KR20140095844A - nano carbon materials having multiple hydrogen bonding motifs for electrode in supercapacitors - Google Patents

Abstract

The present invention relates to a carbon nanomaterial electrode having a higher-order structure by multiple hydrogen bonds for being used as an electrode of a supercapacitor. The technical summary of the carbon nanomaterial electrode having a higher-order structure by multiple hydrogen bonds for being used as an electrode of a supercapacitor is that an electrode of a supercapacitor is made of a carbon nanomaterial, the carbon nanomaterial forms an electrode material which can form multiple hydrogen bonds between the carbon nanomaterials by introducing a functional group capable of multiple hydrogen bonds into the surface or end thereof, and the carbon nanocarbon material is used as the electrode. Accordingly, performance of the supercapacitor can be improved due to excellent conductivity and specific capacitance of the electrode by introducing a functional group capable of forming at least three multiple hydrogen bonds in the conductive carbon nanomaterial to form carbon nanomaterial paste having a higher-order structure by multiple hydrogen bonds without using a dispersing agent or the like and using the carbon nanomaterial paste as the electrode of the supercapacitor while using the carbon nanomaterial having high electrical conductivity as the electrode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a carbon nanomaterial having a high-order structure by multi-hydrogen bonding used as a supercapacitor electrode,

The present invention relates to a carbon nanomaterial electrode having a high-order structure by multiple hydrogen bonds used as an ultra-high-capacity capacitor electrode, and more particularly, to a carbon nanomaterial electrode having excellent electrical conductivity as an electrode, A multi-hydrogen bond is formed by forming a carbon nanomaterial paste having a higher-order structure by multi-hydrogen bonding by introducing a functional group capable of forming three or more multi-hydrogen bonds, and using this as a super high capacity capacitor electrode. To a carbon nanomaterial electrode having a higher order structure.

In general, a super-high-capacity capacitor utilizes electrostatic characteristics, so that the number of charge-discharge cycles is almost infinite as compared with a battery using an electrochemical reaction, and it can be used semi-permanently. It is more than a dozen times the battery.

The instantaneous power of such a high capacity capacitor is applied to the fuel cell vehicle technology to improve the acceleration performance of the vehicle, and it is extremely durable and reliable because it does not use the electrochemical reaction.

That is, supercapacitors are used as auxiliary energy sources in conjunction with the primary energy supply battery in systems that are used independently as low-capacity energy storage devices or require instantaneous energy supply. These characteristics can be expected to improve the overall efficiency of the vehicle system and extend the life of the energy storage system.

Due to the characteristics of such ultra-high-capacity capacitors, which can not be realized with conventional batteries, the application fields are gradually expanding to automotive, general industrial, space / military, and the like.

As a mechanism for storing energy, a larger capacitance can be obtained as the capacitor has a larger specific surface area and a higher dielectric constant. To satisfy these conditions, many studies using active carbon powder, activated carbon fiber, aerogel carbon, and carbon black have been published. Of these, activated carbon is one of the materials that has been used for this purpose because of its good electrical conductivity, large specific surface area, easy manufacturing and low cost. In the case of metal oxide or conductive polymer electrode material, it is possible to fabricate ultra-high capacity capacitor with high output characteristic, but it has disadvantage that capacity at charge / discharge is rapidly decreased at a rapid charging / discharging rate. Research is underway to improve discharge characteristics.

Capacitance and discharge rate of ultra-high-capacity capacitors using carbon-based electrodes can vary greatly depending on the physicochemical properties of the carbonaceous material, the type of electrolyte, and the charging and discharging conditions. Especially, the physicochemical properties of the carbon-based electrode material have a great influence on the electrochemical behavior of the ultra-high-capacity capacitor.

Conventional ultra-high capacity capacitor electrode manufacturing technology has been mainly focused on a method of coating a collector with slurry of a carbon-based active material and a binder. In this case, since the amount of the active material contacting the current collector is small, the storage capacity is not large and the electrode resistance is increased.

Recently, an electric double layer capacitor (EDLC), which is a type of ultra high capacity capacitor that has begun to be used as a substitute for a battery in an electronic part, has been applied to general industrial applications by incorporating new materials and technologies.

An ultra-high-capacity capacitor using a carbon-based electrode is an electric double layer capacitor expressed by an electric double layer mechanism, which uses an electric double layer formed on the back surface of the both using a carbon-based material and an electrolytic solution having a large surface area of activated carbon for charge storage. That is, electric double layer capacitors are environmentally friendly because they use carbon as a main material as well as long lifetime and high power.

