KR102561404B1 - Electric double layer capacitor eleclyte, electric double layer capacitor using the electrolyte and manufacturing method of the electric double layer capacitor - Google Patents

Abstract

The present invention is an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent, wherein the tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis(fluorosulfonyl)imide (bis (fluorosulfonyl) imide) is a salt in which one or more substances selected from the group consisting of an anion form, or one alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation. and NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis (Fluorosulfonyl) imide (bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) characterized in that at least one material selected from the salt constituting an anion, an electrolyte for an electric double layer capacitor, an electric double layer capacitor using the same and a method for manufacturing the same it's about According to the present invention, a tertiary ammonium salt containing three alkyl groups and one hydrogen (H) can also be used as an electrolyte for an electric double layer capacitor.

Description

Electric double layer capacitor eleclyte, electric double layer capacitor using the electrolyte and manufacturing method of the electric double layer capacitor}

The present invention relates to an electrolyte, an electric double-layer capacitor using the same, and a manufacturing method thereof, and more particularly, to an electrolyte solution for an electric double-layer capacitor to which a tertiary ammonium salt is applied, an electric double-layer capacitor using the same, and a manufacturing method thereof.

In general, an Electric Double Layer Capacitor (EDLC) is also referred to as a super-capacitor or ultra-capacitor, which has a code at the interface of an electrode and a conductor and an electrolyte solution impregnated therein, respectively. is a device in which a pair of charge layers (electric double layers) are generated, and deterioration due to repetition of charge/discharge operations is very small and maintenance is not required. Accordingly, electric double layer capacitors are mainly used in the form of backing up IC (integrated circuit) of various electrical and electronic devices, and recently, their use has been expanded to include toys, solar energy storage, and HEV (hybrid electric vehicle) power supplies. It is becoming.

Such an electric double layer capacitor (EDLC) generally has two electrodes, an anode and a cathode, impregnated with an electrolyte, and a porous separator interposed between these two electrodes to enable only ion conduction and to insulate and prevent short circuits. ), a gasket to prevent leakage of the electrolyte, insulation and short circuit, and a unit cell composed of a metal cap as a conductor for packaging them. In addition, one or more unit cells configured as above (usually, 2 to 6 in the case of a coin type) are stacked in series and the two terminals of the anode and the cathode are combined to complete.

The performance of an electric double layer capacitor (EDLC) is determined by an electrode active material and an electrolyte. Activated carbon is mainly used as an electrode active material, and its specific capacitance is known to be up to 19.3 F/cc based on the electrode of a commercial product.

An electric double layer capacitor (EDLC) is an energy storage medium that can be excellently used in situations where rapid energy supply is required due to its high output characteristics and excellent durability. However, since the electric double layer capacitor is a medium for storing energy using adsorption of ions, desorption of ions also occurs easily, which means loss of stored energy.

Republic of Korea Patent Registration No. 10-1567771

The problem to be solved by the present invention is to provide an electrolyte solution for an electric double layer capacitor to which tertiary ammonium salt is applied, an electric double layer capacitor using the same, and a manufacturing method thereof.

The present invention is an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent, wherein the tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis(fluorosulfonyl)imide (bis (fluorosulfonyl) imide) is a salt in which one or more substances selected from the group consisting of an anion form, or one alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation. and NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis Provided is an electrolyte solution for an electric double layer capacitor, characterized in that a salt in which at least one material selected from the group consisting of (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) forms an anion.

The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

In addition, in the present invention, the positive electrode and the negative electrode are disposed to be spaced apart from each other, and a separator is disposed between the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode, and the positive electrode, the separator, and the negative electrode are 3 It is impregnated in an electrolyte solution containing a primary ammonium salt and a solvent, and the tertiary ammonium salt is formed by bonding three alkyl groups and one hydrogen (H) to nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis(fluorosulfonyl)imide (bis( One or more substances selected from the group consisting of fluorosulfonyl) imide) are salts forming an anion, or one alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation and NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis(fluoro Provided is an electric double layer capacitor, characterized in that at least one material selected from the group consisting of sulfonyl) imide (bis (fluorosulfonyl) imide) is a salt forming an anion.

