6、ＬｉＡｌＣｌ4、ＬｉＳｂＦ6、ＬｉＳＣＮ、ＬｉＣＦ3ＳＯ3、ＬｉＣＦ3ＣＯ2、ＬｉＡｓＦ6、ＬｉＢ10Ｃｌ10、低級脂肪族カルボン酸リチウム、ＬｉＣｌ、ＬｉＢｒ、ＬｉＩ、クロロボランリチウム、ホウ酸塩類、イミド塩類などを用いることができる。この中でも、イオン伝導性と電気化学的安定性の観点から、ＬｉＰＦ6を用いることが好ましい。電解質塩は、１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。これら電解質塩は、非水電解質１Ｌに対し０．８～１．５ｍｏｌの割合で含まれていることが好ましい。 Examples of the electrolyte salt of the non-aqueous electrolyte include LiClO 4 , LiBF 4 , LiPF 6 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiB 10 Cl 10 , lower aliphatic carboxylic acid Lithium, LiCl, LiBr, LiI, chloroborane lithium, borates, imide salts, and the like can be used. Among these, LiPF 6 is preferably used from the viewpoints of ion conductivity and electrochemical stability. One electrolyte salt may be used alone, or two or more electrolyte salts may be used in combination. These electrolyte salts are preferably contained in a proportion of 0.8 to 1.5 mol with respect to 1 L of the nonaqueous electrolyte.
　非水電解質の溶媒としては、例えば、環状炭酸エステル、鎖状炭酸エステル、環状カルボン酸エステルなどが用いられる。環状炭酸エステルとしては、プロピレンカーボネート（ＰＣ）、エチレンカーボネート（ＥＣ）などが挙げられる。鎖状炭酸エステルとしては、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）、ジメチルカーボネート（ＤＭＣ）などが挙げられる。環状カルボン酸エステルとしては、γ－ブチロラクトン（ＧＢＬ）、γ－バレロラクトン（ＧＶＬ）などが挙げられる。非水溶媒は、１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。 As the non-aqueous electrolyte solvent, for example, a cyclic carbonate, a chain carbonate, a cyclic carboxylic acid ester or the like is used. Examples of the cyclic carbonate include propylene carbonate (PC) and ethylene carbonate (EC). Examples of the chain carbonate include diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC). Examples of the cyclic carboxylic acid ester include γ-butyrolactone (GBL) and γ-valerolactone (GVL). A non-aqueous solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
　以下、本発明を実施例に基づいてさらに詳細に説明するが、本発明は以下の実施例に限定されるものではなく、その要旨を変更しない範囲において適宜変更して実施することが可能なものである。 Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited to the following examples, and can be implemented with appropriate modifications within a range that does not change the gist thereof. It is.
　（実施例１）
　（第２の合剤層の作製）
　負極活物質粒子としての、非晶質炭素で表面被覆されたＳｉＯと、負極導電剤粒子としての黒鉛粉末と、バインダー前駆体溶液とを混合し、第２の合剤スラリーを調製した。ＳｉＯの平均粒径は、５μｍであった。黒鉛粉末の平均粒径は、３μｍであった。黒鉛粉末のＢＥＴ比表面積は、１２．５ｍ2／ｇであった。負極活物質粒子と負極導電剤粒子と負極バインダー（負極バインダー前駆体溶液を乾燥させてＮＭＰを除去し、重合反応及びイミド化反応させた後のもの）の質量比を８９．５３：３．７３：６．７４とした。負極集電体として、両面が電解銅で粗化されており、厚さが１８μｍである銅合金箔（Ｃ７０２
５合金箔、組成；Ｃｕ　９６．２質量％、Ｎｉ　３質量％、Ｓｉ　０．６５質量％、Ｍｇ　０．１５質量％）を用いた。銅合金箔の各面の表面粗さＲａ（ＪＩＳ　Ｂ　０６０１－１９９４）は、０．２５μｍであった。銅合金箔の各面の平均山間隔Ｓ（ＪＩＳ　Ｂ　０６０１－１９９４）は、０．８５μｍであった。 (Example 1)
(Preparation of the second mixture layer)
SiO which was surface-coated with amorphous carbon as negative electrode active material particles, graphite powder as negative electrode conductive agent particles, and a binder precursor solution were mixed to prepare a second mixture slurry. The average particle diameter of SiO was 5 μm. The average particle size of the graphite powder was 3 μm. The BET specific surface area of the graphite powder was 12.5 m 2 / g. The mass ratio of the negative electrode active material particles, the negative electrode conductive agent particles, and the negative electrode binder (after drying the negative electrode binder precursor solution to remove NMP, causing a polymerization reaction and an imidization reaction) is 89.53: 3.73. : 6.74. As a negative electrode current collector, a copper alloy foil (C702) having both surfaces roughened with electrolytic copper and a thickness of 18 μm.
