Ca3−xLaxCo4O9+δ (x=0, 0.3): New cobaltite materials as cathodes for proton conducting solid oxide fuel cell

Misfit-type Ca3−xLaxCo4O9+δ (x=0, 0.3) oxides were synthesised to be evaluated as possible cathode materials for proton conducting fuel cells (PCFCs) based on BaCe0.9Y0.1O3−δ (BCY10) dense ceramic electrolyte. The electrical conductivity value of Ca2.7La0.3Co4O9+δ (σ≈53 S cm–1 at 600 °C) is in the range of usually required value for a cathode application (about 50–100 S cm–1). In order to test the performance of each compound as cathode material, impedance measurements were carried out on Ca3−xLaxCo4O9+δ/BaCe0.9Y0.1O3−δ/Ca3−xLaxCo4O9+δ symmetrical half cells over the temperature range 400–800 °C under wet air. A promising electrocatalytic activity has been observed with both compounds Ca3Co4O9+δ and Ca2.7La0.3Co4O9+δ. Factually, the area specific resistance obtained was about 2.2 Ω cm2 at 600 °C.