The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

In addition, the present invention includes the steps of preparing a composition for an electrode by mixing an electrode active material, a conductive material, a binder, and a dispersion medium, and forming the composition for an electrode by compressing the composition for an electrode to form an electrode, or forming the composition for an electrode using a metal foil or a current collector Forming an electrode by coating on the electrode, or pushing the composition for the electrode with a roller to form a sheet and attaching it to a metal foil or a current collector to form an electrode, and drying the result formed in the electrode to form an electric double layer capacitor electrode and using the electric double layer capacitor electrode as an anode and a cathode, disposing a separator between the anode and the cathode to prevent a short circuit between the anode and the cathode, and placing the anode, the separator, and the cathode in a tertiary It includes the step of impregnating an electrolyte solution containing an ammonium salt and a solvent, wherein the tertiary ammonium salt is formed by combining three alkyl groups and one hydrogen (H) with nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis(fluorosulfonyl)imide ( At least one material selected from the group consisting of bis (fluorosulfonyl) imide) is a salt forming an anion, or a cation is formed by combining one alkyl group, one pyridine or pyreridine, and one hydrogen (H) with nitrogen. NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis( Provided is a method for manufacturing an electric double layer capacitor, characterized in that at least one material selected from the group consisting of fluorosulfonyl) imide (bis (fluorosulfonyl) imide) is a salt forming an anion.

The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

According to the present invention, a tertiary ammonium salt containing three alkyl groups and one hydrogen (H) can also be used as an electrolyte for an electric double layer capacitor.

In addition, according to the electrolyte solution of the present invention, the capacitance of the electric double layer capacitor can be improved.

1 is a view showing the structure of a tertiary ammonium salt according to an example.
2 is a view showing the structure of a tertiary ammonium salt according to another example.
3 is a diagram showing a state of use of an electric double layer capacitor according to an example.
4 is a view showing the structure of TriMA BF ₄ synthesized according to the experimental example.
5 is a graph showing rate characteristics (output characteristics, rate capability) measured using TriMA BF ₄ and TEA BF ₄ electrolyte salt in anhydrous acetonitrile solvent.
6 is a graph showing rate characteristics (output characteristics, rate capability) measured using TriMA BF ₄ and TEA BF ₄ electrolyte salt in γ-butyrolactone solvent.
7 is a view showing the results of testing the lifespan characteristics of TriMA BF ₄ .

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided to those skilled in the art to sufficiently understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the following examples. it is not going to be

When it is said that any one component "includes" another component in the detailed description or claims of the invention, it is not construed as being limited to only the corresponding component unless otherwise stated, and other components are not further defined. It should be understood that it can include.

An electrolyte solution for an electric double layer capacitor according to a preferred embodiment of the present invention is an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent, wherein the tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form cations NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) ) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) is a salt in which one or more substances selected from the group consisting of an anion form, or one alkyl group, one pyridine or pyreridine, and one Hydrogen (H) is bonded to nitrogen to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , bis(trifluoromethanesulfone) It is a salt in which at least one material selected from the group consisting of Bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide forms an anion.

The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

In the electric double layer capacitor according to a preferred embodiment of the present invention, an anode and a cathode are disposed to be spaced apart from each other, a separator is disposed between the anode and the cathode to prevent a short circuit between the anode and the cathode, and the anode, The separator and the cathode are impregnated with an electrolyte containing a tertiary ammonium salt and a solvent, and the tertiary ammonium salt is formed by combining three alkyl groups and one hydrogen (H) with nitrogen (N) to form a cation and NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) and bis(fluorosulfonimide) One or more substances selected from the group consisting of phonyl) imide (bis (fluorosulfonyl) imide) is a salt forming an anion, or one alkyl group, one pyridine or pyreridine, and one hydrogen (H) on nitrogen Combined to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br - , I ^- , CN ^- , BF ₄ ^{- ,} PF ₆ ^- , ClO ₄ ^- , Bis(trifluoromethanesulfonimide) (Bis(trifluoromethanesulfonimide) )) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) is a salt of at least one material selected from the group consisting of an anion.

