Mixed Conductivity and Oxygen Permeability of Doped Pr[sub 2]NiO[sub 4]-Based Oxides

-based oxides were studied as a series of new mixed electronic and oxide-ionic conductors for oxygen permeation membrane. High electronic conductivity was observed for the system and the temperature dependence was of metal-like behavior, i.e., it decreased with elevating temperature. The oxygen permeability of -based oxides was much higher than that of La 2 NiO 4 -based oxides with the same -type structure. The effects of the Ni-site dopant were also studied and it was found that the oxygen permeation rate was improved by doping Cu and Mg. In particular, doping of Cu is most effective for enhancing the oxygen permeation rate from air to He, and the optimum concentration of Cu was found at 20%. The maximum permeability of at was attained using a thick membrane. Addition of the excess Cu to significantly enhanced the oxygen permeation rate, probably due to the remarkable grain growth assisted by the formation of some Cu-containing liquid phase, and the oxygen permeation rate reached to with the same conditions.