KR101912294B1 - Method for manufacturing graphene, dispersed composite of graphene and method for manufacturing dispersed composite of graphene - Google Patents

Abstract

The present invention relates to a graphene production method, a graphene dispersion composition, and a production method thereof, comprising the steps of: preparing a graphite intercalation compound by heat treating natural graphite and a mixture of alkali metals; Mixing the graphite intercalation compound with a pyridine-based solvent; And a step of sonicating the mixed graphite intercalation compound and the pyridine-based solvent, a graphene dispersion composition containing the graphene dispersion composition, and a method for producing the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a graphene dispersion composition, a graphene dispersion composition, and a method for producing the graphene dispersion composition,

The present invention relates to a graphene manufacturing method, a graphene dispersion composition, and a manufacturing method thereof.

Energy, Economy, and Environment, collectively referred to as E3, are the challenges that future humans must address in order to live a higher level of life. Especially, in the field of IT / BT / ET in the country-based business, graphene, which is superior in electrical, thermal and mechanical properties, is regarded as a core technology in the field of application technology and is recognized as a next generation core device.

The excellent electrical properties of graphene are expected to be used as a key element in display, electric, electronic and bio fields. In particular, the market for semiconductor devices has already surpassed 100 trillion won in 2007. Moreover, the total market size of RF electronic devices is growing at an average annual rate of 6.2% (2007-2011), and is expected to increase from KRW 9 trillion in 2007 to KRW 12 trillion in 2011. The mechanical and physicochemical properties of graphene can be applied to secondary battery and super capacitor applications. It can be used for switching center / base station power supply, pollution-free vehicles (fuel cell automobile, electric vehicle, hybrid car), high power, And it is expected to expand to major applications in the future.

Graphene can be produced by methods such as mechanical exfoliation, epitaxial growth, chemical vapor deposition, graphite oxide-reduction, and graphite intercalation compound . ≪ / RTI >

The mechanical stripping method can produce high quality graphene by a simple manufacturing process, but the very low yield of the graphene produced and the size of the uneven graphene sheet are not suitable for commercial application.

The graphene produced by epitaxial and chemical vapor deposition can synthesize graphene sheets which are superior in terms of mechanical, thermal and electrical properties compared with the graphite intercalation compound produced by the extreme redox process of graphite, High manufacturing costs due to process and low yield due to narrow reactor space still remain as a challenge. In particular, in the case of high-quality graphene-based composites based on liquid-phase processes, strong cohesion between graphenes occurs due to low surface charge of graphene. As a result, very low dispersion characteristics are exhibited in the selected solvent, and the mechanical and electrical properties of the fused composite material are deteriorated, which has considerable obstacles to practical application and academic research.

Many research papers have been published on improvement of dispersion properties through surface modification of graphene. In general, surface modification of graphene can be achieved by introducing various functional groups related to oxygen (Oxygen) and nitrogen (Nitrogen) on the surface of graphene through chemical acid treatment or ultrasonic wave, It can cause considerable damage to the structure. Therefore, it greatly affects the electrical, thermal, and physical properties.

In addition, in the approach using the surfactant and the block copolymer, the hydrophobic moiety is physically adsorbed on the surface of the graphene, and the hydrophilic moiety forms a dipole toward the solvent to disperse the stable graphene. For example, there are research results such as SDS (sodium dodecyl sulfate), Tween 20, Triton X-100, NaDDS (sodium dodecyl sulfate) and OTAB (octadecyltrimethylammonium bromide). However, surface modification using a short chain surfactant may be undesirable for surface modification with surfactants due to the electrical conductivity which is significantly lowered during conductive film formation than the matrix polymer. In addition, this approach significantly degrades the physical properties of the graphene / polymer composite application and poses a major challenge to long-term stability due to the adsorption of the surfactant, the desorption equilibrium and the strong attraction of the graphene. Block copolymers can modify the surface of graphene with amphoteric properties that have both hydrophobic / hydrophilic properties. For example, research has been conducted to disperse polystyrene-polyacrylic acid (PS-PAA) and graphene, which are block copolymers. [J. Am. Chem. Soc., 125, 5650 (2003)] In addition, although the dispersion characteristics were improved by grafting a vinyl polymer to carbon nanotubes by using ultrasonic waves together with strong acids in the carbon nanotubes, serious property deterioration was caused. [Patent No. 689866]

 Other biopolymers have been studied for modification of graphene surface using p-interactions, hydrophobic interactions, van der Waals forces, ionic bonds by amine functional groups, and hydrogen bonds, but their commercial viability is largely limited There is.

Therefore, there is a continuing need for studies to improve the dispersion characteristics without producing high-yield, zero-graphene graphene and without deteriorating the physical properties of graphene.

