KR20220002127A - Method for purifying carbon nanotubes using ionic liquid - Google Patents

Method for purifying carbon nanotubes using ionic liquid Download PDF

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KR20220002127A
KR20220002127A KR1020210083743A KR20210083743A KR20220002127A KR 20220002127 A KR20220002127 A KR 20220002127A KR 1020210083743 A KR1020210083743 A KR 1020210083743A KR 20210083743 A KR20210083743 A KR 20210083743A KR 20220002127 A KR20220002127 A KR 20220002127A
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carbon nanotubes
methylimidazolium
butyl
ionic liquid
dispersion solution
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KR102542642B1 (en
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김태원
박재철
이전량
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한국생산기술연구원
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    • C01B32/00Carbon; Compounds thereof
    • C01B32/15Nano-sized carbon materials
    • C01B32/158Carbon nanotubes
    • C01B32/168After-treatment
    • C01B32/17Purification
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    • B01J19/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/10Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing sonic or ultrasonic vibrations
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    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00Carbon; Compounds thereof
    • C01B32/15Nano-sized carbon materials
    • C01B32/158Carbon nanotubes
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    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2202/00Structure or properties of carbon nanotubes
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Abstract

The present invention relates to a method for purifying carbon nanotubes which comprises the following steps of: (a) dispersing unpurified carbon nanotubes comprising impurities in an ionic liquid to prepare a dispersion solution; (b) irradiating ultrasonic waves to the dispersion solution; and (c) obtaining a high-purity carbon nanotube in which the impurities are separated from the dispersion solution irradiated with the ultrasonic waves. The method for purifying carbon nanotubes according to the present invention uses the physicochemical properties of an ionic liquid to simply purify the carbon nanotubes with a high capacity and with high purity without impairing the intrinsic properties of the carbon nanotubes.

Description

이온성 액체를 이용한 탄소나노튜브의 정제방법{METHOD FOR PURIFYING CARBON NANOTUBES USING IONIC LIQUID}Purification method of carbon nanotubes using ionic liquids {METHOD FOR PURIFYING CARBON NANOTUBES USING IONIC LIQUID}

본 발명은 탄소나노튜브의 정제방법에 관한 것으로, 더욱 상세하게는 이온성 액체를 이용한 탄소나노튜브의 정제방법에 관한 것이다.The present invention relates to a method for purifying carbon nanotubes, and more particularly, to a method for purifying carbon nanotubes using an ionic liquid.

탄소나노튜브는 전자, 디스플레이, 이차전지 등에 사용되는 핵심소재로 그 응용분야가 매우 다양한 미래소재로서, 우수한 전기/전자적인 특성, 낮은 열팽창성, 높은 열전도성, 매우 높은 기계적 강도 등을 가지고 있어 터치스크린용 전극소재분야, 수퍼캐퍼시터용 전극소재분야, 이차전지용 양극도전소재분야, 수소저장소재분야, 나노전자소자분야, 센서소재분야 등 다양한 전기전자용 소재분야에 적용될 수 있다.Carbon nanotubes are a core material used in electronics, displays, and secondary batteries. As a future material with a wide range of applications, it has excellent electrical/electronic properties, low thermal expansion, high thermal conductivity, and very high mechanical strength. It can be applied to various electrical and electronic material fields such as screen electrode material field, super capacitor electrode material field, anode conductive material field for secondary battery, hydrogen storage material field, nano electronic device field, sensor material field, etc.

탄소나노튜브는 금속 나노촉매를 이용하여 합성되는데, 탄소나노튜브를 전자소자, 전지 등에 응용하기 위해서는 금속 나노촉매를 최종적으로 제거해야 한다. 상기 금속 나노촉매를 제거하기 위한 방법으로 물리적 분리방법, 기상산화법, 액상산화법이 있다. 물리적 분리방법은 탄소나노튜브를 계면활성제에 분산시킨 후 크로마토그래피 필터링과 원심분리 공정을 통해 물리적으로 잔류 금속 나노촉매를 분리정제하는 방법이나, 이 방법으로 정제할 수 있는 탄소나노튜브의 처리 용량이 매우 제한적으로 생산성이 매우 낮은 문제가 있다. 또한 기상산화법은 공기, 산소, 오존, H2S 등의 고온 분위기에서 일차적으로 금속 나노촉매를 감싸고 있는 비정질 탄소상을 제거한 후, 산용액에서 금속 나노촉매를 제거하는 방법이다. 그러나 탄소나노튜브의 원래 가지고 있는 우수한 물리화학적 특성이 열화되는 문제가 있다. 또한 액상산화법은 HNO3, HClO4, KMnO4, H2SO4 등의 강산성 용액을 이용하여 금속 나노촉매를 제거하는 방법으로, 공정 중 사용되는 강산성 용액에 의해 탄소나노튜브의 구조가 파괴되어 물성을 변형시킬 뿐만 아니라, 탄소나노튜브 표면에 공정 잔해물이 부착되어 재오염 문제를 야기할 수 있다.Carbon nanotubes are synthesized using a metal nanocatalyst. In order to apply the carbon nanotubes to electronic devices and batteries, the metal nanocatalyst must be finally removed. As a method for removing the metal nanocatalyst, there are a physical separation method, a gas phase oxidation method, and a liquid phase oxidation method. The physical separation method is a method of physically separating and purifying residual metal nanocatalysts through chromatographic filtering and centrifugation after dispersing carbon nanotubes in a surfactant, but the processing capacity of carbon nanotubes that can be purified by this method is There is a problem with very limited productivity and very low productivity. In addition, the vapor phase oxidation method is a method of removing the metal nanocatalyst from an acid solution after first removing the amorphous carbon phase surrounding the metal nanocatalyst in a high temperature atmosphere such as air, oxygen, ozone, and H 2 S. However, there is a problem in that the excellent physical and chemical properties of carbon nanotubes are deteriorated. In addition, the liquid phase oxidation method is a method of removing a metal nanocatalyst using a strong acid solution such as HNO 3 , HClO 4 , KMnO 4 , H 2 SO 4 . In addition to deforming the carbon nanotubes, process debris may adhere to the surface of the carbon nanotubes, causing recontamination problems.

따라서 종래의 탄소나노튜브의 정제방법은 정제수율, 비용, 탄소나노튜브의 물성 변화 등 다양한 문제점을 내포하고 있어, 새로운 정제방법의 개발이 필요하다.Therefore, the conventional purification method for carbon nanotubes contains various problems such as purification yield, cost, and changes in physical properties of carbon nanotubes, and thus, it is necessary to develop a new purification method.

본 발명의 목적은 상기 문제점을 해결하기 위한 것으로, 이온성 액체의 물리화학적 특성을 이용함으로써, 탄소나노튜브의 고유 물성을 해치지 않으면서, 대용량으로, 간단하게 고순도로 정제할 수 있는 탄소나노튜브의 정제방법을 제공하는데 있다. An object of the present invention is to solve the above problems, and by using the physicochemical properties of an ionic liquid, carbon nanotubes that can be easily purified in a large capacity and high purity without harming the intrinsic properties of the carbon nanotubes. To provide a purification method.

