• Journal of the Korean Electrochemical Society
• /
• v.5 no.4
• /
• pp.192-196
• /
• 2002

Ionic liquids based on l-ethyl-3-methylimidazolium cation $(EMI^+)$ and inorganic or organic anions containing fluorine atoms were applied to electrolyte materials for double-layer capacitors. The double-layer capacitors composed of a pair of activated carbon electrodes and an ionic liquid selected from $EMIBF_4,\; EMINbF_6,\;EMITaF_6,\;EMICF_3SO_3,\;EMI(CF_3SO_2)_2N,\;and\;EMI(C_2F_5SO_2)_2N$ showed inferior low-temperature characteristics to those of a conventional nonaqueous electrolyte based on propylene carbonate (PC) solvent. On the other hand, the capacitor using $EMIF{\cdot}2.3HF$ showed excellent low-temperature characteristics due to its high conductivity at low temperatures, however, it had a lower working voltage $(\~2V)$ than the conventional nonaqueous counterpart $(\~3V)$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.06a
• /
• pp.211-214
• /
• 1998

The composite of polyvinylalcohol(PVA) and lithium salts(LiBF$_4$) is prepared for a solid-state electrolyte of electric double layer capacitor. The composite shows a good ionic conductivity. The solid-state electric double layer capacitor is made of PVA-LiBF$_4$ composite, activated carbon and etc.. As evaluation of characteristics of capacitor, capacitance change which measured by charge-discharge test with 2.2V~0V at 8$0^{\circ}C$ for 800 hours, was about 10%. The gravimetric and volumetric capacitance were 10.0 F/g~30.0 F/g and 16.0F/㎤~F/㎤, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.1
• /
• pp.107-111
• /
• 2004

This work describes the effect of composite conductor on the characteristics of electric double layer capacitor. Test cell, which was fabricated with conducting composite consisted of 80％ of SPB and 20％ of VGCF, exhibits the better tate capability and the lower resistance than those of the cells fabricated with single electronic conductor. These enhanced properties could be related with the decrease of contact resistance between the activated carbon powders.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1821-1823
• /
• 1999

Carbon is an attractive material on electro double capacitor which depend on charge storage in the electrode/electrolyte interfacial double layer. Carbonaceous material for double layer capacitor can be obtained from carbon powder, fiber, film and porous carbon sheet. The capacitance of electrodes using an activated carbon was influenced by a filling density of the carbon, thickness and internal resistance of the electrode. In this study. to reduce internal resistance and increase electric conductivity of the electrode. activated carbon/carbon(AC/C) composite electrode was fabricated. The capacitors which have energy densities of 68F/g(at $30^{\circ}C$), 109F/g(at $60^{\circ}C$) and $68F/cm^3$(at $30^{\circ}C$), $111F/cm^3$(at $60^{\circ}C$) were fabricated by using AC/C composite electrodes.

• Journal of Advanced Navigation Technology
• /
• v.19 no.5
• /
• pp.433-439
• /
• 2015

Recently, Interest in power the quality was increased because of increasing the use of sensitive load equipment into an electrical disturbance such as computer, Electricity, Electronics, Telecommunications and semiconductor device. In addition, To enhance power quality, the instantaneous voltage drop occurred in precision load equipment is a need for proper compensation. In order to solve the problem, The developed dynamic voltage restorer (DVR) using an electric double layer capacitor (EDLC) has been applied. In this paper, We will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. Also, As a emergency luminaires of emergency power supply that we can support more than 10 years of life was confirmed the applicability of hybrid capacitor.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.59-60
• /
• 2013

슈퍼캐패시터(Super Capacitor) 또는 울트라 캐패시터(Ultra Capacitor) 등으로 불리우는 전기 이중층 캐패시터(EDLC, Electric Double Layer Capacitor)는 기존 콘덴서보다 월등한 용량 특성을 가지며, 전극과 전해질의 화학반응을 이용하던 이차전지들과 달리 주로 계면반응을 사용한 축전원리를 이용하여 높은 출력밀도와 충방전 효율, 무제한에 가까운 사이클 특성을 가지고 있다. 또한 전류변화에 안정적이어서 기존의 이차전지와는 달리 보호회로를 생략할 수 있기 때문에 단순한 회로 구성이 가능하고 전극활물질로서 탄소재를 사용하여 환경 친화적인 특성을 가진 차세대 에너지저장장치라고 할 수 있다. 특히 50만 사이클이라는 우수한 수명특성으로 인해 기존의 이차전지가 사용되기 어려운 다양한 분야에 적용이 늘어가고 있는 추세에 있다.

