JP6736833B2 - Non-aqueous electrolyte storage element - Google Patents

Description

The present invention relates to a non-aqueous electrolyte storage element in which an anion is inserted into a positive electrode and a cation is inserted into or released from a negative electrode.

In recent years, with the miniaturization and higher performance of mobile devices, the characteristics of non-aqueous electrolyte storage elements with high energy density have been improved and are becoming widespread. Is being developed, and it is being installed in electric vehicles.

Such a non-aqueous electrolyte storage element is composed of a positive electrode such as a lithium cobalt composite oxide, a carbon negative electrode, and a non-aqueous electrolytic solution obtained by dissolving a lithium salt in a non-aqueous solvent. Lithium ion secondary batteries are often used in which lithium is desorbed and inserted into the carbon of the negative electrode, and during discharge, the lithium inserted in the negative electrode is desorbed and returns to the composite oxide of the positive electrode to be charged and discharged. ..

On the other hand, when the power storage device is used in a hybrid vehicle, it is essential that a large current can be instantaneously output, and it is desirable that the power storage device can be charged with regenerative energy. Therefore, an electric double layer capacitor that does not require a chemical reaction and can be charged and discharged at high speed is used. However, compared with the lithium-ion power storage element, the energy density is several tenths, and a heavy power storage element is required to secure a sufficient capacity, which hinders improvement of fuel consumption when loaded in an automobile.

As a power storage element having a high energy density and suitable for high-speed charging/discharging, a conductive polymer, a carbon material or the like is used as a positive electrode, a negative electrode such as carbon, and a non-aqueous electrolyte solution obtained by dissolving a lithium salt in a non-aqueous solvent. When charging, the anions in the non-aqueous electrolyte are inserted into the positive electrode and the cations are inserted into the negative electrode, and during discharge, the anions and cations inserted in the positive electrode and the negative electrode are desorbed into the electrolytic solution. It is expected that a so-called dual intercalation type non-aqueous electrolyte storage element, which is charged and discharged by means of the above, will be put to practical use.

When LiPF ₆ is used as the lithium salt, as shown in the following reaction formula, PF ₆ ⁻ is inserted into the positive electrode and Li ⁺ is inserted into the negative electrode from the nonaqueous electrolytic solution, whereby charging is performed. Discharge is performed by desorbing PF ₆ ^{− from} the positive electrode and Li ⁺ from the negative electrode into the nonaqueous electrolytic solution.

It is known that graphite is used as an active material that stores and releases anions, as in Patent Documents 1 to 3.
When graphite is used as the positive electrode active material, as described in Patent Document 1 (Japanese Patent No. 4392169), the end-of-charge voltage is set to 5.3 to 5.6 V with respect to the lithium reference electrode, thereby increasing the capacity. It is known that a secondary battery can be obtained. Patent Document 2 (Japanese Patent No. 4314087) describes that a secondary battery having excellent cycle characteristics can be obtained by using borated graphite, and Patent Document 3 (Japanese Patent No. 4569126) discloses high-speed discharge. particularly negative for obtaining the properties, metallic lithium, or BET specific surface area of at 0.5m ² /g~25.0m ² / g, it is disclosed that the use of carbonaceous material having a particle size 1μm~100μm However, according to the studies by the present inventors, when graphite is used for the positive electrode, the capacity cannot be sufficiently increased.

WO 2008-123606 of Patent Document 4 discloses a porous carbon material using a plant-derived material as a raw material, which is obtained by carbonizing the plant-derived material at 800°C to 1400°C and then treating it with an acid or an alkali. It is described that a porous carbon material for an electrode can be obtained from a plant-derived material having a silicon content of 10% by weight or more as a raw material by the manufacturing method, but this technique relates to a fuel cell. It does not relate to secondary batteries, and the obtained porous carbon material is a poorly porous carbon material having a specific surface area by nitrogen BET method of 10 m2/g and a pore volume of 0.1 cm3/g. is there.
WO 2011-065484 of Patent Document 5 describes a battery having an electric double layer capacitor in which a carbon porous material having a specific surface area of 200 to 3000 m ² /g is used for an electrode, but this technique is also used. The melamine monomer, which is a raw material of the melamine resin, is related to the fuel cell, not to the secondary battery, based on the recognition that the nitrogen-containing carbon material is more suitable as the electrode material for EDLC of the fuel cell. Since it is sublimated by heat treatment, it cannot be directly used as a raw material of the nitrogen-containing porous carbon material, and it is intended to overcome the difficulty of easily producing the nitrogen-containing porous carbon material. Only.

The present invention has been made in view of the above prior art, and an object thereof is to provide a non-aqueous electrolyte storage element having a high energy density.

The means for solving the above problems are as follows. That is, the above-mentioned object of the present invention is solved by the “non-aqueous electrolyte storage element” described in (1) below.
(1) “A positive electrode containing a positive electrode active material capable of inserting or releasing anions, a negative electrode containing a negative electrode active material, a non-aqueous solvent, an electrolyte salt containing a halogen atom, and a site capable of binding an anion containing a halogen atom. And a non-aqueous electrolyte solution containing a compound having ##STR3## wherein the carbon active material used as the positive electrode active material has continuous mesopores having a three-dimensional network structure and having a pore diameter of 2 nm or more. A non-aqueous electrolyte storage element characterized by being amorphous porous carbon".

