KR101095863B1 - Electrode of super capacitor for high power and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an electrode of a high output supercapacitor capable of improving electrical conductivity and increasing capacitance by using a carbon aerogel having a three-dimensional network structure doped with a transition metal, and a method of manufacturing the high output supercapacitor according to the present invention. The electrode of the capacitor is composed of a transition metal doped carbon aerogel 50 to 87wt%, activated carbon 5 to 20wt%, conductive agent 3 to 10wt%, binder 5 to 20wt%, the transition metal doped carbon aerogel By using this method, the electroconductivity can be improved and the capacitance can be increased through the chemical redox reaction of the transition metal. Also, by improving the electrical conductivity, the equivalent series resistance is reduced, thereby increasing the charge transfer rate at the interface between the electrode and the electrolyte. This increases the time required for the current to reach a steady state, thereby enabling rapid charge / discharge.

Description

Electrode of high power super capacitor and its manufacturing method

The present invention relates to an electrode of a high output supercapacitor and a method of manufacturing the same. More particularly, the electrical conductivity is improved by using a carbon aerogel, activated carbon and a conductive agent having a 3D network structure doped with a transition metal. In addition, the present invention relates to an electrode of a high output super capacitor capable of increasing capacitance and a method of manufacturing the same.

Smart grid is a next-generation intelligent grid that optimizes energy efficiency by integrating information technology into the existing grid to exchange real-time information in both directions. These smart grids use super capacitors as high-capacity energy storage devices to reduce the power load gap between night and day, to improve the stability of the entire power system, to realize high capacity, high power density and fast response speed.

Supercapacitors can be used as energy storage devices in various fields due to their rapid charge / discharge, high charge / discharge efficiency, and semi-permanent cycle life. Electric double layer capacitor (EDLC) is used. Supercapacitor electrodes to which an electric double layer capacitor is applied generally consist of porous activated carbon, a conductive agent and a binder.

Activated carbon is a microporous porous material with a large specific surface area, so when (-) is applied to activated carbon, (+) ions released from the electrolyte enter the pores of the activator to form a (+) layer, which is formed at the interface of the activator ( The charge is charged by forming a double layer and an electric double layer. As the active agent, one of activated carbon powder, carbon nanotubes and carbon aerogels is used. In addition, the conductive agent is added to impart conductivity to the electrode material, and carbon black is used.

The density, resistance and charge capacity of the electrode of a conventional supercapacitor composed of activated carbon, a conductive agent and a binder are closely related to the mixing ratio of the activated carbon and the conductive agent. For example, when the content of the conductive agent is increased, the resistance is decreased due to the high electrical conductivity of the conductive material, but since the lower specific surface area is lower than that of the active agent, the charging capacity of the conventional super capacitor is reduced as a whole.

Conventional supercapacitors have an increased capacitance due to an increase in the amount of activated carbon having a high specific surface area, but relatively low content of a conducting agent, resulting in low electrical conductivity, which leads to difficulty in implementing high output characteristics of the supercapacitor. .

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, by using carbon aerogels, activated carbon and conductive agents having a 3D network structure doped with a transition metal to improve electrical conductivity as well as the transition metal. The present invention provides an electrode of a high power super capacitor capable of increasing capacitance through a chemical redox reaction and a method of manufacturing the same.

Another object of the present invention is to improve the electrical conductivity, the equivalent series resistance (ESR) is reduced to increase the charge transfer rate at the interface between the electrode and the electrolyte, thereby increasing the time for the current to reach a steady state is possible to fast charge / discharge An electrode of a high output super capacitor and a method of manufacturing the same are provided.

The electrode of the high power supercapacitor of the present invention is a carbon aerogel doped with a transition metal, activated carbon, a conductive agent and a binder ratio of a carbon aerogel doped with a transition metal 50 to 87 wt%, activated carbon 5 to 20 wt%, and a conductive agent 3 ~ It is characterized by consisting of 10wt% and 5 to 20wt% of the binder.

