WO2016157934A1 - Sodium-ion cell - Google Patents

Sodium-ion cell Download PDF

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Publication number
WO2016157934A1
WO2016157934A1 PCT/JP2016/050916 JP2016050916W WO2016157934A1 WO 2016157934 A1 WO2016157934 A1 WO 2016157934A1 JP 2016050916 W JP2016050916 W JP 2016050916W WO 2016157934 A1 WO2016157934 A1 WO 2016157934A1
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Prior art keywords
active material
electrode active
positive electrode
negative electrode
sodium ion
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PCT/JP2016/050916
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French (fr)
Japanese (ja)
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貴洋 松山
西島　主明
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シャープ株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • 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 sodium ion battery.
  • the present invention relates to a configuration of a sodium ion battery capable of achieving high output characteristics.
  • the sodium ion battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which sodium ions in the electrolyte bear electric conduction.
  • lithium ion battery As this type of non-aqueous electrolyte secondary battery, a lithium ion battery has already been put into practical use and is on the market. However, since lithium is a rare metal (rare metal) and the supply amount of raw materials is small, there is a problem that the price of the product is increased.
  • graphite which is generally used as a negative electrode material for lithium ion secondary batteries, is difficult to occlude and release sodium ions theoretically and practically because of its crystal structure.
  • the non-graphitizable carbon used for the negative electrode of a sodium ion battery has a problem that polarization is large at high output.
  • the time of high output means the case where the charge / discharge rate is 10 C or more.
  • Patent Document 1 a sodium ion battery disclosed in Patent Document 1 or Patent Document 2 is known.
  • the sodium battery disclosed in Patent Document 1 has a configuration in which a positive electrode member in which an active material portion including a Prussian blue-type cyano-bridged metal complex as an active material is formed on the surface of a conductive member is used. With this configuration, it is possible to provide a battery with high battery characteristics at low cost. That is, a complex compound typified by Prussian blue used as a positive electrode active material of a sodium ion battery can be expected to have high input / output without inhibiting sodium ion migration from its strong lattice.
  • the sodium secondary battery disclosed in Patent Document 2 includes a positive electrode that can be doped / undoped with sodium ions, a negative electrode that can be doped / undoped with sodium ions, and an electrolyte.
  • An inorganic porous layer containing an alumina filler having a sodium content of 0.01% by weight or more and 15% by weight or less in terms of oxide is formed on at least one surface of an electrode selected from.
  • Japanese Patent Publication Japanese Laid-Open Patent Publication No. 2013-152869 (Released on August 8, 2013)” Japanese Patent Publication “JP 2011-103277 A (published May 26, 2011)”
  • the conventional sodium ion battery has the following problems.
  • the sodium battery disclosed in Patent Document 1 has a problem that high output characteristics (10 C or more) cannot be expected because the negative electrode is sodium metal and is not non-graphitizable carbon. Moreover, there is no description about the density of the negative electrode that suppresses the polarization of the negative electrode and improves the discharge voltage even at a high output of 10 C or higher.
  • Non-Patent Document 1 is described in Patent Document 1 as a prior art, and Non-Patent Document 1 discloses that hard carbon is used as a negative electrode material of a sodium ion battery.
  • the charge / discharge rate is about 1.2C, and there is no opinion about high output of 10C or more.
  • the sodium secondary battery disclosed in Patent Document 2 has a problem that the positive electrode active material is a metal composite oxide and high output characteristics cannot be expected.
  • the positive electrode active material is limited to a metal composite oxide that can be doped / undoped with sodium ions.
  • the point that using non-graphitizable carbon for a negative electrode raises a charge / discharge rate characteristic is described, the numerical value of a specific charge / discharge rate characteristic is not mentioned.
  • the problem of the polarization of the negative electrode with respect to high output is not mentioned, and there is no description about the density of the negative electrode (non-graphitizable carbon).
  • the present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a sodium ion battery capable of achieving high output characteristics.
  • a sodium ion battery includes a positive electrode including a positive electrode active material capable of inserting and desorbing sodium ions, and non-graphite capable of inserting and desorbing sodium ions.
  • FIGS. 1 to 3 An embodiment of the present invention will be described with reference to FIGS. 1 to 3 as follows.
  • FIG. 2A is an exploded perspective view showing the configuration of the sodium ion battery 1 of the present embodiment
  • FIG. 2B is a perspective view showing the configuration of the sodium ion battery 1.
  • the sodium ion battery 1 of the present embodiment is a laminated battery type sodium ion secondary battery in which the single cell 10 is housed in the aluminum laminate films 2 and 3 as an example.
  • the present invention is not necessarily limited to the laminate battery type, and can be applied to, for example, a coin battery or the like.
  • the coin battery has a smaller ratio of members such as an active material to the battery container and a large excess of the electrolyte with respect to the active material as compared with the laminate battery type.
  • the sodium ion battery 1 of the present embodiment is composed of a single cell 10 sandwiched between two aluminum laminate films 2 and 3. . That is, the single cell 10 is sandwiched between two rectangular aluminum laminate films 2 and 3 from above and below, and in this state, the thermocompression bonding portions 2a and 2a on the outer periphery of the aluminum laminate films 2 and 3 are placed. They are thermocompression bonded to each other at 3a.
  • the single cell 10 is drawn from the positive electrode 11, the negative electrode 12, the separator 13 provided between the positive electrode 11 and the negative electrode 12, the positive electrode side aluminum tab lead 14 drawn from the positive electrode 11, and the negative electrode 12. And the negative electrode side aluminum tab lead 15.
  • the positive electrode side aluminum tab lead 14 and the negative electrode side aluminum tab lead 15 are bonded to the aluminum laminate films 2 and 3 by adhesive films 16 and 16, respectively.
  • the positive electrode 11 includes a positive electrode active material capable of inserting and desorbing sodium ions.
  • the insertion and desorption active material capable of sodium ions in the positive electrode 11 is represented by Na m M1 x M2 y (CN ) 6 ⁇ zH 2 O, the M1 and M2 transition metal And 0 ⁇ m ⁇ 2, 0.5 ⁇ x ⁇ 1.5, 0.5 ⁇ y ⁇ 1.5, 0 ⁇ z ⁇ 10 It has become.
  • the positive electrode active material is composed of a component different from the metal composite oxide, higher output characteristics can be expected as compared with the case where the positive electrode active material is a metal composite oxide.
  • the transition metal M1 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg. ing.
  • the transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg.
  • transition metal M1 and the transition metal M2 a combination of materials that can be expected to have high output characteristics can be selected.
  • the combination of the transition metal M1 and the transition metal M2 of the positive electrode active material is not necessarily limited to the above combination.
  • the transition metal M1 of the positive electrode active material is Mn or Fe.
  • the transition metal M2 of the active material can also be Fe.
  • transition metal M1 and the transition metal M2 a combination of materials that can be expected to have high output characteristics can be selected as described above.
  • the basis weight of the positive electrode active material is, for example, 6.7 to 13.3 mg / cm 2 .
  • the basis weight of the positive electrode active material is not necessarily limited thereto, and is not particularly limited as long as it is within the range of common sense.
  • the density of the positive electrode active material layer is, for example, 1.1 g / cm 3 .
  • the density of the positive electrode active material layer is not necessarily limited thereto, and is not particularly limited as long as it is within the range of common sense, but may be 0.5 g / cm 3 or more and 2.0 g / cm 3 or less. Preferably, it is 0.7 g / cm 3 or more and 1.8 g / cm 3 or less.
  • the negative electrode 12 has a negative electrode active material layer containing non-graphitizable carbon capable of inserting and desorbing sodium ions.
  • the density of non-graphitizable carbon that is, so-called hard carbon is set higher than that in the past. That is, the density of the conventional negative electrode active material layer is about 0.9 g / cm 3 as shown in Comparative Examples 1 to 3 described later, and there is a problem that the polarization is large at high output.
  • the density of the negative electrode active material layer is set to 0.95 so as to approach the true density of the non-graphitizable carbon. ⁇ 1.35 g / cm 3 , that is, 0.95 g / cm 3 or more and 1.35 g / cm 3 or less. More preferably, the negative electrode active material layer density in the vicinity of the peak value of the average discharge voltage is 1.1 to 1.3 g / cm 3 . Thereby, the sodium ion battery 1 which can aim at a higher output characteristic than before can be provided.
  • the density of the negative electrode active material layer is less than 0.95 g / cm 3 , the effect of improving the cell discharge voltage is small.
  • the density of the negative electrode active material layer exceeds 1.40 g / cm 3 , the diffusion resistance of sodium ion ions increases, resulting in a decrease in output and a desired effect.
  • the basis weight of the negative electrode active material is 2 to 8 mg / cm 2 , preferably 3 to 7 mg / cm 2 . That is, when the basis weight of the negative electrode active material is less than 2 mg / cm 2 , the coating property of the electrode paste is poor and the production efficiency is deteriorated. On the other hand, if the basis weight of the negative electrode active material exceeds 8 mg / cm 2 , the diffusion resistance of sodium ions increases, resulting in a decrease in output and the desired effect cannot be obtained.
  • the basis weight of the negative electrode active material layer is preferably 0.45 to 0.8 per unit area of the positive electrode active material layer.
  • the positive electrode active material is represented by Na m M1 x M2 y (CN) 6 ⁇ zH 2 O, M1 and M2 are transition metals, and 0 ⁇ m ⁇ 2, 0. 5 ⁇ x ⁇ 1.5, 0.5 ⁇ y ⁇ 1.5, and 0 ⁇ z ⁇ 10.
  • the weight of the negative electrode active material layer is: It has been found that the basis weight of the positive electrode active material layer is preferably 0.60 to 0.72 with respect to 1.
  • the electrolyte has sodium ion conductivity.
  • Na 4 Fe (CN) 6 ⁇ 10 (H 2 O), MnCl 2 ⁇ (4H 2 O), and NaCl are used as starting materials for the positive electrode material at a molar ratio of 1: 1: 5. Used.
