Voltage degradation

Sholklapper et al. [204] studied the structure and performance stability of a nanoparticle-infiltrated LSM in porous scandia-stabilized zirconia (SSZ) electrode at 650°C. The infiltrated LSM particles were 100 nm in diameter and some orientation alignment of the LSM nanoparticles within SSZ was observed after the cathodic polarization at 150 mAcnr2 for 500 h. However, there is no voltage degradation under the conditions studied. 

Westinghouse AES cells have shown less than 0.2 % voltage degradation per 1000 hours in a 25 kW stack operated for over 13,000 hours (22). 

There are discrepancies in the amounts of harmful species tolerance that fuel cell developers establish, even for similar type fuel cells. These discrepancies are probably due to electrode design, microstructure differences, or in the way developers establish tolerance. There are some cases where the presence of certain harmful species causes immediate performance deterioration. More often, the degradation occurs over a long period of time, dependant on the developer s allowable voltage degradation rate on exposure to the specific harmful species. Here, the developer establishes an estimated cell life based on economics. The permissible amount of the harmful constituent is then determined based on its life effects. 

Yu, P.T. et ah. The impact of carbon stability on PEM fuel cell startup and shutdown voltage degradation, ECS Trans., 3, 797, 2006. 

Fig. 9.13 Top voltage degradation in a DMFC during a constant current (80 mA.cm ) test. Bottom effect of air break (4 s every 100 s) on the long-term performance of air-pulsed DMFC (Reproduced from Ref [120] with permission)...

Fowler M, Maim RF, Amphlett JC, Peppley BA, Roberge PR (2002) Incorporation of voltage degradation into a generalized steady state electrochemical model for a PEM fuel cell. J Power Sources 106 274-283... 

Polyaniline films were studied by Grata and Buttry [88], who elec-tropolymerized and cycled the films in place on a QCM. Anions were observed to be inserted and removed during oxidation and reduction, respectively, in aqueous solutions. There was some additional insertion oF as a function of pH and voltage. Degradation of the film was... 

Trade-off between efficiency and degradation performance Bus city driving cycles effect on voltage degradation Review of literature on effects and potential mitigation of various degradation modes... 

Difference between reversible and irreversible voltage degradation under open-circuit conditions Sub-zero operation effect on ice formation Driving cycle dynamic loading... 

Lu L, Ouyang M, Huang H, Pei P and Yang F (2007), A semi-empirical voltage degradation model for a low-pressure proton exchange membrane fuel cell stack under bus city driving cycles, Journal of Power Sources, 164,306-314. 

A., and Aslanides, A. (2008) A review on PEM voltage degradation associated with... 

Fowler M, Mann RF, Amphlett JC, Peppley BA, Roberge PR. Reliability issues and voltage degradation. In Handbook of fuel cells fundamentals, technology and applications, volume 3. Vielstich W, Lamm A, Gasteiger HA, editors. New York Wiley, 2003 663-77. 

Fig. 13.3 Stack voltage degradation during life membranes with 2 wt% of Ti02-Current density = 0.2...

The effect of D4-siloxane on the stack performance was studied by varying the D4 concentration from 69 ppb (v) up to 1.0 ppm(v) and strong voltage degradation even at the lowest concentrations was observed. The effect of the contaminant starts immediately suggesting the poisoning of the electrochemicaUy active... 

NUREG-0800, BTP PSB-1, "Adequacy of station electric distribution system voltages (Degraded... 

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