JP4399882B2 - Solid electrolyte, lithium secondary battery and electric double layer capacitor - Google Patents

Description

【００６１】
本発明の実施例の電池は、比較例の電池に比べて内部抵抗が低いことから、固体電解質と電極との接着性が向上しているものと推測される。
【００６２】
（２）サイクル特性
実施例および比較例のリチウム２次電池のサイクル特性を調べた。サイクル特性は、２．８Ｖ〜４．２Ｖの間の条件で充放電を１００サイクル繰り返し、初期の放電容量で１００サイクル後の放電容量を除した値である容量保持率で示した。その結果を表２に示した。
【００６３】
【表２】

【００６４】
実施例５：電気２重層キャパシタ
実施例１で作製したゲル電解質溶液に活性炭粉末（大阪ガス製、スーパー活性炭Ｍ−２０）を混合し、これをアルミニウム箔上に塗布し、Ａｃを乾燥除去した。この電極を直径１５mmの円形状に２枚切り抜き、この電極で上記実施例１で作製したゲル電解質フィルム（直径２０mmに切り抜いたもの）をはさみ、これをアルミラミネート袋に挿入しリード取り出し部をヒートシールし実施例の電気２重層キャパシタとした。一方、ゲル電解質フィルムにプラズマ処理をしなかったこと以外は、上記実施例と同様にして比較例の電気２重層キャパシタを作製した。
【００６５】
これらの実施例と比較例の電気２重層キャパシタにつき内部抵抗を測定したところ、実施例の電気２重層キャパシタの内部抵抗は、比較例の電気２重層キャパシタの内部抵抗を「１」としたとき、０．８５と小さかった。
【００６６】
【発明の効果】
以上のように本発明によれば、集電体、電極との接着性が良好で、内部抵抗が小さく、しかも保存特性も良好な固体電解質、これを用いたリチウム２次電池および電気２重層キャパシタを提供可能となった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid electrolyte suitably used for an electrochemical device such as a lithium secondary battery, an electric double layer capacitor, a sensor, an electrochromic display, and a wet solar cell, and a lithium secondary battery using this solid electrolyte, electric 2 The present invention relates to a multilayer capacitor.
[0002]
[Prior art]
Secondary batteries used in portable personal computers, video cameras, and the like are required to have a high energy density and a long charge / discharge cycle life. Conventionally, lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and the like have been used as secondary batteries, but lithium ion secondary batteries have been put to practical use as secondary batteries with higher energy density.
[0003]
Conventionally, a liquid is generally used as the electrolyte of such a secondary battery. However, if the electrolyte can be made solid, liquid leakage can be prevented and a sheet structure can be formed. For this reason, the battery using a solid electrolyte attracts attention as a next generation type. In particular, if a lithium ion secondary battery, which is currently widely used in portable personal computers and the like, can be made into a sheet and laminated and miniaturized, it is expected that the application range will be further expanded.
[0004]
As such a solid electrolyte, for example, a system in which an electrolyte salt is dissolved in a polymer is known. However, such a solid electrolyte containing no solvent (for example, a lithium oxide in which polyethylene oxide is compatible) has low electrical conductivity (10 ⁻⁴ S · cm ⁻¹ or less) and has not yet been put into practical use. On the other hand, gel-like polymer solid electrolytes composed of a polymer, an electrolyte salt and a solvent have recently attracted attention.
[0005]
Such a gel-like solid polymer electrolyte (hereinafter referred to as “gel electrolyte”) has a conductivity of 10 ⁻³ S · cm ⁻¹ which is close to that of a liquid.