Since the capacitance of such an electric double layer capacitor is determined by the surface area of the electrode and the electric double layer per unit area of the electrode, a carbon electrode having a large filling density and specific surface area should be used for improving the capacitance density.

As such, the electric double layer capacitor uses an environmentally friendly carbon material together with excellent stability of the electrode material itself. Carbon electrode materials include activated carbon powder (ACP), carbon nanotube (CNT), graphite, graphite, vapor grown carbon fiber (VGCF), carbon aerogels, , Carbon nanofiber (CNF) produced by carbonizing a polymer such as polyacrylonitrile (PAN) or polyvinylidene fluoride (PVdF), activated carbon nanofibers (CNF) (ACNF; Activated Carbon Nano Fiber). Carbon black (CB) or the like may be added to impart conductivity in addition to the carbon material.

The electric double layer capacitor is composed of a current collector, an electrode, an electrolyte and a separator. Electrolytes are filled between two electrodes electrically separated from each other due to the separator. The current collector effectively charges or discharges the electrode .

The active carbon electrode used as an electrode material of such an electric double layer capacitor is a porous material composed of micropores and has a large specific surface area. When (-) is attached to the activated carbon electrode, (+) ions dissociated from the electrolyte are adsorbed on the activated carbon electrode And enters the pores to form a (+) layer, which charges the charge while forming an electric double layer with a negative (-) layer formed at the interface of the activated carbon electrode.

The electric capacity of the electric double layer capacitor depends greatly on the structure and physical properties of the activated carbon electrode. The required characteristics include a large specific surface area, a small internal resistance of the material itself, and a high density of carbon material.

In order to solve such a problem, studies have been made on the use of carbon nanomaterials such as carbon nanotubes and graphene as the ultra-high capacity capacitor electrodes.

Carbon nanotubes have electrical resistivity of 10 ^-4 Ωcm and have electrical conductivity comparable to that of metal. Their surface area is more than 1000 times higher than that of bulk materials, and they have been actively studied in recent years for its manufacturing, application and application fields. In particular, carbon nanotubes have characteristics of electrical conductors such as metals and semiconductors that are not electrically conductive depending on their shapes and sizes. Therefore, carbon nanotubes are very stable not only in various electronic circuit fields but also chemically and mechanically, The field of application is expected to be very diverse. The other carbon nanomaterials graphene quantum Hall effect, high carrier mobility at room temperature is also ^{(~ 10,000 cm 2 / Vs)} , 1 large specific surface area (2630cm ² / g), ² excellent light transmittance (~ 97.7%), ³ High mechanical properties (~ 1 TPa) ⁴ and excellent thermal conductivity (3000-5000 W / mK) ⁵ . Since nano-carbon materials such as carbon nanotubes, graphene, carbon fiber, and fullerene exhibit electrochemical characteristics due to their excellent electrical conductivity and wide specific surface area properties, they can be used not only as supercapacitors but also as dye- It is expected to be used as various electrochemical electrodes such as fuel cell.

Activated carbon nanofibers (ACNF) having a high specific surface area of about 1500 to 3000 m 2 / g can be obtained by base activating polyacrylonitrile (PAN) as an example of an electric double layer capacitor electrode. However, The resistance (ESR) is somewhat higher and the capacitance is lower than that of the electrode made of activated carbon powder (ACP). When the density of the electrode active material is low, the resistance generally increases and the storage capacity decreases.

On the other hand, in order to improve the contact characteristics between the electrode material and the current collector or the electrode material, a binder and a dispersing agent are used. In this case, the content of the binder and the dispersing agent used is such that the physical property of the electrode material can be maintained Because most of the binder and dispersant materials are not conductive, and therefore, if the added amount is large, there is a fear that the physical properties of the electrode material may be deteriorated by increasing the electrode resistance. In addition, by introducing excessive functional groups on the surface or end of the carbon nanomaterial, it is possible to secure the high dispersibility of the carbon nanomaterial and realize a pseudocapacitor characteristic by the functional group. However, in this case, the conductivity of the electrode material itself decreases, .

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a method of manufacturing a conductive carbon nanomaterial using a carbon nanomaterial excellent in electrical conductivity as an electrode, A high-density carbon nanomaterial paste having a higher-order structure by introducing a functional group having a higher-order structure by introducing a functional group and forming a high- And to provide a material electrode.

