JP2012221886A - Power storage device, and method for manufacturing negative electrode for power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new power storage device using anions as carriers.SOLUTION: A power storage device in accordance with an embodiment of the present invention comprises a positive electrode, a negative electrode containing a hardly-soluble nitrogen-containing organic material obtained by reducing the solubility of a nitrogen-containing organic polymer and doped with anions, and an ion conducting medium intervening between the positive electrode and the negative electrode and conducting anions, and is charged and discharged by migration of anions. The negative electrode is made from the nitrogen-containing organic polymer by the successive steps of heating a material containing the nitrogen-containing organic polymer to reduce the solubility, doping the nitrogen-containing organic polymer or a material derived from the nitrogen-containing organic polymer with anions, and forming the negative electrode on a collector by mixing the nitrogen-containing organic polymer or the material derived from the nitrogen-containing organic polymer and a binder. The heating may be performed at temperatures equal to or higher than 100°C and equal to or lower than 500°C to reduce the solubility.

Description

  The present invention relates to a power storage device and a method for manufacturing a negative electrode for a power storage device.

Conventionally, as an electricity storage device, a secondary electrochemical cell using an anion charge carrier that can be accommodated by a positive electrode and a negative electrode containing an anion host material, CF as a positive electrode, a metal such as La as a negative electrode, and F ⁻ as an anion. The one to be used has been proposed (see, for example, Patent Document 1).

Special table 2009-529222

  However, in the electricity storage device of Patent Document 1 described above, an anion-supporting material is used for the positive electrode and a metal is used for the negative electrode, discharge is the negative electrode, and charging is a battery system in which a chemical reaction proceeds at the positive electrode. Therefore, problems may occur in cycle characteristics and rate characteristics, and the development of new power storage devices has been desired.

  This invention is made | formed in view of such a subject, and it aims at providing the manufacturing method of the novel electrical storage device which uses an anion as a carrier, and the negative electrode for electrical storage devices.

  As a result of diligent research to achieve the above-described object, the present inventors can charge and discharge using an anion as a carrier when the nitrogen-containing organic polymer is made slightly soluble and an anion is doped and used for the negative electrode. As a result, the present invention has been completed.

  That is, the electricity storage device of the present invention includes a positive electrode, a negative electrode containing a nitrogen-containing organic poorly soluble material doped with an anion and made the nitrogen-containing organic polymer hardly soluble, and the anion interposed between the positive electrode and the negative electrode. An ionic conductive medium that conducts and charges and discharges by movement of the anion.

  The method for producing a negative electrode for an electricity storage device according to the present invention comprises using a nitrogen-containing organic polymer as a raw material, a heat treatment as a sparing treatment for heating a substance containing the nitrogen-containing organic polymer, the nitrogen-containing organic polymer, or the nitrogen-containing organic polymer. A negative electrode is formed by performing a doping process of doping an anion to a substance derived from the material, a forming process of mixing the nitrogen-containing organic polymer or the substance derived from the nitrogen-containing organic polymer and a binder and forming the mixture on a current collector in a predetermined order. Manufacturing step.

  The method for producing an electricity storage device and an anode for an electricity storage device of the present invention can be charged and discharged using an anion as a carrier. The reason why such an effect is obtained is not clear, but is presumed as follows. For example, in a power storage device in which a carbon material is used for the positive electrode and polyaniline is used for the negative electrode to produce a nitrogen-containing organic poorly soluble product, the negative electrode reaction is represented by the following formula (1), and the positive electrode reaction is represented by the following formula (2). be able to. In charging, the anion supported on the negative electrode moves to the positive electrode, and in discharging, the anion held on the positive electrode moves again to the negative electrode. As described above, it is presumed that the anion as a carrier moves and acts as an electricity storage device. And since the nitrogen-containing organic polymer is hardly solubilized, elution of the nitrogen-containing organic polymer into the electrolytic solution during power storage is suppressed, and it is presumed that the power storage performance can be exhibited sufficiently easily.