[0006]
For example, US Pat. No. 5,296,318 discloses a solution in which a lithium salt is dissolved in a copolymer [P (VDF-HFP)] of vinylidene fluoride (VDF) and 8 to 25% by weight of propylene hexafluoride (HFP). A gel electrolyte containing 20 to 70% by weight is disclosed. The conductivity of this gel electrolyte reaches 10 ⁻³ S · cm ⁻¹ . Originally, polyvinylidene fluoride (PVDF) is a crystalline polymer that is relatively excellent in chemical resistance. That is, there is a solvent that dissolves PVDF well, but it does not dissolve in any solvent, and it is one of the easy-to-use resins among fluororesins. In fact, PVDF is used as a binder for positive and negative electrode active materials of lithium ion secondary batteries. PVDF described in the above patent is a copolymer of VDF and HFP, and HFP reduces the crystallinity of PVDF. Such a VDF-HFP copolymer can contain a large amount of a solvent, and crystal precipitation of a lithium salt is also suppressed, so that a gel electrolyte having mechanical strength can be produced.
[0007]
Thus, it has been conventionally proposed to use a fluorinated polymer as the polymer for holding the electrolyte solution. However, the fluorine-based polymer has a problem that it is inferior in adhesiveness and inferior in adhesive strength with a metal (aluminum, copper, etc.) as a current collector. In order to improve this, in International Patent No. WO95 / 31836, the electrode is coated with the same polymer as the electrode, or the current collector is coated with an ethylene-acrylic acid copolymer to adhere the current collector to the electrode. Improves sex. Thus, in the thing of international patent WO95 / 31836, it was necessary to process a collector, and there existed a problem that the number of processes increased and the increase in battery cost was caused.
[0008]
Further, since it is a resin-based material, it has contributed to cycle deterioration.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a solid electrolyte capable of reducing internal resistance by improving adhesion to a current collector and / or electrode, which is a drawback of conventional gel electrolytes, and a lithium secondary battery and an electric double layer capacitor using the same. Is to provide.
[0010]
[Means for Solving the Problems]
The object of the present invention is achieved by the following configurations (1) to ( 6 ).
(1) A gel electrolyte supported on a porous sheet-like substrate, a copolymer of polyvinylidene fluoride and propylene hexafluoride, or a main chain made of a copolymer of vinylidene fluoride and chlorofluoroethylene. A solid electrolyte obtained by subjecting a thermoplastic fluororesin having a chain made of polyvinylidene fluoride to gelation by holding an electrolyte solution.
(2) A lithium secondary battery having the solid electrolyte of (1 ) above.
(3) A lithium secondary battery in which at least one of the electrodes has the composition of the solid electrolyte and the electrode active material of (1) above.
(4) An electric double layer capacitor having the solid electrolyte of (1 ) above.
(5) An electric double layer capacitor in which at least one of the polarizable electrodes has the composition of the solid electrolyte of (1) and an electrode active material.
(6) A gel electrolyte supported on a porous sheet-like substrate, a copolymer of polyvinylidene fluoride and propylene hexafluoride, or a main chain made of a copolymer of vinylidene fluoride and chlorofluoroethylene. A method for producing a solid electrolyte, comprising a step of subjecting a thermoplastic fluororesin having a chain made of polyvinylidene fluoride to a gel by holding an electrolyte solution to obtain a solid electrolyte.
[0011]
[Action]
Since the surface of the solid electrolyte of the present invention is plasma-treated, the retention property of the gel electrolyte material is also increased, and the vicinity of the surface is roughened, resulting in excellent adhesion to the electrode or current collector, A battery having low internal resistance and good cycle characteristics can be obtained. A similar effect can be obtained with an electric double layer capacitor.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The solid electrolyte of the present invention is obtained by subjecting a polymer substance capable of holding an electrolyte solution to plasma treatment, holding the electrolyte solution therein, and then gelling the gel, or by holding the electrolyte solution in the polymer substance and gelling. And then obtained by plasma treatment. In the present invention, the solid electrolyte is mainly in the form of a sheet. When the sheet is formed in this way, the solid electrolyte alone may be used, or the solid electrolyte may be supported on a sheet-like porous film (including a nonwoven fabric). In the form of a solid electrolyte supported on a sheet-like porous membrane, it is possible to use a polymer substance that could not be used as a gel electrolyte material because it is impossible to form a self-supporting membrane in the past. It is excellent and the thickness can be reduced. Hereinafter, the present invention will be described in detail.