According to an aspect of the present invention, there is provided an electrode of an ultra-high capacity capacitor, wherein the electrode is formed of a carbon nanomaterial, and the carbon nanomaterial is introduced with a minimum amount of functional groups capable of multi- The present invention relates to a carbon nano-material electrode having a high-order structure by multi-hydrogen bonding, which is used as an ultra-high-capacity capacitor electrode which forms a highly conductive electrode material in which multiple hydrogen bonds are formed between carbon nanomaterials.

It is preferable that the carbon nanomaterial is at least one of a single-walled carbon nanotube, a multi-walled carbon nanotube, a graphene, a carbon fiber, a carbon black, a graphite, and an activated carbon.

The carbon nanomaterial is preferably formed as an electrode by being complexed with at least one metal oxide material selected from the group consisting of SnO ₂ , Co ₃ O ₄ , RuO ₂ , TiO ₂ , MnO ₂ , Mn ₃ O ₄ , ZnO and Fe ₃ O ₄ .

The carbon nanomaterial is preferably formed in a paste form.

The functional group capable of multiple hydrogen bonding is selected from the group consisting of 2-ureido-4 [1 H] pyrimidinone derivatives, 2-ureido-4 [H] pyrimidinol, 4 [1H] pyrimidinol derivatives, 2-uriedo-4-pyrimidone derivatives, diacylpyrimidine derivatives, ureidoacylpyrimidine derivatives, acetylaminotri An acetylaminotriazine derivative, a ureidotriazine derivative, a 2,6-di (acetylamino) -4-pyridyl derivative, a thymine derivative, , 2-aminobenzimidazole derivatives, 2,7-diamino-1,8-naphthyridine derivatives, di (hexanoylamino) pyrimidines (hexanoylamino) pyrimidine derivatives, and 2-butylureido-4-acetylaminopyridine derivatives.

Accordingly, a carbon nanomaterial excellent in electric conductivity is used as the electrode, and a functional group capable of forming three or more multiple hydrogen bonds in the conductive carbon nanomaterial is introduced into the conductive carbon nanomaterial without using a dispersant, By forming a nanocomposite paste and using it as an electrode of an ultra high capacity capacitor, the conductivity and non-storage capacity of the electrode are good and the performance of the ultra high capacity capacitor is improved.

According to the present invention, a functional carbon group capable of forming three or more multi-hydrogen bonds can be introduced into a conductive carbon nanomaterial without using a dispersant to form a highly conductive carbon nanomaterial paste having a high-order structure by multiple hydrogen bonding By printing on a substrate using printing equipment and using it as an electrode of an ultra-high-capacity capacitor, the conductivity and non-storage capacity of the electrode are good and the performance of the ultra-high capacity capacitor is improved.

FIG. 1 is a schematic view showing multiple hydrogen bonding introduced into a carbon nanomaterial according to an embodiment of the present invention,
FIG. 2 is a photograph showing a paste formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to the first embodiment of the present invention,
3 is a scanning electron microscope (SEM) image of a cross section of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to the first embodiment of the present invention,
FIG. 4 is a graph showing a current change according to an applied voltage according to a scan speed of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to the first embodiment of the present invention,
FIG. 5 is a graph showing electrochemical impedance measured values of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to the first embodiment of the present invention,
6 is a graph showing a change in specific capacitance according to scan speed of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to each embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic view illustrating multiple hydrogen bonding introduced into a carbon nanomaterial according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a multi- FIG. 3 is a scanning electron micrograph of a cross section of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to the first embodiment of the present invention, and FIG. 4 is a cross- FIG. 5 is a graph showing a change in current according to an applied voltage according to a scan speed of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to a first embodiment of the present invention. FIG. 6 is a graph showing an electrochemical impedance measurement value of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding. FIG. FIG. 3 is a graph showing a change in specific capacitance according to scan speed of an electrode formed using a high-order structure carbon nanomaterial by multiple hydrogen bonding according to an example.

As shown in the figure, a carbon nanomaterial electrode having a high-order structure by multiple hydrogen bonding used as an ultra-high capacity capacitor electrode is an electrode of an ultra-high capacity capacitor, wherein the electrode is formed of a carbon nanomaterial, An electrode material in which multiple hydrogen bonds are formed between carbon nanomaterials is formed by introducing a functional group capable of multiple hydrogen bonding at the surface or end and is used as an ultra high capacity capacitor electrode.