The schematic diagram which shows the operation | movement principle of the electrical storage device of this invention. IR spectrum of polyaniline and black powder after heating. IR spectrum of polyaniline after heat treatment before and after anion doping treatment. The EDX measurement result of the nitrogen-containing organic poorly soluble material after anion doping. 2 is a charge / discharge curve of the electricity storage device of Example 1. FIG. IR spectrum of polyaniline before and after heat treatment after anion doping. Charging / discharging curve of the electricity storage device of Example 2 Changes over time in battery capacity and charge / discharge efficiency in 30 cycles at an upper limit potential of 4.2 V. IR spectra before and after heat treatment of the negative electrode mixture. 10 is a charge / discharge curve of the electricity storage device of Example 3. The production scheme of each sample of Examples 1-3. The XPS measurement result with respect to B, N, and F of each sample of Examples 1-3.

  The electricity storage device of the present invention includes a positive electrode, a negative electrode containing a nitrogen-containing organic poorly soluble material doped with an anion and made a nitrogen-containing organic polymer slightly soluble, and an ion conductive medium that is interposed between the positive electrode and the negative electrode to conduct the anion. And charging and discharging by movement of anions. FIG. 1 is a schematic view showing the operating principle of the electricity storage device of the present invention. In FIG. 1, a carbon material is used for the positive electrode, and the cation is represented as A and the anion is represented as B. In this electricity storage device, anions are occluded in the negative electrode during discharging, and anions are released from the negative electrode during charging. Specifically, for example, an anion binds to the nitrogen site of the nitrogen-containing organic poorly soluble product during discharge and the negative electrode active material is oxidized, and during charging, the anion is desorbed from the nitrogen-containing organic poorly soluble product nitrogen site and the negative electrode It is thought that the active material is reduced. At this time, a reserve-type reaction may be generated, or a capacitance due to the electric double layer may be generated. In this electricity storage device, it is considered that anions are released from the positive electrode during discharging and occluded in the positive electrode during charging.

  In the electricity storage device of the present invention, the positive electrode is prepared by, for example, mixing a positive electrode active material, a conductive material, and a binder, and adding a suitable solvent to form a paste-like positive electrode material on the surface of the current collector. However, it may be compressed to increase the electrode density as necessary. The positive electrode active material is not particularly limited as long as it can occlude and release anions, and examples thereof include carbon materials and metal oxides. Examples of the carbon material include graphite, carbon black, activated carbon, and the like, and those containing graphite as a main component are preferable. Here, “having graphite as a main component” means that graphite is contained in an amount of 50% or more, preferably 90% or more, more preferably 95% or more. If it is such, it may contain amorphous carbon and may contain other active materials. Examples of graphite include natural graphite (scale-like graphite, scale-like graphite), artificial graphite, and the like, but artificial graphite is preferable in that the potential of the electricity storage device can be further increased and the energy density can be increased. . Furthermore, it is preferable to use artificial graphite activated with alkali, since the interlayer of graphite expands and ions easily enter and exit, and output characteristics are improved. Specifically, alkali activation can be performed by adding an alkali such as Na or K to graphite and treating the graphite at a high temperature of 600 ° C. to 1000 ° C. in an inert atmosphere. Use of a carbon material as the positive electrode active material is preferable because it easily absorbs and releases anions reversibly.

