JP2016167403A - Nonaqueous electrolyte power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte power storage element, high in discharge capacity and excellent in cycle characteristics and rapid charge/discharge characteristics.SOLUTION: A nonaqueous electrolyte power storage element includes: a positive electrode including a positive electrode active material capable of inserting/desorbing anions; a negative electrode including a negative electrode active material; and a nonaqueous electrolyte. In the nonaqueous electrolyte power storage element, the positive electrode contains a conductive polymer.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a non-aqueous electrolyte storage element.

  In recent years, with the miniaturization and high performance of portable devices, the characteristics of non-aqueous electrolyte storage elements having a high energy density have been improved and become widespread. In addition, the development of non-aqueous electrolyte storage elements with higher capacity and superior safety has been promoted, and installation in electric vehicles and the like has begun.

  For this reason, non-aqueous electrolysis in which a conductive polymer, a carbon material or the like is used as a positive electrode as a power storage element having high energy density and suitable for high-speed charge / discharge, and a lithium salt is dissolved in a negative electrode such as carbon and a non-aqueous solvent During charging, the anion in the non-aqueous electrolyte is inserted into the positive electrode and the cation is inserted into the negative electrode, and during discharging, the anion and cation inserted into the positive electrode and the negative electrode are desorbed into the electrolytic solution to charge and discharge. The so-called dual intercalation type non-aqueous electrolyte storage element is expected to be put to practical use.

The dual intercalation type power storage element has an operating voltage range of about 2.5 V to 5.4 V, and the maximum voltage is about 1 V higher than 4.2 V of the lithium ion secondary battery. Even in such a high operating voltage range, the electrode member is required to exist stably. In particular, the binder plays an important role in connecting the active materials to make the electrode exist stably. Furthermore, the presence of a binder is essential in order to follow the swelling and shrinkage of the active material accompanying charging and discharging.
On the other hand, the electrode is required to have low electrical resistance in order to move the stored electricity quickly without loss, but the binder added to a general secondary battery has low electrical conductivity and high electrical conductivity. There are many resistances. If a binder with low electrical conductivity is added, the electrical resistance of the electrode is increased, which hinders (impedes) the movement of electrons or ions, and when rapid charging / discharging is performed, the performance cannot be sufficiently exhibited. Therefore, it is necessary to reduce the amount of the binder as much as possible and improve the conductivity of the binder itself.

  Therefore, if a conductive polymer having electrical conductivity and resistance even in a high voltage range can be incorporated into the binder, battery characteristics that cannot be obtained with a conventional binder may be obtained. For example, a technique using polyaniline sulfonic acid, which is a conductive polymer, as a binder for a negative electrode film for a lithium ion secondary battery has been proposed (see Patent Document 1).

However, the conventional lithium ion secondary battery is an intercalation to the positive electrode and the negative electrode of only Li ions having a small ion radius compared to the anion, and the swelling shrinkage is small compared to the electrode accompanied with the anion intercalation. The range is also low. Therefore, as an effect of improving the storage element characteristics, although an increase in the capacity retention rate at the 54th cycle can be confirmed, there is a problem that an effect of suppressing deterioration of the storage element itself is not sufficiently obtained.
Therefore, an object of the present invention is to provide a nonaqueous electrolyte storage element having a high discharge capacity and excellent cycle characteristics and rapid charge / discharge characteristics.

The nonaqueous electrolyte storage element of the present invention as a means for solving the above problems includes a positive electrode including a positive electrode active material capable of inserting or removing anions, a negative electrode including a negative electrode active material, a nonaqueous electrolyte, A non-aqueous electrolyte storage element comprising:
The positive electrode contains a conductive polymer.

  ADVANTAGE OF THE INVENTION According to this invention, the said various problems in the past can be solved, and the non-aqueous-electrolyte electrical storage element which is high discharge capacity and excellent in cycling characteristics and rapid charge / discharge characteristics can be provided.

FIG. 1 shows (II), (IV), (VI) when the discharge capacity, discharge current value, and charge current value at the reference current value (I) in Examples 11 and 12 and Comparative Example 2 were increased. , (VIII) discharge capacity values are plotted. FIG. 2 is a schematic view showing an example of the nonaqueous electrolyte storage element of the present invention.

(Non-aqueous electrolyte storage element)
The nonaqueous electrolyte storage element of the present invention includes a positive electrode, a negative electrode, and a nonaqueous electrolyte, and further includes other members as necessary.

<Positive electrode>
The positive electrode is not particularly limited as long as it contains a positive electrode storage material (positive electrode active material or the like) and a conductive polymer, and can be appropriately selected according to the purpose. For example, a positive electrode active material and a positive electrode current collector Examples include a positive electrode provided with a positive electrode material containing a conductive polymer.
There is no restriction | limiting in particular as a shape of the said positive electrode, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

-Positive electrode material-
The positive electrode material is not particularly limited and may be appropriately selected depending on the purpose.For example, the positive electrode material includes a positive electrode active material and a conductive polymer, and further includes a conductive additive, a binder, a thickener, and the like as necessary. Comprising.

--- Positive electrode active material-
The positive electrode active material is not particularly limited as long as it can insert or desorb anions, and can be appropriately selected according to the purpose. Examples thereof include carbonaceous materials.
Examples of the carbonaceous material include graphite (graphite) such as coke, artificial graphite, and natural graphite, and pyrolysis products of organic substances under various pyrolysis conditions.