An embodiment of the present invention is to provide a method for producing a defect-free graphene which can produce a graphene of a zero-defect at a high yield.

Another embodiment of the present invention is to provide a dispersion composition of non-defective graphene in which non-defective graphene is stably and uniformly dispersed in various solvents, and a method of manufacturing the same.

One embodiment of the present invention is a method for producing graphite, comprising: heat treating a mixture of natural graphite and an alkali metal to produce a graphite intercalation compound; Mixing the graphite intercalation compound with a pyridine-based solvent; And ultrasonically treating the mixed graphite intercalation compound and the pyridine-based solvent.

The step of heat-treating the mixture of natural graphite and an alkali metal to produce an intercalation compound of graphite may be performed at a temperature of 70 ° C or higher and 200 ° C or lower.

The step of heat treating the mixture of natural graphite and alkali metal to produce an intercalation compound of graphite may have a heat treatment time of 30 minutes or more and 90 minutes or less.

The step of heat treating the natural graphite and the mixture of alkali metals to prepare the graphite intercalation compound may be carried out under vacuum conditions of more than 10 ^-5 Torr and less than 10 ^-2 Torr.

The pyridine-based solvent may include pyridine, a pyridinium compound, or a combination thereof.

The graphene manufacturing method includes: mixing the graphite intercalation compound with a pyridine-based solvent; And then allowing the mixed graphite intercalation compound and the pyridine-based solvent to be left to expand the graphite interlayer distance of the graphite intercalation compound.

The step of allowing the mixed graphite intercalation compound and the pyridine-based solvent to expand the graphite interlayer distance of the graphite intercalation compound is carried out at a temperature of -41.6 DEG C or higher and a temperature of 0 DEG C or lower for 3 hours or longer and 48 hours or shorter It can be left standing for hours.

Ultrasonically treating the mixed graphite intercalation compound and the pyridine-based solvent,

0 < 0 > C and 10 < 0 > C, 10 minutes, and 24 hours or less.

Wherein the molar ratio of natural graphite and alkali metal in the mixture (natural graphite: alkali metal) is 1: 0.1 or more, and the ratio of the natural graphite to the alkali metal in the mixture is 1: 0.1 or more; 1: 0.2 or less.

The graphene manufacturing method comprises: ultrasonifying the mixed graphite intercalation compound and the pyridine-based solvent; Thereafter, the ultrasonic treated graphite intercalation compound and the pyridine-based solvent mixture may be dried to obtain a defect-free graphene.

Another embodiment of the present invention includes the steps of mixing graphene, a graphene surface modifier, and a dispersion solvent prepared in one embodiment of the present invention; And applying a physical force to the mixed mixture. ≪ IMAGE >

And applying a physical force to the mixed mixture, whereby the surface modifier is physically or chemically attached to the graphene surface.

And applying a physical force to the mixed mixture, whereby the surface modifier is attached to the graphene surface via noncovalent interaction.

Applying a physical force to the mixed mixture may be performed through stirring, ultrasonic treatment, or a combination thereof.

The surface modifier may be 3,4,9,10-perylentetracarbonsauredianhydride (PTCDA), thiophene-diketopyrrolopyrrole (TDPP) , Poly (9,9-di- (N, N-dimethylaminopropylfluorenyl-2,7-diyl), PFDMA) , Poly (p-phenylenevinylene), poly (3-hexyl-thiophene), poly

Cyclopenta [2,1-b (3,4-b '] dithiophene) -alt-4,7,7 (2-ethylhexyl) , 1,3-benzothiadiazole)] (Poly [2,6- (4,4-bis- (2-ethylhexyl) -4H-cyclopenta [ (4 ', 7', 7 ', 7 ") -7-benzothiadiazole], PCPDTBT), poly [N-9'-heptadecanyl] -2,7- (4'-heptadecanyl-2,7-carbazole-alt-5,5- (4 ', 3'- , 7'-di-2-thienyl-2 ', 1', 3'-benzothiadiazole)], PCDTBT), poly [9- (1-octylnonyl) -9H-carbazole- 2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophendi] (Poly [[9- (1-octylnonyl) -9H-carbazole -2,7-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl], PCDTBT), poly (4,4-dioctyldicyano 3,2-b: 2'3'-d) silole) -2,6-diyl-alt- (2,1,3-benzothiadiazol- 2,6-diyl-alt- (2,1,3-benzothiadiazole) -4,7-diyl, PSBTBT), poly [1- (6- {4,8-bis [(2- 3,4-b] thiophen-2-yl} -3-fluoro-4-methylthieno [3,4- b] Bis [(2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4,5- 2-yl] -3-fluoro-4-methylthieno [3,4-b] thiophen-2-yl) -1-octanone], PBDTTT-CF), naphthalene diimide (NDI) , Perylene Diimide (PDI), Nafion (R), Carbazole, Thiazole, Selenophene, Fused thiophene, Naphthothiadiazole, Phenothiazine, Quinoxaline, or a combination thereof.

