JP6262432B2 - Method for manufacturing lithium ion capacitor - Google Patents

Description

  The present invention relates to a method for manufacturing a non-aqueous lithium storage element.

  In recent years, midnight power storage systems, home-use distributed power storage systems based on solar power generation technology, and power storage systems for electric vehicles have attracted attention from the viewpoint of the effective use of energy aimed at preserving the global environment and conserving resources. Yes.

  The first requirement in these power storage systems is that the energy density of the power storage elements used is high. As a promising candidate for a high energy density battery capable of meeting such demands, development of a lithium ion battery has been vigorously advanced.

  The second requirement is high output characteristics. For example, 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) requires high output discharge characteristics in the power storage system during acceleration. ing.

  At present, an electric double layer capacitor using activated carbon as an electrode (hereinafter also simply referred to as “capacitor”) has been developed as a high-power storage element, and has an output characteristic of about 0.5 to 1 kW / l. In addition, these electric double layer capacitors have high durability (cycle characteristics and high temperature storage characteristics) and have been considered to be optimal power storage elements in the field where the high output is required, but the energy density thereof is 1 to 5 Wh. This is only about 1 / l, and the output duration has become a hindrance for practical use.

  On the other hand, nickel-metal hydride batteries currently used in hybrid electric vehicles achieve high output equivalent to electric double layer capacitors and have an energy density of about 160 Wh / l. However, research is underway energetically to further increase the energy density and output, further improve the stability at high temperatures, and enhance the durability.

  In addition, research for higher output is also being conducted in lithium ion batteries. For example, a lithium ion battery has been developed that can obtain a high output exceeding 3 kW / l at a discharge depth (a value representing what percentage of the discharge capacity of the storage element is discharged with reference to full charge) 50%. The energy density is 100 Wh / l or less, and is designed to deliberately suppress the high energy density, which is the greatest feature of lithium ion batteries. Further, its durability (cycle characteristics, high temperature storage characteristics) is inferior to that of an electric double layer capacitor. Therefore, in order to give practical durability, the depth of discharge can be used only in a range narrower than the range of 0 to 100%. For this reason, the capacity that can be actually used is further reduced, and research for further improving the durability is being actively pursued.

  As described above, there is a strong demand for practical use of a power storage device having high output density, high energy density, and durability. However, the existing power storage device described above has advantages and disadvantages. Therefore, a new power storage element that satisfies these technical requirements has been demanded, and development of a power storage element called a lithium ion capacitor has been actively developed as a promising candidate.

  A lithium ion capacitor is a storage element (non-aqueous lithium storage element) that uses a non-aqueous electrolyte containing a lithium salt as an electrolyte, and the positive electrode adsorbs an anion similar to that of an electric double layer capacitor at about 3 V or more at the positive electrode. A storage element that performs charge and discharge by a non-Faraday reaction by desorption and a Faraday reaction by occlusion / release of lithium ions in the negative electrode similar to a lithium ion battery.

  As described above, in an electric double layer capacitor that charges and discharges by a non-Faraday reaction in both the positive electrode and the negative electrode, it has excellent input / output characteristics (that can charge and discharge a large current in a short time) but has a low energy density. On the other hand, a secondary battery that charges and discharges by a Faraday reaction in both the positive electrode and the negative electrode is excellent in energy density but inferior in input / output characteristics. The lithium ion capacitor is a new power storage element that aims to achieve both excellent input / output characteristics and high energy density by performing charge and discharge by a non-Faraday reaction at the positive electrode and a Faraday reaction at the negative electrode.

  As such a lithium ion capacitor, activated carbon is used as the positive electrode active material, and natural graphite or artificial graphite, graphitized mesophase carbon microspheres, graphitized mesophase carbon fiber, graphite whisker, or graphitized carbon fiber is used as the negative electrode active material. Have been proposed (see Patent Document 1). In addition, a power storage element using activated carbon as a positive electrode active material and non-graphitizable carbon or graphite as a negative electrode active material has been proposed (see Patent Documents 2 and 3).

In addition, as a lithium ion capacitor having a small internal resistance, a power storage element using a specific negative electrode material and a specific positive electrode material has been proposed (see Patent Document 4).
The negative electrode material is a composite porous carbon material having a carbonaceous material on the surface of activated carbon, and the amount of mesopores derived from pores having a diameter of 2 nm (20 mm) or more and 50 nm (500 mm) or less calculated by the BJH method is Vm1. (Cc / g), when the amount of micropores derived from pores having a diameter of less than 20 mm calculated by the MP method is Vm2 (cc / g), 0.01 ≦ Vm1 <0.10 and 0.01 ≦ Vm2 < It is made of a carbon material that is 0.30.
The positive electrode material has a mesopore amount derived from pores having a diameter of 2 nm (20 cm) or more and 50 nm (500 cm) or less calculated by the BJH method, V1 (cc / g), and a diameter less than 2 nm (20 cm) calculated by the MP method. When the amount of micropores derived from the pores is V2 (cc / g), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and the specific surface area measured by the BET method is It consists 1500 m ² / g or more 3000 m ² / g or less is activated carbon.

  On the other hand, in order to mount a lithium ion capacitor on an electric vehicle, durability at a high temperature is required, and in particular, a technique for suppressing gas generation that is considered to be derived from decomposition of a non-aqueous electrolyte solution is required. For example, a graphite-based negative electrode material in which the number average particle diameter D50 is controlled to 0.1 to 5 μm and a lithium ion capacitor containing a specific boric acid-based compound in the electrolytic solution have been proposed, and at the time of pre-charging (pre-doping) It is disclosed that there is no gas generation (see Patent Document 5). A solvent containing one or more compounds selected from one or more cyclic carbonate compounds; and an additive containing one or more substances selected from the group consisting of catechol carbonate, fluoroethylene carbonate, propane sultone, and propene sultone; There has also been proposed an electrolytic solution for a lithium ion capacitor that can contain (see Patent Document 6).

Japanese Patent Laid-Open No. 8-1007048 JP-A-9-283383 JP 2008-252013 A International Publication No. 2009/063966 Pamphlet JP 2012-38900 A JP 2012-244171 A

  In the technical field of lithium ion batteries, a film called SEI (Solid Electrolyte Interface) is formed on the surface of the negative electrode by an electrochemical reaction between lithium ions and an electrolytic solution. It is believed that ions can be occluded and released to the negative electrode. Therefore, in the technical field, various additives to be added to the nonaqueous electrolytic solution in order to form good SEI have been proposed.

  In the manufacturing process of a lithium ion capacitor, the point different from the manufacturing process of a normal lithium ion battery is the presence of a step of pre-doping lithium ions into the negative electrode in advance.

  As described in Patent Document 5 described above, an effect of suppressing gas generation during pre-doping is known by previously containing a specific compound in the electrolytic solution. However, there is no description of a technique for suppressing gas generation when stored for a long period of time under high temperature conditions such as in an automobile engine room.

  Further, as described in, for example, Patent Document 6, the present inventors have studied a lithium ion capacitor that has been pre-doped by adding an additive to an electrolytic solution, and as a result, gas may be generated during storage. It was revealed by an accelerated test.

  Therefore, the problem to be solved by the present invention is to provide a non-aqueous lithium storage element having high output characteristics and low gas generation during storage.

As a result of research to solve the above problems, lithium ions are converted into lithium ions in a non-aqueous electrolyte solution containing a non-aqueous solvent that does not contain a reducing compound whose negative electrode reduction potential at 25 ° C. is 1.0 V or more and less than 2.0 V. After doping into the negative electrode of the capacitor, the step of charging and discharging the negative electrode in a non-aqueous electrolyte composed of a non-aqueous solvent containing the reducing compound allows storage while maintaining the high output characteristics of the lithium ion capacitor. The present inventors have found that a non-aqueous lithium storage element that generates less gas at the time can be manufactured.
That is, the present invention is as follows.