As will be apparent from the detailed and specific description below, according to the present invention, it is possible to provide (1) an electricity storage device having a specific capacity equal to or higher than that of graphite, and (2) use insertion of anions into a positive electrode. It is possible to provide a high-capacity electricity storage element, (3) a high-concentration electrolyte solution can be used, and the energy density of the cell can be increased.

It is the figure which showed what plotted the value of the discharge capacity and the discharge current value in an Example and a comparative example.

Hereinafter, the present invention will be described in detail. The present invention relates to the “non-aqueous electrolyte storage element” having the configuration described in (1) above, but this “non-aqueous electrolyte storage element” will be understood from the detailed description below. In addition, since the "non-aqueous electrolyte storage element" of the embodiments described in (2) to (4) below is also included, these will also be described in detail.
(2) “The porous carbon has a BET specific surface area value of 500 to 2000 m ² /g, a mesopore diameter value of 2 to 200 nm, and a micropore volume of 0.01 to 1.00 mL/g. The non-aqueous electrolyte storage element described in (1).
(3) "The non-aqueous electrolyte storage element according to (1) or (2) above, wherein the negative electrode active material is also a bipolar carbon secondary battery made of a carbonaceous material."
(4) "The non-aqueous electrolysis according to any one of (1) to (3), wherein the carbon active material used for the positive electrode active material is one that intercalates PF ₆ ions. Liquid storage element."

[Configuration of non-aqueous electrolyte storage element]
(1. Positive electrode)
The positive electrode is not particularly limited as long as it contains a positive electrode electricity storage material (such as a positive electrode active material), and can be appropriately selected according to the purpose. For example, a positive electrode material having a positive electrode active material on a positive electrode current collector is used. A positive electrode provided therewith and the like can be mentioned.
The shape of the positive electrode is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a flat plate shape.

(1-1. Positive electrode material)
The positive electrode material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the positive electrode material may include at least a positive electrode active material, and further may include a conductive additive, a binder, a thickener, and the like. Become.

(1) Positive Electrode Active Material As the positive electrode active material, amorphous porous carbon in which the carbon active material has pores (mesopores) having a pore diameter of 2 nm or more and having a continuous three-dimensional network structure is used. The "positive electrode active material having a continuous three-dimensional network structure having mesopores having a pore diameter of 2 nm or more" has positive and negative electrolyte ions paired on both sides of the surface where the mesopores (cavities) are in contact with the carbon material portion. electrostatic loading layer by present are Ru is formed.
As for amorphous porous carbon, the time constant of the capacitor (slow response during charging/discharging) depends not only on the capacitance of the non-aqueous electrolyte but also on the resistance value of the carbon material portion in ohmic contact therewith. Due to Furthermore, since both electrolyte ions are involved in a chemical reaction in which bond-separation is repeated with a polar active material for each, it is possible to consider that it is preferable that there are many sites therefor.

In porous carbon, mesopores are essential, but micropores are not. Therefore, although micropores may or may not be present, organic substances as a carbon material forming source usually emit volatile substances during carbonization and carbonize, and therefore, usually micropores are left as traces of emission. It is difficult to use the one without micropores because it leaves. In contrast, mesopores are usually formed intentionally. For example, as is known, an acid (alkali)-soluble metal, for example, a metal oxide or metal salt such as SiO ₂ , a skeleton of a metal-containing organic material, and a carbon material or an organic material as a raw material thereof are molded together. After that, traces of the skeleton part dissolved away with an acid (or alkali) often become mesopores.
Here, in the present specification, those having a pore size of less than 2 nm are referred to as micropores, and those having a pore size of 2 to 50 nm are referred to as mesopores. Since the size of the electrolyte ion is 0.5 nm to 2 nm, it is hard to say that the micropores contribute a lot to the migration of ions. Therefore, mesopores are important for the smooth migration of ions. By the way, the pore size in activated carbon, which is the same carbonaceous material, is said to be about 1 nm on average, and in the case of activated carbon, it is regarded as one of all adsorptions accompanied by heat generation (decrease in enthalpy) without exception.
It is desirable that the mesopores of the above size form a three-dimensional network structure. The three-dimensional network structure is a structure in which mesopores are three-dimensionally connected. If the mesopores have a three-dimensional network structure, the ions move smoothly.