The dispersion solvent may be at least one selected from the group consisting of pyridine, toluene, dimethylsulfoxide (DMSO), isopropyl alcohol (IPA), acetone, ethanol, methanol, Water, or a combination thereof.

According to another embodiment of the present invention, graphene produced in one embodiment of the present invention is used. And a surface modifier that is physically or chemically attached to the graphene; And a dispersion solvent.

The surface modifier may be 3,4,9,10-perylentetracarbonsauredianhydride (PTCDA), thiophene-diketopyrrolopyrrole (TDPP) , Poly (9,9-di- (N, N-dimethylaminopropylfluorenyl-2,7-diyl), PFDMA) , Poly (p-phenylenevinylene), poly (3-hexyl-thiophene), poly [2,6- (4,4- Cyclopenta [2,1-b: 3,4-b '] dithiophene) alt-4,7 (2,1,3-benzothiadiazol)] (2,1-b, 3,4-b '] dithiophene) -but-4,7 (2,1- 3-benzothiadiazole)], PCPDTBT), poly [N-9'-heptadecanyl] -2,7-carbazole-alt-5,5- (4 ', 7'- ', 1', 3'-benzothiadiazole) (Poly [N-9'-heptadecanyl-2,7-carbazole-alt-5,5- (4 ', 7'-di- ', 1', 3'-benzothiadiazole)], PCDTBT), poly [9- (1-octylnonyl) -9H- -2,7-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophendiyl] (Poly [[9- 2,7-diyl-2,5-thiophenediyl-4,7-diyl-2,5-thiophenediyl], PCDTBT), poly (4, (3,2-b: 2'3'-d) silole) -2,6-diyl-alt- (2,1,3-benzothiadiazol- (Poly (4,4-dioctyldithieno (3,2-b: 2 ', 3'-d) silole) -2,6-diyl-6- (2,1,3-benzothiadiazole) , PSBTBT), poly [1- (6- {4,8-bis [(2-ethylhexyl) oxy] -6-methylbenzo [ Yl} -3-fluoro-4-methylthieno [3,4-b] thiophen- (2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4,5- b '] dithiophen-2-yl} -3-fluoro-4- methylthieno [3,4- b] thiophen- (PDI), Nafion (R), Carbazole, Thiazole (PDI), Naphthalene Diimide (NDI) Thiazole, selenophene, fused thio For example, fused thiophene, naphthothiadiazole, phenothiazine, quinoxaline, or a combination thereof.

The dispersion solvent may be at least one selected from the group consisting of pyridine, toluene, dimethylsulfoxide (DMSO), isopropyl alcohol (IPA), acetone, ethanol, methanol, Water, or a combination thereof.

An embodiment of the present invention provides a method for producing a defect-free graphene, which can produce graphene of a zero defect point at a high yield.

Another embodiment of the present invention provides a dispersion composition of non-defective graphene, in which non-defective graphene is dispersed stably and uniformly in various solvents, and a method of producing the same.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exemplary process schematic diagram of a method of making defect-free graphene according to one embodiment of the present invention.
FIG. 2 is a digital camera photograph and physical property measurement data which can confirm the dispersion state of graphene prepared in Example 1 of the present invention in various solvents. FIG.
Fig. 3 is a photograph (a) of a digital camera of the graphite interlayer compound prepared in Example 1 of the present invention, a photograph (c) of a digital camera of a mixed solution after ultrasonic treatment and a photograph (b) of a digital camera of dried defect- (D, e) and pristine graphite, a KC8 interlayer compound, a Graphene Nanosheet (GNS), and a non-defective graphene prepared in Example 1 X-ray diffraction analysis data (f) for graphene and Raman spectroscopic measurement data (g).
Figure 4 shows the optical microscope photographs and AFM phase (a), Raman spectroscopic measurement data (b) and known micrographs of graphene oxide, reduced graphene oxide, and defect-free graphene prepared in Example 1 of the present invention, (C) is a comparative example data of pin physical property related results.
5 is an X-ray photoelectron spectroscopy (XPS) surface analysis result of defect-free graphene prepared in Example 1 of the present invention.
6 is a photograph of a digital camera obtained by confirming the dispersion characteristics of the dispersion composition of defect-free graphene prepared in Example 2 of the present invention.
7 is a photograph of a digital camera which confirms the dispersion characteristics of the dispersion-free graphene dispersion prepared in Example 3 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

One embodiment of the present invention relates to a method of producing a non-defective graphene having pure graphene-like physical properties and a dispersion method of a defect-free graphene having dispersibility in various solvents through surface modification of the non- And a manufacturing method thereof.

