TY  - JOUR
AU  - Fang, Qingping
AU  - Frey, Carolin
AU  - Menzler, Norbert H.
AU  - Blum, Ludger
TI  - Electrochemical Performance and Preliminary Post-Mortem Analysis of a Solid Oxide Electrolyzer Stack with 20,000 h of Operation
JO  - Journal of the Electrochemical Society
VL  - 165
IS  - 2
SN  - 0013-4651
CY  - Pennington, NJ
PB  - Electrochemical Soc.
M1  - FZJ-2017-07703
SP  - F38 - F45
PY  - 2018
AB  - A long-term test with a two-layer solid oxide cell stack was carried out for more than 20,000 hours. The stack was mainly characterized in a furnace environment in electrolysis mode, with 50% humidification of H2 at 800°C. The endothermic operation was carried out with a current density of −0.5 Acm−2 and steam conversion rate of 50%. Electrolysis at lower temperatures (i.e., 700°C and 750°C) and fuel cell operation (with 0.5 Acm−2 and fuel utilization of 50%) at 800°C were also carried out (<2000 h each) for comparison. The voltage and area specific resistance degradation rates were ∼0.6%/kh and 8.2%/kh after ∼18,460 hours of operation. In total, the stack was operated above 700°C for more than 20,000 hours. Impedance measurement and analysis showed that the increase of ohmic resistance was the main degradation phenomenon, while electrode polarizations were kept nearly constant before a severe burning took place in one layer. Ni-depletion in fuel electrodes was confirmed during post-mortem analysis, which was assumed to be the major degradation mechanism observed. The stack performance and degradation analysis under different working conditions, as well as the results of preliminary post-mortem analysis will be presented.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000431786800104
DO  - DOI:10.1149/2.0541802jes
UR  - https://juser.fz-juelich.de/record/840144
ER  -