JPH08124570A - Polymer electrode, manufacture thereof and lithium secondary battery - Google Patents

Abstract

PURPOSE: To provide a polymer electrode increasing energy density and charge/ discharge efficiency to improve a charge/discharge cycle characteristic, by providing a π electron shared conductive high polymer layer between layers of containing an organic disulfide compound or the like, in the uppermost part and in the lowermost part. CONSTITUTION: Layers 4a to 4c, containing an organic disulfide compound, metal oxide and π electron shared conductive high polymer further to contain as necessary an electrolyte having metal cation, and layers 3a to 3d mainly composed of the π electron shared conductive high polymer are alternately laminated. Here are formed layers in the uppermost/lowermost parts into the layers 3a, 3d mainly composed of π electron shared conductive high polymer. These layers are formed on a carbon film electrode current collector 1 and titanium foil 2, to obtain a polymer electrode suited for a positive electrode of a lithium secondary cell or the like. In the organic disulfide compound, by electrolytic reduction and oxidation, S-S bond is made into cleavage and regenerated to S-metal ion bond. The π electron shared conductive high polymer is preferable polyaniline in a dedoped reduction condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrode made of an organic compound used in electrochemical devices such as batteries, electrochromic display devices, sensors and memories, a method for producing the same, and lithium using the polymer electrode as a positive electrode. Regarding secondary batteries.

[0002]

2. Description of the Related Art Since the discovery of conductive polyacetylene in 1971, the use of conductive polymers as electrode materials has led to lightweight and high energy density batteries, large-area electrochromic devices, and living things using microelectrodes. Conductive polymer electrodes are being actively studied because electrochemical elements such as chemical sensors can be expected. Since polyacetylene is unstable and poor in practicality as an electrode, other π-electron conjugated conductive polymers have been studied, and relatively stable polymers such as polyaniline, polypyrrole, polyacene, and polythiophene have been developed. A lithium secondary battery used for the positive electrode is being developed. The energy density of these batteries is said to be 40-80 Wh / kg. Recently, an organic disulfide compound has been proposed in US Pat. No. 4,833,048 as an organic material which can be expected to have a higher energy density. The compound is most easily is ^{M + - - S-R-} S - -M + and represented by (R is an aliphatic or aromatic organic group, S is sulfur, M ⁺ is a proton or a metal cation). This compound via an S-S bond linked to each other by electrolytic ^{oxidation, M + - - S-R} -S-S-R-S-S-R-S - polymer in the form such as -M ⁺ To do. The polymer thus produced returns to the original monomer by electrolytic reduction. A metal-sulfur secondary battery in which a metal M that supplies and captures a cation (M ⁺ ) and an organic disulfide compound is combined is proposed in the above-mentioned US patent. This battery is 150 Wh / k
An energy density comparable to or higher than that of an ordinary secondary battery can be expected to be g or more.

[0003]

However, the proposed disulfide compound is easy to move in the state of a monomer and is dissipated to the separator or the electrolyte from the positive electrode, and further to the negative electrode side. It had the drawback of a short discharge cycle life. The present invention provides a polymer electrode which solves such a problem, does not impair the feature of the organic disulfide compound having high energy density, and maintains high charge / discharge efficiency and can obtain good charge / discharge cycle characteristics. It is intended.

[0004]

The polymer electrode of the present invention comprises a layer containing an organic disulfide compound, a metal oxide and a π electron sharing conductive polymer (hereinafter referred to as SSCPML), and a π electron sharing conductive polymer. Is a polymer electrode in which layers mainly composed of (hereinafter, referred to as CPL) are alternately laminated, and the uppermost and lowermost portions are formed of CPL. Here, with an organic disulfide compound, the sulfur-sulfur bond is cleaved by electrolytic reduction to form a sulfur-metal ion (including proton) bond, and the sulfur-metal ion bond is converted to the original sulfur-sulfur bond by electrolytic oxidation. A compound that regenerates. In addition, in the method for producing a polymer electrode of the present invention, a metal oxide powder is mixed with a liquid obtained by dissolving an organic disulfide compound and a π-electron shared conductive polymer in N-alkyl-2-pyrrolidone, and the mixture is applied. CSP is formed by forming SSCPML and applying a liquid in which a π-electron sharing conductive polymer is dissolved in N-alkyl-2-pyrrolidone. The lithium secondary battery of the present invention uses the polymer electrode as a positive electrode.

