The effect of calcium doping on the improvement of performance and durability in a layered perovskite cathode for intermediate-temperature solid oxide fuel cells

Abstract

Layered perovskite oxides have received extensive attention as promising cathode materials for solid oxide fuel cells (SOFCs) because of their faster diffusion coefficient and oxygen transport kinetics. With the goals of enhancing electrochemical properties and improving the durability, this study focuses on the effect of calcium (Ca) doping in PrBa 0.5 Sr 0.5Àx Ca x Co 2 O 5+d (x ¼ 0 and 0.25) layered perovskite oxides through an investigation of their structural characteristics, electrical properties, redox behavior, electrochemical performances, and stability. In the temperature range of 100-750 C, the electrical conductivity of PrBa 0.5 Sr 0.25 Ca 0.25 Co 2 O 5+d (PBSCaCO) is higher than that of Ca-free PrBa 0.5 Sr 0.5 Co 2 O 5+d (PBSCO). The area specific resistance (ASR) value of PBSCaCO-GDC (0.079 U cm 2 ) is lower than that of PBSCO-GDC (0.093 U cm 2 ) at 600 C, based on a GDC electrolyte. Moreover, PBSCaCO-GDC achieves a good performance of 1.83 W cm À2 at 600 C. PBSCaCO shows a stable power output without observable degradation for 100 h. On the basis of these results, the PBSCaCO cathode is an excellent candidate for IT-SOFC applications.

Perovskite as a Cathode Material: A Review of its Role in Solid‐Oxide Fuel Cell Technology

“…Lab‐scale long‐term performance tests should be accomplished on single cells before field tests (Figure ). The current density noticeably declines if any component or any condition of the cell is fragile (e.g., interface, hole, catalytic activity, sulfur, carbon), whereas that of a robust cell remains stable without any noticeable deterioration …”

A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

“…Intensive research has been carried out in an effort to explore cathode compositions suitable for operation at low temperature467101112131415. Oxides offering high mixed ionic and electronic conductivities (MIECs) are considered to be some of the most promising candidates for the next generation of SOFC cathodes due to their extended active sites for ORR when compared with purely electronic conducting materials1617.…”

Recent development on perovskite‐type cathode materials based on SrCoO3 − δ parent oxide for intermediate‐temperature solid oxide fuel cells

“…Therefore, suppressing such segregation should be effective alleviating the CO 2 poisoning of cathode. One way as proposed by Yildiz et al is to restrain the AE segregation by reducing the size mismatch between dopant and host, so that a much more stable single cell performance was achieved by replacing Sr with smaller‐size Ca into Pr (Ba, Sr)Co 2 O 5 + δ layered perovskite cathode at 550°C . The AE segregation may be also promoted by the oxygen defects .…”