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Adsorptionshysterese von Phosphorsäure in Polybenzimidazol‐Hochtemperatur‐Polymerelektrolytmembran‐Brennstoffzellen |
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| Authors: | Ashish Kamat Dr. Olaf Klein Dr. Mirko Herrmann Jun.‐Prof. Dr.‐Ing. Ulrike Krewer Prof. Dr.‐Ing. Stephan Scholl |
| Affiliation: | 1. Konzernforschung Volkswagen AG, Am Krainhop 5, 38550 Isenbüttel, Deutschland;2. Max‐Planck‐Institut für Dynamik komplexer technischer Systeme, Sandtorstra?e 1, 39106 Magdeburg, Deutschland;3. Otto‐von‐Guericke‐Universit?t Magdeburg, Portable Energiesysteme, Universit?tsplatz 2, 39106 Magdeburg, Deutschland;4. Technische Universit?t Braunschweig, Institut für Chemische und Thermische Verfahrenstechnik, Langer Kamp 7, 38106 Braunschweig, Deutschland |
| Abstract: | During thermal cycling investigations on polybenzimidazole high temperature polymer electrolyte membrane fuel cells a stationary hysteresis behavior of the cell current was observed. With the Tafel equation a correlation to the surface oxygen concentration on the platinum is given. Because no such hysteresis of oxygen adsorption on platinum is known a new theory is proposed. This theory is based on the thermal dependence of the surface coverage of phosphoric acid on platinum. The resulting adsorption hysteresis is confirmed as being the reason for the observed cell current hysteresis by the results of a Monte Carlo simulation. This is validated through a qualitative comparison with measured data from aged test cells. |
| Keywords: | Adsorption Hysterese Oberflä chenbedeckung PBI‐Hochtemperatur‐PEM‐Brennstoffzellen Phosphorsä ure Tafelgleichung Adsorption Hysteresis PBI high temperature PEM fuel cell Phosphoric acid Surface coverage Tafel equation |