The specific surface area is preferably 500 m ² /g or more.
When the specific surface area is less than 500 m ² /g, the amount of pores formed is insufficient, ions are not sufficiently inserted, and the capacity cannot be increased.
On the other hand, it is desirable that the specific surface area is 2000 m ² /g or less. When the specific surface area exceeds 2000 m ² /g, the mesopores are not sufficiently formed, and the ion insertion is hindered, so that the capacity cannot be increased.
The mesopores are open pores, and it is necessary that the mesopores have continuous pores. With the above configuration, the ions move smoothly.
The volume of the micropores is preferably 1.00 ml/g or less.
If the volume of the micropores exceeds 1.00 ml/g, the intercalation and desorption of ions may be hindered and the capacity may be reduced.
It should be noted that such porous carbon is known as a material per se, and therefore, detailed description of a method for obtaining the same (for example, a manufacturing method) for carrying out the present invention is omitted here.
For example, in JP 2001-229914 A, it is obtained by firing a thermoplastic resin such as polyvinyl chloride, polyvinyl alcohol, or polyvinylpyrrolidone, and in thermogravimetric measurement (TG), it is elevated in an air stream of 200 ml/min. When the temperature is raised at a temperature rate of 20° C./min, the starting temperature for weight loss in the first stage is 350 to 600° C., and the amount of weight loss in the first stage is 3 to 20 of the weight before raising temperature % Amorphous carbon coating is described. However, this publication only describes that this film is used as a negative electrode active material of a lithium ion secondary battery (LiB) in which only Li ions move between the electrode and the electrolyte, as in the conventional case. It does not suggest that both ionic and negative ions be used as a positive electrode active material of a bipolar carbon secondary battery (DCB) that moves between both electrodes and an electrolyte.
In other words, in the present invention, a large size negative ion such as PF _{6 −} ion can enter from the mesopores of the carbon active material as the positive electrode active material and intercalate into the carbon active material. It means that it is a thing.

(2) Binder and Thickener The binder and the thickener are not particularly limited as long as they are materials that are stable with respect to the solvent and electrolytic solution used at the time of manufacturing the electrode, and the potential applied, and depending on the purpose. Can be appropriately selected by, for example, polyvinylidene fluoride (PVDF), fluorine binder such as polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber. , Acrylate latex, carboxymethyl cellulose (CMC), methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, starch starch, casein, and the like. These may be used alone or in combination of two or more. Among these, polyvinylidene fluoride (PVDF), fluorine binders such as polytetrafluoroethylene (PTFE), acrylate latex, and carboxymethyl cellulose (CMC) are preferable.

(3) Conductivity Auxiliary Agent Examples of the conductivity auxiliary agent include metal materials such as copper and aluminum, carbonaceous materials such as carbon black, acetylene black, and carbon nanotubes. These may be used alone or in combination of two or more.

(1-2. Positive electrode current collector)
The material, shape, size and structure of the positive electrode current collector are not particularly limited and can be appropriately selected according to the purpose.
The material for 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 stainless steel, nickel, aluminum, titanium, tantalum, and the like. Among these, stainless steel and aluminum are particularly preferable.
The shape of the positive electrode current collector is not particularly limited and may be appropriately selected depending on the purpose.
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 depending on the purpose.

(1-3. Method for producing positive electrode)
The positive electrode is formed by adding the binder, the thickening agent, the conductive agent, a solvent and the like to the positive electrode active material as a slurry to form a positive electrode material on the positive electrode current collector, followed by drying. It can be manufactured. The solvent is appropriately selected depending on the intended purpose without any limitation, and examples thereof include an aqueous solvent and an organic solvent. Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP) and toluene.
The positive electrode active material may be directly roll-formed into a sheet electrode, or may be compression-formed into a pellet electrode.

(2. Negative electrode)
The negative electrode is not particularly limited as long as it contains a negative electrode active material, and can be appropriately selected depending on the purpose, for example, a negative electrode including a negative electrode material having a negative electrode active material on a negative electrode current collector, and the like. Can be mentioned.
The shape of the negative electrode is appropriately selected depending on the intended purpose without any limitation, and examples thereof include a flat plate shape.

(2-1. Negative electrode material)
The negative electrode material contains at least a negative electrode electricity storage material (negative electrode active material, etc.), and further contains a conductive auxiliary agent, a binder, a thickener, etc., if necessary.

(1) Negative Electrode Active Material The negative electrode active material is not particularly limited as long as it is a substance that absorbs and desorbs lithium ions in at least a non-aqueous solvent system, and specifically, carbonaceous material, antimony tin oxide, monoxide. Metal oxides capable of occluding and releasing lithium such as silicon, metals or metal alloys capable of alloying with lithium such as aluminum, tin, silicon and zinc, metals capable of alloying with lithium, alloys containing the metal and lithium. And the like, and lithium metal nitride such as lithium cobalt nitride. These may be used alone or in combination of two or more. Among these, carbonaceous materials are particularly preferable from the viewpoint of safety and cost.
Examples of the carbonaceous material include coke, artificial graphite, graphite such as natural graphite, and thermally decomposed products of organic substances under various thermal decomposition conditions. Among these, artificial graphite and natural graphite are particularly preferable.

(2) Binder and Thickening Agent The binder and the thickening agent are not particularly limited as long as they are materials that are stable to the solvent and electrolytic solution used at the time of manufacturing the electrode, and the potential applied, and are appropriately selected depending on the purpose. It can be selected, for example, polyvinylidene fluoride (PVDF), a fluorine-based binder such as polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber, acrylate. Examples thereof include system latex, carboxymethyl cellulose (CMC), methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, starch phosphate, and casein. These may be used alone or in combination of two or more. Among these, fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) are preferable.