5 alloy foil, composition; Cu 96.2 mass%, Ni 3 mass%, Si 0.65 mass%, Mg 0.15 mass%) were used. The surface roughness Ra (JIS B 0601-1994) of each surface of the copper alloy foil was 0.25 μm. The average peak spacing S (JIS B 0601-1994) on each surface of the copper alloy foil was 0.85 μm.
　第２の合剤スラリーを集電体上に塗布し、第２の合剤層を集電体上に配置した。 The second mixture slurry was applied on the current collector, and the second mixture layer was placed on the current collector.
　その後、アルゴン雰囲気下で４００℃、１０時間熱処理することにより負極を作製した。片面のそれぞれの合剤層質量は５．５ｍｇ／１０cｍ2、厚みは３．７μｍであった。 Then, the negative electrode was produced by heat-processing for 10 hours at 400 degreeC in argon atmosphere. Each mixture layer mass on one side was 5.5 mg / 10 cm 2 , and the thickness was 3.7 μm.
　（第１の合剤層の作製）
　負極活物質粒子としてのＳｉと、負極導電剤粒子としての黒鉛粉末と、バインダー前駆体溶液とを混合し、第１の合剤スラリーを調製した。Ｓｉ粉末の平均粒径は１０μｍであった。黒鉛粉末の平均粒径は、３μｍであった。黒鉛粉末のＢＥＴ比表面積は、１２．５ｍ2／ｇであった。負極活物質粒子と負極導電剤粒子と負極バインダー（負極バインダー前駆体溶液を乾燥させてＮＭＰを除去し、重合反応及びイミド化反応させた後のもの）の質量比を８９．５３：３．７３：６．７４とした。第１の合剤スラリーを、第２の合剤層が集電体に配置された電極の第２の合剤層の上に塗布し、第１の合剤層を第２の合剤層の上に配置した。 (Preparation of the first mixture layer)
Si as the negative electrode active material particles, graphite powder as the negative electrode conductive agent particles, and the binder precursor solution were mixed to prepare a first mixture slurry. The average particle size of the Si powder was 10 μm. The average particle size of the graphite powder was 3 μm. The BET specific surface area of the graphite powder was 12.5 m 2 / g. The mass ratio of the negative electrode active material particles, the negative electrode conductive agent particles, and the negative electrode binder (after drying the negative electrode binder precursor solution to remove NMP, causing a polymerization reaction and an imidization reaction) is 89.53: 3.73. : 6.74. The first mixture slurry is applied onto the second mixture layer of the electrode in which the second mixture layer is disposed on the current collector, and the first mixture layer is applied to the second mixture layer. Placed on top.
　その後、アルゴン雰囲気下で４００℃、１０時間熱処理することにより負極を作製した。合剤層質量は１６．４ｍｇ／１０ｃｍ2、厚みは１１μｍであった。 Then, the negative electrode was produced by heat-processing for 10 hours at 400 degreeC in argon atmosphere. The mixture layer mass was 16.4 mg / 10 cm 2 and the thickness was 11 μm.
　（負極の作製）
　上記電極の長さは、３８０ｍｍであった。電極の幅は、５０ｍｍであった。両面に活物質層が形成されている部分は２１．９ｍｇ／１０ｃｍ2であった。活物質層の総厚みは、両面に活物質層が形成されている部分で２９．４μｍであった。負極の端部に、負極集電タブとしてニッケル板を接続した。 (Preparation of negative electrode)
The length of the electrode was 380 mm. The electrode width was 50 mm. The portion where the active material layer was formed on both sides was 21.9 mg / 10 cm 2 . The total thickness of the active material layer was 29.4 μm at the portion where the active material layer was formed on both sides. A nickel plate was connected to the end of the negative electrode as a negative electrode current collecting tab.
　図１は、実施例１の負極１０の電極構造を示す模式的断面図である。図１に示すように、集電体１１の対向する表面上に第２の合剤層１２ａ及び１２ｂがそれぞれ設けられており、第２の合剤層１２ａ及び１２ｂの上に、第１の合剤層１３ａ及び１３ｂがそれぞれ設けられている。 FIG. 1 is a schematic cross-sectional view showing the electrode structure of the negative electrode 10 of Example 1. FIG. As shown in FIG. 1, the second mixture layers 12a and 12b are provided on the opposing surfaces of the current collector 11, respectively, and the first mixture layers 12a and 12b are provided on the first mixture layers 12a and 12b, respectively. Agent layers 13a and 13b are respectively provided.
　第１の合剤層１３ａ及び１３ｂは、それぞれ質量１６．４ｍｇ／１０ｃｍ2であり、厚さ１１μｍである。第２の合剤層１２ａ及び１２ｂは、それぞれ質量５．５ｍｇ／１０ｃｍ2であり、厚さ３．７μｍである。 The first mixture layers 13a and 13b each have a mass of 16.4 mg / 10 cm 2 and a thickness of 11 μm. Each of the second mixture layers 12a and 12b has a mass of 5.5 mg / 10 cm 2 and a thickness of 3.7 μm.
