• Title/Summary/Keyword: Storage Capacitance

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Preparation and Electrical Properties of $SrTiO_3$ Thin Films by Plasma Enhanced Metal Organic Chemical vapor Deposition (PE-MOCVD에 의한 $SrTiO_3$ 박막의 제조 및 전기적 특성에 관한 평가)

  • 김남경;윤순길
    • Journal of the Korean Ceramic Society
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    • v.33 no.2
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    • pp.177-182
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    • 1996
  • strontium titanate (SrTiO3) thin films deposited on Pt/MgO were prepared by Plasma Enhanced Metal Orgainc Chemical vapor Deposition (Pe-MOCVD). The crystallinity of SrTiO3 thin films increased with increasing depo-sition temperature and SrF2 second phase disappeared at 55$0^{\circ}C$ The films showed a dielectric constant of 177 and a dissipation factor of 0.0195 at 100 kHz. The variation of capacitance of the films with applied voltage was small showing paraelectric properties. The charge storage density and leakage current density were 40fC/${\mu}{\textrm}{m}$2 and 3.49$\times$10-7 A/cm2 at 0.25 MV/cm, respectively.

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Preparation and Electrochemical Characteristics of CNFs/DAAQ Electrode for Energy Storage

  • Kim Hong-Il;Kim Han-Joo;Choi Weon-Kyung;Osaka Testuya;Park Soo-Gil
    • KIEE International Transactions on Electrophysics and Applications
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    • v.5C no.4
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    • pp.171-175
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    • 2005
  • A new type of supercapacitor was constructed by using carbon nanofibers (CNFs) and DAAQ (l,5-diaminoanthraquinone) oligomer. DAAQ was deposited on the carbon nanofibers by chemical polymerization with ammonium peroxodisulfate (($NH_4)_2S_2O_8$) as oxidant in the 0.1 M $H_2SO_4$. Polymerization reaction was carried out with constant sonication. From the analysis, it is clear that surface of carbon nanofibers was quite uniformly coated with DAAQ. The performance characteristics of the supercapacitors have been evaluated using Cyclic Voltammetry. CNFs/DAAQ based composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system. CNFs/DAAQ composite electrode showed relatively good capacitance (7 Ah/kg) compared to conventional capacitors in the range of $-0.4\~0.4$.

Novel Flexible Supercapacitors Fabricated by Simple Integration of Electrodes, Binders, and Electrolytes into Glass Fibre Separators

  • Yoo, Joung Eun;Bae, Joonho
    • Journal of the Korean Electrochemical Society
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    • v.17 no.4
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    • pp.237-244
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    • 2014
  • We report novel and simple structure of supercapacitors fabricated by using flexible glass fibre separators as templates. This method does not require separate electrodes, binders and high pressure/temperature to build the supercapacitor unit cells as required by the conventional technology. The supercapacitors were fabricated by drop-casting solution mixtures of carbonaceous active materials/gel electrolytes onto two sides of glass fibre separators. Two carbonaceous materials (nanoscaled activated carbons, multi-walled carbon nanotubes) were investigated as electrode materials. The electrochemical measurements reveal that the separatorbased supercapacitors using ACs successfully demonstrated significant mass specific capacitance ($22.3F\;g^{-1}$) and energy density ($9.7Wh\;kg^{-1}$), indicating this method can be useful in fabricating flexible, wearable and stretchable energy storage devices in more straightforward and cost-effective way than current technology.

Charge/Discharge Properties of $V_{2}O_{5}$-Flyash Composite electrode for Supercapacitor (Supercapcitor용 $V_{2}O_{5}$-Flyash Composite 전극의 충방전 특성)

  • 김명산;김종욱;구할본;박복기
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.335-338
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    • 2000
  • Carbon is an attractive candidate for use in eletrochemical supercapacitors that depend on charge storage in the electrode/electrolyte international double layer. Property of an electrical double layer capacitor depend both on the technique used to prepare the electrode and on the current collector structure. The study is to research that V$_2$O$_{5}$-flyash-AC composite electrode for supercapacitor. The discharge capacitance of V$_2$O$_{5}$-flyash-AC(70wt%) in 1st and 50th cycle was 18.6F/g and 15.13F/g at current density of 0.5mA/cm$^2$. The discharge process of V$_2$O$_{5}$-flyash (3 : 97)-AC composite electrode is larger than that others.thers.

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Electrical Properties of Nano Floating Gate Memory for Using Au and$ Au/SiO_2$ Nanoparticles (Au 및 $Au/SiO_2$ 나노입자를 이용한 나노부유게이트메모리 단일소자의 전기적 특성)

  • Park, Byoung-Jun;Kim, Hyun-Suk;Cho, Kyung-Ah;Kim, Sang-Sig
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.107-108
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    • 2005
  • Au and $Au/SiO_2$ nanoparticles(NPs) were synthesized by the colloidal method. The formation of Au and $Au/SiO_2$ NPs was confirmed using high resolution transmission electron microscopy (HRTEM). Synthesized solutions were deposited on Si wafer. The electrical properties of structures were measured using a semiconductor analyzer and a LCR meter. Capacitance versus voltage hysterisis curves showed the charge storage effect by Au and $Au/SiO_2$ NPs.

