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Durability Study of SOFCs Under Cycling Current Load Conditions
Author(s) -
Hagen A.,
Hendriksen P. V.,
Frandsen H. L.,
Thydén K.,
Barfod R.
Publication year - 2009
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.200900013
Subject(s) - cycling , degradation (telecommunications) , anode , durability , materials science , constant current , current (fluid) , current density , electrical impedance , temperature cycling , composite material , computer science , electrical engineering , electrode , chemistry , telecommunications , physics , archaeology , quantum mechanics , history , engineering , thermal , meteorology
In fuel cell applications, the cells must be able to withstand varying operating conditions. Anode supported solid oxide fuel cells were tested under cycling current load in order to determine the durability and possibly identify degradation mechanisms. At 750 °C and a cycling between zero and 0.75 A cm –2 , the cell voltage degradation rate was similar to tests with the corresponding high constant current density. However, by analyzing the impedance spectra it was found that anode degradation was becoming more important when going from constant to cycling conditions. Running the cycling load tests at 850 °C, the cells degraded similarly as under the corresponding constant current load whereas, in some cases, cells failed mechanically after a few hundred hours. These cells did not experience severe additional degradation due to the cycling of the current density until the point of failure. The mechanical failure could be avoided if the cells were sealed to an interconnect rather than directly to an alumina test house. The degradation is discussed in the light of testing setup and conditions and cycling parameters. A mechanical analysis of the occurring problems is provided as well.