New bio-inspired design for high-performance and highly robust La0.6Sr0.4Co0.2Fe0.8O3-δ membranes for oxygen permeation

Ceramic-based oxygen permeation membranes (OPM) are considered to be promising for the separation of oxygen from air. However, state-of-art membrane designs are unable to deliver satisfactory performances in terms of permeation flux, mechanical/chemical stability and membrane surface area. In this study, a new bio-inspired design has been successfully introduced in the micro-monolithic membranes made of La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) for oxygen separation. By carefully controlling the process parameters of the fabrication and utilizing the hydraulic pressure of internal coagulant, the geometry of channels in the micro-monolith has been converted from a circular shape to a triangle shape with rounded corners. This new bio-inspired, 'orange-like' architecture not only reduces the effective oxygen diffusional length down to approximately 50 mu m, but also significantly increases the ratio of active region among the overall circumference up to 90%. This new bio-inspired micro-monolithic design displays an excellent oxygen permeation flux of 1.87 ml min(-1)cm(-2) at 950 degrees C, which is superior to the most reported values from LSCF material systems. In addition, such a design illustrates an excellent mechanical robustness that has long been a bottleneck for LSCF membranes. This work demonstrates a promising solution to tackle the long-existing trade-off between oxygen permeation performance and mechanical reliability.