또한, 고온공정 및 강산성 용액 또는 가스 등을 이용하지 않아 친환경적이며, 고가의 공정장비를 이용하지 않아 정제공정 비용을 절감할 수 있는 탄소나노튜브의 정제방법을 제공하는데 있다.In addition, there is provided a method for purifying carbon nanotubes that is environmentally friendly because it does not use a high-temperature process and a strong acid solution or gas, and can reduce the cost of the purification process by not using expensive process equipment.

본 발명의 일 측면에 따르면, (a) 불순물을 포함하는 미정제 탄소나노튜브를 이온성 액체에 분산시켜 분산용액을 제조하는 단계; (b) 상기 분산용액에 초음파를 조사하는 단계; 및 (c) 상기 초음파가 조사된 분산용액으로부터 고순도 탄소나노튜브를 수득하는 단계;를 포함하는 탄소나노튜브의 정제방법이 제공된다.According to one aspect of the present invention, (a) preparing a dispersion solution by dispersing the crude carbon nanotubes containing impurities in an ionic liquid; (b) irradiating ultrasonic waves to the dispersion solution; and (c) obtaining high-purity carbon nanotubes from the dispersion solution irradiated with ultrasonic waves.

상기 이온성 액체가 지방족계 이온성 액체, 이미다졸륨계 이온성 액체 및 피리디늄계 이온성 액체로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The ionic liquid may include at least one selected from the group consisting of an aliphatic ionic liquid, an imidazolium-based ionic liquid, and a pyridinium-based ionic liquid.

상기 이온성 액체가 이미다졸륨계 이온성 액체를 포함할 수 있다.The ionic liquid may include an imidazolium-based ionic liquid.

상기 이미다졸륨계 이온성 액체가 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4), 1-부틸-3-메틸이미다졸리움 헥사플루오로포스페이트(1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF6), 1-부틸-3-메틸이미다졸륨 비스(트리플루오로메틸설포닐) 이미드(1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide: BMIM-TFSI), 1-에틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-ethyl-3-methylimidazolium tetrafluoroborate: EMIM-BF4), 1-에틸-3-메틸이미다졸륨비스(트리플루오로메틸설포닐) 이미드(1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: EMIM-TFSI), 1-에틸-3-메틸이미다졸륨 트리시아노메타나이드(1-Ethyl-3-methylimidazolium Tricyanomethanide: EMIM-TCM), 1-에틸-3-메틸이미다졸륨 테트라시아노보레이트(1-ethyl-3-methylimidazolium tetracyanoborate: EMIM-TCB), 1-에틸-3-메틸이미다졸륨 메틸 설페이트(1-ethyl-3-methylimidazolium methyl sulfate: EMIM-SO4), 디에틸메틸(2-메톡시에틸)암모늄 테트라프루오로보레이트(diethylmethyl(2-methoxyethyl)ammonium tetrafluoroborate: DMIM-BF4), 디에틸메틸(2-메톡시에틸)암모늄 비스(트리플루오로메틸설포닐) 이미드)(diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide): DMIM-TFSI), 1-옥틸-3-메틸이미다졸륨 비스(트리플루오르메틸 술포닐)이미드(1-Octyl-3-methylimidazorium bis(trifluoromethyl sulfonyl)imide: OMIM-TFSI)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The imidazolium-based ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate (1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF 4 ), 1-butyl-3-methylimidazolium hexafluoro Rophosphate (1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF 6 ), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) ) imide: BMIM-TFSI), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF 4 ), 1-ethyl-3-methylimidazolium bis ( Trifluoromethylsulfonyl) imide (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: EMIM-TFSI), 1-ethyl-3-methylimidazolium tricyanomethanide (1-Ethyl-3-methylimidazolium) Tricyanomethanide: EMIM-TCM), 1-ethyl-3-methylimidazolium tetracyanoborate (1-ethyl-3-methylimidazolium tetracyanoborate: EMIM-TCB), 1-ethyl-3-methylimidazolium methyl sulfate (1 -ethyl-3-methylimidazolium methyl sulfate: EMIM-SO 4 ), diethylmethyl(2-methoxyethyl)ammonium tetrafluoroborate: DMIM-BF 4 ), diethylmethyl (2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide) (diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide): DMIM-TFSI), 1-octyl-3-methylimidazolium bis(trifluorime It may include at least one selected from the group consisting of tyl sulfonyl) imide (1-Octyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide: OMIM-TFSI).

상기 이미다졸륨계 이온성 액체가 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4), 1-부틸-3-메틸이미다졸리움 헥사플루오로포스페이트(1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF6), 1-부틸-3-메틸이미다졸륨 비스(트리플루오로메틸설포닐) 이미드(1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide: BMIM-TFSI)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The imidazolium-based ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate (1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF 4 ), 1-butyl-3-methylimidazolium hexafluoro Rophosphate (1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF 6 ), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) ) imide: BMIM-TFSI) may include one or more selected from the group consisting of.

상기 미정제 탄소나노튜브는 단일벽 탄소나노튜브, 또는 다중벽 탄소나노튜브로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The crude carbon nanotubes may include at least one selected from the group consisting of single-walled carbon nanotubes or multi-walled carbon nanotubes.

상기 불순물이 금속, 비정질 탄소, 흑연, 탄소 나노입자 및 할로겐 원소로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The impurities may include at least one selected from the group consisting of metal, amorphous carbon, graphite, carbon nanoparticles, and a halogen element.

상기 금속이 Ni, Co, Cu, Fe, Mg, Pd, Al, Si, 이들의 혼합물 및 이들의 산화물로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The metal may include at least one selected from the group consisting of Ni, Co, Cu, Fe, Mg, Pd, Al, Si, mixtures thereof, and oxides thereof.

단계 (b)가 상기 분산용액에 초음파를 조사하여 상기 미정제 탄소나노튜브에 포함된 상기 불순물을 분리시키는 단계;일 수 있다.Step (b) may be a step of separating the impurities contained in the crude carbon nanotubes by irradiating the dispersion solution with ultrasonic waves.

단계 (b)에서 상기 초음파를 0.5 내지 5시간 동안 조사할 수 있다.In step (b), the ultrasonic wave may be irradiated for 0.5 to 5 hours.

단계 (b)에서 상기 초음파를 10 내지 150 kHz의 주파수에서 조사할 수 있다.In step (b), the ultrasonic wave may be irradiated at a frequency of 10 to 150 kHz.

단계 (b)에서 상기 초음파를 10 내지 300 W의 세기로 조사할 수 있다.In step (b), the ultrasonic wave may be irradiated with an intensity of 10 to 300 W.

단계 (c)가 상기 초음파가 조사된 분산용액을 원심분리 또는 필터링하여 상기 초음파가 조사된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;일 수 있다.Step (c) may be a step of centrifuging or filtering the dispersion solution irradiated with ultrasonic waves to obtain high-purity carbon nanotubes in which the impurities are separated from the dispersion solution irradiated with ultrasonic waves;

단계 (c)가 (c-1) 상기 초음파가 조사된 분산용액에 세정용매를 혼합하여 세정된 분산용액을 제조하는 단계; (c-2) 상기 세정된 분산용액을 필터링하여 상기 세정된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;를 포함할 수 있다.Step (c) is (c-1) preparing a washed dispersion solution by mixing a cleaning solvent with the dispersion solution irradiated with ultrasonic waves; (c-2) filtering the washed dispersion solution to obtain high-purity carbon nanotubes from which the impurities are separated from the washed dispersion solution;

단계 (c-2)에서 상기 필터링이 진공상태에서 수행될 수 있다.In step (c-2), the filtering may be performed in a vacuum state.

