KR20230071243A - Method for preparing a core-shell structured composite coated with graphene on the surface of hydrophobic particles using a kneading method, and a core-shell structured composite prepared therefrom - Google Patents
Method for preparing a core-shell structured composite coated with graphene on the surface of hydrophobic particles using a kneading method, and a core-shell structured composite prepared therefrom Download PDFInfo
- Publication number
- KR20230071243A KR20230071243A KR1020210157220A KR20210157220A KR20230071243A KR 20230071243 A KR20230071243 A KR 20230071243A KR 1020210157220 A KR1020210157220 A KR 1020210157220A KR 20210157220 A KR20210157220 A KR 20210157220A KR 20230071243 A KR20230071243 A KR 20230071243A
- Authority
- KR
- South Korea
- Prior art keywords
- graphene
- graphene oxide
- core
- carbon
- solution
- Prior art date
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 256
- 229910021389 graphene Inorganic materials 0.000 title claims abstract description 181
- 239000002131 composite material Substances 0.000 title claims abstract description 63
- 239000002245 particle Substances 0.000 title claims abstract description 61
- 230000002209 hydrophobic effect Effects 0.000 title claims abstract description 57
- 239000011258 core-shell material Substances 0.000 title claims abstract description 37
- 238000004898 kneading Methods 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 20
- 239000011149 active material Substances 0.000 claims abstract description 52
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 41
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000007921 spray Substances 0.000 claims abstract description 21
- 238000002156 mixing Methods 0.000 claims abstract description 18
- 238000001694 spray drying Methods 0.000 claims abstract description 12
- 239000002904 solvent Substances 0.000 claims abstract description 11
- 229910002804 graphite Inorganic materials 0.000 claims description 48
- 239000010439 graphite Substances 0.000 claims description 48
- 239000006185 dispersion Substances 0.000 claims description 29
- 229910052799 carbon Inorganic materials 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 13
- 239000002041 carbon nanotube Substances 0.000 claims description 13
- 239000003125 aqueous solvent Substances 0.000 claims description 10
- 239000003638 chemical reducing agent Substances 0.000 claims description 7
- 230000003993 interaction Effects 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 6
- 239000006229 carbon black Substances 0.000 claims description 6
- 229910021385 hard carbon Inorganic materials 0.000 claims description 6
- 229910044991 metal oxide Inorganic materials 0.000 claims description 6
- 150000004706 metal oxides Chemical class 0.000 claims description 6
- 229910021382 natural graphite Inorganic materials 0.000 claims description 6
- 229910021384 soft carbon Inorganic materials 0.000 claims description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 239000001257 hydrogen Substances 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 239000000243 solution Substances 0.000 description 55
- 239000000843 powder Substances 0.000 description 36
- 239000000463 material Substances 0.000 description 30
- 230000005661 hydrophobic surface Effects 0.000 description 12
- 238000002411 thermogravimetry Methods 0.000 description 12
- 239000011248 coating agent Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- 239000011812 mixed powder Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 239000003792 electrolyte Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000007086 side reaction Methods 0.000 description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 239000012153 distilled water Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 239000005456 alcohol based solvent Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000005979 thermal decomposition reaction Methods 0.000 description 3
- 230000004580 weight loss Effects 0.000 description 3
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 1
- 241000233805 Phoenix Species 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- -1 diversity in size Substances 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229940035429 isobutyl alcohol Drugs 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 150000003463 sulfur Chemical class 0.000 description 1
- 238000002230 thermal chemical vapour deposition Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/02—Making microcapsules or microballoons
- B01J13/04—Making microcapsules or microballoons by physical processes, e.g. drying, spraying
- B01J13/043—Drying and spraying
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/194—After-treatment
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/32—Carbon-based
- H01G11/38—Carbon pastes or blends; Binders or additives therein
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
Abstract
본 발명은 반죽법을 이용한 소수성 입자 표면에 그래핀이 코팅된 코어-쉘 복합체의 제조방법, 이로부터 제조되는 코어-쉘 복합체에 관한 것이다.
이러한 본 발명은, 소수성 입자와 알코올을 혼합하여 활물질 반죽을 제조하는 단계; 활물질 반죽과, 수계 용매 기반의 친수성 그래핀을 혼합하여 분무 용액을 제조하는 단계; 분무 용액을 분무 건조하여 소수성 입자의 표면에 친수성 그래핀이 코팅된 코어-쉘 복합체를 제조하는 단계;를 포함하는 것을 기술적 요지로 한다.The present invention relates to a method for preparing a core-shell composite in which graphene is coated on the surface of hydrophobic particles using a kneading method, and a core-shell composite prepared therefrom.
The present invention comprises the steps of preparing an active material dough by mixing hydrophobic particles and alcohol; preparing a spray solution by mixing active material kneading with hydrophilic graphene based on a water-based solvent; A step of spray drying the spray solution to prepare a core-shell composite in which hydrophilic graphene is coated on the surface of the hydrophobic particles;
Description
본 발명은 반죽법을 이용한 소수성 입자 표면에 그래핀이 코팅된 코어-쉘 복합체의 제조방법, 이로부터 제조되는 코어-쉘 복합체에 관한 것이다.The present invention relates to a method for preparing a core-shell composite in which graphene is coated on the surface of hydrophobic particles using a kneading method, and a core-shell composite prepared therefrom.
이차전지는 적용 분야에 따라 전극 소재가 구별되고, 전극 소재의 표면 특성, 크기의 다양성, 활물질, 도전재 및 바인더 등의 부반응으로 인하여 셀 성능 저하가 야기되고 있다. 예를 들면 실리콘 기반 고용량 음극재의 경우 리튬 이온의 흡수 및 저장 시 결정 구조의 변화로 인해 약 400% 이상의 부피 변화가 발생되고, 계속된 부피 변화로 인해 실리콘의 구조가 와해되는 현상이 야기되므로, 초기 효율 및 사이클 특성이 저하되기 때문에 이차전지의 가역성을 향상시키면서 고용량을 유지하는 기술이 필수적이다.In secondary batteries, electrode materials are distinguished according to application fields, and cell performance is degraded due to side reactions such as surface characteristics of electrode materials, diversity in size, active materials, conductive materials, and binders. For example, in the case of a silicon-based high-capacity negative electrode material, a volume change of about 400% or more occurs due to a change in the crystal structure during absorption and storage of lithium ions, and the continued volume change causes the collapse of the silicon structure. Since efficiency and cycle characteristics are deteriorated, a technique for maintaining high capacity while improving reversibility of a secondary battery is essential.
이를 위해 구조적 안정성 및 표면 안정화, 전해액과의 함침 특성, 계면 반응에서의 저항 감소 등의 성능을 향상시키기 위해 활물질에 열화학기상증착법을 이용하여 탄소를 코팅하는 방법을 주로 이용하고 있다. 하지만 탄소 코팅의 경우 활물질 표면에 금속 촉매를 도입할 수 없기 때문에 결정성 저하 및 탄소층의 두께 조절이 어려운 단점이 있다.To this end, a method of coating carbon on an active material by using a thermal chemical vapor deposition method is mainly used to improve performance such as structural stability and surface stabilization, impregnation with electrolyte, and resistance reduction in interface reaction. However, in the case of carbon coating, it is difficult to reduce crystallinity and control the thickness of the carbon layer because it is impossible to introduce a metal catalyst to the surface of the active material.
표면에 탄소층을 코팅하지 않고 고용량의 활물질을 이차전지용 전극에 도입하는 것은 불가능하기 때문에 대부분 결함이 많은 탄소층을 활물질 표면에 성장시켜 사용하고 있다. 또한 대부분의 활물질의 경우 탄소 코팅된 금속 및 금속산화물, 흑연, 탄소나노튜브, 카본블랙, 그래핀, 소프트 카본, 하드 카본, 황 복합체 등과 같이 표면에 탄소로 이루어져 있기 때문에 전기화학적인 특성 향상을 위해 전기전도성이 우수하고, 전해액과 부반응을 야기시키지 않는 물질을 도포하는 공정은 중요하다.Since it is impossible to introduce a high-capacity active material into a secondary battery electrode without coating a carbon layer on the surface, a carbon layer with many defects is grown on the surface of the active material. In addition, since most active materials are composed of carbon on the surface, such as carbon-coated metals and metal oxides, graphite, carbon nanotubes, carbon black, graphene, soft carbon, hard carbon, and sulfur composites, A process of applying a material that has excellent electrical conductivity and does not cause a side reaction with the electrolyte is important.
'그래핀-탄소나노튜브 복합체의 제조방법(공개번호: 10-2021-0128176)'에서는 산화그래핀을 환원시킨 그래핀과, 산처리된 탄소나노튜브를 용매 중에 분산시키고 분무 건조하여 그래핀-탄소나노튜브 복합체를 제조하는 방법을 개시하고 있다. 또한 '구겨진 형상의 그래핀-탄소나노튜브 복합체 제조방법, 이에 따라 제조된 그래핀-탄소나노튜브 복합체 및 이를 포함하는 슈퍼커패시터(10-1744122)'에서는 산 처리된 탄소나노튜브, 그래핀 옥사이드 및 용매를 혼합한 콜로이드 혼합용액을 분무 건조하고 열처리하여 그래핀-탄소나노튜브 복합체를 제조하는 방법을 개시하고 있다.In 'Method for Manufacturing Graphene-Carbon Nanotube Composite (Publication No.: 10-2021-0128176)', graphene obtained by reducing graphene oxide and acid-treated carbon nanotubes are dispersed in a solvent and spray-dried to obtain graphene-carbon nanotube composites. A method for preparing a carbon nanotube composite is disclosed. In addition, in 'Crumpled graphene-carbon nanotube composite manufacturing method, graphene-carbon nanotube composite produced thereby, and supercapacitor including the same (10-1744122)', acid-treated carbon nanotubes, graphene oxide and Disclosed is a method for preparing a graphene-carbon nanotube composite by spray drying and heat-treating a colloidal mixture solution in which a solvent is mixed.