  • MnCl 2 .4H 2 O which is a manganese source
  • NaCl sodium chloride
  • PVDF PolyVinylidene DiFluoride
  • NMP N-methyl pyrrolidone
  • carbon black B and the positive electrode active material A obtained in the above-described positive electrode active material preparation step were poured into and mixed with this NMP solution.
  • an electrode paste was obtained by stirring and mixing at room temperature using a thin film swirl type high speed mixer (trade name: Filmix (registered trademark) 40-40 type (manufactured by Primics Co., Ltd.)).
  • the electrode paste was applied on one side of a rolled aluminum foil having a thickness of 20 ⁇ m, and then dried in air at 100 ° C. for 30 minutes.
  • the positive electrode plate of Example (coated surface size: 28 mm (vertical) ⁇ 28 mm (horizontal)) was obtained as the positive electrode 11 by pressing.
  • the electrode density calculated from the thickness and weight of the electrode was adjusted to 1.1 g / cm 3 by adjusting the gap of a press (Thunk Metal 1-ton small precision roll press).
  • PVDF PolyVinylidene DiFluoride
  • NMP N-methylpyrrolidone
  • an electrode paste was obtained by stirring and kneading at room temperature using a biaxial planetary mixer (manufactured by Primex Corporation). This electrode paste was applied to one side of a rolled aluminum foil having a thickness of 20 ⁇ m, and then dried in air at 100 ° C. for 30 minutes.
  • the thickness of the electrode was changed by adjusting the gap of the press machine (Thunk Metal 1-ton small precision roll press), and the electrode density calculated from the thickness and weight was 0.9, 1.0, Electrodes of 1.1, 1.2 and 1.3 g / cm 3 were obtained.
  • the positive electrode 11 and the negative electrode 12 produced by the positive electrode production process and the negative electrode production process described above were dried under reduced pressure at 130 ° C. for 24 hours. Thereafter, after the positive electrode and the negative electrode are placed in a glow box in a dry Ar atmosphere, the positive electrode-side aluminum tab lead 14 and the negative electrode-side aluminum tab lead 15 with adhesive films 16 and 16 attached to the positive electrode 11 and the negative electrode 12, respectively. Were ultrasonically welded.
  • a polyolefin microporous film (manufactured by Celgard, size: 30 mm (length) ⁇ 30 cm (width), thickness 25 ⁇ m) is loaded as a separator 13 so that the coated surface 12a of the negative electrode 12 is hidden.
  • a single cell 10 was fabricated by stacking the positive electrode 11 so that the coated surface overlapped with the center.
  • the single cell 10 is sandwiched between the aluminum laminate films 2 and 3, and the adhesive films 16 and 16 of the positive electrode side aluminum tab lead 14 and the negative electrode side aluminum tab lead 15 are sandwiched between the three sides of the aluminum laminate films 2 and 3.
  • the thermocompression bonding parts 2a and 3a were thermally welded.
  • the aluminum laminate films 2 and 3 are in a bag shape.
  • NaPF 6 is added to a solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed at a volume ratio of 1: 2 so as to be 1 mol / l.
  • the sodium ion battery 1 was obtained by injecting the electrolyte solution in which the solution was dissolved into the single cell 10 and thermally fusing the last side of the aluminum laminate films 2 and 3 under a reduced pressure of 10 kPa.
  • the amount of electrolyte solution injected was such that the electrolyte solution sufficiently penetrated into the positive electrode 11, the negative electrode 12 and the separator 13 of the sodium ion battery 1.
  • FIG. 3 and FIG. 1 show the cell average discharge voltage when the positive electrode 11 and the negative electrode 12 of the produced single cell 10 are the basis weight, the layer thickness, and the electrode density in each example and comparative example.
  • FIG. 3 is a diagram showing the basis weight, the layer thickness, the electrode density, and the discharge average voltage of the positive electrode 11 and the negative electrode 12 in each example and comparative example of the produced single cell 10.
  • FIG. 1 is a graph plotting the relationship between the negative electrode active material layer density and the cell average discharge voltage in each Example and Comparative Example.
  • the average discharge voltage of the single cell 10 shown in FIG.1 and FIG.3 is the value measured by charging 0.1-C of the produced sodium ion battery 1 at 25 degreeC, and discharging at the discharge rate 10C.
  • the current calculated from the theoretical capacity in charge / discharge of the positive electrode 11 is charged or discharged in 1 h is 1 C.
  • the negative electrode active material layer density was 1 g / cm 3
  • Example 3 which is 84 (V)
  • the negative electrode active material layer density is 1.2 g / cm 3, it is 2.91 (V)
  • Example 4 where the negative electrode active material layer density is 1.3 g / cm 3 , It was 2.89 (V).
  • the density of the negative electrode active material layer was 0.95 to 1.35 g / cm 3
  • the cell average The discharge voltage was 2.4 (V) in Comparative Example 2 where the negative electrode active material layer density was 0.9 g / cm 3 , while in Example 5 where the negative electrode active material layer density was 1 g / cm 3.
  • Example 6 which is 2.57 (V) and the negative electrode active material layer density is 1.1 g / cm 3, it is 2.7 (V) and the negative electrode active material layer density is 1.2 g / cm 3.
  • Example 7 was 2.74 (V), and in Example 8 where the negative electrode active material layer density was 1.3 g / cm 3 , it was 2.71 (V).
  • Example 5 to 8 in which the density of the negative electrode active material layer was 0.95 to 1.35 g / cm 3 , it was possible to obtain a higher-power sodium ion battery 1 compared to Comparative Example 2. It could be confirmed.
  • the density of the positive electrode active material layer of the positive electrode 11 was set to 1.1 g / cm 3
  • the basis weight of the positive electrode 11 and 13.3 mg / cm 2 and the basis weight of the negative electrode 12 was set to 8 mg / cm 2
  • the cell average discharge voltage was 2.25 (V) in Comparative Example 3 having a negative electrode active material layer density of 0.9 g / cm 3
  • the negative electrode active material layer density was 1 g / cm 3.
  • Example 9 which is 2.35 (V)
  • Example 10 where the negative electrode active material layer density is 1.1 g / cm 3, it is 2.43 (V), and the negative electrode active material layer density is 1.2 g / cm 3.
  • Example 11 which is cm 3 , it was 2.43 (V)
  • Example 12 where the negative electrode active material layer density was 1.3 g / cm 3 , it was 2.32 (V).
  • the density of the negative electrode active material layer was 0.95 to 1.35 g / cm 3 , it was possible to obtain a higher-power sodium ion battery 1 compared to Comparative Example 3. It could be confirmed.
  • the high density sodium ion can be obtained by setting the density of the negative electrode active material layer to 0.95 to 1.35 g / cm 3 , more preferably 1.1 to 1.3 g / cm 3. It was confirmed that the battery 1 was obtained.
  • the basis weight of the negative electrode active material layer was preferably 7 mg / cm 2 or less.
  • the sodium ion battery 1 of the present embodiment includes the positive electrode 11 including the positive electrode active material capable of inserting and desorbing sodium ions, and the non-graphitizable carbon capable of inserting and desorbing sodium ions.
  • a negative electrode 12 having a negative electrode active material layer and an electrolyte having sodium ion conductivity are included.
  • the density of the negative electrode active material layer is 0.95 g / cm 3 or more and 1.35 g / cm 3 or less.
  • the conventional negative electrode active material layer containing non-graphitizable carbon has a problem that the density is, for example, about 0.9 g / cm 3 and the polarization is large at high output.
  • the density of the negative electrode active material layer is 0.95 g / cm 3 or more and 1.35 g / cm 3 or less, the sodium ion battery 1 that can achieve higher output characteristics than conventional ones. Can be provided.
  • the positive electrode active material capable of inserting and removing sodium ions in the positive electrode 11 is represented by Na m M1 x M2 y (CN) 6 ⁇ zH 2 O.
  • M1 and M2 are transition metals, 0 ⁇ m ⁇ 2, 0.5 ⁇ x ⁇ 1.5, 0.5 ⁇ y ⁇ 1.5, 0 ⁇ z ⁇ 10 It is.
  • a positive electrode active material is comprised by the component different from a metal complex oxide, compared with the case where a positive electrode active material is a metal complex oxide, it can expect a high output characteristic. it can.
  • the transition metal M1 of the positive electrode active material is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg.
  • the transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg. .
  • transition metal M1 and the transition metal M2 a combination of materials that can be expected to have high output characteristics can be selected as the transition metal M1 and the transition metal M2.
  • the transition metal M1 of the positive electrode active material can be Mn or Fe
  • the transition metal M2 of the positive electrode active material can be Fe
  • the basis weight of the negative electrode active material layer is 7 mg / cm 2 or less.
  • a sodium ion battery 1 according to aspect 1 of the present invention includes a positive electrode 11 including a positive electrode active material capable of inserting and desorbing sodium ions, and a negative electrode active material including non-graphitizable carbon capable of inserting and desorbing sodium ions.
  • a sodium ion battery including a negative electrode 12 having a layer and an electrolyte having sodium ion conductivity, wherein the density of the negative electrode active material layer is 0.95 g / cm 3 or more and 1.35 g / cm 3 or less. It is a feature.
  • the density of the said negative electrode active material layer is 0.95 g / cm ⁇ 3 > or more and 1.35 g / cm ⁇ 3 > or less.
  • the conventional negative electrode active material layer containing non-graphitizable carbon has a problem that the density is, for example, about 0.9 g / cm 3 and the polarization is large at high output.
  • the sodium ion battery 1 according to aspect 2 of the present invention is the sodium ion battery according to aspect 1, wherein the positive electrode active material capable of inserting and desorbing sodium ions in the positive electrode 11 is Na m M1 x M2 y (CN) 6.
  • the positive electrode active material capable of inserting and desorbing sodium ions in the positive electrode 11 is Na m M1 x M2 y (CN) 6.
  • M1 and M2 are transition metals, 0 ⁇ m ⁇ 2, 0.5 ⁇ x ⁇ 1.5, 0.5 ⁇ y ⁇ 1.5, 0 ⁇ z ⁇ 10 It is preferable that
  • cathode active material is represented by Na m M1 x M2 y (CN ) 6 ⁇ H 2 O.