[0013]
In the present invention, there is a case where the solid electrolyte is supported on the porous film as described above, so that the present invention is not limited to a polymer substance that can be independently formed as a self-supporting film. Since a self-supporting film cannot be formed, a polymer substance that could not be conventionally used as a gel electrolyte material can also be used.
[0014]
Specific examples of the polymer substance that can be used in the present invention include known gel-type SPE polymers. As such a polymer, for example,
1) A polymer of an acrylate containing ethylene oxide which is a photopolymerizable monomer and a polyfunctional acrylate,
2) polyacrylonitrile,
3) Polyalkylene oxides such as polyethylene oxide and polypropylene oxide,
4) Polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trifluoroethylene chloride (CTFE) copolymer [P (VDF-CTFE)], vinylidene fluoride-hexafluoro Fluoropolymers such as propylene fluororubber, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene fluororubber [P (VDF-TFE-HFP)], vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether fluororubber, etc. preferable. As the vinylidene fluoride-based polymer, those in which vinylidene fluoride is 50% by weight or more, particularly 70% by weight or more are preferable, and in particular, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene (HFP), A copolymer of vinylidene fluoride and ethylene trifluoride chloride [P (VDF-CTFE)] is preferred. The VDF-CTFE copolymer is sold, for example, under the trade name “Sephral Soft (G150, G180)” from Central Glass Co., Ltd., and under the trade name “Solef 31508” from Nippon Solvay Co., Ltd. VDF-HFP copolymer is available from Nippon Solvay Co., Ltd. under the trade names “KynarFlex2750 (VDF: HFP = 85: 15 wt%)”, “KynarFlex2801 (VDF: HFP = 90: 10 wt%)”, etc. from Elf Atchem. Are sold under the trade names “Solef 11008”, “Solef 11010”, “Solef 21508”, “Solef 21510” and the like.
[0015]
Of the above polymer substances, for example, [P (VDF-TFE-HFP)] has been conventionally able to be gelled with an electrolyte solution, but it has been difficult to form a self-supporting film. However, in the present invention, it is possible to form a self-supporting film by holding [P (VDF-TFE-HFP)] gelled with the electrolyte solution in the porous film.
[0016]
Electrolyte solution The electrolyte may be appropriately selected according to the type of battery to be applied. For example, when applied to a lithium secondary battery, one or more selected from LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiSO ₃ CF ₃ , (CF ₃ SO ₂ ) ₂ NLi, etc. are used. That's fine.
[0017]
The solvent of the electrolyte solution is preferably one that does not decompose even when a high voltage is applied in consideration of application to a lithium secondary battery, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene. Carbonates, carbonates such as dimethyl carbonate (DMC), diethyl carbonate, ethyl methyl carbonate, tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyldioxolane, γ-butyrolactone, sulfolane, 3-methylsulfolane Nonaqueous solvents such as dimethoxyethane, diethoxyethane, ethoxymethoxyethane, and ethyldiglyme are preferred.
[0018]
The electrolyte is dissolved in the solvent as described above to obtain an electrolyte solution. The concentration of the non-aqueous solvent-based electrolyte salt is preferably 0.5 to 3 mol / liter.
[0019]
Gel electrolyte A specific method for producing the gel electrolyte is described below. The production is preferably carried out in a dry room or glove box with low moisture. First, the polymer is dispersed and dissolved in a solvent. The solvent at this time may be appropriately selected from various solvents in which the polymer can be dissolved. For example, tetrahydrofuran (THF), acetone, methyl acetate and the like are preferably used, and tetrahydrofuran (THF) is particularly preferable. The concentration of the polymer with respect to the solvent is preferably 5 to 25% by weight.