The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

A method for manufacturing an electric double layer capacitor according to a preferred embodiment of the present invention includes preparing a composition for an electrode by mixing an electrode active material, a conductive material, a binder, and a dispersion medium, and pressing the composition for an electrode to form an electrode form, coating the composition for an electrode on a metal foil or a current collector to form an electrode form, or forming a sheet state by pushing the composition for an electrode with a roller and attaching the composition for an electrode to a metal foil or a current collector to form an electrode form; Drying the resulting product to form an electric double layer capacitor electrode, using the electric double layer capacitor electrode as an anode and a cathode, and disposing a separator between the anode and the cathode to prevent a short circuit between the anode and the cathode, Impregnating the positive electrode, the separator, and the negative electrode in an electrolyte solution containing a tertiary ammonium salt and a solvent, wherein the tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form a cation Forming NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , Bis (trifluoromethanesulfonimide) (Bis (trifluoromethanesulfonimide)) and A salt in which at least one material selected from the group consisting of bis (fluorosulfonyl) imide forms an anion, or one alkyl group, one pyridine or pyreridine, and one hydrogen ( H) is bonded to nitrogen to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , bis(trifluoromethanesulfonimide ) (Bis (trifluoromethanesulfonimide)) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) at least one material selected from the group consisting of a salt forming an anion.

The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

Hereinafter, an electrolyte solution for an electric double layer capacitor according to a preferred embodiment of the present invention will be described in more detail.

Typically, electric double layer capacitors (EDLCs) use quaternary ammonium salts without hydrogen ions. Quaternary ammonium salts have good durability against electrolysis, enabling EDLC for 3V.

However, in the present invention, an electrolyte solution containing a tertiary ammonium salt is used.

An electrolyte solution for an electric double layer capacitor according to a preferred embodiment of the present invention is an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

The tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF At least one material selected from the group consisting of ₆ ^- , ClO ₄ ^- , bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (Bis (trifluoromethanesulfonimide)) It may be a salt that forms an anion. The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl. 1 is a diagram showing the structure of such a tertiary ammonium salt. In FIG. 1, R1, R2 and R3 are alkyl groups, and X is an anion.

In the tertiary ammonium salt, one alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , consisting of bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) At least one material selected from the group may be a salt forming an anion. The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl. 2 is a diagram showing the structure of such a tertiary ammonium salt. In FIG. 2, R4 is an alkyl group and X is an anion.

Hereinafter, an electric double layer capacitor according to a preferred embodiment of the present invention will be described in more detail.

An electric double layer capacitor (EDLC) is an energy storage medium that can be excellently used in situations where rapid energy supply is required due to its high output characteristics and excellent durability. However, since the electric double layer capacitor is a medium for storing energy using adsorption of ions, desorption of ions also occurs easily, which means loss of stored energy.

An electric double layer capacitor according to a preferred embodiment of the present invention is an electric double layer capacitor in which a separator is disposed between an anode and a cathode to prevent a short circuit between the anode and the cathode, and the anode and the cathode are impregnated with an electrolyte solution.

The electrolyte solution is an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

The tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF At least one material selected from the group consisting of ₆ ^- , ClO ₄ ^- , bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (Bis (trifluoromethanesulfonimide)) It may be a salt that forms an anion. The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl. 1 is a diagram showing the structure of such a tertiary ammonium salt. In FIG. 1, R1, R2 and R3 are alkyl groups, and X is an anion.

In the tertiary ammonium salt, one alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , consisting of bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) At least one material selected from the group may be a salt forming an anion. The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl. 2 is a diagram showing the structure of such a tertiary ammonium salt. In FIG. 2, R4 is an alkyl group and X is an anion.

