JP2020036050A - Nonaqueous lithium-type power storage element - Google Patents

Abstract

To provide a nonaqueous lithium-type power storage element which is low in resistance and has high durability at a high temperature, specifically, has no performance deterioration caused by gas generation due to electrolyte decomposition even if exposed to the high temperature for a long period of time, and which also has high flame-retardant safety.SOLUTION: In a nonaqueous lithium-type power storage element, am electrode laminate including a negative electrode body, a positive electrode body, and a separator, and a nonaqueous electrolyte are housed in an exterior body. The nonaqueous electrolyte contains an organic solvent containing (a) a specific cyclic carbonate compound, (b) a specific chain cyclic carbonate compound, and (c) a specific chain halogenated ether compound, a volume ratio of the (b) component being 20% or more based on the total amount of the organic solvent. The nonaqueous electrolyte contains, as an electrolyte salt, LiFSI and the other electrolyte salt, a used amount of LiFSI being 50 pts.mol or more when the total of LiFSI and the other electrolyte salt is 100 pts.mol.SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous lithium-type energy storage device.

In recent years, from the viewpoint of conservation of the global environment and effective use of energy with the aim of conserving resources, late-night power storage systems, distributed home storage systems based on photovoltaic power generation technology, storage systems for electric vehicles, etc. have attracted attention. I have.
The first requirement in these power storage systems is that the energy density of the power storage element used is high. Lithium-ion batteries are being vigorously developed as a promising candidate for a storage element having a high energy density that can meet such demands.
The second requirement is that the output characteristics be high. For example, in a combination of a high-efficiency engine and a power storage system (for example, a hybrid electric vehicle) or a combination of a fuel cell and a power storage system (for example, a fuel cell electric vehicle), a high-power discharge characteristic of the power storage system is required during acceleration. Have been.

Currently, electric double-layer capacitors, nickel-metal hydride batteries, and the like have been developed as high-power storage elements.
Among the electric double layer capacitors, those using activated carbon for the electrodes have output characteristics of about 0.5 to 1 kW / L. This electric double-layer capacitor has high durability (in particular, cycle characteristics and high-temperature storage characteristics), and has been considered to be an optimal electric storage element in the field where high output is required. However, its practical use is hindered by its low energy density of about 1 to 5 Wh / L and its short output duration.

On the other hand, nickel-metal hydride batteries currently used in hybrid electric vehicles achieve high output equivalent to an electric double layer capacitor and have an energy density of about 160 Wh / L. However, researches for further increasing the energy density and output thereof, further improving the stability at high temperatures, and increasing the durability have been vigorously pursued.
Research is also being conducted on high-output lithium-ion batteries. For example, a lithium ion battery has been developed which can provide a high output exceeding 3 kW / L at a discharge depth of 50% (that is, a value representing what percentage of the discharge capacity of the element has been discharged). However, the energy density is 100 Wh / L or less, and the design is such that the high energy density, which is the greatest feature of the lithium ion battery, is intentionally suppressed. Further, its durability (in particular, cycle characteristics and high-temperature storage characteristics) is inferior to electric double layer capacitors. Therefore, a lithium ion battery can be used only in a range where the depth of discharge is narrower than the range of 0 to 100% in order to have practical durability. Since the capacity that can be actually used is further reduced, research for further improving the durability is being vigorously pursued.
As described above, there is a strong demand for practical use of a storage element having both high output density, high energy density, and durability. However, the above-described existing storage elements have advantages and disadvantages. Therefore, a new power storage device that satisfies these technical requirements has been demanded, and a power storage device called a lithium ion capacitor has been actively developed as a promising candidate in recent years.

A lithium ion capacitor is a type of a storage element using a non-aqueous electrolyte containing an electrolyte containing lithium ions (that is, a non-aqueous lithium-type storage element).
In the positive electrode, similar to electric double layer capacitors, non-Faraday reaction by adsorption and desorption of anions,
The negative electrode is a power storage element that performs charging and discharging by a Faraday reaction due to insertion and extraction of lithium ions, similar to a lithium ion battery.

  As described above, an electric double layer capacitor that performs charging and discharging by a non-Faraday reaction in both the positive electrode and the negative electrode has excellent output characteristics but low energy density. On the other hand, a lithium ion battery, which is a secondary battery that performs charge and discharge by a Faraday reaction in both the positive electrode and the negative electrode, has an excellent energy density, but has poor output characteristics. A lithium ion capacitor is a new power storage element that aims to achieve both excellent output characteristics and high energy density by performing charging and discharging by a non-Faraday reaction on the positive electrode and a Faraday reaction on the negative electrode.

  Uses of the lithium ion capacitor include, for example, railway, construction equipment, and automobile power storage. In these applications, since the operating environment is severe, it is required that the capacitors used do not deteriorate in electrochemical characteristics even when used in a wide temperature range from a high temperature to a low temperature. In particular, at high temperatures, performance degradation caused by gas generation due to decomposition of the electrolytic solution, and at low temperatures, performance degradation caused by a decrease in the conductivity of the electrolytic solution has become a problem. As a countermeasure technique for such a problem, a lithium ion capacitor containing a fluorinated cyclic carbonate in an electrolytic solution has been proposed (see Patent Documents 1 and 2). Further, a lithium ion capacitor containing vinylene carbonate or a derivative thereof in an electrolytic solution has been proposed (see Patent Document 3).

JP 2006-286926 A JP 2013-55285 A JP 2006-286924 A JP 2012-38900 A JP 2014-110371 A

Although the technology of Patent Document 1 can improve the characteristics at low temperatures, the effect of improving the durability at high temperatures has not been confirmed. Patent Document 2 discloses a technique for improving initial characteristics by suppressing gas generated during a process of manufacturing a capacitor. No effect has been confirmed on improvement in durability of a completed capacitor at a high temperature. Patent Document 3 provides a capacitor having a high capacity retention rate during continuous charging of a power storage element at a high temperature. However, this patent document does not show any result regarding the change in characteristics after the high-temperature test. Patent Document 4, similarly to Patent Document 2, relates to a technique for improving initial characteristics by suppressing gas generated in a process of manufacturing a capacitor, and has been confirmed to be effective in improving durability of a completed capacitor at high temperatures. Not. Further, Patent Document 5 discloses a technique for maintaining initial characteristics and cycle characteristics by adding a flame retardant additive to an electrolyte solution. However, in this technique, the flame-retardant effect is unknown and safety has not been confirmed, and improvement in durability at high temperatures has not been verified.
As described above, in the conventional lithium ion capacitor, only the initial characteristics are evaluated by focusing on the initial characteristics. No safe technology has been found in which generation and reduction in performance due to the generation are suppressed and high flame retardancy is obtained.
Therefore, the problem to be solved by the present invention is low resistance, high durability at high temperatures, specifically, no gas generation due to electrolyte decomposition even when exposed to high temperatures for a long time, and performance degradation due to gas generation. It is an object of the present invention to provide a non-aqueous lithium-type energy storage device that has a high level of flame-retardant safety and establishes a technology that does not have such a feature.

The present inventors have intensively studied and conducted experiments to solve the above problems. As a result, the electrolyte of the lithium ion capacitor contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ) as an electrolyte, and at least one specific compound, has low resistance and high temperature. It has been found that a lithium ion capacitor having a high durability and a high level of safety due to a flame-retardant effect is provided, and the present invention has been completed.
That is, the present invention is as follows.

[1] A non-aqueous lithium-type energy storage device including an electrode laminate including a negative electrode body, a positive electrode body, and a separator, and a non-aqueous electrolyte solution housed in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent, and the nonaqueous electrolytic solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ). A non-aqueous lithium-type energy storage device, comprising:

[2] The method according to [1], wherein the concentration of LiN (SO ₂ F) _{2 in} the non-aqueous electrolyte is 0.3 mol / L or more and 1.5 mol / L or less based on the total amount of the non-aqueous electrolyte. Non-aqueous lithium storage element.
[3] The non-aqueous lithium-type energy storage device according to [1] or [2], wherein the non-aqueous electrolyte contains at least one of LiPF ₆ and LiBF ₄ .

[4] the in the non-aqueous electrolyte solution (c) _{compounds, C 2 F 5 OCH 3,} C 3 F 7 OCH 3, C 4 F 9 OCH 3, C 6 F 13 OCH 3, C 2 F 5 OC 2 H _{5, C 3 F 7 OC 2} H 5, C 4 F 9 OC 2 H 5, C 2 F 5 CF (OCH 3) C 3 F 7, CF 3 CH 2 OCF 2 CF 2 H, CHF 2 CF 2 OCH 2 _{CF 3, CHF 2 CF 2 CH} 2 OCF 2 CF 2 H, from _{CF 3 CF 2 CH 2 OCF 2} CHF 2, CF 3 CH 2 OCF 2 CHFCF 3, and _{C 3 HF 6 CH (CH 3} ) OC 3 HF 6 Any of [1] to [3], comprising at least one compound selected from the group consisting of: and wherein the volume ratio of these compounds is 0.1% to 50% based on the total amount of the organic solvent. Or non- Water-based lithium storage element.
[5] The non-aqueous electrolyte further contains at least one compound selected from the group consisting of sultone compounds, cyclic phosphazenes, fluorinated cyclic carbonates, cyclic carbonates, cyclic carboxylic esters, and cyclic acid anhydrides. The non-aqueous lithium-type energy storage device according to any one of [1] to [4].

｛式中、Ｒ^１〜Ｒ^６は、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、及び炭素数１〜１２のハロゲン化アルキル基からなる群より選ばれるいずれかを表し、互いに同一であっても異なっていてもよく；そして
ｎは０〜３の整数である。｝、下記一般式（２）：

｛式中、Ｒ^１〜Ｒ^４は、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、及び炭素数１〜１２のハロゲン化アルキル基からなる群より選ばれるいずれかを表し、互いに同一であっても異なっていてもよく；そして
ｎは０〜３の整数である。｝、及び下記一般式（３）：

｛式中、Ｒ^１〜Ｒ^６は、水素原子、ハロゲン原子、炭素数１〜６のアルキル基、又は炭素数１〜６のハロゲン化アルキル基であり、互いに同一であっても異なっていてもよい。｝のそれぞれで表される化合物から選択される少なくとも１種のスルトン化合物を、非水系電解液の総量を基準として、０．１質量％〜２０質量％含有する、[１]〜[４]のいずれか一項に記載の非水系リチウム型蓄電素子。 [6] The non-aqueous electrolyte solution,
The following general formula (1):

In the formula, R ^{1 to} R ⁶ represent any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms, and are the same as each other. And n is an integer from 0 to 3. ｝, The following general formula (2):

In the formula, R ^{1 to} R ⁴ represent any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms, and are the same as each other. And n is an integer from 0 to 3. ｝, And the following general formula (3):

In the formula, R ^{1 to} R ⁶ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogenated alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other. Good. [1] to [4], containing at least one sultone compound selected from the compounds represented by｝ in an amount of 0.1% by mass to 20% by mass based on the total amount of the non-aqueous electrolyte. The non-aqueous lithium-type energy storage device according to any one of the preceding claims.

[7] The negative electrode active material is a composite porous material in which the surface of activated carbon is coated with a carbon material, and
The amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method is Vm1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 ° calculated by the MP method is Vm2 (cc / g). ), Satisfying 0.010 ≦ Vm1 ≦ 0.250, 0.001 ≦ Vm2 ≦ 0.200, and 1.5 ≦ Vm1 / Vm2 ≦ 20.0,
The non-aqueous lithium-type energy storage device according to any one of [1] to [6].
[8] The negative electrode active material is a composite porous material in which the surface of activated carbon is coated with a carbon material, and
Lithium ion of 1,050 mAh / g or more and 2,050 mAh / g or less per unit mass of the composite porous material is pre-doped;
The mass ratio of the carbon material to the activated carbon is 10% or more and 60% or less, and the thickness of the negative electrode active material layer is 20 μm or more and 45 μm or less per side.
The non-aqueous lithium-type energy storage device according to any one of [1] to [6].

[9] The negative electrode active material has the following (i) to (iii):
(I) the negative electrode active material is a composite carbon material containing carbon black and a carbon material,
(Ii) the negative electrode is doped with lithium ions of 1,050 mAh / g or more and 2,500 mAh / g or less per unit mass of the negative electrode active material;
(Iii) the thickness of the negative electrode active material layer is from 10 μm to 60 μm per side,
The nonaqueous lithium-type energy storage device according to any one of [1] to [6], which satisfies all of the following.

[10] The positive electrode active material is:
The amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 ° calculated by the MP method is V2 (cc / g). ), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and
Activated carbon having a specific surface area measured by the BET method of not less than 1,500 m ² / g and not more than 3,000 m ² / g.
The non-aqueous lithium-type energy storage device according to any one of [1] to [9].
[11] The positive electrode active material,
A mesopore volume V1 (cc / g) derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method satisfies 0.8 <V1 ≦ 2.5,
The micropore volume V2 (cc / g) derived from pores having a diameter of less than 20 ° calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and
Activated carbon having a specific surface area measured by a BET method of not less than 3,000 m ² / g and not more than 4,000 m ² / g.
The non-aqueous lithium-type energy storage device according to any one of [1] to [9].

[12] A non-aqueous lithium-type power storage element in which an electrode laminate including a negative electrode body, a positive electrode body, and a separator, and a non-aqueous electrolyte solution are housed in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent;
The non-aqueous electrolyte solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ), and the non-aqueous lithium-type storage element is stored for two months at a cell voltage of 4 V and an environmental temperature of 60 ° C. The internal resistance at 25 ° C. is Rb (Ω), the internal resistance at 25 ° C. before storage is Ra (Ω), the internal resistance at −30 ° C. before storage is Rc (Ω), and the capacitance at 25 ° C. before storage is When F (F), the following (a) to (c):
(A) the product Ra · F of Ra and F is 1.9 or less;
(B) Rb / Ra is 1.8 or less; and (c) The amount of gas generated when stored for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C. is 10 × 10 ⁻³ cc / F at 25 ° C. Is the following,
A non-aqueous lithium-type storage element characterized by satisfying all of the above at the same time.