상기 세정용매가 아세톤, 알코올, 에탄올, 이소프로필알코올(IPA) 및 증류수로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The cleaning solvent may include at least one selected from the group consisting of acetone, alcohol, ethanol, isopropyl alcohol (IPA) and distilled water.

단계 (c) 이후에, 상기 고순도 탄소나노튜브를 건조하는 단계 (d);를 추가로 포함할 수 있다.After step (c), drying the high-purity carbon nanotubes (d); may further include.

단계 (d)에서 상기 건조가 50 내지 300℃의 온도에서 수행될 수 있다.The drying in step (d) may be performed at a temperature of 50 to 300 ℃.

본 발명의 다른 일 측면에 따르면, 상기 탄소나노튜브의 정제방법에 따라 제조된 고순도 탄소나노튜브가 제공된다.According to another aspect of the present invention, there is provided a high-purity carbon nanotube manufactured according to the method for purifying the carbon nanotube.

본 발명의 또 다른 일 측면에 따르면, 상기 고순도 탄소나노튜브를 포함하고, 터치스크린용 전극, 수퍼캐퍼시터용 전극, 이차전지용 양극, 수소저장소자, 및 센서로 이루어진 군으로부터 선택된 어느 하나를 포함하는 전자소자가 제공된다.According to another aspect of the present invention, an electron comprising the high-purity carbon nanotube and any one selected from the group consisting of an electrode for a touch screen, an electrode for a supercapacitor, a positive electrode for a secondary battery, a hydrogen storage device, and a sensor A device is provided.

본 발명에 따른 탄소나노튜브의 정제방법은 이온성 액체의 물리화학적 특성을 이용함으로써, 탄소나노튜브의 고유 물성을 해치지 않으면서, 대용량으로, 간단하게 고순도로 정제할 수 있는 효과가 있다.The carbon nanotube purification method according to the present invention has the effect of purifying the carbon nanotubes in a large capacity and with high purity simply by using the physicochemical properties of the ionic liquid, without impairing the intrinsic properties of the carbon nanotubes.

또한, 고온공정 및 강산성 용액 또는 가스 등을 이용하지 않아 친환경적이며, 고가의 공정장비를 이용하지 않아 정제공정 비용을 절감할 수 있는 효과가 있다.In addition, it is environmentally friendly because it does not use a high-temperature process and a strong acid solution or gas, and there is an effect that can reduce the cost of the purification process because expensive process equipment is not used.

도 1은 본 발명에 따른 탄소나노튜브의 정제방법의 순서도이다.
도 2a 및 2b는 본 발명에 따른 비교예 1 및 실시예 1의 SEM 이미지이다.
도 3은 본 발명에 따른 비교예 1 및 실시예 1의 라만 스펙트라 분석 그래프이다.
1 is a flowchart of a method for purifying carbon nanotubes according to the present invention.
2A and 2B are SEM images of Comparative Examples 1 and 1 according to the present invention.
3 is a Raman spectra analysis graph of Comparative Example 1 and Example 1 according to the present invention.

이하, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자가 용이하게 실시할 수 있도록 첨부된 도면을 참조하여 본 발명의 실시예를 상세히 설명하도록 한다. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention.

그러나, 이하의 설명은 본 발명을 특정한 실시 형태에 대해 한정하려는 것이 아니며, 본 발명을 설명함에 있어서 관련된 공지 기술에 대한 구체적인 설명이 본 발명의 요지를 흐릴 수 있다고 판단되는 경우 그 상세한 설명을 생략한다.However, the following description is not intended to limit the present invention to specific embodiments, and when it is determined that detailed descriptions of related known technologies may obscure the gist of the present invention in describing the present invention, the detailed description thereof will be omitted. .

본원에서 사용한 용어는 단지 특정한 실시예를 설명하기 위해 사용된 것으로, 본 발명을 한정하려는 의도가 아니다. 단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함한다. 본 출원에서, "포함하다" 또는 "가지다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, element, or combination thereof described in the specification exists, and includes one or more other features or It should be understood that the possibility of the presence or addition of numbers, steps, acts, elements, or combinations thereof is not precluded in advance.

또한, 이하에서 사용될 제1, 제2 등과 같이 서수를 포함하는 용어는 다양한 구성요소들을 설명하는데 사용될 수 있지만, 상기 구성요소들은 상기 용어들에 의해 한정되지는 않는다. 상기 용어들은 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 사용된다. 예를 들어, 본 발명의 권리 범위를 벗어나지 않으면서 제1 구성요소는 제2 구성요소로 명명될 수 있고, 유사하게 제2 구성요소도 제1 구성요소로 명명될 수 있다In addition, terms including ordinal numbers such as first, second, etc. to be used below may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

또한, 어떤 구성요소가 다른 구성요소 상에 "형성되어" 있다거나 "적층되어" 있다고 언급된 때에는, 그 다른 구성요소의 표면 상의 전면 또는 일면에 직접 부착되어 형성되어 있거나 적층되어 있을 수도 있지만, 중간에 다른 구성요소가 더 존재할 수도 있다고 이해되어야 할 것이다.In addition, when it is said that a certain component is "formed" or "stacked" on another component, it may be formed or laminated by being directly attached to the front surface or one surface on the surface of the other component, but in the middle It should be understood that there may be other components in the .

도 1은 본 발명에 따른 탄소나노튜브의 정제방법의 순서도이다.1 is a flowchart of a method for purifying carbon nanotubes according to the present invention.

이하, 도 1을 참고하여, 본 발명의 탄소나노튜브의 정제방법에 대하여 설명하도록 한다.Hereinafter, a method for purifying carbon nanotubes of the present invention will be described with reference to FIG. 1 .

먼저, 불순물을 포함하는 미정제 탄소나노튜브를 이온성 액체에 분산시켜 분산용액을 제조한다(단계 a).First, a dispersion solution is prepared by dispersing crude carbon nanotubes containing impurities in an ionic liquid (step a).

이온성 액체란, 유기양이온과 무기음이온으로 구성되어 있어 있으며, 실온~400℃ 온도 범위에서 액체상을 유지하는 화합물을 말한다. 이온성 액체는 고온 안정성이며 액체 온도 범위가 넓은, 증기압이 거의 0이고, 이온성이면서 저점성, 높은 산화·환원 내성 및 높은 용해성을 갖는다. 또한 이온성 액체는 친수성이어도 소수성 일 수 있고, 또 그 종류는 특별히 제한되는 것이 아니다.The ionic liquid refers to a compound that is composed of an organic cation and an inorganic anion, and maintains a liquid phase in a temperature range of room temperature to 400°C. The ionic liquid is stable at high temperature, has a wide liquid temperature range, has almost zero vapor pressure, is ionic and has low viscosity, high oxidation/reduction resistance, and high solubility. In addition, the ionic liquid may be hydrophobic even if it is hydrophilic, and the type is not particularly limited.