[1] One or more negative electrode bodies in which a negative electrode active material layer including a negative electrode active material made of a carbon material capable of occluding and releasing lithium ions is laminated on a negative electrode current collector, and a positive electrode including a positive electrode active material made of activated carbon An electrode laminate formed by laminating one or a plurality of positive electrode bodies in which an active material layer is laminated on a positive electrode current collector, with a separator interposed between the negative electrode body and the positive electrode body; and lithium ions A non-aqueous electrolyte solution containing 0.05% by weight or more and 15% by weight or less of a reducing compound that includes an electrolyte containing a negative electrode having a negative electrode reduction potential of 1.0 V or more and less than 2.0 V at 25 ° C.
Is a method for producing a non-aqueous lithium electricity storage element comprising:
(1) A pre-doping treatment in which lithium ions are occluded in the negative electrode active material in a state in which the negative electrode body or the electrode laminate is immersed in a first nonaqueous electrolytic solution containing less than 0.05% by weight of the reducing compound And (2) the non-aqueous lithium-type electricity storage in a state where the negative electrode body or the electrode laminate is immersed in a second non-aqueous electrolyte solution containing 0.05% to 15% by weight of the reducing compound. An aging process for charging and discharging the device;
Said method.

[2] The first or second non-aqueous electrolyte solution includes the following (a) and (b):
(A) at least one chain carbonate selected from the first group consisting of methyl ethyl carbonate, diethyl carbonate, and dimethyl carbonate, and at least one selected from the second group consisting of ethylene carbonate and propylene carbonate A mixture of seed cyclic carbonates; and (b) propylene carbonate or a mixture of propylene carbonate and ethylene carbonate;
The method for producing a non-aqueous lithium storage element according to [1], which is an electrolytic solution containing 90% by weight or more as a non-aqueous solvent.

[3] The reducing compound is at least one selected from the group consisting of a cyclic carbonate having a double bond, a cyclic sulfite, a sultone, a halogen-substituted cyclic carbonate, a halogen-substituted lactone, and lithium oxalate borate. [1] or [2], the method for producing a non-aqueous lithium storage element.

[4] The non-aqueous lithium storage battery according to any one of [1] to [3], wherein the electrolyte containing lithium ions is LiPF ₆ , LiBF ₄ , or a mixed salt of LiPF ₆ and LiBF _4. Device manufacturing method.

[5] The negative electrode current collector has a through hole, and the negative electrode electrode body is formed by forming the negative electrode active material layer on both surfaces of the negative electrode current collector, and forming a lithium metal foil on the negative electrode. In the case of being obtained by laminating the negative electrode active material layer formed on one side of the current collector,
In the pre-doping process, the negative electrode body or the electrode laminate is applied to the first non-aqueous electrolyte at a temperature of 40 ° C. to 50 ° C. for 10 hours to 72 hours, or at a temperature of less than 40 ° C. The method for producing a non-aqueous lithium storage element according to any one of [1] to [4], which is performed by immersing for 10 hours to 2 weeks.

[6] The negative electrode current collector and the positive electrode current collector have through holes, and the positive electrode active material layer is formed on both surfaces or one surface of the positive electrode current collector, and the negative electrode active material The layer is formed on both sides or one side of the negative electrode current collector, and before the pre-doping process, a lithium metal foil is applied to at least one layer selected from the positive electrode active material layer and the negative electrode active material layer. In the case of stacking the separator between the negative electrode active material layer and the positive electrode active material layer to obtain a pre-doped laminate,
In the pre-doping treatment step, the pre-doped laminate is applied to the first non-aqueous electrolyte solution at a temperature of 40 ° C. to 50 ° C. for 10 hours to 72 hours, or at a temperature of less than 40 ° C. for 10 hours to 2 hours. The method for producing a non-aqueous lithium storage element according to any one of [1] to [4], which is performed by immersing over a week.

[7] The negative electrode active material is a composite porous material in which a carbon material is deposited on the surface of activated carbon, 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), when the amount of micropores derived from pores having a diameter of less than 20 mm calculated by the MP method is Vm2 (cc / g),
0.010 ≦ Vm1 ≦ 0.250,
The method for producing a non-aqueous lithium storage element according to any one of [1] to [6], wherein 0.001 ≦ Vm2 ≦ 0.200 and 1.5 ≦ Vm1 / Vm2 ≦ 20.0 are satisfied.

[8] The positive electrode active material is derived from V1 (cc / g) mesopore amount derived from pores having a diameter of 20 to 500 mm calculated by the BJH method, and pores having a diameter of less than 20 mm calculated by the MP method. When the micropore amount is V2 (cc / g),
It is activated carbon that satisfies 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and has a specific surface area measured by the BET method of 1500 m ² / g to 3000 m ² / g. [1] The method for producing a non-aqueous lithium storage element according to any one of [7].

  ADVANTAGE OF THE INVENTION According to this invention, while providing a high output characteristic to a non-aqueous lithium electrical storage element, gas generation at the time of storage of a non-aqueous lithium electrical storage element can be suppressed.

It is a schematic sectional drawing of the lithium metal foil laminated electrode laminated body in embodiment of this invention. It is a schematic sectional drawing of the lithium metal foil laminated electrode laminated body in another embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

[1. Cathode active material]
Activated carbon can be used as the positive electrode active material.
There are no particular restrictions on the type of activated carbon and its raw materials, but in order to achieve both high capacity (ie high energy density) and high input / output characteristics (ie high power density), the pores of the activated carbon should be optimally controlled. Is preferred. Specifically, 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 amount of micropores derived from pores having a diameter of less than 20 mm calculated by the MP method is calculated. When V2 (cc / g) is satisfied, 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the specific surface area measured by the BET method is 1500 m ² / g or more and 3000 m ^2. Activated carbon that is less than / g is preferred.

  The mesopore amount V1 is preferably a value larger than 0.3 cc / g from the viewpoint of increasing the output characteristics when the positive electrode material is incorporated in the power storage element, and from the viewpoint of suppressing a decrease in the capacity of the power storage element. , Preferably 0.8 cc / g or less. V1 is more preferably 0.35 cc / g or more and 0.7 cc / g or less, and further preferably 0.4 cc / g or more and 0.6 cc / g or less.

  On the other hand, the micropore volume V2 is preferably 0.5 cc / g or more in order to increase the specific surface area of the activated carbon and increase the capacity, and also suppresses the bulk of the activated carbon and increases the density as an electrode. From the viewpoint of increasing the capacity per unit volume, it is preferably 1.0 cc / g or less. V2 is more preferably 0.6 cc / g or more and 1.0 cc / g or less, and further preferably 0.8 cc / g or more and 1.0 cc / g or less.

  Further, the ratio (V1 / V2) of the mesopore amount V1 to the micropore amount 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. From the viewpoint of increasing the ratio of the micropore amount to the mesopore amount to such an extent that the decrease in capacity can be suppressed while obtaining high output characteristics, V1 / V2 is preferably 0.9 or less. A more preferable range of V1 / V2 is 0.4 ≦ V1 / V2 ≦ 0.7, and a more preferable range of V1 / V2 is 0.55 ≦ V1 / V2 ≦ 0.7.

  In the present invention, the micropore volume and mesopore volume of the sample are values determined by the following method. That is, the sample is vacuum-dried at 500 ° C. all day and night, and the adsorption and desorption isotherm is measured using nitrogen as an adsorbate. Using the isotherm on the desorption side at this time, the micropore volume is calculated by the MP method, and the mesopore volume is calculated by the BJH method.

  The MP method uses a “t-plot method” (BC Lippens, JH de Boer, J. Catalysis, 4319 (1965)), and uses a micropore volume, a micropore area, and a micropore. Is a method for obtaining the distribution of M.M. It is a method devised by Mikhail, Brunauer, 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 was proposed by Barrett, Joyner, Halenda et al. (EP Barrett, LG Joyner and P. Halenda, J Amer. Chem. Soc., 73, 373 (1951)).

  In order to maximize the output, the average pore diameter of the activated carbon is preferably 17 mm or more, more preferably 18 mm or more, and most preferably 20 mm or more. Further, in order to maximize the capacity, it is preferably 25 mm or less. The average pore diameter described in the present specification is obtained by dividing the total pore volume per weight obtained by measuring each equilibrium adsorption amount of nitrogen gas at each relative pressure at the liquid nitrogen temperature by the BET specific surface area. Point to what you asked for.

BET specific surface area of the activated carbon is preferably from 1500 m ² / g or more 3000 m ² / g, more preferably not more than 1500 m ² / g or more 2500 m ² / g. When the BET specific surface area is 1500 m ² / g or more, good energy density is easily obtained. On the other hand, when the BET specific surface area is 3000 m ² / g or less, a large amount of binder is used to maintain the strength of the electrode. Since it is not necessary to put in, there exists a tendency for the performance per electrode volume to become high.