Through this, it is possible to produce graphene having stable dispersion characteristics in various polar / non-polar dispersing solvents by using various surface modifiers without deteriorating physical properties of graphene.

Accordingly, such non-defective graphene can be dispersed in various solvents while maintaining the inherent physical properties of graphene. Therefore, electrode materials such as lightweight / high strength composite materials, heat dissipation materials, materials for nano ink, secondary batteries, fuel cells, And / or coating materials.

Specifically, one embodiment of the present invention comprises the steps of: heat treating a mixture of natural graphite and an alkali metal to produce a graphite intercalation compound; Mixing the graphite intercalation compound with a pyridine-based solvent; And ultrasonically treating the mixed graphite intercalation compound and the pyridine-based solvent. The present invention also provides a method for producing a defect-free graphene. Fig. 1 is a schematic view showing a manufacturing process of such a defect-free graphene fabrication method. However, the present invention is not limited thereto.

By using a pyridine-based solvent as a peeling solvent, it is possible to produce a graphite intercalation compound at a low temperature and a low vacuum condition as compared with the conventional peeling temperature in the production of an alkali metal intercalated graphite intercalation compound, thereby remarkably reducing the process cost .

In addition, peeling using pyridine has a property of stably dissolving electrons transferred to graphite in a pyridine solvent without causing a chemical reaction with graphite when the alkali metal intercalated in the interlayer compound is dissolved in the pyridine solution in an ionic state, And has excellent properties that can maintain the physical properties of graphene as compared with other dispersion solvents.

Further, by carrying out the exfoliation in a pyridine-based exfoliating solvent, it is possible to manufacture a non-defective graphene which retains the inherent physical properties of the graphene without having to undergo oxidation / reduction processes.

More specifically, the pyridine-based exfoliating solvent may include pyridine, a pyridinium compound, or a combination thereof.

The conditions for carrying out the step of producing the graphite intercalation compound are a temperature of not more than 200 DEG C (specifically, not less than 70 DEG C and not more than 200 DEG C), and a vacuum condition of not less than 10 ^-5 Torr and not more than 10 ^-2 Torr . About 300 to 400 ℃ temperature and about ^10-7 To 10 < ^-5 > Torr, the process cost can be drastically reduced by producing the graphite interlayer compound under the low temperature and low vacuum conditions.

The method of manufacturing the defect-free graphene comprises: mixing the graphite intercalation compound with a pyridine-based solvent; And then allowing the mixed graphite intercalation compound and the pyridine-based solvent to be left to expand the graphite interlayer distance of the graphite intercalation compound. By expanding the graphite interlayer distance of the graphite intercalation compound, the peeling efficiency can be improved. The expansion of the interlayer distance may be made by allowing the mixed graphite intercalation compound and the pyridine-based solvent to stand at a temperature not lower than the melting point of the solvent and at a temperature of 0 ° C or lower for 3 hours or more and 48 hours or less. Illustratively, in the case of a pyridine solvent, it can be carried out at a temperature of -41.6 ° C or higher and 0 ° C or lower. The reason for the temperature limitation in the above range for the interlayer expansion is to reduce the rate at which the alkali metal present in the interlayer compound is ionized into the alkali metal ion to the pyridine solvent and the settling time can be flexibly adjusted according to the temperature and the interlayer expansion degree have.

The ultrasonic treatment of the mixed graphite intercalation compound and the pyridine-based solvent may be performed at a temperature of 0 ° C or higher, and 10 ° C or lower, for 10 minutes or longer, and for 24 hours or shorter. Through such ultrasonic treatment, graphene peeling can be performed without generating defects from graphite intercalation compounds in a pyridine-based solvent.

Further, in the step of preparing graphite intercalation compound by heat-treating a mixture of natural graphite and alkali metal, the molar ratio of natural graphite and alkali metal (natural graphite: alkali metal) in the mixture is 1: 0.1 or more, And 1: 0.2 or less. When the amount of the alkali metal is too small in the preparation of the graphite intercalation compound, a problem may arise in formation of a uniform intercalation compound. On the other hand, when the mixing amount of the alkali metal is too large, physical properties may be deteriorated on the surface of the graphene when peeling off the graphene.

The method of manufacturing the defect-free graphene comprises: ultrasonifying the mixed graphite intercalation compound and the pyridine-based solvent; Thereafter, the ultrasonic treated graphite intercalation compound and the pyridine-based solvent mixture may be dried to obtain a defect-free graphene. This is a step of removing the solvent after graphen peeling and obtaining a defect-free graphene.