하지만 활물질로 사용되는 탄소 소재의 표면은 소수성을 지녀 수계 용매 내에서 분산이 어려워서 산화그래핀이나 산화그래핀환원물과 같이 수계 분산된 용액 내에서의 분산 역시 용이하지 않기 때문에, 활물질과 산화그래핀 또는 산화그래핀환원물과 혼합될 때 상 분리 현상이 쉽게 발생되어 결국 전극 효율이 저하될 수 밖에 없는 문제점이 있으므로, 이를 해결해 보기 위한 연구가 절실히 요구되고 있는 실정이다.However, since the surface of the carbon material used as the active material is hydrophobic and difficult to disperse in an aqueous solvent, it is also difficult to disperse in an aqueous dispersed solution such as graphene oxide or graphene oxide reducing product, so the active material and graphene oxide Or, when mixed with a graphene oxide reducing material, phase separation easily occurs, resulting in a decrease in electrode efficiency. Therefore, research to solve this problem is urgently required.
본 발명은 상기한 문제점을 해소하기 위하여 발명된 것으로, 층 분리 현상이 발생되지 않도록 반죽법을 이용한 소수성 입자 표면에 그래핀이 코팅된 코어-쉘 복합체의 제조방법, 이로부터 제조되는 코어-쉘 복합체를 제공하는 것을 기술적 해결과제로 한다.The present invention was invented to solve the above problems, and a method for producing a core-shell composite in which graphene is coated on the surface of hydrophobic particles using a kneading method to prevent layer separation, and a core-shell composite prepared therefrom It is a technical solution to provide
상기의 기술적 과제를 해결하기 위하여 본 발명은, 소수성 입자와 알코올을 혼합하여 활물질 반죽을 제조하는 단계; 상기 활물질 반죽과, 수계 용매 기반의 친수성 그래핀을 혼합하여 분무 용액을 제조하는 단계; 및 상기 분무 용액을 분무 건조하여 상기 소수성 입자의 표면에 상기 친수성 그래핀이 코팅된 코어-쉘 복합체를 제조하는 단계;를 포함하는 것을 특징으로 하는, 반죽법을 이용한 소수성 입자 표면에 그래핀이 코팅된 코어-쉘 복합체의 제조방법을 제공한다.In order to solve the above technical problem, the present invention comprises the steps of preparing an active material dough by mixing hydrophobic particles and alcohol; preparing a spray solution by mixing the active material dough with hydrophilic graphene based on an aqueous solvent; and preparing a core-shell composite in which the surface of the hydrophobic particle is coated with the hydrophilic graphene by spray-drying the spray solution; graphene is coated on the surface of the hydrophobic particle using a kneading method It provides a method for preparing the core-shell composite.
본 발명에 있어서, 상기 소수성 입자는, 천연흑연, 인조흑연, 탄소나노튜브, 카본블랙, 탄소 코팅된 금속, 탄소 코팅된 금속산화물, 그래핀, 소프트 카본 및 하드 카본으로 이루어진 군에서 선택되는 1종 이상인 것을 특징으로 한다.In the present invention, the hydrophobic particles are one selected from the group consisting of natural graphite, artificial graphite, carbon nanotubes, carbon black, carbon-coated metals, carbon-coated metal oxides, graphene, soft carbon, and hard carbon. It is characterized by more than
본 발명에 있어서, 상기 친수성 그래핀은, 물(H2O)을 포함하는 수계 용매에 산화그래핀 또는 산화그래핀환원물이 분산되어 형성되는 그래핀 용액인 것을 특징으로 한다.In the present invention, the hydrophilic graphene is characterized in that it is a graphene solution formed by dispersing graphene oxide or a graphene oxide reduced product in an aqueous solvent containing water (H 2 O).
본 발명에 있어서, 상기 그래핀 용액은, 그래파이트를 산화시킨 후 분산 및 박리하여 형성되는 산화그래핀을 양이온-파이 상호작용을 통해 형성되는 산화그래핀 분산 용액인 것을 특징으로 한다.In the present invention, the graphene solution is characterized in that it is a graphene oxide dispersion solution formed through cation-pi interaction of graphene oxide formed by oxidizing graphite and then dispersing and exfoliating it.
본 발명에 있어서, 상기 그래핀 용액은, 그래파이트를 산화시킨 후 분산 및 박리하여 형성되는 산화그래핀을 양이온-파이 상호작용을 통해 산화그래핀 분산 용액을 형성하고, 상기 산화그래핀 분산 용액에 환원제를 투입하여 환원시킨 산화그래핀환원물 분산 용액인 것을 특징으로 한다.In the present invention, the graphene solution is formed by oxidizing graphite and then dispersing and exfoliating graphene oxide through a cation-pi interaction to form a graphene oxide dispersion solution, and a reducing agent is added to the graphene oxide dispersion solution. It is characterized in that it is a graphene oxide reducing material dispersion solution reduced by adding.
본 발명에 있어서, 상기 분무 용액은, 상기 알코올과 상기 수계 용매의 분자간 극성력과 수소결합에 의한 상호인력으로 용해된 용질-용매 기반의 용액인 것을 특징으로 한다.In the present invention, the spray solution is characterized in that it is a solute-solvent based solution dissolved by mutual attraction due to polar forces and hydrogen bonds between molecules of the alcohol and the aqueous solvent.
상기의 다른 기술적 과제를 해결하기 위하여 본 발명은, 상기 방법으로 제조되되, 코어로 배치되는 소수성 입자; 및 상기 소수성 입자의 외부에 코팅되어 쉘로 배치되는 친수성 그래핀;을 포함하여 형성되는 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체를 제공한다.In order to solve the above other technical problems, the present invention, doedoe produced by the above method, the hydrophobic particles arranged as a core; And hydrophilic graphene coated on the outside of the hydrophobic particles and arranged as a shell; characterized in that it is formed, including, provides a core-shell composite using a kneading method.
본 발명에 있어서, 상기 소수성 입자는, 천연흑연, 인조흑연, 탄소나노튜브, 카본블랙, 탄소 코팅된 금속, 탄소 코팅된 금속산화물, 그래핀, 소프트 카본 및 하드 카본으로 이루어진 군에서 선택되는 1종 이상인 것을 특징으로 한다.In the present invention, the hydrophobic particles are one selected from the group consisting of natural graphite, artificial graphite, carbon nanotubes, carbon black, carbon-coated metals, carbon-coated metal oxides, graphene, soft carbon, and hard carbon. It is characterized by more than
본 발명에 있어서, 상기 친수성 그래핀은, 산화그래핀 또는 산화그래핀환원물인 것을 특징으로 한다.In the present invention, the hydrophilic graphene is characterized in that it is graphene oxide or a reduced graphene oxide.
상기 과제의 해결 수단에 의한 본 발명에 따르면, 소수성 표면을 갖는 입자와 알코올을 혼합하는 반죽법을 이용하여 활물질 반죽을 제조함으로써, 알코올에 의해 소수성 입자의 표면을 젖게 만들어 산화그래핀 또는 산화그래핀환원물과 분산된 후 분무 건조를 통하여 소수성 입자가 코어로 배치되고 산화그래핀 또는 산화그래핀환원물이 쉘로 배치된 코어-쉘 구조의 복합체 분말을 보다 간단한 공정으로 대량 생산할 수 있는 효과가 있다.According to the present invention by means of solving the above problems, by preparing an active material dough using a kneading method of mixing particles having a hydrophobic surface with alcohol, the surface of the hydrophobic particles is wetted with alcohol to graphene oxide or graphene oxide There is an effect of mass-producing core-shell composite powder in which hydrophobic particles are arranged as a core and graphene oxide or graphene oxide reduced material is arranged as a shell through spray drying after being dispersed with a reducing material in a simpler process.
이에 따라 본 발명의 코어-쉘 복합체로 이루어진 고성능 복합 활물질은 전해질과의 계면에서 형성될 수 있는 부반응이 억제되고 전기전도성을 높일 수 있으므로, 고용량, 장수명 및 고안정성의 전기화학특성을 요구하는 이차전지용 전극에 적용되어 성능 향상을 도모할 수 있는 효과가 있다.Accordingly, the high-performance composite active material composed of the core-shell composite of the present invention can suppress side reactions that may be formed at the interface with the electrolyte and increase electrical conductivity, so that it can be used for secondary batteries requiring high capacity, long lifespan, and high stability electrochemical properties. It is applied to the electrode and has the effect of promoting performance improvement.
도 1은 본 발명에 따른 코어-쉘 복합체의 제조방법을 나타낸 순서도.
도 2는 실시예 1 및 비교예 1에서 흑연에 에탄올을 반죽한 여부에 따른 층 분리를 비교하여 나타낸 사진.
도 3a는 실시예 1에 따른 활물질-산화그래핀환원물 복합체 분말을 나타낸 SEM 사진이고, 도 3b는 도 3a를 확대하여 나타낸 SEM 사진.
도 4a는 흑연 및 산화그래핀환원물의 혼합 분말을 나타낸 SEM 사진이고, 도 4b는 도 4a를 확대하여 나타낸 SEM 사진.
도 5는 소수성 활물질인 순수 흑연을 나타낸 SEM 사진.
도 6a는 실시예 1에 따른 활물질-산화그래핀환원물 복합체 분말의 물 접촉각 사진이고, 도 6b는 흑연 및 산화그래핀환원물의 혼합 분말의 물 접촉각 사진이며, 도 6c는 순수 흑연의 물 접촉각 사진.
