WO2013172221A1 - Method for manufacturing electricity storage device and electricity storage device obtained using said method - Google Patents

Abstract

In order to obtain a novel electricity storage device with sufficient battery performance without the need for cumbersome work of predoping an electrode with lithium ions, provided is a method for manufacturing an electricity storage device having an electrolyte layer (3) and a positive electrode (2) and a negative electrode (4) facing each other and sandwiching the electrolyte layer (3). The method is provided with a step in which the positive electrode (2) is formed by steps a through c described hereinafter and a step in which the negative electrode (4) is formed by step d described hereinafter. a. A step in which (X), described hereinafter, is put in a reduced dedoped state. b. A step in which the anions in (Y), described hereinafter, are compensated by counterions. c. A step in which the positive electrode (2) is formed using at least the (X) in a reduced dedoped state, obtained through the above-described step a, and the (Y) in a compensated state, obtained through the above-described step b. d. A step in which the negative electrode (4) is formed using (Z), described hereinafter, in an undoped state. (X) A positive electrode active material in a doped state, the conductivity of which changes according to the insertion and desorption of ions. (Y) An anionic material. (Z) A negative electrode active material capable of ion insertion and desorption.

Description

Electric storage device manufacturing method and electric storage device obtained thereby

The present invention relates to a method for producing an electricity storage device and an electricity storage device obtained by the method, and more particularly, to produce a novel electricity storage device having sufficient battery performance without the complicated work of pre-doping electrodes with lithium ions. The present invention relates to a method and an electricity storage device obtained thereby.

In recent years, with the advancement and development of electronic technology in portable PCs, mobile phones, personal digital assistants (PDAs), secondary batteries that can be repeatedly charged and discharged are widely used as power storage devices for these electronic devices. Yes. In such an electrochemical storage device such as a secondary battery, it is desired to increase the capacity of a material used as an electrode.

The electrode of the electricity storage device contains an active material having a function capable of inserting and removing ions. The insertion / desorption of ions of the active material is also referred to as so-called doping / dedoping (or sometimes referred to as “doping / dedoping”), and the doping / dedoping amount per certain molecular structure is called a doping rate. The higher the doping rate, the higher the capacity of the battery.

Electrochemically, it is possible to increase the capacity of a battery by using a material having a large amount of ion insertion / desorption as an electrode. More specifically, lithium secondary batteries, which are attracting attention as power storage devices, use a graphite-based negative electrode that can insert and desorb lithium ions, and about one lithium ion is inserted per six carbon atoms. -Desorption and high capacity have been achieved.

Among such lithium secondary batteries, a lithium-containing transition metal oxide such as lithium manganate or lithium cobaltate is used for the positive electrode, and a carbon material capable of inserting and removing lithium ions is used for the negative electrode. Lithium secondary batteries that face each other in an electrolytic solution have a high energy density, and thus are widely used as power storage devices for the electronic devices described above.

However, the lithium secondary battery is a secondary battery that obtains electric energy by an electrochemical reaction, and has a drawback that the output density is low because the speed of the electrochemical reaction is low. Furthermore, since the internal resistance of the secondary battery is high, rapid discharge is difficult and rapid charge is also difficult. Moreover, since an electrode and electrolyte solution deteriorate by the electrochemical reaction accompanying charging / discharging, generally a lifetime, ie, a cycling characteristic, is not good.

Therefore, in order to improve the above problem, a lithium secondary battery using a conductive polymer such as polyaniline having a dopant as a positive electrode active material is also known (see Patent Document 1).

However, in general, a secondary battery having a conductive polymer as a positive electrode active material is an anion transfer type in which an anion is doped into the conductive polymer during charging and the anion is dedoped from the polymer during discharging. Therefore, when a carbon material that can insert and desorb lithium ions is used as the negative electrode active material, a cation-moving rocking chair type secondary battery in which cations move between both electrodes during charge and discharge cannot be configured. . The rocking chair type secondary battery has the advantage that the amount of the electrolyte is small, but the secondary battery having the conductive polymer as the positive electrode active material cannot do so, and contributes to the miniaturization of the electricity storage device. Can not.

