- Previous Article
- Next Article
- Table of Contents
Journal of Power Sources, Vol.196, No.21, 8909-8917, 2011
Design of experiment approach applied to reducing and oxidizing tolerance of anode supported solid oxide fuel cell. Part II: Electrical, electrochemical and microstructural characterization of tape-cast cells
One of the major limitations of the nickel (Ni) - yttria-stabilized zirconia (YSZ) anode support for solid oxide fuel cells (SOFC) is its low capability to withstand transients between reducing and oxidizing atmospheres ("RedOx" cycle), owing to the Ni-to-NiO volume expansion. This work presents results on different anode supports fabricated by tape casting. Three compositions are prepared, as the outcome of a preceding design of experiment approach. The NiO proportion is 40, 50 and 60 wt% of the anode composite. The anode support characteristics like shrinkage during sintering, in-situ conductivity at high temperature, electrochemical performance and tolerance against RedOx cycles have been measured. Performance up to 0.72 W cm(-2) (0.62 V. 800 degrees C) is recorded for the 60 wt% NiO sample on small cells. The open circuit voltage is maintained within +/- 5 mV after 10 full RedOx cycles at 800 degrees C and one at 850 degrees C. Performances tend to be stabilized after one or multiple RedOx cycles. The microstructural observations show round Ni particles after the first reduction; after a RedOx cycle, the Ni particles include micro-porosities that are stable under humidified reducing atmosphere for more than 300h. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:RedOx cycling;SOFC reoxidation;Solid oxide fuel cells;Ni-YSZ anode support;Cermet electrical conductivity;Degradation