[0020]
Next, an electrolytic solution is added to the polymer solution. The content of the electrolytic solution is preferably polymer: electrolytic solution = 50: 50 wt% to 20:80 wt%. A mixed solution of a polymer solution and an electrolytic solution (hereinafter referred to as “gel electrolyte solution”) is applied on a flat substrate. This substrate may be anything that is smooth. For example, polyester film, glass, polytetrafluoroethylene film and the like. The means for applying the gel electrolyte solution to the substrate is not particularly limited, and may be appropriately determined according to the material and shape of the substrate. In general, a metal mask printing method, an electrostatic coating method, a dip coating method, a spray coating method, a roll coating method, a doctor blade method, a gravure coating method, a screen printing method and the like are used. Thereafter, a rolling process is performed by a flat plate press, a calender roll or the like as necessary.
[0021]
After the application, if the solvent when the polymer is dissolved is evaporated, a gel electrolyte sheet or film is completed. The temperature at which the solvent is evaporated may be room temperature, but may be heated. The resulting gel electrolyte is translucent and elastic, and currently has a thickness of about 20 to 200 μm.
[0022]
The plasma treatment of the sheet gel electrolyte may be performed on the above substrate or may be peeled off from the substrate.
[0023]
The sheet-like gel electrolyte may be produced by applying the above polymer solution on a substrate, drying it, performing plasma treatment, and then impregnating the electrolyte solution.
[0024]
The sheet-like gel electrolyte may be further prepared by applying the gel electrolyte to a sheet-like porous film and supporting it to form a sheet. In this case, it can be used as a battery separator or the like as it is. The plasma treatment is also performed as it is.
[0025]
The porous membrane is made of a material such as polyethylene or polypropylene, and preferably has an average pore diameter of about 0.01 to 1 μm and a porosity of about 30 to 60%. As this porous membrane, a non-woven fabric can also be used. Therefore, this porous membrane may be different from the separator conventionally used in the solution system in the material, the average pore diameter, the porosity, and the like.
[0026]
In this method, the above-mentioned polymer substance may be supported on a porous membrane and impregnated by, for example, being immersed in an electrolyte solution (which may be heated if necessary) to be gelled. . The porous film is loaded with a polymer substance by spraying the polymer substance onto the porous film together with a binder, or by mixing the polymer substance and a resin, forming a sheet, and then stretching the film. For example, there is a method in which a polymer material is supported on a membrane.
[0027]
In addition, a microporous film made of a polymer material to be gelled may be prepared by using a well-known technique for producing a microporous film without using a porous film, and may then be impregnated with an electrolyte and gelled. . In this case, for example, PC (propylene carbonate) or DBP (dibutyl phthalate) may be added to the polymer material to form a film, and then PC or DBP may be extracted to form a microporous film. Alternatively, holes may be made in the membrane by a perforation method. In any case, after the polymer film to be gelled as a porous material is produced, it may be swollen in the electrolyte solution.
[0028]
The resin mixed with the polymer substance capable of holding the electrolyte solution is not particularly limited as long as it can be formed into a film by stretching and can be made porous by stretching. Various resins having crystallinity, for example, Although it may be appropriately selected from polyolefin, polyamide, halogen-containing vinyl polymer, polyester, etc., polyolefin is preferably used. As the polyolefin, polyethylene and polypropylene are preferable, and polyethylene is particularly preferable.
[0029]
Plasma treatment The plasma treatment in the present invention is preferably a low-temperature plasma treatment, and is preferably carried out using nitrogen gas, argon gas (inert gas) or the like as a treatment gas. The plasma processing conditions are not particularly limited, and the electrode arrangement, applied current, plasma output, processing time, operating pressure, and the like may be the same as those for normal plasma processing conditions. Usually, the plasma output is 0.5 to 5 kW, the processing time is 1 to 1000 seconds, and the operating pressure is 0.01 to 10 Torr. Further, the flow rate of the processing gas may be 5 to 100 SCCM. There is no restriction | limiting in particular about the frequency of a plasma processing power supply, Any may be direct current | flow-microwave.
[0030]
By this plasma treatment, the adhesion of the surface of the solid electrolyte to the current collector or electrode formed of the metal (alloy) of the battery is improved. The reason is not clarified at the present time, but it is considered that the film surface is roughened and easily adhered by plasma treatment.