In order to solve such problems, a large amount of electrolytic solution is not required, and the ion concentration in the electrolytic solution is not substantially changed, thereby improving the capacity density per volume, weight, and energy density. A cation migration type secondary battery has also been proposed. In this method, a positive electrode is formed using a conductive polymer having a polymer anion such as polyvinyl sulfonic acid as a dopant, and lithium metal is used for the negative electrode (see Patent Document 2).

JP-A-3-129679 Japanese Patent Laid-Open No. 1-132052

However, the secondary battery is still not sufficient in performance. That is, the capacity density and energy density are lower than those of a lithium secondary battery using a lithium-containing transition metal oxide such as lithium manganate or lithium cobaltate for the positive electrode.

On the other hand, an electric double layer capacitor called a lithium ion capacitor using activated carbon as a positive electrode and carbon pre-doped (pre-doped) with a lithium ion as a negative electrode can charge and discharge with a large current because ionic molecules store electric charge. Has become.

However, in the lithium ion capacitor, it is necessary to pre-dope lithium ions into the carbon of the negative electrode, and this work is complicated and time consuming.

The present invention has been made in order to solve the above-described problems in power storage devices such as conventional lithium secondary batteries and electric double layer capacitors, and requires a complicated operation of pre-doping electrodes with lithium ions. There are provided a method for producing a novel electricity storage device having sufficient battery performance and an electricity storage device obtained thereby.

The present invention relates to a method of manufacturing an electricity storage device having an electrolyte layer and a positive electrode and a negative electrode provided to face each other with the electrolyte layer interposed therebetween, the step of forming a positive electrode by the following a to c, and the formation of a negative electrode by the following d Let the manufacturing method of an electrical storage device provided with a process be a 1st summary.
a. The process of making following (X) into a reduction | restoration dedope state.
b. The process of compensating the anion of the following (Y) with a counter ion.
c. A step of forming a positive electrode using at least the reduced and doped (X) obtained from a and the compensated (Y) obtained from b.
d. A step of forming a negative electrode using the following (Z) in an undoped state.
(X) A positive electrode active material in a doped state whose conductivity is changed by insertion / extraction of ions (hereinafter also referred to as “positive electrode active material”).
(Y) Anionic material.
(Z) A negative electrode active material capable of inserting / extracting ions (hereinafter also referred to as “negative electrode active material”).

The second gist of the present invention is an electricity storage device obtained by the method for producing an electricity storage device.

That is, the present inventors have made extensive studies in order to obtain a novel power storage device that can be manufactured without complicated operations and has a high capacity density and a high energy density. In the process, we focused on the rocking chair type energy storage device mechanism, which is a cation transfer type that requires less electrolyte, and the reserve type energy storage device mechanism, which is an anion transfer type that has excellent output characteristics. Further research centered on and conducted various experiments. As a result, the inventors of the present invention can manufacture a power storage device that can easily and quickly be manufactured while eliminating the complicated work of pre-doping lithium ions on a negative electrode such as carbon, and can obtain a power storage device having sufficient battery characteristics. I found a way.

The reason why the electricity storage device according to the present invention has a high capacity is presumed to have both the above-mentioned rocking chair type and reserve type characteristics.

Thus, the present invention is a method for producing an electricity storage device having an electrolyte layer and a positive electrode and a negative electrode provided to face each other with the electrolyte layer interposed therebetween, and a method for producing an electricity storage device having the above steps a to d. . According to this production method, an electricity storage device having sufficient battery performance can be obtained, and a complicated operation of pre-doping lithium ions into a negative electrode such as carbon can be omitted, so that an electricity storage device can be produced easily and quickly. become.

Moreover, if the reduced and dedoped state of a is obtained through the steps of dedoping and reducing (X), a high-performance power storage device with excellent capacity density can be obtained. become.

Furthermore, when the reduced and dedope state a is obtained through the step of directly reducing and dedoping the above (X), a high-performance power storage device having excellent capacity density can be obtained.

As described above, a high-performance power storage device having a higher capacity density can be obtained when the power storage device is obtained by the method for manufacturing the power storage device.