(3) Conductivity Auxiliary Agent Examples of the conductivity auxiliary agent include metal materials such as copper and aluminum, carbonaceous materials such as carbon black, acetylene black, and carbon nanotubes. These may be used alone or in combination of two or more.

2-2. Negative Electrode Current Collector The material, shape, size and structure of the negative electrode current collector are not particularly limited and can be appropriately selected according to the purpose.
The material of the negative electrode current collector is made 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. Steel, nickel, aluminum, copper, etc. are mentioned. Among these, stainless steel, copper and aluminum are particularly preferable.
The shape of the current collector is not particularly limited and may be appropriately selected depending on the purpose.
The size of the 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.

2-3. Negative Electrode Preparation Method The negative electrode is formed by adding the binder and the thickening agent, the conductive agent, a solvent, and the like to the negative electrode active material as a slurry to form a negative electrode material on the negative electrode current collector. Then, it can be manufactured by drying. As the solvent, the same solvent as used in the method for producing the positive electrode can be used.
Further, by adding the binder and the thickener, the conductive agent and the like to the negative electrode active material to form a sheet electrode by roll molding as it is, or a pellet electrode by compression molding, by vapor deposition, sputtering, plating, etc. A thin film of the negative electrode active material may be formed on the negative electrode current collector.

(3. Non-aqueous electrolyte)
The non-aqueous electrolytic solution is an electrolytic solution obtained by dissolving an electrolyte salt in a non-aqueous solvent.

(3-1. Non-aqueous solvent)
The non-aqueous solvent is appropriately selected depending on the intended purpose without any limitation, but it is preferably an aprotic organic solvent.
As the aprotic organic solvent, a carbonate-based organic solvent such as a chain carbonate or a cyclic carbonate is used, and a low-viscosity solvent is preferable. Among these, chain carbonates are preferable from the viewpoint of high solubility of the electrolyte salt.

Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and the like. Of these, dimethyl carbonate (DMC) is preferable.
The content of the DMC is appropriately selected depending on the intended purpose without any limitation, but it is preferably 70% by mass or more and more preferably 83% by mass or more with respect to the non-aqueous solvent. When 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 having a high dielectric constant (such as a cyclic carbonate or a cyclic ester). When a high-concentration non-aqueous electrolytic solution of 3 M or more is prepared, the viscosity becomes too high, and the non-aqueous electrolytic solution may impregnate the electrode or cause a problem in terms of ion diffusion.

Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), and the like.
When a mixed solvent of 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 There is no limitation and it can be appropriately selected according to the purpose, but the mass ratio (EC:DMC) is preferably from 3:10 to 1:99, more preferably from 3:10 to 1:20.

As the non-aqueous solvent, if necessary, 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, and the like can be used.
Examples of the cyclic ester include γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone, and the like.
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.), etc. Are listed.
Examples of the cyclic ether include tetrahydrofuran, alkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, and 1,4-dioxolane.
Examples of the chain ether include 1,2-dimethoxyethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether, and the like.

(3-2. Electrolyte salt)
A lithium salt is used as the electrolyte salt. There is no particular limitation as long as it dissolves in a non-aqueous solvent and exhibits high ionic conductivity, and examples thereof include lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium chloride (LiCl), and borofluoride. Lithium (LiBF4), lithium arsenide hexafluoride (LiAsF6), lithium trifluorometasulfonate (LiCF3SO3), lithium bistrifluoromethylsulfonylimide (LiN(C2F5SO2)2), lithium bis-furfluoroethylsulfonyl imide (LiN(CF2F5SO2)). 2), and the like. These may be used alone or in combination of two or more. Among these, LiPF6 is particularly preferable from the viewpoint of the amount of storage of anions in the carbon electrode.
The concentration of the electrolyte salt is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5 mol/L to 6 mol/L in the non-aqueous solvent and is compatible with battery capacity and output. From this point, 2 mol/L to 4 mol/L is more preferable.

(4. Separator)
The separator is provided between the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode.
The material, shape, size and structure of the separator are not particularly limited and may be appropriately selected depending on the purpose.
Examples of the material of the separator include kraft paper, vinylon mixed paper, paper such as synthetic pulp mixed paper, cellophane, polyethylene graft membrane, polyolefin nonwoven fabric such as polypropylene meltblown 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 retaining an electrolytic solution. As a shape, a non-woven fabric type is preferable since it has a higher porosity than a thin film type having micropores (micropores). The thickness is preferably 20 μm or more from the viewpoint of preventing short circuit and retaining the electrolytic solution.
The size of the separator 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.
The structure of the separator may be a single layer structure or a laminated structure.

(5. Method for manufacturing non-aqueous electrolyte storage element)
The non-aqueous electrolyte storage element of the present invention is manufactured by assembling the positive electrode, the negative electrode, the non-aqueous electrolyte, and a separator used as necessary into an appropriate shape. Further, other constituent members such as a battery outer can can be used if necessary. The method for assembling the non-aqueous electrolyte storage element is not particularly limited, and can be appropriately selected from the methods usually adopted.
The shape of the non-aqueous electrolyte storage element of the present invention is not particularly limited, and can be appropriately selected from various commonly used shapes according to the application. Examples of the shape include a cylinder type in which a sheet electrode and a separator are formed in a spiral shape, a cylinder type in which an inside-out structure is formed by combining a pellet electrode and a separator, and a coin type in which pellet electrodes and a separator are stacked.