[0005]

[Function] The monomer anion of the organic disulfide compound in SSCPML produced by the reduction diffuses and moves from SSCPML to CPL, but in CPL, C
It is trapped as an anion dopant of the π-electron shared conductive polymer in PL, and diffusion transfer to the outside of the electrode is effectively blocked. Therefore, high charge / discharge efficiency and excellent charge / discharge cycle life can be provided. In the method for producing a polymer electrode of the present invention, the organic disulfide compound or the π-electron sharing conductive polymer is uniformly and highly concentrated in N
-Alkyl-2-pyrrolidone is dissolved and the solution thus prepared is applied in multiple layers, so that it is possible to obtain a high-density and uniform pinhole-free multilayer coating film.

[0006]

EXAMPLES As the organic disulfide compound used in the present invention, a compound represented by the general formula (R (S) _y ) _n can be used. R is an aliphatic group or an aromatic group, S is sulfur, y is an integer of 1 or more, and n is an integer of 2 or more. H
Dithioglycol represented by SCH ₂ CH ₂ SH, C ₂ N ₂
2,5-dimercapto-1, represented by S (SH) ₂ ,
3,4-thiadiazole is represented by _{C 3 H 3 N 3 S 3} s-
Triazine-2,4,6 _{Torichioru, C 6 H 6 N 4 S} 3
7-methyl-2,6,8-trimercaptopurine represented by or 4,5-diamino-2,6-dimercaptopyrimidine represented by C ₄ H ₆ N ₄ S ₂ is used.
In each case, a commercial product can be used as it is. Further, it is possible to use a polymer of an organic disulfide compound obtained by polymerizing these organic disulfide compounds by a chemical polymerization method using an oxidizing agent such as iodine, potassium ferricyanide or hydrogen peroxide, or by an electrolytic oxidation method. In order to more effectively suppress the diffusion transfer of the organic disulfide compound at the time of assembling the battery, it is preferable to assemble the battery using a polymer such as a dimer or tetramer of the organic disulfide.

Since the organic disulfide compound and this polymer are electrically insulating, it is preferable to add a conductive substance when the SSCPML layer becomes thick and exceeds 50 μm. A carbon material such as acetylene black, artificial graphite, or natural graphite is used as such a conductive substance. In addition, a composite of the above conductive materials,
Alternatively, it is also possible to use a composite of the above conductive material with a polyolefin such as polypropylene or polybutene, a fluororesin such as polytetrafluoroethylene, or a synthetic resin material such as synthetic rubber. As the metal oxide, any of transition metal oxides and composite oxides can be used, but a compound having an electrochemical equivalent of polyaniline of 150 mAh / g or higher is particularly preferable. As such a transition metal oxide, LiCoO ₂ (electrochemical equivalent = 1
_{40~160mAh / g), V 6 O} 13 ( electrochemical equivalent =
160 to 230 mAh / g), LiMn ₂ O ₄ (electrochemical equivalent = 100 to 120 mAh / g), V ₂ O ₅ (electrochemical equivalent = 130 to 150 mAh / g), LiNiO ₂ (electrochemical equivalent = 140 to 220 mAh / g) g) is preferred.
A powdery material having an average particle size of about 1 to 10 μm is used. These transition metal oxides can be used without any trouble even if the transition metal elements are plural. For example, for LiCoO ₂ , Co (cobalt)
Part of Mn (manganese), Ni (nickel), Fe
A complex oxide in which (iron) is replaced or a complex oxide in which a part of V in V ₆ O ₁₃ is replaced by W (tungsten) can also be used.