The positive electrode is an electricity storage device including at least the above (X) and (Y), the negative electrode includes the above (Z), and the positive electrode (X) is in a reduction-dedoped state and is fixed in the positive electrode In the case of an electricity storage device in which the anion of (Y) is compensated by a counter ion and (Z) of the negative electrode is undoped, the capacity density is further improved.

It is sectional drawing which shows the structure of the electrical storage device obtained by manufacture of an electrical storage device, and shows the state of an assembly initial stage especially.

Hereinafter, embodiments of the present invention will be described in detail. However, the description described below is an example of embodiments of the present invention, and the present invention is not limited to the following contents.

The method for producing an electricity storage device of the present invention is, as described above, a method for producing an electricity storage device having an electrolyte layer and a positive electrode and a negative electrode provided facing each other with the electrolyte layer interposed therebetween. And a step of forming a negative electrode by the following d.
a. The process of making following (X) into a reduction | restoration dedope state.
b. The process of compensating the anion of the following (Y) with a counter ion.
c. A step of forming a positive electrode using at least the reduced and doped (X) obtained from a and the compensated (Y) obtained from b.
d. A step of forming a negative electrode using the following (Z) in an undoped state.
(X) A positive electrode active material in a doped state in which conductivity is changed by insertion / extraction of ions.
(Y) Anionic material.
(Z) A negative electrode active material capable of inserting / extracting ions.

And the electrical storage device obtained by the said manufacturing method is an electrical storage device which has the electrolyte layer 3, and the positive electrode 2 and the negative electrode 4 which were provided facing on both sides of this, as shown in FIG. (X) and (Y), the negative electrode 4 is an electricity storage device including the above (Z), and (X) of the positive electrode 2 is in a reduction-dedoped state, and is fixed in the positive electrode 2 The anion of (Y) is compensated by a counter ion, and (Z) of the negative electrode 4 is undoped.
(X) to (Z) will be described in the following order.
In addition, in FIG. 1, it shows that the positive electrode 2 and the electrolyte layer 3 contain ion (gray color part).

<About positive electrode active material (X)>
(X) is a positive electrode active material in a doped state in which the conductivity is changed by ion insertion / extraction, for example, polyacetylene, polypyrrole, polyaniline, polythiophene, polyfuran, polyselenophene, polyisothianaphthene, polyphenylene sulfide Conductive polymer materials such as polyphenylene oxide, polyazulene and poly (3,4-ethylenedioxythiophene), and carbon materials such as polyacene, graphite, carbon nanotubes, carbon nanofibers and graphene. In particular, polyaniline or polyaniline derivatives having a large electrochemical capacity are preferably used. Usually, the conductive polymer-based material is in a doped state.

Examples of the polyaniline derivative include at least a substituent such as an alkyl group, an alkenyl group, an alkoxy group, an aryl group, an aryloxy group, an alkylaryl group, an arylalkyl group, and an alkoxyalkyl group at positions other than the 4-position of the aniline. One that has one. Among them, o-substituted anilines such as o-methylaniline, o-ethylaniline, o-phenylaniline, o-methoxyaniline, o-ethoxyaniline, m-methylaniline, m-ethylaniline, m-methoxyaniline, m M-substituted anilines such as -ethoxyaniline and m-phenylaniline are preferably used. These may be used alone or in combination of two or more.

The production method of the present invention includes a step of bringing the above (X) into a reduced dedope state. In order to obtain this reductive de-doping state, (i) a method obtained by passing the above (X) into a de-doped state and a reducing step, and (ii) direct reductive desorption of (X) above. There are two methods that can be obtained through the doping step. Hereinafter, it demonstrates in order.

[About method (i)]
First, the method (i) includes a step of bringing (X) into a dedope state, and this dedope state is obtained by neutralizing a dopant contained in (X). For example, (X) in a dedope state is obtained by stirring in a solution for neutralizing the dopant (X) and then washing and filtering. Specifically, in order to dedope polyaniline having tetrafluoroboric acid as a dopant, a method of neutralizing by stirring in an aqueous sodium hydroxide solution can be mentioned.