Electrode manufacturing method of the high output super capacitor of the present invention comprises the steps of preparing a carbon airgel; Preparing a carbon aerogel doped with a transition metal by doping a transition metal to the carbon aerogel when the carbon aerogel is prepared; Preparing an active material by mixing activated carbon and a conductive agent in a carbon airgel doped with a transition metal when the transition metal is doped; When the active material is prepared, a process of preparing a slurry by mixing the active material with a binder; and when the slurry is prepared, is characterized by consisting of applying the slurry to the current collector.

The present invention provides an electrode of a high output supercapacitor and a method of manufacturing the same by using a carbon aerogel doped with a transition metal to improve electrical conductivity and to increase capacitance through chemical redox reaction of the transition metal. In addition, by improving the electrical conductivity, the equivalent series resistance is reduced, thereby increasing the charge transfer rate at the interface between the electrode and the electrolyte, thereby providing the advantage that a rapid charging / discharging is possible because the time is reached to reach a steady state.

1 is a flow chart showing a manufacturing process of a carbon aerogel doped with a transition metal of the present invention,
FIG. 2 is a flow chart showing a manufacturing process of an electrode of a high output super capacitor using a carbon aerogel doped with a transition metal shown in FIG. 1;
3 is a transmission electron micrograph of a carbon airgel
4 is a table showing representative electrical characteristics of the electrode of the high power super capacitor.

Hereinafter, an embodiment of an electrode of a high output supercapacitor of the present invention and a manufacturing method thereof will be described with reference to the accompanying drawings.

The electrode of the high power supercapacitor of the present invention is composed of a transition metal doped carbon aerogel, activated carbon, a conductive agent and a binder, each ratio is a transition metal doped carbon aerogel 50 ~ 87wt%., Activated carbon 5 ~ 20wt% And 3 to 10 wt% of a conductive agent and 5 to 20 wt% of a binder. Here, the carbon aerogel doped with a transition metal has a three-dimensional network (3D-network) structure as shown in FIG. 3 to improve electrical conductivity and increase capacitance through chemical redox reaction of the transition metal. . In addition, by improving the electrical conductivity, the electrode of the high-power supercapacitor of the present invention has a reduced internal resistance (DS-ESR) as shown in the table shown in FIG. 4, thereby increasing the charge transfer rate at the interface between the electrode and the electrolyte, and thus the current. The time to reach the steady state is increased to provide the advantage that the rapid charging / discharging is possible.

The electrode of the high-power supercapacitor of the present invention to enable rapid charge / discharge is cobalt (Co), ruthenium (Ru), manganese (Mn), vanadium (V), tin (Sn) in a carbon aerogel doped with a transition metal. And a transition metal of one of lithium (Li), the doped transition metal has a precursor shape, and fine particles having a diameter of 20 to 200 nm are used.

One of the conductive agents, carbon black and super-p carbon, is used to improve electrical conductivity with carbon aerogels doped with transition metals. That is, the electrode of the high output supercapacitor of the present invention uses a carbon aerogel doped with a transition metal to prevent an increase in the internal resistance (DS-ESR) without lowering the electrical conductivity even when a small amount of the conductive agent is used. . Super-p carbon is essentially a material in which molecular sieve materials such as carbon molecular sieve are dispersed in a polymer matrix, and has been developed for gas separation applications such as nitrogen production from air as an alternative to existing polymer membranes.

As a binder for mixing the active agent and the conductive agent, one of polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC) and stylen-buthylene-rubber (SBR) is used to uniformly mix the active agent and the conductive agent.