The non-aqueous lithium-type energy storage device according to the present invention has excellent electrochemical characteristics, durability, and high flame-retardant safety.
The non-aqueous lithium-type energy storage device is suitable as a lithium-ion capacitor in the field of a hybrid drive system in which an internal combustion engine, a fuel cell, or a motor in an automobile is combined with an energy storage device; It is.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.
[Storage element]
An embodiment of the present invention is a non-aqueous lithium-type power storage element. Such a storage element,
An electrode laminate including a negative electrode body, a positive electrode body, and a separator, and a nonaqueous electrolytic solution are housed in a package.
The negative electrode body includes a negative electrode current collector and a negative electrode active material layer provided on one surface or both surfaces of the negative electrode current collector. The negative electrode active material layer contains a negative electrode active material containing a carbon material capable of inserting and extracting lithium ions.
The positive electrode body includes a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector. The positive electrode active material layer contains a positive electrode active material containing activated carbon.

The non-aqueous lithium-type energy storage device according to one embodiment of the present invention has an internal resistance at 25 ° C. Rb (Ω) after storage for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C., and an internal resistance at 25 ° C. before storage. Is Ra (Ω), and the capacitance at 25 ° C. before storage is F (F), and the following (a) to (c):
(A) the product Ra · F of Ra and F is 1.9 or less;
(B) Rb / Ra is 1.8 or less; and (c) The amount of gas generated when stored for 2 months at a cell voltage of 4 V and an ambient temperature of 60 ° C. is 13 × 10 ⁻³ cc / F at 25 ° C. Is the following,
Are preferably satisfied at the same time.

  Here, the capacitance F (F) refers to a constant current constant voltage charge in which a constant voltage charge time of 1 hour is secured at a current value of 1.5 C to 3.8 V, and then to 2.2 V. A value calculated by F = Q / (3.8-2.2) from the capacity Q when a constant current discharge is performed at a current value of 5C. The internal resistances Ra (Ω) and Rb (Ω) are values obtained by the following methods, respectively. First, at an environmental temperature of 25 ° C., constant current charging is performed at a current value of 1.5 C until the voltage reaches 3.8 V, and then constant current constant voltage charging of applying a constant voltage of 3.8 V is performed for a total of 2 hours. Then, a constant current discharge is performed to 2.2 V at a current value of 50 C to obtain a discharge curve (time-voltage). In this discharge curve, when the voltage at the discharge time = 0 second obtained by extrapolating by linear approximation from the voltage values at the discharge time of 2 seconds and 4 seconds is E0, the drop voltage (ΔE) = 3. 8-E0 and R = ΔE / (50C (current value)).

  Further, “storage for two months at a cell voltage of 4.0 V” means that storage is performed for two months while the cell voltage is substantially maintained at 4.0 V. Specifically, by applying a constant voltage of 4.0 V at a current value of 2.0 C with a constant current constant voltage charge of 2 hours each time before storage and every week after the start of storage, Maintain the voltage at 4.0V.

Ra · F is preferably 1.9 or less from the viewpoint that sufficient charge capacity and discharge capacity can be exhibited for a large current, more preferably 1.8 or less, and still more preferably 1 or less. .6 or less.
Further, Rb / Ra is preferably 1.8 or less from the viewpoint that when exposed to a high temperature environment for a long time, sufficient charge capacity and discharge capacity can be exhibited for a large current. It is more preferably 1.6 or less, and still more preferably 1.4 or less.
Further, the amount of gas generated when stored for 2 months at a cell voltage of 4.0 V and an environmental temperature of 60 ° C. is 10% as a value measured at 25 ° C. from the viewpoint that the characteristics of the element are not deteriorated by the generated gas. It is preferably at most 10 × 10 ⁻³ cc / F, more preferably at most 8 × 10 ⁻³ cc / F, even more preferably at most 5.0 × 10 ⁻³ cc / F.

  An energy storage device provided by an embodiment of the present invention exhibits a small Ra · F, Rb / Ra, and a generated gas amount as described above, and realizes a high level of safety by a flame-retardant effect. Exhibit excellent device characteristics that cannot be provided by As an example of a means for achieving such small Ra · F, Rb / Ra, and the amount of generated gas, and for realizing a high degree of safety by a flame-retardant effect, for example, a specific non-aqueous system as described below Application of electrolyte composition is mentioned.

[Electrolyte]
The electrolyte in the embodiment of the present invention is a non-aqueous electrolyte. That is, the non-aqueous electrolyte comprises (a) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent, and the nonaqueous electrolytic solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ). .

The concentration of LiN (SO ₂ F) ₂ in the non-aqueous electrolyte of this embodiment is preferably 0.3 mol / L or more and 1.5 mol / L or less, more preferably 0.6 mol / L or more and 1.2 mol. / L or less. When the concentration of LiN (SO ₂ F) ₂ is 0.3 mol / L or more, the ionic conductivity of the electrolytic solution can be increased, and gas suppression due to decomposition of the electrolytic solution can be reduced. On the other hand, if this value is 1.5 mol / L or less, no precipitation of the electrolyte salt occurs during charging and discharging, and the viscosity of the electrolyte does not increase even after a long period of time.

The non-aqueous electrolyte solution may contain only the above-mentioned LiN (SO ₂ F) ₂ as an electrolyte salt, or may contain other electrolyte salts.
As the other electrolyte salt contained in the non-aqueous electrolyte, a fluorine-containing lithium salt having a solubility of 0.5 mol / L or more in the non-aqueous electrolyte can be used. Suitable lithium salts include, for example, LiPF ₆ , LiBF ₄ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₅ ), and LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₄ H), and their mixed salts. As the other electrolyte salt, from the viewpoint of developing high conductivity, it is preferable to use one or more selected from LiPF ₆ and LiBF _4, and it is particularly preferable to use LiPF ₆ .

When another electrolyte salt is used in the non-aqueous electrolyte of the present embodiment, the amount of the electrolyte salt used is 0 when the total amount of LiN (SO ₂ F) ₂ and the other electrolyte salt is 100 mol parts. The molar amount is preferably from mol to 80 mol, more preferably from 10 to 65 mol, and still more preferably from 15 to 50 mol. If the amount of the other electrolyte salt used is 50 mol parts or less, it is possible to suppress the decomposition of the electrolytic solution at a high temperature, and suppress the gas generation and the increase in resistance. On the other hand, when this value is 15 mol parts or more, it is possible to suppress corrosion of the positive electrode current collector, which is preferable.

As for the content of the component (a), the volume ratio is preferably 10% to 50% based on the total amount of the organic solvent. By setting the content of the component (a) in this range, it is possible to maintain the electrolyte at low viscosity while maintaining high conductivity. The volume ratio of the component (a) based on the total amount of the organic solvent is more preferably 15% to 45%, and still more preferably 20% to 40%. When the content of the component (a) is represented by a mass ratio based on the total amount of the organic solvent, the content is preferably 10% to 60%, more preferably 15% to 55%, and still more preferably 20% to 55%. 50%.
Regarding the content of the component (b), its volume ratio is 20% or more based on the total amount of the organic solvent. When the volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent, it is possible to keep the viscosity of the obtained electrolyte solution low while keeping the conductivity high. On the other hand, if the content of the component (b) is excessively high, it may be disadvantageous in that the durability at high temperatures is lost. Therefore, the volume ratio of the component (b) based on the total amount of the organic solvent is preferably 30% to 90%, and more preferably 35% to 80%. When the content of the component (b) is represented by a mass ratio based on the total amount of the organic solvent, the content is preferably 20% to 85%, more preferably 25% to 80%, and still more preferably 30% to 80%. 75%.

In the non-aqueous electrolyte according to the present embodiment, examples of the compound represented by the general formula (c) (component (c)) include CF ₃ OCH _3, CF ₃ OCF _3, CF ₃ CH ₂ OCH ₃ , and C _{2 F 5 OCH 3, C 2} F 5 OCF 3, C 2 F 5 OC 2 H 5, C 2 F 5 OC 2 F 5, CF 3 CH 2 OC 2 H 5, C 3 F 7 OCH 3, C 3 F ₇ OC ₂ H ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , C ₄ F ₉ OC ₃ H ₇ , C ₄ F ₉ OC ₄ H ₉ , C ₅ F ₁₁ OCH ₃ , C ₅ F _{11 OC 2 H 5, C 5} F 11 OC 3 H 7, C 5 F 11 OC 4 H 9, C 5 F 11 OC 5 H 11, C 6 F 13 OCH 3, C 6 F 13 OC 2 H 5, C _{6 F 13 OC 3 H 7,} C 6 F 13 O _{4 H 9, C 6 F 13} OC 5 H 11, C 6 F 13 OC 6 H 13, C 2 F 5 CF (OCH 3) C 3 F 7, C 2 F 5 OCF 2 CF 2 H, CHF 2 CF 2 _{OCH 2 CF 3, CHF 2 CF} 2 CH 2 OCF 2 CF 2 H, C 2 F 5 CH 2 OCF 2 CHF 2, CF 3 CH 2 OCF 2 CHFCF 3, C 3 HF 6 CH (CH 3) OC 3 HF 6 And the like, and it is preferable to use at least one selected from the group consisting of these.

  The content of the component (c) is preferably 0.1% to 50%, more preferably 1% to 40%, as a volume ratio based on the total amount of the organic solvent. When the content of the component (c) is 1% or more, it can be expected that the obtained electrolytic solution has a high level of flame retardant safety. On the other hand, when the content of the component (c) is 40% or less, the viscosity of the obtained electrolytic solution can be kept low. As a result, the ionic conductivity of the electrolytic solution can be maintained at a high level, so that high input / output characteristics can be exhibited. When the content of the component (c) is expressed as a mass ratio based on the total amount of the organic solvent, it is preferably 0.1% to 55%, more preferably 1% to 45%.

  The non-aqueous electrolyte in the present embodiment further includes, as an additive, at least one selected from the group consisting of a sultone compound, a cyclic phosphazene, a fluorinated cyclic carbonate, a cyclic carbonate, a cyclic carboxylate, and a cyclic acid anhydride. It is preferable to contain the compound of formula (I).

  As the sultone compound, the following general formula (1):

In the formula, R ^{1 to} R ⁶ represent any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms, and are the same as each other. And n is an integer from 0 to 3. ｝, The following general formula (2):

In the formula, R ^{1 to} R ⁴ represent any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms, and are the same as each other. And n is an integer from 0 to 3. ｝, And the following general formula (3):

In the formula, R ^{1 to} R ⁶ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogenated alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other. Good. It is preferable to use at least one kind of sultone compound selected from the compounds represented by each of｝.

Examples of the halogen atom represented by R _{1 to} R _{6 in} all of the formulas (1) to (3) include a fluorine atom, a chlorine atom, and an iodine atom;
Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group;
Examples of the halogenated alkyl group include a fluoroalkyl group and a perfluoroalkyl group.
In the above formulas (1) and (2), n is preferably independently an integer of 0 to 2, more preferably 0 or 1.

  As the sultone compound contained in the non-aqueous electrolyte in the present embodiment, 1,3-propane sultone is used from the viewpoint that the adverse effect on the resistance is small and that the decomposition of the non-aqueous electrolyte at a high temperature is suppressed to suppress gas generation. 2,4-butane sultone, 1,4-butane sultone, 1,3-butane sultone or 2,4-pentane sultone, 1,3-propene sultone or 1,4-butene sultone, 1,5,2,4-dioxadi Thiepane 2,2,4,4-tetraoxide, methylenebis (benzenesulfonic acid), methylenebis (phenylmethanesulfonic acid), methylenebis (ethanesulfonic acid), methylenebis (2,4,6, trimethylbenzenesulfonic acid), and At least one member selected from the group consisting of methylenebis (2-trifluoromethylbenzenesulfonic acid) Sultone compounds are preferred.

The content of the sultone compound in the non-aqueous electrolyte is preferably 0.1% by mass to 20% by mass based on the total amount of the non-aqueous electrolyte. When this value is 0.1% by mass or more, decomposition of the electrolytic solution at a high temperature can be suppressed, and gas generation can be suppressed. On the other hand, when this value is 20% by mass or less, a decrease in the ionic conductivity of the electrolytic solution can be suppressed, and high input / output characteristics can be maintained. For the above reasons, the content of the sultone compound is preferably from 5% by mass to 15% by mass, and more preferably from 7% by mass to 12% by mass.
These sultone compounds may be used alone or in combination of two or more.

  Examples of the cyclic phosphazene include ethoxypentafluorocyclotriphosphazene, diethoxytetrafluorocyclotriphosphazene, and phenoxypentafluorocyclotriphosphazene, and one or more selected from these are preferable.

The content of the cyclic phosphazene in the non-aqueous electrolyte is preferably 0.5% by mass to 20% by mass based on the total amount of the non-aqueous electrolyte. When this value is 0.5% by weight or more, decomposition of the electrolytic solution at a high temperature can be suppressed, and gas generation can be suppressed. On the other hand, when this value is 20% by mass or less, a decrease in the ionic conductivity of the electrolytic solution can be suppressed, and high input / output characteristics can be maintained. For the above reasons, the content of the cyclic phosphazene is preferably from 2% by mass to 15% by mass, and more preferably from 4% by mass to 12% by mass.
In addition, these cyclic phosphazenes may be used alone or in combination of two or more.