[0031]
Battery and electric double layer capacitor The battery to which the gel electrolyte of the present invention is applied is not particularly limited, but various lithium secondary batteries such as a sheet type and a cylindrical type are particularly preferable. The gel electrolyte supported on the porous membrane can also be used as a separator.
[0032]
The electrode combined with the gel electrolyte preferably uses a composition comprising an electrode active material, the gel electrolyte, and, if necessary, a conductive additive.
[0033]
A negative electrode active material such as a carbon material, lithium metal, lithium alloy or oxide material is used for the negative electrode, and a positive electrode active material such as an oxide or carbon capable of intercalating and deintercalating lithium ions is used for the positive electrode. It is preferable to use a substance. By using such an electrode, a lithium secondary battery having good characteristics can be obtained.
[0034]
The carbon material used as the electrode active material may be appropriately selected from, for example, mesophase carbon microbeads (MCMB), natural or artificial graphite, resin-fired carbon material, carbon black, carbon fiber, and the like. These are used as powders.
[0035]
The oxide capable of intercalating and deintercalating lithium ions is preferably a composite oxide containing lithium, and examples thereof include LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , and LiV ₂ O ₄ . The average particle size of the oxide powder is preferably about 1 to 40 μm.
[0036]
The conductive auxiliary agent added as necessary preferably includes metals such as graphite, carbon black, carbon fiber, nickel, aluminum, copper, and silver, and graphite and carbon black are particularly preferable.
[0037]
The electrode composition is preferably in the range of active material: conductive auxiliary agent: gel electrolyte = 30 to 90: 3 to 10:10 to 70% by weight in the positive electrode, and active material: conductive auxiliary agent: gel electrolyte = 30 to 90 in the negative electrode. The range of 0-10: 10-70 weight% is preferable.
[0038]
In the present invention, the negative electrode active material and / or the positive electrode active material, preferably both active materials are mixed in the above-described gel electrolyte solution and adhered to the current collector surface.
[0039]
For example, the electrode coating solution obtained by mixing a gel electrolyte solution with an active material, and if necessary, a conductive material such as a carbon material or a metal, is applied onto a current collector such as a copper foil or an aluminum foil. It is made by evaporating. In addition, a metal foil, a metal mesh, etc. are normally used for a collector. The metal mesh has a smaller contact resistance with the electrode than the metal foil. However, in the case of the gel electrolyte of the present invention, the contact resistance is sufficiently small even with the metal foil.
[0040]
Thus, by using the same polymer material as the gel electrolyte for the electrode, the adhesion with the gel electrolyte is improved and the internal resistance is reduced. When lithium metal or a lithium alloy is used for the negative electrode active material, the composition of the negative electrode active material and the gel electrolyte need not be used.
[0041]
Furthermore, the polymer solid electrolyte and electrode of the present invention are also effective for electric double layer capacitors.
[0042]
The current collector used for the polarizable electrode may be a conductive rubber such as conductive butyl rubber, or may be formed by thermal spraying of a metal such as aluminum or nickel, and a metal mesh is formed on one surface of the electrode layer. It may be attached.
[0043]
Such a polarizable electrode and the gel electrolyte are combined in an electric double layer capacitor.
[0044]
Examples of the electrolyte salt include (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₃ MeNBF ₄ , and (C ₂ H ₅ ) ₄ PBF ₄ .
[0045]
The nonaqueous solvent used for the electrolytic solution may be various known ones, and for example, propylene carbonate, ethylene carbonate, γ-butyrolactone, acetonitrile, dimethylformamide, 1,2-dimethoxyethane, sulfolane alone or a mixture is preferable.
[0046]
The concentration of the electrolyte in such a nonaqueous solvent electrolyte solution may be 0.5 to 3 mol / liter.
[0047]
An insulating material such as polypropylene or butyl rubber may be used as the insulating gasket.