The separator is a polyethylene non-woven fabric, a polypropylene non-woven fabric, a polyester non-woven fabric, a polyacrylonitrile porous separator, a poly(vinylidene fluoride) hexafluoropropane copolymer porous separator, a cellulose porous separator, kraft paper or rayon fiber, etc. Batteries and capacitors It is not particularly limited as long as it is a separator generally used in the field.

The positive electrode and the negative electrode are prepared by mixing an electrode active material, a conductive material, a binder, and a dispersion medium to prepare a composition for an electrode, and forming the composition in an electrode form by compressing the composition for an electrode, or applying the composition for an electrode to a metal foil or a current collector. It may be formed in the form of an electrode, or it may be manufactured by pushing the composition for the electrode with a roller to form a sheet and attaching it to a metal foil or a current collector to form an electrode form, and drying the resultant formed in the form of an electrode.

The electrode active material for preparing the electrode may be activated carbon or the like.

The conductive material is not particularly limited as long as it is an electron conductive material that does not cause chemical change, and examples thereof include natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder or metal such as copper, nickel, aluminum, and silver. fibers and the like.

The binder is polytetrafluoroethylene (PTFE), polyvinylidenefloride (PVdF), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB). from poly vinyl butyral), poly-N-vinylpyrrolidone (PVP), styrene butyl rubber (SBR), polyamide-imide, polyimide, etc. One selected type or a mixture of two or more types may be used.

As the dispersion medium, organic solvents such as ethanol (EtOH), acetone, isopropyl alcohol, N-methylpyrrolidone (NMP), and propylene glycol (PG) or water may be used.

Hereinafter, a method of manufacturing an electric double layer capacitor according to a preferred embodiment of the present invention will be described in more detail.

Electrodes can be prepared as follows.

A composition for an electrode in which an electrode active material, a binder, a conductive material, and a dispersion medium are mixed is compressed to form an electrode, or the composition for an electrode is coated on a metal foil or a current collector to form an electrode, or the composition for an electrode is formed with a roller. It is pushed into a sheet state and attached to a metal foil or a current collector to form an electrode form.

The electrodes (anode and cathode) prepared as described above can be usefully applied to electric double layer capacitors.

3 is a state diagram of a use of an electric double layer capacitor according to an example, showing a cross-sectional view of a coin-type electric double layer capacitor to which an electrode of the electric double layer capacitor is applied. In FIG. 1, reference numeral 190 denotes a metal cap as a conductor, reference numeral 160 denotes a separator made of a porous material for insulation and short circuit prevention between the anode 120 and the cathode 110, and reference numeral 192 denotes electrolyte leakage. It is a gasket for insulation and short circuit prevention. At this time, the positive electrode 120 and the negative electrode 110 are firmly fixed by the metal cap 190 and the adhesive.

The coin-type electric double layer capacitor is disposed between the above-described positive electrode 120, negative electrode 110, positive electrode 120 and negative electrode 110, and a separator for preventing a short circuit between the positive electrode 120 and the negative electrode 120 ( Seperator 160 may be placed in the metal cap 190, an electrolyte in which electrolyte is dissolved may be injected between the anode 120 and the cathode 110, and then sealed with a gasket 192.

The electrolyte solution is an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent.

The solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,2- Among dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, ethanol and H ₂ O It may contain one or more selected materials.

The tertiary ammonium salt has three alkyl groups and one hydrogen (H) bonded to nitrogen (N) to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF At least one material selected from the group consisting of ₆ ^- , ClO ₄ ^- , bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (Bis (trifluoromethanesulfonimide)) It may be a salt that forms an anion. The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl. 1 is a diagram showing the structure of such a tertiary ammonium salt. In FIG. 1, R1, R2 and R3 are alkyl groups, and X is an anion.

In the tertiary ammonium salt, one alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation, NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , consisting of bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) At least one material selected from the group may be a salt forming an anion. The alkyl group may be composed of methyl, ethyl, propyl, isopropyl, or butyl. 2 is a diagram showing the structure of such a tertiary ammonium salt. In FIG. 2, R4 is an alkyl group and X is an anion.