Further, the metal cation M is contained in SSCPML.
An electrolyte containing ⁺ may be added. As such an electrolyte, a solid or semi-solid polymer electrolyte in which the organic disulfide monomer is less likely to diffuse and move is preferable. LiClO ₄ , LiCF _{3 on} polyethylene oxide
LiClO ₄ , L in a polymer solid electrolyte in which a lithium salt such as SO ₃ or LiN (CF ₃ SO ₂ ) ₂ is dissolved, or a non-aqueous solvent such as propylene carbonate or ethylene carbonate.
iCF ₃ SO ₃ , LiBF ₄ , LiPF ₆ , LiN (CF ₃
A semi-solid polymer electrolyte obtained by gelling an electrolyte solution in which a lithium salt such as SO ₂ ) ₂ is dissolved with a polymer such as polyacrylonitrile, polyvinylidene fluoride or polyacrylic acid is effectively used. A liquid electrolyte in which the lithium salt of N-alkyl-2-pyrrolidone is dissolved in about 1 M may be added.

Polyaniline, polypyrrole, polythiophene and the like can be used as the π electron sharing conductive polymer used in the CPL of the present invention. Preformed into a film by electrolytic polymerization method, preformed into a film by coating and drying a corresponding polymer solution, SS
What was formed on CPML by the electrolytic polymerization method, or what was formed by apply | coating and drying the corresponding polymer solution on SSCPML can be used. In particular, the reductive polyaniline in the undoped state is preferable because it effectively captures the organic disulfide monomer. The degree of reduction (RDI) of polyaniline is such that polyaniline is N-methyl-2-
It can be expressed based on the electronic absorption spectrum of a solution of a small amount dissolved in pyrrolidone. That is, the intensity of the absorption peak due to the para-substituted benzene structure appearing on the short wavelength side near 340 nm (I ₃₄₀ ) and the intensity of the absorption peak due to the quinone diimine structure appearing on the long wavelength side near 640 nm (I ₆₄₀ ). The ratio is represented by RDI = I ₆₄₀ / I ₃₄₀ . Polyaniline having an RDI of 0.5 or less is preferably used. The degree of dedoping of polyaniline is represented by conductivity. Polyaniline having a conductivity of 10 ⁻⁵ S / cm or less is preferably used.

As the N-alkyl-2-pyrrolidone used in the method for producing the polymer electrode of the present invention, commercially available reagents may be used as they are, or water content may be adjusted to 20 by using a zeolite adsorbent.
It is possible to use those reduced to ppm or less. Pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2
-Pyrrolidone, N-butyl-2-pyrrolidone and the like can be used. Further, a vinylpyridine copolymer (hereinafter referred to as PV) is added to one or both of SSCML and CPL.
Referred to as P) can be added. By adding PVP, the bonding between SSCPML and CPL can be improved, the mechanical strength of the entire electrode can be increased, and the polarization can be reduced.
Such a vinyl pyridine copolymer has a solubility of 10 wt% or more in N-alkyl-2-pyrrolidone and shows almost no solubility in an aprotic solvent such as propylene carbonate or ethylene carbonate. Is preferred. As the copolymerization main component, 4-vinylylpyridine or quaternized 4-vinylpyridine is preferable. As such a copolymer of vinylpyridine, there is "MH-1" manufactured by Koei Chemical Industry Co., Ltd. As the other copolymerization component copolymerized with vinylpyridine, any polymerizable vinyl compound can be used. Examples of such vinyl compounds include (meth) acrylic acid or esters thereof, vinyl chloride, acrylonitrile, vinyl acetate, and styrene. Particularly, (meth) acrylic acid hydroxy ester such as hydroxyethyl (meth) acrylate or hydroxybutyl (meth) acrylate having a hydroxyl group is preferable. The copolymerization ratio is preferably 50% or more in terms of molar ratio of vinylpyridine.