상기 이온성 액체가 지방족계 이온성 액체, 이미다졸륨계 이온성 액체 및 피리디늄계 이온성 액체로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있고, 바람직하게는 이미다졸륨계 이온성 액체를 포함할 수 있다.The ionic liquid may include at least one selected from the group consisting of an aliphatic ionic liquid, an imidazolium-based ionic liquid, and a pyridinium-based ionic liquid, and preferably include an imidazolium-based ionic liquid. can

상기 지방족계 이온성 액체는 N,N,N-트리메틸-N-프로필암모늄 비스(트리플루오로메탄술포닐) 이미드(TMPA-TFSI), N-메틸-N-프로필 피페리디늄 비스(트리플루오로메탄술포닐) 이미드, N,N-디에틸-N-메틸N-(2-메톡시에틸) 암모늄비스(트리플루오로메탄술포닐) 이미드, N,N-디에틸-N-메틸-N-(2-메톡시에틸) 암모늄 테트라플루오로 붕산염 등으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The aliphatic ionic liquid is N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (TMPA-TFSI), N-methyl-N-propyl piperidinium bis(trifluoro Romethanesulfonyl) imide, N,N-diethyl-N-methylN-(2-methoxyethyl)ammoniumbis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl It may include at least one selected from the group consisting of -N-(2-methoxyethyl)ammonium tetrafluoroborate and the like.

상기 이미다졸륨계 이온성 액체는 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4), 1-부틸-3-메틸이미다졸리움 헥사플루오로포스페이트(1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF6), 1-부틸-3-메틸이미다졸륨 비스(트리플루오로메틸설포닐) 이미드(1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide: BMIM-TFSI), 1-에틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-ethyl-3-methylimidazolium tetrafluoroborate: EMIM-BF4), 1-에틸-3-메틸이미다졸륨비스(트리플루오로메틸설포닐) 이미드(1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: EMIM-TFSI), 1-에틸-3-메틸이미다졸륨 트리시아노메타나이드(1-Ethyl-3-methylimidazolium Tricyanomethanide: EMIM-TCM), 1-에틸-3-메틸이미다졸륨 테트라시아노보레이트(1-ethyl-3-methylimidazolium tetracyanoborate: EMIM-TCB), 1-에틸-3-메틸이미다졸륨 메틸 설페이트(1-ethyl-3-methylimidazolium methyl sulfate: EMIM-SO4), 디에틸메틸(2-메톡시에틸)암모늄 테트라프루오로보레이트(diethylmethyl(2-methoxyethyl)ammonium tetrafluoroborate: DMIM-BF4), 디에틸메틸(2-메톡시에틸)암모늄 비스(트리플루오로메틸설포닐) 이미드)(diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide): DMIM-TFSI), 1-옥틸-3-메틸이미다졸륨 비스(트리플루오르메틸 술포닐)이미드(1-Octyl-3-methylimidazorium bis(trifluoromethyl sulfonyl)imide: OMIM-TFSI)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있고, 바람직하게는 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4), 1-부틸-3-메틸이미다졸리움 헥사플루오로포스페이트(1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF6), 1-부틸-3-메틸이미다졸륨 비스(트리플루오로메틸설포닐) 이미드(1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide: BMIM-TFSI)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있고, 더욱 바람직하게는 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4)을 포함할 수 있다.The imidazolium-based ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF 4 ), 1-butyl-3-methylimidazolium hexafluoro Rophosphate (1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF 6 ), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) ) imide: BMIM-TFSI), 1-ethyl-3-methylimidazolium tetrafluoroborate (1-ethyl-3-methylimidazolium tetrafluoroborate: EMIM-BF 4 ), 1-ethyl-3-methylimidazolium bis ( Trifluoromethylsulfonyl) imide (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: EMIM-TFSI), 1-ethyl-3-methylimidazolium tricyanomethanide (1-Ethyl-3-methylimidazolium) Tricyanomethanide: EMIM-TCM), 1-ethyl-3-methylimidazolium tetracyanoborate (1-ethyl-3-methylimidazolium tetracyanoborate: EMIM-TCB), 1-ethyl-3-methylimidazolium methyl sulfate (1 -ethyl-3-methylimidazolium methyl sulfate: EMIM-SO 4 ), diethylmethyl(2-methoxyethyl)ammonium tetrafluoroborate: DMIM-BF 4 ), diethylmethyl (2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide) (diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide): DMIM-TFSI), 1-octyl-3-methylimidazolium Bis(trifluorime tyl sulfonyl) imide (1-Octyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide: OMIM-TFSI) may include at least one selected from the group consisting of, preferably 1-butyl-3-methyl Midazolium tetrafluoroborate (1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF 4 ), 1-Butyl-3-methylimidazolium hexafluorophosphate (1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF 6) ), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide: BMIM-TFSI) at least one selected from the group consisting of It may include, and more preferably, 1-butyl-3-methylimidazolium tetrafluoroborate (1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF 4 ) may be included.

상기 피리디늄계 이온성 액체는 에틸 피리디늄염이나 부틸피리디늄염, 헥실 피리디늄염 등으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다. 구체적으로는, 상기 에틸 피리디늄염으로서는, 1-에틸 피리디늄 브로마이드, 1-에틸 피리디늄 클로라이드를 포함할 수 있다. 상기 부틸 피리디늄염으로서는, 1-부틸 피리디늄 브로마이드, 1-부틸 피리디늄 클로라이드, 1-부틸 피리디늄 헥사플루오로 인산염, 1-부틸 피리디늄 테트라플루오로 붕산염, 1-부틸 피리디늄트리플루오로메탄 설폰산염 등을 포함할 수 있다. 상기 헥실 피리디늄염으로서는, 1-헥실 피리디늄 브로마이드, 1-헥실 피리디늄 클로라이드, 1-헥실 피리디늄 헥사플루오로 인산염, 1-헥실 피리디늄 테트라플루오로 붕산염, 1-헥실 피리디늄 트리플루오로메탄 설폰산염 등을 포함할 수 있다.The pyridinium-based ionic liquid may include at least one selected from the group consisting of ethyl pyridinium salt, butyl pyridinium salt, hexyl pyridinium salt, and the like. Specifically, the ethyl pyridinium salt may include 1-ethyl pyridinium bromide and 1-ethyl pyridinium chloride. Examples of the butyl pyridinium salt include 1-butyl pyridinium bromide, 1-butyl pyridinium chloride, 1-butyl pyridinium hexafluoro phosphate, 1-butyl pyridinium tetrafluoroborate, and 1-butyl pyridinium trifluoromethane. sulfonates and the like. Examples of the hexyl pyridinium salt include 1-hexyl pyridinium bromide, 1-hexyl pyridinium chloride, 1-hexyl pyridinium hexafluorophosphate, 1-hexyl pyridinium tetrafluoroborate, and 1-hexyl pyridinium trifluoromethane. sulfonates and the like.