　〔正極の作製〕
　（リチウム遷移金属複合酸化物の作製）
　Ｌｉ2ＣＯ3とＣｏＣＯ3とを、ＬｉとＣｏとのモル比が１：１になるようにして乳鉢にて混合した。その後、混合物を８００℃の空気雰囲気中にて２４時間熱処理した。その後、これを粉砕して、ＬｉＣｏＯ2で表されるリチウムコバルト複合酸化物の粉末を得た。リチウムコバルト複合酸化物の粉末の平均粒径は、１０μｍであった。得られたリチウムコバルト複合酸化物粉末（正極活物質粉末）のＢＥＴ比表面積は、０．３７ｍ2／ｇであった。 [Production of positive electrode]
(Preparation of lithium transition metal composite oxide)
Li 2 CO 3 and CoCO 3 were mixed in a mortar so that the molar ratio of Li and Co was 1: 1. Thereafter, the mixture was heat-treated in an air atmosphere at 800 ° C. for 24 hours. Then, this was pulverized to obtain a lithium cobalt composite oxide powder represented by LiCoO 2 . The average particle size of the lithium cobalt composite oxide powder was 10 μm. The BET specific surface area of the obtained lithium cobalt composite oxide powder (positive electrode active material powder) was 0.37 m 2 / g.
　（正極の作製）
　正極活物質粉末としてのＬｉＣｏＯ2粉末と、正極導電材粒子としての炭素材料粉末と、正極バインダーとしてのポリフッ化ビニリデンとを、分散媒としてのＮＭＰに加えた後、混練し、正極合剤スラリーを得た。ＬｉＣｏＯ2粉末と炭素材料粉末とポリフッ化ビニリデンとの質量比（ＬｉＣｏＯ2粉末：炭素材料粉末：ポリフッ化ビニリデン）は、９５：２．５：２．５とした。 (Preparation of positive electrode)
LiCoO 2 powder as a positive electrode active material powder, carbon material powder as positive electrode conductive material particles, and polyvinylidene fluoride as a positive electrode binder are added to NMP as a dispersion medium, and then kneaded to obtain a positive electrode mixture slurry. Obtained. The mass ratio of LiCoO 2 powder, carbon material powder, and polyvinylidene fluoride (LiCoO 2 powder: carbon material powder: polyvinylidene fluoride) was 95: 2.5: 2.5.
　正極合剤スラリーを、正極集電体としてのアルミニウム箔の両面の上に塗布し、乾燥させた後に、圧延することにより正極を作製した。アルミニウム箔の厚みは、１５μｍであった。アルミニウム箔の長さは、４０２ｍｍであった。アルミニウム箔の幅は、５０ｍｍであった。アルミニウム箔の一主面側の塗布部の長さは、３４０ｍｍであった。アルミニウム箔の一主面側の塗布部の幅は、５０ｍｍであった。アルミニウム箔の他主面側の塗布部の長さは、２７０ｍｍであった。アルミニウム箔の他主面側の塗布部の幅は、５０ｍｍであった。アルミニウム箔上の活物質層量は、両面に活物質層が形成されている部分で４８ｍｇ／ｃｍ2であった。活物質層の総厚みは、両面に活物質層が形成されている部分で１４３μｍであった。 The positive electrode mixture slurry was applied on both surfaces of an aluminum foil as a positive electrode current collector, dried, and then rolled to produce a positive electrode. The thickness of the aluminum foil was 15 μm. The length of the aluminum foil was 402 mm. The width of the aluminum foil was 50 mm. The length of the coating part on the one main surface side of the aluminum foil was 340 mm. The width | variety of the application part of the one main surface side of aluminum foil was 50 mm. The length of the application part on the other main surface side of the aluminum foil was 270 mm. The width of the application part on the other main surface side of the aluminum foil was 50 mm. The amount of the active material layer on the aluminum foil was 48 mg / cm 2 at the portion where the active material layer was formed on both surfaces. The total thickness of the active material layer was 143 μm at the portion where the active material layer was formed on both sides.
　正極の端部にある正極活物質層の未塗布部分に、正極集電タブとしてアルミニウム板を接続した。 An aluminum plate was connected to the uncoated portion of the positive electrode active material layer at the end of the positive electrode as a positive electrode current collecting tab.
　〔非水電解液の作製〕
　アルゴン雰囲気下で、フルオロエチレンカーボネート（ＦＥＣ）とメチルエチルカーボネート（ＭＥＣ）とを混合した。フルオロエチレンカーボネート（ＦＥＣ）とメチルエチルカーボネート（ＭＥＣ）との体積比（ＦＥＣ：ＭＥＣ）は、２：８とした。得られた混合溶媒に対し、六フッ化リン酸リチウム（ＬｉＰＦ6）を溶解させた。ＬｉＰＦ6の濃度は、１モル／リットルとし非水電解液を得た。 [Preparation of non-aqueous electrolyte]