--Conductive polymer--
The conductive polymer plays a role as a binder in addition to imparting electrical conductivity, and one type of conductive polymer may be used alone as the binder, or two or more types are used in combination with a binder described later. You can also
Examples of the conductive polymer include polypyrrole, polyaniline, polythiophene, and derivatives thereof. Among these, those having an electrical conductivity of 100 S / cm or more are preferable, polypyrrole, polyaniline sulfonic acid, and poly (3,4-ethylenedioxythiophene) (PEDOT) are more preferable, and PEDOT is particularly preferable. The PEDOT has high conductivity and can reduce the impedance of the electrode as compared with the case where other conductive polymers are used.
Since the PEDOT alone has very low solubility in a solvent, a mixture (PEDOT / PSS) of the PEDOT and poly (4-styrenesulfonic acid) (PSS) is preferable.
The content of the conductive polymer is preferably 0.1% by mass to 10% by mass and more preferably 0.3% by mass to 3% by mass with respect to the total amount of the positive electrode material excluding the positive electrode current collector from the positive electrode. . When the content is less than 0.1% by mass, the binding force between the positive electrode active materials and between the positive electrode active material and the positive electrode current collector may decrease, and when the content exceeds 10% by mass, the capacity decreases. In addition, the high current characteristics may be deteriorated due to an increase in impedance. Moreover, the applicability | paintability to the positive electrode electrical power collector of the coating material comprised from a binder, a positive electrode active material, and water may also fall.

--Binder and thickener--
The binder and thickener are not particularly limited as long as they are materials that are stable with respect to the solvent and electrolyte used during electrode production and the applied potential, and can be appropriately selected according to the purpose. Fluorine binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber, acrylate latex, carboxymethylcellulose (CMC) , Methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, phosphoric acid starch, casein and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), acrylate latex, and carboxymethyl cellulose (CMC) are preferable.

--Conductive aid--
Examples of the conductive aid include metal materials such as copper and aluminum, and carbonaceous materials such as carbon black, acetylene black, and carbon nanotubes. These may be used individually by 1 type and may use 2 or more types together.

-Positive electrode current collector-
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of the said positive electrode electrical power collector, According to the objective, it can select suitably.
The material of the positive electrode current collector is formed of a conductive material and is not particularly limited as long as it is stable with respect to the applied potential, and can be appropriately selected according to the purpose. Examples include steel, nickel, aluminum, titanium, and tantalum. Among these, stainless steel and aluminum are particularly preferable.
There is no restriction | limiting in particular as a shape of the said positive electrode electrical power collector, According to the objective, it can select suitably.
The size of the positive electrode current collector is not particularly limited as long as it is a size that can be used for a non-aqueous electrolyte storage element, and can be appropriately selected according to the purpose.

-Method for producing positive electrode-
The positive electrode comprises a positive electrode material formed into a slurry by adding the binder, the thickener, the conductive agent, a solvent, and the like to the positive electrode active material and the conductive polymer as necessary on the positive electrode current collector. It can manufacture by apply | coating to and drying.
There is no restriction | limiting in particular as said solvent, According to the objective, it can select suitably, For example, an aqueous solvent, an organic solvent, etc. are mentioned. Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP) and toluene.
In addition, the positive electrode active material can be roll-formed as it is to form a sheet electrode, or can be formed into a pellet electrode by compression molding.

<Negative electrode>
There is no restriction | limiting in particular in the said negative electrode, According to the objective, it can select suitably, For example, the negative electrode provided with the negative electrode material which has a negative electrode active material on a lithium metal foil and a negative electrode collector, etc. are mentioned.
There is no restriction | limiting in particular as a shape of the said negative electrode, According to the objective, it can select suitably, For example, flat form, metal foil shape, etc. are mentioned.
The negative electrode preferably contains a conductive polymer. As the conductive polymer, the same polymer as the positive electrode can be used. When the negative electrode contains a conductive polymer and the positive electrode and the negative electrode both contain a conductive polymer, the cycle life is greatly improved.

-Negative electrode material-
The negative electrode material includes at least a negative electrode storage material (negative electrode active material or the like), and further includes a conductive additive, a binder, a thickener, and the like as necessary.

--- Negative electrode active material-
The negative electrode active material is not particularly limited as long as it is a substance that can occlude or release at least one of metallic lithium and lithium ions, and specifically, a lithium such as carbonaceous material, antimony tin oxide, and silicon monoxide. Metal oxide that can occlude and release, metal such as aluminum, tin, silicon, and zinc or metal alloy that can be alloyed with lithium, metal that can be alloyed with lithium, and an alloy compound containing lithium and a composite alloy compound of lithium And lithium metal nitride such as cobalt lithium nitride and lithium titanate. These may be used individually by 1 type and may use 2 or more types together. Examples of the carbonaceous material include graphite (graphite) such as coke, artificial graphite, and natural graphite, and pyrolysis products of organic substances under various pyrolysis conditions. Among these, artificial graphite and natural graphite are particularly preferable.

--Binder and thickener--
The binder and thickener are not particularly limited as long as they are materials that are stable with respect to the solvent and electrolyte used during electrode production and the applied potential, and can be appropriately selected according to the purpose. Fluorine binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber, acrylate latex, carboxymethylcellulose (CMC) , Methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, phosphoric acid starch, casein and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) are preferable.

--Conductive aid--
Examples of the conductive aid include metal materials such as copper and aluminum, and carbonaceous materials such as carbon black, acetylene black, and carbon nanotubes. These may be used individually by 1 type and may use 2 or more types together.