The activated carbon having the above-described characteristics can be obtained using, for example, raw materials and processing methods as described below.

  In the embodiment of the present invention, the carbon source used as the raw material for the activated carbon is not particularly limited, and for example, plant raw materials such as wood, wood flour, coconut shell, by-products during pulp production, bagasse, and molasses. Fossil materials such as peat, lignite, lignite, bituminous coal, anthracite, petroleum distillation residue components, petroleum pitch, coke, coal tar; phenol resin, vinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, resorcinol resin, celluloid And various synthetic resins such as 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, plant-based raw materials such as coconut shells and wood flour, and carbides thereof are preferable, and coconut shell carbides are particularly preferable.

  As a method of carbonization and activation for making these raw materials into the activated carbon, known methods such as a fixed bed method, a moving bed method, a fluidized bed method, a slurry method, and a rotary kiln method can be adopted.

  As a carbonization method of these raw materials, nitrogen, carbon dioxide, helium, argon, xenon, neon, carbon monoxide, an exhaust gas such as combustion exhaust gas, or other gases mainly composed of these inert gases. The method of baking for about 30 minutes-about 10 hours at about 400-700 degreeC (preferably 450-600 degreeC) using mixed gas is mentioned.

  As a method for activating the carbide obtained by the carbonization method, a gas activation method in which firing is performed using an activation gas such as water vapor, carbon dioxide, or oxygen is preferably used. Among these, a method using water vapor 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) 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 heating to 800 to 1000 ° C. over a period of time, more preferably 6 to 10 hours.

  Furthermore, prior to the activation treatment of the carbide, the carbide may be activated in advance. In this primary activation, it is usually possible to activate the gas by firing the carbon material at a temperature below 900 ° C. using an activation gas such as water vapor, carbon dioxide or oxygen.

  By appropriately combining the firing temperature and firing time in the carbonization method, the activation gas supply amount, the heating rate and the maximum activation temperature in the activation method, the activated carbon having the above characteristics, which can be used in the embodiment of the present invention. Can be manufactured.

  The average particle size of the activated carbon is preferably 1 to 20 μm. The average particle size described in the present specification is the particle at which the cumulative curve becomes 50% when the cumulative curve is determined with the total volume being 100% when the particle size distribution is measured using a particle size distribution measuring device. Diameter (ie 50% diameter (Median diameter)).

  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 drawback of low durability. On the other hand, when the average particle size is 20 μm or less, it tends to be suitable for high-speed charge / discharge. Furthermore, the average particle diameter is preferably 2 to 15 μm, more preferably 3 to 10 μm.

[2. Negative electrode active material]
The negative electrode active material is a carbon material that can occlude and release lithium ions.

  Examples of the carbon material include non-graphitizable carbon, graphitizable carbon, and composite porous material. More preferably, the negative electrode active material is a composite porous material formed by depositing a carbon material on the surface of activated carbon. In addition to this carbon material, the negative electrode active material layer can also contain materials other than carbon materials that occlude and release lithium ions, such as lithium titanium composite oxides and conductive polymers.

  The negative electrode active material may be used alone or in combination of two or more. The composite porous material can be obtained, for example, by heat-treating activated carbon and a carbon material precursor in the coexistence state.

  The raw material for obtaining the activated carbon used for the raw material of the composite porous material is not particularly limited as long as the obtained composite porous material exhibits desired characteristics, and is petroleum-based, coal-based, plant-based, polymer-based. Commercial products obtained from various raw materials such as can be used. In particular, it is preferable to use activated carbon powder having an average particle size of 1 μm or more and 10 μm or less. The average particle diameter is more preferably 2 μm or more and 6 μm or less. In addition, the measuring method of the said average particle diameter is the same as the measuring method used for the average particle diameter of the activated carbon which is the above-mentioned positive electrode active material.

  On the other hand, the carbon material precursor used as a raw material for the composite porous material is an organic material that can be dissolved in a solid, liquid, or solvent that can be applied to activated carbon by heat treatment. . Examples thereof include synthetic resins such as pitch, mesocarbon microbeads, coke, and phenol resin. Among these carbon material precursors, it is preferable in terms of production cost to use an inexpensive pitch. Pitch is roughly divided into petroleum pitch and coal pitch. Examples of petroleum pitches include crude oil distillation residue, fluid catalytic cracking residue (decant oil, etc.), bottom oil derived from thermal crackers, ethylene tar obtained during naphtha cracking, and the like.

  When the pitch is used, the composite porous material is obtained by depositing a carbon material on the activated carbon by thermally reacting the volatile component or pyrolysis component of the pitch on the surface of the activated carbon. In this case, at a temperature of about 200 to 500 ° C., the deposition of pitch volatile components or pyrolysis components into the activated carbon pores proceeds, and at 400 ° C. or higher, the reaction in which the deposited components become carbon materials proceeds. . The peak temperature during the heat treatment is appropriately determined according to the characteristics of the composite porous material to be obtained, the thermal reaction pattern, the thermal reaction atmosphere, etc., but is preferably 400 ° C. or higher, more preferably 450 ° C. to 1000 ° C. More preferably, the peak temperature is about 500 to 800 ° C. Moreover, the time which maintains the peak temperature at the time of heat processing should just be 30 minutes-10 hours, Preferably they are 1 hour-7 hours, More preferably, they are 2 hours-5 hours. For example, when the heat treatment is performed for 2 hours to 5 hours at a peak temperature of about 500 to 800 ° C., the carbon material deposited on the activated carbon surface is considered to be a polycyclic aromatic hydrocarbon.

  Examples of the method for producing the composite porous material include a method in which activated carbon is heat-treated in an inert atmosphere containing a hydrocarbon gas volatilized from a carbon material precursor, and the carbon material is deposited in a gas phase. In addition, a method in which activated carbon and a carbon material precursor are mixed and heat-treated in advance, 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 is obtained by depositing a carbon material on the surface of activated carbon, but the pore distribution after the carbon material is deposited inside the pores of activated carbon is important. It can be defined by the amount of pores. In the present invention, the ratio of mesopore amount / micropore amount is particularly important as well as the absolute values of 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 mm or more and 500 mm or less calculated by the BJH method in the composite porous material is Vm1 (cc / g), and the diameter of 20 mm calculated by the MP method is used. When the amount of micropores derived from pores less than Vm2 (cc / g) is 0.010 ≦ Vm1 ≦ 0.250, 0.001 ≦ Vm2 ≦ 0.200, and 1.5 ≦ Vm1 / Vm2 ≦ 20.0 is preferred.

  The mesopore amount Vm1 is more preferably 0.010 ≦ Vm1 ≦ 0.225, and further preferably 0.010 ≦ Vm1 ≦ 0.200. About micropore amount Vm2, 0.001 <= Vm2 <= 0.150 is more preferable, and 0.001 <= Vm2 <= 0.100 is still more preferable. The ratio of mesopore amount / micropore amount is more preferably 1.5 ≦ Vm1 / Vm2 ≦ 15.0, and further preferably 1.5 ≦ Vm1 / Vm2 ≦ 10.0. If the mesopore volume Vm1 is less than or equal to the upper limit (Vm1 ≦ 0.250), high charge / discharge efficiency with respect to lithium ions can be maintained, and the mesopore volume Vm1 and the micropore volume Vm2 are equal to or greater than the lower limit (0.010 ≦ Vm1, 0. If 001 ≦ Vm2), high output characteristics can be obtained.

  In addition, in the mesopores with a large pore diameter, the ion conductivity is higher than that of the micropores, so in order to obtain high output characteristics, a mesopore amount of a certain amount or more is necessary, while in the micropores with a small pore size, It is considered that it is necessary to suppress the amount of micropores in order to obtain high durability because impurities such as moisture, which are considered to adversely affect the durability of the storage element, are difficult to desorb. Therefore, it is important to control the ratio between the amount of mesopores and the amount of micropores. When the ratio is equal to or higher than the lower limit (1.5 ≦ Vm1 / Vm2), that is, the carbon material adheres more to the micropores than the mesopores of activated carbon. When the composite porous material after deposition has a large amount of mesopores and a small amount of micropores, high energy density, high output characteristics and high durability (cycle characteristics, float characteristics, etc.) can be obtained. When the ratio between the mesopore amount and the micropore amount is not more than the upper limit (Vm1 / Vm2 ≦ 20.0), high output characteristics can be obtained.