도 7a는 열중량 분석하여 나타낸 그래프이고, 도 7b는 도 7a에 대한 열중량 분석에 의해 얻어진 곡선의 미분 곡선을 나타낸 그래프이며, 도 7c는 도 7a의 A 영역을 확대하여 나타낸 그래프.1 is a flow chart showing a method for manufacturing a core-shell composite according to the present invention.
2 is a photograph showing a comparison of layer separation according to whether graphite is kneaded with ethanol in Example 1 and Comparative Example 1;
Figure 3a is a SEM picture showing the active material-oxidized graphene reducing material composite powder according to Example 1, Figure 3b is a SEM picture showing Figure 3a enlarged.
Figure 4a is a SEM picture showing a mixed powder of graphite and graphene oxide reducible material, Figure 4b is a SEM picture showing Figure 4a enlarged.
Figure 5 is a SEM picture showing pure graphite as a hydrophobic active material.
6A is a photograph of the water contact angle of the active material-reduced graphene oxide composite powder according to Example 1, FIG. 6B is a photograph of the water contact angle of the mixed powder of graphite and reduced graphene oxide, and FIG. 6C is a photograph of the water contact angle of pure graphite. .
7A is a graph shown by thermogravimetric analysis, FIG. 7B is a graph showing a differential curve of the curve obtained by thermogravimetric analysis for FIG. 7A, and FIG. 7C is a graph showing an enlarged area A of FIG. 7A.
이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.
본 발명은 반죽법을 이용한 소수성 입자 표면에 그래핀이 코팅된 코어-쉘 복합체의 제조방법에 관한 것으로, 코어-쉘 복합체를 제조하는 방법은 본 발명에 따른 코어-쉘 복합체의 제조방법을 순서도로 나타낸 도 1에 나타낸 바와 같이, 소수성 표면을 갖는 입자와 알코올을 혼합하여 활물질 반죽을 제조하는 단계(S10)와, 활물질 반죽과 친수성 그래핀을 혼합하여 분무 용액을 제조하는 단계(S20)와, 분무 용액을 분무 건조하여 소수성 입자의 표면에 그래핀이 코팅된 코어-쉘 복합체를 제조하는 단계(S30)를 포함하여 이루어진다.The present invention relates to a method for producing a core-shell composite in which graphene is coated on the surface of hydrophobic particles using a kneading method. As shown in FIG. 1, mixing the particles having a hydrophobic surface with alcohol to prepare an active material dough (S10), mixing the active material dough and hydrophilic graphene to prepare a spray solution (S20), and spraying and spray-drying the solution to prepare a core-shell composite coated with graphene on the surface of the hydrophobic particles (S30).
상술한 제조방법에 따르면 먼저, 소수성 표면을 갖는 입자와 알코올을 혼합하여 활물질 반죽을 제조한다(S10).According to the above-described manufacturing method, first, an active material dough is prepared by mixing particles having a hydrophobic surface with alcohol (S10).
설명에 앞서, 소수성 표면을 갖는 입자는 활물질의 코어가 되는 것으로, 그 표면이 소수성으로 이루어져 친수성을 갖는 물과 같은 수계 용매에 분산이 어려워 그래핀이 수계 분산된 용액 내에서 분산이 용이하지 않기 때문에 친수성 그래핀과 복합화가 이루어질 때 상 분리 현상이 발생한다.Prior to the description, the particles having a hydrophobic surface serve as the core of the active material, and since the surface is made hydrophobic and it is difficult to disperse in an aqueous solvent such as water having hydrophilicity, it is not easy to disperse in a solution in which graphene is dispersed in an aqueous solution. A phase separation phenomenon occurs when the composite is made with hydrophilic graphene.
이를 해결해 보고자, 본 단계에서는 소수성 표면을 갖는 입자가 친수성 용매 내 산화그래핀, 산화그래핀환원물 중 하나 이상의 그래핀과 균질 혼합이 될 수 있도록 알코올계 용매를 혼합하는 반죽법을 이용하여 활물질 반죽을 제조한다.In order to solve this problem, in this step, the active material is kneaded using a kneading method of mixing an alcohol-based solvent so that the particles having a hydrophobic surface can be homogeneously mixed with at least one graphene of graphene oxide and graphene oxide reducing material in a hydrophilic solvent to manufacture
알코올의 혼합으로 반죽법을 통하여 제조되는 활물질 반죽의 표면은 젖음(wetting)성을 갖게 되어 추후 산화그래핀이나 산화그래핀환원물과 균질하게 분산된 후 분무 건조될 때 소수성을 갖는 입자에 산화그래핀이나 산화그래핀환원물의 그래핀이 도포된 코어-쉘 구조의 복합체 형태의 파우더로 제조할 수 있게 된다.The surface of the active material dough prepared through the kneading method by mixing alcohol has a wetting property, and when it is spray-dried after being homogeneously dispersed with graphene oxide or graphene oxide reducing material, graphene oxide is added to particles having hydrophobicity. It can be manufactured as a powder in the form of a composite of core-shell structure coated with graphene of pin or graphene oxide reducing material.
소수성 입자는 탄소 코팅된 금속, 탄소 코팅된 금속산화물, 천연흑연, 인조흑연, 탄소나노튜브, 카본블랙, 소프트 카본, 하드 카본 및 그래핀으로 이루어진 군에서 1종 이상이 선택될 수 있으며, 이차전지용 활물질로 사용될 수 있는 소수성 표면을 갖는 입자를 의미한다.The hydrophobic particle may be at least one selected from the group consisting of carbon-coated metal, carbon-coated metal oxide, natural graphite, artificial graphite, carbon nanotube, carbon black, soft carbon, hard carbon, and graphene. It means a particle having a hydrophobic surface that can be used as an active material.
그중 흑연은 단위 구조가 탄소육각망평면이 평행하게 배열된 층상 구조로, 이들이 갖는 결정화도에 따라 천연흑연과 인조흑연으로 구분될 수 있는데, 흑연이 갖는 소수성은 물에 의해 흑연 표면의 불충분한 습윤성으로 불안정한 부산물 생성을 초래할 수 있는데, 이 경우 산화그래핀 또는 산화그래핀환원물이 코팅될 때 미분산된 흑연 입자가 응집되는 문제점이 있어, 소수성 입자를 코팅하는 것은 중요하다 할 수 있다.Among them, graphite has a layered structure in which carbon hexagonal planes are arranged in parallel, and can be classified into natural graphite and artificial graphite according to their crystallinity. It can lead to the production of unstable by-products. In this case, there is a problem in that undispersed graphite particles aggregate when graphene oxide or graphene oxide reducing material is coated, so it can be said that it is important to coat the hydrophobic particles.
반죽법에 사용되는 알코올은 메탄올, 에탄올, 프로판올, 이소프로필알코올, 부틸알코올 및 이소부틸알코올 중 어느 하나 이상의 알코올계 용매일 수 있으며, 상기 종류에 한정하는 것만은 아니고 소수성 활물질 입자와 반죽되어 소수성 활물질 입자의 표면에 젖음성을 부여할 수 있는 알코올계 용매라면 다양하게 사용할 수 있다.The alcohol used in the kneading method may be any one or more alcohol-based solvents selected from among methanol, ethanol, propanol, isopropyl alcohol, butyl alcohol, and isobutyl alcohol, and is not limited to the above types, and is kneaded with hydrophobic active material particles. Any alcohol-based solvent capable of imparting wettability to the surface of the particles can be used in various ways.
소수성 입자와 알코올은 1 : 1 내지 5의 중량비율로 혼합될 수 있다. 알코올이 소수성 입자 1 중량비율 대비하여 1 중량비율 미만으로 반죽되면 소수성 입자의 표면에 젖음성을 충분히 제공하지 못하여 친수성 그래핀의 균일한 코팅이 어려워져 결국 안정적인 형태의 코어-쉘 복합체를 제조하지 못하는 단점이 있다. 반면 알코올이 5 중량비율을 초과하여 혼합되면 오히려 소수성 입자의 형태 유지가 쉽지 않아 이 역시 코어-쉘 복합체로 용이하게 형성되지 않게 되는 문제점이 있다.Hydrophobic particles and alcohol may be mixed in a weight ratio of 1:1 to 5. If the alcohol is kneaded at less than 1 weight ratio relative to 1 weight ratio of the hydrophobic particles, wettability cannot be sufficiently provided to the surface of the hydrophobic particles, making it difficult to uniformly coat the hydrophilic graphene. there is On the other hand, when the alcohol is mixed in an amount exceeding 5% by weight, it is not easy to maintain the shape of the hydrophobic particles, and this also has a problem in that it is not easily formed into a core-shell composite.
소수성 입자와 알코올을 반죽함에 있어 5 내지 20분 동안 실시할 수 있다. 5분 미만으로 반죽하면 소수성 입자를 분산시켜 그 표면에 젖음성을 제공하기엔 부족한 시간이며, 20분을 초과하면 그 이하의 시간으로 반죽한 경우와 비교하여 더 탁월한 반죽 효율이 나타나지 않아 굳이 20분을 초과하여 반죽할 필요성은 없다.Kneading the hydrophobic particles and alcohol may be performed for 5 to 20 minutes. If kneaded for less than 5 minutes, it is insufficient time to disperse hydrophobic particles and provide wettability to the surface, and if it exceeds 20 minutes, the kneading efficiency is not superior compared to the case of kneading for less than 20 minutes. There is no need to knead it.
다음으로, 활물질 반죽과 친수성 그래핀을 혼합하여 분무 용액을 제조한다(S20).Next, a spray solution is prepared by mixing the active material dough and hydrophilic graphene (S20).