In this case, the multiple hydrogen bond is composed of a hydrogen bond donor (D), a hydrogen bond acceptor (A), and an ionic hydrogen bond acceptor (D +). When the arrangement of D, D + and A is tritium bond, ADA- AAA-DDD +, AAA-DDD +, and AAA-DDD +, and the fourteen deuterium bonds are one of ADAD-DAA, AAA-DDD and AAA- DDD + It is preferred to introduce at least one functional group into the cationic AAAA-DDD + structure.

The functional group capable of hydrogen bonding is preferably a 2-ureido-4 [1 H] pyrimidinone derivative, a 2-ureido-4 [H] pyrimidinol (4-ureido-4 Pyrimidinol derivatives, 2-uriedo-4-pyrimidone derivatives, diacylpyrimidine derivatives, ureidoacylpyrimidine derivatives, acetylaminotriazine derivatives, acetylaminotriazine derivatives, ureidotriazine derivatives, 2,6-di (acetylamino) -4-pyridyl derivatives, thymine derivatives, 2-aminobenzimidazole derivatives, 2,7-diamino-1,8-naphthyridine derivatives, di (hexanoylamino) pyrimidine di (hexanoylamino) pyrimidine derivatives, and 2-butylureido-4-acetylaminopyridine derivatives.

≪ Embodiment 1 >

A first embodiment of the present invention relates to a method of preparing a conductive paste by introducing a functional group capable of forming a quadruple hydrogen bond to carbon nanotubes and graphene and using the carbon nanotube as an electrode of a supercapacitor.

The structure of the quadrivalent hydrogen bonding functional group introduced into the carbon nanomaterial is schematically shown in Fig.

First, carbon nanotubes having carboxyl groups introduced therein and oxide graphene were dispersed in a solvent of dimethylformamide at a concentration of 100 mg / L, and then toluene diisocyanate and amino-4-hydroxy-6-methylpyrimidine (2-ureido-4 [H] pyrimidine (4-hydroxy-6-methyl-pyrimidine) having a quaternary hydrogen bond in such a manner that the amino- (2-ureido-4 [1H] pyrimidinone) was introduced.

As shown in FIG. 2, the paste was prepared by using a dimethylformamide solvent with supramolecular carbon nanotube-graphene having multiple hydrogen bonds prepared in the above, by simple stirring without the need for other additives. The carbon nanotube-graphene paste having a weight% or more can be easily produced by simple stirring.

The carbon nanotube-graphene paste prepared above was applied to a metal foil using a bar coater, and the residual solvent was removed at 200 ° C.

3 is a cross-sectional view of the carbon nanotube-graphene hybrid electrode prepared above.

In FIG. 3, when carbon nanotubes and graphene are hybridized, carbon nanotubes are present between graphene and graphene to prevent restacking of graphene and form mesopores. Is increased.

And the electrochemical characteristics of the electrodes were platinum (Pt), saturated calomel, and nanocarbon electrodes. The electrolyte was measured using a 1 M sulfuric acid solution and the electrochemical impedance was measured from 100 kHz to 100 mHz.

FIG. 4 is a graph showing a current value according to an applied voltage according to a scan speed. As shown in FIG. 4, a square-shaped current-voltage cycle shape appears in a typical electric double layer capacitor of a supercapacitor, The redox reaction peak appears in the middle.

6, when the carbon nanotubes and the graphene are hybridized, they exhibit an excellent capacity of more than 200 F / g at a scan rate of 10 mV / s. In particular, it was confirmed that a capacity of 90% or more was maintained even at a high-speed scan of 1000 mV / s.

5 is an impedance spectrum showing the interface resistance at the interface between the electrode and the electrolyte. The graph shows that the interface resistance shows a small value of less than 1 ohms (ohms) and the graph shows a nearly vertical rise in a small frequency region. Indicating that the graphene hybrid electrode exhibits excellent storage behavior.

≪ Embodiment 2 >

In the second embodiment of the present invention, a functional group capable of forming a _quadruple hydrogen bond is introduced into the carbon nanotube and graphene in the first embodiment, and 5 ml of 0.02 M KMnO _{4 and} 5 ml of 0.03 M MnSO ₄ are sequentially added (MnO ₂ ) nanoparticles were added in the form of stirring for about 20 minutes, which is different from the first embodiment.

A carbon nanotube-graphene-manganese oxide composite paste was prepared in a similar manner to the first embodiment.

The prepared carbon nanotube-graphene-manganese oxide composite paste was formed into an electrode on a copper foil using a bar coater, and the residual solvent was removed at 200 ° C.