  The conductive material is not particularly limited as long as it is an electron conductive material that does not adversely affect the electrode performance. A mixture of one or more of black, carbon whisker, needle coke, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) can be used. Among these, as the conductive material, carbon black and acetylene black are preferable from the viewpoints of electron conductivity and coatability. The binder serves to bind the active material particles and the conductive material particles. For example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluorine-containing resin such as fluorine rubber, or polypropylene, Thermoplastic resins such as polyethylene, ethylene-propylene-dienemer (EPDM), sulfonated EPDM, natural butyl rubber (NBR) and the like can be used alone or as a mixture of two or more. Examples of the solvent for dispersing the active material, the conductive material, and the binder include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, and N, N-dimethylaminopropylamine. Organic solvents such as ethylene oxide and tetrahydrofuran can be used. Moreover, a dispersing agent, a thickener, etc. may be added to water, and an active material may be slurried with latex, such as SBR. As the thickener, for example, polysaccharides such as carboxymethyl cellulose and methyl cellulose can be used alone or as a mixture of two or more. Examples of the application method include roller coating such as applicator roll, screen coating, doctor blade method, spin coating, bar coater, and the like, and any of these can be used to obtain an arbitrary thickness and shape. Current collectors of the positive electrode include aluminum, titanium, stainless steel, nickel, iron, calcined carbon, conductive polymer, conductive glass, etc., as well as aluminum and titanium for the purpose of improving adhesion, conductivity and oxidation resistance. What processed the surface of copper etc. with carbon, nickel, titanium, silver, etc. can be used. For these, the surface can be oxidized. Examples of the shape of the current collector include foil, film, sheet, net, punched or expanded, lath, porous, foam, and formed fiber group. The thickness of the current collector is, for example, 1 to 500 μm.

In the electricity storage device of the present invention, the negative electrode is, for example, a mixture of a negative electrode active material, a conductive material, and a binder, and an appropriate solvent is added to form a paste electrode mixture on the surface of the current collector. It may be dried and compressed to increase the electrode density as necessary. The negative electrode active material includes a nitrogen-containing organic hardly-solubilized material that is doped with an anion and hardly dissolves the nitrogen-containing organic polymer. The nitrogen-containing organic polymer is not particularly limited as long as it contains nitrogen in the material, and examples thereof include polyaniline, polypyrrole, polypyridine, polyethyleneimine, and the like. Is preferred. The molecular weight of the organic polymer is not particularly limited, but is preferably in the range of 2,000 to 100,000. The kind of the doped anion is not particularly limited, and examples thereof include halogen, chalcogen, tetrafluoroboric acid, hexafluorophosphoric acid, trifluoromethanesulfonic acid, bis (trifluoromethanesulfonic acid) imide, etc. From the viewpoint of mobility during charging and discharging, tetrafluoroboric acid (BF ₄ ⁻ ) is more preferable. The sparingly soluble method is not particularly limited as long as the solubility of the nitrogen-containing organic polymer in the solvent can be reduced. Examples thereof include thermal decomposition by heat treatment of the polymer and condensation by a crosslinking agent. Is more preferable. Since the electrode may be subjected to a heating process such as drying, it can be performed as a process common to this process. This heat treatment may be performed in a temperature range of 100 ° C. or more and 500 ° C. or less, for example.

  As the conductive material, binder, solvent and the like used for the negative electrode, those exemplified for the positive electrode can be used. The negative electrode current collector includes copper, nickel, stainless steel, titanium, aluminum, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc., as well as improved adhesion, conductivity and reduction resistance. For the purpose, for example, a copper surface treated with carbon, nickel, titanium, silver or the like can be used. For these, the surface can be oxidized. The shape of the current collector can be the same as that of the positive electrode.

  As the ionic conduction medium of the electricity storage device of the present invention, those capable of conducting anions can be used, and non-aqueous electrolytes and non-aqueous gel electrolytes containing a supporting salt can be used. The This ion conductive medium may contain an organic solvent such as an ionic liquid or a carbonate, and preferably contains an anion of the same kind as that doped with a nitrogen-containing organic poorly soluble material contained in the negative electrode active material. If a carbonate-based organic solvent is included, freezing at a low temperature can be prevented, and low-temperature characteristics such as output characteristics at a low temperature can be improved. In addition, if a carbonate-based organic solvent is added, the viscosity can be reduced to improve the output characteristics. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, vinylene carbonate, butylene carbonate, and chloroethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl-n-butyl carbonate, and methyl-t-. Chain carbonates such as butyl carbonate, di-i-propyl carbonate, t-butyl-i-propyl carbonate, cyclic esters such as γ-butyllactone and γ-valerolactone, methyl formate, methyl acetate, ethyl acetate, butyric acid Chain esters such as methyl, ethers such as dimethoxyethane, ethoxymethoxyethane and diethoxyethane, nitriles such as acetonitrile and benzonitrile, tetrahydrofuran, Examples include furans such as methyltetrahydrofuran, sulfolanes such as sulfolane and tetramethylsulfolane, and dioxolanes such as 1,3-dioxolane and methyldioxolane. Among these, the combination of cyclic carbonates and chain carbonates is preferable.