친수성 그래핀은, 물(water, H2O)을 포함하는 수계 용매에 산화그래핀 또는 산화그래핀환원물이 분산되어 형성되는 그래핀 용액으로, 수분산된 산화그래핀이나 산화그래핀환원물이 소수성 표면을 갖는 입자의 표면에 균일하게 도포되어 활물질 성능을 향상시킬 수 있게 된다.Hydrophilic graphene is a graphene solution formed by dispersing graphene oxide or reduced graphene oxide in an aqueous solvent containing water (H 2 O). It is uniformly applied to the surface of the particle having the hydrophobic surface to improve the performance of the active material.
즉 그래핀 용액은 그래파이트를 산화시킨 후 분산 및 박리하여 형성되는 산화그래핀을 양이온-파이 상호작용을 통해 형성되는 산화그래핀 분산 용액이거나, 이러한 산화그래핀 분산 용액에 환원제를 투입하여 환원시킨 산화그래핀환원물 분산 용액으로 이루어질 수 있다. 그래핀 용액으로 산화그래핀 분산 용액이 사용되는 경우, 추후 분무 용액을 분무 건조 하기 전이나 분무 건조하여 코어-쉘 복합체를 형성한 후 열처리 등의 과정을 거쳐 산화그래핀을 환원시켜 결국 활물질-산화그래핀환원물의 코어-쉘 복합체를 제조할 수 있게 된다.That is, the graphene solution is a graphene oxide dispersion solution formed by cation-pi interaction of graphene oxide formed by oxidizing graphite and then dispersing and exfoliating it, or a graphene oxide dispersion solution formed by adding a reducing agent to the graphene oxide dispersion solution to reduce oxidation. It may consist of a graphene reducing material dispersion solution. When a graphene oxide dispersion solution is used as the graphene solution, the graphene oxide is reduced through a process such as heat treatment after forming a core-shell composite by spray drying or before spray drying the spray solution, and eventually active material-oxidation. It is possible to prepare a core-shell composite of graphene reduced material.
산화그래핀, 산화그래핀환원물 중 하나 이상의 그래핀이 수계 물에 분산된 용액에 있어서, 그래핀이 분산되어 있던 물과 소수성 입자를 반죽한 알코올과 같은 극성-극성의 경우 용해도 파라미터(solubility parameter, δ)를 이용하여 극성력과 수소결합에 의한 분자 간 상호인력으로 용질-용매 간 용해도 방식을 도입함으로써, 소수성의 활물질과 수분산된 그래핀의 분산도를 향상시킬 수 있다.In a solution in which one or more of graphene oxide and graphene oxide reducer is dispersed in aqueous water, solubility parameter , δ), it is possible to improve the dispersion of the hydrophobic active material and the water-dispersed graphene by introducing a solubility method between the solute and the solvent by mutual attraction between molecules due to polar forces and hydrogen bonds.
용해도 파라미터는 특별히 제한되지 않고, 공지된 방식에 따를 수 있다. 예를 들면, HSP(Hansen solubility parameter)에 따라 분자 간 분산력, 분자 간 극성력, 분자 간 수소결합 성분에 의해 계산되거나 구해질 수 있다. 즉 용해도 파라미터는 소수성 입자와 반죽된 알코올과, 그래핀이 분산되어져 있던 물의 상호 관계로부터 분무 용액의 거동과 물 및 알코올의 적합성을 예측할 수 있으며, 용해도가 용매의 응집성과 밀접한 관계가 있다고 가정하여, 응집 에너지 밀도만으로 용해도 파라미터를 표현한 것이다.The solubility parameter is not particularly limited and may follow a known method. For example, it can be calculated or obtained by intermolecular dispersion forces, intermolecular polar forces, and intermolecular hydrogen bond components according to HSP (Hansen solubility parameter). That is, the solubility parameter can predict the behavior of the spray solution and the suitability of water and alcohol from the mutual relationship between the alcohol kneaded with the hydrophobic particles and the water in which the graphene is dispersed, and assuming that the solubility is closely related to the cohesiveness of the solvent, The solubility parameter is expressed only with the cohesive energy density.
마지막으로, 분무 용액을 분무 건조하여 소수성 입자의 표면에 그래핀이 코팅된 코어-쉘 복합체를 제조한다(S30).Finally, the spray solution is spray-dried to prepare a core-shell composite coated with graphene on the surface of the hydrophobic particles (S30).
소수성 표면을 갖는 입자와, 산화그래핀 또는 산화그래핀환원물을 포함한 분무 용액을 분무 건조하여, 분무 건조되는 와중에 소수성 표면을 갖는 입자가 코어로 배치되고, 산화그래핀 및 산화그래핀환원물 중 하나 이상의 그래핀이 쉘로 배치된 코어-쉘 복합체 형태의 파우더를 형성할 수 있다.Particles having a hydrophobic surface and a spray solution containing graphene oxide or reduced graphene oxide are spray-dried, and during the spray drying, the particles having a hydrophobic surface are placed as cores, and among the graphene oxide and reduced graphene oxide It can form a powder in the form of a core-shell composite in which one or more graphenes are arranged as a shell.
합성된 코어-쉘 복합체 분말에 있어서, 소수성 입자의 표면에 대한 산화그래핀환원물의 평균 접촉각 범위는 10 내지 20°일 수 있으며, 10°미만의 접촉각이 되도록 제어할 필요성이 없으며, 20°를 초과하면 소수성 입자의 젖음성이 좋지 못함을 의미하기 때문에 소수성 입자 표면에 대한 산화그래핀환원물의 코팅막이 균일하게 형성되지 못하는 문제점이 있다.In the synthesized core-shell composite powder, the average contact angle range of the reduced graphene oxide with respect to the surface of the hydrophobic particles may be 10 to 20 °, there is no need to control the contact angle to be less than 10 °, and it exceeds 20 ° Since it means that the wettability of the hydrophobic particles is not good, there is a problem in that the coating film of the reduced graphene oxide on the surface of the hydrophobic particles is not uniformly formed.
이렇게 합성되는 분말 형태의 코어-쉘 복합체는 소수성 표면을 갖는 입자에 산화그래핀, 산화그래핀환원물 중 하나 이상의 그래핀이 도포되어 형성되는 고성능 복합 활물질로, 고성능 복합 활물질에 전기전도성을 부여하고, 표면 안정화를 이루면서 전해액과의 함침 특성을 향상시킬 수 있다. 이에 따라 고성능 복합 활물질과 전해질의 계면에 형성되는 부반응을 억제하고 전도성을 향상시켜 이차전지용 전극의 전기화학특성을 높일 수 있게 된다.The powdery core-shell composite thus synthesized is a high-performance composite active material formed by applying at least one graphene selected from graphene oxide and graphene oxide reducing material to particles having a hydrophobic surface, and imparts electrical conductivity to the high-performance composite active material. , it is possible to improve the impregnation characteristics with the electrolyte solution while achieving surface stabilization. Accordingly, it is possible to suppress side reactions formed at the interface between the high-performance composite active material and the electrolyte and improve the conductivity, thereby improving the electrochemical characteristics of the secondary battery electrode.
이하, 본 발명의 실시예를 더욱 상세하게 설명하면 다음과 같다. 단, 이하의 실시예는 본 발명의 이해를 돕기 위하여 예시하는 것일 뿐, 이에 의하여 본 발명의 범위가 한정되는 것은 아니다.Hereinafter, an embodiment of the present invention will be described in more detail. However, the following examples are merely illustrative to aid understanding of the present invention, and the scope of the present invention is not limited thereby.
<실시예 1><Example 1>
1-1. 흑연 반죽의 제조1-1. Preparation of Graphite Paste
소수성 활물질인 순수 흑연(순도 99.98%, POSCO 제조) 5g에 에탄올 10g을 첨가하고 스패츌러로 잘 혼합하였다. 이때, 소수성 표면 특성을 가진 흑연에 에탄올이 충분히 스며들도록 10분 동안 반죽하였다.10 g of ethanol was added to 5 g of pure graphite (purity 99.98%, manufactured by POSCO), which is a hydrophobic active material, and mixed well with a spatula. At this time, it was kneaded for 10 minutes so that ethanol was sufficiently permeated into the graphite having a hydrophobic surface property.
1-2. 산화그래핀 분산 용액의 제조1-2. Preparation of graphene oxide dispersion solution
순수 흑연(순도 99.9995%, -200메쉬, Alfar Aesar 제조) 10g, 발연질산 350㎖ 및 소듐 클로라이드 옥사이드(NaClO4) 74g을 실온에서 순차적으로 37g씩 나누어 혼합하였다. 혼합물을 48시간 동안 교반한 후 중화 과정과 세척, 여과 및 클리닝, 건조 과정을 거쳐 산화그래핀을 제조하였다. 상기의 과정을 통해 만들어진 산화그래핀은 300mg/ℓ 농도로 KOH가 녹아있는 증류수(pH 10)에 호모게나이저를 15,000 rpm으로 1시간 동안 처리하여 균일한 산화그래핀 분산 용액을 만들었다. 이후, 양이온-파이 상호작용을 인가시키기 위해서 상온에서 산화그래핀 분산 용액의 반응 시간을 1시간 이상 유지시킨 다음, 10시간 이상 동결 건조하여 분말 형태의 산화그래핀을 제조하였다. 분말 형태의 산화그래핀을 분산시키기 위한 용매로 증류수를 이용하여 300㎎/ℓ 농도의 산화그래핀 분산 용액을 제조하였다.10 g of pure graphite (purity 99.9995%, -200 mesh, manufactured by Alfar Aesar), 350 ml of fuming nitric acid, and 74 g of sodium chloride oxide (NaClO 4 ) were sequentially divided into 37 g each at room temperature and mixed. After stirring the mixture for 48 hours, graphene oxide was prepared through neutralization, washing, filtration, cleaning, and drying processes. The graphene oxide produced through the above process was treated with a homogenizer in distilled water (pH 10) in which KOH was dissolved at a concentration of 300 mg / ℓ for 1 hour at 15,000 rpm to make a uniform graphene oxide dispersion solution. Thereafter, in order to apply a cation-pi interaction, the reaction time of the graphene oxide dispersion solution was maintained at room temperature for 1 hour or more, and then freeze-dried for 10 hours or more to prepare graphene oxide in powder form. A graphene oxide dispersion solution having a concentration of 300 mg/L was prepared using distilled water as a solvent for dispersing graphene oxide in powder form.