상기 미정제 탄소나노튜브는 단일벽 탄소나노튜브, 또는 다중벽 탄소나노튜브로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The crude carbon nanotubes may include at least one selected from the group consisting of single-walled carbon nanotubes or multi-walled carbon nanotubes.

상기 불순물이 금속, 비정질 탄소, 흑연, 탄소 나노입자 및 할로겐 원소로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The impurities may include at least one selected from the group consisting of metal, amorphous carbon, graphite, carbon nanoparticles, and a halogen element.

상기 금속이 Ni, Co, Cu, Fe, Mg, Pd, Al, Si, 이들의 혼합물 및 이들의 산화물로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The metal may include at least one selected from the group consisting of Ni, Co, Cu, Fe, Mg, Pd, Al, Si, mixtures thereof, and oxides thereof.

다음으로, 상기 분산용액에 초음파를 조사한다(단계 b).Next, ultrasonic waves are irradiated to the dispersion solution (step b).

좀 더 자세히 설명하면, 단계 (b)가 상기 분산용액에 초음파를 조사하여 상기 미정제 탄소나노튜브에 포함된 상기 불순물을 분리시키는 단계;일 수 있다.In more detail, step (b) may be a step of separating the impurities contained in the crude carbon nanotubes by irradiating the dispersion solution with ultrasonic waves.

상기 분산용액에 초음파를 조사함으로써, 탄소나노튜브와 불순물(금속 나노촉매 등)의 결합이 끊어질 수 있다.By irradiating ultrasonic waves to the dispersion solution, the bond between the carbon nanotubes and impurities (metal nanocatalysts, etc.) may be broken.

단계 (b)에서 상기 초음파를 0.5 내지 5시간 동안 조사할 수 있다. In step (b), the ultrasonic wave may be irradiated for 0.5 to 5 hours.

단계 (b)에서 상기 초음파를 10 내지 150 kHz의 주파수에서 조사할 수 있다. In step (b), the ultrasonic wave may be irradiated at a frequency of 10 to 150 kHz.

단계 (b)에서 상기 초음파를 10 내지 300 W의 세기로 조사할 수 있다. In step (b), the ultrasonic wave may be irradiated with an intensity of 10 to 300 W.

단계 (b)가 단수회 또는 복수회 수행될 수 있다.Step (b) may be performed singly or plural times.

마지막으로, 상기 초음파가 조사된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득한다(단계 c).Finally, a high-purity carbon nanotube in which the impurities are separated is obtained from the dispersion solution irradiated with ultrasonic waves (step c).

좀 더 자세히 설명하면, 단계 (c)가 상기 초음파가 조사된 분산용액을 원심분리 또는 필터링하여 상기 초음파가 조사된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;일 수 있다.More specifically, step (c) may be a step of centrifuging or filtering the dispersion solution irradiated with ultrasonic waves to obtain high-purity carbon nanotubes in which the impurities are separated from the dispersion solution irradiated with ultrasonic waves;

단계 (c)가 (c-1) 상기 초음파가 조사된 분산용액에 세정용매를 혼합하여 세정된 분산용액을 제조하는 단계; (c-2) 상기 세정된 분산용액을 필터링하여 상기 세정된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;를 포함할 수 있다.Step (c) is (c-1) preparing a washed dispersion solution by mixing a cleaning solvent with the dispersion solution irradiated with ultrasonic waves; (c-2) filtering the washed dispersion solution to obtain high-purity carbon nanotubes from which the impurities are separated from the washed dispersion solution;

단계 (c-1)이 단수회 또는 복수회 수행될 수 있다.Step (c-1) may be performed singly or plural times.

상기 세정용매가 아세톤, 알코올, 에탄올, 이소프로필알코올(IPA) 및 증류수로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The cleaning solvent may include at least one selected from the group consisting of acetone, alcohol, ethanol, isopropyl alcohol (IPA) and distilled water.

단계 (c-2)에서 상기 필터링이 진공상태에서 수행될 수 있다.In step (c-2), the filtering may be performed in a vacuum state.

단계 (c) 이후에, 상기 고순도 탄소나노튜브를 건조하는 단계 (d);를 추가로 포함할 수 있다.After step (c), drying the high-purity carbon nanotubes (d); may further include.

단계 (d)에서 상기 건조가 50 내지 300℃의 온도에서 수행될 수 있다. The drying in step (d) may be performed at a temperature of 50 to 300 ℃.

또한, 상기 탄소나노튜브의 정제방법에 따라 제조된 고순도 탄소나노튜브가 제공된다.In addition, there is provided a high-purity carbon nanotube manufactured according to the purification method of the carbon nanotube.

또한, 상기 고순도 탄소나노튜브를 포함하고, 터치스크린용 전극, 수퍼캐퍼시터용 전극, 이차전지용 양극, 수소저장소자, 및 센서로 이루어진 군으로부터 선택된 어느 하나를 포함하는 전자소자가 제공된다.In addition, there is provided an electronic device including the high-purity carbon nanotube and including any one selected from the group consisting of an electrode for a touch screen, an electrode for a supercapacitor, a cathode for a secondary battery, a hydrogen storage device, and a sensor.

[실시예] [Example]

이하, 실시예를 통하여 본 발명을 더욱 상세하게 설명한다. 그러나 이는 예시를 위한 것으로서 이에 의하여 본 발명의 범위가 한정되는 것은 아니다. Hereinafter, the present invention will be described in more detail through examples. However, this is for illustrative purposes, and the scope of the present invention is not limited thereto.

실시예 1: 초음파를 이용하여 정제된 고순도 SWCNTs Example 1: High-purity SWCNTs purified using ultrasound

이온성 액체 [BMIM][BF4] 15ml에 불순물을 포함하는 미정제 탄소나노튜브(나노솔루션, SWCNT) 1g을 투입하고, 상온에서 300rpm으로 10분 동안 교반시켜 분산용액을 제조하였다. 상기 분산용액을 Multi-Frequency Sonoreactor 장치(다중주파수 초음파 반응기, SRF-2(일본))를 이용하여 주파수 75kHz, 공정 파워 100W 조건으로 2시간 동안 초음파를 조사하였다. 1 g of crude carbon nanotube (nanosolution, SWCNT) containing impurities was added to 15 ml of the ionic liquid [BMIM] [BF 4 ], and stirred at room temperature at 300 rpm for 10 minutes to prepare a dispersion solution. The dispersion solution was irradiated with ultrasonic waves for 2 hours at a frequency of 75 kHz and a process power of 100 W using a Multi-Frequency Sonoreactor device (multi-frequency ultrasonic reactor, SRF-2 (Japan)).