  • the positive electrode active material is composed of a component different from the metal composite oxide, higher output characteristics can be expected as compared with the case where the positive electrode active material is a metal composite oxide.
  • the sodium ion battery 1 according to aspect 3 of the present invention is the sodium ion battery according to aspect 2, wherein the transition metal M1 of the positive electrode active material is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca,
  • the transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Mg, and is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, Mg. It may be at least one selected.
  • transition metal M1 and the transition metal M2 a combination of materials that can be expected to have high output characteristics can be selected as the transition metal M1 and the transition metal M2.
  • the combination of the same kind metal with transition metal M1: Ti and transition metal M2: Ti may be sufficient.
  • a sodium ion battery 1 according to Aspect 4 of the present invention is the sodium ion battery according to Aspect 2, wherein the transition metal M1 of the positive electrode active material is Mn or Fe, and the transition metal M2 of the positive electrode active material is Fe. can do.
  • transition metal M1 and the transition metal M2 a combination of materials that can be expected to have high output characteristics can be selected as the transition metal M1 and the transition metal M2.
  • a combination of the same metals as transition metal M1: Fe and transition metal M2: Fe may be used.
  • the basis weight of the negative electrode active material layer is preferably 7 mg / cm 2 or less in the sodium ion battery according to any one of the second to fourth aspects.
  • the present invention relates to a positive electrode including a positive electrode active material capable of inserting and desorbing sodium ions, a negative electrode having a negative electrode active material layer including non-graphitizable carbon capable of inserting and desorbing sodium ions, and sodium ion conductivity.
  • the present invention can be applied to a sodium ion battery including an electrolyte having a property.

Abstract

Provided is a sodium-ion cell with which it is possible to achieve high output characteristics. A sodium-ion cell (1) includes: a positive electrode (11) including a positive-electrode active material with which sodium ions can be inserted and desorbed; a negative electrode (12) including a negative-electrode active material layer that includes a non-graphitizable carbon with which sodium ions can be inserted and desorbed; and an electrolyte having sodium-ion conductivity. The density of the negative-electrode active material layer is 0.95 g/cm3 to 1.3 g/cm3.

Description

ナトリウムイオン電池Sodium ion battery
　本発明は、ナトリウムイオン電池に関するものである。特に、高出力特性を図り得るナトリウムイオン電池の構成に関する。 The present invention relates to a sodium ion battery. In particular, the present invention relates to a configuration of a sodium ion battery capable of achieving high output characteristics.
　ナトリウムイオン電池は、非水電解質二次電池の一種であり、電解質中のナトリウムイオンが電気伝導を担う二次電池である。 The sodium ion battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which sodium ions in the electrolyte bear electric conduction.
　この種の非水電解質二次電池としては、リチウムイオン電池が既に実用化されて市場に出回っている。しかしながら、リチウムはレアメタル（希少金属）であり、原料の供給量が少ないことから、製品の高価格化を招来するという問題点を有している。 As this type of non-aqueous electrolyte secondary battery, a lithium ion battery has already been put into practical use and is on the market. However, since lithium is a rare metal (rare metal) and the supply amount of raw materials is small, there is a problem that the price of the product is increased.
　そこで、この問題を解決するために、近年、リチウムに代えてナトリウムを使用するナトリウムイオン電池の開発が盛んになってきている。ナトリウムはリチウムに対して標準電極電位が約０．３Ｖ高く、起電力が若干劣るが、海水に豊富に存在することから原料が安く、低コスト化が図り易い。 Therefore, in order to solve this problem, in recent years, development of sodium ion batteries using sodium instead of lithium has become active. Sodium has a standard electrode potential of about 0.3 V higher than that of lithium, and the electromotive force is slightly inferior. However, since it is abundant in seawater, raw materials are cheap and cost reduction is easy.
　一方、ナトリウムはリチウムに対して、イオン体積にして２倍以上、原子量にして３倍以上大きいため、リチウムイオン二次電池用電極活物質の探索指針をそのまま流用することができない。 On the other hand, since sodium is larger than lithium in terms of ion volume by 2 times or more and in atomic weight by 3 times or more, the search guidelines for electrode active materials for lithium ion secondary batteries cannot be used as they are.
　例えば、一般にリチウムイオン二次電池用負極材として用いられる黒鉛は、その結晶構造ゆえに理論的にも実際にもナトリウムイオンを吸蔵放出させることが困難とされている。また、ナトリウムイオン電池の負極に用いられる難黒鉛化炭素は高出力時に分極が大きいという課題があった。 For example, graphite, which is generally used as a negative electrode material for lithium ion secondary batteries, is difficult to occlude and release sodium ions theoretically and practically because of its crystal structure. Moreover, the non-graphitizable carbon used for the negative electrode of a sodium ion battery has a problem that polarization is large at high output.
　その一方で、ナトリウムイオン電池の開発においては、高出力に特化した負極が求められている。尚、高出力時とは、充放電レート１０Ｃ以上の場合をいう。 On the other hand, in the development of sodium ion batteries, a negative electrode specialized for high output is required. In addition, the time of high output means the case where the charge / discharge rate is 10 C or more.
　ここで、ナトリウムイオン電池に関する従来技術としては、例えば特許文献１又は特許文献２に開示されたナトリウムイオン電池が知られている。 Here, as a conventional technique related to a sodium ion battery, for example, a sodium ion battery disclosed in Patent Document 1 or Patent Document 2 is known.
　特許文献１に開示されたナトリウム電池は、導電部材の表面に、活物質としてのプルシアンブルー型のシアノ架橋金属錯体を含む活物質部が形成された正極部材を用いるという構成を有している。そして、この構成により、低コストで電池特性の高い電池を提供することができるとしている。すなわち、ナトリウムイオン電池の正極活物質として用いられるプルシアンブルーで代表される錯体系化合物は、その強固な格子からナトリウムイオンの移動を阻害せず、高入出力が期待できる。 The sodium battery disclosed in Patent Document 1 has a configuration in which a positive electrode member in which an active material portion including a Prussian blue-type cyano-bridged metal complex as an active material is formed on the surface of a conductive member is used. With this configuration, it is possible to provide a battery with high battery characteristics at low cost. That is, a complex compound typified by Prussian blue used as a positive electrode active material of a sodium ion battery can be expected to have high input / output without inhibiting sodium ion migration from its strong lattice.
　また、特許文献２に開示されたナトリウム二次電池では、ナトリウムイオンをドープ・脱ドープすることのできる正極と、ナトリウムイオンをドープ・脱ドープすることのできる負極と電解質とを備え、正極及び負極から選ばれる電極の少なくとも一方の表面に、ナトリウム含有率が酸化物換算で０．０１重量％以上かつ１５重量％以下のアルミナフィラーを含む無機多孔層が形成された構成を有している。そして、この構成により、急速に充放電を行った場合の放電容量が大きい、つまり充放電レート特性に優れるという効果を奏するものとなっている。 In addition, the sodium secondary battery disclosed in Patent Document 2 includes a positive electrode that can be doped / undoped with sodium ions, a negative electrode that can be doped / undoped with sodium ions, and an electrolyte. An inorganic porous layer containing an alumina filler having a sodium content of 0.01% by weight or more and 15% by weight or less in terms of oxide is formed on at least one surface of an electrode selected from. And by this structure, there exists an effect that the discharge capacity at the time of performing charging / discharging rapidly is large, ie, it is excellent in a charge / discharge rate characteristic.
日本国公開特許公報「特開２０１３－１５２８６９号公報（２０１３年８月８日公開）」Japanese Patent Publication “Japanese Laid-Open Patent Publication No. 2013-152869 (Released on August 8, 2013)” 日本国公開特許公報「特開２０１１－１０３２７７号公報（２０１１年５月２６日公開）」Japanese Patent Publication “JP 2011-103277 A (published May 26, 2011)”
　しかしながら、上記従来のナトリウムイオン電池では、以下の問題点を有している。 However, the conventional sodium ion battery has the following problems.
　まず、特許文献１に開示されたナトリウム電池では、負極がナトリウム金属であり難黒鉛化炭素ではないので、高出力特性（１０Ｃ以上）が期待できないという問題点を有している。また、１０Ｃ以上の高出力時においても、負極の分極を抑制し、放電電圧が向上する負極の密度について記載が無い。 First, the sodium battery disclosed in Patent Document 1 has a problem that high output characteristics (10 C or more) cannot be expected because the negative electrode is sodium metal and is not non-graphitizable carbon. Moreover, there is no description about the density of the negative electrode that suppresses the polarization of the negative electrode and improves the discharge voltage even at a high output of 10 C or higher.
　尚、特許文献１には、従来技術として非特許文献１が記載されており、非特許文献１では、ナトリウムイオン電池の負極材料にハードカーボンが使用されていることが開示されている。しかし、充放電レートが１．２Ｃ程度であり、１０Ｃ以上の高出力時についての見解はない。 Incidentally, Non-Patent Document 1 is described in Patent Document 1 as a prior art, and Non-Patent Document 1 discloses that hard carbon is used as a negative electrode material of a sodium ion battery. However, the charge / discharge rate is about 1.2C, and there is no opinion about high output of 10C or more.
　また、特許文献２に開示されたナトリウム二次電池では、正極活物質が金属複合酸化物であり、高出力特性が期待できないという問題点を有している。 Also, the sodium secondary battery disclosed in Patent Document 2 has a problem that the positive electrode active material is a metal composite oxide and high output characteristics cannot be expected.
　すなわち、特許文献２では、正極活物質がナトリウムイオンをドープ・脱ドープすることのできる金属複合酸化物に限定されている。また、負極に難黒鉛化炭素を用いることが、充放電レート特性を高めるという点が記載されているが、具体的な充放電レート特性の数値については言及されていない。さらに、高出力に対する負極の分極の課題については触れておらず、負極(難黒鉛化炭素)の密度についての記載もない。 That is, in Patent Document 2, the positive electrode active material is limited to a metal composite oxide that can be doped / undoped with sodium ions. Moreover, although the point that using non-graphitizable carbon for a negative electrode raises a charge / discharge rate characteristic is described, the numerical value of a specific charge / discharge rate characteristic is not mentioned. Furthermore, the problem of the polarization of the negative electrode with respect to high output is not mentioned, and there is no description about the density of the negative electrode (non-graphitizable carbon).
