JP2009064584A - Nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery with a large capacity and a high output. <P>SOLUTION: The nonaqueous electrolyte battery 10 is provided with a negative electrode 14 made of lithium metal foil and a positive electrode 16 arranged to face with each other with a nonaqueous electrolyte 18 in-between. The positive electrode 16 is manufactured in a process in which a conductive material 16b and a binder 16c are mixed and the same is press-formed together with a nickel mesh 16a of a current collector. Moreover, the nonaqueous electrolyte 18 contains halogen such as iodine or the like in addition to lithium salt such as lithium hexa-fluoro-phosphate or the like. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte battery.

  In recent years, the market for portable information devices such as mobile phones and e-mail terminals is rapidly expanding. In addition, expectations for hybrid vehicles and electric vehicles are increasing from the viewpoint of environmental problems and the energy crisis. In light of this background, there is a need for high-energy storage devices.

  The standard reduction potential of lithium is -3.05 V, which is the most base metal in the electrochemical series. That is, the operating voltage of an electricity storage device using this as a negative electrode is high and becomes high energy. On the other hand, since the atomic weight of lithium is the smallest among metals, its theoretical capacity is very large at 3862 mAh / g. Therefore, when lithium is used for the negative electrode, an energy storage device with high energy density is possible.

  On the other hand, a metal-air battery using a metal as a negative electrode active material and oxygen in the atmosphere as a positive electrode active material is known. Since the metal-air battery is supplied with oxygen from the outside, it becomes a high-capacity electricity storage device. The above-described metal-air battery in which lithium is combined is called a lithium-air battery, and has recently been attracting attention as a high energy storage device (see, for example, Patent Documents 1, 2, and 3). In such a lithium-air battery, an electrochemical reaction of oxygen occurs at the positive electrode, lithium peroxide and lithium oxide are generated during discharge, and these oxides are decomposed during charging to generate oxygen gas.

On the other hand, as a metal halogen battery, a zinc bromine battery (for example, Patent Document 4) using zinc as a negative electrode and bromine as a positive electrode has been known for a long time.
JP2003-7357 JP-A-2005-166585 JP 2006-286414 A JP-A-4-223049

  However, a lithium-air battery is expected to have a high capacity, but it is difficult to obtain a high output. Moreover, since the zinc bromine battery is water-based and cannot normally take a potential higher than the electrolysis voltage of water, it has been difficult to increase the capacity.

  The present invention has been made in view of the above-described problems, and has as its main object to provide a high-capacity and high-power nonaqueous electrolyte battery.

  In order to achieve the above-mentioned object, the present inventors manufactured a battery in which a carbon positive electrode and a negative electrode made of metallic lithium are arranged via a non-aqueous electrolyte containing lithium ions and iodine, When a battery in which a carbon positive electrode containing lithium iodide and a negative electrode made of metallic lithium are arranged via a non-aqueous electrolyte containing the lithium battery is produced, both batteries can realize a high-capacity and high-output energy storage device. As a result, the present invention has been completed.

  That is, in the first nonaqueous electrolyte battery of the present invention, a negative electrode using a material that absorbs and releases lithium ions as a negative electrode active material and a positive electrode using halogen as a positive electrode active material are arranged via a nonaqueous electrolyte containing lithium ions. The non-aqueous electrolyte battery includes at least one halogen selected from the group consisting of iodine, bromine and chlorine.

  In the second nonaqueous electrolyte battery of the present invention, a negative electrode using a material that absorbs and releases lithium ions as a negative electrode active material and a positive electrode using halogen as a positive electrode active material are arranged via a nonaqueous electrolyte containing lithium ions. In the nonaqueous electrolyte battery, the positive electrode includes at least one lithium halide selected from the group consisting of lithium iodide, lithium bromide, and lithium chloride.

Such charge / discharge reactions of the first and second nonaqueous electrolyte batteries of the present invention proceed as follows when, for example, metallic lithium is used as the negative electrode active material and iodine is used as the positive electrode active material.