As the metal ion used when the organic disulfide compound is reduced to form a salt, a proton can be used in addition to the alkali metal ion and alkaline earth metal ion described in the above-mentioned US patent. When lithium ions are used as the alkali metal ions, metal lithium or a lithium alloy such as lithium-aluminum is used as an electrode that supplies and captures the lithium ions, and an electrolyte that conducts the lithium ions is used. A battery can be constructed. Using protons,
LaNi ₅ as an electrode for supplying and trapping protons
A battery having a voltage of 1 to 2 volt can be formed by using a metal hydride such as ## STR3 ## and an electrolyte that conducts protons.

[0012] [Example 1] [pi manufactured by Nitto Denko Corporation of polyaniline as an electronic covalent conductive polymer (trade name Anirido) dedoped in an alkaline solution, the conductivity obtained by reduction with hydrazine is 10 ^{@ 8} S / A dedoped reduced polyaniline powder having a cm and RDI value of 0.3 was used. 0.5 g of this dedoped polyaniline powder was dissolved in 20 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) to give blue PAn-N.
An MP solution (CP1-1) was obtained. On the other hand, 2,5-dimercapto-1,3,4-thiadiazole (hereinafter referred to as DMcT) monomer powder is used as the organic disulfide compound. 2 g of this DMcT monomer powder and 1 g of the above-mentioned dedoped polyaniline powder were dissolved in 5 g of NMP,
A viscous DMcT-PAn-NMP solution was obtained. Further, 2.5 g of V ₆ O ₁₃ powder having an average particle diameter of 6 μm was added to 10 g of NMP in which 5% of a 60:40 (molar ratio) copolymer of 4-vinylpyridine as a vinyl pyridine copolymer and hydroxymethyl methacrylate was dissolved. The mixture was dispersed and mixed to obtain a slurry. This slurry was added to the DMcT-PAN-NM
The mixture was added to and mixed with the P viscous solution, and then mixed with a homogenizer at a rotation speed of 5000 rpm for about 10 minutes to obtain a dispersion liquid. A part of NMP was removed from this dispersion with a rotary evaporator to obtain a viscous dispersion (SSCPM1-1).

Next, 90% of CP1-1 was applied onto a carbon film 1 having a thickness of 40 μm made of fibrous fluororesin and carbon black bonded to a titanium foil 2 having a thickness of 30 μm.
It is applied to a thickness of μm and heated in an Ar gas stream at 80 ° C. for 15 minutes and then at a reduced pressure of 1 cmHg for 80 minutes.
A heat treatment was carried out at a temperature of ℃ to form a polyaniline film 3a having a thickness of 3 μm. Next, SSCPM is formed on the polyaniline film 3a.
1-1 was applied to a thickness of 120 μm, heated at 80 ° C. for 15 minutes in an Ar gas stream, and then heat-treated at 80 ° C. under a reduced pressure of 1 cmHg to form a 15 μm-thick organic disulfide + V ₆ O ₁₃ + PAn film. 4a was formed. Further, CP1-1 was applied on the film 4a to a thickness of 90 μm,
After heating at 80 ° C for 15 minutes in Ar gas stream,
Heat treatment was performed at 80 ° C. under a reduced pressure of 1 cmHg to form a polyaniline film 3b having a thickness of 3 μm. After that, the steps of forming the organic disulfide + V ₆ O ₁₃ + PAn film and the polyaniline film are alternately repeated twice to form films 4b, 3c,
4c and 3d were formed to obtain a multilayer film having a cross-sectional structure as shown in FIG. The obtained membrane was cut into a 2 × 2 cm square to obtain a polymer electrode A.