　本発明は、上記従来の問題点に鑑みなされたものであって、その目的は、高出力特性を図り得るナトリウムイオン電池を提供することにある。 The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a sodium ion battery capable of achieving high output characteristics.
　本発明の一態様におけるナトリウムイオン電池は、上記の課題を解決するために、ナトリウムイオンの挿入及び脱離が可能な正極活物質を含む正極と、ナトリウムイオンの挿入及び脱離が可能な難黒鉛化炭素を含む負極活物質層を有する負極と、ナトリウムイオン導電性を有する電解質を含むナトリウムイオン電池であって、前記負極活物質層の密度が０．９５～１．３５ｇ／ｃｍ３であることを特徴としている。 In order to solve the above problems, a sodium ion battery according to one embodiment of the present invention includes a positive electrode including a positive electrode active material capable of inserting and desorbing sodium ions, and non-graphite capable of inserting and desorbing sodium ions. A negative electrode having a negative electrode active material layer containing carbonized carbon and a sodium ion battery containing an electrolyte having sodium ion conductivity, wherein the negative electrode active material layer has a density of 0.95 to 1.35 g / cm 3. It is characterized by.
　本発明の一態様によれば、高出力特性を図り得るナトリウムイオン電池を提供するという効果を奏する。 According to one aspect of the present invention, there is an effect of providing a sodium ion battery capable of achieving high output characteristics.
本発明の実施形態１におけるナトリウムイオン電池の各実施例及び比較例の負極活物質層密度とセル平均放電電圧との関係をプロットしたグラフである。It is the graph which plotted the relationship between the negative electrode active material layer density of each Example of a sodium ion battery in Embodiment 1 of this invention, and a comparative example, and a cell average discharge voltage. （ａ）は上記ナトリウムイオン電池の構成を示す分解斜視図であり、（ｂ）は上記ナトリウムイオン電池の構成を示す斜視図である。(A) is a disassembled perspective view which shows the structure of the said sodium ion battery, (b) is a perspective view which shows the structure of the said sodium ion battery. 上記ナトリウムイオン電池における作製した単セルの各実施例及び比較例の正極及び負極の目付量、層厚、電極密度、及び放電平均電圧を示す図である。It is a figure which shows the amount per unit area of the positive electrode and negative electrode of each Example of the single cell produced in the said sodium ion battery, and a comparative example, layer thickness, an electrode density, and a discharge average voltage.
　本発明の一実施形態について図１～図３に基づいて説明すれば、以下のとおりである。 An embodiment of the present invention will be described with reference to FIGS. 1 to 3 as follows.
　本実施の形態のナトリウムイオン電池１の構成について、図２の（ａ）（ｂ）に基づいて説明する。図２の（ａ）は、本実施の形態のナトリウムイオン電池１の構成を示す分解斜視図であり、図２の（ｂ）は上記ナトリウムイオン電池１の構成を示す斜視図である。 The configuration of the sodium ion battery 1 according to the present embodiment will be described with reference to FIGS. FIG. 2A is an exploded perspective view showing the configuration of the sodium ion battery 1 of the present embodiment, and FIG. 2B is a perspective view showing the configuration of the sodium ion battery 1.
　尚、本実施の形態のナトリウムイオン電池１は、一例として、単セル１０がアルミラミネートフィルム２・３に収納されたラミネート電池型のナトリウムイオン二次電池となっている。しかし、本発明においては、必ずしもラミネート電池型に限らず、例えばコイン電池又はその他であっても適用が可能である。ただし、コイン電池は、ラミネート電池型に比べて、電池容器に対して活物質等の部材の割合が小さく、かつ活物質に対して電解液が大過剰である。 The sodium ion battery 1 of the present embodiment is a laminated battery type sodium ion secondary battery in which the single cell 10 is housed in the aluminum laminate films 2 and 3 as an example. However, the present invention is not necessarily limited to the laminate battery type, and can be applied to, for example, a coin battery or the like. However, the coin battery has a smaller ratio of members such as an active material to the battery container and a large excess of the electrolyte with respect to the active material as compared with the laminate battery type.
　本実施の形態のナトリウムイオン電池１は、図２の（ａ）（ｂ）に示すように、２枚のアルミラミネートフィルム２・３の間に、単セル１０が挟持されたものからなっている。すなわち、単セル１０は２枚の方形のアルミラミネートフィルム２・３にて上下方向から挟まれた状態となっており、その状態で、アルミラミネートフィルム２・３の外周部における熱圧着部２ａ・３ａにて互いに熱圧着されている。 As shown in FIGS. 2A and 2B, the sodium ion battery 1 of the present embodiment is composed of a single cell 10 sandwiched between two aluminum laminate films 2 and 3. . That is, the single cell 10 is sandwiched between two rectangular aluminum laminate films 2 and 3 from above and below, and in this state, the thermocompression bonding portions 2a and 2a on the outer periphery of the aluminum laminate films 2 and 3 are placed. They are thermocompression bonded to each other at 3a.
　上記単セル１０は、正極１１と、負極１２と、これら正極１１と負極１２との間に設けられたセパレータ１３と、正極１１から引き出された正極側アルミニウム製タブリード１４と、負極１２から引き出された負極側アルミニウム製タブリード１５とから構成されている。上記正極側アルミニウム製タブリード１４及び負極側アルミニウム製タブリード１５は、接着フィルム１６・１６によって、それぞれアルミラミネートフィルム２・３に接着されている。 The single cell 10 is drawn from the positive electrode 11, the negative electrode 12, the separator 13 provided between the positive electrode 11 and the negative electrode 12, the positive electrode side aluminum tab lead 14 drawn from the positive electrode 11, and the negative electrode 12. And the negative electrode side aluminum tab lead 15. The positive electrode side aluminum tab lead 14 and the negative electrode side aluminum tab lead 15 are bonded to the aluminum laminate films 2 and 3 by adhesive films 16 and 16, respectively.
　本実施の形態では、正極１１は、ナトリウムイオンの挿入及び脱離が可能な正極活物質を含むものとなっている。 In the present embodiment, the positive electrode 11 includes a positive electrode active material capable of inserting and desorbing sodium ions.
　具体的には、正極１１中のナトリウムイオンの挿入及び脱離が可能な正極活物質が、ＮａｍＭ１ｘＭ２ｙ（ＣＮ）６・ｚＨ２Ｏにて表わされ、Ｍ１及びＭ２は遷移金属であり、
　０＜ｍ≦２、０．５≦ｘ≦１．５、０．５≦ｙ≦１．５、０＜ｚ≦１０
となっている。 Specifically, the insertion and desorption active material capable of sodium ions in the positive electrode 11 is represented by Na m M1 x M2 y (CN ) 6 · zH 2 O, the M1 and M2 transition metal And
0 <m ≦ 2, 0.5 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.5, 0 <z ≦ 10
It has become.
　これにより、正極活物質は、金属複合酸化物とは異なる成分にて構成されているので、正極活物質が金属複合酸化物ある場合に比べて高出力特性を期待することができる。 Thereby, since the positive electrode active material is composed of a component different from the metal composite oxide, higher output characteristics can be expected as compared with the case where the positive electrode active material is a metal composite oxide.
　特に、本実施の形態では、正極活物質の遷移金属Ｍ１は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種となっている。また、正極活物質の遷移金属Ｍ２は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種となっている。 In particular, in the present embodiment, the transition metal M1 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg. ing. The transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg.
　これにより、遷移金属Ｍ１及び遷移金属Ｍ２として、高出力特性が期待できる材料の組み合わせを選択することができるものとなっている。 Thereby, as the transition metal M1 and the transition metal M2, a combination of materials that can be expected to have high output characteristics can be selected.
　尚、本実施の形態では、正極活物質の遷移金属Ｍ１及び遷移金属Ｍ２の組み合わせは、必ずしも上記の組み合わせに限らず、は、例えば、正極活物質の遷移金属Ｍ１はＭｎ又はＦｅであり、正極活物質の遷移金属Ｍ２は、Ｆｅであるとすることも可能である。 In the present embodiment, the combination of the transition metal M1 and the transition metal M2 of the positive electrode active material is not necessarily limited to the above combination. For example, the transition metal M1 of the positive electrode active material is Mn or Fe. The transition metal M2 of the active material can also be Fe.
　これにより、遷移金属Ｍ１及び遷移金属Ｍ２として、前記と同様に、高出力特性が期待できる材料の組み合わせを選択することができる。 Thereby, as the transition metal M1 and the transition metal M2, a combination of materials that can be expected to have high output characteristics can be selected as described above.
　また、本実施の形態では、正極活物質の目付量を、例えば６．７～１３．３ｍｇ／ｃｍ２としている。しかし、正極活物質の目付量は、必ずしもこれに限らず、常識の範囲であれば特に限定されることはない。 In the present embodiment, the basis weight of the positive electrode active material is, for example, 6.7 to 13.3 mg / cm 2 . However, the basis weight of the positive electrode active material is not necessarily limited thereto, and is not particularly limited as long as it is within the range of common sense.
　さらに、本実施の形態では、正極活物質層の密度を、例えば１．１ｇ／ｃｍ３としている。しかし、正極活物質層の密度は、必ずしもこれに限らず、常識の範囲であれば特に限定されることはないが、０．５ｇ／ｃｍ３以上かつ２．０ｇ／ｃｍ３以下であることが好ましく、０．７ｇ／ｃｍ３以上かつ１．８ｇ／ｃｍ３以下であることがさらに好ましい。 Furthermore, in this embodiment, the density of the positive electrode active material layer is, for example, 1.1 g / cm 3 . However, the density of the positive electrode active material layer is not necessarily limited thereto, and is not particularly limited as long as it is within the range of common sense, but may be 0.5 g / cm 3 or more and 2.0 g / cm 3 or less. Preferably, it is 0.7 g / cm 3 or more and 1.8 g / cm 3 or less.