진공 필터링 장치를 통해 상기 초음파가 조사된 분산용액으로부터 불순물이 분리된 고순도 탄소나노튜브 (SWCNT) 소재만을 수득하였는데, 구체적으로 진공 필터링 장치의 상부 플라스크에 상기 초음파가 조사된 분산용액을 투입하고, 아세톤과 에탄올을 이용해 세정공정을 진행하였다. 여기서 아세톤은 이온성 액체([BMIM][BF4])를 1차적으로 제거하기 위한 용도로 사용되며, 에탄올은 잔류 아세톤과 이온성 액체를 제거하기 위해 사용되었다. 상기 세정공정이 수행된 분산용액은 진공 필터링 장치의 상부 플라스크와 하부 플라스크 사이에 있는 membrane filter로 인해 이온성 액체([BMIM][BF4]), 세정용매(아세톤, 에탄올) 및 분리된 금속 불순물(nanometer scale)이 하부로 통과되고, 상대적으로 입자 크기가 큰 탄소나노튜브 (SWCNT) 소재만 필터링시켜 정제된 고순도 탄소나노튜브를 수득하였다. 이때 용매(이온성 액체, 세정용매 등) 및 금속 불순물을 빠르게 배출시키기 위해 상/하부 플라스크 사이에 진공 pump를 연결하여 필터링하였다. Only high-purity carbon nanotube (SWCNT) material in which impurities are separated from the dispersion solution irradiated with ultrasonic waves through a vacuum filtering device was obtained. Specifically, the dispersion solution irradiated with ultrasonic waves was put into the upper flask of the vacuum filtering device, and acetone The washing process was performed using ethanol and ethanol. Here, acetone is used to primarily remove the ionic liquid ([BMIM][BF 4 ]), and ethanol is used to remove residual acetone and the ionic liquid. The dispersion solution subjected to the cleaning process is an ionic liquid ([BMIM][BF 4 ]), a cleaning solvent (acetone, ethanol) and metal impurities separated by a membrane filter between the upper and lower flasks of the vacuum filtering device. (nanometer scale) was passed to the bottom, and only a carbon nanotube (SWCNT) material having a relatively large particle size was filtered to obtain a purified high-purity carbon nanotube. At this time, in order to quickly discharge the solvent (ionic liquid, cleaning solvent, etc.) and metal impurities, a vacuum pump was connected between the upper and lower flasks for filtering.

이후, 상기 고순도 탄소나노튜브 표면에 존재하는 불순물들을 완벽히 제거하기 위해 아세톤, 알코올 세정 공정을 2~3회 정도 반복해서 실시하였다.Thereafter, in order to completely remove impurities present on the surface of the high-purity carbon nanotubes, the acetone and alcohol cleaning process was repeated 2-3 times.

비교예 1: 불순물을 포함하는 미정제 탄소나노튜브(Raw SWCNTs)Comparative Example 1: Crude carbon nanotubes containing impurities (Raw SWCNTs)

불순물을 포함하는 미정제 탄소나노튜브(나노솔루션, SWCNT)를 사용하였다.Crude carbon nanotubes (nanosolution, SWCNT) containing impurities were used.

[시험예][Test Example]

시험예 1: 초음파 공정 수행여부에 따른 탄소나노튜브의 SEM 분석Test Example 1: SEM analysis of carbon nanotubes according to whether ultrasonic process was performed

도 2a는 비교예 1 및 도 2b는 실시예 1의 SEM 이미지이다.2A is a SEM image of Comparative Example 1 and FIG. 2B is an SEM image of Example 1.

도 2a 및 2b에 따르면, 이온성 액체 기반 초음파 공정 수행여부에 따라 탄소나노튜브(SWCNT)에 대한 SEM 분석을 통해 SWCNT 내 잔류하는 금속 불순물 여부를 확인하였고, 비교예 1(정제 전 샘플)은 탄소나노튜브 매트릭스(Matrix) 내 국부적으로 다른 형상의 물질들이 분포하고 있는 것을 확인할 수 있었다. 그러나 실시예 1(정제 후 샘플)은 전체적으로 탄소나노튜브의 결정 형상만을 보여주고 있으며, 금속 불순물로 여겨지는 물질들은 대부분 제거되었음 확인할 수 있었다.According to FIGS. 2a and 2b, whether or not metal impurities remaining in SWCNTs were confirmed through SEM analysis of carbon nanotubes (SWCNTs) depending on whether an ionic liquid-based ultrasonic process was performed, and Comparative Example 1 (sample before purification) was carbon It was confirmed that materials of different shapes were locally distributed in the nanotube matrix. However, Example 1 (the sample after purification) showed only the crystal shape of the carbon nanotube as a whole, and it was confirmed that most of the materials considered to be metal impurities were removed.

시험예 2: 초음파 공정 수행여부에 따른 탄소나노튜브의 금속 원소함량 비교Test Example 2: Comparison of metal element content of carbon nanotubes according to whether or not ultrasonic process was performed

하기 표 1은 비교예 1 및 실시예 1의 SEM-EDS 조성 분석결과로서, 각각의 원소 함량을 기재하였다.Table 1 below is the SEM-EDS composition analysis result of Comparative Example 1 and Example 1, and the content of each element is described.

ElementElement 조성 함량 (wt.%)Composition content (wt.%) 비교예 1 (정제 전 SWCNT)Comparative Example 1 (SWCNT before purification) 실시예 1 (정제 후 SWCNT)Example 1 (SWCNT after purification) CC 66.366.3 95.895.8 FF 0.00.0 0.30.3 FeFe 15.515.5 1.81.8 CoCo 9.99.9 1.21.2 NiNi 8.38.3 0.90.9 TotalTotal 100.0100.0 100.0100.0

표 1에 따르면, 초음파 공정 수행여부에 따라 SWCNT 내 잔류하는 금속 불순물 여부를 정량적으로 분석하기 위해 EDS 조성 분석을 수행하였고, 비교예 1(정제 전 샘플)은 Fe, Co, Ni 금속의 함량이 각각 15.5, 9.9, 8.3 wt.%의 함량을 나타내어 탄소나노튜브 내 금속 함량이 30% 이상인 것을 확인할 수 있었다. 반면, 실시예 1(정제 후 샘플)은 금속 원소들의 함량이 대폭적으로 감소하였으며, Fe, Co, Ni 금속의 함량이 각각 1.8%, 1.2%, 0.9%임을 확인할 수 있었다. 또한, 초음파 정제 용매인 이온성 액체(BMIM BF4)의 SWCNT 내 잔류여부를 확인하기 위해 "F" 함량을 확인한 결과 0.3 wt.%의 함량을 보임으로써, 정제 용매인 이온성 액체 또한 대부분 제거되었음을 확인할 수 있었다.According to Table 1, EDS composition analysis was performed to quantitatively analyze whether or not metal impurities remained in the SWCNT depending on whether the ultrasonic process was performed, and Comparative Example 1 (sample before purification) showed Fe, Co, and Ni metal contents, respectively. It was confirmed that the metal content in the carbon nanotubes was 30% or more by showing the contents of 15.5, 9.9, and 8.3 wt.%. On the other hand, in Example 1 (the sample after purification), the content of metal elements was significantly reduced, and it was confirmed that the content of Fe, Co, and Ni metals were 1.8%, 1.2%, and 0.9%, respectively. In addition, as a result of checking the "F" content to check whether the ionic liquid (BMIM BF 4 ), which is the ultrasonic purification solvent, remains in SWCNT, the content of 0.3 wt.% was shown, indicating that most of the ionic liquid as the purification solvent was also removed. could check

시험예 3: 라만 스펙트라 분석Test Example 3: Raman spectra analysis

도 3은 비교예 1(Raw SWCNT) 및 실시예 1(Ultrasonicated SWCNT at [BMIM][BF4])의 라만 스펙트라 분석 그래프로, 하기 표 2에 분석결과를 기재하였다.3 is a Raman spectra analysis graph of Comparative Example 1 (Raw SWCNT) and Example 1 (Ultrasonicated SWCNT at [BMIM][BF 4 ]), and the analysis results are described in Table 2 below.