The fluorinated cyclic carbonate is preferably selected from fluoroethylene carbonate (FEC) and difluoroethylene carbonate (dFEC) from the viewpoint of compatibility with other non-aqueous solvents.
The content of the cyclic carbonate containing a fluorine atom is preferably from 0.5% by mass to 10% by mass, more preferably from 1% by mass to 5% by mass, based on the total amount of the non-aqueous electrolyte. When the content of the cyclic carbonate containing a fluorine atom is 0.5% by mass or more, a high-quality film can be formed on the negative electrode, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, A power storage element with high durability can be obtained. On the other hand, when the content of the cyclic carbonate containing a fluorine atom is 10% by mass or less, the solubility of the electrolyte salt can be kept good, and the ionic conductivity of the non-aqueous electrolyte can be kept high. It is possible to exhibit advanced input / output characteristics.
In addition, the above-mentioned cyclic carbonate containing a fluorine atom may be used alone or in combination of two or more.

As the cyclic carbonate, vinylene carbonate is preferred.
The content of the cyclic carbonate is preferably from 0.5% by mass to 10% by mass, more preferably from 1% by mass to 5% by mass, based on the total amount of the non-aqueous electrolyte. When the content of the cyclic carbonate is 0.5% by mass or more, a high-quality coating on the negative electrode can be formed, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, the durability at high temperatures can be improved. A high power storage element can be obtained. On the other hand, when the content of the cyclic carbonate is 10% by mass or less, the solubility of the electrolyte salt can be kept good, and the ionic conductivity of the non-aqueous electrolyte can be kept high. Can be expressed.

  Examples of the cyclic carboxylic acid ester include gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone, and the like, and it is preferable to use one or more selected from these. Among them, gamma-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics derived from the improvement of the degree of dissociation of lithium ions.

The content of the cyclic carboxylate is preferably from 0.5% by mass to 15% by mass, more preferably from 1% by mass to 5% by mass, based on the total amount of the non-aqueous electrolyte. When the content of the cyclic acid anhydride is 0.5% by mass or more, a good-quality film on the negative electrode can be formed, and by suppressing reductive decomposition of the electrolytic solution on the negative electrode, durability at high temperatures can be improved. , A power storage element having a high value can be obtained. On the other hand, when the content of the cyclic carboxylic acid ester is 5% by mass or less, the solubility of the electrolyte salt can be kept good, and the ionic conductivity of the non-aqueous electrolyte can be kept high. It becomes possible to express characteristics.
The above-mentioned cyclic carboxylic esters may be used alone or in combination of two or more.

  The cyclic acid anhydride is preferably at least one selected from succinic anhydride, maleic anhydride, citraconic anhydride, and itaconic anhydride. Among them, it is preferable to select from succinic anhydride and maleic anhydride in view of the fact that the production cost of the electrolytic solution is reduced due to industrial availability, and that it is easily dissolved in a non-aqueous electrolytic solution.

The content of the cyclic acid anhydride is preferably from 0.5% by mass to 15% by mass, more preferably from 1% by mass to 10% by mass, based on the total amount of the non-aqueous electrolyte. When the content of the cyclic acid anhydride is 0.5% by mass or more, a good-quality film can be formed on the negative electrode, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, high-temperature durability can be improved. A high power storage element can be obtained. On the other hand, if the content of the cyclic acid anhydride is 10% by mass or less, the solubility of the electrolyte salt can be kept good, and the ionic conductivity of the non-aqueous electrolyte can be kept high. It becomes possible to express characteristics.
The above-mentioned cyclic acid anhydrides may be used alone or in combination of two or more.

As the additive in the non-aqueous electrolyte of the present embodiment,
Use only sultone compounds; or
A sultone compound;
Cyclic phosphazene, fluorine-containing cyclic carbonate, cyclic carbonate, cyclic carboxylate, and at least one compound selected from the group consisting of cyclic acid anhydrides;
Is preferably used in combination. In the latter case, it is more preferable to use a sultone compound and a cyclic phosphazene in combination.

[Positive electrode body and negative electrode body]
The positive electrode body in the non-aqueous lithium-type energy storage device of the present embodiment,
A positive electrode current collector,
A positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector. The positive electrode active material layer contains a positive electrode active material containing activated carbon.
The negative electrode body is
A negative electrode current collector,
A negative electrode active material layer provided on one surface or both surfaces of the negative electrode current collector. The negative electrode active material layer contains a negative electrode active material containing a carbon material capable of inserting and extracting lithium ions.
In the positive and negative electrode bodies of this embodiment, a common configuration can be applied to components other than the positive electrode active material and the negative electrode active material. Hereinafter, after the positive electrode active material and the negative electrode active material are described in order, common elements are collectively described.

[Positive electrode active material]
The positive electrode active material contains activated carbon. As the positive electrode active material, only activated carbon may be used, or in addition to activated carbon, other materials as described later may be used in combination. The content of the activated carbon based on the total amount of the positive electrode active material is preferably 50% by mass or more, and more preferably 70% by mass or more. The content may be 100% by mass, but from the viewpoint of obtaining the effect of using other materials in combination, for example, the content is preferably 90% by mass or less, and may be 80% by mass or less.
There are no particular restrictions on the type of activated carbon and its raw material in the positive electrode active material, but it is preferable to optimally control the pores of activated carbon in order to achieve high input / output characteristics and high energy density. Specifically, the amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 ° is calculated by the MP method. When V2 (cc / g),
(1) For high input / output characteristics, 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the specific surface area measured by the BET method is 1,500 m ^2. / G or more and 3,000 m ² / g or less (hereinafter also referred to as “activated carbon 1”), or
(2) In order to obtain a high energy density, 0.8 <V1 ≦ 2.5 and 0.8 <V2 ≦ 3.0 are satisfied, and the specific surface area measured by the BET method is 3,000 m ^2. / G or more and 4,000 m ² / g or less (hereinafter, also referred to as “activated carbon 2”) is preferred.

Hereinafter, (1) the activated carbon 1 and (2) the activated carbon 2 will be described individually and sequentially.
[Activated carbon 1]
The mesopore amount V1 of the activated carbon 1 is preferably a value larger than 0.3 cc / g from the viewpoint of improving the input / output characteristics when the positive electrode material is incorporated in the electric storage device. On the other hand, the concentration is preferably 0.8 cc / g or less from the viewpoint of suppressing a decrease in the bulk density of the positive electrode. V1 is more preferably 0.35 cc / g or more and 0.7 cc / g or less, and still more preferably 0.4 cc / g or more and 0.6 cc / g or less.
The micropore volume V2 of the activated carbon 1 is preferably 0.5 cc / g or more in order to increase the specific surface area of the activated carbon and increase the capacity. On the other hand, it is preferably 1.0 cc / g or less from the viewpoint of suppressing the bulk of activated carbon, increasing the density as an electrode, and increasing the capacity per unit volume. V2 is more preferably 0.6 cc / g or more and 1.0 cc / g or less, and still more preferably 0.8 cc / g or more and 1.0 cc / g or less.

The ratio (V1 / V2) of the mesopore volume V1 to the micropore volume V2 is preferably in the range of 0.3 ≦ V1 / V2 ≦ 0.9. That is, V1 / V2 is preferably 0.3 or more from the viewpoint of increasing the ratio of the mesopore amount to the micropore amount to such an extent that a decrease in output characteristics can be suppressed while obtaining a high capacity. On the other hand, V1 / V2 is preferably 0.9 or less from the viewpoint of increasing the ratio of the amount of micropores to the amount of mesopores to such an extent that a reduction in capacity can be suppressed while obtaining high output characteristics. A more preferable range of V1 / V2 is 0.4 ≦ V1 / V2 ≦ 0.7, and a still more preferable range of V1 / V2 is 0.55 ≦ V1 / V2 ≦ 0.7.
In the present invention, the micropore amount and the mesopore amount are values obtained by the following method. That is, the sample is vacuum-dried at 500 ° C. all day and night, and the adsorption / desorption isotherm is measured using nitrogen as an adsorbate. Using the isotherm on the desorption side at this time, the amount of micropores is calculated by the MP method, and the amount of mesopores is calculated by the BJH method.

The MP method is based on the “t-plot method” (BC Lippens, JH de Boer, J. Catalysis, 4319 (1965)) and uses the micropore volume, micropore area, and micropore. Means a method for obtaining the distribution of This is a method devised by Mikhal, Brunauer, and Bodor (RS Mikhal, S. Brunauer, EE Bodor, J. Colloid Interface Sci., 26, 45 (1968)).
The BJH method is a calculation method generally used for analysis of mesopores, and has been proposed by Barrett, Joyner, Hallenda et al. (EP Barrett, LGJoyner and P. Hallenda, J. Am. Chem. Soc., 73, 373 (1951)).

The average pore diameter of the activated carbon 1 is preferably 17 ° or more, more preferably 18 ° or more, and most preferably 20 ° or more from the viewpoint of maximizing the output of the obtained storage element. Further, from the viewpoint of maximizing the capacity of the obtained electric storage element, the angle is preferably 25 ° or less. The average pore diameter described in the present specification means the total pore volume per sample mass obtained by measuring each equilibrium adsorption amount of nitrogen gas at each relative pressure under the temperature of liquid nitrogen. Divided by.
The BET specific surface area of the activated carbon 1 is preferably from 1,500 m ² / g to 3,000 m ² / g, more preferably from 1,500 m ² / g to 2,500 m ² / g. When the BET specific surface area is 1,500 m ² / g or more, a good energy density is easily obtained. On the other hand, when the BET specific surface area is 3,000 m ² / g or less, in order to maintain the strength of the electrode, Since it is not necessary to add a large amount of the binder, the performance per electrode volume tends to be high.

The activated carbon 1 having the above characteristics can be obtained, for example, by using the raw materials and the processing method described below.
In the embodiment of the present invention, the carbon source used as a raw material of the activated carbon 1 is not particularly limited. For example, wood, wood flour, coconut shell, by-products during pulp production, bagasse, molasses and other plant-based materials Raw materials; peat, lignite, lignite, bituminous coal, anthracite, petroleum distillation residue components, petroleum pitch, coke, coal tar and other fossil-based raw materials; phenolic resins, vinyl chloride resins, vinyl acetate resins, melamine resins, urea resins, resorcinol resins, Various synthetic resins such as celluloid, epoxy resin, polyurethane resin, polyester resin, and polyamide resin; synthetic rubber such as polybutylene, polybutadiene, and polychloroprene; other synthetic wood, synthetic pulp, and their carbides. Among these raw materials, from the viewpoints of mass production and cost, plant-based raw materials such as coconut shells and wood flour, and their carbides are preferable, and coconut shell carbides are particularly preferable.

Known methods such as a fixed bed method, a moving bed method, a fluidized bed method, a slurry method, a rotary kiln method and the like can be adopted as a method of carbonizing and activating the above raw materials into the activated carbon 1.
As a method for carbonizing these raw materials, for example, nitrogen, carbon dioxide, helium, argon, xenon, neon, carbon monoxide, an inert gas such as combustion exhaust gas, or another gas containing these inert gases as a main component And a method of baking at about 400 to 700 ° C. (preferably 450 to 600 ° C.) for about 30 minutes to 10 hours.

As a method for activating the carbide obtained by the above-described carbonization method, for example, a gas activation method in which firing is performed using an activation gas such as steam, carbon dioxide, or oxygen is preferably used. Among them, a method using steam or carbon dioxide as the activation gas is preferable.
In this activation method, the carbide is supplied for 3 to 12 hours (preferably 5 to 11 kg) while supplying the activation gas at a rate of 0.5 to 3.0 kg / h (preferably 0.7 to 2.0 kg / h). It is preferable to activate by raising the temperature to 800 to 1,000 ° C. over a period of time, more preferably 6 to 10 hours.
Further, prior to the activation treatment of the carbide, the carbide may be primarily activated in advance. In the primary activation, the carbon material can be gas-activated by firing at a temperature of less than 900 ° C. using an activation gas such as steam, carbon dioxide, or oxygen.
By appropriately combining the calcination temperature and calcination time in the carbonization method and the activation gas supply amount, the heating rate, and the maximum activation temperature in the activation method, the activated carbon 1 having the above characteristics, which can be used in the present embodiment, Can be manufactured.
The average particle size of the activated carbon 1 is preferably 1 to 20 μm. Throughout this specification, “average particle size” refers to the point at which the cumulative curve is 50% when the cumulative curve is determined with the total volume as 100% when the particle size distribution is measured using a particle size distribution measuring device. It refers to the particle size (ie, 50% size (Median size)). This average particle size can be measured with a commercially available laser diffraction type particle size distribution analyzer.

  When the average particle size is 1 μm or more, the capacity per electrode volume tends to increase because the density of the active material layer is high. In addition, a small average particle size may lead to a defect that durability is low, but if the average particle size is 1 μm or more, such a defect is unlikely to occur. On the other hand, when the average particle size is 20 μm or less, there is a tendency that it is easy to adapt to high-speed charge and discharge. The average particle size is more preferably 2 to 15 μm, and still more preferably 3 to 10 μm.

[Activated carbon 2]
It is preferable that the mesopore amount V1 of the activated carbon 2 is larger than 0.8 cc / g from the viewpoint of increasing the output characteristics when the positive electrode material is incorporated in the electric storage device. In addition, from the viewpoint of suppressing a decrease in the capacity of the power storage element, it is preferably 2.5 cc / g or less. V1 is more preferably 1.00 cc / g or more and 2.0 cc / g or less, further preferably 1.2 cc / g or more and 1.8 cc / g or less.

On the other hand, the micropore volume V2 of the activated carbon 2 is preferably larger than 0.8 cc / g in order to increase the specific surface area of the activated carbon and increase the capacity. Further, from the viewpoint of increasing the density of activated carbon as an electrode and increasing the capacity per unit volume, it is preferably 3.0 cc / g or less. V2 is more preferably more than 1.0 cc / g and not more than 2.5 cc / g, and further preferably not less than 1.5 cc / g and not more than 2.5 cc / g.
The measurement method of the micropore amount and the mesopore amount in the activated carbon 2 can be based on the method described above for the activated carbon 1.

