Pr0.6Sr0.4CoO3-δ (PSC) is an alternative material for widely used La0.6Sr0.4CoO3-δ with excellent activity as medium temperature SOFC cathode. However, so far there is lack of long-term test results for PSC. This study concentrates on the long term electrochemical characterization and microstructural post-test analysis of Ni-YSZ|YSZ|GDC|Pr0.6Sr0.4CoO3-δ 5 × 5 cm single cell, where YSZ is the yttria stabilized zirconia and GDC is the gadolinia doped ceria. Performance test conducted in SOFC mode at 650 °C and at cell potential 0.85 V was 17820 h long. Initial degradation of electrochemical performance was 2.6 % per 1000h. During second half of experiment degradation was only 1% per 1000h. Total power loss during test was 34.6 %. Moderate increase of total activation energy Etot at 0.8 V cell potential takes place (ΔEtot = 0.38 eV) and it increases from 0.57 eV to 0.95 eV. At 1V cell potential ΔEtot = 0.22eV, from 0.34 to 0.56 eV. Post mortem HR-SEM and TOF-SIMS analysis of tested cell has been performed and collected data show that minor structural changes caused by nickel coarsening in porous anode have been taken place. TOF-SIMS mappings of 5 × 5 cm electrode visualize the mobility of Sr from cathode into the electrolyte interface during electrode preparation. Some mobility of Si from gas-sealing glas to electrode as well as Cr deposition from Crofer 22APU current collector into electrode surface has been established.
[1] L. Blum, U. Packbier, I. C. Vinke, L.G. J. de Haart, Fuel Cells, 13 (4) 646-653