Cathode degradation

Degradation of the cathode catalyst is the main contributor to performance degradation in the fuel cell in the absence of contamination effects. This will be discussed in terms of degradation of the catalyst metal itself as well the corrosion of the carbon catalyst support. 

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Matsuzaki, Yasuda (2001), Dependence of SOFC Cathode Degradation by Chromium-containing Alloy on Compositions of Electrodes and Electrolytes ,). Electrochem. Soc., 148, A126. 

In this work a physical processes, which lead to variations in cathode work function, is considered. Also the numerical model, which is described field emission cathode degradation due to these processes, is proposed. 

The cathode degrades by the formation of black spots if the device is operated under ordinary ambient conditions [109], The black spots are circular in shape and do not emit any light. With aging the average size of the spots increases but their number remains constant as shown in Fig. 4.10(a). SEM measurements showed that there was a pinhole at the center of each spot. The black spots are cause by the pinholes in the metal. The number of the black spots decreased as the thickness of the metal layer was increased as shown... 

Parry V, BerthomS G, Joud J-C, Lemaire O, Franco AA. XPS investigations of the proton exchange membrane fuel cell active layers aging characterization of the mitigating role of an anodic CO contamination on cathode degradation. J Power Sources 2011 196(5) 2530—8. 

Platinum catalyst Toluene-induced cathode degradation Li et al., 2008... 

Aoki T, Matsunaga A, Ogami Y, Maekawa A, Mitsushima S, Ota KI and Nishikawa H (2010),The influence of polymer electrolyte fuel cell cathode degradation on the electrode polarization, Journal of Power Sources, 195,2182-2188. 

During cell overcharge, a part of the irreversible energy 7a F and - t7c 1 rn y be used to overcome the activation energy of anode and cathode degradation, respectively, and of electrolyte anodic oxidation and cathodic reduction reactions, which account for cell selfdischarge and aging [11,21-24],... 

To reach the requirements of performance and durability for both automotive and stationary PEFC appUcations [20], catalyst durability has become an important issue both for of academic and industrial R D. Cathode degradation in operating PEFCs mainly occurs tmder transient conditions, leading both to Pt dissolu-tion/degradation and carbon-support corrosion. At typical operational pH conditions and above 0.9 V, two main mechanisms lead to Pt degradation (i) diffusion of dissolved Pt species... 

Matsuzaki Y, Yasuda I (2001) Dependence of SOFC cathode degradation by chromium-containing alloy on compositions of electrodes and electrolytes. J Electrochem Soc 148(2) A126-A131... 

Fig. 18.6 Temperature dependence of cathode degradation (a) Cr poisoning on LSM cathodes (From [34]) (b) SO2 poisoning on SSC cathode (From [53])...

Li, H., et al. 2008. Polymer electrolyte membrane fuel ceU contamination Testing and diagnosis of toluene-induced cathode degradation. /. Power Sources 185 272-279. 

FIGURE 8.14 Voltage versus time curves with various levels of toluene at different current densities. Cell temperature = 80°C, Relative humidity = 80%, 30 psi back pressure, stoichiometry 1.5/3.0 for Hj/air. (Reprinted from Journal of Power Sources, 185, Li, H. et al. Polymer electrolyte membrane fuel cell contamination Testing and diagnosis of toluene-induced cathode degradation, 272-279, Copyright (2008), with permission from Elsevier.)... 

Li, H., Zhang, J. L., Shi, Z. et al. 2009. PEM fuel cell contamination Effects of operating conditions on toluene-induced cathode degradation. Journal of the Electrochemical Society 156 B252-B257. 

For ion thruster hollow cathode, degradation model has the following two basic hypotheses ... 

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