  According to the first and second non-aqueous electrolyte batteries of the present invention, at least one halogen selected from the group consisting of iodine, bromine and chlorine having excellent electrolyte solubility is used instead of oxygen in the conventional lithium-air battery. Since it is used, it is possible to charge and discharge with a large current while maintaining a high capacity. The reason why such an effect is obtained is not clear, but by using iodine or the like having higher solubility in non-aqueous electrolyte than oxygen, the function as a positive electrode active material is improved, and high capacity and high output are realized. Presumed.

  First, the first nonaqueous electrolyte battery of the present invention will be described.

  In the first nonaqueous electrolyte battery of the present invention, the negative electrode contains a material that absorbs and releases lithium ions as a negative electrode active material. Here, examples of materials that occlude and release lithium ions include metal lithium and lithium alloys, metal oxides, metal sulfides, and carbonaceous substances that occlude and release lithium ions. Examples of the lithium alloy include alloys of lithium with aluminum, silicon, tin, magnesium, indium, calcium, and the like. Examples of the metal oxide include tin oxide, silicon oxide, lithium titanium oxide, niobium oxide, and tungsten oxide. Examples of the metal sulfide include tin sulfide and titanium sulfide. Examples of the carbonaceous material that absorbs and releases lithium ions include graphite, coke, mesophase pitch-based carbon fiber, spherical carbon, and resin-fired carbon.

In the first nonaqueous electrolyte battery of the present invention, the positive electrode uses at least one halogen selected from the group consisting of iodine (I ₂ ), bromine (Br ₂ ), and chlorine (Cl ₂ ) as the positive electrode active material. These positive electrode active materials are supplied by halogen dissolved in an electrolyte described later. The positive electrode may be formed by mixing a predetermined amount of a conductive material and a binder and then press-molding the current collector. At this time, the mixing ratio of the conductive material and the binder is not particularly limited. For example, the binder may be 3 to 10 parts by weight with respect to 100 parts by weight of the conductive material. As a mixing method, wet mixing may be performed together with carbon powder or a binder in a solvent such as N-methylpyrrolidone, or dry mixing may be performed using a mortar or the like. Here, the conductive material is not particularly limited as long as it is a conductive material. For example, carbon blacks such as ketjen black, acetylene black, channel black, furnace black, lamp black and thermal black may be used, and natural graphite such as flake graphite, graphite such as artificial graphite and expanded graphite may be used. Further, conductive fibers such as carbon fibers and metal fibers, metal powders such as copper, silver, nickel, and aluminum, or organic conductive materials such as polyphenylene derivatives may be used. These may be used alone or in combination. Although it does not specifically limit as a binder, A thermoplastic resin, a thermosetting resin, etc. are mentioned. For example, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin) , Polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrif Examples include olefin copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, and ethylene-acrylic acid copolymer. . These materials may be used alone or in combination. As the current collector, is not particularly limited, for example, InSnO _2, SnO _2, ZnO, transparent conductive material such as an In ₂ O _2, fluorine-doped tin oxide (SnO _2: F), antimony-doped tin oxide Those doped with impurities such as (SnO ₂ : Sb), tin-doped indium oxide (In ₂ O ₃ : Sn), ZnO, Al-doped zinc oxide (ZnO: Al), and Ga-doped zinc oxide (ZnO: Ga) A single layer or laminated layer made of a material or the like formed into glass or a polymer can be used. The film thickness is not particularly limited, but is preferably about 3 nm to 10 μm. The glass or polymer surface may be flat, or the surface may be uneven. Further, as the current collector plate, a metal plate such as stainless steel, aluminum, copper, nickel, or a metal mesh can be used.

  The positive electrode may contain electrolytic manganese dioxide.