[0048]
The structure of the electric double layer capacitor in which the gel electrolyte of the present invention is used is not particularly limited. Any of the so-called coin type, paper type, laminated type and the like may be used.
[0049]
【Example】
Hereinafter, specific examples of the present invention will be shown to describe the present invention in more detail.
Example 1
Gel electrolyte polymer material PVDF Kynar 2801 (manufactured by Elf Atchem)
(Copolymer of polyvinylidene fluoride and hexafluoropropylene)
Electrolytic solution 1M LiClO ₄ / PC solvent (EC + PC, mixed solvent of ethylene carbonate: propylene carbonate = 1: 1 (volume ratio)) (abbreviated as EL)
Solvent Acetone (abbreviated as Ac)
The above components were mixed at room temperature with PVDF: EL: Ac = 3: 7: 20 at room temperature and dissolved to prepare a gel electrolyte solution.
[0050]
This gel electrolyte solution was applied to a width of 50 mm by a doctor blade method on a polyethylene terephthalate (PET) film. This was air-dried for 1 hour, and Ac was evaporated to obtain a transparent gel electrolyte film (sheet) made of PVDF / 1M LiClO ₄ / PC solvent (mixed solvent of EC: PC = 1: 1 (volume ratio)). . The film thickness was 90 μm.
[0051]
This gel electrolyte film was cut into a circle having a diameter of 25 mm and subjected to low-temperature plasma treatment. The conditions are listed below.
[0052]
Process gas and its flow rate: Argon 10 SCCM
Operating pressure: 1 Torr
Plasma output: 1kW
Processing time: 30 seconds, operating pressure is 1 Torr
Plasma frequency: 13 MHz
[0053]
45 g of the gel electrolyte solution, placed in a homogenizer container, 10.8 g of lithium cobaltate (Seimi Chemical Co., particle size 2 to 3 μm) and 1.35 g of acetylene black (trade name HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) Added and dispersed at 12000 rpm for 5 minutes at room temperature. This coating solution was printed on an aluminum foil (length 20 mm, width 20 mm, thickness 20 μm) in a circular shape with a diameter of 10 mm with a metal mask printer, and air-dried for 1 hour to evaporate acetone. The thickness of this electrode was 0.1 mm. Using this electrode as a positive electrode, a copper foil (vertical 20 mm, horizontal 20 mm, thickness 20 μm) coated with the above gel electrolyte film and a negative electrode material having the following composition is laminated in this order, and finally placed in a coin can. A lithium secondary battery was produced. The negative electrode material was composed of 45 g of the gel electrolyte, 12 g of graphite, 1 g of a conductive additive and a homogenizer in the same manner as the positive electrode to form a paste.
[0054]
Example 2
In this example, a lithium secondary battery of Example 2 was produced in the same manner as Example 1 except that a thermoplastic fluororesin was used as the polymer substance. Specifically, as the thermoplastic fluororesin, trade name Cefalsoft (manufactured by Central Glass Co., Ltd .: main chain is made of a copolymer of vinylidene fluoride and chlorofluoroethylene, and side chain is made of polyvinylidene fluoride. Used).
[0055]
Example 3
The PVDF in Example 1 was dissolved in Ac so that the PVDF concentration was 10% by weight to obtain a PVDF: PC: Ac = 3: 7: 20 ratio, and a polymer material solution was prepared. This polymer material solution was applied onto a substrate in the same manner as in Example 1 and dried to form a polymer material film. The polymer material film had a thickness of 100 μm. This polymer material film was subjected to plasma treatment in the same manner as in Example 1, and this was impregnated with the above electrolyte solution to obtain a gel electrolyte film. A lithium secondary battery of Example 3 was produced in the same manner as in Example 1 except that this gel electrolyte film was used.
[0056]
Example 4
The gel electrolyte solution of Example 1 was applied and impregnated by a doctor blade method onto a polypropylene-based nonwoven fabric having a thickness of 50 μm. The gel electrolyte solution was applied and impregnated so that the total film thickness was 50 μm.
