• Title/Summary/Keyword: electrical double layer capacitor

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Preparation and Electrochemical Characteristics of DAAQ/CNFs Composite electrode for Supercapacitor (DAAQ가 코팅된 슈퍼커패시터용 CNFs전극 활물질의 제조 및 전기 화학적 특성)

  • Kim, Hong-Il;Choi, Weon-Kyung;Park, Soo-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.1226-1229
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    • 2004
  • Supercapacitors, also known as electrochemical capacitors, are being extensively studied due to an increasing demand for energy-storage systems. These devices offer many advantages over conventional secondary batteries, which include the ability of fast charge propagation, long cycle-life and better storage efficiency. That is to say supercapacitor bridges the gap between conventional capacitors and batteries. A new type electric double layer capacitor (EDLC) also called supercapacitors. Recently, supercapacitors concerns about their high power density and energy density. So we experiment with EDLC by using carbon nanofibers (CNFs) and DAAQ(1,5-diaminoanthraquinone) electrode. The electrode for supercapacitor was prepared by synthesis of DAAQ covered CNFs. CNFs could be covered with very thin DAAQ oligomer from the results of CV, XRD, DSC, SEM images, and TEM images. Dissolved electrode active material in NMP solution has been drop-coated on carbon plate. Its electrochemical characteristics were investigated by cyclic voltammograms. And compared with different electrolyte of aqueous type. As a result, CNFs coated by DAAQ composite electrode showed relatively good electrochemical behaviors with respect to specific capacity and scan rate dependency.

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Development of Charger/Discharger to Test Performance for EDLC (EDLC를 위한 성능시험용 충방전기 개발)

  • Kim, Geum-Soo;Moon, Jong-Hyun;Cho, Hyun-Cheol;Kim, Dong-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.7
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    • pp.16-22
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    • 2012
  • With the increase of consumption of new renewable energy, the use of Electric Double Layer Capacitor(EDLC) is being gradually widened as the next generation energy storage device. In order to expand the market of EDLC which is recently receiving a lot of attraction as a new promising area, development of a charge/discharge cycle tester to measure and test performance, is essential. Therefore, this research designed a circuit to measure capacity and internal resistance and a circuit to measure voltage maintenance properties, based on EDLC's basic charging/discharging properties so it is able to measure the state of charge and discharge at high speed. When evaluating performance characteristics, the 5[V]/100[A] prototype-EDLC charge/discharge testing system developed for this research showed ${\pm}0.1$[%] of accuracy of voltage and current measurement. It was also proved that the developed charge/discharge testing system for EDLC can be applied to the actual industry, when testing the entire system using a program produced for data monitoring and acquisition.

Electrochemical Characteristics of Electric Double Layer Capacitor using heat treated Activated Carbon at $H_2$ Atmosphere (수소처리 활성탄소를 사용한 EDLC의 전기화학적 특성)

  • Lee, Sun-Young;Kim, Ick-Jun;Moon, Seong-In;Kim, Hyun-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.246-247
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    • 2005
  • 본 연구에서는 활성탄소의 표면 작용기와 전해액, 결합제의 분해반응을 줄여서 내구성을 향상시키기 위해 $H_2$ 기체의 Spill-Over 현상을 이용하여 활성탄소 표면의 작용기를 치환시킨 시료를 사용하여 전극을 구성하였다. $H_2$기체로 활성탄소를 700$^{\circ}C$에서 열처리한 결과, 원소 분석기 (Elemental Analyzer)를 이용한 원소 분석 시에 산소의 비율이 1.4%로 활성탄소의 2.44%에 비해 감소함을 알 수 있었고, Carbon의 비율이 700$^{\circ}C$에서 94.3%로 증가함을 알 수 있었다. 또한, 활성탄소를 사용한 전극을 1.2M TEABF$_4$/Acetonitrile 전해액을 사용하여 커패시터를 구성 했을 때, 1kHz의 AC저항은 700$^{\circ}C$에서 열처리한 활성탄소가 0.58\Omega$로 활성탄소의 1.300에 비해 양호한 전기화학 특성을 나타내었다.