  In the present invention, the method for measuring the mesopore volume Vm1 and the micropore volume Vm2 is the same as that for the positive electrode active material described above.

  In one embodiment of the present invention, as described above, the mesopore / micropore ratio 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 defined in the present invention, the pore distribution of activated carbon used as a raw material is important.

  In the activated carbon used for the raw material of the composite porous material as the negative electrode active material, the mesopore amount derived from the 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 amount of micropores derived from pores less than 20 mm is V2 (cc / g), 0.050 ≦ V1 ≦ 0.500, 0.005 ≦ V2 ≦ 1.000, and 0.2 ≦ V1 / V2 It is preferable that ≦ 20.0.

  About mesopore amount V1, 0.050 <= V1 <= 0.350 is more preferable, and 0.100 <= V1 <= 0.300 is still more preferable. The micropore amount V2 is more preferably 0.005 ≦ V2 ≦ 0.850, and further preferably 0.100 ≦ V2 ≦ 0.800. The ratio of mesopore amount / micropore amount is more preferably 0.22 ≦ V1 / V2 ≦ 15.0, and further preferably 0.25 ≦ V1 / V2 ≦ 10.0. When the mesopore volume V1 of the activated carbon is 0.500 or less and when the micropore volume V2 is 1.000 or less, an appropriate amount is required to obtain the pore structure of the composite porous material of one embodiment of the present invention. Since it is sufficient to deposit a carbon material, the pore structure tends to be easily controlled. On the other hand, when the mesopore amount V1 of the activated carbon is 0.050 or more, when the micropore amount V2 is 0.005 or more, when V1 / V2 is 0.2 or more, and V1 / V2 is 20.0. In the following cases, the pore structure of the composite porous material of one embodiment of the present invention tends to be easily obtained from the pore distribution of the activated carbon.

  The average particle size of the composite porous material in the present invention is preferably 1 μm or more and 10 μm or less. About a lower limit, More preferably, it is 2 micrometers or more, More preferably, it is 2.5 micrometers or more. About an upper limit, More preferably, it is 6 micrometers or less, More preferably, it is 4 micrometers or less. If the average particle size is 1 μm or more and 10 μm or less, good durability is maintained. The measurement method of the average particle diameter of said composite porous material is the same as the measurement method used for the average particle diameter of the activated carbon of the above-mentioned positive electrode active material.

  In the above composite porous material, 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 and 0.15. The following is more preferable. When H / C is 0.35 or less, the structure (typically polycyclic aromatic conjugated structure) of the carbon material deposited on the activated carbon surface is sufficiently developed, so the capacity (energy density) ) And charging / discharging efficiency is high. On the other hand, when H / C is 0.05 or more, since carbonization does not proceed excessively, a sufficient energy density can be obtained. H / C is measured by an elemental analyzer.

In addition, the composite porous material usually has an amorphous structure derived from the activated carbon as a raw material and a crystal structure mainly derived from the deposited carbon material. According to the X-ray wide angle diffraction method, the composite porous material preferably has a structure with low crystallinity in order to exhibit high output characteristics, and has a structure with high crystallinity in order to maintain reversibility in charge and discharge. From the (002) plane spacing d ₀₀₂ is 3.60 to 4.00 mm, and the crystallite size Lc in the c-axis direction obtained from the half width of this peak is 8.0 to 20.0 mm. Some are preferable, d ₀₀₂ is 3.60 to 3.75 Å, and the crystallite size Lc in the c-axis direction obtained from the half width of this peak is 11.0 to 16.0 よ り. preferable.

[3. Non-aqueous electrolyte]
The non-aqueous electrolyte in the production method of the present invention includes a first non-aqueous electrolyte used in the pre-doping process for the negative electrode and a second non-aqueous electrolyte used in the subsequent aging process.

  The first non-aqueous electrolyte contains less than 0.05% by weight of a reducing compound having a negative electrode reduction potential of 1.0 V or more and less than 2.0 V at 25 ° C., and further contains an organic solvent and an electrolyte containing lithium ions (hereinafter, Also referred to as “lithium salt”). Preferably, the first nonaqueous electrolytic solution does not contain the reducing compound.

  The second nonaqueous electrolytic solution contains 0.05% by weight to 15% by weight of a reducing compound having a negative electrode reduction potential at 25 ° C. of 1.0 V or more and less than 2.0 V, and further contains an organic solvent and a lithium salt. Preferably, the content of the reducing compound in the second non-aqueous electrolyte is 0.2 wt% or more and less than 10 wt%.

  If the content of the reducing compound in the non-aqueous electrolyte contained in the non-aqueous lithium storage element is 0.05% by weight or more, the negative electrode active material can be sufficiently covered, and the non-aqueous solvent is decomposed. Can be suppressed. Moreover, if this content is 15% by weight or less, an increase in ion diffusion resistance due to the coating film can be suppressed, and sufficient output characteristics can be obtained, which is preferable.

  The first non-aqueous electrolyte solution and the second non-aqueous electrolyte solution may replace the electrolyte solution in the pre-dope treatment step and the aging treatment step, or the first non-aqueous electrolyte solution used in the pre-dope treatment step. It is good also as a 2nd non-aqueous electrolyte solution used at an aging process process by adding a required amount of the said reducing compound.

[3-1. Reduced compound]
In the present invention, the reduced compound having a negative electrode reduction potential at 25 ° C. of 1.0 V or more and less than 2.0 V is a compound that satisfies the following condition (1).
(1) “The reducing compound is added to a non-aqueous electrolyte obtained by dissolving LiPF ₆ in a solvent obtained by mixing ethylene carbonate and methyl ethyl carbonate at a volume ratio of 1: 2 so as to have a concentration of 1 M / L. When a triode cell having a working electrode made of copper metal and a counter electrode and a reference electrode made of lithium metal was produced, the reductive decomposition potential of the reducing compound at the working electrode was 1. 0V to 2.0V (vsLi / Li ⁺ ). "

  The reductive decomposition potential at 25 ° C. is preferably 1.05 V or more and 1.60 V or less, more preferably 1.10 V or more and 1.50 V or less. If the reductive decomposition potential is 1.0 V or more, it can be reductively decomposed before the cyclic carbonate and the chain carbonate, which are the solvents constituting the nonaqueous electrolyte solution of the nonaqueous lithium storage element. A film in which the reducing compound is decomposed prior to solvent decomposition can be formed. Moreover, if it is 2.0 V or less, a film can be selectively formed in a negative electrode, without this reducing compound being oxidatively decomposed on the positive electrode side.

  The reason why the production method of the present invention is effective is not clear, but the lithium ion is sufficiently pre-doped in the negative electrode by performing the pre-doping process step in a state where a small amount of a film made of a non-aqueous solvent and lithium ion is formed on the negative electrode surface. It is presumed that gas generation due to solvent decomposition is suppressed by sufficiently forming a denser film composed of a reducing compound, a non-aqueous solvent and lithium ions during subsequent charging and discharging.

The reducing compound is not particularly limited as long as it satisfies the above-described negative electrode reduction potential, and examples thereof include the following.
Vinylene carbonate, cyclic carbonates having a double bond represented by vinyl ethylene carbonate, ethylene sulfite, and cyclic sulfites represented by propylene sulfite, 1,3-propane sultone, and 1,4-propane Sultone typified by sultone, halogen-substituted cyclic carbonates typified by chloroethylene carbonate, fluoroethylene carbonate, and trifluoropropylene carbonate, bromogamma-butyrolactone, and halogen-substituted lactones typified by fluorogamma-butyrolactone, and Lithium oxalate borates represented by lithium bis (oxalato) borate and lithium oxalatodifluoroborate.

  Among these, vinylene carbonate, fluoroethylene carbonate, bromogamma-butyrolactone, fluorogamma-butyrolactone, lithium bis (oxalato) borate, and lithium oxalatodifluoroborate are preferred from the viewpoint of excellent reductive decomposability and film forming ability on the negative electrode.

  Moreover, the reducing compound for negative electrode films may be 1 type, and may mix 2 or more types.