The ionic liquid is a salt of a cation and an anion melted at room temperature, and examples of the cation include imidazolium, ammonium, choline, pyridinium, piperidinium and the like. Examples of imidazolium include 1- (hydroxyethyl) -3-methylimidazolium and 1-methyl-3-octylimidazolium, and examples of ammonium include N, N-dimethylammonium and tetrabutylammonium. Examples of pyridinium include 1-butyl-3-methylpyridinium and 1-butylpyridinium, and examples of piperidinium include 1-ethyl-1-methylpiperidinium. As the anion, TFSI ^- and BETI ^- other imide anion, such _{^{as, BF 4 -, ClO 4 -}} , PF 6 -, Br -, Cl -, F - inorganic anions and the like. Among these, if the anion is tetrafluoroborate, the power storage device can be further reduced in weight. If the anion is TFSI ⁻ , the charge / discharge characteristics can be further enhanced. Specific examples of the anion as BF ₄ ⁻ include diethylmethyl (2 methoxyethyl) ammonium and BF ₄ . Specific examples of the anion used as TFSI include N-methyl-N-propylpiperidinium bis (trifluoromethanesulfonyl) imide (abbreviation: PP13TFSI), 1-ethyl-3-methyl-imidazolium bis (trifluoro) (Romethanesulfonyl) imide (abbreviation: EMITFSI), N, N, N-trimethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide (abbreviation: TMPATFSI), N, N-diethyl-N-methyl-N- (2- And methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide. Of these, PP13TFSI is preferred. When the ionic liquid and the organic solvent are mixed and used, the concentration of the ionic liquid is preferably 0.5 M or more and 2.0 M or less.

The supporting salt contained in the electricity storage device of the present invention is, for example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiSbF _6. , LiSiF ₆ , LiAlF ₄ , LiSCN, LiClO ₄ , LiCl, LiF, LiBr, LiI, LiAlCl _{4 and the} like. Among these, from the group consisting of inorganic salts such as LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , and organic salts such as LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) _3. It is preferable from the viewpoint of electrical characteristics to use a combination of one or two or more selected salts. This electrolyte salt preferably has a concentration in the non-aqueous electrolyte of 0.1 mol / L or more and 5 mol / L or less, and more preferably 0.5 mol / L or more and 2 mol / L or less. When the concentration of the electrolyte salt is 0.1 mol / L or more, a sufficient current density can be obtained, and when the concentration is 5 mol / L or less, the electrolytic solution can be made more stable. Moreover, you may add flame retardants, such as a phosphorus type and a halogen type, to this non-aqueous electrolyte.

The electricity storage device 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 it is a composition that can withstand the use range of the electricity storage device. For example, glass fiber glass filters, polypropylene nonwoven fabrics, polymer nonwoven fabrics such as polyphenylene sulfide nonwoven fabrics, polyethylene and polypropylene, etc. A thin microporous film of an olefin resin can be mentioned. Among these, a glass filter has good wettability with an electrolytic solution such as a BF ₄ -based ionic liquid, and can smoothly move the anion. These may be used alone or in combination.

  The shape of the electricity storage device 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 square type. Moreover, you may apply to the large sized thing etc. which are used for an electric vehicle etc.

  Next, a method for manufacturing the electricity storage device will be described. The negative electrode of this electricity storage device uses a nitrogen-containing organic polymer as a raw material, and heat treatment as a sparing treatment for heating a substance containing a nitrogen-containing organic polymer, a nitrogen-containing organic polymer or a substance derived from a nitrogen-containing organic polymer is doped with an anion A negative electrode manufacturing step in which a doping process, a forming process in which a nitrogen-containing organic polymer or a substance derived from a nitrogen-containing organic polymer and a binder are mixed and formed on a current collector are performed in a predetermined order.

