Oxygen absorption/desorption characteristics of Pb2CuSr2RCu2O8 + δ

Here we investigate the Pb2CuSr2RCu2O8 + δ (R = La, Nd, Eu, Y, Er, Yb and Lu) compounds as oxygen-storage (OS) materials. These materials can be reversibly charged and discharged with a large amount of oxygen up to δ ≈ 2.0 at low temperatures, but the drawback is that upon oxygen loading they decompose once the temperature exceeds ~ 600 °C. Fine-tuning of the OS characteristics is however achieved through the choice of the rare-earth constituent R. With increasing size of R, both the oxygen-storage capacity and the stability of the phase under oxygen-containing atmospheres are enhanced. Among the Pb2CuSr2RCu2O8 + δ compounds the most promising OS characteristics are found for R = La. These characteristics are discussed in comparison to those of two other layered oxide systems, YBaCo4O7 + δ and CuBa2YCu2O6 + δ.