[3-2. Organic solvent]
As the organic solvent, the following (a) and (b): from the viewpoint that a non-aqueous electrolytic solution having both high dielectric constant and low viscosity can be obtained.
(A) at least one chain carbonate selected from the first group consisting of methyl ethyl carbonate, diethyl carbonate, and dimethyl carbonate, and at least one selected from the second group consisting of ethylene carbonate and propylene carbonate A non-aqueous solvent mixed with a seed cyclic carbonate; and (b) a non-aqueous solvent mixed with propylene carbonate alone or with propylene carbonate and ethylene carbonate;
Those containing at least one of these are preferred. From the same viewpoint, the content of the organic solvent (a) and / or (2) in the first or second non-aqueous electrolyte is preferably 90% by weight or more.

[3-3. Electrolyte containing lithium ion]
The electrolyte dissolved in these organic solvents is a lithium salt. Examples of preferred lithium salts include LiBF ₄ , LiPF ₆ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₅ ), LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₄ H) and mixed salts thereof. Among these, LiPF ₆ , LiBF ₄ , or a mixed salt of LiPF ₆ and LiBF ₄ is preferable.

  The electrolyte concentration in the non-aqueous electrolyte is preferably in the range of 0.5 to 2.0 mol / L. If it is less than 0.5 mol / L, anions are insufficient and the capacity of the electricity storage element tends to be low. On the other hand, if it exceeds 2.0 mol / L, undissolved lithium salt precipitates in the electrolyte solution, or the viscosity of the electrolyte solution becomes too high. There is a tendency to decrease.

[4. Other components]
In an embodiment of the present invention, the nonaqueous lithium-type energy storage device includes a current collector, a component other than the active material in the active material layer, an electrode body, and a separator in addition to the above-described electrolyte solution, positive electrode active material, and negative electrode active material. Including exterior bodies. Hereinafter, these components will be described.

(4-1. Current collector)
A current collector (collectively referred to as a positive electrode current collector and a negative electrode current collector) is usually a metal foil that does not undergo degradation such as elution and reaction in a power storage element. There is no restriction | limiting in particular as this metal foil, For example, copper foil, aluminum foil, etc. are mentioned. In the electricity storage device of the present invention, the positive electrode current collector is preferably an aluminum foil and the negative electrode current collector is preferably a copper foil.

  Further, the current collector may be a normal metal foil having no through hole or a metal foil having a through hole. In order to facilitate the pre-doping process of lithium to the negative electrode described later, a metal foil having a through hole is preferable. Both the positive electrode current collector and the negative electrode current collector may be a metal foil having a through hole, and the negative electrode current collector is a metal foil having a through hole, and the positive electrode current collector is a metal having no through hole. It may be a foil.

  The thickness of the current collector is preferably 1 to 100 μm. A thickness of the current collector of 1 μm or more is preferable because the shape and strength of the positive electrode body and the negative electrode body formed by fixing the active material layer to the current collector can be maintained. On the other hand, it is preferable that the current collector has a thickness of 100 μm or less because the weight and volume of the electricity storage element are appropriate and the performance per weight and volume tends to be high.

(4-2. Components other than the active material in the active material layer)
For the active material layer (collectively referred to as the positive electrode active material layer and the negative electrode active material layer), known components contained in the active material layer in known lithium ion batteries, capacitors, and the like can be used. In addition to the above-described positive electrode active material or negative electrode active material, the active material layer can contain known components such as a binder, a conductive filler, a thickener, and the like, and the type thereof is not particularly limited. Hereinafter, the details of the components of the active material layer in the non-aqueous lithium storage element will be described.

  The active material layer can contain a conductive filler, such as carbon black, if necessary. 0-30 mass parts is preferable with respect to 100 mass parts of active materials, and, as for the usage-amount of an electroconductive filler, 1-20 mass parts is more preferable. The conductive filler is preferably used from the viewpoint of high power density, but when the amount used is 30 parts by mass or less, the proportion of the amount of the active material in the active material layer is high, and the output per volume is high. This is preferable because the density tends to increase.

  In order to fix the above-mentioned active material and further the conductive filler used as necessary on the current collector as an active material layer, as a binder, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluorine Rubber, 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 and more preferably in the range of 5 to 15 parts by mass with respect to 100 parts by mass of the active material. When the amount of the binder used is 20 parts by mass or less, since the binder does not completely cover the surface of the active material, ions enter and exit faster, and high power density tends to be obtained, which is preferable. On the other hand, when the amount of the binder used is 3 parts by mass or more, it is preferable because the active material layer tends to adhere to the current collector as an active material layer in which the active material particles are bonded to each other.

(4-3. Electrode body)
In the present invention, the electrode body (collectively referred to as the positive electrode body and the negative electrode body) is formed by forming the active material layer only on the upper surface (one surface) of the current collector, or formed on the upper and lower surfaces (both surfaces). Say.

  The electrode body is formed by fixing an active material layer to a current collector. In the electrode body, the thickness of the active material layer is usually preferably about 30 to 200 μm. It is preferable that the thickness of the active material layer be 30 μm or more because the ratio of the amount of active material to the entire power storage element increases and the energy density tends to increase. On the other hand, it is preferable that the thickness of the active material layer is 200 μm or less because the resistance inside the electrode is reduced and the output density tends to increase.

  The electrode body can be manufactured by an electrode manufacturing technique such as a known lithium ion battery or an electric double layer capacitor. For example, a material containing an active material, a binder, and a conductive filler is mixed with water or an organic solvent to form a slurry, and the slurry is applied onto a current collector, dried, and pressed as necessary to obtain an active material. Obtained by forming a layer. In addition, without using a solvent, a material containing an active material, a binder, and a conductive filler can be dry-mixed and press-molded, and then attached to a current collector using a conductive adhesive.

  In order to attach an electrode tab to be described later, it is preferable to provide a region (hereinafter also referred to as “uncoated region”) where the active material layer is not applied (attached) to a part of the current collector. In addition, after apply | coating to the whole area | region, you may provide an uncoated area | region by removing the active material layer of one part area | region.

(4-4. Separator)
As the separator, a polyethylene microporous film used for a lithium ion secondary battery, a polypropylene microporous film, a cellulose nonwoven paper used for an electric double layer capacitor, or the like can be used.

  The thickness of the separator is preferably 10 μm or more and 50 μm or less. A thickness of 10 μm or more is preferable because self-discharge due to internal micro-shorts tends to be small. On the other hand, a thickness of 50 μm or less is preferable because the output characteristics of the storage element tend to be high.

(4-5. Electrode terminal / electrode tab)
In the case of a stacked type storage element, the electrode body and the separator are shaped into a sheet shape that matches the shape of the storage element, and one end of the positive electrode terminal and the negative electrode current collector are not applied to the uncoated area of the positive electrode current collector. One end of the negative electrode terminal is electrically connected to the region. Of course, the electrode terminal (collectively referred to as the positive electrode terminal and the negative electrode terminal) and an uncoated region of the current collector may be connected via another metal component.

  The material of the positive terminal is preferably aluminum, and the material of the negative terminal is preferably nickel-plated copper. The electrode terminal generally has a substantially quadrilateral shape, one end of which is electrically connected to the current collector region of the electrode, and the other end is connected to an external load (in the case of discharging) or a power source (charging). Electrically connected).

  For example, an ultrasonic welding method is generally used as an electrical connection method between the electrode body and the electrode terminal described above, but resistance welding, laser welding, joining by solder or silver brazing may be used, and there is no particular limitation.

  In the case of a winding type power storage element, the electrode body and the separator are shaped into a long sheet, and one end of the positive electrode tab is formed in the uncoated area of the positive electrode current collector, and the negative electrode tab is formed in the uncoated area of the negative electrode current collector. Electrically connect one end of the.

(4-6. Electrode laminate)
When the positive electrode body and the negative electrode body are sheet-like, the positive electrode body and the negative electrode body are laminated via a sheet-like separator to form an electrode laminate. In addition, when the positive electrode body and the negative electrode body are long, they are wound and laminated through a long separator to form an electrode laminate.

  Further, for lithium ion pre-doping, a lithium metal foil laminated electrode body may be formed by laminating a lithium metal foil on the above electrode laminate.

  An example of a lithium metal foil laminated electrode body in the case where the negative electrode current collector is a metal foil having a through hole and the positive electrode current collector is a metal foil having no through hole is shown in FIG. In this case, one lithium metal foil (3c) is required for each negative electrode body (3A), but this has the advantage that the time required for the pre-doping treatment is short and the uniformity is improved.