Under an argon atmosphere, fluoroethylene carbonate (FEC) and methyl ethyl carbonate (MEC) were mixed. The volume ratio (FEC: MEC) between fluoroethylene carbonate (FEC) and methyl ethyl carbonate (MEC) was 2: 8. Lithium hexafluorophosphate (LiPF 6 ) was dissolved in the obtained mixed solvent. The concentration of LiPF 6 was 1 mol / liter to obtain a non-aqueous electrolyte.
　〔電極体の作製〕
　正極と負極とを、厚さが２０μｍであるセパレータを介して対向させ、正極タブ及び負極タブが共に最外周となるように、円柱型の巻き芯を用いて、渦巻き状に巻回した。その後、巻き芯を引き抜いて、渦巻状の電極体を作製した。次に、渦巻き状の電極体を押し潰して、扁平型の電極体を得た。作製した扁平型の電極体の模式的斜視図を図３に示す。図３に示されるように、電極体３からは、正極集電タブ１及び負極集電タブ２のそれぞれの端部が取り出されている。なお、セパレータとして、ポリエチレン製微多孔膜を用いた。ポリエチレン製微多孔膜の長さは、４５０ｍｍであった。ポリエチレン製微多孔膜の幅は、５４．５ｍｍであった。ポリエチレン製微多孔膜の突き刺し強度は、３４０ｇであった。ポリエチレン製微多孔膜の空孔率は、４５％であった。 (Production of electrode body)
The positive electrode and the negative electrode were opposed to each other with a separator having a thickness of 20 μm, and the positive electrode tab and the negative electrode tab were wound in a spiral shape using a cylindrical core so that both of the positive electrode tab and the negative electrode tab were on the outermost periphery. Thereafter, the winding core was pulled out to produce a spiral electrode body. Next, the spiral electrode body was crushed to obtain a flat electrode body. A schematic perspective view of the produced flat electrode body is shown in FIG. As shown in FIG. 3, the end portions of the positive electrode current collecting tab 1 and the negative electrode current collecting tab 2 are taken out from the electrode body 3. A polyethylene microporous membrane was used as the separator. The length of the polyethylene microporous membrane was 450 mm. The width of the polyethylene microporous membrane was 54.5 mm. The piercing strength of the polyethylene microporous membrane was 340 g. The porosity of the polyethylene microporous membrane was 45%.
　〔電池の作製〕
　扁平型電極体及び非水電解液を、２５℃、１気圧の二酸化炭素雰囲気下でアルミニウムラミネート製の外装体内に挿入し、図４及び図５に示される構造を有する扁平型電池Ａ１を作製した。 [Production of battery]
The flat electrode body and the non-aqueous electrolyte were inserted into an aluminum laminate outer package in a carbon dioxide atmosphere at 25 ° C. and 1 atm to produce a flat battery A1 having the structure shown in FIGS. .
　電池Ａ１は、アルミニウムラミネートからなる外装体４を有する。外装体４は、アルミニウム箔の端部同士がヒートシールされた閉口部５を有する。電池Ａ１は、正極集電タブ１と、負極集電タブ２と、正極６及び負極７の間にセパレータ８を挟んだ状態で巻回された電極体３（扁平型電極体）とをさらに有する。 Battery A1 has an exterior body 4 made of an aluminum laminate. The exterior body 4 has the closing part 5 by which the edge parts of aluminum foil were heat-sealed. The battery A1 further includes a positive electrode current collector tab 1, a negative electrode current collector tab 2, and an electrode body 3 (flat electrode body) wound in a state where the separator 8 is sandwiched between the positive electrode 6 and the negative electrode 7. .
　〔Ｓｉ及びＳｉＯの膨張率の測定〕
　負極活物質粒子として用いたＳｉＯ（すなわちＳｉＯx（ｘ＝１．０））と、Ｓｉについて、充電時における膨張率を、以下のようにして測定した。 [Measurement of expansion coefficient of Si and SiO]
With respect to SiO (that is, SiO x (x = 1.0)) and Si used as the negative electrode active material particles, the expansion coefficient during charging was measured as follows.
　膨張率＝（充電状態の電極より合剤層を剥離して測定した体積）／（放電状態の電極より合剤層を剥離して測定した体積） Expansion rate = (volume measured by peeling the mixture layer from the charged electrode) / (volume measured by peeling the mixture layer from the discharged electrode)
　電極より合剤層を削りだし、削りだした合剤層の体積を島津製作所製乾式自動密度計（アキュピックII１３４０）にて測定した。 The mixture layer was shaved from the electrode, and the volume of the shaved mixture layer was measured with a Shimadzu dry automatic densimeter (Acupick II 1340).