  For example, in the negative electrode preparation process, a nitrogen-containing organic polymer is doped with an anion, and then an anion-doped nitrogen-containing organic polymer and a binder are mixed and formed on the current collector. After that, heat treatment may be performed in which a substance containing a nitrogen-containing organic polymer formed on the current collector is heated. If it carries out like this, since a heating process is performed after forming an electrode compound material on a collector, it can be set as the heating process which served as the drying process. Examples of the nitrogen-containing organic polymer to be used include polyaniline, polypyrrole, polypyridine, polyethyleneimine, etc. Among them, polyaniline is preferably used. Examples of the anion to be doped include halogen, chalcogen, tetrafluoroboric acid, hexafluorophosphoric acid, trifluoromethanesulfonic acid, bis (trifluoromethanesulfonic acid) imide, etc. Among them, tetrafluoroboric acid is more preferable. The dope treatment can be performed, for example, by dispersing a nitrogen-containing organic polymer in an organic solvent, adding a compound containing an anionic component, and stirring. Examples of the organic solvent include acetone, alcohol, diethyl ether, and the like. Examples of the compound containing an anionic component include tetrafluoroboric acid diethyl ether complex. In the formation process, for example, a nitrogen-containing organic polymer after anion doping, a conductive material, and a binder are mixed, and an appropriate solvent is added to form a paste-like electrode mixture on the surface of the current collector It is good also as what to do. Note that as the conductive material, the binder, the solvent, and the current collector, those described for the electricity storage device can be used as appropriate. The heat treatment is desirably performed at a temperature at which the nitrogen-containing organic polymer is thermally decomposed and in a temperature range in consideration of the heat resistance of the material included in the electrode mixture. For example, it is preferably performed in the range of 100 ° C. or higher and 180 ° C. or lower, and more preferably in the range of 120 ° C. or higher and 160 ° C. or lower. The heating atmosphere may be, for example, air or an inert atmosphere such as a rare gas or nitrogen gas. If it carries out like this, the negative electrode containing the nitrogen-containing organic poorly soluble material which doped the anion which performed the poorly soluble process can be produced. Moreover, the temperature range of heat processing is lower and preferable. Furthermore, charge / discharge efficiency and charge / discharge capacity can be further increased.

  Alternatively, in the negative electrode preparation step, the nitrogen-containing organic polymer is doped with anions, then the anion-doped nitrogen-containing organic polymer is heated, and then the heat-treated nitrogen-containing organic polymer is derived. It is good also as what performs the formation process which mixes the substance and binder, and forms on a collector. At this time, the heat treatment is desirably performed at a temperature at which the nitrogen-containing organic polymer is thermally decomposed and in a temperature range in consideration of the heat resistant temperature of the doped anion. For example, it is preferably performed in the range of 100 ° C. or higher and 250 ° C. or lower, and more preferably performed in the range of 150 ° C. or higher and 200 ° C. or lower. Even in this case, a negative electrode containing a nitrogen-containing organic hardly soluble material doped with an anion subjected to poorly soluble treatment can be produced. In addition, you may employ | adopt the method mentioned above for other dope processing, formation processing, etc.

  Alternatively, in the negative electrode preparation step, a heat treatment is performed by heating a substance containing a nitrogen-containing organic polymer using a nitrogen-containing organic polymer as a raw material, and after performing a doping treatment in which a substance derived from the heated nitrogen-containing organic polymer is doped with an anion, It is good also as what performs the formation process which mixes the substance derived from the nitrogen-containing organic polymer which doped the anion, and a binder, and forms on a collector. At this time, the heat treatment is desirably performed at a temperature at which the nitrogen-containing organic polymer is thermally decomposed and at a temperature range in which the structure of the nitrogen-containing organic polymer is not destroyed. For example, it is preferably performed in the range of 100 ° C. or more and 500 ° C. or less, and more preferably in the range of 250 ° C. or more and 350 ° C. or less. Even in this case, a negative electrode containing a nitrogen-containing organic hardly soluble material doped with an anion subjected to poorly soluble treatment can be produced. In addition, you may employ | adopt the method mentioned above for other dope processing, formation processing, etc.