  FIG. 2 shows an example of a lithium metal foil laminated electrode body when both the positive electrode current collector and the negative electrode current collector are metal foils having through holes. This case has an advantage that the negative electrode active material layers (3b) of the plurality of negative electrode bodies (3B) can be simultaneously pre-doped with one or two lithium metal foils (7). The number and thickness of the lithium metal foil (7) may be determined according to the amount of the negative electrode active material and the required amount of pre-doping.

(4-7. Exterior body)
The electrode laminate is inserted into the exterior body together with the non-aqueous electrolyte.
A metal can, a laminate film, or the like can be used as the exterior body. The metal can is preferably made of aluminum. In this case, for example, the metal can is used as a negative electrode terminal, and a metal lid caulked on the metal can with an insulator interposed therebetween is used as a positive electrode terminal. The electrode body and the terminal (collectively referred to as the positive electrode terminal and the negative electrode terminal) are electrically connected by the electrode tab (collectively referred to as the positive electrode tab and the negative electrode tab).

  Moreover, as this laminate film, the film which laminated | stacked metal foil and the resin film is preferable, and the thing of the 3 layer structure which consists of an outer layer resin film / metal foil / interior resin film is illustrated. The outer layer 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 the 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 electrolyte contained therein and melts and seals it at the time of heat sealing. Polyolefin, acid-modified polyolefin, and the like can be suitably used.

  When using a laminate film exterior body, the periphery of the laminate film is sealed in a state where the end of the electrode terminal is drawn out to the external space of the exterior body. The sealing method is preferably heat sealing.

[5. Manufacturing process]
The manufacturing method of the non-aqueous lithium storage element of this embodiment is characterized by a pre-doping process and an aging process. That is, after the lithium ion is pre-doped in the negative electrode active material of the negative electrode body in the first non-aqueous electrolyte, the surface of the negative electrode is charged and discharged in the second non-aqueous electrolyte and subjected to an aging treatment. It is a manufacturing method of the nonaqueous lithium electrical storage element in which a film is formed.

(Lithium ion pre-doping process)
The negative electrode body is pre-doped with lithium ions in advance. As a pre-doping method, a known method, for example, a negative electrode body is assembled in a state where a lithium metal foil is laminated on a negative electrode active material layer to form a lithium metal foil laminated electrode body, which is used as a first non-aqueous electrolyte solution. You can use the putting method. By pre-doping with lithium ions, the capacity and operating voltage of the power storage element can be controlled.

  As conditions for the pre-doping treatment, the temperature is preferably from room temperature to 50 ° C. By setting the temperature to room temperature or higher, the pre-doping time can be as short as possible. Moreover, by setting it as 50 degrees C or less, the load to an electrode can be reduced and deterioration can be suppressed.

  The pre-doping time is preferably 10 hours or more and 2 weeks or less when the pre-doping temperature is less than 40 ° C., preferably 10 hours or more and 72 hours or less when the pre-doping temperature is 40 ° C. or more, and 15 hours or more. 48 hours or less is more preferable. When the temperature is lower than 40 ° C., the shortage of the lithium ion pre-doping amount can be avoided by setting the time to 10 hours or longer, and the load on the electrode can be reduced and the deterioration can be suppressed by setting the time to 2 weeks or shorter. Further, in the case of 40 ° C. or higher, the upper limit of time is preferably 72 hours or shorter in order to reduce the load on the electrode and suppress deterioration.

  For example, as shown in FIG. 1, using a negative electrode current collector having a through hole, a negative electrode active material layer is formed on both sides of the negative electrode current collector, and a lithium metal foil is formed on one side of the negative electrode current collector. When the negative electrode body is obtained by laminating the negative electrode active material layer formed on the negative electrode active material layer, the pre-doping treatment step is performed by applying the negative electrode body or the electrode stack body to the first non-aqueous electrolyte solution at 40 ° C. to 50 ° C. It is preferably performed by dipping at a temperature of 10 ° C. for 10 hours to 72 hours, or at a temperature of less than 40 ° C. for 10 hours to 2 weeks.

  For example, as shown in FIG. 2, a positive electrode active material layer is formed on both surfaces or one surface of a positive electrode current collector using a negative electrode current collector and a positive electrode current collector both having through-holes. A negative electrode active material layer is formed on both sides or one side, and a lithium metal foil is opposed to at least one layer selected from the positive electrode active material layer and the negative electrode active material layer before the pre-doping treatment step, and the negative electrode active material layer When a separator is laminated between the positive electrode active material layer and a pre-doped stacked body to obtain a pre-doped stacked body, the pre-doping treatment step is performed by applying the pre-doped stacked body to the first non-aqueous electrolyte at 40 ° C. to 50 ° C. It is preferably carried out by dipping at a temperature for 10 hours to 72 hours or at a temperature of less than 40 ° C. for 10 hours to 2 weeks.

(Sealing process for exterior body)
After the lithium ion pre-doping treatment step, the first non-aqueous electrolyte is replaced with the second non-aqueous electrolyte to seal the outer package. Alternatively, the exterior body may be sealed as an electrolyte that satisfies the conditions of the second non-aqueous electrolyte by adding the above-described reducing compound to the first non-aqueous electrolyte.

  By eliminating the above-mentioned reducing compound during the lithium ion pre-doping treatment step, unnecessary side reactions due to the lithium ion and the reducing compound can be suppressed, and in the subsequent aging treatment step, the reducing compound originates on the outermost surface of the negative electrode. Therefore, it is considered that decomposition of the electrolyte solvent can be efficiently suppressed and gas generation can be suppressed.

(Aging process)
The purpose of the aging treatment step is to complete the device mainly in a state where a film on the surface of the negative electrode is formed and optimum charge / discharge efficiency can be exhibited. Specifically, an aging process step is established by repeating charging and discharging under specific conditions an appropriate number of times before use.

  In this embodiment, it is preferable to repeat charging and discharging an appropriate number of times with a current value of 0.1 to 10C. 0.5-2C is more preferable, and 1C is most preferable. If it is 0.1 C or more, the time required for the aging treatment is shortened, and if it is 10 C or less, it is considered that a coating film is sufficiently formed.

  First, when the upper limit value of the operating voltage range of the storage element is Emax (V) and the lower limit value is Emin (V), the state of charge (SOC) when the voltage is E (V) is {(E−Emin). / (Emax−Emin)} × 100 (%). The working voltage of the lithium ion capacitor mainly varies depending on the type of the negative electrode material, and typical manufacturer recommended values are an upper limit of 3.8 to 4.0 V and a lower limit of about 2.0 to 2.2 V. Therefore, taking a common range, assuming that the upper limit value Emax of the working voltage range of the lithium ion capacitor is 3.8 V and the lower limit value Emin is 2.2 V, an arbitrary value E between 2.2 and 3.8 V is assumed. The state of charge SOC (%) when (V) is represented by {(E-2.2) / (3.8-2.2)} × 100.

  Next, preferable conditions for the aging treatment step are shown.

  The charging step is to charge SOC = 85 to 130% at a constant current and constant voltage with a current value of 1C, and preferably SOC = 100 to 125%. The charging time is preferably a constant voltage charging time of 1 hour to 2 hours. Furthermore, the environment to charge is 20-85 degreeC, Preferably it is 25-60 degreeC.

  The discharging step is to discharge SOC = -12.5% to 20% at a constant current at a current value of 1C, and preferably SOC = 0 to 15%. Moreover, the environment to discharge is 20-85 degreeC, Preferably it is 25-60 degreeC.

  When one cycle is defined as one charge and one discharge (or vice versa), the number of cycles is preferably 20 to 400 cycles, more preferably 50 to 200 cycles. By setting it to 20 cycles or more, insufficient formation of SEI can be avoided, and by setting it to 400 cycles or less, the load on the electrode can be reduced and deterioration can be suppressed.

  In the aging treatment step, it is preferable to perform a step of removing the generated gas as necessary. This is because the gas generated by the aging process becomes a resistance component of the power storage element and deteriorates the characteristics. This gas is thought to be generated by the decomposition of moisture adsorbed by the solvent or material by an electrochemical reaction. Note that the step of degassing is performed by opening a part of the sealed outer package and sealing again.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<Example 1>
[Preparation of positive electrode active material / positive electrode body]
The crushed palm shell carbide was carbonized in nitrogen in a small carbonization furnace at 500 ° C. for 3 hours. The treated carbide is placed in an activation furnace, 1 kg / h of steam is heated in a preheating furnace, and the temperature is raised to 900 ° C. over 8 hours. To obtain activated carbon. The obtained activated carbon was washed with water for 10 hours and then drained. Then, after drying for 10 hours in an electric dryer maintained at 115 ° C., pulverization was performed for 1 hour with a ball mill to obtain activated carbon 1.