Example 1 (carbon aerogel + conductive agent + binder doped with a transition metal) and Example 2 (carbon aerogel + activated carbon + conductive agent + binder doped with a transition metal) of the electrode of the high output supercapacitor of the present invention configured as described above 4 shows the capacity (F), leakage current (mA.max), energy density (Wh / kg) and energy power density (kW / l) as compared to the conventional example (active carbon + conductive agent) as shown in FIG. It can be seen that the internal resistance (DS-ESR) is reduced in a state where no difference occurs, as described above, the electrode of the high output supercapacitor of the present invention prevents a decrease in charge density due to the use of a conductive agent for electrical conductivity. In addition, it is possible to improve rapid charge / discharge by preventing electrical resistance (DS-ESR) from increasing by improving electrical conductivity.

Referring to the accompanying drawings, a method of manufacturing the electrode of the high output supercapacitor of the present invention which can improve the charge density and the rapid charge / discharge is as follows.

1 and 2, a method of manufacturing an electrode of the high output supercapacitor of the present invention first prepares a carbon aerogel (S10). When the carbon airgel is prepared, the carbon aerogel is doped with a transition metal to form a carbon aerogel doped with the transition metal (S20). When the transition metal is doped to prepare an active material by mixing the activated carbon and the binder to the carbon metal gel doped with the transition metal (S30). When the active material is prepared, a slurry is prepared by mixing the active material with a binder (S40). When the slurry is prepared, the slurry is applied to a current collector (not shown) (S50) to prepare an electrode of the high output supercapacitor of the present invention.

Hereinafter, the manufacturing process of the electrode of the high output supercapacitor of the present invention will be described in detail.

In preparing the carbon airgel (S10), first, resorcinol and Na ₂ CO _3, which is a catalyst, are mixed in distilled water, and then formaldehyde is injected to prepare a sol (S11). In preparing the sol, resorcinol (1,3-dihydroxybenzene, C ₆ H ₄ (OH) ₂ ) and formaldehyde (HCHO) are prepared so that the molar ratio of R / F is 1: 2. Thus, when the sample is prepared such that the molar ratio of resorcinol: formaldehyde is 1: 2 and the molar ratio of resorcinol: catalyst is 500: 1, 25 to 35 g of distilled water is 20 to 30 g of resorcinol and 0.01 to 0.1 catalyst. After putting g and mixing for about 5 to 20 minutes, formaldehyde is added to 35 ~ 45g 30 minutes to 2 hours to mix to prepare a sol. Here, the catalyst is a basic catalyst Na ₂ CO ₃ is used to polymerize the RF (resorcinol-formaldehyde), the gel particles are small, soft and fractal (ie, the fractal aggregation, that is, carbon particles are connected in a three-dimensional network structure.

When the sol is prepared, the sol is dried in an oven (not shown) at 60 to 90 ° C. for 40 to 50 hours to prepare a wet gel (S12). By drying the sol to produce a wet gel as described above, the mechanical strength of the wet gel is increased, and thus the aerogels that are easily broken can be handled without breakage. When the wet gel is prepared, the solvent contained in the wet gel is substituted with acetone for 20 to 30 hours (S13). That is, the aqueous interconnection of the wet gel is formed by removing the water soluble solvent. That is, the surface tension of the pore wall of the wet gel is minimized so that the shrinkage can be minimized during drying. In addition, the acetone substitution process is maintained by forming the skeleton structure of the wet gel.

When the solvent is substituted with acetone, the wet gel substituted with acetone is dried at a low temperature for 20 to 30 hours at 20 to 30 ° C (S14). That is, through such low temperature drying, the RF aerogel as a whole has small particles, high surface area, high mechanical strength, and can increase the density of the wet gel to increase the electrochemical capacitance. When the low temperature drying is completed, the low temperature dried wet gel is hot dried at 40 to 80 ° C. for 10 to 30 hours to prepare an RF airgel (S15). When the RF airgel is manufactured, the RF airgel is thermally decomposed at 600 to 1000 ° C. in a nitrogen atmosphere to prepare a carbon airgel (S16).