Another embodiment of the present invention includes the steps of mixing a defect-free graphene, a defect-free graphene surface modifier, and a dispersion solvent prepared according to the manufacturing method of one embodiment of the present invention described above; And applying a physical force to the mixed mixture. ≪ IMAGE >

Since the surface modification of the produced defect-free graphene improves the dispersibility in various dispersion solvents, it can be used in various solvents while maintaining the inherent physical properties. Therefore, it is possible to use lightweight / high strength composite material, heat- Electrode materials for secondary batteries, fuel cells, and barrier / coating materials.

More specifically, the surface can be modified by non-covalent functionalization of the defect-free graphene through the surface modifier, physical attachment, or covalent functionalization, and the dispersibility in various hydrophilic / hydrophobic dispersion solvents can be improved depending on the modifier have. In one embodiment of the present invention, as shown in the following examples, the solvent is selected from the group consisting of pyridine, toluene, dimethylsulfoxide (DMSO), isopropyl alcohol (IPA), acetone ), Ethanol (ethanol), methanol (methanol), water, or a combination thereof, and various solvents having similar physical properties.

The surface modifier may be 3,4,9,10-perylentetracarbonsauredianhydride (PTCDA), thiophene-diketopyrrolopyrrole (TDPP) , Poly (9,9-di- (N, N-dimethylaminopropylfluorenyl-2,7-diyl), PFDMA) , Poly (p-phenylenevinylene), poly (3-hexyl-thiophene), poly [2,6- (4,4- Cyclopenta [2,1-b: 3,4-b '] dithiophene) alt-4,7 (2,1,3-benzothiadiazol)] (2,1-b, 3,4-b '] dithiophene) -but-4,7 (2,1- 3-benzothiadiazole)], PCPDTBT), poly [N-9'-heptadecanyl] -2,7-carbazole-alt-5,5- (4 ', 7'- ', 1', 3'-benzothiadiazole) (Poly [N-9'-heptadecanyl-2,7-carbazole-alt-5,5- (4 ', 7'-di- ', 1', 3'-benzothiadiazole)], PCDTBT), poly [9- (1-octylnonyl) -9H- -2,7-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophendiyl] (Poly [[9- 2,7-diyl-2,5-thiophenediyl-4,7-diyl-2,5-thiophenediyl], PCDTBT), poly (4, (3,2-b: 2'3'-d) silole) -2,6-diyl-alt- (2,1,3-benzothiadiazol- (Poly (4,4-dioctyldithieno (3,2-b: 2 ', 3'-d) silole) -2,6-diyl-6- (2,1,3-benzothiadiazole) , PSBTBT), poly [1- (6- {4,8-bis [(2-ethylhexyl) oxy] -6-methylbenzo [ Yl} -3-fluoro-4-methylthieno [3,4-b] thiophen- (2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4,5- b '] dithiophen-2-yl} -3-fluoro-4- methylthieno [3,4- b] thiophen- (PDI), Nafion (R), Carbazole, Thiazole (PDI), Naphthalene Diimide (NDI) Thiazole, selenophene, fused thio (Fused thiophene), may be saw-naphthoquinone thiadiazole (Naphthothiadiazole), phenothiazine Im-triazine (Phenothiazine), quinoxaline (Quinoxaline), or a combination thereof. More specifically, 3,4,9,10-perylentetracarbonsauredianhydride (PTCDA), thiophene-diketopyrrolopyrrole (TDPP) , Poly (9,9-di- (N, N-dimethylaminopropylfluorenyl-2,7-diyl), PFDMA) Nafion.RTM .. The surface of the defect-free graphene can be modified by non-covalent functionalization or the like through such an organic molecule or a conductive polymer surface modifier, and the dispersibility in the above-mentioned solvent can be improved .

In the above production method, by applying a physical force to the mixed mixture, the surface modifier may be physically or chemically attached to the surface of the defect-free graphene. Specifically, the physical force may be applied through stirring, ultrasonic treatment, or a combination thereof. Through these steps, a dispersion composition in which the surface modifier is physically bonded to the surface of the defect-free graphene in the composition, or non-covalent functionalization or covalent functionalization improves the dispersibility in the solvent can be produced.

Another embodiment of the present invention is a defect-free graphene produced according to the manufacturing method of one embodiment of the present invention; And a surface modifier that is physically or chemically attached to the defect-free graphene; And a dispersion solvent.

