Ionic transport in SrCo0.85Ti0.15o3−δ ceramics at high oxygen pressures

Oxygen permeation through dense ceramic membranes of the SrCo0.85Ti0.15O3−δ cubic perovskite solid solution was studied in the range of the membrane feed-side oxygen partial pressures (p2) 0.21 to 100 atm at temperatures of 850–1040 K. The dependence of the oxygen fluxes on membrane thickness suggests that bulk ionic conductivity is the permeation-determining factor at high oxygen pressures (p2 > 1 atm). Increasing the oxygen pressure up to 80–100 atm was found to result in a drastic increase of the permeation flux, accompanied by a partial decomposition of the cubic perovskite phase of SrCo0.85Ti0.15O3−δ, forming two isostructural perovskite-type phases. No phase changes were observed after testing ceramics in the oxygen pressure range of 1–60 atm. The high oxygen permeation fluxes obtained demonstrate the applicability of SrCo0.85Ti0.15O3−δ membranes at high oxygen pressures.