1-3. 활물질-산화그래핀환원물 복합체 분말의 제조1-3. Preparation of Active Material-Graphene Oxide Reductant Composite Powder
실시예 1-1에서 제조한 흑연 반죽을 실시예 1-2에서 제조한 산화그래핀 분산 용액 50ml(0.5wt%)에 첨가하고 기계식 교반기로 1,000rpm으로 20분 동안 처리하여 흑연-산화그래핀 복합체 분무 용액을 제조한 후, 혼합 용액을 분무 건조하여 활물질-산화그래핀 복합 음극재 분말을 제조하였다. 분말을 17℃/min으로 가열하여 1,000℃에서 1시간 동안 열처리하여 활물질-산화그래핀환원물 분말을 제조하였다.The graphite paste prepared in Example 1-1 was added to 50 ml (0.5 wt%) of the graphene oxide dispersion solution prepared in Example 1-2, and treated with a mechanical stirrer at 1,000 rpm for 20 minutes to graphite-graphene oxide composite. After preparing the spray solution, the mixed solution was spray-dried to prepare an active material-graphene oxide composite negative electrode material powder. The powder was heated at 17°C/min and heat-treated at 1,000°C for 1 hour to prepare an active material-graphene oxide reduced powder.
<실시예 2><Example 2>
2-1. 흑연 반죽의 제조2-1. Preparation of Graphite Paste
소수성 활물질인 순수 흑연(순도 99.98%, POSCO 제조) 5g에 에탄올 10g을 첨가하고 스패츌러로 잘 혼합하였다. 이때, 소수성 표면 특성을 가진 흑연에 에탄올이 충분히 스며들도록 10분 동안 반죽하였다.10 g of ethanol was added to 5 g of pure graphite (purity 99.98%, manufactured by POSCO), which is a hydrophobic active material, and mixed well with a spatula. At this time, it was kneaded for 10 minutes so that ethanol was sufficiently permeated into the graphite having a hydrophobic surface property.
2-2. 산화그래핀환원물 분산 용액의 제조2-2. Preparation of graphene oxide reducible dispersion solution
순수 흑연(순도 99.9995%, -200메쉬, Alfar Aesar 제조) 10g, 발연질산 350㎖ 및 소듐 클로라이드 옥사이드(NaClO4) 74g을 실온에서 순차적으로 37g씩 나누어 혼합하였다. 혼합물을 48시간 동안 교반한 후 중화 과정과 세척, 여과 및 클리닝, 건조 과정을 거쳐 산화그래핀을 제조하였다. 상기의 과정을 통해 만들어진 산화그래핀은 300mg/ℓ 농도로 KOH가 녹아있는 증류수(pH 10)에 호모게나이저를 15,000 rpm으로 1시간 동안 처리하여 균일한 산화그래핀 분산 용액을 만들었다. 이후, 양이온-파이 상호작용을 인가시키기 위해서 상온에서 산화그래핀 분산 용액의 반응 시간을 1시간 이상 유지시킨 다음, 10시간 이상 동결 건조하여 분말 형태의 산화그래핀을 제조하였다. 분말 형태의 산화그래핀을 분산시키기 위한 용매로 증류수를 이용하였으며, 300㎎/ℓ 농도의 산화그래핀 분산 용액에 HI acid 170㎕를 넣고 16시간 동안 400rpm으로 교반하여 환원시킴으로써 고농도로 분산된 산화그래핀환원물 분산 용액을 제조하였다. 이때 산화그래핀환원물의 크기는 5 내지 10㎛였다.10 g of pure graphite (purity 99.9995%, -200 mesh, manufactured by Alfar Aesar), 350 ml of fuming nitric acid, and 74 g of sodium chloride oxide (NaClO 4 ) were sequentially divided into 37 g each at room temperature and mixed. After stirring the mixture for 48 hours, graphene oxide was prepared through neutralization, washing, filtration, cleaning, and drying processes. The graphene oxide produced through the above process was treated with a homogenizer in distilled water (pH 10) in which KOH was dissolved at a concentration of 300 mg / ℓ for 1 hour at 15,000 rpm to make a uniform graphene oxide dispersion solution. Thereafter, in order to apply a cation-pi interaction, the reaction time of the graphene oxide dispersion solution was maintained at room temperature for 1 hour or more, and then freeze-dried for 10 hours or more to prepare graphene oxide in powder form. Distilled water was used as a solvent for dispersing graphene oxide in powder form, and 170 μl of HI acid was added to a graphene oxide dispersion solution having a concentration of 300 mg/L and stirred at 400 rpm for 16 hours for reduction to obtain highly dispersed graphene oxide. A pinreducate dispersion solution was prepared. At this time, the size of the graphene oxide reduced material was 5 to 10 μm.
2-3. 활물질-산화그래핀환원물 복합체 분말의 제조2-3. Preparation of Active Material-Graphene Oxide Reductant Composite Powder
실시예 2-1에서 제조된 흑연 반죽을 실시예 2-2에서 제조된 산화그래핀환원물 분산 용액 50ml(0.5wt%)에 첨가하고 기계식 교반기로 1,000rpm으로 20분 동안 처리하여 흑연-산화그래핀환원물 복합체 분무 용액을 제조하였다. 혼합 용액을 분무건조하여 활물질-산화그래핀환원물 복합체 분말을 제조하였다.The graphite paste prepared in Example 2-1 was added to 50 ml (0.5 wt%) of the graphene oxide reducing material dispersion solution prepared in Example 2-2 and treated with a mechanical stirrer at 1,000 rpm for 20 minutes to graphite-graphite oxide. A spray solution of the fin-reductant complex was prepared. The mixed solution was spray-dried to prepare an active material-oxidized graphene reducing material composite powder.
<비교예 1><Comparative Example 1>
비교예 1에서는 실시예 1 및 2에서와 같이 흑연에 에탄올을 첨가 및 반죽하여 흑연 반죽으로 제조하지 않았다. 즉 소수성 활물질인 순수 흑연(순도 99.98%, POSCO 제조) 5g을 산화그래핀 분산 용액 50ml(0.5wt%)에 첨가하고 기계식 교반기로 1,000rpm으로 20분 동안 처리하여 흑연-산화그래핀환원물 복합체 분무 용액을 만들었다. 혼합 용액을 분무 건조하여 활물질-산화그래핀환원물 복합체 분말을 제조하였다.In Comparative Example 1, as in Examples 1 and 2, graphite was not prepared by adding and kneading ethanol to graphite. That is, 5 g of pure graphite (purity 99.98%, manufactured by POSCO), a hydrophobic active material, was added to 50 ml (0.5 wt%) of a graphene oxide dispersion solution, and treated with a mechanical stirrer at 1,000 rpm for 20 minutes to spray the graphite-graphene oxide reduced complex. made a solution The mixed solution was spray-dried to prepare an active material-oxidized graphene reducing material composite powder.
<시험예 1><Test Example 1>
본 시험예에서는 실시예 1에서 제조된 활물질-산화그래핀환원물 복합체 분말과, 흑연 분말과 실시예 2에서 제조된 산화그래핀환원물 분산 용액을 분무 건조한 산화그래핀환원물 분말을 혼합한 혼합 분말과, 순수 흑연의 형태를 분석해 보았다.In this test example, a mixture of the active material-reduced oxide powder prepared in Example 1, the graphite powder and the reduced graphene oxide dispersed solution prepared in Example 2, and the powder of the reduced graphene oxide spray-dried The powder and the form of pure graphite were analyzed.
관련하여, 우선 도 2는 실시예 1 및 비교예 1에서 흑연에 에탄올을 반죽한 여부에 따른 층 분리를 비교하여 사진으로 나타낸 것이다. 도 2에 나타난 바와 같이 실시예 1에서는 흑연에 에탄올을 혼합하는 반죽법을 통하여 흑연 표면에 젖음성이 제공되어 층 분리가 생성되지 않아 균일 혼합이 이루어짐을 확인할 수 있었던 반면, 비교예 1의 경우 순수 흑연 자체에 에탄올을 이용한 반죽을 하지 않아 흑연 표면에 젖음성이 제공되지 못했기 때문에 층 분리가 생성됨을 확인할 수 있었다. 비교예 1에서와 같이 층 분리가 생기면 순수 흑연과 산화그래핀환원물의 균질 혼합이 되지 않음을 알 수 있다.In this regard, FIG. 2 is a photographic comparison of layer separation depending on whether graphite is kneaded with ethanol in Example 1 and Comparative Example 1. As shown in FIG. 2, in Example 1, wettability was provided to the graphite surface through the kneading method of mixing ethanol with graphite, so that layer separation was not generated and uniform mixing was achieved. On the other hand, in Comparative Example 1, pure graphite It was confirmed that layer separation was generated because wettability was not provided on the graphite surface because kneading using ethanol was not performed. As in Comparative Example 1, when layer separation occurs, it can be seen that homogeneous mixing of the pure graphite and the reduced graphene oxide is not possible.