　次に、本実施の形態では、負極１２は、ナトリウムイオンの挿入及び脱離が可能な難黒鉛化炭素を含む負極活物質層を有するものとなっている。 Next, in the present embodiment, the negative electrode 12 has a negative electrode active material layer containing non-graphitizable carbon capable of inserting and desorbing sodium ions.
　具体的には、本実施の形態では、難黒鉛化炭素、所謂ハードカーボンの密度を従来よりも大きくしている。すなわち、従来の負極活物質層の密度は、後述する比較例１～３に示すように、０．９ｇ／ｃｍ３程度であり、高出力時に分極が大きいという課題があった。 Specifically, in the present embodiment, the density of non-graphitizable carbon, that is, so-called hard carbon is set higher than that in the past. That is, the density of the conventional negative electrode active material layer is about 0.9 g / cm 3 as shown in Comparative Examples 1 to 3 described later, and there is a problem that the polarization is large at high output.
　そこで、本実施の形態では、難黒鉛化炭素の真密度が１．５ｇ／ｃｍ３程度であることから、この難黒鉛化炭素の真密度に近づけるべく、負極活物質層の密度を０．９５～１．３５ｇ／ｃｍ３、つまり０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下であるとしている。より好ましくは、平均放電電圧のピーク値近傍の負極活物質層密度である１．１～１．３ｇ／ｃｍ３とするのがよい。これにより、従来よりも高出力特性を図り得るナトリウムイオン電池１を提供することができるものとなる。 Therefore, in this embodiment, since the true density of the non-graphitizable carbon is about 1.5 g / cm 3 , the density of the negative electrode active material layer is set to 0.95 so as to approach the true density of the non-graphitizable carbon. ˜1.35 g / cm 3 , that is, 0.95 g / cm 3 or more and 1.35 g / cm 3 or less. More preferably, the negative electrode active material layer density in the vicinity of the peak value of the average discharge voltage is 1.1 to 1.3 g / cm 3 . Thereby, the sodium ion battery 1 which can aim at a higher output characteristic than before can be provided.
　すなわち、負極活物質層の密度が０．９５ｇ／ｃｍ３未満では、セル放電電圧の向上の効果が小さい。一方、負極活物質層の密度が１．４０ｇ／ｃｍ３を超えると、ナトリウムイオンイオンの拡散抵抗が上がり、その結果、出力低下を招き、所望の効果を得ることができる。 That is, when the density of the negative electrode active material layer is less than 0.95 g / cm 3 , the effect of improving the cell discharge voltage is small. On the other hand, when the density of the negative electrode active material layer exceeds 1.40 g / cm 3 , the diffusion resistance of sodium ion ions increases, resulting in a decrease in output and a desired effect.
　また、本実施の形態では、負極活物質の目付量を、２～８ｍｇ／ｃｍ２、好ましくは３～７ｍｇ／ｃｍ２としている。すなわち、負極活物質の目付量を２ｍｇ／ｃｍ２未満とした場合には、電極ペーストの塗工性が悪く、製造効率が悪くなる。一方、負極活物質の目付量が８ｍｇ／ｃｍ２を超えるとした場合には、ナトリウムイオンの拡散抵抗が上がり、その結果、出力低下を招き、所望の効果を得ることができない。 In this embodiment, the basis weight of the negative electrode active material is 2 to 8 mg / cm 2 , preferably 3 to 7 mg / cm 2 . That is, when the basis weight of the negative electrode active material is less than 2 mg / cm 2 , the coating property of the electrode paste is poor and the production efficiency is deteriorated. On the other hand, if the basis weight of the negative electrode active material exceeds 8 mg / cm 2 , the diffusion resistance of sodium ions increases, resulting in a decrease in output and the desired effect cannot be obtained.
　ところで、負極活物質層の目付量は、正極活物質層の目付量が１に対して０．４５～０．８であることが好ましいことがわかっている。特に、本実施の形態では、正極活物質が、ＮａｍＭ１ｘＭ２ｙ（ＣＮ）６・ｚＨ２Ｏにて表わされ、Ｍ１及びＭ２は遷移金属であり、０＜ｍ≦２、０．５≦ｘ≦１．５、０．５≦ｙ≦１．５、０＜ｚ≦１０となっている。 By the way, it has been found that the basis weight of the negative electrode active material layer is preferably 0.45 to 0.8 per unit area of the positive electrode active material layer. In particular, in the present embodiment, the positive electrode active material is represented by Na m M1 x M2 y (CN) 6 · zH 2 O, M1 and M2 are transition metals, and 0 <m ≦ 2, 0. 5 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.5, and 0 <z ≦ 10.
　したがって、正極１１の充放電の容量が１５０ｍＡｈ／ｇ程度であるので、負極１２の難黒鉛化炭素の充放電の容量が２５０ｍＡｈ／ｇであることを考慮すると、負極活物資層の目付量は、正極活物質層の目付量が１に対して０．６０～０．７２が好ましいことが分かっている。 Therefore, since the charge / discharge capacity of the positive electrode 11 is about 150 mAh / g, considering the charge / discharge capacity of the non-graphitizable carbon of the negative electrode 12 is 250 mAh / g, the weight of the negative electrode active material layer is: It has been found that the basis weight of the positive electrode active material layer is preferably 0.60 to 0.72 with respect to 1.
　また、本実施の形態の単セル１０では、電解質は、ナトリウムイオン導電性を有するものとなっている。 Further, in the single cell 10 of the present embodiment, the electrolyte has sodium ion conductivity.
　上記構成のナトリウムイオン電池１における製造方法について、以下に説明する。 A manufacturing method in the sodium ion battery 1 having the above configuration will be described below.
　〔正極活物質の作製〕
　本実施の形態では、正極材料の出発原料として、Ｎａ４Ｆｅ（ＣＮ）６・１０（Ｈ２Ｏ）とＭｎＣｌ２・（４Ｈ２Ｏ）とＮａＣｌとを、モル比で１：１：５にて使用した。 [Preparation of positive electrode active material]
In the present embodiment, Na 4 Fe (CN) 6 · 10 (H 2 O), MnCl 2 · (4H 2 O), and NaCl are used as starting materials for the positive electrode material at a molar ratio of 1: 1: 5. Used.
　まず、マンガン源であるＭｎＣｌ２・４Ｈ２ＯとＮａＣｌとを、イオン交換水に一緒に投入して撹拌し、９０℃に加熱して混合液を作成した。 First, MnCl 2 .4H 2 O, which is a manganese source, and NaCl were added together in ion-exchanged water, stirred, and heated to 90 ° C. to prepare a mixed solution.
　次いで、Ｎａ４Ｆｅ（ＣＮ）６・１０Ｈ２Ｏをイオン交換水に溶解し、上記混合液に滴下投入し、９０℃にて６ｈ撹拌させた。その後、濾過し、濾物をイオン交換水にて洗浄後、アセトンにて洗浄した。次いで、その液を、１２０℃にて４８ｈ乾燥し、得られた粉末を乳鉢で粉砕し、正極活物質Ａを得た。 Next, Na 4 Fe (CN) 6 · 10H 2 O was dissolved in ion-exchanged water, dropped into the above mixed solution, and stirred at 90 ° C. for 6 hours. Thereafter, the mixture was filtered, and the residue was washed with ion exchange water and then with acetone. Subsequently, the liquid was dried at 120 ° C. for 48 hours, and the obtained powder was pulverized in a mortar to obtain a positive electrode active material A.
　〔正極の作製〕
　まず、ＰＶＤＦ（PolyVinylidene DiFluoride）をＮＭＰ（N-methyl pyrrolidone）中に溶解してＮＭＰ溶液を得た。次いで、このＮＭＰ溶液に、カーボンブラックＢと前述の正極活物質作製工程にて得られた正極活物質Ａとを注いで混合した。混合比率は、Ａ：Ｂ：ＰＶＤＦ＝７５：１５：１０ｗｔ％とした。 [Production of positive electrode]
First, PVDF (PolyVinylidene DiFluoride) was dissolved in NMP (N-methyl pyrrolidone) to obtain an NMP solution. Next, carbon black B and the positive electrode active material A obtained in the above-described positive electrode active material preparation step were poured into and mixed with this NMP solution. The mixing ratio was A: B: PVDF = 75: 15: 10 wt%.
　さらに、薄膜旋回型高速ミキサー（商品名：フィルミックス（登録商標）４０－４０型（プライミクス株式会社製））を用いて室温下で攪拌混合して電極ペーストを得た。この電極ペーストを、厚さ２０μｍの圧延アルミニウム箔上に片面に塗布した後、空気中において１００℃で３０分間乾燥した。 Further, an electrode paste was obtained by stirring and mixing at room temperature using a thin film swirl type high speed mixer (trade name: Filmix (registered trademark) 40-40 type (manufactured by Primics Co., Ltd.)). The electrode paste was applied on one side of a rolled aluminum foil having a thickness of 20 μm, and then dried in air at 100 ° C. for 30 minutes.
　次いで、プレス加工することにより、正極１１として実施例の正極板（塗工面サイズ：２８ｍｍ（縦）×２８ｍｍ（横））を得た。 Next, the positive electrode plate of Example (coated surface size: 28 mm (vertical) × 28 mm (horizontal)) was obtained as the positive electrode 11 by pressing.
　その際、プレス（サンクメタル製１トン小型精密ロールプレス）機のギャップを調整することにより、電極の厚みと重量とから算出した電極密度が１．１ｇ／ｃｍ３となるようにした。 At that time, the electrode density calculated from the thickness and weight of the electrode was adjusted to 1.1 g / cm 3 by adjusting the gap of a press (Thunk Metal 1-ton small precision roll press).
　〔負極の作製〕
　正極１１と同様に、ＰＶＤＦ（PolyVinylidene DiFluoride）をＮＭＰ（N-methyl pyrrolidone）中に溶解してＮＭＰ溶液を得た。次いで、このＮＭＰ溶液に、ハードカーボンＣを注いで混合した。混合比率は、Ｃ：ＰＶＤＦ＝９５：５ｗｔ％とした。 (Production of negative electrode)
Similarly to the positive electrode 11, PVDF (PolyVinylidene DiFluoride) was dissolved in NMP (N-methylpyrrolidone) to obtain an NMP solution. Next, hard carbon C was poured into the NMP solution and mixed. The mixing ratio was C: PVDF = 95: 5 wt%.