The separator is a polyethylene non-woven fabric, a polypropylene non-woven fabric, a polyester non-woven fabric, a polyacrylonitrile porous separator, a poly(vinylidene fluoride) hexafluoropropane copolymer porous separator, a cellulose porous separator, kraft paper or rayon fiber, etc. Batteries and capacitors It is not particularly limited as long as it is a separator generally used in the field.

Hereinafter, experimental examples according to the present invention are specifically presented, and the present invention is not limited to the experimental examples presented below.

TriMA BF ₄ is a tertiary ammonium salt containing hydrogen ions. Typically, electric double layer capacitors (EDLCs) use quaternary ammonium salts without hydrogen ions. Quaternary ammonium salts have good durability against electrolysis, enabling EDLC for 3V.

This experiment is for tertiary ammonium containing one hydrogen ion, and of course it is not possible to use it at a voltage such as 3V. However, it was determined that this structure would have a reasonable use, and the voltage provided by this structure was observed, and the physical properties (viscosity, conductivity) were confirmed to confirm the use area of the tertiary ammonium salt.

Tertiary ammonium salts are suitable for capacitors that provide 1.8 V, which is about twice the voltage of aqueous solutions, and the use of γ-butyrolactone (GBL; γ-Butyloractone) as a solvent helps to inhibit electrochemical decomposition. Electrolyte salts containing hydrogen can be used in pseudo-capacitors, which are capacitors that require hydrogen, and provide a voltage twice as high as the sulfuric acid aqueous solution used by pseudo-capacitors. You can use your weaknesses by turning them into strengths.

In addition, the structure of the tertiary ammonium used in this experiment is trimethylammonium tetrafluoroborate, which is the simplest structure, so if you use tertiary ammonium substituting various alkyl structures instead of methyl, It is expected that various applications will occur as it can be extended to a higher voltage than the implemented 1.8V.

The experiment proceeded as follows.

1. EDLC electrode fabrication

When manufacturing the EDLC electrode, activated carbon MSP20 as an electrode active material, carbon black (super p black, MMM, belgium) as a conductive material, and carboxymethylcellulose (CMC; Carboxymethylcellulose) (Sigma-Aldrich) aqueous solution (water ( H ₂ O) 99.9wt% and an aqueous solution containing 1.1wt% of carboxymethylcellulose) and styrene butyl rubber (SBR; Styrene butyl rubber) (Zeon, BM-400B) were used.

First, activated carbon, conductive material, and carboxymethylcellulose (CMC) aqueous solution were mixed, kneaded and mixed, and then styrene butyl rubber (SBR) and distilled water were added and mixed again to prepare a slurry. At this time, the weight ratio of activated carbon, conductive material, styrene butyl rubber (SBR), and carboxymethyl cellulose (CMC) is 81:12.8:4.2:2.

The prepared slurry was applied to an aluminum current collector using a knife coating device (KP-3000VH, KPAE ENT Co., Ltd.) and dried in an oven at 80°C.

The electrode thus prepared had a thickness of about 150 μm, and after rolling the dried electrode, it was dried in a vacuum oven at about 60° C. for 12 hours and stored.

2. Electrolytic salt synthesis

As the electrolyte salt, two types of tetraethylammonium tetrafluoroborate (TEA BF ₄ ) and trimethylammonium tetrafluoroborate (TriMA BF ₄ ) were used.

First, the synthesis process of TEA BF ₄ is as follows. Tetraethylammonium bromide (TEA Br, Tokyo Chemical Industry Co., Ltd, 98.0%) and tetrafluoroboric acid solution (HBF ₄ , Alfa Aesar Co., Inc.) (a solution containing 50 wt% of water (H ₂ O) and 50 wt% of tetrafluoroboric acid) was reacted at a molar ratio of 1: 1.1 at room temperature for one day. At this time, about 200 ml of acetonitrile (AN; Acetonitrile) (Samchun oure chemical CO., LTD, 99.8%) was used as a solvent. TEA BF ₄ produced after the reaction is a white solid salt dissolved in acetonitrile (AN) as a solvent. After removing the solvent and unreacted HBF ₄ using a vacuum concentrator, precipitating the salt with n-Butanol (Daejun Chemicals & Metals Co., Ltd), and then sufficiently using n-Butanol A salt was obtained by washing and filtration under reduced pressure. After re-dissolving the salt in acetonitrile (AN), impurities were removed through recrystallization and concentration. Thereafter, vacuum drying was performed for about 3 to 4 days, and at this time, the salt was heated to about 40 ° C. while stirring.

