Preparation and electrochemical properties of an La-doped Pr2Ni0.85Cu0.1Al0.05O4+δ cathode material for an IT-SOFC

Abstract

The cathode material Pr2-xLaxNi0.85Cu0.1Al0.05O4+δ (PLNCA, x = 0, 0.2, 0.5 and 1.0) was synthesized by an EDTA-citrate process for use in intermediate-temperature solid oxide fuel cells (IT-SOFCs). The phase structure and compatibility of the PLNCA with a La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte was characterized by X-ray diffraction analysis. A test of thermodynamic stability shows that only PrLaNi0.85Cu0.1Al0.05O4+δ can work for 72 h at 700 °C without decomposition. The average thermal expansion coefficient of the PLNCA material matches well with that of the LSGM electrolyte. The electrical conductivity of the PLNCA material varies in the range of 40–80 S cm−1 at 400 °C. The area specific resistance of the PLNCA cathode on LSGM electrolyte was determined to be 0.029, 0.035, 0.036 and 0.037 Ω cm2 for x = 0, 0.2, 0.5, 1.0 at 800 °C, respectively. Moreover, the power density of the electrolyte supported single cell for x = 0, 0.2, 0.5, 1.0 was determined to be 392, 357, 350 and 341 mW cm−2 at 700 °C, respectively. Among PLNCA materials, PrLaNi0.85Cu0.1Al0.05O4+δ shows the best compromise between electrochemical properties and thermodynamic stability and could serve as a potential cathode material for application in IT-SOFCs.