The activated carbon 2 having the mesopore volume V1 and the micropore volume V2 described above has a higher BET specific surface area than activated carbon used for a conventional electric double layer capacitor or lithium ion capacitor. The specific value of the BET specific surface area of the activated carbon 2 is preferably from 3,000 m ² / g to 4,000 m ² / g, and is preferably from 3,200 m ² / g to 3,800 m ² / g. Is more preferable. When the BET specific surface area is 3,000 m ² / g or more, good energy density is easily obtained. On the other hand, when the BET specific surface area is 4,000 m ² / g or less, it is not necessary to add a large amount of binder in order to maintain the strength of the electrode, so that the performance per electrode volume tends to increase.
The activated carbon 2 having the above characteristics can be obtained, for example, by using the raw materials and the processing method described below.
The carbon source used as a raw material of the activated carbon 2 is not particularly limited as long as it is a carbon source usually used as a raw material of the activated carbon. For example, plant-based materials such as wood, wood flour, and coconut shells; fossil-based materials such as petroleum pitch and coke; various types such as phenolic resins, furan resins, vinyl chloride resins, vinyl acetate resins, melamine resins, urea resins, and resorcinol resins Synthetic resins and the like can be mentioned. Among these raw materials, phenol resin and furan resin are suitable for producing activated carbon 2 having a high specific surface area, and are particularly preferable.

Examples of a method of carbonizing these raw materials or a heating method during the activation treatment include known methods such as a fixed bed method, a moving bed method, a fluidized bed method, a slurry method, and a rotary kiln method. The atmosphere at the time of heating is an inert gas such as nitrogen, carbon dioxide, helium, or argon, or a mixed gas of these inert gases as a main component and other gases. A method of firing at a carbonization temperature of about 400 to 700 ° C. for about 0.5 to 10 hours is generally used.
As a method for activating the carbide after the carbonization treatment, for example, a gas activation method of firing using an activation gas such as water vapor, carbon dioxide, oxygen, and an alkali metal activation method of performing a heat treatment after mixing with an alkali metal compound are possible. However, an alkali metal activation method is preferable for producing activated carbon having a high specific surface area.
In this activation method, a carbide and an alkali metal compound such as KOH and NaOH are mixed at a mass ratio of carbide: alkali metal compound of 1: 1 or more (the amount of alkali metal compound is equal to or less than the amount of carbide). After heating the mixture in an inert gas atmosphere at a temperature of 600 to 900 ° C. for 0.5 to 5 hours, the alkali metal compound is washed and removed with acid and water, and then dried. I do.

In order to increase the amount of micropores and not increase the amount of mesopores, it is advisable to increase the amount of carbide during activation and mix with KOH. In order to increase both pore amounts, it is preferable to use a large amount of KOH. In order to mainly increase the mesopore amount, it is preferable to perform the steam activation after performing the alkali activation treatment.
The average particle size of the activated carbon 2 is preferably 1 μm or more and 30 μm or less. More preferably, it is 2 μm or more and 20 μm or less.

Each of the activated carbons 1 and 2 may be one type of activated carbon or a mixture of two or more types of activated carbons, each of which may indicate the above-described characteristic values as a whole mixture.
As the activated carbons 1 and 2, either one of them may be selected and used, or both may be used in combination.
As the positive electrode active material, a material other than the activated carbons 1 and 2 (for example, activated carbon not having the specific V1 and / or V2, or a material other than activated carbon (for example, a composite oxide of lithium and a transition metal)) is used. May be included. In the illustrated embodiment, the content of activated carbon 1, the content of activated carbon 2, or the total content of activated carbons 1 and 2 is preferably more than 50% by mass of all the positive electrode active materials, and more preferably 70% by mass or more. , 90% by mass or more, and most preferably 100% by mass.

[Negative electrode active material]
The negative electrode active material contains a carbon material capable of inserting and extracting lithium ions. As the negative electrode active material, only this carbon material may be used, or in addition to this carbon material, another material that stores and releases lithium ions may be used in combination. Examples of the other material include a lithium-titanium composite oxide and a conductive polymer. In the illustrated embodiment, the content of the carbon material capable of inserting and extracting lithium ions is preferably 50% by mass or more, more preferably 70% by mass or more, based on the total amount of the negative electrode active material. Although it can be 100% by mass, it is preferably, for example, 90% by mass or less, and may be 80% by mass or less, from the viewpoint of favorably obtaining the effect of the combined use of other materials.
Examples of the carbon material capable of inserting and extracting lithium ions include hard carbon, easily graphitic carbon, and composite porous carbon material.
Further preferred examples of the negative electrode active material are composite porous carbon materials 1, 2, and 3 formed by depositing a carbon material on the surface of activated carbon, which will be described later, which are advantageous in terms of the resistance of the negative electrode. The composite porous carbon materials 1, 2, and 3 may be used alone or in a combination of two or more. Further, as the carbon material in the negative electrode active material, only one or more selected from the composite porous carbon materials 1, 2, and 3 may be used, or the carbon material selected from the composite porous carbon materials 1, 2, and 3 may be used. Other carbon materials may be used in combination with one or more of the above-described carbon materials.

Hereinafter, the above-described composite porous materials 1, 2, and 3, and other carbon materials will be individually and sequentially described.
[Composite porous material 1]
The composite porous material 1 is a composite porous material defined by the following mesopore volume Vm1 and micropore volume Vm2.
The composite porous material 1 has Vm1 (cc / g) of the amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method, and micropores derived from pores having a diameter of less than 20 ° calculated by the MP method. When the amount is Vm2 (cc / g), the material satisfies 0.010 ≦ Vm1 ≦ 0.250, 0.001 ≦ Vm2 ≦ 0.200, and 1.5 ≦ Vm1 / Vm2 ≦ 20.0.
The composite porous material can be obtained, for example, by subjecting activated carbon and a carbon material precursor to coexistence and heat-treating them.

  The activated carbon used as a raw material of the composite porous material 1 is not particularly limited as long as the obtained composite porous material 1 exhibits desired characteristics. For example, commercially available products obtained from various raw materials such as petroleum, coal, plant, and polymer can be used. In particular, it is preferable to use activated carbon powder having an average particle size of 1 μm or more and 15 μm or less. This average particle size is more preferably 2 μm or more and 10 μm or less.

  The carbon material precursor used as a raw material of the composite porous material 1 is an organic material that can cause a carbon material to adhere to activated carbon by heat treatment. The carbon material precursor may be a solid, a liquid, or a substance soluble in a solvent. Examples of such a carbon material precursor include pitch, mesocarbon microbeads, coke, and a synthetic resin (eg, a phenol resin). Among these carbon material precursors, it is preferable to use an inexpensive pitch in terms of manufacturing cost. Pitch is roughly classified into petroleum pitch and coal pitch. Examples of the petroleum pitch include crude oil distillation residue, fluid catalytic cracking residue (decant oil and the like), bottom oil derived from a thermal cracker, ethylene tar obtained in naphtha cracking, and the like.

  When the pitch is used, the composite porous material is subjected to a heat treatment in the presence of the activated carbon in the presence of the pitch, and a volatile component or a pyrolysis component of the pitch is thermally reacted on the surface of the activated carbon to deposit the carbon material on the activated carbon. Thereby, the composite porous material 1 is obtained. In this case, at a temperature of about 200 to 500 ° C., the deposition of the volatile component or the pyrolysis component of the pitch into the activated carbon pores proceeds, and at 400 ° C. or higher, a reaction in which the deposited component becomes a carbon material proceeds. . The peak temperature (maximum temperature reached) during the heat treatment is appropriately determined depending on the characteristics of the obtained composite porous material 1, the thermal reaction pattern, the thermal reaction atmosphere, and the like, but is preferably 400 ° C. or higher, and more preferably. Is from 450 ° C to 1,000 ° C, more preferably from about 500 to 800 ° C. The time for maintaining the peak temperature during the heat treatment may be 30 minutes to 10 hours, preferably 1 hour to 7 hours, and more preferably 2 hours to 5 hours. For example, when heat treatment is performed at a peak temperature of about 500 to 800 ° C. for 2 to 5 hours, it is considered that the carbon material deposited on the surface of the activated carbon is a polycyclic aromatic hydrocarbon.

The softening point of the pitch used as the carbon material precursor is preferably from 30 ° C. to 250 ° C., and more preferably from 60 ° C. to 130 ° C. When the softening point of the pitch is 30 ° C. or more, there is no hindrance in handling properties, and it is possible to prepare with high precision. When this value is 250 ° C. or less, a relatively large amount of low molecular compounds is present, and it is possible to adhere to relatively fine pores in activated carbon.
As a specific method for producing the above composite porous material, for example, heat treatment of activated carbon in an inert atmosphere containing a hydrocarbon gas volatilized from a carbon material precursor, and depositing the carbon material in the gas phase Method. Further, a method in which activated carbon and a carbon material precursor are preliminarily mixed and heat-treated, or a method in which a carbon material precursor dissolved in a solvent is applied to activated carbon and dried, and then heat-treated is also possible.

  The composite porous material 1 is obtained by depositing a carbon material on the surface of activated carbon. The pore distribution after depositing the carbon material inside the pores of the activated carbon is important. It can be defined by the amount of micropores. In the present embodiment, in particular, the ratio of mesopore amount / micropore amount is important together with the absolute values of the mesopore amount and micropore amount. That is, in one embodiment of the present invention, the amount of mesopores derived from pores having a diameter of 20 to 500 mm in the composite porous material 1 calculated by the BJH method is Vm1 (cc / g), and the diameter calculated by the MP method. When the micropore amount derived from pores smaller than 20 ° is Vm2 (cc / g), 0.010 ≦ Vm1 ≦ 0.250, 0.001 ≦ Vm2 ≦ 0.200, and 1.5 ≦ Vm1 / Vm2 It is preferred that ≦ 20.0.

  The mesopore volume Vm1 is more preferably 0.010 ≦ Vm1 ≦ 0.225, and further preferably 0.010 ≦ Vm1 ≦ 0.200. The micropore volume Vm2 is more preferably 0.001 ≦ Vm2 ≦ 0.150, and even more preferably 0.001 ≦ Vm2 ≦ 0.100. The ratio of mesopores / micropores is more preferably 1.5 ≦ Vm1 / Vm2 ≦ 15.0, and even more preferably 1.5 ≦ Vm1 / Vm2 ≦ 10.0. When the mesopore amount Vm1 is equal to or lower than the upper limit (Vm1 ≦ 0.250), high charge / discharge efficiency for lithium ions can be maintained, and the mesopore amount Vm1 and the micropore amount Vm2 are equal to or higher than the lower limit (0.010 ≦ Vm1, 0. 001 ≦ Vm2), high output characteristics can be obtained.

Ion conductivity is higher in micro mesopores than in micropores. Therefore, in order to obtain high output characteristics, the amount of mesopores is required. On the other hand, impurities such as moisture, which are considered to have an adverse effect on the durability of the power storage element, are not easily desorbed in the micropore having a small diameter. Therefore, in order to obtain high durability, it is considered necessary to control the amount of micropores. Therefore, it is important to control the ratio between the amount of mesopores and the amount of micropores. When this value is not less than the lower limit (1.5 ≦ Vm1 / Vm2) (that is, the carbon material adheres to the micropores more than the mesopores of the activated carbon, and the mesopore amount of the composite porous material after the deposition is large, When the amount of micropores is small), both high energy density and high output characteristics and high durability (cycle characteristics, float characteristics, etc.) are compatible. When the ratio between the mesopore amount and the micropore amount is equal to or less than the upper limit (Vm1 / Vm2 ≦ 20.0), high output characteristics can be obtained.
In the present invention, the method of measuring the mesopore amount Vm1 and the micropore amount Vm2 is the same as the above-described method of measuring the activated carbon in the positive electrode active material.

In one embodiment of the present invention, as described above, the ratio of the amount of mesopores / the amount of micropores after the carbon material is deposited on the surface of the activated carbon is important. In order to obtain a composite porous material having a pore distribution range specified in the present invention, the pore distribution of activated carbon used as a raw material is important.
In the activated carbon used for forming the composite porous material as the negative electrode active material, the amount of mesopores derived from pores having a diameter of 20 to 500 mm calculated by the BJH method is V1 (cc / g), and the diameter calculated by the MP method. When the micropore amount derived from pores smaller than 20 ° is V2 (cc / g), 0.050 ≦ V1 ≦ 0.500, 0.005 ≦ V2 ≦ 1.000, and 0.2 ≦ V1 / It is preferable that V2 ≦ 20.0.
The mesopore volume V1 is more preferably 0.050 ≦ V1 ≦ 0.350, and even more preferably 0.100 ≦ V1 ≦ 0.300. The micropore volume V2 is more preferably 0.005 ≦ V2 ≦ 0.850, and even more preferably 0.100 ≦ V2 ≦ 0.800. The ratio of mesopores / micropores is more preferably 0.22 ≦ V1 / V2 ≦ 15.0, and even more preferably 0.25 ≦ V1 / V2 ≦ 10.0. When the mesopore volume V1 of the activated carbon is 0.500 or less and the micropore volume V2 is 1.000 or less, an appropriate amount of carbon is required to obtain the pore structure of the composite porous material 1 of the present embodiment. Since it is sufficient to apply the material, the pore structure tends to be easily controlled. For the same reason, when the mesopore volume V1 of the activated carbon is 0.050 or more and the micropore volume V2 is 0.005 or more, V1 / V2 is 0.2 or more and V1 / V2 is 20 or more. Even if it is not more than 0.0, the pore structure of the composite porous material 1 of the present embodiment can be easily obtained from the pore distribution of the activated carbon.