　さらに、２軸遊星プラネタリミキサー（プライミクス株式会社製）を用いて、室温下で攪拌混練して電極ペーストを得た。この電極ペーストを、厚さ：２０μｍの圧延アルミニウム箔上に片面に塗布した後、空気中において１００℃で３０分間乾燥した。 Further, an electrode paste was obtained by stirring and kneading at room temperature using a biaxial planetary mixer (manufactured by Primex Corporation). This electrode paste was applied to one side of a rolled aluminum foil having a thickness of 20 μm, and then dried in air at 100 ° C. for 30 minutes.
　次いで、プレス加工して負極１２として実施例の負極板（塗工面サイズ：３０ｍｍ（縦）×３０ｍｍ（横））を得た。 Next, press working was performed to obtain a negative electrode plate (coating surface size: 30 mm (vertical) × 30 mm (horizontal)) as the negative electrode 12.
　その際、プレス機（サンクメタル製１トン小型精密ロールプレス）のギャップを調整することにより、電極の厚みを変化させ、厚みと重量とから算出した電極密度が、０．９、１．０、１．１、１．２、１．３ｇ／ｃｍ３の電極を得た。 At that time, the thickness of the electrode was changed by adjusting the gap of the press machine (Thunk Metal 1-ton small precision roll press), and the electrode density calculated from the thickness and weight was 0.9, 1.0, Electrodes of 1.1, 1.2 and 1.3 g / cm 3 were obtained.
　〔電池の作製〕
　前述の正極作製工程及び負極作製工程により作製した正極１１及び負極１２を、１３０℃で２４時間減圧乾燥した。その後、ドライＡｒ雰囲気下のグローボックス内に上記正極及び負極を入れた後、該正極１１及び負極１２のそれぞれに接着フィルム１６・１６の付いた正極側アルミニウム製タブリード１４及び負極側アルミニウム製タブリード１５を超音波溶接した。 [Production of battery]
The positive electrode 11 and the negative electrode 12 produced by the positive electrode production process and the negative electrode production process described above were dried under reduced pressure at 130 ° C. for 24 hours. Thereafter, after the positive electrode and the negative electrode are placed in a glow box in a dry Ar atmosphere, the positive electrode-side aluminum tab lead 14 and the negative electrode-side aluminum tab lead 15 with adhesive films 16 and 16 attached to the positive electrode 11 and the negative electrode 12, respectively. Were ultrasonically welded.
　次いで、グローボックス内で、負極１２の塗工面１２ａが隠れるようにセパレータ１３としてポリオレフィンの微多孔膜（セルガード株式会社製、サイズ：３０ｍｍ（縦）×３０ｃｍ（横）、厚さ２５μｍ）を積載し、塗工面が中心に重なるように正極１１を重ね単セル１０を作製した。 Next, in the glow box, a polyolefin microporous film (manufactured by Celgard, size: 30 mm (length) × 30 cm (width), thickness 25 μm) is loaded as a separator 13 so that the coated surface 12a of the negative electrode 12 is hidden. A single cell 10 was fabricated by stacking the positive electrode 11 so that the coated surface overlapped with the center.
　さらに、アルミラミネートフィルム２・３にて単セル１０を挟み、正極側アルミニウム製タブリード１４及び負極側アルミニウム製タブリード１５の接着フィルム１６・１６を挟むようにアルミラミネートフィルム２・３の各３辺における熱圧着部２ａ・３ａを熱溶着した。この段階では、アルミラミネートフィルム２・３は、袋状となっている。 Further, the single cell 10 is sandwiched between the aluminum laminate films 2 and 3, and the adhesive films 16 and 16 of the positive electrode side aluminum tab lead 14 and the negative electrode side aluminum tab lead 15 are sandwiched between the three sides of the aluminum laminate films 2 and 3. The thermocompression bonding parts 2a and 3a were thermally welded. At this stage, the aluminum laminate films 2 and 3 are in a bag shape.
　次いで、アルミラミネートフィルム２・３の未溶着の１辺から、エチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）とを体積比１：２にて混合した溶媒に、１ｍｏｌ／ｌになるようにＮａＰＦ６を溶解させた電解液を単セル１０へ注液し、アルミラミネートフィルム２・３の最後の１辺を１０ｋＰａの減圧下で熱融着してナトリウムイオン電池１を得た。 Next, from one side of the aluminum laminate films 2 and 3 which are not welded, NaPF 6 is added to a solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed at a volume ratio of 1: 2 so as to be 1 mol / l. The sodium ion battery 1 was obtained by injecting the electrolyte solution in which the solution was dissolved into the single cell 10 and thermally fusing the last side of the aluminum laminate films 2 and 3 under a reduced pressure of 10 kPa.
　電解液の注液量は、ナトリウムイオン電池１の正極１１、負極１２及びセパレータ１３に電解液が十分浸透する量とした。 The amount of electrolyte solution injected was such that the electrolyte solution sufficiently penetrated into the positive electrode 11, the negative electrode 12 and the separator 13 of the sodium ion battery 1.
　ここで、作製した単セル１０の正極１１及び負極１２を各実施例及び比較例における目付量、層厚、電極密度としたときのセル平均放電電圧について、図３及び図１に示す。図３は、作製した単セル１０の各実施例及び比較例における正極１１及び負極１２の目付量、層厚、電極密度、及び放電平均電圧を示す図である。図１は、各実施例及び比較例における負極活物質層密度とセル平均放電電圧との関係をプロットしたグラフである。 Here, FIG. 3 and FIG. 1 show the cell average discharge voltage when the positive electrode 11 and the negative electrode 12 of the produced single cell 10 are the basis weight, the layer thickness, and the electrode density in each example and comparative example. FIG. 3 is a diagram showing the basis weight, the layer thickness, the electrode density, and the discharge average voltage of the positive electrode 11 and the negative electrode 12 in each example and comparative example of the produced single cell 10. FIG. 1 is a graph plotting the relationship between the negative electrode active material layer density and the cell average discharge voltage in each Example and Comparative Example.
　尚、図１及び図３に示す単セル１０の平均放電電圧は、作製したナトリウムイオン電池１を２５℃で０．１Ｃ充電し、かつ放電レート１０Ｃにて放電して測定した値である。この場合、正極１１の充放電における電理論容量から算出される容量を１ｈにて充電又は放電する電流を１Ｃとしている。 In addition, the average discharge voltage of the single cell 10 shown in FIG.1 and FIG.3 is the value measured by charging 0.1-C of the produced sodium ion battery 1 at 25 degreeC, and discharging at the discharge rate 10C. In this case, the current calculated from the theoretical capacity in charge / discharge of the positive electrode 11 is charged or discharged in 1 h is 1 C.
　正極１１の電極密度を１．１ｇ／ｃｍ３とした場合の１０Ｃにおける単セル１０の平均放電電圧の結果は、図１及び図３に示すように、正極１１の目付量を６．７ｍｇ／ｃｍ２とし、かつ負極１２の目付量を４ｍｇ／ｃｍ２とした場合には、セル平均放電電圧は、負極活物質層密度０．９ｇ／ｃｍ３である比較例１では２．５１（Ｖ）であったのに対して、負極活物質層密度１ｇ／ｃｍ３である実施例１では２．６８（Ｖ）であり、負極活物質層密度１．１ｇ／ｃｍ３である実施例２では２．８４（Ｖ）であり、負極活物質層密度１．２ｇ／ｃｍ３である実施例３では２．９１（Ｖ）であり、負極活物質層密度１．３ｇ／ｃｍ３である実施例４では２．８９（Ｖ）であった。この結果、負極活物質層の密度を０．９５～１．３５ｇ／ｃｍ３とした実施例１～実施例４においては、比較例１に比べて高出力のナトリウムイオン電池１が得られることが確認できた。 As a result of the average discharge voltage of the single cell 10 at 10 C when the electrode density of the positive electrode 11 is 1.1 g / cm 3 , the basis weight of the positive electrode 11 is 6.7 mg / cm as shown in FIGS. 2 and the basis weight of the negative electrode 12 is 4 mg / cm 2 , the cell average discharge voltage is 2.51 (V) in Comparative Example 1 where the negative electrode active material layer density is 0.9 g / cm 3. On the other hand, in Example 1 where the negative electrode active material layer density was 1 g / cm 3 , it was 2.68 (V), and in Example 2 where the negative electrode active material layer density was 1.1 g / cm 3, it was 2.2. In Example 3, which is 84 (V), the negative electrode active material layer density is 1.2 g / cm 3, it is 2.91 (V), and in Example 4 where the negative electrode active material layer density is 1.3 g / cm 3 , It was 2.89 (V). As a result, in Examples 1 to 4 in which the density of the negative electrode active material layer was 0.95 to 1.35 g / cm 3 , it was possible to obtain a higher-power sodium ion battery 1 compared to Comparative Example 1. It could be confirmed.
　また、正極１１の電極密度を１．１ｇ／ｃｍ３とした場合において、正極１１の目付量を１０ｍｇ／ｃｍ２とし、かつ負極１２の目付量を６ｍｇ／ｃｍ２とした場合には、セル平均放電電圧は、負極活物質層密度０．９ｇ／ｃｍ３である比較例２では２．４（Ｖ）であったのに対して、負極活物質層密度１ｇ／ｃｍ３である実施例５では２．５７（Ｖ）であり、負極活物質層密度１．１ｇ／ｃｍ３である実施例６では２．７（Ｖ）であり、負極活物質層密度１．２ｇ／ｃｍ３である実施例７では２．７４（Ｖ）であり、負極活物質層密度１．３ｇ／ｃｍ３である実施例８では２．７１（Ｖ）であった。この結果、負極活物質層の密度を０．９５～１．３５ｇ／ｃｍ３とした実施例５～実施例８においては、比較例２に比べて高出力のナトリウムイオン電池１が得られることが確認できた。 Further, in the case where the electrode density of the positive electrode 11 is 1.1 g / cm 3 , when the basis weight of the positive electrode 11 is 10 mg / cm 2 and the basis weight of the negative electrode 12 is 6 mg / cm 2 , the cell average The discharge voltage was 2.4 (V) in Comparative Example 2 where the negative electrode active material layer density was 0.9 g / cm 3 , while in Example 5 where the negative electrode active material layer density was 1 g / cm 3. In Example 6, which is 2.57 (V) and the negative electrode active material layer density is 1.1 g / cm 3, it is 2.7 (V) and the negative electrode active material layer density is 1.2 g / cm 3. 7 was 2.74 (V), and in Example 8 where the negative electrode active material layer density was 1.3 g / cm 3 , it was 2.71 (V). As a result, in Examples 5 to 8 in which the density of the negative electrode active material layer was 0.95 to 1.35 g / cm 3 , it was possible to obtain a higher-power sodium ion battery 1 compared to Comparative Example 2. It could be confirmed.