Scattering modeScattering mode 비교예 1(Raw SWCNT)Comparative Example 1 (Raw SWCNT) 실시예 1(Ultrasonicated SWCNT at [BMIM][BF4])Example 1 (Ultrasonicated SWCNT at [BMIM][BF 4 ]) RBM (cm-1)RBM (cm -1 ) 168168 182182 SWCNT diameter (nm)SWCNT diameter (nm) 1.51.5 1.41.4 D (cm-1)D (cm -1 ) 13451345 13421342 G (cm-1)G (cm -1 ) 1565/15971565/1597 1567/15971567/1597 G'(cm-1)G' (cm -1 ) 26792679 26832683 Intensity
(cps)
Intensity
(cps)
DD 257257 1919
GG 19251925 328328 Intensity ratio (G/D)Intensity ratio (G/D) 7.57.5 17.317.3

* Radial breathing mode (RBM) corresponds to radial expansion-contraction of the nanotube VRBM = 234/d + 10 for SWCNT (V: Raman frequency, d: nanotube diameter (nm))* Radial breathing mode (RBM) corresponds to radial expansion-contraction of the nanotube VRBM = 234/d + 10 for SWCNT (V: Raman frequency, d: nanotube diameter (nm))

* D mode: all graphite-like carbons and structural defects* D mode: all graphite-like carbons and structural defects

* G mode: planar vibration of carbon atoms* G mode: planar vibration of carbon atoms

* G'mode: second scattering mode after the G mode* G'mode: second scattering mode after the G mode

도 3 및 표 2에 따르면, “G” peak의 강도가 높을수록 탄소나노튜브의 결정성이 우수하며, “D” peak 높을수록 불순물 및 구조적 결함이 큰 것을 의미하고, 일반적으로 G/D 비율이 높을수록 탄소나노튜브 소재의 결정성이 우수함을 나타낸다. 미정제 탄소나노튜브인 비교예 1의 G/D 값은 7.5, 초음파 공정을 통해 정제한 실시예 1의 G/D 값은 17.3으로 나타났다. 이는 초음파 공정을 통해 탄소나노튜브에 존재하는 비정질 탄소 및 구조적 결함 성분(금속 불순물 등)이 제거되어 실시예 1에 따른 정제된 고순도 탄소나노튜브의 결정성이 비교예 1에 비해 극적으로 향상되었음을 확인하였다.According to FIG. 3 and Table 2, the higher the intensity of the “G” peak, the better the crystallinity of the carbon nanotube, and the higher the “D” peak, the greater the impurities and structural defects. The higher the value, the better the crystallinity of the carbon nanotube material. The G/D value of Comparative Example 1, which is a crude carbon nanotube, was 7.5, and the G/D value of Example 1 purified through an ultrasonic process was 17.3. This confirmed that the crystallinity of the purified high-purity carbon nanotube according to Example 1 was dramatically improved compared to Comparative Example 1 by removing the amorphous carbon and structural defect components (metal impurities, etc.) present in the carbon nanotube through the ultrasonic process. did.

이상, 본 발명의 바람직한 실시예를 들어 상세하게 설명하였으나, 본 발명은 상기 실시예에 한정되지 않으며, 본 발명의 기술적 사상의 범위 내에서 당 분야에 통상의 지식을 가진 자에 의하여 여러 가지 변형이 가능하다.As mentioned above, although preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various modifications may be made by those of ordinary skill in the art within the scope of the technical spirit of the present invention. It is possible.

Claims (20)