(6. Use)
The use of the non-aqueous electrolyte storage element of the present invention is not particularly limited and can be used for various purposes, for example, notebook personal computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, mobile fax, mobile phone. Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini disk, transceiver, electronic organizer, calculator, memory card, portable tape recorder, radio, backup power supply, motor, lighting equipment, toys, games Devices, clocks, strobes, cameras, etc.
Examples of the conductive aid include metal materials such as copper and aluminum, carbonaceous materials such as carbon black, acetylene black, and carbon nanotubes. These may be used alone or in combination of two or more.

(1-2. Positive electrode current collector)
The material, shape, size and structure of the positive electrode current collector are not particularly limited and can be appropriately selected according to the purpose.
The material for 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 stainless steel, nickel, aluminum, titanium, tantalum, and the like. Among these, stainless steel and aluminum are particularly preferable.
The shape of the positive electrode current collector is not particularly limited and may be appropriately selected depending on the purpose.
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 depending on the purpose.

(1-3. Method for producing positive electrode)
The positive electrode is formed by adding the binder, the thickening agent, the conductive agent, a solvent and the like to the positive electrode active material as a slurry to form a positive electrode material on the positive electrode current collector, followed by drying. It can be manufactured. The solvent is appropriately selected depending on the intended purpose without any limitation, and examples thereof include an aqueous solvent and an organic solvent. Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP) and toluene.
The positive electrode active material may be directly roll-formed into a sheet electrode, or may be compression-formed into a pellet electrode.

(2. Negative electrode)
The negative electrode is not particularly limited as long as it contains a negative electrode active material, and can be appropriately selected depending on the purpose, for example, a negative electrode including a negative electrode material having a negative electrode active material on a negative electrode current collector, and the like. Can be mentioned.
The shape of the negative electrode is appropriately selected depending on the intended purpose without any limitation, and examples thereof include a flat plate shape.

(2-1. Negative electrode material)
The negative electrode material contains at least a negative electrode electricity storage material (negative electrode active material, etc.), and further contains a conductive auxiliary agent, a binder, a thickener, etc., if necessary.

(1) Negative Electrode Active Material The negative electrode active material is not particularly limited as long as it is a substance that absorbs and desorbs lithium ions in at least a non-aqueous solvent system, and specifically, carbonaceous material, antimony tin oxide, monoxide. Metal oxides capable of occluding and releasing lithium such as silicon, metals or metal alloys capable of alloying with lithium such as aluminum, tin, silicon and zinc, metals capable of alloying with lithium, alloys containing the metal and lithium. And the like, and lithium metal nitride such as lithium cobalt nitride. These may be used alone or in combination of two or more. Among these, carbonaceous materials are particularly preferable from the viewpoint of safety and cost.
Examples of the carbonaceous material include coke, artificial graphite, graphite such as natural graphite, and thermally decomposed products of organic substances under various thermal decomposition conditions. Among these, artificial graphite and natural graphite are particularly preferable.

(2) Binder and Thickening Agent The binder and the thickening agent are not particularly limited as long as they are materials that are stable to the solvent and electrolytic solution used at the time of manufacturing the electrode, and the potential applied, and are appropriately selected depending on the purpose. It can be selected, for example, polyvinylidene fluoride (PVDF), a fluorine-based binder such as polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber, acrylate. Examples thereof include system latex, carboxymethyl cellulose (CMC), methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, starch phosphate, and casein. These may be used alone or in combination of two or more. Among these, fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) are preferable.

(3) Conductivity Auxiliary Agent Examples of the conductivity auxiliary agent include metal materials such as copper and aluminum, carbonaceous materials such as carbon black, acetylene black, and carbon nanotubes. These may be used alone or in combination of two or more.

2-2. Negative Electrode Current Collector The material, shape, size and structure of the negative electrode current collector are not particularly limited and can be appropriately selected according to the purpose.
The material of the negative electrode current collector is made 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. Steel, nickel, aluminum, copper, etc. are mentioned. Among these, stainless steel, copper and aluminum are particularly preferable.
The shape of the current collector is not particularly limited and can be appropriately selected depending on the purpose.
The size of the 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.

2-3. Negative Electrode Preparation Method The negative electrode is formed by adding the binder and the thickening agent, the conductive agent, a solvent, and the like to the negative electrode active material as a slurry to form a negative electrode material on the negative electrode current collector. Then, it can be manufactured by drying. As the solvent, the same solvent as used in the method for producing the positive electrode can be used.
Further, by adding the binder and the thickener, the conductive agent and the like to the negative electrode active material to form a sheet electrode by roll molding as it is, or a pellet electrode by compression molding, by vapor deposition, sputtering, plating, etc. A thin film of the negative electrode active material may be formed on the negative electrode current collector.