The average particle size of the composite porous material 1 in the present embodiment is preferably 1 μm or more and 10 μm or less. The lower limit is more preferably 2 μm or more, and still more preferably 2.5 μm or more. The upper limit is more preferably 6 μm or less, and still more preferably 4 μm or less. When the average particle size is 1 μm or more and 10 μm or less, good durability is maintained.
In the composite porous material 1 described above, the atomic ratio of hydrogen atoms / carbon atoms (hereinafter, also referred to as “H / C”) is preferably 0.05 or more and 0.35 or less, and 0.05 or more. More preferably, it is 0.15 or less. When H / C is 0.35 or less, the structure (typically, a polycyclic aromatic conjugated structure) of the carbon material deposited on the activated carbon surface is sufficiently developed, so that the capacity (energy density) ) And charge / discharge efficiency are increased. On the other hand, when H / C is 0.05 or more, carbonization does not proceed excessively, so that a good energy density is obtained. H / C is measured by an elemental analyzer.

The composite porous material 1 preferably has an amorphous structure derived from activated carbon as a raw material and a crystal structure mainly derived from the deposited carbon material. A structure having low crystallinity is preferable to exhibit high output characteristics, and a structure having high crystallinity is preferable to maintain reversibility in charge and discharge. From such a viewpoint, the composite porous material 1 has a plane distance d ₀₀₂ of the (002) plane measured by an X-ray wide-angle diffraction method of 3.60 ° to 4.00 °, and a half-value width of this peak. The crystallite size Lc in the c-axis direction obtained from the above is preferably 8.0 ° or more and 20.0 ° or less, d ₀₀₂ is 3.60 ° or more and 3.75 ° or less, and c obtained from the half-value width of this peak. More preferably, the crystallite size Lc in the axial direction is not less than 11.0 ° and not more than 16.0 °.

[Composite porous material 2]
The composite porous material 2 is a composite porous material in which a carbon material is applied on the surface of activated carbon, and has a mass ratio of the carbon material to the activated carbon of 10% or more and 60% or less. This mass ratio is preferably 15% or more and 55% or less, more preferably 18% or more and 50% or less, and particularly preferably 20% or more and 47% or less. When the mass ratio of the carbon material is 10% or more, the micropores of the activated carbon can be appropriately filled with the carbon material, and the charge / discharge efficiency of lithium ions is improved, so that the durability is not impaired. . When the mass ratio of the carbon material is 60% or less, the specific surface area can be increased by appropriately holding the pores of the activated carbon. Therefore, the pre-doping amount of lithium ions can be increased. As a result, high output density and high durability can be maintained even if the negative electrode is thinned.

The specific surface area in BET method of the composite porous material ^2, 350m ² / ^g~1,500m 2 / g are ^preferred, 400m ² / ^g~1,100m 2 / g is more preferable. When the specific surface area is 350 m ² / g or more, it can be said that the composite porous material 2 appropriately holds pores. Therefore, as a result of increasing the pre-doping amount of lithium ions, it is possible to reduce the thickness of the negative electrode. On the other hand, when the specific surface area is 1,500 m ² / g or less, it can be said that the micropores of the activated carbon are appropriately filled. Therefore, the charge / discharge efficiency of lithium ions is improved, and the durability is not impaired.
The composite porous material 2 can be obtained, for example, by performing a heat treatment in a state where activated carbon and a carbon material precursor coexist. Specific examples of the activated carbon and the carbon material precursor and the heat treatment method for producing the composite porous material 2 are the same as those described above for the composite porous material 1, and thus description thereof will not be repeated here.
However, the softening point of the pitch used to obtain the composite porous material 2 is preferably from 30 ° C to 100 ° C, more preferably from 35 ° C to 85 ° C. If the softening point of the pitch is 30 ° C. or more, there is no hindrance to the handling properties, and it is possible to prepare with high precision. If this value is 100 ° C. or less, since many low molecular compounds are present, it is possible to adhere to fine pores in activated carbon.

The composite porous material 2 is obtained by depositing a carbon material on the surface of activated carbon. The distribution of pores after depositing the carbon material inside the pores of activated carbon is important. This pore distribution can be defined by the amount of mesopores and the amount of micropores. That is, the composite porous material 2 has a mesopore amount derived from pores having a diameter of not less than 20 ° and not more than 500 ° calculated by the BJH method as Vm1 (cc / g) and a mesopore amount derived from pores having a diameter less than 20 ° calculated by the MP method. When the micropore volume is Vm2 (cc / g), it is preferable to satisfy any one of the following three regions:
(1) 0.010 ≦ Vm1 ≦ 0.300 and 0.010 ≦ Vm2 ≦ 0.200
(2) 0.010 ≦ Vm1 ≦ 0.200 and 0.200 ≦ Vm2 ≦ 0.400
(3) 0.010 ≦ Vm1 ≦ 0.100 and 0.400 ≦ Vm2 ≦ 0.650
Regarding the above (1), it is more preferable that 0.050 ≦ Vm1 ≦ 0.300 and 0.010 ≦ Vm2 ≦ 0.200.

When the mesopore amount Vm1 is equal to or less than the upper limit (Vm1 ≦ 0.300), the specific surface area of the composite porous material can be increased, and the pre-doping amount of lithium ions can be increased. In addition to this, the bulk density of the negative electrode can be further increased, so that the negative electrode can be made thinner. When the micropore amount Vm2 is equal to or less than the upper limit (Vm1 ≦ 0.650), high charge / discharge efficiency for lithium ions can be maintained. On the other hand, if the mesopore amount Vm1 and the micropore amount Vm2 are not less than the lower limit (0.010 ≦ Vm1, 0.010 ≦ Vm2), high output characteristics can be obtained.
In the present embodiment, the method for measuring the mesopore amount Vm1 and the micropore amount Vm2 is the same as the above-described method for measuring the activated carbon in the positive electrode active material.
Regarding the average particle diameter, the atomic ratio of hydrogen atoms / carbon atoms (H / C), and the crystal structure of the composite porous material 2 in the present embodiment, the description has been given above for the composite porous material 1. It is used as it is.

  In the composite porous material 2, the average pore diameter is preferably 28 ° or more, more preferably 30 ° or more, from the viewpoint of high output characteristics. On the other hand, from the viewpoint of increasing the energy density, it is preferably at most 65 °, more preferably at most 60 °. In the present embodiment, the average pore diameter is determined by dividing the total pore volume per mass obtained by measuring each equilibrium adsorption amount of nitrogen gas at each relative pressure under liquid nitrogen temperature by the BET specific surface area. Means something.

[Composite porous material 3]
The composite porous material 3 is a composite carbon material containing carbon black and a carbon material. BET specific surface area of the composite porous material 3 is preferably at 100 m ² / g or more and more preferably 100 m ² / g or more 350m ² / g or less. This BET specific surface area is more preferably from 150 m ² / g to 300 m ² / g, and particularly preferably from 180 m ² / g to 240 m ² / g.
There is a positive correlation between the BET specific surface area of the composite porous material 3 and the initial charge capacity of lithium ions per unit mass of the composite porous material 3 and the allowable amount of pre-doping. It is presumed that this is because the density of lithium ion storage sites other than between the carbon mesh planes, such as the edge plane of the carbon mesh plane and the defect site, increases as the BET specific surface area increases. For this reason, if the BET specific surface area is 100 m ² / g or more, the pre-doping amount can be sufficiently increased, and the negative electrode active material layer can be made thin. In addition, even when the negative electrode active material layer is thinned, high output characteristics can be exhibited because there are sufficiently many sites (reaction fields) responsible for doping / undoping of lithium ions. On the other hand, if the composite porous material 3 has a BET specific surface area of 350 m ² / g or less, it has excellent coatability when forming the negative electrode active material layer.

The composite porous material 3 is obtained by sintering or graphitizing a kneaded product obtained by kneading carbon black and a precursor for providing the carbon material, and then pulverizing the mixture to an average particle diameter (D50) of 1 to 20 μm. It is manufactured by
The composite porous material 3 has an average particle size of 12 to 300 nm as measured by an electron microscope, and a carbon black having a BET specific surface area of 200 to 1,500 m ² / g;
The kneaded product obtained by kneading with the precursor of the carbon material is fired or graphitized at 800 ° C. to 3,200 ° C., and then pulverized to an average particle diameter (D50) of 1 to 20 μm. it can.

  The amount of the carbon material precursor used in the production of the composite porous material 3 is preferably 30 parts by mass or more and 200 parts by mass or less based on 100 parts by mass of the carbon black. More preferably, it is 30 parts by mass or more and 150 parts by mass or less. When this ratio is 30 parts by mass or more, high output characteristics can be realized by the effect of compounding. On the other hand, if this ratio is 200 parts by mass or less, an appropriate BET specific surface area can be maintained, and the pre-doping amount of lithium ions can be increased. The negative electrode active material may be used alone or in combination of two or more.

As the carbon black used as a raw material of the composite porous material 3, various commercially available brands can be used as long as the obtained composite carbon material exhibits desired characteristics.
As described above, the average particle size of carbon black used as a raw material measured by an electron microscope is preferably 12 to 300 nm. As a method for measuring the particle size of the carbon black, several fields of a photograph having a magnification of several tens of thousands were photographed with an electron microscope, and the particle size of the particles in the field of view was determined to 2,000 using a fully automatic image processing device or the like. A method of measuring and measuring about 3,000 pieces is used (Carbon Black Handbook, 3rd edition (Book Publishing Co., Ltd., published on May 25, 1973, page 4)). In the present embodiment, carbon black having an average particle size of 12 to 300 nm determined by an electron microscope can be used. According to catalog values of various brands available on the market, most carbon blacks have a particle size in this range.

As a precursor of the carbon material, petroleum or coal pitch, or a resin such as a phenol resin, a furan resin, or divinylbenzene can be used. These can be used singly or in combination of two or more. Among these precursors, it is preferable to use an inexpensive pitch in terms of manufacturing cost.
The above carbon black and the above carbon material precursor are kneaded using an appropriate kneading machine such as a heating kneader. After kneading, the mixture is fired or graphitized at 800 ° C. to 3,200 ° C. in a non-oxidizing atmosphere. If the heat treatment temperature is lower than 800 ° C., the functional groups on the particle surface remain. In the obtained lithium ion capacitor, this residual functional group reacts with Li ions, so that the capacity loss increases and an inflection point occurs near the discharge curve 1V, which is not preferable. If the heat treatment temperature exceeds 3,400 ° C., the graphitized particles will sublime, so that firing or graphitizing at a temperature of 3,200 ° C. is the limit.

Next, the product obtained by firing or graphitizing as described above is pulverized so that the average particle size (D50) is preferably 1 to 20 μm. The lower limit of the average particle diameter (D50) is more preferably 5 μm or more, and further preferably 7 μm or more. Further, the upper limit of the average particle diameter (D50) is more preferably 20 μm or less, and further preferably 15 μm or less. When the average particle diameter (D50) is 5 μm or more, the electrode peel strength of the negative electrode when the composite carbon material 3 is used as a negative electrode active material is sufficiently large. This is because the negative electrode active material, the conductive filler, and the binder are dispersed in a solvent to form a slurry, and the negative electrode active material layer is coated on the negative electrode current collector and dried. It is presumed that this is because it is possible to alleviate the cracks and suppress cracks in the electrodes. As another method for improving the peel strength of the electrode, a method of changing the type and amount of the binder is known. However, when a composite carbon material having a BET specific surface area of 100 m ² / g or more is used for the negative electrode active material, a significant improvement in the electrode peel strength of the negative electrode by changing the type and amount of the binder cannot be confirmed. On the other hand, when the average particle diameter (D50) is 20 μm or less, when the negative electrode active material layer is applied on the negative electrode current collector in the same manner as described above, no streak or the like is generated, and the coatability is excellent. .
The particle size of the pulverized particles is a value measured by a laser diffraction method.
After the pulverization, if necessary, recalcination or regraphitization may be performed at 800 to 3,200 ° C.
The composite carbon material 3, which is the negative electrode active material in the present invention, is an aggregate formed by binding carbon material to carbon black, and is a porous carbon material having a specific pore structure and a graphite material.

The pore structure of the composite carbon material 3 can be known from the isothermal adsorption line in adsorption and desorption of nitrogen gas.
In the isothermal adsorption line in the adsorption and desorption of nitrogen gas, the change in the amount of adsorbed nitrogen gas is small until the phase pressure (P / P0) of the nitrogen gas is around 0.8, and increases sharply when it exceeds 0.8. In the composite carbon material of the present invention, in the isotherm line in the adsorption and desorption of nitrogen gas, the nitrogen gas adsorption amount at a relative pressure (P / P0) of nitrogen around 0.99 is 10 to 1,000 ml / g. Preferably, there is. This requirement indicates that, in the composite carbon material of the present invention, the pore volume of micropores having a pore diameter of 2 nm or less is 20% or less of the total pore volume.

  The composite carbon material 3 according to the present invention has a specific pore structure as described above, and thus functions as a negative electrode active material that exhibits both high output characteristics and high energy density. The raw materials of the composite carbon material are inexpensive carbon black and a carbon material precursor (preferably pitch), which are obtained by a simple process of pulverizing the kneaded product after firing or graphitization. is there. Furthermore, the pore structure can be controlled by selecting the brand of carbon black and the mixing ratio with the carbon material precursor.

[Other carbon materials]
Other carbon materials contained in the negative electrode active material include, for example, graphite, easily graphitizable carbon material, non-graphitizable carbon material, amorphous carbon material such as polyacene-based material, carbon nanotube, fullerene, carbon nanophone, fiber And the like, which do not correspond to any of the composite porous materials 1 and 2 described above.
When the negative electrode active material contains another carbon material, the usage ratio of the other carbon material is preferably 50% by mass or less, and more preferably 20% by mass or less based on the total carbon material. More preferred.