In the first nonaqueous electrolyte battery of the present invention, the nonaqueous electrolyte is not particularly limited. For example, an electrolytic solution containing a supporting salt, a gel electrolyte, or a solid electrolyte can be used. The supporting salt is not particularly limited, and for example, known supporting salts such as LiPF ₆ , LiClO ₄ , LiBF ₄ , Li (CF ₃ SO ₂ ) ₂ N can be used. The solvent of the electrolytic solution is not particularly limited. For example, ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (γ-BL), diethyl carbonate (DEC), dimethyl carbonate (DMC) For example, organic solvents used in conventional secondary batteries and capacitors, or a mixed solvent thereof can be used. Alternatively, ionic liquids such as 1-methyl-3-propylimidazolium bis (trifluorosulfonyl) imide and 1-ethyl-3-butylimidazolium tetrafluoroborate can be used. The concentration of the supporting salt is preferably 0.1 to 2.0M, and more preferably 0.8 to 1.2M. The gel electrolyte is not particularly limited, but for example, a polymer such as polyvinylidene fluoride, polyethylene glycol, or polyacrylonitrile, or a saccharide such as an amino acid derivative or sorbitol derivative is added with an electrolyte containing a supporting salt. And a gel electrolyte. Examples of the solid electrolyte include inorganic solid electrolytes and organic solid electrolytes. As the inorganic solid electrolyte, for example, a nitride of Li, an oxyacid salt, and the like are well known. Among _{them, Li 4 SiO 4, Li 4} SiO 4 -LiI-LiOH, xLi 3 PO 4 - (1-x) Li 4 SiO 4, Li 2 SiS 3, Li 3 PO 4 -Li 2 S-SiS 2, sulfide Examples thereof include phosphorus compounds. Examples of the organic solid electrolyte include polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyvinylidene fluoride, polyphosphazene, polyethylene sulfide, polyhexafluoropropylene, and derivatives thereof. These may be used alone or in combination.

  The non-aqueous electrolyte contains at least one halogen selected from the group consisting of iodine, bromine and chlorine together with lithium ions. Here, bromine or iodine is preferable as the halogen dissolved in the electrolyte. This is because even when halogen gas is generated and flows out of the battery, bromine and iodine are relatively less toxic than chlorine. In particular, iodine is preferable. This is because relatively good cycle characteristics can be obtained when iodine is used.

  The first nonaqueous electrolyte battery of the present invention may include a separator between the negative electrode and the positive electrode. The separator is not particularly limited as long as the composition can withstand the use range of the non-electrolyte battery. For example, a polymer nonwoven fabric such as a polypropylene nonwoven fabric or a polyphenylene sulfide nonwoven fabric, or a microporous film of an olefin resin such as polyethylene or polypropylene Is mentioned. These may be used alone or in combination.

  The shape of the first nonaqueous electrolyte battery of the present invention is not particularly limited, and examples thereof include a coin type, a button type, a sheet type, a laminated type, a cylindrical type, a flat type, and a rectangular type. Moreover, you may apply to the large sized thing etc. which are used for an electric vehicle etc. An example of the first non-electrolyte battery of the present invention is schematically shown in FIG. In this nonaqueous electrolyte battery 10, a negative electrode 14 and a positive electrode 16 made of a lithium metal foil are arranged to face each other with a nonaqueous electrolyte 18 therebetween. Among these, the positive electrode 16 is produced by mixing the conductive material 16b and the binder 16c and then press-molding the nickel mesh 16a as a current collector. The non-aqueous electrolyte 18 contains a halogen such as iodine in addition to a lithium salt such as lithium hexafluorophosphate.

  Next, the second nonaqueous electrolyte battery of the present invention will be described.

  In the second nonaqueous electrolyte battery of the present invention, the negative electrode can be the same as that of the first nonaqueous electrolyte battery of the present invention. Therefore, the description thereof is omitted here.