This is a defect-free graphene dispersion composition prepared according to another embodiment of the present invention. As shown in the following examples, the surface modification of the produced defect-free graphene enables the dispersion of fine grains in various dispersion solvents Various applications such as lightweight / high strength composite materials, heat dissipation materials, nano ink materials, electrode materials such as secondary batteries and fuel cells, and barrier / coating materials can be used by dispersing them in various solvents while maintaining their inherent physical properties by improving acidity It may be possible to expand into the field.

The above description of the surface modifier and the solvent is the same as described above, and thus will not be described.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following examples are only a preferred embodiment of the present invention, and the present invention is not limited to the following examples.

Example

Example 1: Preparation of defect-free graphene

1 g of pristine graphite and 0.407 g of potassium metal (molar ratio of graphite to potassium = 8: 1) were charged into a Pyrex tube, vacuum-poured for 30 minutes, vacuumed at 10 ^-2 Torr, And then the graphite intercalation compound was synthesized. The prepared graphite intercalation compound had a bright gold color.

Thereafter, 100 mg of the graphite intercalation compound was mixed with 100 mL of pyridine (Pyridine (purchased from Sigma Aldrich) as a peeling solvent, and the mixture was stored at a melting point of -41.6 ° C or higher and a temperature of 0 ° C or lower for 24 hours, The interlayer distance was extended.

Then, graphene nanosheets with interlayer interlayer extended graphite intercalation compounds were ultrasonicated in a water bath at 5 ℃ for 1 hour to prepare defect free graphene.

Ultrasonic treatment in Example 1 and filtration followed by drying in an oven (60 to 80 ° C) yielded a non-defective graphene powder.

Example 2: Preparation of dispersion composition of defect-free graphene

After Example 1, 10 mg of non-defective graphene and 1 mg of surface modifier (PTCDA, PDPP, PFDMA) were dispersed in 10 mL of pyridine solvent and stirred at 60 ° C for 24 hours to perform non-covalent functionalization in non-cured graphene.

Example 3: Preparation of dispersion composition of defect-free graphene

After Example 1, 4 mL of graphene and Nafion (D-521 dispersion, 5% w / w in water and 1-propanol) dispersed in a pyridine dispersion solvent at a dispersion concentration of 1 mg / Was dispersed in 12 mL of various dispersing solvents (Toluene, DMSO, IPA, Acetone, Ethanol, Methanol, DI) and noncovalent functionalization of non-cured graphene was performed using water bath ultrasonic for 90 minutes.

Experimental Example

Experimental Example 1

FIG. 2 is a graph showing the results obtained by mixing 10 mg of the single / multi-layer graphene prepared in Example 1 in a solvent of 10 mL of hexane, toluene, THF, EtOH, pyridine, DMF, DMSO and DI, Photographs before and after the ultrasonic treatment for 1 hour, and physical property measurement data.

After completion of the reaction, each graphene was measured for physical properties of graphene using Raman spectroscopy. The most prominent in the Raphan spectroscope of graphene is the G peak near 1580 cm ^-1 and the 2D peak near 2700 cm ^-1 . Both peaks are found at similar positions in the case of graphite. In addition to these two peaks, a D peak is found near 1350 cm ^-1 depending on the physical properties of graphene. This is due to the defect due to crystal defects in grains. In the case of graphene, observation is only possible in the vicinity of the edge of the specimen, do. From this data, the ratio of the intensity of D Peak to G peak, which indicates the crystallinity of the graphene structure, was calculated and the change of physical properties was confirmed.

As can be seen from FIG. 2, it was confirmed that the pyridine solvent completely retained its inherent physical properties.

Experimental Example 2

3 is a photograph (a) of a digital camera of the graphite interlayer compound prepared in Example 1, a photograph (c) of a digital camera of a mixed solution after ultrasonic treatment and a photograph (b) of a digital camera of dried defect- (D, e), pristine graphite, KC8 intercalation compound, Graphene Nanosheet (GNS), and graphene nanosheet (GNS) prepared in Example 1, Ray diffraction analysis data (f) and Raman spectroscopic measurement data (g).

Three characteristic peaks (1350 cm ^-1 : D, 1580 cm ^-1 : G, 2700 cm ^{- 1} : 2D) were observed in the prepared graphene through Raman spectroscopy. The D peak observed at 1350 cm ^-1 is known to be a peak induced by a defect in the structure of graphene, and the graphene produced in this embodiment has a very low structural defect. These results confirm that the graphene produced successfully without structural defects.

Furthermore, it was confirmed that K metal was formed as an intercalant of intercalation compound through XRD. As the manufacturing process temperature increased, the intensity of 26.4 ° appeared from the distance between graphite layers (d002: 3.34 Å) decreased and insertion of alkali metal ion (D002: 5.71 Å), which is indicated by the intensity of the incident light, increases. Through the control of the above-mentioned process temperature and pressure, it is possible to further expand the space between the graphite layers, and it can be confirmed that a more positive effect can be expected in the production of graphene.

