Performance of solid oxide fuel cells under fuel-side operational stresses

The performance of lab-scale solid oxide fuel cells (SOFCs) was evaluated under several types of non-ideal conditions affecting the anode (fuel electrode) including: inadequate exhaust of the combustion products; exposure to hydrogen-nitrogen fuel streams containing up to 500 ppm H₂S; interruption of the fuel stream; and leakage of air into the anode atmosphere. The cells were supported by yttria-stabilized zirconia (YSZ) electrolytes (3.8 cm diameter) and had lanthanum strontium manganite (LSM) cathodes and anodes of either Ni/YSZ or Ni/gadolinia-doped ceria (GDC). In addition, the anodes of some cells had been infiltrated with a 50- to 100-nm thick layer of nanocrystalline cerium oxide before testing. Cell performance was evaluated by monitoring output voltage and area-specific resistance (ASR) during galvanostatic operation. The non-ideal operating conditions produced distinctive changes in output voltage and ASR. These were attributed to microstructural changes in the anodes. The performance changes can potentially be used to diagnose, and possibly rectify, adverse operating conditions in the field.