-Negative electrode current collector-
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of the said negative electrode collector, According to the objective, it can select suitably.
The material of the negative electrode current collector is formed of a conductive material and is not particularly limited as long as it is stable with respect to the applied potential, and can be appropriately selected according to the purpose. Examples include steel, nickel, aluminum, and copper. Among these, stainless steel, copper, and aluminum are particularly preferable.
There is no restriction | limiting in particular as a shape of the said negative electrode electrical power collector, According to the objective, it can select suitably.
The size of the negative electrode current collector is not particularly limited as long as it is a size that can be used for a non-aqueous electrolyte storage element, and can be appropriately selected according to the purpose.

-Negative electrode manufacturing method-
The negative electrode is prepared by applying a negative electrode material in the form of a slurry by adding the binder, the thickener, the conductive agent, a solvent and the like to the negative electrode active material as necessary, and drying the negative electrode current collector. Can be manufactured. As the solvent, the same solvent as that for the positive electrode can be used.
In addition, the negative electrode active material added with the binder, the thickener, the conductive agent, and the like is roll-formed as it is to form a sheet electrode, a pellet electrode by compression molding, vapor deposition, sputtering, plating, etc. A thin film of the negative electrode active material may be formed on the negative electrode current collector.

<Non-aqueous electrolyte>
The non-aqueous electrolyte is an electrolyte obtained by dissolving an electrolyte salt in a non-aqueous solvent.
There is no restriction | limiting in particular as said non-aqueous solvent, According to the objective, it can select suitably, For example, an aprotic organic solvent etc. are mentioned.
Examples of the aprotic organic solvent include carbonate-based organic solvents such as chain carbonates and cyclic carbonates, and low viscosity solvents are preferable. Among these, a chain carbonate is preferable from the viewpoint that the electrolyte salt has a high dissolving power.
Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC). Among these, dimethyl carbonate (DMC) is preferable.

  The content of the DMC is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 70% by mass or more and more preferably 83% by mass or more with respect to the non-aqueous solvent. If the content of the DMC is less than 70% by mass, the amount of the cyclic substance having a high dielectric constant increases when the remaining solvent is a cyclic substance (cyclic carbonate, cyclic ester, etc.) having a high dielectric constant. When a non-aqueous electrolyte solution having a high concentration of 3M or more is produced, the viscosity becomes too high, which may cause problems in terms of penetration of the non-aqueous electrolyte solution into the electrode and ion diffusion.

Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), and fluoroethylene carbonate (FEC).
When a mixed solvent combining ethylene carbonate (EC) as the cyclic carbonate and dimethyl carbonate (DMC) as the chain carbonate is used, the mixing ratio of ethylene carbonate (EC) and dimethyl carbonate (DMC) is particularly There is no restriction | limiting, According to the objective, it can select suitably.

As the non-aqueous solvent, an ester organic solvent such as a cyclic ester or a chain ester, an ether organic solvent such as a cyclic ether or a chain ether, or the like can be used as necessary.
Examples of the cyclic ester include γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone.
Examples of the chain ester include propionic acid alkyl ester, malonic acid dialkyl ester, acetic acid alkyl ester (methyl acetate (MA), ethyl acetate, etc.), formic acid alkyl ester (methyl formate (MF), ethyl formate, etc.) and the like. Can be mentioned.
Examples of the cyclic ether include tetrahydrofuran, alkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane, and the like.
Examples of the chain ether include 1,2-dimethoxyethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether.

<Electrolyte salt>
The electrolyte salt is preferably a lithium salt.
The lithium salt is not particularly limited as long as it is dissolved in a non-aqueous solvent and exhibits high ionic conductivity, and can be appropriately selected according to the purpose. For example, lithium hexafluorophosphate (LiPF ₆ ) Lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), lithium borofluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium trifluorometasulfonate (LiCF ₃ SO ₃ ), lithium bistri Fluoromethylsulfonylimide (LiN (CF ₃ SO ₂ ) ₂ ), lithium bisperfluoroethylsulfonylimide (LiN (C ₂ F ₅ SO ₂ ) ₂ ), and the like can be given. These may be used individually by 1 type and may use 2 or more types together. Among these, LiPF ₆ is particularly preferable from the viewpoint of the amount of occlusion of anions in the carbon electrode.
There is no restriction | limiting in particular as a density | concentration of the said electrolyte salt, Although it can select suitably according to the objective, From the point of coexistence of a capacity | capacitance and an output, 0.5 mol / L-6 mol / L in the said non-aqueous solvent. Is preferable, and 2 mol / L to 4 mol / L is more preferable.

<Separator>
The separator is provided between the positive electrode and the negative electrode in order to prevent a short circuit between the positive electrode and the negative electrode.
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of the said separator, According to the objective, it can select suitably.
Examples of the material of the separator include paper such as kraft paper, vinylon mixed paper, synthetic pulp mixed paper, cellophane, polyethylene graft membrane, polyolefin nonwoven fabric such as polypropylene melt blown nonwoven fabric, polyamide nonwoven fabric, glass fiber nonwoven fabric, and micropore membrane. Can be mentioned. Among these, those having a porosity of 50% or more are preferable from the viewpoint of electrolyte solution retention.
As the shape of the separator, a non-woven fabric system having a higher porosity is more preferable than a thin film type having micropores.
The average thickness of the separator is preferably 20 μm or more from the viewpoint of short circuit prevention and electrolyte solution retention.
There is no restriction | limiting in particular as long as the magnitude | size of the said separator is a magnitude | size which can be used for a non-aqueous electrolyte electrical storage element, It can select suitably according to the objective.
The separator may have a single layer structure or a laminated structure.