In the second nonaqueous electrolyte battery of the present invention, the positive electrode uses at least one halogen selected from the group consisting of iodine (I ₂ ), bromine (Br ₂ ), and chlorine (Cl ₂ ) as the positive electrode active material. This positive electrode contains at least one lithium halide selected from the group consisting of lithium iodide, lithium bromide and lithium chloride. Such halogen ions of lithium halide release electrons during charging to become halogen as a positive electrode active material and dissolve in the non-aqueous electrolyte. At this time, the lithium halide contained in the positive electrode is preferably lithium bromide or lithium iodide. This is because even if halogen gas derived from lithium halide flows out of the battery, bromine and iodine are relatively less toxic than chlorine. In particular, lithium iodide is preferable. This is because relatively good cycle characteristics can be obtained when lithium iodide is used. Moreover, as a density | concentration of the lithium halide contained in a positive electrode, it is desirable that it is 10 wt%-80 wt%. If the concentration of the lithium halide contained in the positive electrode is less than 10 wt%, it is not preferable because sufficient charge / discharge capacity cannot be obtained. In addition, when the concentration of lithium halide contained in the positive electrode exceeds 80 wt%, the relative amount of the conductive auxiliary agent such as carbon contained in the positive electrode is reduced, and a sufficient conductive path cannot be formed, so that sufficient charge / discharge capacity is achieved. In addition, it is not preferable because output characteristics cannot be obtained. The positive electrode may be formed by mixing a predetermined amount of the above-described lithium halide, conductive material, and binder and then press-molding the current collector. At this time, the mixing ratio of the conductive material and the binder is not particularly limited. For example, the binder may be 3 to 10 parts by weight with respect to 100 parts by weight of the conductive material. As a mixing method, wet mixing may be performed together with carbon powder or a binder in a solvent such as N-methylpyrrolidone, or dry mixing may be performed using a mortar or the like. As such a conductive material, binder, and current collector, those similar to the first non-aqueous electrolyte battery of the present invention can be used, and therefore, the description thereof is omitted here.

  The positive electrode may contain electrolytic manganese dioxide.

  In the second nonaqueous electrolyte battery of the present invention, the same nonaqueous electrolyte as that of the first nonaqueous electrolyte battery of the present invention can be used. Therefore, the description thereof is omitted here.

  Since the shape of the second nonaqueous electrolyte battery of the present invention can be the same as that of the first nonaqueous electrolyte battery of the present invention, description thereof is omitted here. An example of the second nonaqueous electrolyte battery of the present invention can also have the same configuration as in FIG. However, in FIG. 1, the positive electrode 16 is manufactured by mixing lithium halide such as lithium iodide in addition to the conductive material 16 b and the binder 16 c and then press-molding the nickel mesh 16 a as a current collector. The nonaqueous electrolyte 18 includes a lithium salt such as lithium hexafluorophosphate, but may or may not include a halogen such as iodine.

  Hereinafter, specific examples of the present invention will be described using examples. The following Examples 1 to 4 correspond to specific examples of the first nonaqueous electrolyte battery of the present invention, and Examples 5 to 7 correspond to specific examples of the second nonaqueous electrolyte battery of the present invention.

[Example 1]
The positive electrode was prepared as follows. First, 100 mg of ketjen black (ECP-600JD manufactured by Mitsubishi Chemical), 10 mg of Teflon powder (manufactured by Daikin Industries, Teflon is a registered trademark), and 10 mg of electrolytic manganese dioxide (manufactured by Mitsui Mine) are kneaded together using a mortar in a sheet form. The positive electrode member was obtained. 6 mg of this positive electrode member was pressure-bonded to a nickel mesh to obtain a positive electrode.