It was 4.2 micrometers as a result of measuring the average particle diameter of the activated carbon 1 using the Shimadzu Corporation laser diffraction type particle size distribution analyzer (SALD-2000J). Further, the pore distribution was measured with a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics Co., Ltd. using nitrogen as an adsorbate. The specific surface area was determined by the BET single point method. Further, using the desorption side isotherm, the mesopore amount was determined by the BJH method, and the micropore amount was determined by the MP method. As a result of measuring the pore distribution of the activated carbon 1, the BET specific surface area was 2360 m ² / g, the mesopore volume (V1) was 0.52 cc / g, and the micropore volume (V2) was 0.88 cc / g.

  80.8 parts by mass of 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-methylpyrrolidone) Mixing to obtain a slurry. Next, the obtained slurry was 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 positive electrode active material layer thickness of 55 μm. .

[Preparation of negative electrode active material / negative electrode body]
With respect to commercially available coconut shell activated carbon, the pore distribution was measured using nitrogen as an adsorbate with a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics. The specific surface area was determined by the BET single point method. Further, as described above, using the isotherm on the desorption side, the mesopore amount was determined by the BJH method, and the micropore amount was determined by the MP method. As a result, the BET specific surface area was 1,780 m ² / g, the mesopore volume was 0.198 cc / g, the micropore volume was 0.695 cc / g, V1 / V2 = 0.29, and the average pore diameter was 21.2 mm. there were.

150 g of this coconut shell activated carbon is placed in a stainless steel mesh basket, placed on a stainless steel bat containing 270 g of a coal-based pitch (softening point: 50 ° C.), and an electric furnace (effective size in the furnace 300 mm × 300 mm × 300 mm) It installed in and performed the heat reaction. Heat treatment is performed in a nitrogen atmosphere by raising the temperature to 600 ° C. in 8 hours and holding at that temperature for 4 hours. Subsequently, after cooling to 60 ° C. by natural cooling, the composite porous material that is taken out from the furnace and becomes a negative electrode material The material 1 was obtained. 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 0.00. 0843 cc / g and 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) are mixed to prepare a slurry. Obtained. Next, 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 thickness of 60 μm.

  A lithium metal foil corresponding to 760 mAh / g per unit weight of the composite porous material 1 was attached to one side of the double-sided negative electrode body.

[Preparation of first non-aqueous electrolyte]
A solution obtained by dissolving LiPF ₆ to a concentration of 1 mol / l in a non-aqueous solvent in which ethylene carbonate (EC) and methyl ethyl carbonate (MEC) are in a volume ratio of 1: 2 is a first non-aqueous system. Used as electrolyte.

[Assembly and performance of storage element]
The obtained electrode body is cut into 100 mm × 100 mm, the single-sided positive electrode body is used for the top and bottom surfaces, and 18 double-sided negative electrode bodies and 17 double-sided positive electrode bodies are placed between the top and bottom surfaces. In addition, after laminating 36 non-woven cellulose separators between the negative electrode body and the positive electrode body, electrode terminals were connected to the negative electrode body and the positive electrode body to obtain an electrode laminate. This laminated body was inserted into an outer package made of a laminate film, 100 g of the first non-aqueous electrolyte solution was injected, the outer package was sealed, and a non-aqueous lithium storage element was assembled.

  The non-aqueous lithium storage element was stored in a 45 ° C. environment for 24 hours, so that lithium ions were pre-doped on the negative electrode. Subsequently, the cell was once opened, and 2.0 parts by weight of vinylene carbonate as a reducing compound in a ratio with respect to 100 parts by weight of the first electrolyte was added to obtain a second non-aqueous electrolyte, and then the outer package was sealed. .

  As an aging process of the storage element, in a 25 ° C. environment, a constant current charge to 4.0 V is performed at a current value of 1 C, and then a 4.0 V constant voltage charge is performed for 1 hour, and then a current value of 1 C is increased to 2.0 V. A constant current discharge was performed. This was performed for 60 cycles, and the exterior body was once opened, degassed, and sealed again to complete the electricity storage device.

  The produced power storage device was evaluated in a 25 ° C. environment.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 67.5%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, when the amount of gas generated after storage was measured by the Archimedes method, it was 2.5 cc.

<Example 2>
A power storage element similar to that of Example 1 was prepared except that 1.5 parts by weight of propylene sulfite as a reducing compound in a ratio with respect to the first nonaqueous electrolytic solution was added.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 66.3%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method, and it was 2.8 cc.

<Example 3>
A power storage device similar to that of Example 1 was prepared except that 2.0 parts by weight of fluoroethylene carbonate as a reducing compound in a ratio with respect to the first nonaqueous electrolytic solution was added.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 68.1%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method, and it was 2.7 cc.

<Example 4>
A power storage device similar to that of Example 1 was prepared except that 0.3 part by weight of lithium bis (oxalato) borate as a reducing compound was added in a ratio with respect to the first nonaqueous electrolytic solution.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 67.1%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method and found to be 3.1 cc.

<Example 5>
A solution obtained by dissolving 1 mol / l concentration of LiPF ₆ and 0.1 mol / l concentration of LiBF ₄ in a non-aqueous solvent of ethylene carbonate (EC) and methyl ethyl carbonate (MEC) in a volume ratio of 1: 2. Was prepared as a first non-aqueous electrolyte solution, and a storage element similar to that of Example 1 was prepared except that 2.5 parts by weight of vinylene carbonate as a reducing compound was added in a ratio to the first non-aqueous electrolyte solution. did.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 66.5%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method and found to be 2.6 cc.

<Example 6>
A solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a non-aqueous solvent of propylene carbonate (PC) and methyl ethyl carbonate (MEC) in a volume ratio of 1: 2 is used as the first non-aqueous electrolyte. A power storage element similar to that in Example 1 was prepared except that.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 63.1%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, when the amount of gas generated after storage was measured by the Archimedes method, it was 1.4 cc.

<Example 7>
A power storage device similar to that of Example 1 was prepared except that vinylene carbonate as a reducing compound was added in an amount of 10 parts by weight relative to the first nonaqueous electrolytic solution.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 61.5%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method, and it was 0.9 cc.

<Example 8>
[Preparation of positive electrode active material / positive electrode body]
It was produced in the same manner as in Example 1.

[Preparation of negative electrode active material / negative electrode body]
After oxidizing the coal-based pitch at 250 ° C. for about 2 hours in an air atmosphere,
Heat treatment was performed at 0 ° C. for 1 hour. The obtained material was pulverized for about 4 hours by a ball mill pulverizer to obtain a non-graphitizable carbon material 1 serving as a negative electrode material. Evaluation of physical properties of the non-graphitizable carbon material 1 was performed in the same manner as in Example 1. BET specific surface area is 4.1 m ² / g, mesopore volume (V
m1) is 0.0081 cc / g, micropore volume (Vm2) is 0.0012 cc / g, Vm
It was 1 / Vm2 = 6.75.

83.4 parts by mass of the non-graphitizable carbon material 1, 8.3 parts by mass of acetylene black, 8.3 parts by mass of PVDF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone) are mixed, A slurry was obtained. Next, the obtained slurry was applied to both sides of the expanded copper foil, dried and pressed to obtain a negative electrode body having an active material layer thickness of 60 μm.

  A lithium metal foil corresponding to 400 mAh / g per unit weight of the non-graphitizable carbon material 1 was attached to one side of the double-sided negative electrode body.

[Preparation of first non-aqueous electrolyte]
It was produced in the same manner as in Example 1.

[Assembly and performance of storage element]
It was produced in the same manner as in Example 1.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 63.7%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method and found to be 2.0 cc.

<Comparative Example 1>
A storage element similar to that of Example 1 was prepared without using the reducing compound, and with the first non-aqueous electrolyte.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 70.8%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, when the amount of gas generated after storage was measured by the Archimedes method, it was 10 cc.

<Comparative example 2>
[Preparation of positive electrode active material / positive electrode body]
It was produced in the same manner as in Example 1.

