Electrochemical properties of GdBaCo2/3Fe2/3Cu2/3O5+δ–CGO composite cathodes for solid oxide fuel cell

Abstract The composite cathodes of double-perovskite structure of x wt.% Ce 0.9 Gd 0.1 O 1.95 (CGO)–(100 −  x )wt.% GdBaCo 2/3 Fe 2/3 Cu 2/3 O 5+ δ (FC-GBCO), where x  = 0, 10, 20, 40 and 50, were synthesized via a citrate combustion method followed by an organic precipitant method. The thermal-expansion coefficient (TEC) and electrochemical performance of the oxides were investigated as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The TEC exhibited by composite cathode made of 40 wt.% CGO–60 wt.% FC-GBCO (CG40) up to 900 °C is 13.7 × 10 −6  °C −1 , which is lower value than FC-GBCO (16.3 × 10 −6  °C −1 ). The composite cathode of CG40 coated on Ce 0.9 Gd 0.1 O 1.95 electrolyte showed the lowest area specific resistance (ASR) i.e., 0.041 Ω cm 2 at 750 °C. An electrolyte supported (300 μm thick) single-cell configuration of CG40/CGO/Ni-CGO attained a maximum power density of 800 mW cm −2 at 800 °C. The unique composite composition of CG40 exhibited enhanced electrochemical performance, reduced TEC and good chemical compatibility with CGO electrolyte compared with their FC-GBCO cathode for IT-SOFCs.