<Method for Manufacturing Nonaqueous Electrolyte Storage Element>
The non-aqueous electrolyte storage element of the present invention is manufactured by assembling the positive electrode, the negative electrode, and the non-aqueous electrolyte and a separator used as necessary into an appropriate shape. Furthermore, it is also possible to use other components such as an outer can if necessary.
There is no restriction | limiting in particular as a method of assembling the said non-aqueous electrolyte electrical storage element, It can select suitably from the methods employ | adopted normally.

  Here, FIG. 2 is a schematic view showing an example of the nonaqueous electrolyte storage element of the present invention. The non-aqueous electrolyte storage element 10 includes a positive electrode 1 including a positive electrode active material capable of reversibly storing or releasing anions in an outer can 4, a negative electrode 2 including a negative electrode active material, and a positive electrode 1 and a negative electrode 2. The separator 3 is accommodated therebetween, and the positive electrode 1, the negative electrode 2, and the separator 3 are immersed in a non-aqueous electrolyte solution (not shown) formed by dissolving an electrolyte salt in a non-aqueous solvent. In addition, 5 is a negative electrode lead wire and 6 is a positive electrode lead wire.

  There is no restriction | limiting in particular about the shape of the nonaqueous electrolyte electrical storage element of this invention, According to the use, it can select suitably from various shapes employ | adopted generally. Examples of the shape include a cylinder type in which a sheet electrode and a separator are spiral, a cylinder type having an inside-out structure in which a pellet electrode and a separator are combined, and a coin type in which a pellet electrode and a separator are stacked.

Examples of the non-aqueous electrolyte storage element of the present invention include a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte capacitor.
The use of the non-aqueous electrolyte storage element is not particularly limited and can be used for various purposes. For example, a notebook computer, a pen input personal computer, a mobile personal computer, an electronic book player, a mobile phone, a mobile fax, a portable copy, Portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, motor, lighting equipment, toy, game machine, Clocks, strobes, cameras, etc.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Preparation of nonaqueous electrolyte storage element>
-Production of electrodes-
Carbon powder (manufactured by TIMCAL, KS-6) as a positive electrode active material, acetylene black (denka black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive additive, and carboxyl methyl cellulose (Daicel 2200, Daicel Chemical Industries, Ltd.) as a thickener Company), acrylate latex (TRD202A, manufactured by JSR Corporation) as a binder, and PEDOT / PSS (Clevios (registered trademark), PH500, manufactured by H.C. The mass ratio is 87.2% by mass: 6.6% by mass: 3.3% by mass: 2.2% by mass: 0.7% by mass, and water is added to adjust the viscosity appropriately. The resulting slurry was applied to one side of a 20 μm thick aluminum foil using a doctor blade. The average weight per unit area (mass of carbon active material powder in the coated positive electrode) after drying was 20 mg / cm ² . This was punched out to a diameter of 16 mm to obtain a positive electrode.
A lithium metal foil having a diameter of 16 mm was used for the negative electrode.

-Separator-
Two separators prepared by punching glass filter paper (GA100, manufactured by ADVANTEC) to a diameter of 16 mm were prepared.

-Non-aqueous electrolyte-
As the non-aqueous electrolyte, a 2 mol / L LiPF ₆ dimethyl carbonate (DMC) solution (manufactured by Kishida Chemical Co., Ltd.) was used.

-Production of electricity storage elements-
The positive electrode and the separator were vacuum-dried at 150 ° C. for 4 hours, and then a 2032 type coin power storage device was assembled in a dry argon glove box.
The coin cell was filled with the non-aqueous electrolyte to produce a power storage device.
About the obtained electrical storage element, the charging / discharging test was done as follows.

<Charge / discharge test>
The produced electrical storage element was hold | maintained in the 25 degreeC thermostat, and the charging / discharging test was implemented on the following conditions.
For the charge / discharge test, an automatic battery evaluation device of 1024B-7V0.1A-4 (manufactured by Electrofield) was used. The reference current value was set to 2.0 mA, and the battery was charged to a charge end voltage of 5.2V. After the first charge, the battery was discharged to 3.0V. Between charging and discharging, and between discharging and charging, a pause of 5 minutes was put, and this charging and discharging was repeated. In addition, all the charging was performed at a constant current with a cutoff voltage of 5.2 V, the discharging was performed at a cutoff voltage of 3.0 V, and a pause of 5 minutes was inserted between the discharging and charging. This charging was repeated until the capacity decreased by 20% or more from the first discharge capacity.
When the discharge capacity at the 10th cycle and the discharge capacity at the 1st cycle were taken as 100%, the number of cycles when the discharge capacity retention rate became 80% or less was determined. The results are shown in Table 1.

(Example 2)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, the binder, and the conductive polymer are each in a mass ratio of solid content of 87.2% by mass: 6.6% by mass: 3.3% by mass: 2.6% by mass: 0.3% by mass The electrodes and the electricity storage device were prepared in the same manner as in Example 1 except that water was added to prepare a slurry. The charge / discharge test was conducted in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, the binder, and the conductive polymer are each in a mass ratio of solid content of 87.2% by mass: 6.6% by mass: 3.3% by mass: 1.8% by mass: 1.1% by mass The electrode and the electricity storage device were prepared in the same manner as in Example 1 except that the slurry was prepared by adding water. The charge / discharge test was conducted in the same manner as in Example 1. The results are shown in Table 1.