도 3a는 실시예 1에 따른 활물질-산화그래핀환원물 복합체 분말을 10.0kV에서 측정하여 5천 배율로 확대하여 SEM 사진으로 나타낸 것이고, 도 3b는 도 3a를 확대하여 나타내되, 10.0kV에서 측정하여 만 배율로 확대하여 SEM 사진으로 나타낸 것이다. 도 3a 및 도 3b를 참조하면, 입자상의 흑연 표면에 산화그래핀환원물이 안정적으로 코팅되어 있음을 확인할 수 있다.Figure 3a is an SEM photograph of the active material-oxidized graphene-reduced composite powder according to Example 1 measured at 10.0 kV and enlarged to 5,000 magnification, Figure 3b is an enlarged view of Figure 3a, measured at 10.0 kV It was enlarged to 10,000 magnification and shown as a SEM image. Referring to Figures 3a and 3b, it can be seen that the graphene oxide is stably coated on the surface of the particulate graphite.
도 3과의 비교를 위하여, 흑연 분말과 실시예 2에서 제조된 산화그래핀환원물 분산 용액을 분무 건조한 산화그래핀환원물 분말을 혼합한 혼합 분말의 형태를 확인해 보았다(흑연 분말 및 산화그래핀환원물 분말의 중량은 실시예 1에서와 대등하게 하였다.). 관련하여, 도 4a는 흑연 및 산화그래핀환원물의 혼합 분말을 10.0kV에서 측정하여 5천 배율로 확대하여 나타낸 SEM 사진이고, 도 4b는 도 4a를 확대한 것으로 10.0kV에서 측정하여 만 배율로 확대하여 SEM 사진으로 나타낸 것이다. 도 4a 및 도 4b를 참조하면 흑연 분말의 표면에 코팅되지 못한 산화그래핀환원물이 흑연 분말과 분리된 상태로 존재함이 확인되며, 도 4b에서 흑연 분말(G)의 표면에 산화그래핀환원물(rGO)이 균일한 피막으로 코팅되지 못하고 뭉쳐진 상태로 흑연 분말(G)의 표면에 붙어있는 현상이 확인되었다. 또한 도 5는 소수성 활물질인 순수 흑연을 10.0kV에서 측정하여 만 배율로 확대하여 SEM 사진으로 나타낸 것으로, 도 5를 참조하면, 외부에 코팅되지 않은 순수 흑연 형태가 확인된다. 이처럼 도 4 및 도 5에서와는 달리 실시예 1의 활물질-산화그래핀환원물 복합체 분말을 나타낸 도 3을 참조하면, 소수성 입자의 표면에 젖음성이 제공되어 산화그래핀환원물의 코팅이 안정적으로 이루어진 복합체가 형성됨을 확인할 수 있다.For comparison with FIG. 3, the form of the mixed powder obtained by mixing the graphite powder and the graphene oxide reducing material dispersion solution prepared in Example 2 by spray drying was confirmed (graphite powder and graphene oxide powder). The weight of the reduced product powder was equal to that in Example 1). In relation to this, FIG. 4a is an SEM image showing a mixture of graphite and graphene oxide reduced powder measured at 10.0 kV and magnified by 5,000 magnifications, and FIG. 4b is an enlarged image of FIG. 4a measured at 10.0 kV and magnified by 10 thousand magnifications It is shown as a SEM picture. Referring to FIGS. 4A and 4B , it is confirmed that the reduced graphene oxide that is not coated on the surface of the graphite powder exists in a state separated from the graphite powder. It was confirmed that the water (rGO) was not coated with a uniform film and adhered to the surface of the graphite powder (G) in an agglomerated state. In addition, Figure 5 is a hydrophobic active material, pure graphite measured at 10.0 kV and enlarged at a magnification of 10,000 to show an SEM photograph. Referring to Figure 5, the form of pure graphite not coated on the outside is confirmed. Unlike FIGS. 4 and 5, referring to FIG. 3 showing the powder of the active material-reduced graphene oxide composite of Example 1, wettability is provided to the surface of the hydrophobic particles so that the composite is stably coated with the reduced graphene oxide. formation can be confirmed.
<시험예 2><Test Example 2>
본 시험예에서는 실시예 1에서 제조된 활물질-산화그래핀환원물 복합체 분말과, 흑연 분말과 실시예 2에서 제조된 산화그래핀환원물 분산 용액을 분무 건조한 산화그래핀환원물 분말을 혼합한 혼합 분말과, 순수 흑연의 물 접촉각(contact angle)을 비교하여 분석해 보았다.In this test example, a mixture of the active material-reduced oxide powder prepared in Example 1, the graphite powder and the reduced graphene oxide dispersed solution prepared in Example 2, and the powder of the reduced graphene oxide spray-dried The powder and the water contact angle of pure graphite were compared and analyzed.
관련하여, 보통 접촉각은 액체-기체 경계면과 액체-고체 경계면의 사잇각을 액체 내부 쪽에서 잰 각도로, 표면 코팅이 잘 되었는지를 확인할 수 있는 것으로, 액체의 고체 표면에 대한 평균 접촉각은 표면 코팅 정도로 예측할 수 있게 된다.In this regard, the normal contact angle is the angle between the liquid-gas interface and the liquid-solid interface measured from the inside of the liquid, which can confirm whether the surface coating is good. there will be
접촉각은 접촉각 측정기(Phoenix 300, Surface & Electro-Optics Co.)를 이용하여 측정하였으며, 이를 위해 넓이 2×2cm, 깊이 2mm의 홈이 파진 유리 기판에 분말 상태의 시료를 올리고 유리 기판의 높이에 맞춰 평평하게 채운 후, 접촉각 측정기에 놓고 주사기를 통해 물을 한 방울 떨어뜨린 후 측정하였다.The contact angle was measured using a contact angle measuring instrument (Phoenix 300, Surface & Electro-Optics Co.). After filling it flat, it was placed in a contact angle measuring instrument and measured after dropping a drop of water through a syringe.
도 6a는 실시예 1에 따른 활물질-산화그래핀환원물 복합체 분말의 물 접촉각 사진을 나타낸 것이고, 도 6b는 흑연 및 산화그래핀환원물의 혼합 분말의 물 접촉각 사진을 나타낸 것이며, 도 6c는 순수 흑연의 물 접촉각 사진을 나타낸 것이다.Figure 6a shows a water contact angle photograph of the active material-graphene oxide reduced composite powder according to Example 1, Figure 6b shows a water contact angle photograph of the mixed powder of graphite and graphene oxide reduced, Figure 6c is pure graphite It shows the water contact angle picture of
산화그래핀환원물이 소수성 입자 표면에 균일하게 코팅되기 위해서는 소수성 입자 표면에 대한 분무 용액의 평균 접촉각을 낮추는 것이 중요하며, 도 6a를 참조하면 소수성 활물질 입자 표면과, 이러한 표면에 접촉되는 분무 용액 간에 형성되는 접촉각이 낮아짐을 확인할 수 있었다. 소수성의 활물질 입자와 반죽되는 알코올은 극성이고, 친수성 그래핀을 구성하는 수계 용매 역시 극성으로, 극성 분자-극성 분자 간의 극성과 수소결합에 의해 알코올과 물이 상호 인력으로 용해도가 높아져 소수성 입자 표면에 대한 분무 용액의 평균 접촉각이 낮아짐으로써 소수성 활물질 입자 표면에 친수성 그래핀 코팅막을 얇고 균일하게 형성된 것이다.In order for the graphene oxide reducing material to be uniformly coated on the surface of the hydrophobic particles, it is important to lower the average contact angle of the spray solution on the surface of the hydrophobic particles. Referring to FIG. It was confirmed that the formed contact angle was lowered. The alcohol kneaded with the hydrophobic active material particles is polar, and the water-based solvent constituting the hydrophilic graphene is also polar, and the solubility of alcohol and water increases due to mutual attraction due to the polarity and hydrogen bonding between polar molecules and polar molecules, forming the surface of the hydrophobic particles. A thin and uniform hydrophilic graphene coating film is formed on the surface of the hydrophobic active material particle by lowering the average contact angle of the spray solution.
도 6b(접촉각: 102.28°) 및 도 6c(접촉각: 120.64°)와 달리 도 6a에서와 같이 유리 기판의 표면에 대한 실시예 1의 활물질-산화그래핀환원물 복합체 분말의 접촉각은 13.83°인 바, 평균 접촉각 범위가 10 내지 20°임이 확인될 수 있으며, 상기 범위에서 산화그래핀환원물이 소수성 입자에 코팅이 균일하게 이루어짐에 따라 활물질과 전해질의 접촉 면적을 극대화할 수 있음을 알 수 있다.Unlike FIG. 6b (contact angle: 102.28°) and FIG. 6c (contact angle: 120.64°), as shown in FIG. 6a, the contact angle of the active material-graphene oxide composite powder of Example 1 on the surface of the glass substrate is 13.83°. , It can be confirmed that the average contact angle range is 10 to 20 °, and it can be seen that the contact area between the active material and the electrolyte can be maximized as the graphene oxide reducing material is uniformly coated on the hydrophobic particles in the above range.
<시험예 3><Test Example 3>
본 시험예에서는 실시예 1에서 제조된 활물질-산화그래핀환원물 복합체 분말(G@rGO)과, 흑연 분말과 실시예 2에서 제조된 산화그래핀환원물 분산 용액을 분무 건조한 산화그래핀환원물 분말을 단순히 혼합한 혼합 분말(G/rGO)과, 순수 흑연(G)의 열중량 분석(TGA)을 해 보았다. 단, G/rGO의 경우 정확한 열중량 분석 결과를 얻기 위하여 실시예 1의 활물질 및 산화그래핀환원물의 중량과 동일하게 맞추었다.In this test example, the active material-reduced graphene oxide composite powder (G@rGO) prepared in Example 1, the graphite powder and the graphene reduced oxide dispersion solution prepared in Example 2 were spray-dried and the graphene reduced oxide Thermogravimetric analysis (TGA) of pure graphite (G) and mixed powder (G/rGO) in which the powders were simply mixed were performed. However, in the case of G/rGO, the weights of the active material and the graphene oxide reducing material of Example 1 were set equal to each other in order to obtain an accurate thermogravimetric analysis result.