　さらに、正極１１の正極活物質層の密度を１．１ｇ／ｃｍ３とした場合において、正極１１の目付量を１３．３ｍｇ／ｃｍ２とし、かつ負極１２の目付量を８ｍｇ／ｃｍ２とした場合には、セル平均放電電圧は、負極活物質層密度０．９ｇ／ｃｍ３である比較例３では２．２５（Ｖ）であったのに対して、負極活物質層密度１ｇ／ｃｍ３である実施例９では２．３５（Ｖ）であり、負極活物質層密度１．１ｇ／ｃｍ３である実施例１０では２．４３（Ｖ）であり、負極活物質層密度１．２ｇ／ｃｍ３である実施例１１では２．４３（Ｖ）であり、負極活物質層密度１．３ｇ／ｃｍ３である実施例１２では２．３２（Ｖ）であった。この結果、負極活物質層の密度を０．９５～１．３５ｇ／ｃｍ３とした実施例９～実施例１２においては、比較例３に比べて高出力のナトリウムイオン電池１が得られることが確認できた。 Further, in the case where the density of the positive electrode active material layer of the positive electrode 11 was set to 1.1 g / cm 3, the basis weight of the positive electrode 11 and 13.3 mg / cm 2, and the basis weight of the negative electrode 12 was set to 8 mg / cm 2 In this case, the cell average discharge voltage was 2.25 (V) in Comparative Example 3 having a negative electrode active material layer density of 0.9 g / cm 3 , whereas the negative electrode active material layer density was 1 g / cm 3. In Example 9, which is 2.35 (V), and in Example 10, where the negative electrode active material layer density is 1.1 g / cm 3, it is 2.43 (V), and the negative electrode active material layer density is 1.2 g / cm 3. In Example 11 which is cm 3 , it was 2.43 (V), and in Example 12 where the negative electrode active material layer density was 1.3 g / cm 3 , it was 2.32 (V). As a result, in Examples 9 to 12 in which the density of the negative electrode active material layer was 0.95 to 1.35 g / cm 3 , it was possible to obtain a higher-power sodium ion battery 1 compared to Comparative Example 3. It could be confirmed.
　これらの結果から、総合して、負極活物質層の密度を０．９５～１．３５ｇ／ｃｍ３、より好ましくは１．１～１．３ｇ／ｃｍ３とすることにより、高出力のナトリウムイオン電池１が得られることが確認できた。 From these results, the high density sodium ion can be obtained by setting the density of the negative electrode active material layer to 0.95 to 1.35 g / cm 3 , more preferably 1.1 to 1.3 g / cm 3. It was confirmed that the battery 1 was obtained.
　また、上記の結果から、負極活物質層の目付量が、７ｍｇ／ｃｍ２以下であることが好ましいことが確認できた。 Moreover, from the above results, it was confirmed that the basis weight of the negative electrode active material layer was preferably 7 mg / cm 2 or less.
　このように、本実施の形態のナトリウムイオン電池１は、ナトリウムイオンの挿入及び脱離が可能な正極活物質を含む正極１１と、ナトリウムイオンの挿入及び脱離が可能な難黒鉛化炭素を含む負極活物質層を有する負極１２と、ナトリウムイオン導電性を有する電解質を含む。そして、負極活物質層の密度は０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下である。 As described above, the sodium ion battery 1 of the present embodiment includes the positive electrode 11 including the positive electrode active material capable of inserting and desorbing sodium ions, and the non-graphitizable carbon capable of inserting and desorbing sodium ions. A negative electrode 12 having a negative electrode active material layer and an electrolyte having sodium ion conductivity are included. The density of the negative electrode active material layer is 0.95 g / cm 3 or more and 1.35 g / cm 3 or less.
　すなわち、従来の難黒鉛化炭素を含む負極活物質層では、密度が例えば０．９ｇ／ｃｍ３程度であり、高出力時に分極が大きいという課題があった。しかし、本実施の形態では、負極活物質層の密度を０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下であるとすることによって、従来よりも高出力特性を図り得るナトリウムイオン電池１を提供することができる。 That is, the conventional negative electrode active material layer containing non-graphitizable carbon has a problem that the density is, for example, about 0.9 g / cm 3 and the polarization is large at high output. However, in the present embodiment, by setting the density of the negative electrode active material layer to 0.95 g / cm 3 or more and 1.35 g / cm 3 or less, the sodium ion battery 1 that can achieve higher output characteristics than conventional ones. Can be provided.
　また、本実施の形態におけるナトリウムイオン電池１は、正極１１中のナトリウムイオンの挿入及び脱離が可能な正極活物質が、ＮａｍＭ１ｘＭ２ｙ（ＣＮ）６・ｚＨ２Ｏにて表わされ、Ｍ１及びＭ２は遷移金属であり、
　０＜ｍ≦２、０．５≦ｘ≦１．５、０．５≦ｙ≦１．５、０＜ｚ≦１０
である。 Further, in the sodium ion battery 1 according to the present embodiment, the positive electrode active material capable of inserting and removing sodium ions in the positive electrode 11 is represented by Na m M1 x M2 y (CN) 6 · zH 2 O. M1 and M2 are transition metals,
0 <m ≦ 2, 0.5 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.5, 0 <z ≦ 10
It is.
　これにより、本実施の形態では、正極活物質は金属複合酸化物とは異なる成分にて構成されているので、正極活物質が金属複合酸化物ある場合に比べて高出力特性を期待することができる。 Thereby, in this Embodiment, since a positive electrode active material is comprised by the component different from a metal complex oxide, compared with the case where a positive electrode active material is a metal complex oxide, it can expect a high output characteristic. it can.
　また、本実施の形態におけるナトリウムイオン電池１は、正極活物質の遷移金属Ｍ１は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種であると共に、前記正極活物質の遷移金属Ｍ２は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種である。 In the sodium ion battery 1 according to the present embodiment, the transition metal M1 of the positive electrode active material is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg. The transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg. .
　これにより、遷移金属Ｍ１及び遷移金属Ｍ２として、高出力特性を期待することができる材料の組み合わせを選択することができる。 Thereby, a combination of materials that can be expected to have high output characteristics can be selected as the transition metal M1 and the transition metal M2.
　また、本実施の形態におけるナトリウムイオン電池１は、正極活物質の遷移金属Ｍ１は、Ｍｎ又はＦｅであり、正極活物質の遷移金属Ｍ２は、Ｆｅであるとすることができる。 Further, in the sodium ion battery 1 in the present embodiment, the transition metal M1 of the positive electrode active material can be Mn or Fe, and the transition metal M2 of the positive electrode active material can be Fe.
　これによっても、遷移金属Ｍ１及び遷移金属Ｍ２として、高出力特性を期待することができる材料の組み合わせを選択することができる。 Also by this, it is possible to select a combination of materials that can be expected to have high output characteristics as the transition metal M1 and the transition metal M2.
　また、本実施の形態におけるナトリウムイオン電池１は、負極活物質層の目付量が、７ｍｇ／ｃｍ２以下である。これにより、負極活物質層の目付量が、７ｍｇ／ｃｍ２を超える場合に比べて、高出力特性を期待することができる。 Moreover, in the sodium ion battery 1 in the present embodiment, the basis weight of the negative electrode active material layer is 7 mg / cm 2 or less. Thereby, compared with the case where the areal weight of a negative electrode active material layer exceeds 7 mg / cm < 2 >, a high output characteristic can be anticipated.
　〔まとめ〕
　本発明の態様１におけるナトリウムイオン電池１は、ナトリウムイオンの挿入及び脱離が可能な正極活物質を含む正極１１と、ナトリウムイオンの挿入及び脱離が可能な難黒鉛化炭素を含む負極活物質層を有する負極１２と、ナトリウムイオン導電性を有する電解質を含むナトリウムイオン電池であって、前記負極活物質層の密度が０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下であることを特徴としている。 [Summary]
A sodium ion battery 1 according to aspect 1 of the present invention includes a positive electrode 11 including a positive electrode active material capable of inserting and desorbing sodium ions, and a negative electrode active material including non-graphitizable carbon capable of inserting and desorbing sodium ions. A sodium ion battery including a negative electrode 12 having a layer and an electrolyte having sodium ion conductivity, wherein the density of the negative electrode active material layer is 0.95 g / cm 3 or more and 1.35 g / cm 3 or less. It is a feature.
　上記の発明によれば、前記負極活物質層の密度が０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下となっている。このため、従来の難黒鉛化炭素を含む負極活物質層では、密度が例えば０．９ｇ／ｃｍ３程度であり、高出力時に分極が大きいという課題があったが、本発明では、負極活物質層の密度が０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下であるとすることによって、従来よりも高出力特性を図り得るナトリウムイオン電池を提供することができる。 According to said invention, the density of the said negative electrode active material layer is 0.95 g / cm < 3 > or more and 1.35 g / cm < 3 > or less. For this reason, the conventional negative electrode active material layer containing non-graphitizable carbon has a problem that the density is, for example, about 0.9 g / cm 3 and the polarization is large at high output. By setting the density of the layer to be 0.95 g / cm 3 or more and 1.35 g / cm 3 or less, a sodium ion battery capable of achieving higher output characteristics than the conventional one can be provided.