As a result of calculation of the non-storage capacity, as shown in FIG. 6, the capacity is more than 300 F / g at a scan rate of 10 mV / s, and more than 85% is maintained even at a high speed scan of 1000 mV / s Respectively.

≪ Third Embodiment >

In the third embodiment of the present invention, a functional group capable of forming a quadrivalent hydrogen bond is introduced using only carbon nanotubes, a paste is formed and then an electrode is formed. The remaining process is the same as the first embodiment Electrode.

As a result of calculation of the non-storage capacity, as shown in FIG. 6, the non-storage capacity showed a smaller non-storage capacity value than the carbon nanotube-graphene composite (first embodiment). However, even when using carbon nanotubes alone, it was confirmed that a capacity of 85% or more was maintained even at a high-speed scan of 1000 mV / s.

<Fourth Embodiment>

In the fourth embodiment of the present invention, a functional group capable of forming a quadruple hydrogen bond is introduced using only graphene, and an electrode is formed after a paste is formed. The remaining process is the same as in the first embodiment, .

As a result of calculation of the non-storage capacity, as shown in FIG. 6, the non-storage capacity showed a smaller non-storage capacity value than the carbon nanotube-graphene composite (first embodiment). However, even when using graphene alone, it was confirmed that a capacity of 85% or more was maintained even at a high-speed scan of 1000 mV / s.

As described above, it is possible to paste various carbon nanomaterials by using multiple hydrogen bonds, and it is possible to realize supercapacitors of superior performance as compared with the case of using a single material by composing various carbon nanomaterials. It is possible to form a highly conductive carbon nanomaterial electrode for realizing a supercapacitor superhigh capacity super capacitor by forming an electrode and it is advantageous from the viewpoint of commercialization and it is possible to form paste of carbon nanomaterial without loss of conductivity of carbon nanomaterial. .

It can be seen that the performance of the pseudocapacitor is improved by inducing a redox reaction by a multi-hydrogen bonding functional group and meso pore formation by multiple hydrogen bonding functional groups is easy.

Claims (5)

In an electrode of an ultra-high capacity capacitor,
The electrode is formed of a carbon nanomaterial,
Wherein the carbon nanomaterial is formed by forming a multi-hydrogen bonding electrode material between carbon nanomaterials by introducing a functional group capable of forming multiple hydrogen bonds on the surface or end, and using the electrode material as an electrode. A carbon nanomaterial electrode having a higher order structure by hydrogen bonding. The super high capacity capacitor electrode according to claim 1, wherein the carbon nanomaterial is at least one of a single wall carbon nanotube, a multi wall carbon nanotube, a graphene, a carbon fiber, a carbon black, a graphite, and an activated carbon. A carbon nanomaterial electrode having a higher order structure by multiple hydrogen bonds. The carbon nanomaterial according to claim 1, wherein the carbon nanomaterial is complexed with at least one metal oxide material selected from the group consisting of SnO ₂ , Co ₃ O ₄ , RuO ₂ , TiO ₂ , MnO ₂ , Mn ₃ O ₄ , ZnO, and Fe ₃ O ₄ , Carbon nanomaterial electrode having a higher order structure by multiple hydrogen bonding used as an ultra-high-capacity capacitor electrode. The carbon nanomaterial electrode according to claim 1, wherein the carbon nanomaterial is formed in a paste form. The carbon nanomaterial has a higher order structure by multi-hydrogen bonding used as an ultra-high capacity capacitor electrode. The method according to any one of claims 1 to 4, wherein the functional group capable of multiple hydrogen bonding is selected from the group consisting of 2-ureido-4 [1 H] pyrimidinone derivatives, 2- 4-pyrimidinol derivatives, 2-urido-4-pyrimidone derivatives, diacylpyrimidine derivatives, 4-pyrimidinol derivatives, Derivatives thereof, ureidoacylpyrimidine derivatives, acetylaminotriazine derivatives, ureidotriazine derivatives, 2,6-di (acetylamino) -4-pyridyl (2,6-di (acetylamino) -4-pyridyl) derivatives, thymine derivatives, 2-aminobenzimidazole derivatives, 2,7-diamino-1 , 8-naphthyridine derivatives, di (hexanoylamino) pyrimidine derivatives, and 2-butylureido-4-acetylaminopyridine derivatives. By multiple hydrogen bonds that are used as supercapacitors, characterized in that the electrodes by a carbon nano-material electrode having a high-order structure.

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