관련하여, 열중량 분석은 열중량 분석기(TA Instruments, TGA Q50)를 이용하여 측정하였으며, 이를 위해 각 시료를 건조된 분말 상태로 준비하고, 세라믹팬에 10mg 정도 담고 상온에서 100℃까지 가열하여 시료 내의 수분을 제거한 후 40℃로 냉각하여 40℃에서부터 900℃까지 10℃/min으로 무게 변화를 측정하였다.In relation to this, thermogravimetric analysis was measured using a thermogravimetric analyzer (TA Instruments, TGA Q50). For this purpose, each sample was prepared in a dried powder state, about 10 mg was put in a ceramic pan and heated from room temperature to 100 ° C. After removing the water inside, it was cooled to 40 ° C and the weight change was measured at 10 ° C / min from 40 ° C to 900 ° C.
열중량 분석한 결과를 도 7a에 그래프로 나타내었고, 도 7b는 도 7a에 대한 열중량 분석에 의해 얻어진 곡선의 미분 곡선을 그래프로 나타낸 것이며, 도 7c는 도 7a의 A 영역을 확대하여 나타낸 것이다.The result of thermogravimetric analysis is shown in a graph in FIG. 7a, FIG. 7b is a graph showing the differential curve of the curve obtained by thermogravimetric analysis for FIG. 7a, and FIG. 7c is an enlarged view of area A in FIG. 7a. .
도 7b는 도 7a를 미분한 그래프로, 도 7a의 열중량 분석에 의해 얻어진 열중량 곡선의 미분 곡선(derivative thermogravimetric curve)을 나타낸 그래프인데, 이러한 미분 곡선은 열중량 분석에 의해 측정된 데이터로부터 변환되어 얻어질 수 있으며, X축 값은 온도(℃)이고, y축 값은 온도에 따른 중량의 감소 속도(%/℃)를 의미한다. 도 7b에 의하면, 중량 손실이 발생하기 시작하는 온도에서 피크가 발생하고, 온도에 따른 중량 손실률이 최대인 지점에서 최대값을 나타내기 때문에 온도에 따른 중량 손실률의 변화를 용이하게 파악할 수 있다.FIG. 7B is a graph that is the derivative of FIG. 7A and shows a derivative curve of the thermogravimetric curve obtained by the thermogravimetric analysis of FIG. 7A, which is converted from the data measured by the thermogravimetric analysis. It can be obtained, the X-axis value is the temperature (℃), and the y-axis value means the weight reduction rate (% / ℃) according to the temperature. According to FIG. 7B, since a peak occurs at the temperature at which weight loss starts to occur and the maximum value is displayed at the point where the weight loss rate with temperature is maximum, the change in weight loss rate with temperature can be easily grasped.
도 7a의 A 부분을 확대한 도 7c를 참조하면, 산화그래핀환원물의 존재 여부에 따라 곡선상 단차 여부를 확인할 수 있는 바, 순수 흑연(G)의 경우 700℃ 부근에서 곡선상 단차 없이 중량 감소가 일어나고, 본 발명의 실시예 1에 따른 활물질-산화그래핀환원물 복합체 분말(G@rGO)의 경우, 산화그래핀환원물이 활물질의 표면에 코팅되어 있어 흑연(G) 자체 보다 상대적으로 낮은 온도에서 열분해가 일어난다.Referring to FIG. 7c in which part A of FIG. 7a is enlarged, whether or not there is a step on the curve according to the presence or absence of a graphene oxide reducing material, in the case of pure graphite (G), the weight decreases without a step on the curve around 700 ° C. occurs, and in the case of the active material-graphene oxide reducing material composite powder (G@rGO) according to Example 1 of the present invention, since the graphene oxide reducing material is coated on the surface of the active material, relatively lower than graphite (G) itself. Thermal decomposition occurs at the temperature
실시예 1(G@rGO)의 경우 활물질의 표면에 산화그래핀환원물의 결합이 잘 이루어졌기 때문에 분해온도 그래프 선의 단차가 나타나지 않아 열적 안정성을 가지는 반면, 흑연 분말과 산화그래핀환원물 분말을 단순히 혼합한 혼합 분말(G/rGO)의 경우 산화그래핀환원물과, 산화그래핀환원물에 포함되어 있던 oxide functional group과, 흑연 각각이 동시에 열분해되지 않고 시간차를 두고 별도로 열분해되기 때문에, 실시예 1과 달리 도 7c의 a 부분과 같은 단차가 더 생김을 확인할 수 있다.In the case of Example 1 (G@rGO), since the graphene oxide reducing material is well bonded to the surface of the active material, there is no step difference in the decomposition temperature graph line, so it has thermal stability, while graphite powder and graphene oxide reducing material powder are simply mixed. In the case of the mixed powder (G/rGO), the graphene oxide, the oxide functional group contained in the graphene oxide, and the graphite are not thermally decomposed at the same time, but separately thermally decomposed with a time difference. Unlike , it can be confirmed that more steps such as part a of FIG. 7c are formed.
이러한 열중량 분석 결과로부터, 흑연 분말과 산화그래핀환원물 분말을 단순히 혼합하여 흑연, 산화그래핀환원물 및 산화그래핀환원물이 갖고 있던 oxide functional group이 열분해되는 온도가 각각 상이하게 도출되는 혼합 분말(G/rGO)은 흑연의 표면에 산화그래핀환원물의 코팅이 되지 않음을 알 수 있고, 실시예 1에서 흑연 및 산화그래핀환원물의 단순 혼합 분말 보다 활물질의 표면에 산화그래핀환원물의 바인딩이 잘 이루어져 단일 형태의 복합체 형성이 잘 되어 열분해되는 것임을 알 수 있다.From these results of thermogravimetric analysis, a mixture in which graphite powder and graphene oxide reduced powder are simply mixed to obtain different thermal decomposition temperatures of graphite, graphene oxide, and graphene oxide reduced oxide functional groups. It can be seen that the powder (G/rGO) is not coated with the graphene oxide reducing material on the surface of graphite, and in Example 1, the graphene oxide reducing material is bound to the surface of the active material rather than the simple mixed powder of graphite and graphene oxide reducing material. It can be seen that this is well done and the formation of a single type complex is well done and thermal decomposition.
정리하면, 본 발명은 소수성 입자와 알코올을 혼합하는 반죽법을 통한 활물질 반죽과, 수계 용매 기반의 친수성 그래핀을 혼합한 분무 용액을 분무 건조함으로써 소수성 입자의 표면에 친수성 그래핀이 코팅된 코어-쉘 복합체를 수득할 수 있는 특징이 있다.In summary, the present invention is a core coated with hydrophilic graphene on the surface of hydrophobic particles by spray-drying an active material kneading method through a kneading method of mixing hydrophobic particles and alcohol and a spray solution in which hydrophilic graphene based on an aqueous solvent is mixed. There is a feature that can obtain a shell composite.
즉, 소수성의 활물질 입자의 표면에 알코올을 이용한 반죽법을 통해 산화그래핀 또는 산화그래핀환원물 분산 용액과 균질 분산이 이루어진 분무 용액을 얻은 후 분무 건조하여 소수성 활물질과 친수성 그래핀이 코어-쉘 구조로 형성된 고성능 복합 활물질을 전극에 적용함으로써, 필수적인 탄소 코팅의 문제점을 해결할 수 있는데 의미가 있다.That is, after obtaining a spray solution homogeneously dispersed with a graphene oxide or graphene oxide reduced dispersion solution through a kneading method using alcohol on the surface of the hydrophobic active material particles, the hydrophobic active material and the hydrophilic graphene are core-shell by spray drying. By applying a high-performance composite active material formed in the structure to the electrode, it is meaningful to solve the problem of the essential carbon coating.
따라서 본 발명의 코어-쉘 복합체로 이루어진 고성능 복합 활물질은 전해질과의 계면에서 형성될 수 있는 부반응을 억제할 수 있고, 이를 통하여 전기전도성을 높일 수 있으므로 고용량, 장수명 및 고안정성의 전기화학특성을 요구하는 이차전지용 전극에 적용되어 성능 향상을 도모할 수 있을 것으로 기대된다.Therefore, the high-performance composite active material composed of the core-shell composite of the present invention can suppress side reactions that may be formed at the interface with the electrolyte and, through this, increase electrical conductivity, requiring high capacity, long lifespan, and high stability electrochemical properties. It is expected that it can be applied to electrodes for secondary batteries to improve performance.
이상의 설명은 본 발명의 기술 사상을 예시적으로 설명한 것에 불과한 것으로, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자라면 본 발명의 본질적인 특성에서 벗어나지 않는 범위에서 다양한 수정 및 변형이 가능할 것이다. 따라서 본 발명에 개시된 실시예는 본 발명의 기술 사상을 한정하기 위한 것이 아니라, 설명하기 위한 것이고, 이러한 실시예에 의하여 본 발명의 기술 사상의 범위가 한정되는 것도 아니다. 본 발명의 보호 범위는 특허청구범위에 의하여 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술사상은 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다.The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are intended to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.