The synthesis process of TriMA BF ₄ is as follows. Trimethylamine solution (Tokyo Chemical Industry Co., Ltd) (a solution containing 87 wt% of tetrahydrofuran and 13 wt% of trimethylamine) and tetrafluoroboric acid solution were placed in a 500 ml round bottom flask. ) (HBF ₄ , Alfa Aesar Co., Inc.) (a solution containing 50 wt% of water (H ₂ O) and 50 wt% of tetrafluoroboric acid) at a molar ratio of 1: 1.1 in an ice bath for one day. made When an excessive amount of HBF ₄ is added, the crystals dissolve again and the solution becomes clear. The solvent and excess HBF ₄ are removed using a vacuum concentrator to give a white solid salt. It can be precipitated with n-butanol, washed, and filtered under reduced pressure to obtain a salt. Similarly, it was dissolved in acetonitrile (AN) and recrystallized. Vacuum drying was performed for about 3 to 4 days while heating at about 40°C. 4 shows the structure of TriMA BF ₄ thus synthesized. Referring to FIG. 4 , TriMA BF ₄ is a tertiary ammonium salt, in which three methyl groups and one hydrogen (H) are bonded to nitrogen (N) to form a cation and BF ₄ ^- to form an anion.

3. Coin cell assembly

An electrolyte was first prepared in a glove box (Korea Kiyon Co., Ltd) filled with argon gas, and then a coin cell was assembled.

The solvents used in the electrolyte were acetonitrile anhydrous (AN, Alfa Aesar Co., Inc, >99.8%, HPLC grade, far UV) and γ-butyrolactone (GBL, Sigma-Aldrich Co. ., Ltd) were used. 1.0M TEABF ₄ and 1.0M TriMA BF ₄ were prepared in the solvent anhydrous acetonitrile, and 1.0M TEA BF ₄ and 1.0M TriMA BF ₄ were prepared in the solvent γ-butyrolactone.

A 2032-type coin cell (Hohsen Co.) was used as the coin cell, and the separator was cellulose (Ø 19 mm, thickness 40 μm), spacer (Ø 16 mm, thickness 1.0 mm) ), a wave spring (Ø15 mm, thickness 1.4 mm) was used, and 75 μl of electrolyte was injected and sealed with an automatic coin cell crimper (Hohsen co.).

4. Capacity measurement using a coin cell

TriMA BF ₄ electrolyte salt is an electrolyte salt suitable for a voltage of 2V or less because the electrolyte salt is decomposed at a voltage of 2V or higher. Instead, since it provides a voltage nearly twice as high as the voltage of less than 1V provided by an aqueous solution, it provides a voltage in the middle region between a capacitor using an aqueous solution (1V) and a general non-aqueous solution capacitor (3V). In this experiment, it was charged with 1.8 V as the upper limit voltage and discharged to 0 V to confirm life safety.

5 is a graph showing rate characteristics (output characteristics, rate capability) measured using TriMA BF ₄ and TEA BF ₄ electrolyte salt in anhydrous acetonitrile solvent.

Referring to FIG. 5 , TriMA BF ₄ provided lower capacitance than TEA BF ₄ in anhydrous acetonitrile solvent. However, it responded well to the current change and showed a rate characteristic graph similar to that of the TEA BF ₄ solution.

6 is a graph showing rate characteristics (output characteristics, rate capability) measured using TriMA BF ₄ and TEA BF ₄ electrolyte salt in γ-butyrolactone solvent.