(3. Non-aqueous electrolyte)
The non-aqueous electrolytic solution is an electrolytic solution obtained by dissolving an electrolyte salt in a non-aqueous solvent.

(3-1. Non-aqueous solvent)
The non-aqueous solvent is appropriately selected depending on the intended purpose without any limitation, but it is preferably an aprotic organic solvent.
As the aprotic organic solvent, a carbonate-based organic solvent such as a chain carbonate or a cyclic carbonate is used, and a low-viscosity solvent is preferable. Among these, chain carbonates are preferable from the viewpoint of high solubility of the electrolyte salt.

Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and the like. Of these, dimethyl carbonate (DMC) is preferable.
The content of the DMC is appropriately selected depending on the intended purpose without any limitation, but it is preferably 70% by mass or more and more preferably 83% by mass or more with respect to the non-aqueous solvent. When 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 having a high dielectric constant (such as a cyclic carbonate or a cyclic ester). When a high-concentration non-aqueous electrolytic solution of 3 M or more is prepared, the viscosity becomes too high, and the non-aqueous electrolytic solution may impregnate the electrode or cause a problem in terms of ion diffusion.

Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), and the like.
When a mixed solvent of 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 There is no limitation and it can be appropriately selected according to the purpose, but the mass ratio (EC:DMC) is preferably from 3:10 to 1:99, more preferably from 3:10 to 1:20.

As the non-aqueous solvent, if necessary, 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, and the like can be used.
Examples of the cyclic ester include γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone, and the like.
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.), etc. Are listed.
Examples of the cyclic ether include tetrahydrofuran, alkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, and 1,4-dioxolane.
Examples of the chain ether include 1,2-dimethoxyethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether, and the like.

(3-2. Electrolyte salt)
A lithium salt is used as the electrolyte salt. There is no particular limitation as long as it dissolves in a non-aqueous solvent and exhibits high ionic conductivity, and examples thereof include lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), and borohydride. Lithium fluoride (LiBF ₄ ), lithium arsenide hexafluoride (LiAsF ₆ ), lithium trifluorometasulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide (LiN(C ₂ F ₅ SO ₂ ) ₂ ), lithium bis fur fluoroethyl imide _{(LiN (CF 2 F 5 SO} 2) 2), and the like. These may be used alone or in combination of two or more. Among these, LiPF ₆ is particularly preferable from the viewpoint of the amount of storage of anions in the carbon electrode.
The concentration of the electrolyte salt is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5 mol/L to 6 mol/L in the non-aqueous solvent and is compatible with battery capacity and output. From this point, 2 mol/L to 4 mol/L is more preferable.

(4. Separator)
The separator is provided between the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode.
The material, shape, size and structure of the separator are not particularly limited and may be appropriately selected depending on the purpose.
Examples of the material of the separator include kraft paper, vinylon mixed paper, paper such as synthetic pulp mixed paper, cellophane, polyethylene graft membrane, polyolefin nonwoven fabric such as polypropylene meltblown 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 retaining an electrolytic solution. As a shape, a non-woven fabric type is preferable since it has a higher porosity than a thin film type having micropores (micropores). The thickness is preferably 20 μm or more from the viewpoint of preventing short circuit and retaining the electrolytic solution.
The size of the separator 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.
The structure of the separator may be a single layer structure or a laminated structure.

(5. Method for manufacturing non-aqueous electrolyte storage element)
The non-aqueous electrolyte storage element of the present invention is manufactured by assembling the positive electrode, the negative electrode, the non-aqueous electrolyte, and a separator used as necessary into an appropriate shape. Further, other constituent members such as a battery outer can can be used if necessary. The method for assembling the non-aqueous electrolyte storage element is not particularly limited, and can be appropriately selected from the methods usually adopted.
The shape of the non-aqueous electrolyte storage element of the present invention is not particularly limited, and can be appropriately selected from various commonly used shapes according to the application. Examples of the shape include a cylinder type in which a sheet electrode and a separator are formed in a spiral shape, a cylinder type in which an inside-out structure is formed by combining a pellet electrode and a separator, and a coin type in which pellet electrodes and a separator are stacked.

(6. Use)
The use of the non-aqueous electrolyte storage element of the present invention is not particularly limited and can be used for various purposes, for example, notebook personal computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, mobile fax, mobile phone. Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini disk, transceiver, electronic organizer, calculator, memory card, portable tape recorder, radio, backup power supply, motor, lighting equipment, toys, games Devices, 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]
Carbon A (manufactured by Toyo Tanso Co., Ltd.) as a positive electrode active material, acetylene black (Denka Black powder: Denki Kagaku Kogyo) as a conduction aid, acrylate latex (TRD202A:JSR) as a binder, and carboxymethyl cellulose (Daicel 2200: as a thickener). Daicel Chemical Industries, Ltd.) were mixed so that the weight ratio of solids was 100:7.6:5:4, and water was added to the slurry to adjust the viscosity to a 20 μm thick aluminum foil. It was applied to one side using a doctor blade. The average basis weight after drying was 1.2 mg/cm ² . This was punched out to a diameter of 16 mm to obtain a positive electrode.
As the separator, two glass filter papers (gA100: ADVANTEC) punched out to φ16 mm were used, and a lithium metal foil of φ16 mm was used for the negative electrode.
As the electrolytic solution, a 2 mol/L LiPF6 DMC solution was used.