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Electrochemical Characteristics of DAAQ/CNFs electrode for Supercapacitor (슈퍼커패시터용 DAAQ/CNFs 전극의 전기화학적 특성)

  • Kim, Hong-Il;Choi, Weon-Kyung;Park, Soo-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1184-1187
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    • 2003
  • Electrochemical capacitors are becoming attractive energy storage systems particularly for applications involving high power requirements such as hybrid systems consisting of batteries and electrochemical capacitors for electric vehicle propulsion. A new type electric double layer capacitor (EDLC) was constructed by using carbon nanofibers (CNFs) and DAAQ(1,5-diaminoanthraquinone) electrode. Carbonaceous materials are found in variety forms such as graphite, diamond, carbon fibers etc. While all the carbon nanofibers include impurities such as amorphous carbon, nanoparticles, catalytic metals and incompletely grown carbons. We have eliminated of Ni particles and some carbonaceous particles in nitric acid. Nitric acid treated CNFs could be covered with very thin DAAQ oligomer from the results of CV and TG analyses and SEM images. DAAQ oligomer film exhibited a specific capacity as 45-50 Ah/kg in 4M $H_2SO_4$. We established Process Parameters of the technique for the formation of nano-structured materials. Furthermore, improved the capacitive properties of the nano structured CNFs electrodes using controlled solution chemistry. As a result, CNFs coated by DAAQ composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system with respect to specific capacity and scan rate dependency.

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A Study on Characteristic of Hybrid PCS for Solar Power Generation Considering on a Residential Lithium Battery ESS. (가정용 리튬배터리 ESS를 고려한 태양광 발전 하이브리드 PCS 특성에 관한 연구)

  • Hwang, Lark-Hoon;Na, Seung-kwon;Choi, Byung-Sang
    • Journal of Advanced Navigation Technology
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    • v.26 no.1
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    • pp.35-45
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    • 2022
  • In this paper, we modeled the devices used easily in PV system circuits. In addition, for full operation of the photovoltaic system, a complete operation system for the DC-DC buck-boost converter and the MPPT control system was modeled and simulated to confirm good operation. we were constructed an actual system with the same conditions in the simulation and experimented. The purpose is to confirm the stable power supply through the load leveling by presenting the PCS considering ESS of photovoltaic power generation. we will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. As a result, we proposed a single-phase 3 kW grid-connected solar power converter.

Simulation analysis of a renewable energy based microgrid using RTDS (RTDS를 이용한 신재생에너지 기반 마이크로그리드 시뮬레이션 해석)

  • Heo, Se-Rim;Kim, Gyeong-Hun;Lee, Hyo-Guen;Hwang, Chul-Sang;Park, Min-Won;Yu, In-Keun;Park, Jung-Do;Yi, Dong-Young;Lee, Sang-Jin
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.143-144
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    • 2011
  • Due to enhanced demands on quality, security and reliability of the electric power energy system, a microgrid has become a subject of special interest. In this paper, output characteristics of energy storage system (ESS) with an electric double layer capacitor (EDLC) and battery energy storage system (BESS) of a renewable energy based microgrid were analyzed under grid-connected and islanded operation modes. The microgrid which consists of photovoltaic and wind power turbine generators, diesel generator, ESS with an EDLC, BESS and loads was modeled using real time digital simulator. The results present the effective control patterns of the microgrid system.

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Determination of the Hybrid Energy Storage Capacity for Wind Farm Output Compensation (풍력발전단지 출력보상용 하이브리드 에너지저장장치의 용량산정)

  • Kim, Seong Hyun;Jin, Kyung-Min;Oh, Sung-Bo;Kim, Eel-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.33 no.4
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    • pp.23-30
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    • 2013
  • This paper presents the determination method of the hybrid energy storage capacity for compensating the output of wind power when disconnecting from the grid. In the wind power output compensation, a lot of charging and discharging time with lithium-ion battery will be deteriorated the life time. And also, this fluctuation will cause some problems of the power quality and power system stability. To solve these kind of problems, many researchers in the world have been studied with BESS(Battery Energy Storage System) in the wind farm. But, BESS has the limitation of its output during very short term period, this means that it is difficult to compensate the very short term output of wind farm. Using the EDLC (Electric Double Layer Capacitor), it is possible to solve the problem. Installing the battery system in the wind farm, it will be possible to decrease the total capacity of BESS consisting of HESS (Hybrid Energy Storage System). This paper shows simulation results when not only BESS is connected to wind farm but also to HESS. To verify the proposed system, results of computer simulation using PSCAD/EMTDC program with actual output data of wind farms of Jeju Island will be presented.