(a) 불순물을 포함하는 미정제 탄소나노튜브를 이온성 액체에 분산시켜 분산용액을 제조하는 단계;
(b) 상기 분산용액에 초음파를 조사하는 단계; 및
(c) 상기 초음파가 조사된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;를
포함하는 탄소나노튜브의 정제방법.
(a) preparing a dispersion solution by dispersing the crude carbon nanotubes containing impurities in an ionic liquid;
(b) irradiating ultrasonic waves to the dispersion solution; and
(c) obtaining high-purity carbon nanotubes in which the impurities are separated from the dispersion solution irradiated with ultrasonic waves;
A method for purifying carbon nanotubes comprising
제1항에 있어서,
상기 이온성 액체가 지방족계 이온성 액체, 이미다졸륨계 이온성 액체 및 피리디늄계 이온성 액체로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
The method for purifying carbon nanotubes, wherein the ionic liquid comprises at least one selected from the group consisting of an aliphatic ionic liquid, an imidazolium-based ionic liquid, and a pyridinium-based ionic liquid.
제2항에 있어서,
상기 이온성 액체가 이미다졸륨계 이온성 액체를 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
3. The method of claim 2,
The method for purifying carbon nanotubes, characterized in that the ionic liquid includes an imidazolium-based ionic liquid.
제3항에 있어서,
상기 이미다졸륨계 이온성 액체가 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4), 1-부틸-3-메틸이미다졸리움 헥사플루오로포스페이트(1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF6), 1-부틸-3-메틸이미다졸륨 비스(트리플루오로메틸설포닐) 이미드(1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide: BMIM-TFSI), 1-에틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-ethyl-3-methylimidazolium tetrafluoroborate: EMIM-BF4), 1-에틸-3-메틸이미다졸륨비스(트리플루오로메틸설포닐) 이미드(1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: EMIM-TFSI), 1-에틸-3-메틸이미다졸륨 트리시아노메타나이드(1-Ethyl-3-methylimidazolium Tricyanomethanide: EMIM-TCM), 1-에틸-3-메틸이미다졸륨 테트라시아노보레이트(1-ethyl-3-methylimidazolium tetracyanoborate: EMIM-TCB), 1-에틸-3-메틸이미다졸륨 메틸 설페이트(1-ethyl-3-methylimidazolium methyl sulfate: EMIM-SO4), 디에틸메틸(2-메톡시에틸)암모늄 테트라프루오로보레이트(diethylmethyl(2-methoxyethyl)ammonium tetrafluoroborate: DMIM-BF4), 디에틸메틸(2-메톡시에틸)암모늄 비스(트리플루오로메틸설포닐) 이미드)(diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide): DMIM-TFSI), 1-옥틸-3-메틸이미다졸륨 비스(트리플루오르메틸 술포닐)이미드(1-Octyl-3-methylimidazorium bis(trifluoromethyl sulfonyl)imide: OMIM-TFSI)으로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
4. The method of claim 3,
The imidazolium-based ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate (1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF 4 ), 1-butyl-3-methylimidazolium hexafluoro Rophosphate (1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF 6 ), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) ) imide: BMIM-TFSI), 1-ethyl-3-methylimidazolium tetrafluoroborate (1-ethyl-3-methylimidazolium tetrafluoroborate: EMIM-BF 4 ), 1-ethyl-3-methylimidazolium bis ( Trifluoromethylsulfonyl) imide (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: EMIM-TFSI), 1-ethyl-3-methylimidazolium tricyanomethanide (1-Ethyl-3-methylimidazolium) Tricyanomethanide: EMIM-TCM), 1-ethyl-3-methylimidazolium tetracyanoborate (1-ethyl-3-methylimidazolium tetracyanoborate: EMIM-TCB), 1-ethyl-3-methylimidazolium methyl sulfate (1 -ethyl-3-methylimidazolium methyl sulfate: EMIM-SO 4 ), diethylmethyl(2-methoxyethyl)ammonium tetrafluoroborate: DMIM-BF 4 ), diethylmethyl (2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide) (diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide): DMIM-TFSI), 1-octyl-3-methylimidazolium Bis(trifluorime A method for purifying carbon nanotubes, comprising at least one selected from the group consisting of tyl sulfonyl) imide (1-Octyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide: OMIM-TFSI).
제4항에 있어서,
상기 이미다졸륨계 이온성 액체가 1-부틸-3-메틸이미다졸륨 테트라플루오로보레이트(1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF4), 1-부틸-3-메틸이미다졸리움 헥사플루오로포스페이트(1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF6), 1-부틸-3-메틸이미다졸륨 비스(트리플루오로메틸설포닐) 이미드(1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide: BMIM-TFSI)으로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
5. The method of claim 4,
The imidazolium-based ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate (1-butyl-3-methylimidazolium tetrafluoroborate: BMIM-BF 4 ), 1-butyl-3-methylimidazolium hexafluoro Rophosphate (1-Butyl-3-methylimidazolium hexafluorophosphate: BMIM-PF 6 ), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) ) imide: A carbon nanotube purification method comprising at least one selected from the group consisting of (BMIM-TFSI).
제1항에 있어서,
상기 미정제 탄소나노튜브는 단일벽 탄소나노튜브, 또는 다중벽 탄소나노튜브로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
The crude carbon nanotube is a carbon nanotube purification method, characterized in that it comprises at least one selected from the group consisting of single-walled carbon nanotubes or multi-walled carbon nanotubes.
제1항에 있어서,
상기 불순물이 금속, 비정질 탄소, 흑연, 탄소 나노입자 및 할로겐 원소로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
The method for purifying carbon nanotubes, wherein the impurities include at least one selected from the group consisting of metals, amorphous carbon, graphite, carbon nanoparticles, and halogen elements.
제7항에 있어서,
상기 금속이 Ni, Co, Cu, Fe, Mg, Pd, Al, Si, 이들의 혼합물 및 이들의 산화물로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
8. The method of claim 7,
The method for purifying carbon nanotubes, wherein the metal comprises at least one selected from the group consisting of Ni, Co, Cu, Fe, Mg, Pd, Al, Si, mixtures thereof, and oxides thereof.
제1항에 있어서,
단계 (b)가 상기 분산용액에 초음파를 조사하여 상기 미정제 탄소나노튜브에 포함된 상기 불순물을 분리시키는 단계;인 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
Step (b) is a step of separating the impurities contained in the crude carbon nanotubes by irradiating the dispersion solution with ultrasonic waves; carbon nanotube purification method, characterized in that.
제1항에 있어서,
단계 (b)에서 상기 초음파를 0.5 내지 5시간 동안 조사하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
A method for purifying carbon nanotubes, characterized in that irradiating the ultrasonic waves for 0.5 to 5 hours in step (b).
제1항에 있어서,
단계 (b)에서 상기 초음파를 10 내지 150 kHz의 주파수에서 조사하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
A method for purifying carbon nanotubes, characterized in that in step (b), the ultrasonic wave is irradiated at a frequency of 10 to 150 kHz.
제1항에 있어서,
단계 (b)에서 상기 초음파를 10 내지 300 W의 세기로 조사하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
A method of purifying carbon nanotubes, characterized in that irradiating the ultrasonic waves with an intensity of 10 to 300 W in step (b).
제1항에 있어서,
단계 (c)가
상기 초음파가 조사된 분산용액을 원심분리 또는 필터링하여 상기 초음파가 조사된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;인 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
step (c) is
centrifuging or filtering the dispersion solution irradiated with ultrasonic waves to obtain high-purity carbon nanotubes in which the impurities are separated from the dispersion solution irradiated with ultrasonic waves;
제1항에 있어서,
단계 (c)가
(c-1) 상기 초음파가 조사된 분산용액에 세정용매를 혼합하여 세정된 분산용액을 제조하는 단계;
(c-2) 상기 세정된 분산용액을 필터링하여 상기 세정된 분산용액으로부터 상기 불순물이 분리된 고순도 탄소나노튜브를 수득하는 단계;를 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
step (c) is
(c-1) preparing a washed dispersion solution by mixing a cleaning solvent with the dispersion solution irradiated with ultrasonic waves;
(c-2) filtering the washed dispersion solution to obtain high-purity carbon nanotubes from which the impurities are separated from the washed dispersion solution;
제14항에 있어서,
단계 (c-2)에서 상기 필터링이 진공상태에서 수행되는 것을 특징으로 하는 탄소나노튜브의 정제방법.
15. The method of claim 14,
A method for purifying carbon nanotubes, characterized in that the filtering in step (c-2) is performed in a vacuum state.
제14항에 있어서,
상기 세정용매가 아세톤, 알코올, 에탄올, 이소프로필알코올(IPA) 및 증류수로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
15. The method of claim 14,
The method for purifying carbon nanotubes, wherein the cleaning solvent comprises at least one selected from the group consisting of acetone, alcohol, ethanol, isopropyl alcohol (IPA) and distilled water.
제1항에 있어서,
단계 (c) 이후에,
상기 고순도 탄소나노튜브를 건조하는 단계 (d);를 추가로 포함하는 것을 특징으로 하는 탄소나노튜브의 정제방법.
According to claim 1,
After step (c),
The purification method of carbon nanotubes, characterized in that it further comprises; (d) drying the high-purity carbon nanotubes.
제17항에 있어서,
단계 (d)에서 상기 건조가 50 내지 300℃의 온도에서 수행되는 것을 특징으로 하는 탄소나노튜브의 정제방법.
18. The method of claim 17,
A method for purifying carbon nanotubes, characterized in that the drying in step (d) is performed at a temperature of 50 to 300 °C.
제1항의 탄소나노튜브의 정제방법에 따라 제조된 고순도 탄소나노튜브.A high-purity carbon nanotube manufactured according to the carbon nanotube purification method of claim 1. 제19항의 고순도 탄소나노튜브를 포함하고,
터치스크린용 전극, 수퍼캐퍼시터용 전극, 이차전지용 양극, 수소저장소자, 및 센서로 이루어진 군으로부터 선택된 어느 하나를 포함하는 전자소자.
Including the high-purity carbon nanotubes of claim 19,
An electronic device comprising any one selected from the group consisting of an electrode for a touch screen, an electrode for a supercapacitor, an anode for a secondary battery, a hydrogen storage device, and a sensor.
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