In the process of preparing a carbon airgel doped with a transition metal (S20), the carbon airgel is pulverized to prepare a carbon airgel powder (S21). The transition metal compound is mixed with distilled water to prepare an aqueous transition metal solution (S22). Here, the aqueous transition metal solution is composed of a transition metal compound and distilled water (DI water), the transition metal compound is Co (NO ₃ ) _{2 ·} 6H ₂ O, NH ₄ Ru (NO) (NO ₂ ) ₂ , Mn (NO ₃ ) _{2 ·} 6H ₂ O, VOSO ₄ and LiNO ₃ are used.

When the preparation of the aqueous transition metal solution is completed, the carbon aerogel powder is impregnated with the aqueous transition metal solution (S23). The impregnated carbon airgel powder is dried and calcined at 70 to 80 ° C. for 20 to 30 hours to dope the carbon aerogel powder with a transition metal (S24) to prepare a carbon aerogel powder doped with a transition metal. The microstructure of the carbon aerogel doped with the transition metal thus prepared was measured using a transmission electron microscope (TEM), and the results as shown in FIG. 3 were obtained. 3 shows that the carbon particles form pores in a three-dimensional network structure.

In the process of preparing the active material (S30), first, the ratio of the carbon aerogel doped with the transition metal, the activated carbon and the conductive agent is 50 to 87wt% of the carbon aerogel doped with the transition metal, 5 to 20wt% activated carbon, and the conductive agent 3 Prepare to be ~ 10wt% (S31). Here, the carbon aerogel doped with the transition metal is connected to each other in the form of agglomerated carbon particles to have a three-dimensional network structure to increase the electrical conductivity, and the electroplated metal can be improved to improve the capacitance.

The conductive agent is one of ketchen black and Super P carbon, which improves electrical conductivity with a carbon aerogel doped with a transition metal. Super-P carbon is a material in which molecular sieve materials such as carbon molecular sieve are dispersed in a polymer matrix, and is being developed for gas separation applications such as nitrogen production from air as an alternative to existing polymer membranes. When 50 to 87 wt% of carbon aerogels doped with transition metal, 5 to 20 wt% of activated carbon, and 3 to 10 wt% of conductive agent are prepared, these are first mixed (S32). When the primary mixing is completed, the mixed state is confirmed and then mixed for a predetermined time to prepare an active material (S33).

In addition, in the process of preparing the slurry (S40), the binder is mixed with the active material (S41). Here, one of the polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC) and stylen-buthylene-rubber (SBR) is used as the binder to be evenly mixed with the active material. When the binder is mixed with the active material, the slurry is prepared by aging for 24 to 48 hours (S42). That is, when the binder is mixed with the active material, the slurry is aged for 24 to 48 hours to improve the rheology of the slurry and to remove bubbles. To prepare. When the slurry is prepared, it is applied (S50) to the surface of the current collector (not shown) to prepare the electrode of the high output super capacitor of the present invention.

The electrode of the high output supercapacitor of the present invention manufactured by the above manufacturing method is capable of adding a small amount of a conductive agent that can improve electrical conductivity and reduce capacitance by using a carbon aerogel doped with a transition metal as an active material. do. As a result, the electrical conductivity is also improved, and thus, as shown in FIG. 3, the first and second embodiments of the present invention have improved output density and reduced equivalent series resistance (DC-ESR). In addition, as the result of impedance measurement, the equivalent series resistance is reduced, and the charge transfer speed is increased at the interface between the electrode and the electrolyte, and the current reaches the steady state quickly, thereby providing the advantage of rapid charge / discharge.

The electrode of the high output supercapacitor of the present invention and a manufacturing method thereof may be applied to a supercapacitor applied to a large-capacity energy storage device of a smart grid.