<Battery preparation and measurement>
After vacuum drying the above positive electrode and separator at 150° C. for 4 hours, a 2032 type coin cell was assembled in a dry argon glove box.
The prepared electricity storage device was held in a constant temperature bath at 25° C., and a charge/discharge test was carried out under the following conditions. The reference current value was 0.3 mA. Further, in all cases, the cutoff voltage was 5.2 V for charging, a constant current was used for discharging, and the cutoff voltage was 3.0 V for discharging, and a pause of 5 minutes was inserted between charging and discharging and discharging and charging.
Charge/discharge test conditions; charge 2mA discharge 2mA 10 times

[Example 2]
Carbon B (manufactured by Toyo Tanso Co., Ltd.) as a positive electrode active material, acetylene black (Denka Black powder: Denki Kagaku Kogyo) as a conduction aid, acrylate latex (TRD202A:JSR) as a binder, and carboxymethyl cellulose (Daicel 2200: as a thickener). Daicel Chemical Industries, Ltd.) were mixed so that the weight ratio of the solid content was 100:7.5:2.9:15.3, and water was added to adjust the slurry to an appropriate viscosity. The aluminum foil was coated on one side with a doctor blade. The average basis weight after drying was 1.8 mg/cm ² . This was punched out to a diameter of 16 mm to obtain a positive electrode. An electrode and a battery were produced in the same manner as in Example 1 except for the above. Evaluation was performed in the same manner as in Example 1 except that the reference current value was 0.3 mA.

[Example 3]
Carbon C (manufactured by Toyo Tanso Co., Ltd.) was used as the positive electrode active material, and an electrode and a battery were prepared by the same method as in Comparative Example 1 except for the above. The average basis weight after drying was 1.0 mg/cm ² . Evaluation was performed in the same manner as in Example 1 except that the reference current value was 0.3 mA.

[ Reference Example 4 ]
Carbon D (manufactured by Toyo Tanso Co., Ltd.) was used as the positive electrode active material, and other than that, an electrode and a battery were prepared by the same method as in Example 1 . The average basis weight after drying was 2.5 mg/cm ² . Evaluation was performed in the same manner as in Example 1 except that the reference current value was 0.3 mA.

[Comparative Example 1]
As the positive electrode active material, natural graphite (special CP: manufactured by Nippon Graphite Industry Co., Ltd.) is used, acetylene black (Denka Black powder: Electrochemical Industry) is used as a conduction aid, acrylate latex (TRD202A: JSR) is used as a binder, and a thickening agent is used. Carboxymethyl cellulose (Daicel 2200: Daicel Chemical Industries) as an agent is mixed so that the weight ratio of solids is 100:7.5:3.0:3.8, and water is added to obtain an appropriate viscosity. The adjusted slurry was applied to one surface of an aluminum foil having a thickness of 20 μm using a doctor blade. The average basis weight after drying was 10.5 mg/cm ² . An electrode and a battery were produced in the same manner as in Example 1 except for the above. Evaluation was performed in the same manner as in Example 1 except that the reference current value was 0.075 mA.

[Comparative example 2]
Activated carbon (Belle Fine AP: manufactured by AT Electrode) was used as the positive electrode active material. An electrode and a battery were prepared in the same manner as in Comparative Example 1 except for the above. The average basis weight after drying was 8.9 mg/cm ² . Evaluation was performed in the same manner as in Example 1 except that the reference current value was 2.0 mA.

[Comparative Example 3]
Mesoporous carbon (carbon mesoporous: manufactured by Sigma-Aldrich) is used as the positive electrode active material, acetylene black (Denca black powder: Electrochemical Industry) as a conductive additive, an acrylate latex (TRD202A: JSR) as a binder, and a thickener. As a mixture, carboxymethyl cellulose (Daicel 2200: Daicel Chemical Industries) is mixed so that the weight ratio of solids is 100:7.5:5.8:17.8, and water is added to adjust to an appropriate viscosity. The obtained slurry was applied to one surface of an aluminum foil having a thickness of 20 μm using a doctor blade. The average basis weight after drying was 1.3 mg/cm ² .
An electrode and a battery were prepared in the same manner as in Example 1 except for the above.
Evaluation was performed in the same manner as in Example 1 except that the reference current value was 0.075 mA.
The results are summarized in Table 1.

Table 1 shows, as the charge/discharge test results, the discharge capacity at the fifth time and the discharge capacity at the tenth time at the reference current value in (I) and (II), respectively. The physical property values of the positive electrode active material are also shown. D50 is laser diffraction method, mesopore diameter is calculated by BJH method of gas adsorption curve, and specific surface area is measured value by gas adsorption method. The discharge capacity is described as the specific capacity per weight of the positive electrode active material.