Next, in the method (i), there is a step of changing the undoped (X) to a reduced dedope state. The reductive dedope state is obtained by reducing (X) in the dedope state. For example, stirring in a solution for reducing (X) in the dedope state, followed by washing and filtering yields (X) in the reduced dedope state. Specifically, a method of reducing polyaniline in a dedoped state by stirring in an aqueous methanol solution of phenylhydrazine can be mentioned.

[About method (ii)]
The method (ii) is a method in which reductive dedope is obtained by passing the step (X) directly into a reductive dedope state. For example, by stirring in a reducing agent solution for reducing polypyrrole and then washing and filtering, polypyrrole in a reduced and dedoped state can be obtained.

As described above, (X) in the reduced and dedoped state is obtained. And the positive electrode is comprised from the material containing (X) of this reduction | restoration dedope state, and the anionic material (Y) by which the anion was compensated with the counter ion.

<About anionic material (Y)>
Here, examples of the anionic material (Y) include a polymer anion, an anion compound having a relatively large molecular weight, and an anion compound having a low solubility in an electrolytic solution. More specifically, a compound having a carboxyl group in the molecule is preferably used, and in particular, a polycarboxylic acid that is a polymer is more preferably used because it can also serve as a binder.

Examples of the polycarboxylic acid include polyacrylic acid, polymethacrylic acid, polyvinylbenzoic acid, polyallylbenzoic acid, polymethallylbenzoic acid, polymaleic acid, polyfumaric acid, polyglutamic acid, and polyaspartic acid. Methacrylic acid is particularly preferably used. These may be used alone or in combination of two or more.

In the electricity storage device according to the present invention, when a polymer such as the above polycarboxylic acid is used, the polymer has a function as a binder and also functions as a dopant. It seems that it is also related to the improvement of the characteristics of the electricity storage device according to the invention.

The production method of the present invention includes a step of compensating the anion of the anionic material (Y) with a counter ion (becomes electrically neutral). Examples thereof include those in which the carboxylic acid of a compound having a carboxyl group in the molecule is made into a lithium type. The exchange rate for the lithium type is preferably 100%, but the exchange rate may be low depending on the situation, and is preferably 40% to 100%.

The anionic material (Y) is usually in the range of 1 to 100 parts by weight, preferably 2 to 70 parts by weight, and most preferably 5 to 40 parts by weight with respect to 100 parts by weight of the positive electrode active material (X). Used in If the amount of the anionic material (Y) relative to (X) is too small, it tends to be impossible to obtain an electricity storage device having excellent energy density, while the amount of the anionic material (Y) relative to (X) is large. Even if it is too much, there is a tendency that an energy storage device having a high energy density cannot be obtained.

<About positive electrode>
The positive electrode according to the production method of the present invention is formed as follows. For example, the anionic material (Y) is dissolved in water to form an aqueous solution, and the positive electrode active material (X) and, if necessary, a conductive assistant such as conductive carbon black or vinylidene fluoride. Add a binder and disperse well to prepare a paste. After applying this onto the current collector, the water is evaporated to form a composite having a layer of a mixture of the X component and the Y component (conducting aid and binder as required) on the current collector. A sheet electrode can be obtained.

In the positive electrode formed as described above, the anionic material (Y) is fixed in the positive electrode because it is arranged as a layer of a mixture with the X component.

The positive electrode is made of a composite composed of at least (X) and (Y), and is preferably formed into a porous sheet. Usually, the thickness of the positive electrode is preferably 1 to 500 μm, more preferably 10 to 300 μm.

The thickness of the positive electrode is obtained by measuring the positive electrode using a dial gauge (manufactured by Ozaki Mfg. Co., Ltd.), which is a flat plate with a tip shape of 5 mm in diameter, and obtaining the average of 10 measurement values with respect to the electrode surface. When a positive electrode (porous layer) is provided on the current collector and is composited, the thickness of the composite is measured in the same manner as described above, the average of the measured values is obtained, and the thickness of the current collector is subtracted. Thus, the thickness of the positive electrode can be obtained.

<About the electrolyte layer>
The electrolyte layer according to the production method of the present invention is composed of an electrolyte. For example, a sheet formed by impregnating a separator with an electrolytic solution or a sheet formed of a solid electrolyte is preferably used. The sheet made of the solid electrolyte itself also serves as a separator.