• Korean Chemical Engineering Research
• /
• v.50 no.6
• /
• pp.1043-1048
• /
• 2012

In this study, activated carbons (ACs) were modified as electrode materials for an electric double layer capacitor (EDLC) by controlling oxygen- and nitrogen-containing functional groups. The morphological and chemical properties of ACs were analyzed through scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectrometer, automatic elemental analyzer (EA) and Boehm titration. Also, charge/discharge tests were performed to investigate the EDLC performance. Oxygen- and nitrogen-containing functional groups were introduced on the surface of ACs through acid and urea treatments, respectively. ACs with nitrogen-containing functional groups showed 2 mA increase of gravimetric discharge capacity and quick achievement of maximum charge/discharge performance. However, ACs with oxygen-containing functional groups showed low discharge capacity and its gradual decrease during further cyclic test, since the functional groups interrupted adsorption/desorption of charges in the electrolyte on the surface of ACs.

• Journal of the Korean Electrochemical Society
• /
• v.9 no.1
• /
• pp.10-18
• /
• 2006

This article is concerned with the overview of the activated carbon fibers. Firstly, this review provides a comprehensive survey of the overall processes for the synthesis of the activated carbon fibers from the carbonaceous materials. Subsequently, the physicochemical properties such as pore structures and surface oxygen functional groups of the activated carbon fibers were discussed in detail. Finally, as electrochemical applications of the activated carbon fibers to electrode materials for electric double-layer capacitor (EDLC), the electrochemical characteristics of the activated carbon fiber electrodes and the various methods to improve the capacitance and rate capability were introduced. In particular, the effect of pore length distribution (PLD) on kinetics of double-layer charging/discharging was discussed based upon the experimental and theoretical results in our work. And then we discussed in detail the applications of the activated carbon fibers to adsorbent materials for purification of liquid and gas.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.9
• /
• pp.1493-1496
• /
• 2016

This paper proposes a system for reducing the standby power consumption in using the consumer electronic devices such as a television, a home theater, a set-top box, or a DVD player. The system is consisted of a flyback converter, monitoring circuits, a relay and a micro-processor. The proposed system can reduce the standby power consumption by disconnecting the AC input and the consumer devices can be turned on with a remote control. The proposed standby power system consumes the low power to receive the infrared signal from the remote controller. Furthermore, a electronic double layer capacitor is used to store the energy with high efficiency. The proposed power system can operate the 플라이백 converter to charge the electronic double layer capacitor and connect the AC input to the consumer electronic devices. The proposed power circuit can reduce the standby power consumption in AV devices without increasing the cost. The prototype is implemented to verify the system with the commercialized products.

• Korean Journal of Materials Research
• /
• v.25 no.3
• /
• pp.132-137
• /
• 2015

The effects of the mixing of an active material and a conductive additive on the electrochemical performance of an electric double layer capacitor (EDLC) electrode were investigated. Coin-type EDLC cells with an organic electrolyte were fabricated using the electrode samples with different ball-milling times for the mixing of an active material and a conductive additive. The ball-milling time had a strong influence on the electrochemical performance of the EDLC electrode. The homogeneous mixing of the active material and the conductive additive by ball-milling was very important to obtain an efficient EDLC electrode. However, an EDLC electrode with an excessive ball-milling time displayed low electrical conductivity due to the characteristic change of a conductive additive, leading to poor electrochemical performance. The mixing of an active material and a conductive additive played a crucial role in determining the electrochemical performance of EDLC electrode. The optimal ball-milling time contributed to a homogeneous mixing of an active material and a conductive additive, leading to good electrochemical performance of the EDLC electrode.