Example 4
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, and the conductive polymer were each 87.2 mass%: 6.6 mass%: 3.3 in terms of the solid mass ratio. % By mass: mixed to 2.9% by mass, except that water was added to prepare a slurry in the same manner as in Example 1 to produce an electrode and a power storage device. A charge / discharge test was conducted. The results are shown in Table 1.

(Example 5)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, and the conductive polymer were each in a solid mass ratio of 87.1% by mass: 6.4% by mass: 3.0. % By mass: mixed to be 3.5% by mass, except that water was added to prepare a slurry, and in the same manner as in Example 1, an electrode and an electricity storage device were produced. A charge / discharge test was conducted. The results are shown in Table 1.

(Example 6)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, and the conductive polymer were each 83.8% by mass: 6.3% by mass: 3.2 in terms of solid mass ratio. % By mass: mixed to be 6.7% by mass, except that water was added to prepare a slurry, and in the same manner as in Example 1, an electrode and a storage element were produced. A charge / discharge test was conducted. The results are shown in Table 1.

(Example 7)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, and the conductive polymer were each 80.8% by mass: 6.1% by mass: 3.1 in terms of solid mass ratio. Mass%: mixed to be 10.0% by mass, except that water was added to prepare a slurry, and in the same manner as in Example 1, an electrode and a power storage device were produced. A charge / discharge test was conducted. The results are shown in Table 1.

(Example 8)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, and the conductive polymer were each in a solid mass ratio of 80.6% by mass: 6.1% by mass: 3.1. Mass%: 10.2% by mass was mixed, and except that water was added to prepare a slurry, an electrode and a storage element were produced in the same manner as in Example 1, and as in Example 1, A charge / discharge test was conducted. The results are shown in Table 1.

Example 9
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, the binder, and the conductive polymer are each in a mass ratio of solid content of 87.2% by mass: 6.6% by mass: 3.3% by mass: 2.8% by mass: 0.1% by mass The electrode and the electricity storage device were prepared in the same manner as in Example 1 except that water was added to prepare a slurry. The charge / discharge test was conducted in the same manner as in Example 1. The results are shown in Table 1.

(Example 10)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, the binder, and the conductive polymer are each in a mass ratio of solid content of 87.3 mass%: 6.5 mass%: 3.32% by mass: 2.8% by mass: 0.08% by mass The electrodes and the electricity storage device were produced in the same manner as in Example 1 except that water was added to prepare a slurry. The charge / discharge test was conducted in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, and the binder are each in a solid mass ratio of 87.2% by mass: 6.6% by mass: 3.3% by mass. : 2.9% by mass was mixed, and except that water was added to prepare a slurry, an electrode and an electricity storage device were prepared in the same manner as in Example 1, and charge / discharge was performed in the same manner as in Example 1. A test was conducted. The results are shown in Table 1.

表１の結果から、導電性ポリマーの含有量に対するサイクル寿命を比較すると、サイクル寿命は導電性ポリマーを０．７質量％含有した実施例１が最も高く、導電性ポリマーの含有量が最も少ない実施例１０及び最も多い実施例８においては、比較例１と比べて、サイクル寿命の向上は見られなかった。これは、導電性ポリマーの含有量が０．１質量％未満であると、含有量が少なすぎるため導電性ポリマーの含有効果が得られにくく、含有量が１０質量％を超えると、正極中の酸性度が高くなることでサイクル特性の向上に繋がらなかったものと考えられる。
したがって、表１の結果から、導電性ポリマーの添加量が０．１質量％〜１０．０質量％の範囲において効果を示し、０．３質量％〜３．０質量％がより好ましいことがわかった。

From the results of Table 1, when comparing the cycle life with respect to the content of the conductive polymer, the cycle life was highest in Example 1 containing 0.7% by mass of the conductive polymer, and having the lowest content of the conductive polymer. In Example 10 and the most frequent Example 8, the cycle life was not improved as compared with Comparative Example 1. This is because when the content of the conductive polymer is less than 0.1% by mass, the content of the conductive polymer is too small to obtain the effect of containing the conductive polymer. When the content exceeds 10% by mass, It is thought that the increase in acidity did not lead to improvement in cycle characteristics.
Therefore, the results in Table 1 show that the addition amount of the conductive polymer is effective in the range of 0.1% by mass to 10.0% by mass, and 0.3% by mass to 3.0% by mass is more preferable. It was.

(Example 11)
<Preparation of nonaqueous electrolyte storage element>
A positive electrode produced with the formulation shown in Example 1 was used, and a lithium metal foil with a diameter of 16 mm was used for the negative electrode, and an electricity storage device was produced in the same manner as in Example 1.

<Charge / discharge test of nonaqueous electrolyte storage element>
The produced electrical storage element was hold | maintained in a 25 degreeC thermostat, and the charging / discharging test was implemented as conditions (I)-(VIII) shown to the following Table A as a charging / discharging test.
The reference current value was set to 2 mA, and (II) and (VI) were set to 5 times (5C) and 10 times (10C) values of the reference current value only for discharge, and the characteristics at the time of rapid discharge were confirmed.
In (IV) and (VIII), only charging was 5 times (5C) and 10 times (10C) the reference current value, and the characteristics during rapid charging were confirmed.
In (I) to (VIII), charging was a constant current at a cutoff voltage of 5.2 V, discharging was a cutoff voltage of 3.0 V, and a pause of 5 minutes was put between charging and discharging and discharging and charging.
FIG. 1 is a plot of specific capacity under each charge / discharge condition, Table 2 is the tenth discharge capacity at the reference current value of (I), and (II), (IV), (VI), (VIII) corresponding thereto. The third discharge capacity retention rate was shown.