The electrolyte is composed of a solute and, if necessary, a solvent and various additives. Examples of such solutes include metal ions such as lithium ions and appropriate counter ions, sulfonate ions, perchlorate ions, tetrafluoroborate ions, hexafluorophosphate ions, hexafluoroarsenic ions, bis ions. A combination of (trifluoromethanesulfonyl) imide ion, bis (pentafluoroethanesulfonyl) imide ion, halogen ion and the like is preferably used. Therefore, specific examples of such an electrolyte include LiCF ₃ SO ₃ , LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCl. Etc.

As the solvent used as necessary, for example, at least one non-aqueous solvent such as carbonates, nitriles, amides, ethers, that is, an organic solvent is used. Specific examples of such an organic solvent include ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, acetonitrile, propionitrile, N, N′-dimethylacetamide, N-methyl-2- Examples include pyrrolidone, dimethoxyethane, diethoxyethane, and γ-butyrolactone. These may be used alone or in combination of two or more. In addition, what melt | dissolved the solute in the solvent may be called "electrolyte solution."

In the present invention, as described above, the separator can be used in various modes. As the separator, it is possible to prevent an electrical short circuit between the positive electrode and the negative electrode that are arranged to face each other across the separator. Furthermore, the separator is electrochemically stable, has a large ion permeability, and has a certain level. Any insulating porous sheet having mechanical strength may be used. Therefore, as the material of the separator, for example, a porous film made of a resin such as paper, nonwoven fabric, polypropylene, polyethylene, or polyimide is preferably used. These may be used alone or in combination of two or more.

<About negative electrode>
The negative electrode in the electricity storage device according to the present invention is formed using a negative electrode active material (Z) that can insert and desorb ions. As the negative electrode active material (Z), a carbon material, a transition metal oxide, silicon, tin or the like from which lithium ions can be inserted / extracted during oxidation / reduction is preferably used. In addition, in the present invention, “use” means not only the case where only the forming material is used, but also the case where the forming material is used in combination with another forming material. Is used at less than 50% by weight of the forming material.

Also, the thickness of the negative electrode preferably conforms to the thickness of the positive electrode.

<Production of power storage device>
The production of an electricity storage device using the above materials will be described with reference to FIG. The battery is preferably assembled in a glove box under an inert gas atmosphere such as ultra-high purity argon gas.

In FIG. 1, metal foils and meshes such as nickel, aluminum, stainless steel, and copper are appropriately used as current collectors of positive electrode 2 and negative electrode 4 (1, 5 in FIG. 1). The current collectors 1 and 5 are connected to positive and negative current extraction connection terminals (tab electrodes, not shown) using a spot welder.

Next, the positive electrode 2 and the current collector 1 are vacuum-dried. Thereafter, an undoped hard carbon electrode is pressed against the stainless steel mesh in a −100 ° C. glove box to produce a composite of the negative electrode 4 and the current collector 5.

In the glove box, a separator (not shown) is sandwiched between the positive electrode 2 and the negative electrode 4, and the positive electrode 2 and the negative electrode 4 are correctly opposed to each other in a heat-sealed laminate cell. Also, adjust the position of the separator to avoid short circuit.

シ ー ル After setting the sealant on the positive electrode and negative electrode tab parts, heat seal the tab electrode part leaving a little electrolyte inlet. Thereafter, a predetermined amount of the battery electrolyte is sucked with a micropipette, and a predetermined amount is injected from the electrolyte solution inlet of the laminate cell. Finally, the electrolyte solution inlet at the top of the laminate cell is sealed by heat sealing to complete the electricity storage device (laminate cell) of the present invention.

The power storage device of the present invention is formed into various shapes such as a film type, a sheet type, a square type, a cylindrical type, and a button type in addition to the laminate cell. In addition, the positive electrode size of the electricity storage device is preferably 1 to 300 mm on one side in the case of a laminate cell, particularly preferably 10 to 50 mm, and the electrode size of the negative electrode is 1 to 400 mm. It is preferably 10 to 60 mm. The electrode size of the negative electrode is preferably slightly larger than the positive electrode size.

