• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.267-273
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• 2018

From the experiments of various temperature and gas compositions, total resistance which is composed of ohmic resistance, anode resistance, cathode resistance and Nernst loss was calculated wit simple assumption. In this work, the anode and the cathode resistance was modelled with new equation which can account for the correlation between the operating temperature and the gas composition. The proposed model can predict the resistance with maximum error of 2.57% and employed in the simulation of molten carbonate fuel cells.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.68-71
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• 2003

The performance of the Direct Methanol Fuel Cell (DMFC) using multi-layer electrode, which prepared by various anode catalysts and Nafion membranes, was studied for reducing the amount of the metal catalyst loaded in the MEA system. The amount of the catalyst used in this experiment was $3-4 mg/cm^2$ in cathode and $1-2 mg/cm^2$ in anode, respectively. The best performance was to be $230 mS/cm^2$ of MEA3 at $90^{\circ}C$ and 2 bar in this experiment. However, the overall performance of the DMFC was maintained almost the same compared to the general commercial catalyst systems.

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.6-11
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• 2005

Direct borohydrides fuel cell (DBFC) was emerged to complement the problem of DMFC's low performance and methanol crossover to the cathode and to apply the fuel cell to portable and mobile devices. In this study, the characteristics of novel catalysts was tested to establish the electrode preparation process of DBFC. Pt black and carbon supported-Pt by paste method were used as the cathode catalysts. Pt black, carbon supported-Au and $AB_5$ alloy were used as the anode catalysts. The characteristics of the electrodes were analyzed by XRD, SEM, EDS. The performance test of single cell using the electrodes were carried out in order to evaluate the electrode performance. In the result, the maximum power output was obtained as 366 mW/mg when using Pt/C as anode and cathode catalysts.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.646-652
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• 2022

The dead-end anode (DEA) system is a method that closes the anode outlet and supplies fuel by pressure. The DEA method could improve fuel usage and power efficiency through system simplification. However, flooding occurs due to water and nitrogen back diffusion from the cathode to the anode during the DEA operation. Flooding is a cause of decreased fuel cell performance and electrode degradation. Therefore, tthe structure and components of polymer electrolyte membrane fuel cell (PEMFC) should be optimized to prevent anode flooding during DEA operation. In this study, the effect of a porous flow field with metal foam on fuel cell performance and fuel efficiency improvement was investigated in the DEA system. As a result, fuel cell performance and purge interval were improved by effective water management with a porous flow field at the cathode, and it was confirmed that cathode flow field structure affects water back-diffusion. On the other hand, the effect of the porous flow field at the anode on fuel cell performance was insignificant. Purge interval was affected by metal foam properties and shown stable performance with large cell size metal foam in the DEA system.

• Electrical & Electronic Materials
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• v.9 no.9
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• pp.949-953
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• 1996

In this paper, the cathode materials of solid oxide fuel cell were fabricated, and the analysis of TG/DTA, XRD, thermal expansion and electric conductivity were investigated. As a result, thermal expansion coefficient of LSM was not quite different from that of electrolyte. And the performance of LSM(x=0.4) was more excellent than the others.

• Korean Journal of Materials Research
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• v.9 no.11
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• pp.1075-1082
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• 1999

Composite air electrodes of 50/50 vol% LSM- YSZ where LSM =$\textrm{La}_{1-x}\textrm{Sr}_{x}\textrm{MnO}_{3}$(0$\leq$x$\leq$0.5) were prepared by colloidal deposition technique. The electrodes were then examined by scanning electron microscopy (SEM) and studied by ac impedance spectroscopy in order to improve the performance of a solid oxide fuel cell (SOFC). Reproducible impedance spectra were confirmed by using the improved cell, consisting of LSM- YSZ/YSZ/LSM-YSZ. These spectra were a strong function of operating temperature and the stable conditions for the cells were typically reached at $900^{\circ}C$. The typical spectra measured for an air//air cell at $900^{\circ}C$ were composed of two arcs. Addition of YSZ to the LSM electrode led to a pronounced decrease in cathodic resistivity of LSM-YSZ composite electrodes. Polishing the electrolyte surface to eliminate the influences of surface impurities could further reduce cathode resistivity. The cathodic resistivity of the LSM-YSZ electrodes with catalytic interlayer (Ni or Sr) was much smaller than that of LSM-YSZ electrodes without catalytic interlayer. In addition, the cathodic resistivity of the LSM-YSZ electrodes was a strong function of composition of electrode materials, the electrolyte geometry, and applied current.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1206-1207
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• 2015

실내공기 정화를 목적으로 하는 에어컨이나 공기청정기 등의 경우 사용시간이 길어질수록 공기 정화용 필터에 오염물질이 축적되고 수많은 세균이 필터에 증식하게 되며, 이에 대한 유효한 살균방법 중의 하나인 오존살균방법을 이용하게 된다. 오존은 강력한 살균력과 단시간의 환원작용으로 인해 이차적인 잔류 오염물질을 남기지 않는다는 장점이 있다. 본 연구에서는 선대 그물형 전극을 적용한 실내필터 살균용 오존 발생장치의 선전극 개수에 따른 살균을 위한 최적의 오존 발생 특성에 대한 실험을 수행하였다. 실험결과, 실내필터 살균을 위한 최적의 오존농도는 약 2[ppm] 정도가 요구되므로, 본 오존 발생장치의 경우 선전극이 7개이고 인가전압이 18[kV]일 때 1.134[W]의 전력으로 3.527[ppm/W]의 오존을 발생시켰다.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.198-205
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• 2012

Carbon-supported manganese oxide composite were fabricated as an air cathode material for Li-air batteries by hydrothermal method. The composite materials of carbon and manganese oxide were investigated by the implementation of X-ray diffraction, FE-SEM and BET surface area measurer. The manganese oxide synthesized at $170^{\circ}C$ for 12 h has a rod like shape morphology with 40-50 nm long in size. A Lithium-air battery with coin type, of which electrodes are composed of cathode composite materials synthesized $170^{\circ}C$-12 h and lithium metal anode, reveals its first discharge capacity of 3,852 mAh/g and four discharge-charge cycles.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.148-154
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• 2009

With respect to the durability of large scale ($150cm^2$) membrane electrode assembly (MEA) of direct methanol fuel cell (DMFC), degradation phenomena at cathode is monitored and analyzed according to the position on the cathode surface. After constant current mode operation of large scale MEA for 500 hr, the MEA is divided into three parts along the cathode channel; (close to) inlet, middle, and (close to) outlet. The performance of each MEA is tested and it is revealed that the MEA from the cathode outlet of large MEA shows the worst performance. This is due to the catalyst degradation and GDL delamination caused by flooding at cathode outlet of large MEA during the 500 hr operation. Particularly on the catalyst degradation, the loss of electrochemically active surface area (ECSA) of catalyst gets worse along the cathode channel from inlet to outlet, of which the reason is believed to be loss of catalysts by dissolution and migration rather than their agglomeration. The extent of loss in the performance and catalyst degradation has strong relation to the cathode flooding and it is required to develop proper water management techniques and separator channel design to control the flooding.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.518-521
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• 2011

A PEMFC single cell with the active area of $25cm^2$ was used to verify the effect of water management in the anode. Water management is one of the most critical operating variables. In this paper the effect of operating condition change, such as anode humidification and temperature, was investigated under constant current density of $200mA/cm^2$ where possible anode flooding operating area. Also experiments to observe the effect of the anode and cathode stoichiometry change and flow field design on the water management were performed. The water management was effected by the stoichimetry change. The temperature and humidification change also affected the fuel cell performance.