(Example 12)
<Preparation of nonaqueous electrolyte storage element>
Using the positive electrode produced by the formulation shown in Example 4 and using a lithium metal foil with a diameter of 16 mm for the negative electrode, a power storage device was produced in the same manner as in Example 11, and charging / discharging was conducted in the same manner as in Example 11. A test was conducted. The results are shown in Table 2 and FIG.

(Example 13)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, an NMP 50 mass% solution of polypyrrole (SSPY, manufactured by Kaken Sangyo Co., Ltd.) as the carbon powder, the conductive auxiliary agent, the thickener, the binder, and the conductive polymer, Except that the mass ratio was 87.2% by mass: 6.6% by mass: 3.3% by mass: 2.2% by mass: 0.7% by mass, and the slurry was prepared by adding water. In the same manner as in Example 1, electrodes and power storage elements were produced, and in the same manner as in Example 11, a charge / discharge test was performed. The results are shown in Table 2.

(Example 14)
<Preparation of nonaqueous electrolyte storage element>
In Example 1, the carbon powder, the conductive auxiliary agent, the thickener, the binder, and polyaniline sulfonic acid (aquaPASS (registered trademark) -01x, manufactured by Kaken Sangyo Co., Ltd.) as the conductive polymer, Mix in a mass ratio of solid content of 87.2% by mass: 6.6% by mass: 3.3% by mass: 2.2% by mass: 0.7% by mass, and add water to prepare a slurry. A positive electrode and a storage element were produced in the same manner as in Example 1 except that the charge / discharge test was performed in the same manner as in Example 11. The results are shown in Table 2.

(Comparative Example 2)
<Preparation of nonaqueous electrolyte storage element>
Using the positive electrode produced by the prescription shown in Comparative Example 1 and using a lithium metal foil having a diameter of 16 mm for the negative electrode, a power storage device was produced in the same manner as in Example 11, and charging / discharging was conducted in the same manner as in Example 11. A test was conducted. The results are shown in Table 2.

図１及び表２の結果から、導電性ポリマーを添加した実施例１１、１２、１３、及び１４は、導電性ポリマーを未添加の比較例２に比べて、急速充放電した際の放電容量が大きく、容量維持率も高い値を示した。これらの結果は、導電性ポリマーの添加によって、電極の抵抗が低下し、電子及びイオンの移動が容易になったためと考えられる。
また、導電性ポリマーとしてポリピロール、ポリアニリンスルフォン酸を用いた実施例１３及び１４は、導電性ポリマーを未添加の比較例２に比べて、急速充放電した際の放電容量及び容量維持率が向上することがわかった。しかし、その添加効果はＰＥＤＯＴを添加した際と比較して小さいことがわかった。これはポリピロール及びポリアニリンスルフォン酸と比較して、ＰＥＤＯＴは高い導電性を有するためであると考えられる。

From the results of FIG. 1 and Table 2, Examples 11, 12, 13, and 14 to which a conductive polymer was added had a discharge capacity when rapidly charged / discharged compared to Comparative Example 2 to which no conductive polymer was added. It was large and the capacity retention rate was also high. These results are thought to be because the addition of the conductive polymer decreased the resistance of the electrode and facilitated the movement of electrons and ions.
Further, in Examples 13 and 14 using polypyrrole and polyaniline sulfonic acid as the conductive polymer, the discharge capacity and capacity retention rate when rapidly charged / discharged are improved as compared with Comparative Example 2 in which the conductive polymer was not added. I understood it. However, it was found that the effect of addition was small compared to the case where PEDOT was added. This is considered to be because PEDOT has higher conductivity than polypyrrole and polyaniline sulfonic acid.

(Example 15)
<Preparation of nonaqueous electrolyte storage element>
-Production of negative electrode-
Artificial graphite (manufactured by Hitachi Chemical Co., Ltd., MAGD) is used as the negative electrode active material, acetylene black (Denka black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) is used as the conductive additive, and SBR system (EX1215, Denki Kagaku Kogyo Co., Ltd.) is used as the binder. Company), PEDOT / PSS (Clevios (registered trademark) PH500, manufactured by H.C. Starck Co., Ltd.) as the conductive polymer, and carboxymethyl cellulose (Daicel 2200, manufactured by Daicel Chemical Industries, Ltd.) as the thickener, , 90.9% by mass: 4.5% by mass: 2.0% by mass: 0.7% by mass: 1.9% by mass The slurry adjusted to the viscosity was applied to one side of a 18 μm thick copper foil using a doctor blade. The average weight per unit area (mass of carbon active material powder in the coated negative electrode) after drying was 10 mg / cm ² . This was punched out to a diameter of 16 mm to obtain a negative electrode.
What was produced in Example 1 was used for the positive electrode. The separator, non-aqueous electrolyte, and electrode were produced in the same manner as in Example 1.

<Charge / discharge test of nonaqueous electrolyte storage element>
The produced electrical storage element was hold | maintained in the 25 degreeC thermostat, and the charging / discharging test was implemented on the following conditions. In addition, the same automatic battery evaluation apparatus as Example 1 was used for the said charging / discharging test.
The reference current value was set to 2.0 mA, and the battery was charged to a charge end voltage of 5.2V. After the first charge, the battery was discharged to 3.0V. There was a 5-minute pause between charging and discharging and between discharging and charging. This charge / discharge was repeated 10 times. Thereafter, only charging was set to 5 times the reference current value (10 mA), and discharging was performed at a reference current value of 2.0 mA. In all cases, charging was a constant current with a cut-off voltage of 5.2 V, discharge was a cut-off voltage of 3.0 V, and a pause of 5 minutes was inserted between the discharge and the charge. This charge was repeated until the capacity was reduced by 20% or more from the first discharge capacity when the charge was made 5 times the reference current value. Table 3 shows the discharge capacity maintenance rate when the discharge capacity at the 10th time at the reference current value of 2 mA, the discharge capacity at the first time when charging is 5 times the reference current value, and the discharge capacity at that time as 100%. The number of cycles at the time when became 80% or less.