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Design of a 2kW Bidirectional DC-DC Converter with 99% Efficiency for Energy Storage System (에너지 저장장치를 위한 99% 고효율 2kW급 양방향 dc-dc 컨버터 설계)

  • Lee, Taeyeong;Cho, Younghoon;Cho, Byung-Geuk
    • Proceedings of the KIPE Conference
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    • 2015.11a
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    • pp.85-86
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    • 2015
  • In this paper, the bidirectional DC-DC converter is composed of the 900V Silicon-Carbide(SiC) devices to get high efficiency. The 900V SiC device is better than a similar current rated traditional SiC device. it has a lower drain-source resistance and output capacitance. therefore it can reduce the switching and the conduction losses of the DC-DC converter. The experimental results verify the improvement of efficiency and usefulness of 900V SiC device.

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MONOnS 각 layer층의 두께에 따른 특성

  • Baek, Gyeong-Hyeon;Jeong, Seong-Uk;Jang, Gyeong-Su;Park, Hyeong-Sik;Yu, Gyeong-Yeol;Lee, Won-Baek;Lee, Jun-Sin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.253-253
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    • 2010
  • 유리 기판 상에 시스템 온 패널과 같은 차세대 디스플레이 구현과 평판형 디스플레이의 문제점 해결을 위하여 비휘발성 메모리 소자 등의 전자 소자 집적화와 빠른 구동 속도를 가진 박막트랜지스터가 요구된다. 본 논문에서는 비휘발성 메모리 소자에서 MONOnS 각 layer층의 두께 따른 특성에 대한 연구를 진행하였다. 실험은 ONO 구조를 12.5nm/35nm/2.7nm, 12.5nm/20nm/2.3nm, 8.5nm/10nm/2.3nm, 6.5nm/10nm/1.9nm 의 두께로 증착하였다. ${\Delta}VFB$, Retention time, capacitance을 측정하여 oxide/Nitride/Oxynitride 층의 두께 변화를 통해 최적화된 tunneling layer와 charge storage layer, 그리고 blocking layer의 두께를 알 수 있다.

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Significance of N-moieties in regulating the electrochemical properties of nano-porous graphene: Toward highly capacitive energy storage devices

  • Khan, Firoz;Kim, Jae Hyun
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.129-139
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    • 2018
  • The effects of N doping concentration and dopant moieties on the electrochemical properties of nanoporous graphene and their dependence on annealing temperature are investigated. Four types of N moieties - amide, amine, graphitic-N, and oxidized-N - are obtained, which transformed into pyridinic-N and pyrrolic-N upon annealing. The diffusion coefficient (D') of the ions in the electrode is the maximum at $400^{\circ}C$ because of a high level of N doping, whereas the second highest D0 value is obtained at $700^{\circ}C$ owing to a high level of reduction and N doping. The highest specific capacitance is obtained for the sample annealed at $400^{\circ}C$.

Electroactive Conjugated Polymer / Magnetic Functional Reduced Graphene Oxide for Highly Capacitive Pseudocapacitors: Electrosynthesis, Physioelectrochemical and DFT Investigation

  • Ehsani, A.;Safari, R.;Yazdanpanah, H.;Kowsari, E.;Shiri, H. Mohammad
    • Journal of Electrochemical Science and Technology
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    • v.9 no.4
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    • pp.301-307
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    • 2018
  • The current study fabricated magnetic functional reduced graphene oxide (MFRGO) by relying on ${FeCl_4}^-$ magnetic anion confined to cationic 1-methyl imidazolium. Furthermore, for improving the electrochemical performance of conductive polymer, hybrid poly ortho aminophenol (POAP)/ MFRGO films have then been fabricated by POAP electropolymerization in the presence of MFRGO nanorods as active electrodes for electrochemical supercapacitors. Surface and electrochemical analyses have been used for characterization of MFRGO and POAP/ MFRGO composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. Prepared composite film exhibited a significantly high specific capacity, high rate capability and excellent cycling stability (capacitance retention of ~91% even after 1000 cycles). These results suggest that electrosynthesized composite films are a promising electrode material for energy storage applications in high-performance pseudocapacitors.

The Efficient Design Method Of ROM Accessed Address In Due Sequence (순차 주소 접근 ROM의 효율적인 설계 방법)

  • Kim, Yong-Eun;Kim, Kang-Jik;Cho, Seong-Ik;Chung, Jin-Gyun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.8
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    • pp.18-21
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    • 2009
  • In the digital system, ROM has a large power-consumption and a speed-bottleneck. According to gradual growth of system speed, ROM is demanded to have low-power consumption and high-speed operation design. The ROM adapted in FFT or FIR filter needs method of sequential accessed addressing. We proposed a reduction method for the number of storage cells in this paper. The number of storage cells which is connected with bi-line is reduced by the proposed method so that the capacitance value of bit-time is reduced. In this case, delay time, and power consumption are reduced. Design result of ROM in this paper using the proposed method could reduce up to 86.3% of storage cell '1' compare with conventional method.