According to the method for producing an electricity storage device of the present invention, a negative electrode that does not require lithium pre-doping treatment can be used, and a high-performance electricity storage device that is excellent in capacity density per active material weight and capacity density per cathode volume can be easily produced. .

As the charge / discharge mechanism of the electricity storage device of the present invention, the anionic material (Y) that is a polymer is used as a binder, but this binder itself functions as a dopant, and a rocking chair type mechanism exists in part. It is assumed. That is, although not yet clarified accurately, a rocking chair type mechanism in which cations such as lithium ions move from the negative electrode to the positive electrode during discharging and cations move from the positive electrode to the negative electrode during charging. Is assumed to exist.

Next, examples will be described. However, the present invention is not limited to these examples.

First, prior to the production of an electricity storage device as an example, the following components were prepared.

[Preparation of Doped Cathode Active Material (X) whose Conductivity is Changed by Ion Insertion and Desorption]
As the positive electrode active material (X), conductive polyaniline powder using tetrafluoroboric acid as a dopant was prepared as follows.

To a 300 mL glass beaker containing 138 g of ion-exchanged water, 84.0 g (0.402 mol) of a 42 wt% concentration tetrafluoroboric acid aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade) is added to a magnetic stirrer. While stirring, 10.0 g (0.107 mol) of aniline was added thereto. When aniline was added to the tetrafluoroboric acid aqueous solution, the aniline was dispersed as oily droplets in the tetrafluoroboric acid aqueous solution, but then dissolved in water within a few minutes, and the uniform and transparent aniline aqueous solution. Became. The aniline aqueous solution thus obtained was cooled to −4 ° C. or lower using a low temperature thermostat.

Next, 11.63 g (0.134 mol) of manganese dioxide powder (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1) as an oxidizing agent is added little by little to the above aniline aqueous solution, and the temperature of the mixture in the beaker is −1. The temperature was not exceeded. Thus, by adding an oxidizing agent to the aniline aqueous solution, the aniline aqueous solution immediately turned black-green. Thereafter, when stirring was continued for a while, a black-green solid started to be formed.

Thus, after adding the oxidizing agent over 80 minutes, the reaction mixture containing the produced reaction product was further stirred for 100 minutes while cooling. Then, using a Buchner funnel and a suction bottle, the obtained solid was No. No. 2 (manufactured by ADVANTEC) was suction filtered with a filter paper to obtain a powder. This powder was stirred and washed in a 2 mol / L tetrafluoroboric acid aqueous solution using a magnetic stirrer. Subsequently, it was stirred and washed several times with acetone, and this was filtered under reduced pressure. The obtained powder was vacuum-dried at room temperature (25 ° C.) for 10 hours to obtain 12.5 g of conductive polyaniline having tetrafluoroboric acid as a dopant (hereinafter simply referred to as “conductive polyaniline”). The conductive polyaniline was a bright green powder.

[Conductivity of conductive polyaniline powder]
After pulverizing 130 mg of the conductive polyaniline powder in a smoked mortar, vacuum-pressing was performed for 10 minutes under a pressure of 75 MPa using a KBr tablet molding machine for infrared spectrum measurement, and a conductive polyaniline disk having a thickness of 720 μm was formed. Obtained. The conductivity of the disk measured by the 4-terminal method conductivity measurement by the Van der Pau method was 19.5 S / cm.

[Preparation of anionic material (Y)]
Using polyacrylic acid (Wako Pure Chemical Industries, Ltd., weight average molecular weight 25,000) as an anionic material (Y) compensated for anion with counter ion, adding carboxylic acid equivalent lithium hydroxide in aqueous solution, A uniform and viscous polyacrylic acid aqueous solution having a concentration of 4.4% by weight was prepared.

[Preparation of negative electrode active material (Z) capable of inserting and removing ions]
As the negative electrode active material (Z), hard carbon (Bellfine LN-0010, manufactured by Air Water Co., Ltd.) was prepared.