  For the negative electrode, metallic lithium (made by Tanaka Kikinzoku) having a diameter of 10 mm and a thickness of 0.5 mm was used. A positive electrode and a negative electrode were set in a F-type electrochemical cell (see FIG. 2) manufactured by Hokuto Denko in a glove box under an argon atmosphere, and a 1M lithium hexafluorophosphate mixed solution of ethylene carbonate and diethyl carbonate (weight ratio 3) : 7, manufactured by Toyama Pharmaceutical Co., Ltd.) 5 mL of 0.05 M iodine dissolved therein was injected as an electrolyte. The gas reservoir of this F-type electrochemical cell was filled with argon to obtain a nonaqueous electrolyte battery. In this F-type electrochemical cell, the positive electrode and the negative electrode are electrically insulated via a resin (not shown).

  The F-type electrochemical cell thus assembled was connected to a charge / discharge device (model name HJ1001SM8A) manufactured by Hokuto Denko, and a constant current of 1.0 mA was passed between the positive electrode and the negative electrode, and the open-circuit voltage was 2. The battery was discharged to 0V and then charged to 4.2V (this cycle was repeated twice). As a result, the charge / discharge capacity per weight of the positive electrode member was 1000 mAh / g for the first discharge capacity and 12000 mAh / g for the charge capacity. Further, the second discharge capacity was 9000 mAh / g, and the charge capacity was 10,000 mAh / g.

[Example 2]
A nonaqueous electrolyte battery was assembled in the same manner as in Example 1. This nonaqueous electrolyte battery was charged and discharged once under the same conditions except that the 1.0 mA charge / discharge current of Example 1 was changed to 0.1 mA. As a result, the charge / discharge capacity per weight of the positive electrode member was 1000 mAh / g, and the charge capacity was 2100 mAh / g.

[Example 3]
A nonaqueous electrolyte battery was assembled in the same manner as in Example 2 except that the 0.05M iodine concentration in Example 2 was changed to 0.1M. This nonaqueous electrolyte battery was charged and discharged once under the same conditions as in Example 2. As a result, the charge / discharge capacity per weight of the positive electrode member was 2400 mAh / g for the discharge capacity and 12100 mAh / g for the charge capacity.

[Example 4]
A nonaqueous electrolyte battery was assembled in the same manner as in Example 1 except that 0.05 M iodine in Example 1 was replaced with 0.1 M bromine. This nonaqueous electrolyte battery was charged and discharged once under the same conditions as in Example 1. As a result, the charge / discharge capacity per weight of the positive electrode member was a discharge capacity of 2400 mAh / g and a charge capacity of 34000 mAh / g.

[Example 5]
The positive electrode was prepared as follows. First, 100 mg of ketjen black (ECP-600JD manufactured by Mitsubishi Chemical), 10 mg of Teflon powder (manufactured by Daikin Industries, Teflon is a registered trademark), 10 mg of electrolytic manganese dioxide (manufactured by Mitsui Mine), and 100 mg of lithium iodide (manufactured by Aldrich) It knead | mixed using the mortar with the dry type, and obtained the sheet-like positive electrode member. 6 mg of this positive electrode member was pressure-bonded to a nickel mesh to obtain a positive electrode.

  For the negative electrode, metallic lithium (made by Tanaka Kikinzoku) having a diameter of 10 mm and a thickness of 0.5 mm was used. A positive electrode and a negative electrode were set in a F-type electrochemical cell (see FIG. 2) manufactured by Hokuto Denko in a glove box under an argon atmosphere, and a 1M lithium hexafluorophosphate mixed solution of ethylene carbonate and diethyl carbonate (weight ratio 3) : 7, Toyama Pharmaceutical) was injected as an electrolyte. The gas reservoir of this F-type electrochemical cell was filled with argon to obtain a nonaqueous electrolyte battery. In this F-type electrochemical cell, the positive electrode and the negative electrode are electrically insulated via a resin (not shown).

  The F-type electrochemical cell assembled in this way was connected to a charge / discharge device (model name HJ1001SM8A) manufactured by Hokuto Denko, and a constant current of 1.0 mA was passed between the positive electrode and the negative electrode, and the open-circuit voltage was 4. The battery was charged to 2V, and then discharged to 2.0V. As a result, the discharge capacity per weight of the positive electrode member was 2000 mAh / g for the first charge capacity and 1300 mAh / g for the discharge capacity. When charging / discharging was repeated 10 times, the charging / discharging capacity after the second time changed around 1000 mAh / g (see FIG. 3).