[Comparative Example 1] CPl-1 used in Example 1
Was coated on a carbon film 5 bonded to a titanium foil 6 having the same structure as in Example 1 to form a film 7a made of dedoped reducing polyaniline, and then SSCPM1-1 used in Example 1 was also formed into a film. A film 8a made of organic disulfide + V ₆ O ₁₃ + PAn was formed by coating on 7a. The step of forming the organic disulfide + V ₆ O ₁₃ + PAn film was repeated twice more to form films 8b and 8c, and a multilayer film having a cross-sectional structure as shown in FIG. 2 was obtained. The obtained film was cut into a 2 × 2 cm square to obtain a polymer electrode B.

[0015] [Example 2] [pi manufactured by Nitto Denko Corporation of polyaniline as an electronic covalent conductive polymer (trade name Anirido) dedoped in an alkaline solution, the conductivity obtained by reduction with hydrazine is 10 ^{@ 8} S / cm and RDI value of 0.34, 0.5 g of dedoped reduced polyaniline powder was dissolved in 20 g of NMP to obtain a blue PAn-NMP solution (CP1-2).
2 g of 4,5-diamino-2,6-dimercaptopyrimidine (hereinafter referred to as DDPy) monomer powder and 1 g of the above-mentioned dedoped polyaniline powder were dissolved in 5 g of NMP to obtain a viscous DDPy-PAn-NMP solution. . 2.5 g of V ₂ O ₅ powder having an average particle size of 3.5 μm was added to N
MP10g was dispersed and mixed to obtain a slurry. This slurry was added to and mixed with a DDPy-PAn-NMP viscous solution, and then a homogenizer was operated at a rotation speed of 5000 rpm for about 10 minutes.
Minute mixing was performed to obtain a dispersion liquid. A part of NMP was removed from this dispersion with a rotary evaporator to obtain a viscous dispersion (SSCPM1-2).

First, 90 parts of CP1-2 are formed on a carbon film 1 having a thickness of 40 μm and made of fibrous fluororesin and carbon black bonded to a titanium foil 2 having a thickness of 30 μm.
It is applied to a thickness of μm and heated in an Ar gas stream at 80 ° C. for 15 minutes and then at a reduced pressure of 1 cmHg for 80 minutes.
A heat treatment was carried out at a temperature of ℃ to form a polyaniline film 3a having a thickness of 3 μm. Next, 120 μm of SSCPM1-2 on the film 3a.
It is applied at a thickness of 80 m in Ar gas stream at 1
After heating for 5 minutes, depressurize at 1 cmHg at 80 ℃
Heat-treated with 12 μm thick organic disulfide + V ₂
The O ₅ + PAn film 4a was formed. Furthermore, C on the film 4a
Pl-2 was applied to a thickness of 90 μm, heated at 80 ° C. for 15 minutes in an Ar gas stream, and then heat-treated at 80 ° C. under a reduced pressure of 1 cmHg to form a polyaniline film 3b having a thickness of 3 μm. After this, organic disulfide +
The steps of forming the V ₂ O ₅ + PAn film and the polyaniline film were alternately repeated twice to form films 4b, 3c, 4c and 3d, and a multilayer film having a cross-sectional structure as shown in FIG. 1 was obtained. The obtained film was cut into a 2 × 2 cm square to obtain a polymer electrode C.

[Comparative Example 2] CP1-2 used in Example 2
Was applied onto the carbon film 5 to form a film 7a made of dedoped reducing polyaniline, and then the same procedure as in Example 2 was performed.
The SSCPM1-2 used in 1) was applied on the film 7a to form a film 8a made of organic disulfide + V ₂ O ₅ + PAn.
The step of forming the organic disulfide + V ₂ O ₅ + PAn film was repeated twice more to form films 8b and 8c, and a multilayer film having a cross-sectional structure as shown in FIG. 2 was obtained. The obtained film was cut into a 2 × 2 cm square to obtain a polymer electrode D.

