2019-Sustainable Industrial Processing Summit
SIPS2019 Volume 10: Vayenas Intl. Symp. / Physical Chemistry and its applications for sustainable development
| Editors: | Vayenas Intl. Symp. / Physical Chemistry and its applications for sustainable development Edited by: F. Kongoli, E. Aifantis, C. Cavalca, A. de Lucas Consuegra, A. Efstathiou, M. Fardis, D. Grigoriou, A. Lemonidou, S.G. Neophytides, Y. Roman, M. Stoukides, M. Sullivan, P. Vernoux, X. Verykios, I. Yentekakis |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2019 |
| Pages: | 249 pages |
| ISBN: | 978-1-989820-09-4 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Experimental Investigation and Mathematical Modeling of Triode PEM Fuel Cells
Eftychia Martino1; Alexandros Katsaounis2; Constantinos Vayenas3;1UNIVERSITY OF PATRAS, DEPT. OF CHEMICAL ENGINEERING, Patras, Achaia, Greece; 2DEPARTMENT OF CHEMICAL ENGINEERING, UNIVERSITY OF PATRAS, Patras, Greece; 3UNIVERSITY OF PATRAS, Patras, Greece;
Type of Paper: Regular
Id Paper: 58
Topic: 53
Abstract:
Triode operation of fuel cells is an alternative approach for enhancing fuel cells’ power output under severe poisoning conditions which lead to high overpotentials. This innovation was developed and applied firstly on SOFCs and later on PEMFCs [1-4]. In a triode fuel cell, in addition to the anode and the cathode, there is a third auxiliary electrode in contact with the solid electrolyte (e.g. polymer electrolyte membrane in the case of PEMFCs). This electrode forms, together with the cathode, a second (auxiliary) electric circuit operating in parallel with the conventional main circuit of the fuel cell. The auxiliary circuit runs in the electrolytic mode, pumping ions (i.e. protons in the case of a PEMFC) from the cathode to the auxiliary electrode. This way, imposition of a potential difference between the auxiliary electrode and the cathode permits the primary circuit of the fuel cell to operate under previously inaccessible, i.e larger than 1.23 V, anode - cathode potentials.
The triode operation of humidified PEM fuel cells has been investigated both with pure H2 and with CO poisoned H2 feed over commercial Vulcan supported Pt(30%)-Ru(15%) anodes. It was found that triode operation, which involves the use of a third, auxiliary, electrode, leads to up to 400% power output increase with the same CO poisoned H2 gas feed. At low current densities, the power increase is accompanied by an increase in overall thermodynamic efficiency. A mathematical model, based on Kirchhoff’s laws, has been developed which is in reasonably good agreement with the experimental results. In order to gain some additional insight into the mechanism of triode operation, the model has been also extended to describe the potential distribution inside the Nafion membrane via the numerical solution of the Nernst-Planck equation. Both models and experiments have shown the critical role of minimizing the auxiliary-anode or auxiliary-cathode resistance, and this has led to improved comb-shaped anode or cathode electrode geometries.
Keywords:
Electrochemistry; Electrode potential; Heterogeneous catalysis; Catalyst electrode; Mathematical modeling; Solid electrolyte;References:
[1] S.P. Balomenou, C.G. Vayenas, Triode Fuel Cells and Batteries, J. Electrochem. Soc. 151 (2004) A1874. doi:10.1149/1.1795511.[2] S.P. Balomenou, F. Sapountzi, D. Presvytes, M. Tsampas, C.G. Vayenas, Triode fuel cells, Solid State Ionics. 177 (2006) 2023-2027. doi:10.1016/j.ssi.2006.02.046.
[3] F.M. Sapountzi, S.C. Divane, M.N. Tsampas, C.G. Vayenas, Enhanced performance of CO poisoned proton exchange membrane fuel cells via triode operation, Electrochim. Acta. 56 (2011) 6966-6975. doi:10.1016/j.electacta.2011.06.012.
[4] E. Martino, G. Koilias, M. Athanasiou, A. Katsaounis, Y. Dimakopoulos, J. Tsamopoulos, C.G. Vayenas, Experimental investigation and mathematical modeling of triode PEM fuel cells, Electrochim. Acta. 248 (2017) 518-533. doi:10.1016/j.electacta.2017.07.168.