  In the electricity storage device of the present embodiment described in detail above, an anion is doped, and the nitrogen-containing organic poorly soluble product in which the nitrogen-containing organic polymer is hardly soluble is contained in the negative electrode, and can be charged and discharged by the movement of the anion. In addition, since the electricity storage device of the present invention is an electricity storage device using anions as carriers, the occurrence of a short circuit due to overload can be significantly reduced as compared with, for example, a Li ion battery. In addition, the power storage system is expected to have high output because it takes in and out anions in a capacitor-like manner. The capacity can be easily changed depending on the amount doped in the nitrogen-containing organic polymer and the anion used, and a high-capacity electricity storage device can also be constructed. Moreover, since all the electrodes comprised are stable in air | atmosphere, the manufacturing process is also very easy.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  Below, the example which produced the electrical storage device of this invention concretely is demonstrated as an Example.

[Example 1]
A polyaniline (average molecular weight 20000) was heat-treated at 300 ° C. for 1 hour to obtain a black powder. This black powder was hardly dispersed in most solvents (nitrogen-containing organic poorly soluble product). FIG. 2 is an IR spectrum of polyaniline and black powder after heating. FIG. 2 is an IR spectrum of polyaniline before heat treatment (upper) and polyaniline after heat treatment at 300 ° C. (lower). The IR spectrum was measured by the KBr method using an IR measuring device (Magna 760 type Fourier infrared spectrometer manufactured by Nicorey). From the IR spectrum shown in FIG. 2, it was suggested that complete carbonization did not occur and the partial structure of the original polyaniline was retained. Next, tetrafluoroboric acid diethyl ether complex was added to 100 mg of this heat-treated polyaniline in acetone, and the mixture was stirred at room temperature for 18 hours. The precipitate was collected by filtration, washed with diethyl ether and acetone, and then vacuum-dried to perform anion doping treatment to obtain 100 mg of a dark brown powder. FIG. 3 is an IR spectrum of polyaniline after heat treatment before and after anion doping treatment. From the IR spectrum shown in FIG. 3, the stretching vibration considered to correspond to the BF bond derived from the doped BF ₄ anion was observed in the vicinity of 500 cm ⁻¹ while maintaining the partial structure. Moreover, the EDX composition analysis by electron microscope observation (SEM) was performed. FIG. 4 is an EDX measurement result of the nitrogen-containing organic poorly soluble product after anion doping. In this EDX composition analysis result, since a fluorine peak was observed after anion doping, it is complementarily supported that the peak observed at 500 cm ⁻¹ in FIG. 3 is derived from the BF ₄ anion.

70% by mass of this hardly soluble HBF ₄ doped polyaniline (anion doped nitrogen-containing organic slightly soluble material), 25% by mass of ECP as a conductive material, and 5% by mass of PTEF as a binder for electrode formation are mixed. And it was set as the negative electrode compound material. By forming 10 mg of this negative electrode mixture against the mesh, a forming step was performed to produce a negative electrode. A battery cell of Example 1 was obtained by using this negative electrode, artificial graphite (12.1 mg) as a positive electrode, and LiBF ₄ propylene carbonate solution (1M) as an electrolytic solution. The battery value was evaluated by carrying out a 3-cycle charge / discharge measurement with a current value of 0.7 mA and an upper limit voltage of 3.5 V, 3.75 V, 4.0 V, and 4.2 V. 5 is a charge / discharge curve of the electricity storage device of Example 1. FIG. The measurement results are summarized in Table 1. As shown in FIG. 5 and Table 1, in the storage performance (3.5 V, 3.75 V, 4.0 V, 4.2 V) of the nitrogen-containing organic poorly soluble product after 300 ° C. insolubilization treatment and HBF ₄ doping, anions As a carrier, it was found that the capacity increased as the potential increased. The charge / discharge efficiency was 0.80 at 3.5V, 0.68 at 3.75V, 0.63 at 4.0V, and 0.66 at 4.2V.