[0018] [Example 3] [pi as an electronic covalent conductive polymer, manufactured by Nitto Denko polyaniline (trade name Anirido) dedoped in an alkaline solution, the conductivity obtained by reduction with hydrazine is 10 ^{@ 8} S / Cm, RDI value of 0.28 dedoped reduced polyaniline powder is used. Further, a DMcT polymer powder obtained by chemically oxidizing the DMcT monomer with iodine in an aqueous lithium hydroxide solution was prepared. On the other hand, 5% by weight of linear polyethylene oxide (PEO-1, manufactured by Sumitomo Seika, average molecular weight = 140,000) and lithium perchlorate (LiClO ₄ ) were dissolved in NEP at 1 mol / liter. 1.0 g of the above-mentioned dedoped reduced polyaniline powder and 2 g of DMcT polymer powder were dissolved in 10 g of this NEP to obtain a viscous DMcT-PAn-NEP-PEO viscous solution. V ₂ O _{5 with} an average particle size of 3.5 μm
2.5 g of the powder was dispersed and mixed in 10 g of NEP to obtain a slurry. This slurry was added to the above DMcT-PAn-NEP.
-After adding and mixing to the PEO viscous solution, a homogenizer was mixed at a rotation speed of 5000 rpm for about 10 minutes to obtain a dispersion liquid. A part of NEP was removed with a rotary evaporator to obtain a viscous dispersion liquid (SSCPMl-3). Further, 0.5 g of the same undoped reduced polyaniline powder was added to N
Dissolve in 20 g of MP, blue PAn-NEP solution (CP
1-3 was obtained.

First, 90 parts of CPl-3 are formed on a carbon film 1 having a thickness of 40 μm, which is made of fibrous fluororesin and carbon black bonded to a titanium foil 2 having a thickness of 30 μm.
It is applied to a thickness of μm and heated in an Ar gas stream at 80 ° C. for 15 minutes and then at a reduced pressure of 1 cmHg for 80 minutes.
A heat treatment was carried out at a temperature of ℃ to form a polyaniline film 3a having a thickness of 3 μm. Next, on the polyaniline film 3a, SSCPM1-
3 was applied to a thickness of 90 μm, heated at 80 ° C. for 15 minutes in an Ar gas stream, and then heat-treated at 80 ° C. under a reduced pressure of 1 cmHg to form an organic disulfide / polyaniline / V ₂ O ₅ / thickness of 15 μm. A polyethylene oxide polymer electrolyte composite membrane 4a was formed. Further, CPl-3 was applied on the composite film 4a to a thickness of 90 μm, heated in an Ar gas stream at 80 ° C. for 15 minutes, and then 1 cm.
Heat treatment at 80 ℃ under reduced pressure of Hg, thickness 3μm
The polyaniline film 3b was formed. Thereafter, the steps of forming the organic disulfide / polyaniline / V ₂ O ₅ / polyethylene oxide polymer electrolyte composite film and the polyaniline film are alternately repeated twice to form the films 4b, 3c, 4c, 3d.
Was formed. The obtained film was cut into a 2 × 2 cm square to obtain a polymer electrode E.

[Comparative Example 3] CPl-3 used in Example 3
Was coated on a carbon film to form a film 7a made of dedoped reducing polyaniline, and then SSCPMl-3 used in Example 3 was also coated on the film 7a to form organic disulfide, polyaniline, V ₂ O ₅ and polyethylene. A film 8a containing an oxide polymer electrolyte was formed. The steps of forming a film containing an organic disulfide, polyaniline, V ₂ O ₅ and a polyethylene oxide polymer electrolyte were repeated twice more to form films 8b and 8c. The obtained film was cut into a 2 × 2 cm square to obtain a polymer electrode F.

