| | 1 | Author
| DietrichW. Abner, Rudolf Holze, Peter Schmittinger | Requires cookie* | | | Title
| Impedance of an Oxygen Reducing Gas-Diffusion Electrode  | | | | Abstract
| The impedance of teflon bonded electrodes was measured in the frequency domain. These electrodes based on activated carbon as electrocatalyst were developed for fuel cell applications. When feeding the electrode with air or oxygen the impedance spectra could be explained by two Nernst diffusion processes and a small charge transfer process. Two methods for separating the measured impedance into partial impedances related to differ ent steps of the electrode reaction are presented. A least square fit procedure is described which has been applied successfully to the impedance analysis of porous electrodes. List o f symbols Symbol Dimension A diffusion factor VT c concentration of diffusing species at electrode surface mol/dm3 cD double layer capacity mF/cm2 d diffusion layer thickness ^m D diffusion coefficient cm2/s f frequency Hz F Faraday constant As/mol i current density mA/cm2 Im(Z) imaginary part of the complex impedance Z Q or Q • cm j imaginary quantity V~1 -R resistance Q or Q ■cm T > ^ o .i m p sum of the resistive parts of the Faradaic impedance Q or Q • cm' R o ,i/ s slope of the potential vs. current density curve at the point of the im pedance measurement Q or Q ■cm' R -d o diffusion resistance Q or Q ■cm' R d charge transfer resistance (equiva lent to Rct) Q or Q ■cm Re(Z) real part of the complex impedance 2 Q ox Q ■cm Rei electrolyte resistance Q z d diffusion impedance Q or Q ■cm ZD charge transfer impedance (equivalent to Zct) f i o r f l ■ cm' z, residual impedance ß o r ß -cm' Y electrochemical equivalent mol/As CO angular frequency (a> = 2 jtF) Hz * Sonderdruckanforderungen an Privatdozent Dr. Diet-rich Wabner, Arbeitsgruppe Angewandte Elek trochemie im | | | |
Reference
| Z. Naturforsch. 39b, 157 (1984); eingegangen am 24. August 1983 | | | |
Published
| 1984 | | | |
Keywords
| Nernst-Impedance, Fuel Cell Electrode, Oxygen Reduction, Gas Diffusion Electrode, Teflon Bonded Electrode | | | |
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| default:Reihe_B/39/ZNB-1984-39b-0157.pdf | | | | Identifier
| ZNB-1984-39b-0157 | | | | Volume
| 39 | |
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