CNT를 첨가한 Silicon/Carbon 음극소재의 전기화학적 특성

정민지 ( Min Zy Jung ),박지용 ( Ji Yong Park ),이종대 ( Jong Dae Lee ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.1

Silicon/Carbon/CNT, Anode material, Carbon nanotube, Magnesiothermic re실리콘의 부피팽창과 낮은 전기전도도를 개선하기 위하여 Silicon/Carbon/CNT 복합체를 제조하였다. Silicon/Carbon/CNT 합성물은 SBA-15를 합성한 후, 마그네슘 열 환원 반응으로 Silicon/MgO를 제조하여 Phenolic resin과 CNT를 첨가하여 탄화하는 과정을 통해 합성하였다. 제조된 Silicon/Carbon/CNT 합성물은 XRD, SEM, BET, EDS를 통해 특성을 분석하였다. 본 연구에서는 충방전, 사이클, 순환전압전류, 임피던스 테스트를 통해 CNT 첨가량에 따른 전기화학적 효과를 조사하였다. LiPF6 (EC:DMC:EMC=1 :1 :1 vol%) 전해액에서 Silicon/Carbon/CNT 음극활물질을 사용하여 제조한 코인셀은 CNT 함량이 7 wt% 일 때 1,718 mAh/g으로 높은 용량을 나타내었다. 코인셀의 사이클 성능은 CNT첨가량이 증가할수록 개선되었다. 11 wt%의 CNT를 첨가한 Silicon/Carbon/CNT 음극은 두 번째 사이클 이후 83%의 높은 용량 보존율을 나타냄을 알 수 있었다.duction, Lithium ion battery Silicon/Carbon/CNT composites as anode materials for lithium-ion batteries were synthesized to overcome the large volume change during lithium alloying-de alloying process and low electrical conductivity. Silicon/Carbon/CNT composites were prepared by the fabrication processes including the synthesis of SBA-15, magnesiothermic reduction of SBA-15 to obtain Si/MgO by ball milling, carbonization of phenolic resin with CNT and HCl etching. The prepared Silicon/ Carbon/CNT composites were analysed by XRD, SEM, BET and EDS. In this study, the electrochemical effect of CNT content to improve the capacity and cycle performance was investigated by charge/discharge, cycle, cyclic voltammetry and impedance tests. The coin cell using Silicon/Carbon/CNT composite (Si:CNT=93:7 in weight) in the electrolyte of LiPF6 dissolved in organic solvents (EC:DMC:EMC=1:1:1 vol%) has better capacity (1718 mAh/g) than those of other composition coin cells. The cycle performance of coin cell was improved as CNT content was increased. It is found that the coin cell (Si:CNT=89:11 in weight) has best capacity retension (83%) after 2nd cycle.

Carbon nanotubes: synthesis, properties and engineering applications

Nikita Gupta,Shipra Mital Gupta,S. K. Sharma 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp2 hybridization. CNT are considered to be rolled-up graphene with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.

Carbon nanotubes: synthesis, properties and engineering applications

Gupta Nikita,Gupta Shipra Mital,Sharma S. K. 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp2 hybridization. CNT are considered to be rolled-up graphene with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.

탄소나노튜브 표면 관능기가 탄소나노튜브/고분자 복합재료의 기계적 및 열적 특성에 미치는 영향

함은광(Eun-Kwang Ham),최웅기(Woong-Ki Choi),김영근(Young-Keun Kim),서민강(Min-Kang Seo) 한국고분자학회 2015 폴리머 Vol.39 No.6

본 연구에서는 탄소나노튜브 관능기의 형태가 탄소나노튜브/고분자 복합재료의 기계적 및 열적 특성에 미치는 영향에 관하여 알아보았다. 탄소나노튜브의 관능기를 정량적으로 분석하기위해 X-선 광전자 분광법을 사용하였다. 복합재료는 에폭시 수지와 비닐에스터 수지에 산처리된 탄소나노튜브를 0.7 wt%를 첨가하여 제작하였다. 실험결과, 탄소나노튜브/에폭시 복합재료는 8 M 질산으로 처리된 탄소나노튜브를 첨가하였을 때 가장 높은 기계적 특성을 나타내었으며, 탄소나노튜브/비닐에스터 복합재료는 황산/질산 혼합액으로 처리된 탄소나노튜브를 첨가하였을 때 기계적 특성이 향상됨을 알 수 있었다. 열전도도는 에폭시와 비닐에스터에 8 M 질산으로 처리된 탄소나노튜브가 첨가되었을 때 향상되었다. 이는 탄소나노튜브에 카보닐기(C=O)의 도입으로 탄소나노튜브/에폭시 복합재료의 계면접착력이 개선되었으며, 카복시기(O-C=O)의 증가는 탄소나노튜브/비닐에스터 복합재료의 기계적 물성 향상에 기여하였다. 또한 탄소나노튜브/에폭시 복합재료와 탄소나노튜브/비닐에스터 복합재료의 열전도도는 탄소나노튜브의 표면구조와 길이에 영향을 받는다고 판단된다. The influence of carbon nanotube (CNT) functional groups on mechanical and thermal properties of CNT/polymer composites was investigated. The functional groups of the CNT were quantitatively analyzed using X-ray photoelectron spectroscopy. The composites were prepared by adding the 0.7 wt% acid-treated CNT in the epoxy resins and vinyl ester resins, respectively. As a result, the CNT/epoxy composites showed the highest tensile and flexural properties when addition of the 8 M HNO3-treated CNT. Tensile and thermal properties of the CNT/vinyl ester composites were improved by addition of H2SO4/HNO3-treated CNT. Thermal conductivities of CNT/epoxy composites and CNT/vinyl ester composites were improved in 8M HNO3-treated CNT. Introduction of carbonyl group (C=O) on CNT led to improvement of interfacial bonding in CNT/epoxy composites. The increase in the content of carboxyl group (O-C=O) on CNT contributed to increase in mechanical properties of CNT/vinyl ester composites. Also, the thermal conductivity of CNT/epoxy composites and CNT/vinyl ester composites were probably influenced on the structure and length of the CNT.