[Other components of negative electrode active material layer]
To the negative electrode active material layer, for example, a conductive filler, a binder, and the like can be added in addition to the negative electrode active material, if necessary.
Although the kind of the conductive filler is not particularly limited, examples thereof include acetylene black, Ketjen black, and vapor grown carbon fiber. The addition amount of the conductive filler is preferably, for example, 0 to 30% by mass based on the negative electrode active material.
The binder is not particularly limited. For example, PVdF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), a styrene-butadiene copolymer, or the like can be used. The addition amount of the binder is preferably, for example, in the range of 3 to 20% by mass based on the negative electrode active material.

[Pre-doping of negative electrode active material]
The negative electrode active material is preferably pre-doped with lithium ions. In a particularly preferred embodiment, the negative electrode active material contains the composite porous material 2 or 3, and the composite porous material 2 or 3 is pre-doped with lithium ions. This pre-doping amount is preferably 1,050 mAh / g or more and 2,050 mAh / g or less, more preferably 1,100 mAh / g or more and 2,000 mAh / g or less per unit mass of the composite porous material 2 or 3. And more preferably 1,200 mAh / g or more and 1,700 mAh / g or less, and particularly preferably 1,300 mAh / g or more and 1,600 mAh / g or less.

By pre-doping with lithium ions, the potential of the negative electrode decreases, the cell voltage increases when combined with the positive electrode, and the capacity of the positive electrode increases. for that reason. The capacity and energy density increase. If the pre-doping amount is more than 1,050 mAh / g, lithium ions in the negative electrode material are satisfactorily pre-doped even at irreversible sites that cannot be desorbed once the lithium ions are inserted, and furthermore, the negative electrode activity for a desired lithium amount is reduced. The amount of substance can be reduced. Therefore, the thickness of the negative electrode can be reduced, and high durability, good output characteristics, and high energy density can be obtained. Further, as the pre-doping amount increases, the negative electrode potential decreases, and the durability and the energy density improve. When the pre-doping amount is 2,050 mAh / g or less, there is no possibility that side effects such as deposition of lithium metal will occur.
As a method of pre-doping the negative electrode with lithium ions, a known method can be used. For example, after molding a negative electrode active material into an electric body, using the negative electrode as a working electrode and metallic lithium as a counter electrode, fabricating an electrochemical cell combining a non-aqueous electrolytic solution, and electrochemically pre-doping lithium ions Method. It is also possible to pre-dope the negative electrode with lithium ions by pressing a metal lithium foil on the negative electrode body and putting it in a non-aqueous electrolyte.
By doping the negative electrode active material with lithium ions, the capacity and operating voltage of the obtained power storage element can be favorably controlled.

[Common elements of positive and negative electrodes]
As common matters for the positive electrode and the negative electrode, (1) the components other than the active material in the active material layer, (2) the structure of the current collector, and (3) the structure of the electrode body will be sequentially described below.
(1) Components other than the active material in the active material layer The active material layers of the positive electrode and the negative electrode each contain, in addition to the above-mentioned active material, a known component contained in the active material layer in a known lithium ion battery, a capacitor, or the like. Further, it can be contained. The known components include, for example, a binder, a conductive filler, a thickener, and the like, and the type thereof is not particularly limited.
Hereinafter, components other than the active material contained in the active material layers of the positive electrode and the negative electrode in the nonaqueous lithium-type energy storage device of the present embodiment will be described in detail.

The active material layer can include a conductive filler (for example, carbon black), a binder, and the like as necessary.
The amount of the conductive filler to be used is preferably from 0 to 30 parts by mass, more preferably from 1 to 20 parts by mass, per 100 parts by mass of the active material. From the viewpoint of high output density, it is preferable to use a conductive filler, but when the amount is 30 parts by mass or less, the ratio of the amount of the active material in the active material layer increases, and the output per volume also increases. This is preferable because the density tends to increase.
In the active material layer, a binder is used in order to fix the above-mentioned active material and the conductive filler used as needed on the current collector as the active material layer. As the binder, for example, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), fluororubber, styrene-butadiene copolymer, cellulose derivative and the like can be used. The amount of the binder used is preferably in the range of 3 to 20 parts by mass, more preferably 5 to 15 parts by mass, per 100 parts by mass of the active material. When the amount of the binder used is 20 parts by mass or less, the surface of the active material is not covered with the binder. Therefore, it is preferable because ions enter and exit the active material layer quickly and a high output density tends to be easily obtained. On the other hand, when the amount of the binder used is 3 parts by mass or more, the active material layer tends to be easily fixed on the current collector, which is preferable.

(2) Current Collector As the current collector, a general current collector usually used in a power storage element can be used. The current collector is preferably a metal foil that does not deteriorate due to elution into the electrolytic solution, reaction with the electrolytic solution, or the like. Such a metal foil is not particularly limited, and examples thereof include a copper foil and an aluminum foil. In the power storage element of this embodiment, it is preferable that the positive electrode current collector be an aluminum foil and the negative electrode current collector be a copper foil.
The current collector may be a metal foil having no holes, or a metal foil having a through hole (for example, a punching metal through hole) or an opening portion (for example, an opening metal opening portion). The thickness of the current collector is not particularly limited, but is preferably 1 to 100 μm. When the thickness of the current collector is 1 μm or more, the shape and strength of the electrode body (the positive electrode and the negative electrode in the present invention) formed by fixing the active material layer to the current collector can be preferably maintained. On the other hand, when the thickness of the current collector is 100 μm or less, the weight and volume of the power storage element become appropriate, and the performance per weight and volume tends to be high, which is preferable.

(3) Configuration of electrode body The electrode body is formed by providing an active material layer on one side or both sides of a current collector. In a typical embodiment, the active material layer is fixed to the current collector.
The electrode body can be manufactured by a known electrode manufacturing technology such as a lithium ion battery and an electric double layer capacitor. For example, various materials including an active material are formed into a slurry with water or an organic solvent, the slurry is applied on a current collector, dried, and optionally pressed at room temperature or under heating to form an active material layer. Thus, it is obtained. Without using a solvent, various materials including an active material can be mixed in a dry manner, and the resulting mixture can be press-molded and then attached to a current collector using a conductive adhesive.

The thickness of the positive electrode active material layer is preferably 15 μm or more and 100 μm or less, more preferably 20 μm or more and 85 μm or less per one surface. When the thickness is 15 μm or more, a sufficient energy density as a capacitor can be exhibited. On the other hand, if the thickness is 100 μm or less, high input / output characteristics can be obtained as a capacitor.
The thickness of the negative electrode active material layer is preferably from 20 μm to 45 μm, more preferably from 25 μm to 40 μm, on one side. When the thickness is 20 μm or more, good charge / discharge capacity can be exhibited. On the other hand, if the thickness is 45 μm or less, the energy density can be increased by reducing the cell volume. When the composite porous material 2 is used as the negative electrode active material, the thickness of the negative electrode active material layer is preferably 20 μm or more and 45 μm or less, more preferably 20 to 40 μm per side, from the viewpoint of the resistance of the negative electrode, More preferably, it is 25 to 35 μm.
In the case where the current collector has holes, the thicknesses of the active material layers of the positive electrode and the negative electrode refer to the average values of the thickness of one side of the current collector without holes.
The bulk density of the electrode active material layer in the storage element electrode of the present invention is preferably from 0.30 g / cm ^{3 to} 1.2 g / cm ³ . When the bulk density is 0.30 g / cm ³ or more, the capacity of the electrode per volume can be increased, and downsizing of the power storage element can be achieved. When the bulk density is 1.2 g / cm ³ or less, it is considered that the diffusion of the electrolyte in the voids in the electrode active material layer becomes sufficient, and the charge / discharge characteristics at a large current are improved. Therefore, it is more preferably in the range of 0.35 g / cm ³ or more and 1.0 g / cm ³ or less.
The bulk density of the positive electrode active material layer, in order to further increase the charge-discharge characteristics at a large current, more preferably to 0.70 g / cm ³ or less, and particularly preferably 0.65 g / cm ³ or less.
The bulk density of the negative electrode active material layer is more preferably 0.60 g / cm ³ or more, particularly preferably 0.70 g / cm ³ , from the viewpoint of developing good conductivity between the active materials and maintaining high strength. cm ³ or more.

[Separator]
The positive electrode body and the negative electrode body molded as described above are laminated or wound around with a separator interposed therebetween to form an electrode laminate having the positive electrode body, the negative electrode body and the separator.
As the separator, a polyethylene microporous film or a polypropylene microporous film used for a lithium ion secondary battery, a cellulose nonwoven paper used for an electric double layer capacitor, or the like can be used.
The thickness of the separator is preferably from 10 μm to 50 μm. The thickness of 10 μm or more is preferable because self-discharge due to internal micro short circuit tends to be small. On the other hand, when the thickness is 50 μm or less, the output characteristics of the power storage element tend to be high, which is preferable.

[Outer body]
As the exterior body, a metal can, a laminated film, or the like can be used.
The metal can is preferably made of aluminum.
As the above-mentioned laminated film, a film obtained by laminating a metal foil and a resin film is preferable, and a three-layer structure composed of an outer layer resin film / metal foil / interior resin film is exemplified. The outer resin film is for preventing the metal foil from being damaged by contact or the like, and a resin such as nylon or polyester can be suitably used. The metal foil is for preventing permeation of moisture and gas, and foils of copper, aluminum, stainless steel and the like can be suitably used. The interior resin film protects the metal foil from the electrolytic solution contained therein and is used for melting and sealing at the time of heat sealing of the exterior body, and polyolefin, acid-modified polyolefin and the like can be suitably used.

[Non-aqueous lithium-type storage element]
The non-aqueous lithium-type energy storage device according to the present embodiment is configured such that the electrode laminate and the non-aqueous electrolyte obtained as described above are housed in the outer package.
The non-aqueous lithium-type energy storage device according to the present embodiment has both high input / output characteristics and high durability at high temperatures, as will be specifically verified in Examples described later.

Hereinafter, the present embodiment will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.
<Example 1>
[Preparation of positive electrode body]
The crushed coconut shell carbide was carbonized in a small carbonization furnace at 500 ° C. for 3 hours in nitrogen to obtain a carbide. The obtained carbide was put into the activation furnace, and steam of 1 kg / h was introduced into the activation furnace while being heated in the preheating furnace, and the temperature was raised to 900 ° C. over 8 hours to activate. The activated carbide was taken out and cooled under a nitrogen atmosphere to obtain activated activated carbon. The obtained activated carbon was washed with water for 10 hours and then drained. Then, after drying in an electric dryer maintained at 115 ° C. for 10 hours, pulverization was performed for 1 hour with a ball mill to obtain activated carbon 1.
The average particle size of the activated carbon 1 measured by using a laser diffraction type particle size distribution analyzer (SALD-2000J) manufactured by Shimadzu Corporation was 4.2 μm. Also, the pore distribution was measured using a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics. The mesopore volume (V1) calculated by QSDFT using the isotherm on the desorption side was 0.52 cc / g, and the micropore volume (V2) was 0.88 cc / g. The BET specific surface area determined by the BET one-point method was 2,360 m ² / g.
80.8 parts by mass of the activated carbon 1, 6.2 parts by mass of Ketjen black, 10 parts by mass of PVDF (polyvinylidene fluoride), 3.0 parts by mass of PVP (polyvinylpyrrolidone), and NMP (N-methyl) Pyrrolidone) to obtain a slurry. The obtained slurry is applied to one or both sides of a current collector made of an aluminum foil having a thickness of 15 μm, dried and pressed to obtain a positive electrode body having a thickness of 55 μm per one side of a positive electrode active material layer. Was.

[Production of negative electrode body]
For commercially available coconut shell activated carbon, the pore distribution was measured using nitrogen as an adsorbate using a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics. As described above, the mesopore amount was determined by the BJH method and the micropore amount was determined by the MP method using the desorption-side isotherm. As a result, the mesopore volume was 0.198 cc / g, the micropore volume was 0.695 cc / g, V1 / V2 = 0.29, and the average pore size was 21.2 °. The BET specific surface area determined by the BET one-point method was 1,780 m ² / g.
150 g of this coconut shell activated carbon is placed in a basket made of stainless steel mesh, placed on a stainless steel vat containing 270 g of coal-based pitch (softening point: 50 ° C.), and placed in an electric furnace (effective size in furnace: 300 mm × 300 mm × 300 mm) And heat-treated to obtain a composite porous material 1. This heat treatment was performed in a nitrogen atmosphere, the temperature was raised to 600 ° C. in 8 hours, and the temperature was maintained at the same temperature for 4 hours. Subsequently, after cooling to 60 ° C. by natural cooling, the composite porous material 1 serving as the negative electrode material was taken out of the furnace. When the obtained composite porous material 1 was measured in the same manner as the activated carbon 1, the BET specific surface area was 262 m ² / g, the mesopore volume (Vm1) was 0.1798 cc / g, and the micropore volume (Vm2) was 0. 0843 cc / g, Vm1 / Vm2 = 2.13.
83.4 parts by mass of the composite porous material 1, 8.3 parts by mass of acetylene black, 8.3 parts by mass of PVDF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone) were mixed, and the slurry was mixed. Obtained. The obtained slurry was applied to both sides of the expanded copper foil, dried, and pressed to obtain a negative electrode body having a negative electrode active material layer having a thickness on one side of 60 μm. A lithium metal foil equivalent to 760 mAh / g per unit mass of the composite porous material 1 was attached to one surface of the double-sided negative electrode body.

