Effect of sintering temperature on perovskite-based hollow fiber as a substrate for cathode-supported micro-tubular solid oxide fuel cell

Abstract

Phase inversion-based extrusion was employed in this study to fabricate porous cathode-supported micro-tubular solid oxide fuel cell (MT-SOFC). The fibers were developed from two different perovskite materials; lanthanum strontium manganate (LSM) and lanthanum strontium cobalt ferrite (LSCF), which mixed with yttria-stabilized zirconia (YSZ). The effect of high sintering temperature (1250–1450 °C) on both hollow fibers was examined. Both LSM/YSZ and LSCF/YSZ composites were composed of asymmetric structure that consists of sponge-like and finger-like voids. LSM/YSZ hollow fiber gave higher mechanical strength of 161 MPa with sufficient porosity of 22% compared to LSCF/YSZ which exhibited mechanical strength of 114 MPa at 1400 °C. Besides, the gas permeation for both composite cathode hollow fibers showed the same declining trends as the function of sintering temperature. Moreover, X-ray diffraction (XRD) result showed a formation of a resistive phase when the sintering temperature reached 1300 °C for LSCF/YSZ and destruction of cobalt phase occurred at 1400 °C. In contrary, LSM/YSZ showed a stable sign where only a small amount of pyrochlore phase was found. To sum, LSM/YSZ is more compatible and stable at high sintering temperature in term of its mechanical strength, gas permeability, desired crystal structure, and acceptable range of porosity.