　理論容量まで充電した時の膨張率は、Ｓｉは４００％、ＳｉＯは２２０％であった。 The expansion rate when charged to the theoretical capacity was 400% for Si and 220% for SiO.
　（比較例１）
　負極活物質として、ＳｉＯのみを用い、集電体の上に第２の合剤層のみを設けた負極を作製した。この負極を用いる以外は実施例１と同様にして、比較電池Ｂ１を作製した。なお、このときの第２の合剤層の質量は、３６．９ｍｇ／１０ｃｍ2であり、厚みは２４．６μｍであった。 (Comparative Example 1)
A negative electrode in which only the second mixture layer was provided on the current collector using only SiO as the negative electrode active material was produced. Comparative battery B1 was produced in the same manner as in Example 1 except that this negative electrode was used. In addition, the mass of the 2nd mixture layer at this time was 36.9 mg / 10cm < 2 >, and thickness was 24.6 micrometers.
　本比較例１における負極の容量は、上記実施例１の負極の容量と同じになるように調整している。 The capacity of the negative electrode in Comparative Example 1 is adjusted to be the same as the capacity of the negative electrode in Example 1 above.
　（比較例２）
　活物質として、ＳｉＯとＳｉとを質量比（ＳｉＯ：Ｓｉ）で２５：７５となるように混合した混合粉末を用い、集電体の上に活物質層を１層のみ形成した。このこと以外は、実施例１と同様にして、比較電池Ｂ２を作製した。本比較例２の電極における合剤層の質量は２１．３ｍｇ／１０ｃｍ2であり、厚みは１４．２μｍであった。 (Comparative Example 2)
As the active material, a mixed powder in which SiO and Si were mixed at a mass ratio (SiO: Si) of 25:75 was used, and only one active material layer was formed on the current collector. A comparative battery B2 was produced in the same manner as in Example 1 except for this. The mass of the mixture layer in the electrode of Comparative Example 2 was 21.3 mg / 10 cm 2 , and the thickness was 14.2 μm.
　本比較例２でも、実施例１の負極と同じ容量となるように調整している。 In Comparative Example 2, the same capacity as that of the negative electrode of Example 1 is adjusted.
　（比較例３）
　活物質としてのＳｉのみを用い、第１の合剤層のみを集電体の上に設けた以外は、上記実施例１と同様にして負極を作製し、この負極を用いて比較電池Ｂ３を作製した。この比較例３の電極の合剤層の質量は、１８．７ｍｇ／１０ｃｍ2であり、厚みは１２．５μｍであった。 (Comparative Example 3)
A negative electrode was produced in the same manner as in Example 1 except that only Si as the active material was used and only the first mixture layer was provided on the current collector. A comparative battery B3 was fabricated using this negative electrode. Produced. The mixture layer of the electrode of Comparative Example 3 had a mass of 18.7 mg / 10 cm 2 and a thickness of 12.5 μm.
　本比較例３においても、負極の容量が、実施例１と同様になるように調整している。 In Comparative Example 3, the negative electrode capacity is adjusted to be the same as in Example 1.
　〔走査型電子顕微鏡による負極断面の観察〕
　本発明に従う電池Ａ１及び比較電池Ｂ２の負極の断面の走査型電子顕微鏡（ＳＥＭ）写真をそれぞれ図２に示す。図２に示すように、電池Ａ１においては、Ａ層として示す第２の活物質層と、Ｂ層として示す第１の活物質層が形成されて２層構造になっていることがわかる。これに対して、比較電池Ｂ２では、第１の活物質と第２の活物質とが混合された１層構造であることがわかる。 [Observation of negative electrode cross section with scanning electron microscope]
The scanning electron microscope (SEM) photograph of the cross section of the negative electrode of battery A1 and comparative battery B2 according to this invention is shown in FIG. 2, respectively. As shown in FIG. 2, in the battery A1, it is found that the second active material layer shown as the A layer and the first active material layer shown as the B layer are formed to have a two-layer structure. On the other hand, it can be seen that the comparative battery B2 has a single-layer structure in which the first active material and the second active material are mixed.
　〔充放電サイクル特性の評価〕
　電池Ａ１、Ｂ１、Ｂ２及びＢ３のそれぞれについて、下記の充放電サイクル条件にて充放電サイクル特性を評価した。 [Evaluation of charge / discharge cycle characteristics]
For each of the batteries A1, B1, B2, and B3, the charge / discharge cycle characteristics were evaluated under the following charge / discharge cycle conditions.
