Performance of PrBaCo₂O_5+δ as a proton-conducting solid-oxide fuel cell cathode

The potential application of PrBaCo₂O₅-δ (PBC) double perovskite oxide as a cathode for a proton-conducting solid-oxide fuel cell based on a BaZr_0.1Ce_0.7Y_0.2O _3-δ(BZCY) electrolyte was systematically investigated. XRD and O₂-TPD results demonstrated that cation exchange between BZCY and PBC perovskites simultaneously occurs from the formation of Co³⁺-doped BZCY and Y³⁺-doped PBC. This event does not significantly change the cathodic polarization resistance. Under real fuel cell conditions, neither the electrolyte nor electrode resistances were significantly affected by the phase reaction and morphologic change of PBC. Anode-supported cells with an electrolyte thickness of ∼30 μm were successfully fabricated via a dual dry pressing process. Relatively high performance of 520 and 407 mW cm ^-2 at 700 °C was achieved for the cell with a PBC cathode fired at 950 and 1100 °C, respectively. A low electrode polarization resistance of 0.06 cm² was achieved at 700 °C for the PBC cathode calcined at 950 °C.