[Example 2]
100 mg of polyaniline (average molecular weight 20000) was dispersed in acetone, 0.6 ml of tetrafluoroboric acid diethyl ether complex was added, and the mixture was stirred at room temperature for 18 hours. By removing the solvent, anion doping treatment was performed to obtain 211.3 mg of dark green powder. The anion-doped polyaniline was heated at 180 ° C. for 1.5 hours (solubilization treatment) to obtain 169.9 mg of a black powder hardly soluble in most solvents. FIG. 6 is an IR spectrum of polyaniline before and after heat treatment after anion doping. From the IR spectrum shown in FIG. 6, it was suggested that complete carbonization did not occur and the partial structure of the original polyaniline was retained. In particular, since a characteristic peak of BF ₄ salt was observed in the vicinity of 500 cm ^−1, it was considered that complete desorption of anions due to heating did not occur. This sample was difficult to disperse in most organic solvents.

70% by mass of this HBF ₄ -doped nitrogen-containing organic poorly soluble product as an active material, 25% by mass of ECP as a conductive material, and 5% by mass of PTEF as a binder for electrode formation were mixed to form a negative electrode mixture, A forming process was performed by pressing 10 mg against the mesh to obtain a negative electrode. The negative electrode and artificial graphite (12.1 mg) were used as the positive electrode, and a LiBF ₄ propylene carbonate solution (1M) was used as the electrolytic solution to obtain a battery cell of Example 2. The battery was evaluated under the same conditions as in Example 1. FIG. 7 is a charge / discharge curve of the electricity storage device of Example 2. The measurement results are summarized in Table 2. As a result, the charge / discharge curve shown in FIG. 7 was obtained, and it was found that charge / discharge was performed using anions as carriers, and the capacity increased as the potential increased. The charge / discharge efficiency was 0.78 at 3.5V, 0.85 at 3.75V, 0.83 at 4.0V, and 0.68 at 4.2V. FIG. 8 shows changes over time in battery capacity and charge / discharge efficiency in 30 cycles at the upper limit potential of 4.2V. As shown in FIG. 8, the charge amount gradually decreased by repeating 30 cycles of charge / discharge, but the decrease rate of the discharge amount was moderate compared to the charge amount. It was confirmed that the charge / discharge efficiency was slightly changed, but the efficiency of discharge / charge = about 0.7 could be maintained.

[Example 3]
210 mg of polyaniline (average molecular weight 20000) was dispersed in acetone, tetrafluoroboric acid diethyl ether complex was added, and the mixture was stirred at room temperature for 18 hours. Anion doping treatment was performed by removing the solvent to obtain 365 mg of dark green powder. A negative electrode mixture was prepared by mixing 70% by mass of this HBF ₄ -doped polyaniline, 25% by mass of ECP as a conductive material, and 5% of PTEF as a binder for electrode formation. This negative electrode mixture was made insoluble by heat treatment at 150 ° C. for 1.5 hours to obtain an electrode material. FIG. 9 is an IR spectrum before and after the heat treatment of the negative electrode mixture. From the IR spectrum shown in FIG. 9, it was suggested that complete carbonization did not occur and the partial structure of the original polyaniline was retained. In particular, since a characteristic peak of BF ₄ salt was observed in the vicinity of 500 cm ^−1, it was considered that complete desorption of anions due to heating did not occur. This negative electrode composite was difficult to disperse in most organic solvents.