[0057]
A lithium secondary battery of Example 3 was produced in the same manner as in Example 1 except that the above gel electrolyte solution-coated nonwoven fabric was subjected to plasma treatment in the same manner as in Example 1.
[0058]
Comparative Examples Lithium secondary batteries for Examples 1 to 4 were produced in the same manner as the Examples, except that the plasma treatment was not performed in Examples 1 to 4.
[0059]
Evaluation Method (1) Internal Resistance The internal resistance of the lithium secondary batteries of Examples and Comparative Examples was measured. Table 1 shows the results. All of the examples had lower internal resistance than that of the comparative example. In Table 1, the internal resistance of the comparative example corresponding to each was set to 1, and the internal resistance of the example was shown as a relative value with respect thereto. The internal resistance was measured from 1 Hz to 100 kHz by the AC impedance method, and the resistance at 1 kHz was used.
[0060]
[Table 1]

[0061]
Since the battery of the Example of this invention has low internal resistance compared with the battery of a comparative example, it is estimated that the adhesiveness of a solid electrolyte and an electrode is improving.
[0062]
(2) Cycle characteristics The cycle characteristics of the lithium secondary batteries of Examples and Comparative Examples were examined. The cycle characteristics are indicated by a capacity retention rate which is a value obtained by dividing charge and discharge for 100 cycles under a condition between 2.8 V and 4.2 V, and dividing the discharge capacity after 100 cycles by the initial discharge capacity. The results are shown in Table 2.
[0063]
[Table 2]

[0064]
Example 5: Electric Double Layer Capacitor Activated carbon powder (Super Activated Carbon M-20, manufactured by Osaka Gas Co., Ltd.) was mixed with the gel electrolyte solution prepared in Example 1, and this was applied onto an aluminum foil to remove Ac by drying. Cut out two of these electrodes into a circular shape with a diameter of 15 mm, sandwich the gel electrolyte film (cut out to a diameter of 20 mm) prepared in Example 1 with this electrode, insert it into an aluminum laminate bag, and heat the lead takeout part. An electric double layer capacitor of the example was sealed. On the other hand, an electric double layer capacitor of a comparative example was produced in the same manner as in the above example except that the gel electrolyte film was not subjected to plasma treatment.
[0065]
When the internal resistance of the electric double layer capacitor of these examples and comparative examples was measured, the internal resistance of the electric double layer capacitor of the example was “1” when the internal resistance of the electric double layer capacitor of the comparative example was “1”. It was as small as 0.85.
[0066]
【The invention's effect】
As described above, according to the present invention, a solid electrolyte having good adhesion to a current collector and electrodes, low internal resistance, and good storage characteristics, a lithium secondary battery and an electric double layer capacitor using the same Can be provided.

Claims (6)

Gel electrolyte supported on a porous sheet-like substrate, or a copolymer of polyvinylidene fluoride and propylene hexafluoride, or a main chain of a copolymer of vinylidene fluoride and chlorofluoroethylene, and a side chain of A solid electrolyte obtained by subjecting a thermoplastic fluororesin having a structure made of vinylidene fluoride to gelation by holding an electrolyte solution. A lithium secondary battery comprising the solid electrolyte of claim 1 .   A lithium secondary battery in which at least one of the electrodes has the composition of the solid electrolyte and the electrode active material according to claim 1. An electric double layer capacitor having the solid electrolyte of claim 1 .   An electric double layer capacitor in which at least one of the polarizable electrodes has the composition of the solid electrolyte of claim 1 and an electrode active material. Gel electrolyte supported on a porous sheet-like substrate, or a copolymer of polyvinylidene fluoride and propylene hexafluoride, or a main chain of a copolymer of vinylidene fluoride and chlorofluoroethylene, and a side chain of A method for producing a solid electrolyte, comprising a step of subjecting a thermoplastic fluororesin having a structure made of vinylidene fluoride to a gelation by holding an electrolyte solution to obtain a solid electrolyte.