[Example 1] (FIG. 1)
<Process of making conductive polyaniline powder into dedope state>
The conductive polyaniline powder in a doped state obtained as described above is placed in a 2 mol / L aqueous sodium hydroxide solution, stirred for 30 minutes in a 3 L separable flask, and the tetrafluoroboric acid as a dopant is removed by a neutralization reaction. Doped. The dedoped polyaniline was washed with water until the filtrate became neutral, then stirred and washed in acetone, and filtered under reduced pressure using a Buchner funnel and a suction bottle to obtain a dedoped polyaniline powder on No. 2 filter paper. . This was vacuum-dried at room temperature for 10 hours to obtain a brown undoped polyaniline powder.

<The process which makes polyaniline powder of a dedope state reduction | restoration dedope>
Next, this dedope polyaniline powder was put into a methanol solution of phenylhydrazine and subjected to reduction treatment for 30 minutes with stirring. The color of the polyaniline powder changed from brown to gray by reduction. After the reaction, it was washed with methanol, washed with acetone, filtered, and vacuum dried at room temperature to obtain polyaniline in a reduced and dedoped state.

[Conductivity of polyaniline powder in reduced and undoped state]
After pulverizing 130 mg of the above polyaniline powder in the reduced dedope state in a smoked mortar, vacuum reduced pressure molding was performed for 10 minutes under a pressure of 75 MPa using a KBr tablet molding machine for infrared spectrum measurement, and a reduced dedope having a thickness of 720 μm. A polyaniline disk in state was obtained. The electric conductivity of the disk measured by the 4-terminal conductivity measurement by the Van der Pau method was 5.8 × 10 ⁻³ S / cm.

<Step of Forming Positive Electrode Using (X) in Reduced Dedoped State and (Y)>
21.0 g of the lithiated polyacrylic acid aqueous solution prepared as the Y component was prepared.

After mixing 4 g of the above-prepared polyaniline powder in a reduced dedope state and 0.5 g of conductive carbon black (Denka Black, Denki Kagaku Kogyo Co., Ltd.) powder, this was mixed with the above polyacrylic acid having a concentration of 4.4 wt%. In addition to 21.0 g of aqueous solution, well kneaded with a spatula. This was subjected to ultrasonic treatment for 1 minute with an ultrasonic homogenizer to obtain a paste having fluidity. This paste was further defoamed using a vacuum suction bell and a rotary pump.

Using a tabletop automatic coating apparatus (manufactured by Tester Sangyo Co., Ltd.), using a doctor blade type applicator with a micrometer, the solution coating thickness was adjusted to 360 μm, and the defoaming paste was applied at a coating speed of 10 mm / second. It apply | coated on the etching aluminum foil (The Hosen company make, 30CB) for electric double layer capacitors. Subsequently, after leaving at room temperature for 45 minutes, it dried on the hotplate with a temperature of 100 degreeC. Then, using a vacuum press machine (KVHC, manufactured by Kitagawa Seiki Co., Ltd.), sandwiched between 15 cm square stainless steel plates and pressed at a temperature of 140 ° C. and a pressure of 1.5 MPa for 5 minutes to produce a porous polyaniline sheet electrode Thus, a composite of the positive electrode and the current collector was obtained.

<Production of materials for electricity storage devices>
First, the following materials were prepared before assembling the electricity storage device (lithium secondary battery).

As the positive electrode, the polyaniline sheet electrode obtained above is used, and as the negative electrode, a hard carbon electrode not pre-doped with lithium ions is used. As the separator, non-woven fabric TF40-50 (porosity: 55%) purchased from Hosen Co., Ltd. was used, and these electrodes and separator were placed in a vacuum dryer at 100 ° C. for 5 hours before cell assembly. Vacuum dried. As the electrolytic solution, an ethylene carbonate / dimethyl carbonate solution (manufactured by Kishida Chemical Co., Ltd.) of lithium tetrafluoroborate (LiBF ₄ ) having a concentration of 1 mol / dm ³ was used.

The assembly of a laminate cell, which is an electricity storage device (lithium secondary battery), using the prepared material is shown below. The battery was assembled in a glove box under an ultrahigh purity argon gas atmosphere (dew point in the glove box: −100 ° C.).