The electrodes A obtained in the above-mentioned Examples and Comparative Examples,
B, C, D, E, and F are used as positive electrodes, metal lithium having a thickness of 0.3 mm is used as a negative electrode, and a gel electrolyte having a thickness of 0.6 mm is used as a separator layer. D, E, and F were constructed. The gel electrolyte was prepared by adding 3.0 g of polyacrylonitrile to LiBF4
Is gelled with 20.7 g of a propylene carbonate / ethylene carbonate (1: 1 volume ratio) solution in which 1M was dissolved. These batteries were stored at 20 ° C for 0 days, 5 days.
After storage for 46 days on a constant current of 0.2 mA, 4.5 ~
The charge / discharge cycle was repeated in the range of 1.5 V, the discharge capacity (Q, unit: mAh) in each charge / discharge cycle was measured, and the electrode storage performance was evaluated by the reduction amount of the discharge capacity due to storage of the battery. The results are shown in Tables 1 to 3. As is clear from the above results, the batteries using the electrodes A, C, and E of Examples 1, 2, and 3 according to the present invention used the electrodes B, D, and F of the corresponding comparative examples, respectively. Compared to batteries, the decrease in discharge capacity during battery storage and charge / discharge cycles is small.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

EFFECT OF THE INVENTION The electrode of the present invention is provided with a π-electron sharing conductive polymer layer on the upper and lower sides, and a layer containing an organic disulfide compound, a π-electron sharing conductive polymer and a metal oxide, and a π-electron sharing conductive polymer layer. Since it has a structure in which molecular layers are alternately stacked, dissipation of the organic disulfide compound monomer from the electrode is reduced during battery storage and charge / discharge. Therefore, by using this electrode, it is possible to obtain a high energy density secondary battery with little decrease in discharge capacity after storage and during charge / discharge. In the examples, only the example in which the polymer electrode was applied to the battery was shown, but in addition to the battery, by using the polymer electrode of the present invention as a counter electrode, an electrochromic element having a high coloring / fading speed and a high response speed. A biochemical sensor such as a fast glucose sensor can be obtained, and an electrochemical analog memory with a high writing / reading speed can be constructed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a polymer electrode according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a polymer electrode of a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrode current collector consisting of carbon film 2 Titanium foil 3a to 3d Layer mainly composed of π electron sharing conductive polymer 4a to 4c Layer containing organic disulfide compound, π electron sharing conductive polymer and metal oxide

Claims (6)

[Claims] 1. A sulfur-sulfur bond is cleaved by electrolytic reduction to form a sulfur-metal ion (including proton) bond,
A layer containing an organic disulfide compound whose sulfur-metal ionic bond regenerates the original sulfur-sulfur bond by electrolytic oxidation, a layer containing a metal oxide and a π-electron shared conductive polymer, and a π-electron shared conductive polymer A polymer electrode having a layered structure in which layers are alternately stacked, and the uppermost and lowermost layers are layers mainly composed of a π-electron sharing conductive polymer. 2. The polymer electrode according to claim 1, wherein the layer containing the organic disulfide compound, the metal oxide, and the π-electron sharing conductive polymer contains an electrolyte. 3. The polymer electrode according to claim 1, wherein the π-electron sharing conductive polymer is polyaniline in a dedoped / reduced state. 4. A step of applying a solution prepared by dissolving a π-electron sharing conductive polymer in N-alkyl-2-pyrrolidone onto a substrate to form a coating film, dissolving an organic disulfide compound and a π-electron sharing conductive polymer in an alkylpyrrolidone. A step of forming a layered coating film by alternately applying a mixture of the liquid and the metal oxide powder, and a liquid obtained by dissolving a π-electron shared conductive polymer in N-alkyl-2-pyrrolidone on the coating film,
And a step of forming a coating film by applying a liquid in which a π-electron shared conductive polymer is dissolved in N-alkyl-2-pyrrolidone onto the layered coating film to form a coating film. 5. The method for producing a polymer electrode according to claim 4, wherein the π-electron sharing conductive polymer is polyaniline in a dedoped / reduced state. 6. A lithium secondary battery comprising the polymer electrode according to claim 1 as a positive electrode.