Optimal Porous Structure of MnO2/C Composites for Supercapacitors

  • Iwamura, Shinichiroh;Umezu, Ryotaro;Onishi, Kenta;Mukai, Shin R.
    • Korean Journal of Materials Research
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    • v.31 no.3
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    • pp.115-121
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    • 2021
  • MnO2 can be potentially utilized as an electrode material for redox capacitors. The deposition of MnO2 with poor electrical conductivity onto porous carbons supplies them with additional conductive paths; as a result, the capacitance of the electrical double layer formed on the porous carbon surface can be utilized together with the redox capacitance of MnO2. However, the obtained composites are not generally suitable for industrial production because they require the use of expensive porous carbons and/or inefficient fabrication methods. Thus, to develop an effective preparation procedure of the composite, a suitable structure of porous carbons must be determined. In this study, MnO2/C composites have been prepared from activated carbon gels with various pore sizes, and their electrical properties are investigated via cyclic voltammetry. In particular, mesoporous carbons with a pore size of around 20 nm form a composite with a relatively low capacitance (98 F/g-composite) and poor rate performance despite the moderate redox capacitance obtained for MnO2 (313 F/g-MnO2). On the other hand, using macro-porous carbons with a pore size of around 60 nm increases the MnO2 redox capacitance (399 F/g-MnO2) as well as the capacitance and rate performance of the entire material (203 F/g-composite). The obtained results can be used in the industrial manufacturing of MnO2/C composites for supercapacitor electrodes from the commercially available porous carbons.

Preparations of PAN-based Activated Carbon Nanofiber Web Electrode by Electrostatic Spinning and Their Applications to EDLC (정전방사에 의한 PAN계 활성화 탄소 나노섬유 전극 제조와 EDLC 응용)

  • Kim, Chan;Kim, Jong-Sang;Lee, Wan-Jin;Kim, Hyung-Sup;Edie, Dan D.;Yang, Kap-Seung
    • Journal of the Korean Electrochemical Society
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    • v.5 no.3
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    • pp.117-124
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    • 2002
  • Poly(acrylonitrile)(PAN) solutions in dimethylformamide(DMF) were electrospun to prepare webs consisting of 400nm ultra-fine fibers. The webs were oxidatively stabilized, activated by steam and resulted to be activated carbon fibers(ACFs). The specific surface area was $800\~1230 m^2/g$, which showed a trend of a decrease of the surface area with an increase in activation temperature, showing opposite behavior to the other ACFs. The activation energy of the stabilized fibers for the steam activation was determined as 29.2 kJ/mol to be relatively low indicating the easier activation than that of other carbonized fibers. The ACF webs were characterized by pore size and specific surface uea which would be related to the specific capacitance of the electrical double layer capacitor (EDLC). The specific capacitances measured were 27 F/g, 25 F/g, 22 F/g at the respective activation temperature of $700^{circ}C,\;750^{\circ}C\;800^{\circ}C$, showing similar trend with the specific surface area i.e., the higher activation temperature was, the lower specific capacitance resulted.

A Study of Seamless Power Supply using EDLC on Battery Change of Smartphone (EDLC를 이용한 스마트폰의 배터리 교환 시 연속적 전원 공급에 관한 연구)

  • Choi, Sang-Hun;Lee, Yong-Sung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.12
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    • pp.61-67
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    • 2015
  • Certainly, we are living in a true mobile society. At the end of 2014, approximately 40million 560thousand people are subscribed to smartphone services in Korea, using more than 2000MB of mobile data per a person. The use of smartphone is expected to increase. Moreover, smartphone moves toward becoming a requisite for modern people. Under the circumstances, high-speed communication services such as LTE provide high quality services anywhere and anytime and, furthermore, the development of high performances of the application makes the life patterns of modern people link directly to smartphone. Almost every day, new creative services are being introduced and the demands of on-line streaming services such as high-performance game and YouTube are increasing day after day. However, although smartphones are getting smarter and high quality services are rapidly growing, consumers still complain about the insufficient usage time caused by the capacity of batteries. In order to solve this problem, this thesis suggests EDLC(Electric Double-Layer Capacitor) uses as a supplemental power supply to keep the continuity of work while switching batteries. Through this approach, the running time of smartphone becomes longer as the number of batteries without power off and the purpose of this study is to maximize the convenience of using smartphone by eliminating the initialization of memories and the loss of time of rebooting while batteries are switched.