Multi-walled Carbon Nanotube-Reinforced Hydroxyapatite Coating on Ti Substrates by Aerosol Deposition

한병동,박동수,류정호,최종진,윤운하,이병국,김현이 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.10

Multi-walled carbon nanotube (CNT) reinforced hydroxyapatite composite coating with a thickness of 5 μm has been successfully deposited on Ti substrate using aerosol deposition (AD). The coating had a dense microstructure with no cracks or pores, showing good adhesion with the Ti substrate. Microstructural observation using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed that CNTs with original tubular morphology were found in the hydroxyapatite-CNT (HA-CNT) composite coating. Measurements of hardness and elastic modulus for the coating were performed by nanoindentation tests, indicating that the mechanical properties of the coating were remarkably improved by the addition of CNT to HA coating. Therefore, HA-CNT composite coating produced by AD is expected to be potentially applied to the coating for high load bearing implants. Multi-walled carbon nanotube (CNT) reinforced hydroxyapatite composite coating with a thickness of 5 μm has been successfully deposited on Ti substrate using aerosol deposition (AD). The coating had a dense microstructure with no cracks or pores, showing good adhesion with the Ti substrate. Microstructural observation using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed that CNTs with original tubular morphology were found in the hydroxyapatite-CNT (HA-CNT) composite coating. Measurements of hardness and elastic modulus for the coating were performed by nanoindentation tests, indicating that the mechanical properties of the coating were remarkably improved by the addition of CNT to HA coating. Therefore, HA-CNT composite coating produced by AD is expected to be potentially applied to the coating for high load bearing implants.

탄소나노튜브 페이스트 접합에 의한 탄소계 복합저항체의 전기적 특성

이선우,김은민 한국전기전자재료학회 2023 전기전자재료학회논문지 Vol.36 No.5

A carbon-based hybrid resistor was fabricated using carbon nanotube (CNT) paste as an adhesive layer to establish electrically continuous ohmic contacts between CNT sheets and different CNT sheet or copper based metal alloy plates, and its electrical properties were evaluated. CNT sheets were fabricated using vacuum filtration with a CNT solution dispersed in isopropyl alcohol (IPA) solvent. The electrical characteristics of these carbon-based hybrid resistors were investigated. The CNT paste fulfilled the requirements for forming ohmic contacts between CNT sheets and metal alloy plates, which was attributed to the lowest work function difference and excellent wettability at the interface.

실내실험 및 수치해석을 통한 Carbon Nanotube의 콘크리트슬래브 열전달 효과 검증

김희수,반호기 한국지반환경공학회 2019 한국지반환경공학회논문집 Vol.20 No.1

본 연구에서는 염화물, 전열선 등을 이용한 기존 결빙방지기술의 문제점인 도로 및 주변 구조물 내구성 저하, 많은 인력과 유지비용이 필요로 하는 등을 해소하고자 Carbon nanotube(CNT)를 이용한 결빙방지기술에 대한 기초자료로 실내실험과 수치해석 방법을 제시하였다. 이를 위해 실내실험과 수치해석을 통한 검증을 수행하였다. 실내실험은 CNT를 콘크리트 실험체 중심에 1개 삽입 후 냉동 Chamber를 이용하여 주변온도 및 실험체의 내부온도를 -10°C로 유지하였으며, CNT를 60°C로 발열시켰다. 콘크리트 표면 온도를 측정하여 발열체로부터 0°C까지의 거리인 유효발열거리를 확인하였다. 또한 열 중첩에 의한 CNT 간의 간격을 결정하기 위해 CNT를 150, 200, 300mm의 간격으로 삽입하여 총 4가지의 Case로 실내실험을 진행하였다. 실내실험과 함께 콘크리트 실험체의 열전도도 분석을 위한 수치해석을 수행하였다. This paper presents a method to deice concrete pavement with carbon nanotube(CNT) as an heating material so as to avoid the adverse effects of conventional deicing method such as salt on the structure, function and environment. To this end, laboratory tests integrated with numerical simulations were conducted. In the laboratory tests, the CNT was embedded inside the concrete slab and generated the heat up to the target temperature of 60°C in the freezer at temperature of -10°C. Then, the surface temperature was measured to investigate how far the heat transfers on the surface at temperature of above 0°C. Also, three different spacings of 15, 20 and 30cm between CNTs were conducted to determine the maximum allowable spacing of CNT. Along with these experimental tests, heat transferring analysis conducted to validate the test results.