　本発明の態様２におけるナトリウムイオン電池１は、態様１におけるナトリウムイオン電池において、前記正極１１中のナトリウムイオンの挿入及び脱離が可能な正極活物質が、ＮａｍＭ１ｘＭ２ｙ（ＣＮ）６・ｚＨ２Ｏにて表わされ、Ｍ１及びＭ２は遷移金属であり、
　０＜ｍ≦２、０．５≦ｘ≦１．５、０．５≦ｙ≦１．５、０＜ｚ≦１０
であることが好ましい。 The sodium ion battery 1 according to aspect 2 of the present invention is the sodium ion battery according to aspect 1, wherein the positive electrode active material capable of inserting and desorbing sodium ions in the positive electrode 11 is Na m M1 x M2 y (CN) 6. Represented by zH 2 O, M1 and M2 are transition metals,
0 <m ≦ 2, 0.5 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.5, 0 <z ≦ 10
It is preferable that
　これにより、正極活物質がＮａｍＭ１ｘＭ２ｙ（ＣＮ）６・Ｈ２Ｏにて表わされるものとなっている。このため、正極活物質は、金属複合酸化物とは異なる成分にて構成されているので、正極活物質が金属複合酸化物ある場合に比べて高出力特性を期待することができる。 Thus, it has become a cathode active material is represented by Na m M1 x M2 y (CN ) 6 · H 2 O. For this reason, since the positive electrode active material is composed of a component different from the metal composite oxide, higher output characteristics can be expected as compared with the case where the positive electrode active material is a metal composite oxide.
　本発明の態様３におけるナトリウムイオン電池１は、態様２におけるナトリウムイオン電池において、前記正極活物質の遷移金属Ｍ１は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種であると共に、前記正極活物質の遷移金属Ｍ２は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種であるとすることができる。 The sodium ion battery 1 according to aspect 3 of the present invention is the sodium ion battery according to aspect 2, wherein the transition metal M1 of the positive electrode active material is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, The transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Mg, and is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, Mg. It may be at least one selected.
　これにより、遷移金属Ｍ１及び遷移金属Ｍ２として、高出力特性を期待することができる材料の組み合わせを選択することができる。尚、遷移金属Ｍ１：Ｔｉ、遷移金属Ｍ２：Ｔｉとの同種金属の組み合わせでもよい。 Thereby, a combination of materials that can be expected to have high output characteristics can be selected as the transition metal M1 and the transition metal M2. In addition, the combination of the same kind metal with transition metal M1: Ti and transition metal M2: Ti may be sufficient.
　本発明の態様４におけるナトリウムイオン電池１は、態様２におけるナトリウムイオン電池において、前記正極活物質の遷移金属Ｍ１は、Ｍｎ又はＦｅであり、前記正極活物質の遷移金属Ｍ２は、Ｆｅであるとすることができる。 A sodium ion battery 1 according to Aspect 4 of the present invention is the sodium ion battery according to Aspect 2, wherein the transition metal M1 of the positive electrode active material is Mn or Fe, and the transition metal M2 of the positive electrode active material is Fe. can do.
　これにより、遷移金属Ｍ１及び遷移金属Ｍ２として、高出力特性を期待することができる材料の組み合わせを選択することができる。尚、遷移金属Ｍ１：Ｆｅ、遷移金属Ｍ２：Ｆｅとの同種金属の組み合わせでもよい。 Thereby, a combination of materials that can be expected to have high output characteristics can be selected as the transition metal M1 and the transition metal M2. A combination of the same metals as transition metal M1: Fe and transition metal M2: Fe may be used.
　本発明の態様５におけるナトリウムイオン電池１は、態様２～４のいずれか１のナトリウムイオン電池において、前記負極活物質層の目付量が、７ｍｇ／ｃｍ２以下であることが好ましい。 In the sodium ion battery 1 according to the fifth aspect of the present invention, the basis weight of the negative electrode active material layer is preferably 7 mg / cm 2 or less in the sodium ion battery according to any one of the second to fourth aspects.
　これにより、負極活物質層の目付量が、７ｍｇ／ｃｍ２を超える場合に比べて、高出力特性を期待することができる。 Thereby, compared with the case where the areal weight of a negative electrode active material layer exceeds 7 mg / cm < 2 >, a high output characteristic can be anticipated.
　尚、本発明は、上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.
　本発明は、ナトリウムイオンの挿入及び脱離が可能な正極活物質を含む正極と、ナトリウムイオンの挿入及び脱離が可能な難黒鉛化炭素を含む負極活物質層を有する負極と、ナトリウムイオン導電性を有する電解質を含むナトリウムイオン電池に適用できる。 The present invention relates to a positive electrode including a positive electrode active material capable of inserting and desorbing sodium ions, a negative electrode having a negative electrode active material layer including non-graphitizable carbon capable of inserting and desorbing sodium ions, and sodium ion conductivity. The present invention can be applied to a sodium ion battery including an electrolyte having a property.
　１　　　　　ナトリウムイオン電池
　２・３　　　アルミラミネートフィルム
　２ａ・３ａ　熱圧着部
１０　　　　　単セル
１１　　　　　正極
１２　　　　　負極
１２ａ　　　　塗工面
１３　　　　　セパレータ
１４　　　　　正極側アルミニウム製タブリード
１５　　　　　負極側アルミニウム製タブリード
１６　　　　　接着フィルム DESCRIPTION OF SYMBOLS 1 Sodium ion battery 2.3 Aluminum laminated film 2a-3a Thermocompression bonding part 10 Single cell 11 Positive electrode 12 Negative electrode 12a Coating surface 13 Separator 14 Positive electrode side aluminum tab lead 15 Negative electrode side aluminum tab lead 16 Adhesive film

Claims (5)

  1. 　ナトリウムイオンの挿入及び脱離が可能な正極活物質を含む正極と、ナトリウムイオンの挿入及び脱離が可能な難黒鉛化炭素を含む負極活物質層を有する負極と、ナトリウムイオン導電性を有する電解質を含むナトリウムイオン電池であって、
    　前記負極活物質層の密度が０．９５ｇ／ｃｍ３以上かつ１．３５ｇ／ｃｍ３以下であることを特徴とするナトリウムイオン電池。     A positive electrode including a positive electrode active material capable of inserting and desorbing sodium ions, a negative electrode including a negative electrode active material layer including non-graphitizable carbon capable of inserting and desorbing sodium ions, and an electrolyte having sodium ion conductivity A sodium ion battery comprising:
    The density of the said negative electrode active material layer is 0.95 g / cm < 3 > or more and 1.35 g / cm < 3 > or less, The sodium ion battery characterized by the above-mentioned.
  2. 　前記正極中のナトリウムイオンの挿入及び脱離が可能な正極活物質が、ＮａｍＭ１ｘＭ２ｙ（ＣＮ）６・ｚＨ２Ｏにて表わされ、Ｍ１及びＭ２は遷移金属であり、
    　０＜ｍ≦２、０．５≦ｘ≦１．５、０．５≦ｙ≦１．５、０＜ｚ≦１０
    であることを特徴とする請求項１記載のナトリウムイオン電池。     A positive electrode active material capable of inserting and desorbing sodium ions in the positive electrode is represented by Na m M1 x M2 y (CN) 6 · zH 2 O, and M1 and M2 are transition metals,
    0 <m ≦ 2, 0.5 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.5, 0 <z ≦ 10
    The sodium ion battery according to claim 1, wherein:
  3. 　前記正極活物質の遷移金属Ｍ１は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種であると共に、
    　前記正極活物質の遷移金属Ｍ２は、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃａ，Ｍｇからなる群から選択される少なくとも１種であることを特徴とする請求項２記載のナトリウムイオン電池。     The transition metal M1 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, Mg,
    The transition metal M2 of the positive electrode active material is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ca, and Mg. 2. The sodium ion battery according to 2.
  4. 　前記正極活物質の遷移金属Ｍ１は、Ｍｎ又はＦｅであり、
    　前記正極活物質の遷移金属Ｍ２は、Ｆｅであることを特徴とする請求項２記載のナトリウムイオン電池。     The transition metal M1 of the positive electrode active material is Mn or Fe,
    The sodium ion battery according to claim 2, wherein the transition metal M2 of the positive electrode active material is Fe.
  5. 　前記負極活物質層の目付量が、７ｍｇ／ｃｍ２以下であることを特徴とする請求項２～４のいずれか１項に記載のナトリウムイオン電池。 The sodium ion battery according to any one of claims 2 to 4, wherein a weight per unit area of the negative electrode active material layer is 7 mg / cm 2 or less.
PCT/JP2016/050916 2015-03-30 2016-01-14 Sodium-ion cell WO2016157934A1 (en)

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JP2007134244A (en) * 2005-11-11 2007-05-31 Sony Corp Battery
WO2012028858A1 (en) * 2010-09-03 2012-03-08 Nexeon Limited Electroactive material
JP2012169160A (en) * 2011-02-15 2012-09-06 Sumitomo Chemical Co Ltd Electrode for sodium secondary battery and sodium secondary battery
JP2013152869A (en) * 2012-01-25 2013-08-08 Univ Of Tsukuba Sodium battery and cathode member for the same
WO2013157660A1 (en) * 2012-04-17 2013-10-24 Sharp Kabushiki Kaisha Alkali and alkaline-earth ion batteries with hexacyanometallate cathode and non-metal anode
JP2014053181A (en) * 2012-09-07 2014-03-20 Ngk Insulators Ltd All-solid battery

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007134244A (en) * 2005-11-11 2007-05-31 Sony Corp Battery
WO2012028858A1 (en) * 2010-09-03 2012-03-08 Nexeon Limited Electroactive material
JP2012169160A (en) * 2011-02-15 2012-09-06 Sumitomo Chemical Co Ltd Electrode for sodium secondary battery and sodium secondary battery
JP2013152869A (en) * 2012-01-25 2013-08-08 Univ Of Tsukuba Sodium battery and cathode member for the same
WO2013157660A1 (en) * 2012-04-17 2013-10-24 Sharp Kabushiki Kaisha Alkali and alkaline-earth ion batteries with hexacyanometallate cathode and non-metal anode
JP2014053181A (en) * 2012-09-07 2014-03-20 Ngk Insulators Ltd All-solid battery

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