[Preparation of electrolyte solution]
As the organic solvent, ethylene carbonate (EC): methylethyl carbonate _{(EMC): HFE7000 (n-} C 3 F 7 OCH 3) a volume ratio of 33: 60: 7 mixed solvent used in, LiN the total electrolyte ( The respective electrolytes were so adjusted that the concentration ratio of SO ₂ F) ₂ and LiPF ₆ was 50:50 (molar ratio) and the sum of the concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ was 1.2 mol / L. The solution obtained by dissolving the salt was used as a non-aqueous electrolyte.
The concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ in the electrolyte solution prepared here were 0.6 mol / L and 0.6 mol / L, respectively.

[Assembly and performance of storage element]
The obtained electrode body was cut into 100 mm × 100 mm, and the uppermost surface and the lowermost surface used a single-sided positive electrode body, and further used 18 double-sided negative electrode bodies and 17 double-sided positive electrode bodies, Laminated with a nonwoven fabric separator made of cellulose (that is, a total of 36 sheets) between the body and the body. Thereafter, electrode terminals were connected to the negative electrode body and the positive electrode body to form an electrode laminate. This laminate was inserted into an outer package made of a laminate film, and the above nonaqueous electrolytic solution was injected to seal the outer package, thereby assembling a nonaqueous lithium-type power storage element.

[Measurement of capacitance]
The storage element obtained in the above step was charged to 3.8 V by constant current / constant voltage charging in which a constant voltage charging time of 1 hour was secured at a current value of 1.5 C, and then 1.5 C to 2.2 V. A constant current discharge was performed at a current value. From the capacitance Q and the voltage change at that time, the capacitance F obtained by calculation according to F = Q / (3.8-2.2) was 1,000F.

[Calculation of Ra · F]
The storage element obtained in the above step is charged at a constant current at an environmental temperature of 25 ° C. until the voltage reaches 3.8 V at a current value of 1.5 C, and thereafter, a constant current constant voltage charging in which a constant voltage of 3.8 V is applied. For a total of 2 hours. Subsequently, a constant current discharge was performed to 2.2 V at a current value of 50C. In the discharge curve (time-voltage) obtained at this time, when the voltage at the discharge time = 0 second obtained by extrapolating by linear approximation from the voltage values at the discharge time of 2 seconds and 4 seconds is E0. The internal resistance Ra was calculated by a calculation according to the following formula: drop voltage (ΔE) = 3.8−E0, and internal resistance Ra = ΔE / (50C (current value)).
The product Ra · F of the capacitance F and the internal resistance Ra was 1.30ΩF.

[Calculation of Rb / Ra]
The power storage element for which Ra · F was evaluated was stored at a cell voltage of 4.0 V and an ambient temperature of 60 ° C. for 2 months. Here, in order to maintain the cell voltage at 4.0 V, before storage and after the start of storage, 4.0 V charging at a current value of 1.5 C was performed for a total of 2 hours every week.
The storage element after storage for 2 months is charged at a constant current at an environmental temperature of 25 ° C. at a current value of 1.5 C until the voltage reaches 3.8 V, and then a constant current constant voltage of 3.8 V is applied. Charging was performed for a total of 2 hours. Subsequently, a constant current discharge was performed to 2.2 V at a current value of 50C. In the discharge curve (time-voltage) obtained at this time, when the voltage at the discharge time = 0 second obtained by extrapolating by linear approximation from the voltage values at the discharge time of 2 seconds and 4 seconds is E0. Then, the internal resistance Rb after storage was calculated by calculation in accordance with the drop voltage (ΔE) = 3.8−E0 and the internal resistance Rb = ΔE / (50C (current value)).
The ratio Rb / Ra calculated by dividing this Rb (Ω) by the internal resistance Ra (Ω) before storage obtained in the above [Calculation of Ra · F] was 1.35.

[Measurement of gas generated during storage]
Next, with respect to the electricity storage device obtained in the above step, the amount of gas generated when stored for 2 months at a cell voltage of 4.0 V and an ambient temperature of 60 ° C. was measured at 25 ° C. As a result, the gas generation amount was 9.0 × 10 ⁻³ cc / F.

[Nail penetration test]
A nail penetration test was performed on the electricity storage device obtained in the above step under the following conditions.
Testing machine: Shimadzu Autograph AG-X
Nail: φ2.5mm-SUS304
Evaluation method: The power storage element was fixed horizontally, and the amount of smoke generated after the nail was pierced at a central portion of the power storage element at a speed of 10 mm / sec was visually observed.

<Examples 2 to 12 and Comparative Examples 1 to 6>
In [Preparation of electrolyte solution], an electrolyte solution was prepared in the same manner as in Example 1, except that the types and amounts of the organic solvent and the electrolyte salt were as described in Table 1, respectively.
Except that this electrolytic solution was used, a non-aqueous lithium-type energy storage device was produced in the same manner as in Example 1, and various evaluations were made.
The evaluation results are shown in Table 1.

<Example 13>
[Preparation of electrolyte solution]
As an organic solvent, a mixed solvent solution of ethylene carbonate (EC): methyl ethyl carbonate (EMC): HFE7000 at a volume ratio of 33: 63: 4 was used, and LiN (SO ₂ F) ₂ and LiPF ₆ were used with respect to the total electrolyte solution. The respective electrolyte salts were dissolved such that the concentration ratio was 75:25 (molar ratio) and the sum of the concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ was 1.2 mol / L. Further, as an additive, a solution obtained by dissolving 1,3-propane sultone (1,3-PS) in an amount of 1% by mass based on the total electrolytic solution was used as a non-aqueous electrolytic solution.
The concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ in the electrolyte solution prepared here were 0.9 mol / L and 0.3 mol / L, respectively.
[Assembly and performance of storage element]
A non-aqueous lithium-type energy storage device was prepared in the same manner as in Example 1 except that the electrolyte solution prepared above was used, and various evaluations were made.
The evaluation results are shown in Table 1.

<Examples 14 to 24>
In [Preparation of electrolyte solution], an electrolyte solution was prepared in the same manner as in Example 28, except that the types and amounts of the organic solvent, the electrolyte salt, and the additives were as described in Table 1, respectively.
Except that this electrolytic solution was used, a non-aqueous lithium-type energy storage device was produced in the same manner as in Example 1, and various evaluations were made.
The evaluation results are shown in Table 1.

The abbreviations of the organic solvent and the additives in Table 1 have the following meanings.
[Organic solvent]
(A) component EC: ethylene carbonate PC: propylene carbonate (b) component EMC: methyl ethyl carbonate (c) component HFE7000: C ₃ F ₇ OCH ₃
HFE7100: C ₄ F ₉ OCH _{3
HFE7200: C 4 F 9 OC 2} H 5
[Additive]
1,3-PS: 1,3-propane sultone PN: ethoxypentafluorocyclotriphosphazene

<Example 25>
[Preparation of positive electrode body]
The phenol resin was carbonized at 600 ° C. for 2 hours in a baking furnace under a nitrogen atmosphere. The obtained fired product was pulverized with a ball mill and classified to obtain a carbide having an average particle size of 7 μm.
This carbide and KOH were mixed at a mass ratio of 1: 5, and heated in a firing furnace at 800 ° C. for 1 hour in a nitrogen atmosphere to activate. Then, after washing with stirring in diluted hydrochloric acid adjusted to a concentration of 2 mol / L for 1 hour, boiling washing was performed in distilled water until the pH became stable between pH 5 and 6, and then drying was performed to prepare activated carbon 2. .
When the activated carbon 2 was measured in the same manner as in Example 1, the mesopore volume V1 was 1.50 cc / g, the micropore volume V2 was 2.28 cc / g, and the BET specific surface area was 3,627 m ² / g.
80.8 parts by mass of the activated carbon 2, 6.2 parts by mass of Ketjen black, 10 parts by mass of PVDF (polyvinylidene fluoride), 3.0 parts by mass of PVP (polyvinylpyrrolidone), and NMP (N-methylpyrrolidone) ) Was mixed to obtain a slurry. The obtained slurry is applied to one or both sides of a current collector made of an aluminum foil having a thickness of 15 μm, dried and pressed to obtain a positive electrode body having a thickness of 55 μm per one side of a positive electrode active material layer. Was.

[Production of negative electrode body]
Using a commercially available coconut shell activated carbon, a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics Co., Ltd., the pore distribution was measured using nitrogen as an adsorbate. Using the isotherm on the desorption side, the mesopore volume was determined by the BJH method, and the micropore volume was determined by the MP method. As a result, the mesopore volume was 0.198 cc / g, the micropore volume was 0.695 cc / g, V1 / V2 = 0.29, and the average pore size was 21.2 °. The BET specific surface area determined by the BET one-point method was 1,780 m ² / g.
150 g of the activated carbon is put in a stainless steel mesh basket, placed on a stainless steel vat containing 150 g of coal-based pitch (softening point: 90 ° C.), and placed in an electric furnace (effective size of the furnace: 300 mm × 300 mm × 300 mm). The composite porous material 2 was obtained by installing and performing a heat treatment. This heat treatment was performed in a nitrogen atmosphere, the temperature was raised to 630 ° C. in 2 hours, and the temperature was maintained at the same temperature for 4 hours. Subsequently, after cooling to 60 ° C. by natural cooling, the composite porous material 2 was taken out of the furnace.
This composite porous material 2 has a mass ratio of the applied carbon material to activated carbon of 38% by mass, a BET specific surface area of 434 m ² / g, a mesopore volume (Vm1) of 0.220 cc / g, and a micropore volume ( Vm2) was 0.149 cc / g. Furthermore, as a result of measuring an average particle diameter using a laser diffraction type particle size distribution analyzer (SALD-2000J) manufactured by Shimadzu Corporation, it was 2.88 μm.
83.4 parts by mass of the composite porous material 2 obtained above, 8.3 parts by mass of acetylene black, 8.3 parts by mass of PVDF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone) were mixed. And a slurry was obtained. The obtained slurry was applied to both sides of an expanded copper foil, dried, and pressed to obtain a negative electrode electrode body having a negative electrode active material layer having a thickness on one side of 30 μm. A lithium metal foil equivalent to 1,500 mAh / g per unit mass of the composite porous material 2 was attached to one surface of the double-sided negative electrode body.

[Assembly and performance of storage element]
Except for using the positive electrode body and the negative electrode body manufactured as described above, a non-aqueous lithium-type power storage element was manufactured in the same manner as in Example 1, and various evaluations were performed.
The evaluation results are shown in Table 2.

<Example 26 and Comparative Examples 7 to 9>
In [Preparation of electrolytic solution], an electrolytic solution was prepared in the same manner as in Example 1, except that the types and amounts of the organic solvent and the electrolyte salt were as described in Table 2, respectively.
Except that this electrolytic solution was used, a non-aqueous lithium-type energy storage device was produced in the same manner as in Example 25, and various evaluations were made.
The evaluation results are shown in Table 2.

<Example 27>
[Preparation of electrolyte solution]
As an organic solvent, a mixed solvent solution of ethylene carbonate (EC): methyl ethyl carbonate (EMC): HFE7000 at a volume ratio of 33: 63: 4 was used, and LiN (SO ₂ F) ₂ and LiPF ₆ were used with respect to the total electrolyte solution. The respective electrolyte salts were dissolved such that the concentration ratio was 75:25 (molar ratio) and the sum of the concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ was 1.2 mol / L. Further, as an additive, a solution obtained by dissolving 1,3-propane sultone (1,3-PS) in an amount of 1% by mass based on the total electrolytic solution was used as a non-aqueous electrolytic solution.
The concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ in the electrolyte solution prepared here were 0.9 mol / L and 0.3 mol / L, respectively.
[Assembly and performance of storage element]
A non-aqueous lithium-type energy storage device was prepared in the same manner as in Example 24 except that the electrolyte solution prepared above was used, and various evaluations were made.
The evaluation results are shown in Table 2.

<Examples 28 to 30>
In [Preparation of electrolyte solution], an electrolyte solution was prepared in the same manner as in Example 27, except that the types and amounts of the organic solvent, the electrolyte salt, and the additives were as described in Table 2, respectively.
Except that this electrolytic solution was used, a non-aqueous lithium-type energy storage device was produced in the same manner as in Example 25, and various evaluations were made.
The evaluation results are shown in Table 2.

  The abbreviations of the organic solvent and the additives in Table 2 have the same meanings as those in Table 1 above.

<Example 31>
[Production of negative electrode body]
100 parts by weight of carbon black (CB1) having an average particle diameter of 30 nm and a BET specific surface area of 254 m ² / g; and 50 parts by weight of an optically isotropic pitch (P1) having a softening point of 110 ° C. and a metaphase amount (QI amount) of 13%. And kneaded in a heating kneader to obtain a kneaded product, which was baked at 1,000 ° C. in a non-oxidizing atmosphere. This was pulverized to an average particle diameter (D50) of 2 μm to obtain a composite carbon material 3. The average particle size of the composite carbon material 3 was measured using MT-3300EX manufactured by Nikkiso Co., Ltd.
Using the pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics, the adsorption isotherm of the composite carbon material 3 was measured using nitrogen as an adsorbate. The BET specific surface area determined by the BET one-point method was 110 m ² / g.
Next, 80.0 parts by mass of the composite carbon material 3 obtained in the above preparation, 8.0 parts by mass of acetylene black, 3.0 parts by mass of CMC (carboxymethylcellulose), 9.0 parts by mass of SBR latex, and distilled water Was mixed to obtain a slurry having a solid content concentration of 18% by mass. Next, the slurry obtained above was applied to both sides of an etched copper foil having a thickness of 15 μm, dried, and pressed to obtain a negative electrode. The thickness of one side of the negative electrode active material layer of the obtained negative electrode was 20 μm. The thickness of the negative electrode active material layer was calculated from the average value of the negative electrode thickness measured at 10 points of the negative electrode using a film thickness meter (Linear Gauge Sensor GS-551) manufactured by Ono Keiki Co., Ltd. Was subtracted to obtain a value. A lithium metal foil equivalent to 1,300 mAh / g per unit mass of the composite porous material 3 was attached to one surface of the double-sided negative electrode body.