Claims (12)

50 to 87 wt% of carbon aerogels doped with transition metal, 5 to 20 wt% of activated carbon, 3 to 10 wt% of conductive agent, and 5 to 20 wt% of binder,
The carbon aerogel doped with the transition metal has a three-dimensional network (3D-network), characterized in that the electrode of the high power super capacitor. delete The method of claim 1, wherein the transition metal-doped carbon aerogel is doped with one of cobalt (Co), ruthenium (Ru), manganese (Mn), vanadium (V), tin (Sn) and lithium (Li). Super capacitor electrode, characterized in that the. The method of claim 1, wherein the transition metal has a precursor shape,
The diameter of the precursor is a super capacitor electrode, characterized in that the fine particles 20 to 200nm. The electrode of claim 1, wherein the conductive agent is one of carbon black and super-p carbon. The electrode of claim 1, wherein the binder is one of PTFE (polytetrafluoroethylene), CMC (carboxymethylcellulose) and SBR (stylen-buthylene-rubber). Preparing a carbon airgel;
Preparing a carbon aerogel doped with a transition metal by doping a transition metal to the carbon aerogel when the carbon aerogel is prepared;
Preparing an active material by mixing activated carbon and a conductive agent in a carbon airgel doped with a transition metal when the transition metal is doped;
Preparing the slurry by mixing the active material with a binder when the active material is prepared:
When the slurry is prepared, the electrode manufacturing method of a high output super capacitor, characterized in that consisting of the process of applying the slurry to the current collector. The method of claim 7, wherein the preparing of the carbon airgel comprises: preparing sol by injecting formaldehyde after mixing resorcinol and Na ₂ CO _3, which is a catalyst, in distilled water;
When the sol is prepared, drying the sol at 60 to 90 ° C. for 40 to 50 hours in an oven to prepare a wet gel;
When the wet gel is prepared, replacing the solvent contained in the wet gel with acetone for 20 to 30 hours;
Low temperature drying of the wet gel substituted with acetone when the solvent is substituted with acetone for 10 to 30 hours at 20 to 30 ° C;
When the low temperature drying is complete, the low-temperature drying of the wet gel at high temperature for 10 to 30 hours at 40 ~ 80 ℃ to prepare a RF (resorcinol-formaldehyde) airgel;
When the RF airgel is manufactured, a method of manufacturing an electrode of a high output super capacitor, characterized in that the process of producing a carbon airgel by thermal decomposition of the RF airgel at 600 ~ 1000 ℃ in a nitrogen atmosphere. The method of claim 7, wherein the preparing of the transition metal-doped carbon airgel comprises: preparing carbon airgel powder by pulverizing the carbon airgel;
Mixing the transition metal compound with distilled water to prepare an aqueous transition metal solution;
Impregnating the carbon metal airgel powder with the transition metal aqueous solution;
The method of claim 1, wherein the impregnated carbon airgel powder is dried and calcined at 70 to 80 ° C. for 20 to 30 hours to dope the transition metal into the carbon airgel powder. The method of claim 9, wherein the transition metal aqueous solution is made of a transition metal compound and distilled water in the process of preparing the transition metal aqueous solution,
The transition metal compound is one of Co (NO ₃ ) _{2 ·} 6H ₂ O, NH ₄ Ru (NO) (NO ₂ ) ₂ , Mn (NO ₃ ) _{2 ·} 6H ₂ O, VOSO ₄ and LiNO ₃ Electrode manufacturing method of high power super capacitor. According to claim 7, wherein the process of preparing the active material is a carbon aerogel doped with a transition metal, the carbon aerogel doped with a transition metal doped each of the carbon aerogel doped with a transition metal 50 ~ 87wt%, activated carbon 5 ~ 20wt%, and Method of manufacturing an electrode of a high output super capacitor, characterized in that the mixture is prepared so as to be 3 ~ 10wt%. The method of claim 7, wherein the preparing of the slurry comprises: mixing a binder with an active material;
When the binder is mixed with the active material, the electrode manufacturing method of the high output super capacitor, characterized in that consisting of a process for producing a slurry by aging for 24 to 48 hours.

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