　（充放電サイクル条件）
　・１サイクル目の充電条件
　５０ｍＡの電流で４時間定電流充電を行った。その後、２００ｍＡの電流で電池電圧が４．２Ｖとなるまで定電流充電を行った。さらに、４．２Ｖの電圧で電流値が５０ｍＡとなるまで定電圧充電を行った。 (Charge / discharge cycle conditions)
-Charging conditions in the first cycle Constant current charging was performed at a current of 50 mA for 4 hours. Thereafter, constant current charging was performed at a current of 200 mA until the battery voltage reached 4.2V. Furthermore, constant voltage charging was performed at a voltage of 4.2 V until the current value reached 50 mA.
　・１サイクル目の放電条件
　２００ｍＡの電流で電池電圧が２．７５Ｖとなるまで定電流放電を行った。 -First cycle discharge conditions Constant current discharge was performed at a current of 200 mA until the battery voltage reached 2.75V.
　・２サイクル目以降の充電条件
　１０００ｍＡの電流で電池電圧が４．２Ｖとなるまで定電流充電を行った。さらに、４．２Ｖの電圧で電流値が５０ｍＡとなるまで定電圧充電を行った。 -Charging conditions after the second cycle Constant current charging was performed until the battery voltage reached 4.2 V at a current of 1000 mA. Furthermore, constant voltage charging was performed at a voltage of 4.2 V until the current value reached 50 mA.
　・２サイクル目以降の放電条件
　１０００ｍＡの電流で電池電圧が２．７５Ｖとなるまで定電流放電を行った。 -Discharge condition after 2nd cycle Constant current discharge was performed until the battery voltage became 2.75 V at a current of 1000 mA.
　以下の計算方法で、サイクル寿命を求めた。 The cycle life was obtained by the following calculation method.
　・サイクル寿命；容量維持率が９０％になった時のサイクル数とした。 Cycle life: The number of cycles when the capacity maintenance rate reached 90%.
　１サイクル目の充放電効率を、初期充放電効率として表１に示した。 The charge / discharge efficiency at the first cycle is shown in Table 1 as the initial charge / discharge efficiency.
　また、サイクル寿命も表１に示した。 The cycle life is also shown in Table 1.
　なお、表１においては、比較例電池Ｂ３の初期充放電効率及びサイクル寿命を１００とした指数で示す。 In Table 1, the initial charge / discharge efficiency and the cycle life of Comparative Example Battery B3 are shown as indexes.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、本発明に従う電池Ａ１は、初期充放電効率及びサイクル寿命に優れていることがわかる。ＳｉＯのみを負極活物質として用いた比較電池Ｂ１では、サイクル寿命は高いが、初期充放電効率が低いことがわかる。また、Ｓｉのみを負極活物質として用いた比較電池Ｂ３においては、サイクル寿命が電池Ａ１よりも劣っていることがわかる。また、ＳｉＯとＳｉを混合して負極活物質として用いた比較電池Ｂ２においては、サイクル寿命が電池Ａ１に比べ劣っていることがわかる。 As shown in Table 1, it can be seen that the battery A1 according to the present invention is excellent in initial charge / discharge efficiency and cycle life. It can be seen that Comparative Battery B1 using only SiO as the negative electrode active material has a high cycle life but low initial charge / discharge efficiency. It can also be seen that the comparative battery B3 using only Si as the negative electrode active material has a cycle life inferior to that of the battery A1. In addition, it can be seen that the cycle life of the comparative battery B2 in which SiO and Si are mixed and used as the negative electrode active material is inferior to that of the battery A1.
　以上のことから、本発明によれば、初期充放電効率が高く、かつサイクル特性に優れたリチウム二次電池が得られることがわかる。 From the above, it can be seen that according to the present invention, a lithium secondary battery having high initial charge and discharge efficiency and excellent cycle characteristics can be obtained.
１…正極集電タブ
２…負極集電タブ
３…電極体
４…外装体
５…閉口部
６…正極
７…負極
８…セパレータ
１０…負極
１１…集電体
１２ａ，１２ｂ…第２の合剤層
１３ａ，１３ｂ…第１の合剤層 DESCRIPTION OF SYMBOLS 1 ... Positive electrode current collection tab 2 ... Negative electrode current collection tab 3 ... Electrode body 4 ... Exterior body 5 ... Closure part 6 ... Positive electrode 7 ... Negative electrode 8 ... Separator 10 ... Negative electrode 11 ... Current collector 12a, 12b ... 2nd mixture Layers 13a, 13b ... first mixture layer