The electrode size of the positive electrode for the laminate cell is 27 mm × 27 mm, the negative electrode size is 29 mm × 29 mm, which is slightly larger than the positive electrode size.

As the negative electrode current extraction tab electrode, a nickel metal foil having a thickness of 50 μm was connected by a spot welder. As the positive electrode current extraction tab electrode, an aluminum metal foil having a thickness of 50 μm was connected to the aluminum foil of the positive electrode current collector with a spot welder. The positive electrode composite, the hard carbon as the negative electrode, the stainless mesh, and the separator are placed in a glove box with a dew point of −100 ° C., and the hard carbon electrode is pressed against the stainless steel mesh of the current collector in the glove box. And a current collector composite.

Also, in the glove box, put a separator between this positive electrode and negative electrode, and set them in a laminate cell that is heat-sealed on three sides, so that the positive electrode and negative electrode face each other correctly and do not short-circuit. The position of the separator was also adjusted, and a sealing agent was set on the positive electrode and negative electrode tab portions, and the tab electrode portion was heat-sealed leaving a little electrolyte solution inlet. Then, a predetermined amount of battery electrolyte is sucked with a micropipette, and a predetermined amount is injected from the electrolyte inlet of the laminate cell. Finally, the electrolyte inlet at the top of the laminate cell is sealed by heat sealing, and the laminate cell As completed.

The characteristics of the lithium secondary battery assembled in this way were performed in a constant current / constant voltage charging / constant current discharging mode using a battery charging / discharging device (Hokuto Denko, SD8). The end-of-charge voltage is 3.8 V. After the voltage reaches 3.8 V by constant current charging, constant voltage charging at 3.8 V is performed for 2 minutes, and then constant current discharge is performed until the end-of-discharge voltage is 2.0 V. went. The charge / discharge current was 0.18 mA. In the 15th cycle, the weight energy density was 225 Wh / kg.

In the above embodiments, specific forms in the present invention have been described. However, the above embodiments are merely examples and are not construed as limiting. Various modifications apparent to those skilled in the art are contemplated to be within the scope of this invention.

The method for producing an electricity storage device of the present invention can be suitably used as a method for producing an electricity storage device such as a lithium secondary battery. The power storage device of the present invention can be used for the same applications as conventional secondary batteries. For example, portable electronic devices such as portable PCs, mobile phones, and personal digital assistants (PDAs), hybrid electric vehicles, Widely used in power sources for driving automobiles, fuel cell vehicles and the like.

1 Current collector (for positive electrode)
2 Positive electrode 3 Electrolyte layer 4 Negative electrode 5 Current collector (for negative electrode)

Claims (5)

1. A method of manufacturing an electricity storage device having an electrolyte layer and a positive electrode and a negative electrode provided opposite to each other, the method comprising the steps of forming a positive electrode by the following a to c and forming a negative electrode by the following d A process for producing an electricity storage device characterized by
   a. The process of making following (X) into a reduction | restoration dedope state.
   b. The process of compensating the anion of the following (Y) with a counter ion.
   c. A step of forming a positive electrode using at least the reduced and doped (X) obtained from a and the compensated (Y) obtained from b.
   d. A step of forming a negative electrode using the following (Z) in an undoped state.
   (X) A positive electrode active material in a doped state in which conductivity is changed by insertion / extraction of ions.
   (Y) Anionic material.
   (Z) A negative electrode active material capable of inserting / extracting ions.
2. The method for producing an electricity storage device according to claim 1, wherein the reduced and dedoped state of a is obtained through a step of dedoping (X) and a step of reduction.
3. The method for producing an electricity storage device according to claim 1, wherein the reductive and dedope state of a is obtained through a step of directly reducing and dedoping the (X).
4. An electricity storage device obtained by the method for producing an electricity storage device according to any one of claims 1 to 3.
5. The positive electrode is an electricity storage device including at least the above (X) and (Y), the negative electrode includes the above (Z), and the positive electrode (X) is in a reduction-dedoped state and is fixed in the positive electrode 5. The electricity storage device according to claim 4, wherein the anion of (Y) is compensated with a counter ion, and (Z) of the negative electrode is undoped.

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