Referring to FIG. 6 , TriMA BF ₄ provided higher capacitance than TEA BF ₄ in an electrolytic salt using a γ-butyrolactone solvent.

As shown in FIG. 6, the reason why TriMA BF ₄ electrolyte salt provides excellent capacitance is that TriMA BF ₄ has higher conductivity and lower viscosity than TEA BF ₄ in γ-butyrolactone solvent, as shown in Table 1 below. .

Table 1 below shows the results of measuring the conductivity and viscosity of the electrolyte at a concentration of 1 M, and the measurement temperature is 25 ° C.

Electrolytes TEA BF ₄ /AN TriMA BF ₄ /AN TEA BF ₄ /GBL TriMA BF ₄ /GBL Conductivity, mS cm ^-1 56 49.6 18 [18] 18.7 Viscosity, mPa s 0.569 0.503 2.454 2.280

5, 6 and Table 1, it can be confirmed that TriMA BF ₄ provides better properties than TEA BF ₄ electrolyte salt when using γ-butyrolactone (GBL) solvent. This means that along with the characteristic that γ-butyrolactone (GBL) has a high boiling point, TriMA BF ₄ shows characteristics that can be used for capacitors to which voltages around 2V and high temperatures are applied.

The reason TriMA BF ₄ cannot be used at high voltage is that it decomposes at high voltage. Then, cycle life tests were measured to confirm whether it could be used for a long time at medium voltage.

7 is a view showing the results of testing the lifespan characteristics of TriMA BF ₄ . 6000 cycles were operated using anhydrous acetonitrile (AN) and γ-butyrolactone (GBL) as the solvent, respectively.

Referring to FIG. 7 , when TriMA BF ₄ drives a capacitor with an upper limit voltage of 1.8 V, it shows that the capacity is well maintained up to 6000 cycles. When γ-butyrolactone (GBL) was used, the capacitance increased during the initial 3000 cycles because of the high viscosity, indicating that it takes time to sufficiently impregnate the electrode. After 3000 cycles, in a capacitor where wetting is complete, when γ-butyrolactone (GBL) is used, a higher capacity is provided than when anhydrous acetonitrile (AN) is used. This is because the electrolyte decomposition rate is slower when γ-butyrolactone (GBL) is used than when anhydrous acetonitrile (AN) is used.

The results of FIG. 7 show that after the electrode is sufficiently impregnated, even if the conductivity and viscosity of the electrolyte solution is low, it does not cause a significant problem in capacity. According to the results, if the γ-butyrolactone (GBL) solvent having a slightly higher viscosity is used, it can be used reliably for medium voltage capacitors because the decomposition of the electrolyte can be sufficiently suppressed.

TriMA BF ₄ has characteristics that can be used at medium voltage (around 2V) and high temperature. And, as shown in FIGS. 1 and 2 , when there are protons, it can be used as a pseudo-capacitor. In particular, since an aqueous solution of sulfuric acid is used to provide a higher voltage than a pseudo-capacitor (less than 1V) receiving hydrogen ions, it can be used as an electrolyte for a pseudo-capacitor.

Figures 1 and 2 suggest the structural scalability that the alkyl group can be variously changed in the structure of three methyl groups of TriMA BF ₄ . R ₁ , R ₂ , R ₃ , R ₄ , R ₅ may be a preceding alkyl such as methyl, ethyl, propyl, isopropyl, or butyl. In addition, two of the alkyl groups form a cyclic structure to form a cyclic tertiary ammonium salt. Here, the X-ion constituting the anion is NO ₃ ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , bis(trifluoromethanesulfonimide ) (Bis(trifluoromethanesulfonimide)) and bis(fluorosulfonyl)imide.

Among these modified structures, there will be tertiary ammonium that provides a higher voltage than TriMA BF ₄ , and a structure in which decomposition is inhibited even when using a solvent that provides high conductivity such as acetonitrile (AN) will be found. Through this, the utilization of the medium voltage region will be further improved and applied to the operation of the pseudo-capacitor that provides a much higher voltage than the medium voltage EDLC and aqueous solution.