[Assembly and performance of storage element]
A non-aqueous lithium-type energy storage device was manufactured in the same manner as in Example 25 except that the negative electrode body manufactured as described above was used, and various evaluations were performed.
The evaluation results are shown in Table 3.

<Example 32 and Comparative Examples 10 to 12>
In [Preparation of electrolyte solution], an electrolyte solution was prepared in the same manner as in Example 1, except that the types and amounts of the organic solvent and the electrolyte salt were as described in Table 3, respectively.
Except that this electrolytic solution was used, a non-aqueous lithium-type energy storage device was produced in the same manner as in Example 31, and various evaluations were made.
The evaluation results are shown in Table 3.

<Example 33>
[Preparation of electrolyte solution]
As an organic solvent, a mixed solvent solution of ethylene carbonate (EC): methyl ethyl carbonate (EMC): HFE7000 at a volume ratio of 33: 63: 4 was used, and LiN (SO ₂ F) ₂ and LiPF ₆ were used with respect to the total electrolyte solution. The respective electrolyte salts were dissolved such that the concentration ratio was 75:25 (molar ratio) and the sum of the concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ was 1.2 mol / L. Further, as an additive, a solution obtained by dissolving 1,3-propane sultone (1,3-PS) in an amount of 1% by mass based on the total electrolytic solution was used as a non-aqueous electrolytic solution.
The concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ in the electrolyte solution prepared here were 0.9 mol / L and 0.3 mol / L, respectively.
[Assembly and performance of storage element]
A non-aqueous lithium-type energy storage device was prepared in the same manner as in Example 31 except that the electrolyte solution prepared above was used, and various evaluations were made.
The evaluation results are shown in Table 3.

<Examples 34 to 36>
In [Preparation of electrolyte solution], an electrolyte solution was prepared in the same manner as in Example 33, except that the types and amounts of the organic solvent and the electrolyte salt were as described in Table 3, respectively.
Except that this electrolytic solution was used, a non-aqueous lithium-type energy storage device was produced in the same manner as in Example 31, and various evaluations were made.
The evaluation results are shown in Table 3.

The abbreviations of the organic solvents and additives in Table 3 have the same meanings as in Table 1 above.
From the above examples, it was verified that the electric storage device according to the present embodiment is a non-aqueous lithium-type electric storage device having high input / output characteristics and little increase in gas generation and internal resistance at high temperatures.

  The non-aqueous lithium-type energy storage device of the present invention is suitable, for example, in the field of a hybrid drive system in which an internal combustion engine, a fuel cell, or a motor in an automobile is combined with an energy storage device; Can be used for

Claims (18)

A negative electrode body, a positive electrode body, an electrode laminate having a separator, and a lithium ion capacitor in which a nonaqueous electrolyte is contained in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent, and the non-aqueous electrolyte is lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ as an electrolyte salt. ) And another electrolyte salt, and the use amount of the lithium bisfluorosulfonylimide is 50 mol parts or more when the total amount of the lithium bisfluorosulfonylimide and the other electrolyte salt is 100 mol parts. A lithium ion capacitor, characterized in that:   The lithium ion capacitor according to claim 1, wherein a volume ratio of the component (c) is 1% to 40% based on a total amount of the organic solvent.   The lithium ion capacitor according to claim 2, wherein the volume ratio of the component (c) is 1% to 7% based on the total amount of the organic solvent. The concentration of LiN (SO ₂ F) _{2 in} the non-aqueous electrolyte is 0.3 mol / L or more and 1.5 mol / L or less based on the total amount of the non-aqueous electrolyte. Item 7. The lithium ion capacitor according to item 1. The other electrolyte salts are LiPF ₆ , LiBF ₄ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₅ ), and LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₄ H), and is selected from these mixed salts, the lithium ion capacitor according to any one of claims 1-4. The other electrolyte salt contains at least one of LiPF ₆ and LiBF _4, lithium ion capacitor according to claim 5. The compound (c) in the non-aqueous electrolyte solution is C ₂ F ₅ OCH ₃ , C ₃ F ₇ OCH ₃ , C ₄ F ₉ OCH ₃ , C ₆ F ₁₃ OCH ₃ , C ₂ F ₅ OC ₂ H ₅ , C _{3 F 7 OC 2 H 5,} C 4 F 9 OC 2 H 5, C 2 F 5 CF (OCH 3) C 3 F 7, CF 3 CH 2 OCF 2 CF 2 H, CHF 2 CF 2 OCH 2 CF 3, From the group consisting of CHF ₂ CF ₂ CH ₂ OCF ₂ CF ₂ H, CF ₃ CF ₂ CH ₂ OCF ₂ CHF ₂ , CF ₃ CH ₂ OCF ₂ CHFCF ₃ , and C ₃ HF ₆ CH (CH ₃ ) OC ₃ HF ₆ The composition according to any one of claims 1 to 6, comprising at least one selected compound, and wherein the volume ratio of these compounds is 0.1% to 50% based on the total amount of the organic solvent. of Chi Umm ion capacitor.   2. The non-aqueous electrolyte further comprises at least one compound selected from the group consisting of sultone compounds, cyclic phosphazenes, fluorinated cyclic carbonates, cyclic carbonates, cyclic carboxylic esters, and cyclic acid anhydrides. The lithium ion capacitor according to any one of claims 1 to 4, wherein The non-aqueous electrolyte,
The following general formula (1):

In the formula, R ^{1 to} R ⁶ represent any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms, and are the same as each other. And n is an integer from 0 to 3. ｝, The following general formula (2):

In the formula, R ^{1 to} R ⁴ represent any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms, and are the same as each other. And n is an integer from 0 to 3. ｝, And the following general formula (3):

In the formula, R ^{1 to} R ⁶ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogenated alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other. Good. 9. The composition according to claim 1, wherein at least one sultone compound selected from the compounds represented by｝ is contained in an amount of 0.1% by mass to 20% by mass based on the total amount of the non-aqueous electrolyte. The lithium ion capacitor according to claim 1. The negative electrode active material is a composite porous material in which the surface of activated carbon is coated with a carbon material, and
The amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method is Vm1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 ° calculated by the MP method is Vm2 (cc / g). ), Satisfying 0.010 ≦ Vm1 ≦ 0.250, 0.001 ≦ Vm2 ≦ 0.200, and 1.5 ≦ Vm1 / Vm2 ≦ 20.0,
The lithium ion capacitor according to claim 1. The negative electrode active material is a composite porous material in which the surface of activated carbon is coated with a carbon material, and
Lithium ion of 1,050 mAh / g or more and 2,050 mAh / g or less per unit mass of the composite porous material is pre-doped;
The mass ratio of the carbon material to the activated carbon is 10% or more and 60% or less, and the thickness of the negative electrode active material layer is 20 μm or more and 45 μm or less per side.
The lithium ion capacitor according to claim 1. The negative electrode active material has the following (i) to (iii):
(I) the negative electrode active material is a composite carbon material containing carbon black and a carbon material,
(Ii) the negative electrode is doped with lithium ions of 1,050 mAh / g or more and 2,500 mAh / g or less per unit mass of the negative electrode active material;
(Iii) the thickness of the negative electrode active material layer is from 10 μm to 60 μm per side,
The lithium ion capacitor according to any one of claims 1 to 9, which satisfies all of the following. Activated carbon contained in the positive electrode active material,
The amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 ° calculated by the MP method is V2 (cc / g). ), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and
Activated carbon having a specific surface area measured by the BET method of not less than 1,500 m ² / g and not more than 3,000 m ² / g.
The lithium ion capacitor according to claim 1. Activated carbon contained in the positive electrode active material,
A mesopore volume V1 (cc / g) derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method satisfies 0.8 <V1 ≦ 2.5,
The micropore volume V2 (cc / g) derived from pores having a diameter of less than 20 ° calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and
Activated carbon having a specific surface area measured by a BET method of not less than 3,000 m ² / g and not more than 4,000 m ² / g.
The lithium ion capacitor according to claim 1. A negative electrode body, a positive electrode body, an electrode laminate having a separator, and a lithium ion capacitor in which a nonaqueous electrolyte is contained in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent;
The non-aqueous electrolytic solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ) and other electrolyte salts as electrolyte salts, and the amount of the lithium bisfluorosulfonylimide used is the lithium bisfluorosulfonylimide. 50 mol parts or more when the total of the imide and the other electrolyte salt is 100 mol parts,
The negative electrode active material is a composite porous material in which the surface of activated carbon is coated with a carbon material, and
The amount of mesopores derived from pores having a diameter of 20 to 500 mm calculated by the BJH method is Vm1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 mm calculated by the MP method is Vm2 (cc / g). ), Satisfying 0.010 ≦ Vm1 ≦ 0.250, 0.001 ≦ Vm2 ≦ 0.200, and 1.5 ≦ Vm1 / Vm2 ≦ 20.0,
Activated carbon contained in the positive electrode active material,
The amount of mesopores derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 ° calculated by the MP method is V2 (cc / g). ), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and
A lithium ion capacitor characterized by being activated carbon having a specific surface area measured by a BET method of not less than 1,500 m ² / g and not more than 3,000 m ² / g. A negative electrode body, a positive electrode body, an electrode laminate having a separator, and a lithium ion capacitor in which a nonaqueous electrolyte is contained in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent;
The non-aqueous electrolytic solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ) and other electrolyte salts as electrolyte salts, and the amount of the lithium bisfluorosulfonylimide used is the lithium bisfluorosulfonylimide. 50 mol parts or more when the total of the imide and the other electrolyte salt is 100 mol parts,
The negative electrode active material is a composite porous material in which the surface of activated carbon is coated with a carbon material, and
Lithium ion of 1,050 mAh / g or more and 2,050 mAh / g or less per unit mass of the composite porous material is pre-doped;
The mass ratio of the carbon material to the activated carbon is 10% or more and 60% or less, and the thickness of the negative electrode active material layer is 20 μm or more and 45 μm or less per side,
Activated carbon contained in the positive electrode active material,
A mesopore volume V1 (cc / g) derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method satisfies 0.8 <V1 ≦ 2.5,
The micropore volume V2 (cc / g) derived from pores having a diameter of less than 20 ° calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and
A lithium ion capacitor characterized by being activated carbon having a specific surface area measured by a BET method of not less than 3,000 m ² / g and not more than 4,000 m ² / g. A negative electrode body, a positive electrode body, an electrode laminate having a separator, and a lithium ion capacitor in which a nonaqueous electrolyte is contained in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent;
The non-aqueous electrolytic solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ) and other electrolyte salts as electrolyte salts, and the amount of the lithium bisfluorosulfonylimide used is the lithium bisfluorosulfonylimide. 50 mol parts or more when the total of the imide and the other electrolyte salt is 100 mol parts,
The negative electrode active material has the following (i) to (iii):
(I) the negative electrode active material is a composite carbon material containing carbon black and a carbonaceous material;
(Ii) the negative electrode is doped with lithium ions of 1,050 mAh / g or more and 2,500 mAh / g or less per unit mass of the negative electrode active material;
(Iii) the thickness of the negative electrode active material layer is from 10 μm to 60 μm per side,
Meet all of
Activated carbon contained in the positive electrode active material,
A mesopore volume V1 (cc / g) derived from pores having a diameter of 20 ° to 500 ° calculated by the BJH method satisfies 0.8 <V1 ≦ 2.5,
The micropore volume V2 (cc / g) derived from pores having a diameter of less than 20 ° calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and
A lithium ion capacitor characterized by being activated carbon having a specific surface area measured by a BET method of not less than 3,000 m ² / g and not more than 4,000 m ² / g. A negative electrode body, a positive electrode body, an electrode laminate having a separator, and a lithium ion capacitor in which a nonaqueous electrolyte is contained in an exterior body,
The negative electrode body has a negative electrode current collector and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector, and the negative electrode active material layer has a carbon material capable of inserting and extracting lithium ions. Containing a negative electrode active material containing the material,
The positive electrode body has a positive electrode current collector and a positive electrode active material layer provided on one surface or both surfaces of the positive electrode current collector, and the positive electrode active material layer contains a positive electrode active material containing activated carbon. Containing, and said non-aqueous electrolyte solution,
(A) at least one selected from ethylene carbonate and propylene carbonate;
(B) at least one selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
(C) The following general formula (c)
R ¹ -OR ² (c)
中 In the formula, R ¹ is a halogen atom or a halogenated alkyl group having 1 to 12 carbon atoms,
R ² is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated alkyl group having 1 to 12 carbon atoms. Containing an organic solvent containing a compound represented by｝,
The volume ratio of the component (b) is 20% or more based on the total amount of the organic solvent;
The non-aqueous electrolytic solution contains lithium bisfluorosulfonylimide (LiN (SO ₂ F) ₂ ) as an electrolyte salt, and the amount of the lithium bisfluorosulfonylimide used is such that the lithium bisfluorosulfonylimide and the other electrolyte are used. When the total amount of the lithium ion capacitor and the salt is 100 mol parts, the internal resistance at 25 ° C. after storage for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C. is Rb. (Ω), the internal resistance at 25 ° C. before storage is Ra (Ω), the internal resistance at −30 ° C. before storage is Rc (Ω), and the capacitance at 25 ° C. before storage is F (F). , The following (a) to (c):
(A) the product Ra · F of Ra and F is 1.9 or less;
(B) Rb / Ra is 1.8 or less; and (c) The amount of gas generated when stored for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C. is 10 × 10 ⁻³ cc / F at 25 ° C. Is the following,
A lithium ion capacitor, characterized by satisfying all of the above at the same time.