Long-Term Degradation and Poisoning Effects of Ni-YSZ|YSZ|GDC|PSC in Electrolysis Mode

Abstract

This study provides long-term electrochemical test data of 5×5 cm Ni-YSZ|YSZ|GDC|PSC solid oxide cells in electrolysis mode. Pr0.6Sr0.4CoO3-δ (PSC) is an alternative material for widely used LSC with excellent activity as medium temperature oxygen electrode. The electrolysis was carried out at 800 °C at the cell voltage of 1.5 V. The duration of electrolysis test was 860 hours, at the end of which 18O2 was introduced to the oxygen electrode in the fuel cell mode. An average degradation rate was 16.3 % per 1000 hours of operation. After operation the membrane electrode assembly was analyzed using high resolution electron microscopy (HR-SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS) method. ToF-SIMS was used to conduct an oxygen isotope tracing experiment and to investigate distribution of strontium, silicon and chromium in the electrolyte, Ni-YSZ electrode and PSC electrode. HR-SEM was used to evaluate the changes in microstructure of the electrolysis cell.