Experimental Example 3

FIG. 4 shows optical microscope photographs of defect-free graphene, graphene oxide, and reduced graphene oxide prepared in Example 1, AFM phase (a), Raman spectroscopic measurement data (b) This is the data for comparison of pin physical property related results.

Raman spectroscopy can confirm that the prepared defect-free graphene retains its physical properties remarkably in comparison with graphene oxide and reduced graphene oxide. The physical properties of the defect-free graphenes prepared in this example are as follows: It can be confirmed that it has almost the same physical properties as a good mechanical peeled graphene.

Experimental Example 4

5 is an X-ray photoelectron spectroscopy (XPS) surface analysis result of the defect-free graphene prepared in Example 1. FIG.

It can be confirmed that the C-C bonding energy value of 284.5 eV is almost unchanged even after peeling of the multi / multi-layer graphene, and that the content of oxygen atoms contained in the initial graphite hardly increases to less than 2%.

Experimental Example 5

6 is a photograph of a digital camera obtained by confirming the dispersion characteristics of the dispersion composition of defect-free graphene prepared in Example 2 above. Photoluminacne (PL) quenching (non-covalent functionalization) of non-covalent functional grafts using TDPP confirms the formation of non-covalent functionalization.

Experimental Example 6

7 is a photograph of a digital camera obtained by confirming the dispersion characteristics of the dispersion composition of defect-free graphene prepared in Example 3 above. The variation of the dispersion characteristics of the non-defective graphene according to the change of the dispersion solvent can be confirmed. Specifically, it can be confirmed that the dispersibility is very excellent in various dispersing solvents of polarity / non-polarity.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (19)