Claims (6)

  1. 　集電体と、前記集電体上に設けられ、第１の活物質粒子及び第１のバインダーを含む第１の合剤層と、前記集電体上に設けられ、第２の活物質粒子及び第２のバインダーを含む第２の合剤層とを備え、
    　前記第２の合剤層は、前記第１の合剤層より前記集電体に近い側に設けられており、
    　前記第２の活物質粒子の充電時における膨張率が、前記第１の活物質粒子よりも小さい、リチウム二次電池用負極。     A current collector, a first mixture layer provided on the current collector and including first active material particles and a first binder, and a second active material particle provided on the current collector And a second mixture layer containing a second binder,
    The second mixture layer is provided closer to the current collector than the first mixture layer,
    A negative electrode for a lithium secondary battery, wherein an expansion coefficient during charging of the second active material particles is smaller than that of the first active material particles.
  2. 　前記第１の活物質粒子が、ＳｉまたはＳｉ合金から形成されている、請求項１に記載のリチウム二次電池用負極。 The negative electrode for a lithium secondary battery according to claim 1, wherein the first active material particles are formed of Si or a Si alloy.
  3. 　前記第２の活物質粒子が、ＳｉＯx（ｘ＝０．５～１．５）粒子である、請求項１または２に記載のリチウム二次電池用負極。 3. The negative electrode for a lithium secondary battery according to claim 1, wherein the second active material particles are SiO x (x = 0.5 to 1.5) particles.
  4. 　ＳｉＯx粒子の表面が、非晶質炭素で被覆されている、請求項３に記載のリチウム二次電池用負極。 The negative electrode for a lithium secondary battery according to claim 3, wherein the surface of the SiO x particles is coated with amorphous carbon.
  5. 　前記第１または第２のバインダーがポリイミドである、請求項１～４のいずれか１項に記載のリチウム二次電池用負極。 The negative electrode for a lithium secondary battery according to any one of claims 1 to 4, wherein the first or second binder is polyimide.
  6. 　正極と、請求項１～５のいずれか１項に記載の負極と、非水電解質とを備える、リチウム二次電池。 A lithium secondary battery comprising a positive electrode, the negative electrode according to any one of claims 1 to 5, and a non-aqueous electrolyte.
PCT/JP2013/005320 2012-09-27 2013-09-09 Negative electrode for lithium secondary batteries, and lithium secondary battery WO2014049985A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2012-214558 2012-09-27
JP2012214558A JP2015232921A (en) 2012-09-27 2012-09-27 Negative electrode for lithium secondary battery, and lithium secondary battery