[Preparation of negative electrode active material / negative electrode body]
It was produced in the same manner as in Example 1.

[Preparation of non-aqueous electrolyte]
In a non-aqueous solvent in which ethylene carbonate (EC) and methyl ethyl carbonate (MEC) are in a volume ratio of 1: 2, 2.0 parts by weight of vinylene carbonate (VC) with respect to 1 mol / l concentration of LiPF ₆ and the electrolytic solution. The solution obtained by dissolution was used as a non-aqueous electrolyte.

[Assembly and performance of storage element]
The obtained electrode body is cut into 100 mm × 100 mm, the single-sided positive electrode body is used for the top and bottom surfaces, and 18 double-sided negative electrode bodies and 17 double-sided positive electrode bodies are placed between the top and bottom surfaces. In addition, after laminating 36 non-woven cellulose separators between the negative electrode body and the positive electrode body, electrode terminals were connected to the negative electrode body and the positive electrode body to form an electrode laminate. This laminated body was inserted into an outer package made of a laminate film, 100 g of the non-aqueous electrolyte solution was injected to seal the outer package, and a non-aqueous lithium storage element was assembled.

  The non-aqueous lithium storage element was stored in a 45 ° C. environment for 24 hours to dope lithium ions into the negative electrode. Next, as an aging process of the storage element, in a 25 ° C. environment, a constant current charge is performed up to 4.0 V with a current value of 1 C, and then a 4.0 V constant voltage charge is performed for 1 hour. A constant current discharge was performed up to 0.0V. This was performed for 60 cycles, opened and degassed, and the exterior body was sealed again to complete the electricity storage device.

  The produced power storage device was evaluated in a 25 ° C. environment.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 61.3%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, when the amount of gas generated after storage was measured by the Archimedes method, it was 8.8 cc.

<Comparative Example 3>
A power storage element similar to that in Example 1 was prepared except that 18 parts by weight of vinylene carbonate as a reducing compound was added in a proportion relative to the first nonaqueous electrolytic solution.

[Measurement of output characteristics and stored gas]
The produced power storage element was charged to 4.0 V with a current of 1 C, and thereafter, constant current and constant voltage charging in which a constant voltage of 4.0 V was applied was performed for 2 hours. Subsequently, by discharging to 2.0 V with a constant current of 1 C, an output capacity of 1 C was obtained. Next, the same charge was performed and the battery was discharged to 2.0 V at a current value of 300 C, whereby an output capacity of 300 C was obtained. That is, the ratio of the discharge capacity at 300 C to the discharge capacity at 1 C was 48.9%.

  Moreover, after charging to 4.0V by 1C and performing constant current constant voltage charge which applies a constant voltage of 4.0V for 2 hours after that, it preserve | saved for one month in a 60 degreeC thermostat. Next, the amount of gas generated after storage was measured by the Archimedes method, and it was 1.7 cc.

  The above results are summarized in Table 1 below.

  From the results shown in Table 1, it is possible to provide a non-aqueous lithium storage element having both high output characteristics and excellent high temperature durability with less gas generation by the production method of the present invention.

  The power storage device of the present invention can be suitably used in automobiles, in the field of hybrid drive systems in which an internal combustion engine or a fuel cell, a motor, and a power storage device are combined, and for assisting instantaneous power peaks.

DESCRIPTION OF SYMBOLS 1 Lithium metal foil laminated electrode laminated body 2A Positive electrode body 2B Positive electrode body 2C Positive electrode body 2a Positive electrode collector (no through-hole)
2b Cathode active material layer 2c Cathode active material layer 2d Cathode current collector (with through hole)
3A Negative electrode body 3B Negative electrode body 3a Negative electrode current collector (with through hole)
3b Negative electrode active material layer 3c Lithium metal foil 4 Separator 5 Lithium metal foil laminated electrode laminate 6 Carrier 7 Lithium metal foil

Claims (8)

A negative electrode active material layer including a negative electrode active material layer including a negative electrode active material made of a carbon material capable of occluding and releasing lithium ions, and a positive electrode active material layer including a positive electrode active material made of activated carbon. An electrode laminate formed by laminating one or a plurality of positive electrode bodies stacked on a positive electrode current collector with a separator interposed between the negative electrode body and the positive electrode body; and containing lithium ions A non-aqueous electrolyte solution containing 0.05% by weight to 15% by weight of a reducing compound containing an electrolyte and having a negative electrode reduction potential at 25 ° C. of 1.0 V or more and less than 2.0 V;
Is a method for producing a lithium ion capacitor, which is housed in an exterior body, the method comprising the following steps:
(1) a pre-dope treatment step of occluding lithium ions in the negative electrode active material in a state where the negative electrode body or the electrode laminate is immersed in a first non-aqueous electrolyte solution not containing the reducing compound; and (2) An aging treatment step of charging and discharging a lithium ion capacitor in a state where the negative electrode body or the electrode laminate is immersed in a second non-aqueous electrolyte solution containing 0.05% by weight or more and 15% by weight or less of the reducing compound;
The method according to the order described. Said 1st or 2nd non-aqueous electrolyte solution is the following (a) and (b):
(A) at least one chain carbonate selected from the first group consisting of methyl ethyl carbonate, diethyl carbonate, and dimethyl carbonate, and at least one selected from the second group consisting of ethylene carbonate and propylene carbonate A mixture of seed cyclic carbonates; and (b) propylene carbonate or a mixture of propylene carbonate and ethylene carbonate;
The method for producing a lithium ion capacitor according to claim 1, wherein the electrolytic solution contains 90% by weight or more as a non-aqueous solvent.   The reduced compound is at least one selected from the group consisting of a cyclic carbonate having a double bond, a cyclic sulfite, a sultone, a halogen-substituted cyclic carbonate, a halogen-substituted lactone, and lithium oxalate borate. 3. A method for producing a lithium ion capacitor according to 2. The method for producing a lithium ion capacitor according to claim 1, wherein the electrolyte containing lithium ions is LiPF ₆ , LiBF ₄ , or a mixed salt of LiPF ₆ and LiBF ₄ . The negative electrode current collector has a through hole, and the negative electrode electrode body has the negative electrode active material layer formed on both surfaces of the negative electrode current collector, and the lithium metal foil is formed on the negative electrode current collector. In the case of being obtained by laminating on the negative electrode active material layer formed on one side of
In the pre-doping process, the negative electrode body or the electrode laminate is applied to the first non-aqueous electrolyte at a temperature of 40 ° C. to 50 ° C. for 10 hours to 72 hours, or at a temperature of less than 40 ° C. The manufacturing method of the lithium ion capacitor of any one of Claims 1-4 performed by being immersed over 10 hours-2 weeks. The negative electrode current collector and the positive electrode current collector have through holes, the positive electrode active material layer is formed on both surfaces or one surface of the positive electrode current collector, and the negative electrode active material layer is The negative electrode current collector is formed on both sides or one side, and before the pre-doping process, a lithium metal foil is opposed to at least one layer selected from the positive electrode active material layer and the negative electrode active material layer In the case of obtaining the pre-doped laminate by laminating the separator between the negative electrode active material layer and the positive electrode active material layer,
In the pre-doping treatment step, the pre-doped laminate is applied to the first non-aqueous electrolyte solution at a temperature of 40 ° C. to 50 ° C. for 10 hours to 72 hours, or at a temperature of less than 40 ° C. for 10 hours to 2 hours. The manufacturing method of the lithium ion capacitor of any one of Claims 1-4 performed by immersing over a week. The negative electrode active material is a composite porous material in which a carbon material is deposited on the surface of activated carbon, 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 ), When the amount of micropores derived from pores having a diameter of less than 20 mm calculated by the MP method is Vm2 (cc / g),
0.010 ≦ Vm1 ≦ 0.250,
The method for manufacturing a lithium ion capacitor according to claim 1, wherein 0.001 ≦ Vm2 ≦ 0.200 and 1.5 ≦ Vm1 / Vm2 ≦ 20.0 are satisfied. In the positive 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 amount of micropores derived from pores having a diameter of less than 20 mm calculated by the MP method. Is V2 (cc / g),
It is activated carbon that satisfies 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and has a specific surface area measured by the BET method of 1500 m ² / g or more and 3000 m ² / g or less. Item 8. The method for producing a lithium ion capacitor according to any one of Items 1 to 7.

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