The heat-treated negative electrode mixture was used as the negative electrode, artificial graphite (12.1 mg) was used as the positive electrode, and a LiBF ₄ propylene carbonate solution (1M) was used as the electrolytic solution to form a battery cell of Example 3. The battery was evaluated under the same conditions as in Example 1. FIG. 10 is a charge / discharge curve of the electricity storage device of Example 3. The measurement results are summarized in Table 3. As a result, the charge / discharge curve shown in FIG. 10 was obtained, and it was found that charge / discharge was performed using anions as carriers, and the capacity increased as the potential increased. The charge / discharge efficiency was 0.73 at 3.5V, 0.80 at 3.75V, 0.76 at 4.0V, and 0.73 at 4.2V.

[Example 4]
The composition ratio and the electronic state of the element were evaluated by XPS (PHI500 manufactured by ULVAC-PHI Co., Ltd.) according to the hardly soluble method. FIG. 11 is a production scheme of each sample of Examples 1 to 3. FIG. 12 shows XPS measurement results for B, N, and F of the samples of Examples 1 to 3. The measurement results are summarized in Table 4. As shown in FIG. 11, polyaniline, which is a raw material, is sample 1, sample 2 is heat-treated at 300 ° C., sample 2 is sample 2 is anion-doped, and sample 3 is (Example 1 so far), and the raw material is anion-doped. Sample 4 obtained by heat-treating Sample 4 at 180 ° C. (Example 2 so far), Sample 6 obtained by mixing a conductive material and a binder with Sample 4 and Sample 6 and Sample Sample 6 was heat-treated at 150 ° C. as Sample 7 (Example 3 so far). The XPS measurement results showed that there was almost no change in the binding energy in each sample, and there was no significant change in the structural bond. When the composition of the surface was confirmed, the composition ratio of B and F was high immediately after the doping, but settled to about 10 at% after the heat treatment. Although it became difficult to dissolve in an organic solvent after the poorly soluble treatment (heat treatment), it was suggested that the basic structure was not changed.

Claims (7)

A positive electrode;
A negative electrode containing a nitrogen-containing organic poorly soluble product doped with an anion and made the nitrogen-containing organic polymer poorly soluble;
An ion conductive medium that is interposed between the positive electrode and the negative electrode and conducts the anion,
An electricity storage device that is charged and discharged by movement of the anion.   The electricity storage device according to claim 1, wherein the negative electrode is heat-treated in a temperature range of 100 ° C. or higher and 500 ° C. or lower as a hardly soluble treatment.   3. The electricity storage device according to claim 1, wherein the negative electrode includes a nitrogen-containing organic poorly soluble product obtained by making polyaniline difficult to use as the nitrogen-containing organic polymer.   Using a nitrogen-containing organic polymer as a raw material, a heat treatment as a poorly soluble treatment for heating the substance containing the nitrogen-containing organic polymer, a doping treatment for doping the nitrogen-containing organic polymer or the substance derived from the nitrogen-containing organic polymer with an anion, A process for forming a negative electrode by performing a predetermined process in which a nitrogen-containing organic polymer or a material derived from the nitrogen-containing organic polymer and a binder are mixed and formed on a current collector to form a negative electrode. Production method.   In the step, the nitrogen-containing organic polymer is doped with anions, and after the anion-doped nitrogen-containing organic polymer and a binder are mixed and formed on the current collector, The manufacturing method of the negative electrode for electrical storage devices of Claim 4 which performs the heat processing which heat the substance containing the nitrogen-containing organic polymer formed on the said electrical power collector.   In the step, the nitrogen-containing organic polymer is doped with an anion, the nitrogen-containing organic polymer doped with the anion is heated, and then the heat-treated nitrogen-containing organic polymer-derived substance and The manufacturing method of the negative electrode for electrical storage devices of Claim 4 which performs the formation process which mixes with a binder and forms on a collector.   In the step, a heat treatment is performed by heating a substance containing the nitrogen-containing organic polymer using a nitrogen-containing organic polymer as a raw material, and after performing a dope treatment of doping the substance derived from the heated nitrogen-containing organic polymer with an anion, The manufacturing method of the negative electrode for electrical storage devices of Claim 4 which performs the formation process which mixes the substance derived from the nitrogen-containing organic polymer doped with an anion, and a binder, and forms on a collector.