In Example 1, the discharge capacity at the fifth time at the reference current value was a high capacity exceeding 100 mAh/g. The discharge capacity at the 10th time was 63 mAh/g.
In Example 2, the discharge capacity at the 5th time at the reference current value was a high capacity exceeding 100 mAh/g, and the discharge capacity at the 10th time was 44 mAh/g.
In Example 3, the discharge capacity at the 5th time at the reference current value was a high capacity exceeding 100 mAh/g, and the discharge capacity at the 10th time was 92 mAh/g.
In Reference Example 4, the discharge capacity at the 5th time at the reference current value was as high as 72 mAh/g, and the discharge capacity at the 10th time was 60 mAh/g.
On the other hand, Comparative Example 1 (natural graphite) has a discharge capacity of 49 mAh/g at the reference current value, which is lower than that of Examples 1, 2, 3, and Reference Example 4 , and is 49 mAh/g. The capacities were lower than those of Examples 1 and 2 and Reference Example 4 and were 47 mAh/g, which is the same as that of Example 3. Comparative Example 2 (activated carbon) has a high specific surface area, but the discharge capacity at the 5th time at the reference current value is 41 mAh/g, which is lower than those of Examples 1, 2, 3 and Reference Example 4 , and the discharge capacity at the 10th time at the reference current value. Also, it was 40 mAh/g, which was lower than those in Examples 1, 2, 3 and Reference Example 4 . Comparative Example 3 (mesoporous carbon) had a discharge capacity of 25 mAh/g at the reference current value, which was lower than that of Examples 1, 2, 3, and Reference Example 4 , and was 25 mAh/g. It was 25 mAh/g, which was lower than 1, 2, 3 and Reference Example 4 . It is considered that this is because, although it has mesopores, it does not have a three-dimensional network structure and ions do not move smoothly.

Regarding the discharge capacity at the 10th time with respect to the discharge capacity at the 5th time at the reference current value, the capacity change is large in Example 1, the discharge capacity maintenance rate is 52%, the discharge capacity maintenance rate in Example 2 is 76%, and the discharge capacity maintenance rate is 3%. Had a discharge capacity retention rate of 33% and Reference Example 4 had a discharge capacity of 83%, whereas Comparative Examples 1 to 3 had a discharge capacity retention rate of about 100%. The lower the capacity, the higher the discharge capacity retention rate, but the absolute capacities were higher in Examples 1, 2, 3 and Reference Example 4 , and a higher capacity could be obtained.

Further, FIG. 1 shows a plot of the discharge capacities with respect to the number of charge/discharge cycles of Examples 1 to 3 and Reference Example 4 and Comparative Examples 1 to 3 . The initial discharge capacity was 296 mAh/g in Example 1, 191 mAh/g in Example 2, 371 mAh/g in Example 3, and 115 mAh/g in Reference Example 4 , which was a high capacity. On the other hand, the initial discharge capacity of Comparative Example 1 (natural graphite) was 54 mAh/g, the initial discharge capacity of Comparative Example 2 (activated carbon) was 54 mAh/g, and the initial discharge capacity of Comparative Example 3 (mesoporous carbon) was 34 mAh/g. It can be seen that the capacities are lower than those of Examples 1, 2, 3 and Reference Example 4 . In Examples 1 and 3, the initial discharge capacity is high and the capacity decreases as the number of cycles increases, but the capacity is higher than Comparative Examples 1 to 3 even at the 10th cycle. Although the initial discharge capacity of Reference Example 4 is lower than those of Examples 1, 2, and 3, the capacity is stable even when the number of cycles is increased. It is considered that the increase in the mesopore diameter promotes more stable and smooth ion movement.
From this result, it is possible to use a positive electrode active material having a non-crystalline porous carbon having a mesopore having a three-dimensional network structure as the carbon active material, thereby utilizing the anion insertion into the positive electrode to obtain a high energy density It is understood that a water electrolyte storage element can be provided.

Japanese Patent No. 4392169 Japanese Patent No. 4314087 Japanese Patent No. 4569126 WO2008-123606 WO2011-065484

Claims (4)

A positive electrode containing a positive electrode active material capable of inserting or releasing anions,
A negative electrode containing a negative electrode active material,
A non-aqueous solvent, and a non-aqueous electrolytic solution containing an electrolyte salt containing a halogen atom,
A non-aqueous electrolyte storage element having:
The electrolyte salt is a lithium salt,
The negative electrode active material is a lithium metal foil,
The carbon active material used for the positive electrode active material is amorphous porous carbon having mesopores having a three-dimensional network structure and having continuous pore diameters of 2 nm or more and 50 nm or less ,
In the positive electrode, the nonaqueous electrolytic solution storage element is charged by forming a charge layer by the anion and causing a chemical reaction between the anion and the positive electrode active material to charge the nonaqueous electrolytic solution storage element. Nonaqueous electrolytic capacitor element according to claim 1 the value of BET specific surface area of the porous carbon 500~2000m ² / g, the Mi black pore volume is 0.01~1.00mL / g. The lithium salt is LiPF ₆ The non-aqueous electrolyte storage element according to any one of claims 1 to 2. The nonaqueous electrolytic solution electricity storage device according to claim 1, wherein the concentration of the lithium salt is 2 mol/L to 4 mol/L.