[Example 6]
A nonaqueous electrolyte battery was assembled in the same manner as in Example 5 except that 100 mg of lithium iodide in Example 5 was replaced with 100 mg of lithium bromide (Aldrich). This nonaqueous electrolyte battery was charged and discharged once under the same conditions as in Example 5. As a result, the charge / discharge capacity per weight of the positive electrode member was 1900 mAh / g for the charge capacity and 1600 mAh / g for the discharge capacity.

[Example 7]
A nonaqueous electrolyte battery was assembled in the same manner as in Example 5 except that electrolytic manganese dioxide was not added to the positive electrode member of Example 5. This nonaqueous electrolytic battery was charged and discharged under the same conditions as in Example 5. As a result, the charge / discharge capacity per positive electrode member weight was 2800 mAh / g for the first charge capacity and 1500 mAh / g for the discharge capacity. Moreover, when charging / discharging was repeated 10 times, the charging / discharging capacity | capacitance after the 2nd time changed around 1000-1600 mAh / g (refer FIG. 4).

[Comparative Example 1]
A non-aqueous electrolyte battery was assembled in the same manner as in Example 1 except that 0.05 M iodine was not added to the electrolytic solution in Example 1. In Comparative Example 1, it can also be said that a nonaqueous electrolyte battery was assembled in the same manner as in Example 5 except that lithium iodide was not added to the positive electrode of Example 5. Therefore, the comparative example 1 is a comparative example of the first example and a comparative example of the fifth example. The non-aqueous electrolyte battery was charged by passing a constant current of 1.0 mA between the positive electrode and the negative electrode until the open-end voltage reached 4.2V, and then discharged until 2.0V. As a result, the charge / discharge capacity per weight of the positive electrode member was 50 mAh / g at the maximum.

  The nonaqueous electrolyte battery of the present invention can be used mainly in the electrochemical industry, for example, a power source for hybrid vehicles and electric vehicles, a power source for consumer electric appliances such as mobile phones and personal computers, and load leveling (load leveling). Can be used for electrochemical devices.

It is a schematic diagram of the nonaqueous electrolyte battery of this invention. It is a schematic diagram of an F-type electrochemical cell. It is a graph showing the change of the charging / discharging capacity of Example 5. It is a graph showing the change of the charging / discharging capacity of Example 7.

Explanation of symbols

  10 nonaqueous electrolyte battery, 14 negative electrode, 16 positive electrode, 16a nickel mesh, 16b conductive material, 16c binder, 18 nonaqueous electrolyte.

Claims (4)

A non-aqueous electrolyte battery in which a negative electrode using a material that absorbs and releases lithium ions as a negative electrode active material and a positive electrode using halogen as a positive electrode active material are arranged via a non-aqueous electrolyte containing lithium ions,
The non-aqueous electrolyte contains at least one halogen selected from the group consisting of iodine, bromine and chlorine;
Non-aqueous electrolyte battery. The halogen concentration contained in the non-aqueous electrolyte is 0.05 M or more and a saturation concentration or less.
The nonaqueous electrolyte battery according to claim 1. A non-aqueous electrolyte battery in which a negative electrode using a material that absorbs and releases lithium ions as a negative electrode active material and a positive electrode using halogen as a positive electrode active material are arranged via a non-aqueous electrolyte containing lithium ions,
The positive electrode includes at least one lithium halide selected from the group consisting of lithium iodide, lithium bromide, and lithium chloride;
Non-aqueous electrolyte battery. The concentration of the lithium halide contained in the positive electrode is 10 wt% to 80 wt%.
The nonaqueous electrolyte battery according to claim 3.