Publications (1)

Publication Number Publication Date
WO2014049985A1 true WO2014049985A1 (en) 2014-04-03

Family

ID=50387432

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2013/005320 WO2014049985A1 (en) 2012-09-27 2013-09-09 Negative electrode for lithium secondary batteries, and lithium secondary battery

Country Status (2)

Country Link
JP (1) JP2015232921A (en)
WO (1) WO2014049985A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014148043A1 (en) * 2013-03-22 2014-09-25 三洋電機株式会社 Nonaqueous electrolyte secondary battery
CN106486639A (en) * 2015-09-01 2017-03-08 深圳市比克动力电池有限公司 A kind of lithium battery pole slice and preparation method thereof

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6941669B2 (en) * 2017-03-31 2021-09-29 パナソニック株式会社 Negative electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery
JP6897253B2 (en) * 2017-04-10 2021-06-30 トヨタ自動車株式会社 Negative electrode for lithium ion secondary battery
JP7112872B2 (en) 2018-03-30 2022-08-04 三洋電機株式会社 secondary battery
KR102386322B1 (en) * 2018-04-17 2022-04-14 주식회사 엘지에너지솔루션 Negative electrode for lithium secondary battery, preparing method thereof, and lithium secondary battery comprising the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003249211A (en) * 2002-02-26 2003-09-05 Nec Corp Negative electrode for secondary battery, manufacturing method of secondary battery and negative electrode for secondary battery
JP2004235057A (en) * 2003-01-31 2004-08-19 Sanyo Electric Co Ltd Negative electrode for lithium secondary battery, and the battery
JP2006107912A (en) * 2004-10-05 2006-04-20 Gs Yuasa Corporation:Kk Nonaqueous electrolyte secondary battery
JP2006164954A (en) * 2004-11-11 2006-06-22 Matsushita Electric Ind Co Ltd Negative electrode for lithium ion secondary battery, its manufacturing method, and lithium ion secondary battery using it
WO2009063902A1 (en) * 2007-11-12 2009-05-22 Hitachi Maxell, Ltd. Electrode for nonaqueous secondary battery, nonaqueous secondary battery using the same, and method for producing electrode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003249211A (en) * 2002-02-26 2003-09-05 Nec Corp Negative electrode for secondary battery, manufacturing method of secondary battery and negative electrode for secondary battery
JP2004235057A (en) * 2003-01-31 2004-08-19 Sanyo Electric Co Ltd Negative electrode for lithium secondary battery, and the battery
JP2006107912A (en) * 2004-10-05 2006-04-20 Gs Yuasa Corporation:Kk Nonaqueous electrolyte secondary battery
JP2006164954A (en) * 2004-11-11 2006-06-22 Matsushita Electric Ind Co Ltd Negative electrode for lithium ion secondary battery, its manufacturing method, and lithium ion secondary battery using it
WO2009063902A1 (en) * 2007-11-12 2009-05-22 Hitachi Maxell, Ltd. Electrode for nonaqueous secondary battery, nonaqueous secondary battery using the same, and method for producing electrode

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014148043A1 (en) * 2013-03-22 2014-09-25 三洋電機株式会社 Nonaqueous electrolyte secondary battery
CN106486639A (en) * 2015-09-01 2017-03-08 深圳市比克动力电池有限公司 A kind of lithium battery pole slice and preparation method thereof
CN106486639B (en) * 2015-09-01 2019-11-15 深圳市比克动力电池有限公司 A kind of lithium battery pole slice and preparation method thereof

Also Published As

Publication number Publication date
JP2015232921A (en) 2015-12-24

Similar Documents

Publication Publication Date Title
JP6237775B2 (en) Anode for non-aqueous electrolyte secondary battery
JP4027255B2 (en) Negative electrode for lithium secondary battery and method for producing the same
JP5219339B2 (en) Lithium secondary battery
JP5219340B2 (en) Negative electrode for lithium secondary battery, method for producing the same, and lithium secondary battery
JP4212392B2 (en) Negative electrode for lithium secondary battery and lithium secondary battery
JP4225727B2 (en) Negative electrode for lithium secondary battery and lithium secondary battery
US8211569B2 (en) Lithium secondary battery including a negative electrode which is a sintered layer of silicon particles and/or silicon alloy particles and a nonaqueous electrolyte containing carbon dioxide dissolved therein and method for producing same
JP5279018B2 (en) Lithium ion secondary battery and manufacturing method thereof
JP2010165471A (en) Lithium secondary battery
WO2014049985A1 (en) Negative electrode for lithium secondary batteries, and lithium secondary battery
US20060141359A1 (en) Lithium secondary battery
JP2009099523A (en) Lithium secondary battery
WO2015098023A1 (en) Negative electrode for non-aqueous electrolyte secondary cell
JP4497899B2 (en) Lithium secondary battery
JP4270894B2 (en) Negative electrode for lithium secondary battery and lithium secondary battery
US20110111302A1 (en) Electrode plate for nonaqueous electrolyte secondary battery, method for fabricating the same, and nonaqueous electrolyte secondary battery
JP6179404B2 (en) Manufacturing method of secondary battery
JP5945401B2 (en) Method for producing positive electrode current collector foil of lithium ion secondary battery
JP6447621B2 (en) Nonaqueous electrolyte secondary battery
JP2019175657A (en) Lithium ion secondary battery
JP4958405B2 (en) Nonaqueous electrolyte secondary battery
JP2012164481A (en) Nonaqueous electrolyte secondary battery and method for manufacturing the same
JP2018160379A (en) Negative electrode for lithium ion secondary battery and lithium ion secondary battery
JP2008235083A (en) Negative electrode for lithium secondary battery, and lithium secondary cell
JP5267976B2 (en) Negative electrode for lithium ion secondary battery and lithium ion secondary battery using the same

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: 13842477

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13842477

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP