@article { ISI:000240393500018, title = {Analysis of single PEM fuel cell performances based on current density distribution measurement}, journal = {Journal of Fuel Cell Science and Technology}, volume = {3}, number = {3}, year = {2006}, note = {1st Conference on European Fuel Cell Technology and Applications (EFC2005), Rome, ITALY, DEC 14-16, 2005}, month = {AUG}, pages = {351-357}, publisher = {Univ Perugia; Italian Agcy New Technol \& Environm; Amer Soc Mech Engineers}, type = {Article}, address = {THREE PARK AVE, NEW YORK, NY 10016-5990 USA}, abstract = {

A new in situ measurement method of mapping the current density distribution in polymer electrolyte fuel cells (PEFC) is used to analyze the performance of a fuel cell under different operating conditions. The present method is useful in investigating the current density distribution in a single cell as well as a stack, which carries the information about the local reactant activity over the electrode area It was found that the current density close to the gas inlets is strongly influenced by the reactants{\textquoteright} relative humidity. The performance close to the gas outlets is greatly influenced by the inlet gas pressures and the stoichiometry factors of the reactant gases, mainly on the cathode side. It was also observed that the performance of the fuel cell drops with the increase in operating temperature if the reactant gases are not sufficiently humidified.

}, keywords = {current density distribution, fuel cell performance, PEFC}, issn = {1550-624X}, doi = {10.1115/1.2173664}, author = {Ghosh, P. C. and Wuester, T. and Dohle, H. and Kimiaie, N. and Mergel, J. and Stolten, D.} } @article { ISI:000246978800037, title = {DMFC at low air flow operation: study of parasitic hydrogen generation}, journal = {Electrochimica Acta}, volume = {52}, number = {19}, year = {2007}, month = {MAY}, pages = {6060-6067}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

In this paper, the effect of hydrogen generation in direct methanol fuel cells (DMFC) is described. Under certain operating conditions hydrogen generation occurs in DMFC causing an additional methanol consumption and a decrease of the cell voltage. For the present experiments a segmented cell with an active area of 244 cm 2 is used. The cell has 196 segments which are regularly distributed on the whole area. By this experimental setup hydrogen generation was found in regions with insufficient air supply. Hydrogen generation was analyzed by systematically applying different air flow rates and detecting the local current densities. The theory for hydrogen generation is confirmed by the results obtained from the segmented cell. A correlation between open circuit voltage (OCV), air flow rate and hydrogen generation was observed. Furthermore, half-cell measurements with different methanol concentrations were performed and used for analyzing the processes during hydrogen generation. The work clearly indicates the importance of sufficient cathode air supply for DMFC. Starved cathode areas not only do not contribute to the overall current generation but in addition reduce the power and efficiency by the parasitic generation of hydrogen. (C) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {DMFC, Efficiency, electrolytic hydrogen evolution, oxygen depletion, side-effects}, issn = {0013-4686}, doi = {10.1016/j.electacta.2007.03.067}, author = {Dohle, H. and Mergel, J. and Ghosh, P. C.} } @article { ISI:000254804700001, title = {2(7-3) fractional factorial optimization of polybenzimidazole based membrane electrode assemblies for H-2/O-2 fuel cells}, journal = {Journal of Applied Electrochemistry}, volume = {38}, number = {5}, year = {2008}, month = {MAY}, pages = {583-590}, publisher = {SPRINGER}, type = {Article}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

We describe the usefulness of a statistical fractional factorial design to obtain consistent and reproducible behavior of a membrane-electrode-assembly (MEA) based on a phosphoric acid (PA) doped polybenzimidazole (PBI) membrane, which allows a H-2/O-2 fuel cell to operate above 150 degrees C. Different parameters involved during the MEA fabrication including the catalyst loading, amount of binder, processing conditions like temperature and compaction load and also the amount of carbon in the gas diffusion layers (GDL) have been systematically varied according to a 2(7-3) fractional factorial design and the data thus obtained have been analyzed using Yates{\textquoteright}s algorithm. The mean effects estimated in this way suggest the crucial role played by carbon loading in the gas diffusion layer, hot compaction temperature and the binder to catalyst ratio in the catalyst layer for enabling continuous performance. These statistically designed electrodes provide a maximum current density and power density of 1,800 mA cm(-2) and 280 mW cm(-2), respectively, at 160 degrees C using hydrogen and oxygen under ambient pressure.

}, keywords = {Carbon loading, Fractional factorial optimization, MEA, PBI, PEMFC}, issn = {0021-891X}, doi = {10.1007/s10800-007-9475-1}, author = {Kannan, Ramaiyan and Islam, Md. Nazrul and Rathod, D. and Vijay, M. and Kharul, Ulhas K. and Ghosh, P. C. and Vijayamohanan, K.} }