In the above, the preferred embodiment of the present invention has been described in detail, but the present invention is not limited to the above embodiment, and various modifications are possible by those skilled in the art.

110: cathode
120: anode
160: separator
190: metal cap
192: gasket

Claims (9)

As an electrolyte solution in which a tertiary ammonium salt is dissolved in a solvent,
The tertiary ammonium salt,
Three alkyl groups and one hydrogen (H) are bonded to nitrogen (N) to form a cation, CN ^- , Bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) is a salt in which one or more substances selected from the group consisting of an anion form,
One alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation, CN ^- , Bis(trifluoromethanesulfonimide) and bis(fluoromethane). An electrolyte solution for an electric double layer capacitor, characterized in that at least one material selected from the group consisting of bis (fluorosulfonyl) imide is a salt forming an anion.
[Claim 2] The electrolyte solution for an electric double layer capacitor according to claim 1, wherein the alkyl group is composed of methyl, ethyl, propyl, isopropyl or butyl.
The method of claim 1, wherein the solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, propionic acid Ethyl, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, An electrolyte solution for an electric double layer capacitor comprising at least one material selected from ethanol and H ₂ O.
The positive and negative electrodes are spaced apart from each other,
A separator is disposed between the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode,
The positive electrode, the separator, and the negative electrode are impregnated with an electrolyte solution containing the tertiary ammonium salt according to claim 1 and a solvent,
The tertiary ammonium salt,
Three alkyl groups and one hydrogen (H) are bonded to nitrogen (N) to form a cation, CN ^- , Bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) is a salt in which one or more substances selected from the group consisting of an anion form,
One alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation, CN ^- , Bis(trifluoromethanesulfonimide) and bis(fluoromethane). An electric double layer capacitor, characterized in that at least one material selected from the group consisting of bis (fluorosulfonyl) imide is a salt forming an anion.
5. The electric double layer capacitor according to claim 4, wherein the alkyl group is composed of methyl, ethyl, propyl, isopropyl or butyl.
The method of claim 4, wherein the solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, propionic acid Ethyl, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, An electric double layer capacitor comprising at least one material selected from ethanol and H ₂ O.
preparing a composition for an electrode by mixing an electrode active material, a conductive material, a binder, and a dispersion medium;
The composition for an electrode is compressed to form an electrode form, the composition for an electrode is coated on a metal foil or a current collector to form an electrode form, or the composition for an electrode is pressed with a roller to form a sheet and is coated on a metal foil or a current collector attaching to form an electrode;
drying the product formed in the form of an electrode to form an electric double layer capacitor electrode; and
The electric double layer capacitor electrode is used as an anode and a cathode, and a separator is disposed between the anode and the cathode to prevent a short circuit between the anode and the cathode, and the anode, the separator, and the cathode according to claim 1 are disposed. Impregnating in an electrolyte solution containing a tertiary ammonium salt and a solvent,
The tertiary ammonium salt,
Three alkyl groups and one hydrogen (H) are bonded to nitrogen (N) to form a cation, CN ^- , Bis (trifluoromethanesulfonimide) and bis (fluorosulfonyl) imide (bis (fluorosulfonyl) imide) is a salt in which one or more substances selected from the group consisting of an anion form,
One alkyl group, one pyridine or pyreridine, and one hydrogen (H) are bonded to nitrogen to form a cation, CN ^- , Bis(trifluoromethanesulfonimide) and bis(fluoromethane). A method of manufacturing an electric double layer capacitor, characterized in that at least one material selected from the group consisting of bis (fluorosulfonyl) imide is a salt forming an anion.
8. The method of claim 7, wherein the alkyl group is composed of methyl, ethyl, propyl, isopropyl or butyl.
The method of claim 7, wherein the solvent is acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, propionic acid Ethyl, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, γ-butyrolactone, dimethylformamide, acetone, methanol, A method for manufacturing an electric double layer capacitor comprising at least one material selected from ethanol and H ₂ O.