Evaluation on mechanical enhancement and fire resistance of carbon nanotube (CNT) reinforced concrete

Yu, Zechuan,Lau, Denvid Techno-Press 2017 Coupled systems mechanics Vol.6 No.3

To cope with the demand on giant and durable buildings, reinforcement of concrete is a practical problem being extensively investigated in the civil engineering field. Among various reinforcing techniques, fiber-reinforced concrete (FRC) has been proven to be an effective approach. In practice, such fibers include steel fibers, polyvinyl alcohol (PVA) fibers, polyacrylonitrile (PAN) carbon fibers and asbestos fibers, with the length scale ranging from centimeters to micrometers. When advancing such technique down to the nanoscale, it is noticed that carbon nanotubes (CNTs) are stronger than other fibers and can provide a better reinforcement to concrete. In the last decade, CNT-reinforced concrete attracts a lot of attentions in research. Despite high cost of CNTs at present, the growing availability of carbon materials might push the usage of CNTs into practice in the near future, making the reinforcement technique of great potential. A review of existing research works may constitute a conclusive reference and facilitate further developments. In reference to the recent experimental works, this paper reports some key evaluations on CNT-reinforced cementitious materials, covering FRC mechanism, CNT dispersion, CNT-cement structures, mechanical properties and fire safety. Emphasis is placed on the interplay between CNTs and calcium silicate hydrate (C-S-H) at the nanoscale. The relationship between the CNTs-cement structures and the mechanical enhancement, especially at a high-temperature condition, is discussed based on molecular dynamics simulations. After concluding remarks, challenges to improve the CNTs reinforcement technique are proposed.

Thermal effects on nonlinear vibration of a carbon nanotube-based mass sensor using finite element analysis

Kang, D.K.,Kim, C.W.,Yang, H.I. North-Holland 2017 Physica E, Low-dimensional systems & nanostructure Vol.85 No.-

In the present study we carried out a dynamic analysis of a CNT-based mass sensor by using a finite element method (FEM)-based nonlinear analysis model of the CNT resonator to elucidate the combined effects of thermal effects and nonlinear oscillation behavior upon the overall mass detection sensitivity. Mass sensors using carbon nanotube (CNT) resonators provide very high sensing performance. Because CNT-based resonators can have high aspect ratios, they can easily exhibit nonlinear oscillation behavior due to large displacements. Also, CNT-based devices may experience high temperatures during their manufacture and operation. These geometrical nonlinearities and temperature changes affect the sensing performance of CNT-based mass sensors. However, it is very hard to find previous literature addressing the detection sensitivity of CNT-based mass sensors including considerations of both these nonlinear behaviors and thermal effects. We modeled the nonlinear equation of motion by using the von Karman nonlinear strain-displacement relation, taking into account the additional axial force associated with the thermal effect. The FEM was employed to solve the nonlinear equation of motion because it can effortlessly handle the more complex geometries and boundary conditions. A doubly clamped CNT resonator actuated by distributed electrostatic force was the configuration subjected to the numerical experiments. Thermal effects upon the fundamental resonance behavior and the shift of resonance frequency due to attached mass, i.e., the mass detection sensitivity, were examined in environments of both high and low (or room) temperature. The fundamental resonance frequency increased with decreasing temperature in the high temperature environment, and increased with increasing temperature in the low temperature environment. The magnitude of the shift in resonance frequency caused by an attached mass represents the sensing performance of a mass sensor, i.e., its mass detection sensitivity, and it can be seen that this shift is affected by the temperature change and the amount of electrostatic force. The thermal effects on the mass detection sensitivity are intensified in the linear oscillation regime and increase with increasing CNT length; this intensification can either improve or worsen the detection sensitivity.

Evaluation of carbon nanotube-polyamide thin-film nanocomposite reverse osmosis membrane: Surface properties, performance characteristics and fouling behavior

Baek, Y.,Kim, H.J.,Kim, S.H.,Lee, J.C.,Yoon, J. THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2017 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.56 No.-

<P>Carbon nanotube (CNT)-polyamide (PA) thin-film nanocomposite (TFN) reverse osmosis (RO) membranes have been highlighted due to their high water permeability. We evaluated the surface properties, membrane performance and fouling behavior of CNT-PATFN RO membranes. The CNT-PATFN RO membranes showed similar to 30% enhanced water flux, which resulted in a lower energy consumption. The smoother surface of the CNT-PA TFN RO membranes led to less membrane fouling, while its biofouling resistance was insignificant due to less positioned CNTs on the membrane surface. These results provide important insights into the factors optimizing CNT-PA TFN RO membranes as a high performance RO membrane. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>