• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.73-77
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• 1991

200hrs operational characteristics of the single cell in phosphoric acid fuel cell was studied. The initial performance of single cells was examined as a function of PTFE content of electrode in the range of 30 to 60 wt.%. The cell with the electrode of 40wt.% PTFE was chosen for the 200hrs operation. The cell voltage decay was found to be about 0.5mV/hr for 200hrs operation. These results of cell performance were discussed as related to the internal resistance and the exchange current density of the cell.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.540-546
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• 2010

In order to confirm the effect of Nafion ionomer content in catalyst layer on the performance of PEMFC, we have fabricated several electrodes which were prepared by varying the quantity of Nafion ionomer from 24 wt.% to 39 wt.% in catalyst layer. The effect of Nafion ionomer of each electrode was evaluated with cyclic voltammetry measurement. In addition, cell performance was obtained through single cell test using hydrogen and air. The Pt utilization and performance of single cell were changed by addition of Nafion ionomer to the electrode. Single cell fabricated with 33 wt.% of Nafion ionomer in catalyst layer showed the maximum Pt utilization and performance.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.3
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• pp.208-215
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• 2009

PEMFC stack power output is needed to be around 100 kW to meet the requirements of automotive application and scaling-up the active area of the stack cells will allow a higher power. In the case of scaling-up the active area of cells, it is difficult to obtain uniform in-plane internal conditions such as temperature, relative humidity and stoichiometry of the feed gas. These ununiformity with the location in the cell would affect both the performance and durability of the stack, so it is important to understand phenomena in the cell for improving them. In this study, the current density, electrochemical resistance and performance distribution measurement was performed to understand the ununiformity in a single cell using in-situ method; (1) Current Density Distribution (CDD) Device and (2) Segmented Cell Fixture. The influence of location of feed gas on the performance of a single cell was experimentally measured and discussed by using a segmented single cell which was composed of 8 compartments. The correlation between the location and performance in a single cell was discussed by these two tools and it was extended between the local characterization and the durability in a MEA by comparing the used cell with a fresh one. It was also studied in terms of electrochemistry by Electrochemical Impedance Spectroscopy.

• Advances in Energy Research
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• v.2 no.1
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• pp.21-31
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• 2014

The use of a microporous membrane along with Au/C catalyst for direct glycerol alkaline fuel cell was investigated. In comparison with Nafion 112, the microporous Celgard 3401 membrane provides a better cell performance due to the lower ionic resistance as confirmed by impedance spectra. The single cell using Au/C as anode catalyst prepared by using PVA protection techniques provided a higher maximum power density than the single cell with commercial PtRu/C at $18.65mW\;cm^{-2}$ The short-term current decay studies show a better stability of Au/C single cell. The higher activity of Au/C over PtRu/C was owing to the lower activation loss of Awe. The magnitude of current decay indicates a low problem of glycerol crossover from anode to cathode side. The similar performance of single cell with and without humudification at cathode points out an adequate transport of water through the microporous membrane.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1409-1411
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• 1996

Direct Methanol Fuel Cell(DMFC) using Pt-Ru electrocatlayst and Nafion menbrane can provide high performance if operating conditions are well designed. In this study, operating temperature, pressure, and fuel flow rate were changed to obtain optimum operating conditions of DHFC single cell. Performance of DMFC were increased by the increase of operating temperature. The concentration of fuel methanol was 2.0M $CH_{3}OH$ and pressure difference of cathode and anode was 2 atm were showed maximum performance of DMFC single cell with showing the current density of 160 $mA/cm^2$ at 0.2V cell voltage.

• Korean Journal of Materials Research
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• v.20 no.4
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• pp.187-193
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• 2010

Chromium nitride (CrN) samples with two different layer structures (multilayer and single layer) were coated on bipolar plates of polymer electrolyte membrane fuel cells (PEMFC) using the reactive sputtering method. The effects with respect to layer structure on corrosion resistance and overall cell performance were investigated. A continuous and thin chromium nitride layer ($Cr_{0.48}\;N_{0.52}$) was formed on the surface of the SUS 316L when the nitrogen flow rate was 10 sccm. The electrochemical stability of the coated layers was examined using the potentiodynamic and potentiostatic methods in the simulated corrosive circumstances of the PEMFC under $80^{\circ}C$. Interfacial contact resistance (ICR) between the CrN coated sample and the gas diffusion layer was measured by using Wang's method. A single cell performance test was also conducted. The test results showed that CrN coated SUS316L with multilayer structure had excellent corrosion resistance compared to single layer structures and single cell performance results with $25\;cm^2$ in effective area also showed the same tendency. The difference of the electrochemical properties between the single and multilayer samples was attributed to the Cr interlayer layer, which improved the corrosion resistance. Because the coating layer was damaged by pinholes, the Cr layer prevented the penetration of corrosive media into the substrate. Therefore, the CrN with a multilayer structure is an effective coating method to increase the corrosion resistance and to decrease the ICR for metallic bipolar plates in PEMFC.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1870-1872
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• 1999

Performance of 20-cell stack for direct methanol fuel cell (DMFC) was tested at constant temperature. Electrode evaluation used to the stack was tested by the performance of a single cell. A new composite electrode prepared from active carbon cloth and high porous active carbon was developed for hydrophilic layer of the cell. Characteristics of a single cell using the composite electrode showed the current density of $500mA/cm^2$ at the cell voltage of 0.4V at $120^{\circ}C$. For the operating of 20 days. the cell voltage at constant cell current densty of $100mA/cm^2$ was slightly reduced from 0.62V to 0.53V with the cell voltage decay rate of 14.5%. Power of 20-cell stack at 5.3V, $100^{\circ}C$ was about 180W.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.572-575
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• 2008

Flow-field design has much influence over the performance of proton exchange membrane fuel cell (PEMFC) because it affects the pressure magnitude and distribution of the reactant gases. To obtain the pressure magnitude and distribution of reactant gases in four kinds of flow-field designs without additional measurement equipment, computational fluid dynamics (CFD) analysis was performed. After the CFD analysis, the performance values of PEMFC according to the flow-field configurations were measured via a single cell test. As expected, the pressure differences due to different flow-field configurations were related to the PEMFC performance because the actual performance results showed the same tendency as the results of the CFD analysis. A large pressure drop resulted in high PEMFC performance. So, the single serpentine configuration gave the highest performance. On the other hand, the parallel flow-field configuration gave the lowest performance because the pressure difference between inlet and outlet was the lowest.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.6
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• pp.480-486
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• 2013

In this study, tubular SOFC unit cell with advanced anode current collector was fabricated to improve the cell performance. First, we prepared two types of single cells having the same manufacture processes such as the same electrolyte, electrode coating condition and sintering processes. And then to compare the developed single cell performance with conventional cells, we changed the anode current collecting methods. From the impedance analysis and I-V curve analysis, the cell performance of advanced cell is much higher than that of conventional cell.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1358-1360
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• 1997

In this paper, the performance of Pt/$WO_3$ and Pt-$WO_3$ electrodes was studied for the direct methanol fuel cell. The characteristics of Pt/$WO_3$ electrode which was prepared by using electrodeposition method was tested with half-cell experiment. The characteristics of Pt-$WO_3$/C electrode which was Prepared by using freeze-drying method was tested with a single cell experiment. The performance of DMFC single cell which was prepared by Pt-$WO_3/C$ and Pt/C showed a current density of $32mA/cm^2$ at $110^{\circ}C$ & 0.3V(0.5mg Pt/$cm^2$).