Dual-layer hollow fiber MT-SOFC using lithium doped CGO electrolyte fabricated via phase-inversion technique

Abstract

Anode-supported micro-tubular solid oxide fuel cell (MT-SOFC) made from lithium (Li) doped cerium gadolinium oxide (CGO) electrolyte was prepared via phase inversion based co-extrusion/co-sintering technique. In this study, the co-sintering temperature of CGO electrolyte with anode layer was reduced by adding Li that acts as sintering additive. The prepared Li doped CGO (Li-CGO) were characterized by shrinkage analysis, atomic resolution analytical microscope (ARM) observation and X-ray photoelectron spectroscopy (XPS) spectra. Meanwhile, the developed half-cell of MT-SOFC which was co-sintered at 1350–1500°C with interval of 50°C were characterized by its mechanical strength, gas tightness and microstructural analysis. The electrochemical performances of the cells were tested in anode-supported MT-SOFCs with configuration of Ni-CGO anode, Li-CGO electrolyte and LSCF-CGO cathode using humidified hydrogen as fuel and oxygen air as oxidant. MT-SOFCs fabricated with Li-CGO electrolyte were found to exhibit maximum power density of 60Wm−2 at 500°C compared to 200Wm−2 for cells with unmodified CGO electrolyte. The poor performance of cell with Li-CGO electrolyte is probably due to the combined effects of (i) moderately dense electrolyte layer and (ii) appearance of electronic conductivity in Li-CGO electrolyte. Nevertheless, lowering the sintering temperature has shown good properties of the electrolyte materials, which allows the electrolyte materials and anode can be co-sintered together at lower temperature.