Claims (9)
상기 활물질 반죽과, 수계 용매 기반의 친수성 그래핀을 혼합하여 분무 용액을 제조하는 단계; 및
상기 분무 용액을 분무 건조하여 상기 소수성 입자의 표면에 상기 친수성 그래핀이 코팅된 코어-쉘 복합체를 제조하는 단계;를 포함하는 것을 특징으로 하는, 반죽법을 이용한 소수성 입자 표면에 그래핀이 코팅된 코어-쉘 복합체의 제조방법.preparing an active material paste by mixing hydrophobic particles and alcohol;
preparing a spray solution by mixing the active material dough with hydrophilic graphene based on an aqueous solvent; and
Preparing a core-shell composite in which the hydrophilic graphene is coated on the surface of the hydrophobic particle by spray-drying the spray solution; graphene is coated on the surface of the hydrophobic particle using the kneading method A method for producing a core-shell composite.
상기 소수성 입자는,
천연흑연, 인조흑연, 탄소나노튜브, 카본블랙, 탄소 코팅된 금속, 탄소 코팅된 금속산화물, 그래핀, 소프트 카본 및 하드 카본으로 이루어진 군에서 선택되는 1종 이상인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체의 제조방법.According to claim 1,
The hydrophobic particles,
Natural graphite, artificial graphite, carbon nanotube, carbon black, carbon-coated metal, carbon-coated metal oxide, graphene, soft carbon and hard carbon, characterized in that at least one selected from the group consisting of, using a kneading method A method for producing a core-shell composite.
상기 친수성 그래핀은,
물(H2O)을 포함하는 수계 용매에 산화그래핀 또는 산화그래핀환원물이 분산되어 형성되는 그래핀 용액인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체의 제조방법.According to claim 1,
The hydrophilic graphene,
A method for producing a core-shell composite using a kneading method, characterized in that it is a graphene solution formed by dispersing graphene oxide or graphene oxide reduced in an aqueous solvent containing water (H 2 O).
상기 그래핀 용액은,
그래파이트를 산화시킨 후 분산 및 박리하여 형성되는 산화그래핀을 양이온-파이 상호작용을 통해 형성되는 산화그래핀 분산 용액인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체의 제조방법.According to claim 3,
The graphene solution,
A method for producing a core-shell composite using a kneading method, characterized in that the graphene oxide dispersion solution formed by oxidizing graphite and then dispersing and exfoliating graphene oxide through a cation-pi interaction.
상기 그래핀 용액은,
그래파이트를 산화시킨 후 분산 및 박리하여 형성되는 산화그래핀을 양이온-파이 상호작용을 통해 산화그래핀 분산 용액을 형성하고, 상기 산화그래핀 분산 용액에 환원제를 투입하여 환원시킨 산화그래핀환원물 분산 용액인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체의 제조방법.According to claim 3,
The graphene solution,
After oxidizing graphite, graphene oxide formed by dispersing and exfoliating is formed through a cation-pi interaction to form a graphene oxide dispersion solution, and a reducing agent is added to the graphene oxide dispersion solution to disperse reduced graphene oxide. A method for producing a core-shell composite using a kneading method, characterized in that it is a solution.
상기 분무 용액은,
상기 알코올과 상기 수계 용매의 분자간 극성력과 수소결합에 의한 상호인력으로 용해된 용질-용매 기반의 용액인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체의 제조방법.According to claim 1,
The spray solution,
A method for producing a core-shell composite using a kneading method, characterized in that it is a solute-solvent based solution dissolved by the mutual attraction due to the polar force between the molecules of the alcohol and the aqueous solvent and the hydrogen bond.
코어로 배치되는 소수성 입자; 및
상기 소수성 입자의 외부에 코팅되어 쉘로 배치되는 친수성 그래핀;을 포함하여 형성되는 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체.It is prepared by the method of any one of claims 1 to 6,
hydrophobic particles disposed as cores; and
A core-shell composite using a kneading method, characterized in that it is formed including; hydrophilic graphene coated on the outside of the hydrophobic particle and disposed as a shell.
상기 소수성 입자는,
천연흑연, 인조흑연, 탄소나노튜브, 카본블랙, 탄소 코팅된 금속, 탄소 코팅된 금속산화물, 그래핀, 소프트 카본 및 하드 카본으로 이루어진 군에서 선택되는 1종 이상인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체.According to claim 7,
The hydrophobic particles,
Natural graphite, artificial graphite, carbon nanotube, carbon black, carbon-coated metal, carbon-coated metal oxide, graphene, soft carbon and hard carbon, characterized in that at least one selected from the group consisting of, using a kneading method core-shell complex.
상기 친수성 그래핀은,
산화그래핀 또는 산화그래핀환원물인 것을 특징으로 하는, 반죽법을 이용한 코어-쉘 복합체.According to claim 7,
The hydrophilic graphene,
A core-shell composite using a kneading method, characterized in that it is graphene oxide or graphene oxide reduced.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020210157220A KR102661213B1 (en) | 2021-11-16 | Method for preparing a core-shell structured composite coated with graphene on the surface of hydrophobic particles using a kneading method, and a core-shell structured composite prepared therefrom |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020210157220A KR102661213B1 (en) | 2021-11-16 | Method for preparing a core-shell structured composite coated with graphene on the surface of hydrophobic particles using a kneading method, and a core-shell structured composite prepared therefrom |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020240040682A Division KR20240042595A (en) | 2024-03-25 | Method for preparing a core-shell structured composite coated with graphene on the surface of hydrophobic particles using a kneading method, and a core-shell structured composite prepared therefrom |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20230071243A true KR20230071243A (en) | 2023-05-23 |
| KR102661213B1 KR102661213B1 (en) | 2024-04-25 |
Family
ID=
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101744122B1 (en) | 2016-12-12 | 2017-06-07 | 한국지질자원연구원 | Manufacturing method of crumpled graphene-carbon nanotube composite, crumpled graphene-carbon nanotube composite manufactured thereby and supercapacitor containing the composite |
| KR20210128176A (en) | 2020-04-16 | 2021-10-26 | 주식회사 그래핀올 | Method for Preparing Graphene-Carbon Nanotube Composite |
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101744122B1 (en) | 2016-12-12 | 2017-06-07 | 한국지질자원연구원 | Manufacturing method of crumpled graphene-carbon nanotube composite, crumpled graphene-carbon nanotube composite manufactured thereby and supercapacitor containing the composite |
| KR20210128176A (en) | 2020-04-16 | 2021-10-26 | 주식회사 그래핀올 | Method for Preparing Graphene-Carbon Nanotube Composite |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5777701B2 (en) | Method for producing two-dimensional sandwich nanomaterials based on graphene | |
| Wang et al. | One-step accurate synthesis of shell controllable CoFe 2 O 4 hollow microspheres as high-performance electrode materials in supercapacitor | |
| US9359675B2 (en) | Producing two-dimensional sandwich nanomaterials based on graphene | |
| JP5675989B2 (en) | Method for producing positive electrode material for lithium air secondary battery and lithium air secondary battery | |
| He et al. | Preparation and electrochemical performance of monodisperse Li 4 Ti 5 O 12 hollow spheres | |
| JP2007517760A (en) | Carbon nanotube paste and method of use | |
| KR101975033B1 (en) | Graphene having pores made by irregular and random, and Manufacturing method of the same | |
| Dang et al. | One-pot synthesis of manganese oxide/graphene composites via a plasma-enhanced electrochemical exfoliation process for supercapacitors | |
| Zhang et al. | Construction of a cathode using amorphous FePO4 nanoparticles for a high-power/energy-density lithium-ion battery with long-term stability | |
| Jiang et al. | An interlayer composed of a porous carbon sheet embedded with TiO 2 nanoparticles for stable and high rate lithium–sulfur batteries | |
| Zhu et al. | Performance improvement of N-doped carbon ORR catalyst via large through-hole structure | |
| Tang et al. | Hybrid porous bamboo-like CNTs embedding ultrasmall LiCrTiO 4 nanoparticles as high rate and long life anode materials for lithium ion batteries | |
| Wang et al. | 2D layered mesoporous MoO2/rGO composites for high performance anode materials in lithium-ion battery | |
| Chang-Jian et al. | Spray-drying synthesis of Li4Ti5O12 microspheres in pilot scale using TiO2 nanosheets as starting materials and their application in high-rate lithium ion battery | |
| Zhang et al. | Engineering of a bowl-like Si@ rGO architecture for an improved lithium ion battery via a synergistic effect | |
| Xu et al. | Fabricating SiO 2-coated V 2 O 5 nanoflake arrays for high-performance lithium-ion batteries with enhanced cycling capability | |
| Xing et al. | Three-dimensional printing of black phosphorous/polypyrrole electrode for energy storage using thermoresponsive ink | |
| Liu et al. | Novel red blood cell shaped α-Fe 2 O 3 microstructures and FeO (OH) nanorods as high capacity supercapacitors | |
| JP5186268B2 (en) | Novel co-crystalline metal compound and electrochemical redox active material using the same | |
| Wang et al. | Uniformly distributed 1T/2H-MoS2 nanosheets integrated by melamine foam-templated 3D graphene aerogels as efficient polysulfides trappers and catalysts in lithium-sulfur batteries | |
| Li et al. | NiCo2S4 nanosheets decorated on nitrogen-doped hollow carbon nanospheres as advanced electrodes for high-performance asymmetric supercapacitors | |
| KR102192291B1 (en) | A method of manufacturing an electrode for a super capacitor including crumpled graphene and an electrode for a supercapacitor prepared thereby | |
| Ali et al. | Synthesis and analysis of the impact of rGO on the structural and electrochemical performance of CoMnS for high-performance energy storage device | |
| Lu et al. | Integrating N-doped porous carbon-encapsulated ultrafine SnO2 with MXene nanosheets via electrostatic self-assembly as a superior anode material for lithium ion capacitors | |
| Hao et al. | Nanodesigns for Na3V2 (PO4) 3-based cathode in sodium-ion batteries: a topical review |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| E902 | Notification of reason for refusal | ||
| E601 | Decision to refuse application | ||
| A107 | Divisional application of patent |