(Example 16)
<Preparation of nonaqueous electrolyte storage element>
-Production of negative electrode-
Artificial graphite (manufactured by Hitachi Chemical Co., Ltd., MAGD) is used as the negative electrode active material, acetylene black (Denka black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) is used as the conductive additive, and SBR system (EX1215, Denki Kagaku Kogyo Co., Ltd.) is used as the binder. Company), and carboxymethyl cellulose (Daicel 2200, manufactured by Daicel Chemical Industries, Ltd.) as a thickener, in terms of solid mass, 90.9% by mass: 4.5% by mass: 2.7% by mass: The slurry which mixed so that it might become 1.9 mass%, added water, and was adjusted to the appropriate viscosity was apply | coated to one side using a doctor blade to the copper foil of thickness 18 micrometers. The average weight per unit area (mass of carbon active material powder in the coated positive electrode) after drying was 10 mg / cm ² . This was punched out to a diameter of 16 mm to obtain a negative electrode.
What was produced in Example 1 was used for the positive electrode. Other than that was carried out similarly to Example 15, and produced and evaluated the electrical storage element. The results are shown in Table 3.

(Comparative Example 3)
<Preparation of nonaqueous electrolyte storage element>
A power storage device was produced and evaluated in the same manner as in Example 15 except that the electrode produced in Comparative Example 1 was used for the positive electrode and the electrode produced in Example 15 was used for the negative electrode. The results are shown in Table 3.

(Comparative Example 4)
<Preparation of nonaqueous electrolyte storage element>
A power storage device was produced and evaluated in the same manner as in Example 15 except that the electrode produced in Comparative Example 1 was used for the positive electrode and the electrode produced in Example 16 was used for the negative electrode. The results are shown in Table 3.

表３の結果から、正極及び負極のいずれにも導電性ポリマーを添加した実施例１５と、正極のみに導電性ポリマーを添加した実施例１６のサイクル寿命は、比較例４と比べて飛躍的に向上していることがわかった。一方、負極のみに導電性ポリマーを添加した比較例３では、大きな添加効果は得られなかった。これは、デュアルカーボン蓄電素子において、各電極にインターカレーションするイオン径は負極よりも正極のほうが大きく、電極劣化は正極の方が顕著であると予想されることから、正極に導電性ポリマーを添加することで、より効果的に電極劣化による導電性の低下を抑制することができるためであると考えられる。

From the results of Table 3, the cycle life of Example 15 in which the conductive polymer was added to both the positive electrode and the negative electrode and Example 16 in which the conductive polymer was added only to the positive electrode were dramatically higher than that of Comparative Example 4. It turns out that it is improving. On the other hand, in Comparative Example 3 in which the conductive polymer was added only to the negative electrode, a large addition effect was not obtained. This is because in a dual carbon energy storage device, the ion diameter intercalated with each electrode is larger in the positive electrode than in the negative electrode, and electrode deterioration is expected to be more remarkable in the positive electrode. By adding, it is considered that it is possible to more effectively suppress a decrease in conductivity due to electrode deterioration.

(Example 17)
<Preparation of nonaqueous electrolyte storage element>
-Production of positive electrode-
For the positive electrode, an electrode film containing 0.7% by mass of a conductive polymer was prepared in the same manner as in Example 1, and an electrode having an average basis weight of 3.0 mg / cm ² was prepared.

-Production of negative electrode-
Lithium titanate (Li ₄ Ti ₅ O ₁₂ , manufactured by Titanium Industry Co., Ltd.) as the negative electrode active material, acetylene black (Denka Black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) as the conductive additive, and styrene butadiene rubber (TRD102A, JSR Co., Ltd.) and carboxymethyl cellulose (Daicel 2200, manufactured by Daicel Chemical Industries, Ltd.) as a thickener are mixed in a mass ratio of solids of 100: 7: 3: 1, and water. Was applied to one side of a 18 μm thick aluminum foil using a doctor blade. The average basis weight after drying was 3.0 mg / cm ² . Thus, a negative electrode was produced.

-Production of electricity storage elements-
2 mol / L LiPF ₆ dimethyl carbonate (DMC): ethylene carbonate (EC): fluoroethylene carbonate (FEC) = (96 mass%: 2 mass%: 2 mass%) mixed solution (Kishida Chemical Co., Ltd.) in non-aqueous electrolyte A power storage device was produced in the same manner as in Example 1 except that the product manufactured by the company was used.

<Charge / discharge test of nonaqueous electrolyte storage element>
The reference current value was 0.5 mA, and the battery was charged to a charge end voltage of 3.7 V.
After the first charge, the battery was discharged to 1.5 V (since lithium titanate has an operating potential of 1.5 V (vsLi / Li ⁺ )). There was a 5-minute pause between charging and discharging and between discharging and charging. This charge / discharge was repeated 10 times. Thereafter, only charging was performed at 5 times the reference current value (2.5 mA), and discharging was performed at a reference current value of 0.5 mA. In all cases, charging was a constant current at a cutoff voltage of 3.7 V, discharging was a constant current at a cutoff voltage of 1.5 V, and a pause of 5 minutes was inserted between discharging and charging. This charge was repeated until the capacity was reduced by 20% or more from the first discharge capacity when the charge was made 5 times the reference current value.
Table 4 shows the discharge capacity when the discharge capacity at the 10th time at the reference current value of 0.5 mA, the discharge capacity at the first time when charging is 5 times the reference current value, and the discharge capacity at that time as 100%. The number of cycles when the maintenance rate became 80% or less is shown.