Preparing graphite intercalation compounds by heat treating a mixture of natural graphite and alkali metal under vacuum conditions of greater than 10 ^-5 Torr and less than 10 ^-2 Torr;
Mixing the graphite intercalation compound with pyridine;
Exposing the mixed graphite intercalation compound and pyridine to expand the graphite interlayer distance of the graphite interlayer compound; And
Ultrasonically treating the mixed graphite intercalation compounds and pyridine,
Exposing the mixed graphite intercalation compound and pyridine to expand the graphite interlayer distance of the graphite intercalation compound,
-41.6 DEG C or more, and 0 DEG C or less, 3 hours or more, and 48 hours or less,
Graphene. The method of claim 1,
Wherein the heat treatment temperature of the step of preparing graphite intercalation compound by heat-treating the natural graphite and the mixture of alkali metals,
70 < 0 > C, and 200 < 0 &
Graphene. The method of claim 1,
The heat treatment time of the step of preparing the graphite intercalation compound by heat-treating the natural graphite and the alkali metal mixture,
30 minutes, and 90 minutes or less,
Graphene. delete delete delete delete The method of claim 1,
Ultrasonically treating the mixed graphite intercalation compounds and pyridine,
At a temperature of 0 ° C or more, and 10 ° C or less, for 10 minutes or more, and for a time of 24 hours or less.
Graphene. The method of claim 1,
Heat-treating the natural graphite and the mixture of alkali metals to prepare graphite intercalation compounds,
The molar ratio of natural graphite and alkali metal in the mixture (natural graphite: alkali metal)
1: 0.1 or more, and 1: 0.2 or less.
Graphene. The method of claim 1,
Ultrasonicing the mixed graphite intercalation compound and pyridine; Since the,
Drying the ultrasonic treated graphite intercalation compound and the pyridine mixture to obtain defect-free graphene;
Graphene. Mixing the graphene, the graphene surface modifier, and the dispersion solvent prepared in claim 1;
Applying a physical force to the mixed mixture
Graphene dispersion composition. 12. The method of claim 11,
Applying a physical force to the mixed mixture,
Wherein the surface modifier is physically or chemically attached to the graphene surface.
Graphene dispersion composition. The method of claim 12,
Applying a physical force to the mixed mixture,
Wherein the surface modifier is attached to the graphene surface via non-covalent interaction.
Graphene dispersion composition. 12. The method of claim 11,
Applying a physical force to the mixed mixture,
Wherein the treatment is carried out through agitation, stirring, ultrasonic treatment, or a combination thereof.
Graphene dispersion composition. 12. The method of claim 11,
The surface-
3,4,9,10-Perylentetracarbonsauredianhydrid (PTCDA), Thiophene-Diketopyrrolopyrrole (TDPP), Poly (9, N, N-dimethylaminopropylfluorenyl-2,7-diyl, PFDMA), poly (para- Poly (3-hexyl-thiophene), poly [2,6- (4,4-bis- (2- (2,1-b) 3,4-b '] thiophene) -alt-4,7 (2,1,3-benzothiadiazol)] (Poly [ Cyclopenta [2,1-b; 3,4-b '] dithiophene) -tallow-4,7 (2,1,3-benzothiadiazole)] - , PCPDTBT), poly [N-9'-heptadecanyl] -2,7-carbazole-alt-5,5- (4 ', 7'- 3 '-benzothiadiazole)] (Poly [N-9'-heptadecanyl-2,7-carbazole-alt-5,5- (4', 7'-di- 3'-benzothiadiazole)], PCDTBT), poly [9- (1-octylnonyl) -9H-carbazole-2,7-diyl] 2,6-dihydro-5H-pyrazol-3-yl) -phenyl] -2,3-benzothiadiazol-4,7-diyl-2,5-thiophendiyl] (Poly [[9- (1-octylnonyl) 2,5-thiophenediyl-2,7-diyl-2,5-thiophenediyl], PCDTBT), poly 2'3'-d) silole) -2,6-diyl-alt- (2,1,3-benzothiadiazol-4,7- b: 2 ', 3'-d) silole) -2,6-diyl-alt- (2,1,3-benzothiadiazole) -4,7-diyl, PSBTBT) Methyl-benzo [1,2-b: 4,5-b '] thiophen-2-yl} -3-fluoro- (2-ethylhexyl) oxy] -6-methylbenzo [1, < / RTI & 2-b: 4,5-b '] dithiophen-2-yl} -3-fluoro-4-methylthieno [3,4-b] thiophen- (Naphthalene Diimide, NDI), Perylene Diimide (PDI), Nafion (R), Carbazole, Thiazole, Selenophene, Fused thiophene Fused thiophene, I The shoot thiadiazole (Naphthothiadiazole), phenothiazine Im-triazine (Phenothiazine), quinoxaline (Quinoxaline), or to a combination thereof,
Graphene dispersion composition. 12. The method of claim 11,
The above-
The solvent is preferably selected from the group consisting of Pyridine, Toluene, Dimethyl Sulfoxide (DMSO), Isopropyl alcohol (IPA), Acetone, Ethanol, Methanol, The combination,
Graphene dispersion composition. Graphene prepared in claim 1; And
A surface modifier that is physically or chemically attached to the graphene; And
A dispersion solvent;
Graphene dispersion composition. The method of claim 17,
The surface-
3,4,9,10-Perylentetracarbonsauredianhydrid (PTCDA), Thiophene-Diketopyrrolopyrrole (TDPP), Poly (9, N, N-dimethylaminopropylfluorenyl-2,7-diyl, PFDMA), poly (para- Poly (p-phenylenevinylene), poly (3-hexyl-thiophene), poly
Cyclopenta [2,1-b (3,4-b '] dithiophene) -alt-4,7,7 (2-ethylhexyl) , 1,3-benzothiadiazole)] (Poly [2,6- (4,4-bis- (2-ethylhexyl) -4H-cyclopenta [ (4 ', 7', 7 ', 7 ") -7-benzothiadiazole], PCPDTBT), poly [N-9'-heptadecanyl] -2,7- (4'-heptadecanyl-2,7-carbazole-alt-5,5- (4 ', 3'- , 7'-di-2-thienyl-2 ', 1', 3'-benzothiadiazole)], PCDTBT), poly [9- (1-octylnonyl) -9H-carbazole- 2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophendi] (Poly [[9- (1-octylnonyl) -9H-carbazole -2,7-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl], PCDTBT), poly (4,4-dioctyldicyano 3,2-b: 2'3'-d) silole) -2,6-diyl-alt- (2,1,3-benzothiadiazol- 2,6-diyl-alt- (2,1,3-benzothiadiazole) -4,7-diyl, PSBTBT), poly [1- (6- {4,8-bis [(2- 3,4-b] thiophen-2-yl} -3-fluoro-4-methylthieno [3,4- b] Bis [(2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4,5- 2-yl] -3-fluoro-4-methylthieno [3,4-b] thiophen-2-yl) -1-octanone], PBDTTT-CF), naphthalene diimide (NDI) , Perylene Diimide (PDI), Nafion (R), Carbazole, Thiazole, Selenophene, Fused thiophene, Naphthothiadiazole, Phenothiazine, Quinoxaline, or a combination thereof.
Graphene dispersion composition. The method of claim 17,
The above-
The solvent is preferably selected from the group consisting of Pyridine, Toluene, Dimethyl Sulfoxide (DMSO), Isopropyl alcohol (IPA), Acetone, Ethanol, Methanol, The combination,
Graphene dispersion composition.

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