Morphology control of the perovskite hollow fibre membranes for oxygen separation using different bore fluids

► Morphology of perovskite hollow fibres is controlled by using different bore fluids. ► LSCF hollow fibres with improved structure and oxygen fluxes have been fabricated. ► Asymmetric LSCF membranes with a dense skin layer are obtained in one single step. ► Maximum oxygen flux of the LSCF membrane can reach 34.4 mmol m−2 s−1 at 1000 °C. ► The effect of bore fluids on the hollow fibres' microstructure has been elucidated.