(Example 18)
<Preparation of nonaqueous electrolyte storage element>
The positive electrode was the same as in Example 17 except that an electrode film containing 1.1% by mass of a conductive polymer was prepared in the same formulation as in Example 3, and an electrode having an average basis weight of 3.0 mg / cm ² was prepared. A negative electrode and a power storage element were produced by the method and evaluated. The results are shown in Table 4.

(Comparative Example 5)
<Preparation of nonaqueous electrolyte storage element>
The positive electrode was prepared in the same manner as in Comparative Example 1 except that an electrode film containing no conductive polymer was prepared, and an electrode having an average basis weight of 3.0 mg / cm ² was prepared. And the electrical storage element was produced and evaluated. The results are shown in Table 4.

表４の結果から、負極にチタン酸リチウム（ＬＴＯ）を用いた場合においても、導電性ポリマーを添加した実施例１７及び１８は、導電性ポリマーを未添加の比較例５に比べて、サイクル寿命の向上が認められた。

From the results of Table 4, even when lithium titanate (LTO) was used for the negative electrode, Examples 17 and 18 to which a conductive polymer was added were more cycle life than Comparative Example 5 to which no conductive polymer was added. Improvement was observed.

  From the above results, a non-aqueous electrolyte storage element with high discharge capacity and excellent cycle characteristics and rapid charge / discharge characteristics utilizing anion insertion into the positive electrode by adding a conductive polymer as a constituent material of the electrode It was found that can provide.

Aspects of the present invention are as follows, for example.
<1> A non-aqueous electrolyte storage element having a positive electrode including a positive electrode active material capable of inserting or removing anions, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte,
The positive electrode contains a conductive polymer, and is a nonaqueous electrolyte storage element.
<2> The nonaqueous electrolysis according to <1>, wherein the content of the conductive polymer is 0.1% by mass to 10% by mass with respect to the total amount of the positive electrode material excluding the positive electrode current collector from the positive electrode. It is a liquid storage element.
<3> Any of <1> to <2>, wherein the content of the conductive polymer is 0.3% by mass to 3% by mass with respect to the total amount of the positive electrode material excluding the positive electrode current collector from the positive electrode It is a non-aqueous electrolyte storage element as described above.
<4> The nonaqueous electrolyte storage element according to any one of <1> to <3>, wherein the negative electrode contains a conductive polymer.
<5> Any of <1> to <4>, wherein the conductive polymer is a mixture of poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (4-styrenesulfonic acid) (PSS) It is a non-aqueous electrolyte storage element as described above.
<6> The nonaqueous electrolyte storage element according to any one of <1> to <5>, wherein the negative electrode includes a negative electrode active material capable of occluding or releasing at least one of metallic lithium and lithium ions. It is.
<7> The nonaqueous electrolyte storage element according to any one of <1> to <6>, wherein the positive electrode active material is a carbonaceous material.
<8> The nonaqueous electrolyte storage element according to any one of <1> to <7>, wherein the negative electrode active material is a carbonaceous material.
<9> The nonaqueous electrolyte storage element according to any one of <1> to <8>, wherein the nonaqueous electrolyte is obtained by dissolving a lithium salt in a nonaqueous solvent.
<10> The lithium salt is a nonaqueous electrolytic capacitor element according to the a LiPF ₆ <9>.

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Exterior can 5 Negative electrode lead wire 6 Positive electrode lead wire 10 Nonaqueous electrolyte storage element

Japanese Patent No. 4098505

Claims (10)

A non-aqueous electrolyte storage element having a positive electrode including a positive electrode active material capable of inserting or removing anions, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte,
The non-aqueous electrolyte storage element, wherein the positive electrode contains a conductive polymer.   The nonaqueous electrolyte storage element according to claim 1, wherein the content of the conductive polymer is 0.1% by mass to 10% by mass with respect to the total amount of the positive electrode material excluding the positive electrode current collector from the positive electrode.   3. The non-aqueous solution according to claim 1, wherein the content of the conductive polymer is 0.3% by mass to 3% by mass with respect to the total amount of the positive electrode material excluding the positive electrode current collector from the positive electrode. Electrolyte storage element.   The non-aqueous electrolyte storage element according to claim 1, wherein the negative electrode contains a conductive polymer.   The non-aqueous solution according to any one of claims 1 to 4, wherein the conductive polymer is a mixture of poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (4-styrenesulfonic acid) (PSS). Electrolyte storage element.   The non-aqueous electrolyte storage element according to claim 1, wherein the negative electrode is a negative electrode including a negative electrode active material capable of occluding or releasing at least one of metallic lithium and lithium ions.   The non-aqueous electrolyte storage element according to claim 1, wherein the positive electrode active material is a carbonaceous material.   The non-aqueous electrolyte storage element according to claim 1, wherein the negative electrode active material is a carbonaceous material.   The nonaqueous electrolyte storage element according to claim 1, wherein the nonaqueous electrolyte is obtained by dissolving a lithium salt in a nonaqueous solvent. The non-aqueous electrolyte storage element according to claim 9, wherein the lithium salt is LiPF ₆ .

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