Fabrication of Y_2O_3-stabilized-ZrO_2(YSZ)/La_(0.8)Sr_(0.2)MnO_(3-α)-YSZ dual-layer hollow fibers for the cathode-supported micro-tubular solid oxide fuel cells by a co- spinning/co-sintering technique

摘要

Y_2O_3-stabilized-ZrO_2(YSZ)/La_(0.8)Sr_(0.2)MnO_(3-α) (LSM)-YSZ dual-layer hollow fibers have been fabricated for micro-tubular solid oxide fuel cells (MT-SOFCs) using a co-spinning/co-sintering technique. The hollow fibers consist of a dense YSZ top layer supported on the porous LSM-YSZ substrate with an asymmetric structure. The electrolyte and the cathode layers are perfectly adhered to each other without observable elemental inter-diffusion. Both the mechanical strength of the hollow fibers and the compactness of the electrolyte layer are improved by increasing the sintering temperature, whereas the effective porosity of the cathode layer also decreases. The suitable sintering temperature of the YSZ/LSM-YSZ dual-layer hollow fibers to construct the electrolyte/cathode half-cells should be controlled between 1350 ℃ and 1400 ℃. An Ni-YSZ layer of about 5 μrn in thickness is dip-coated on the outer surface of the hollow fibers to serve as the anode of fuel cells. The resultant micro-tubular SOFCs yield a maximum power density of 290 mW cm~(-2) at 850 ℃ using 1.49 × 10~(-5) mol s~(-1) hydrogen as fuel and 2.23 × 10~(-5) mol s~(-1) air as oxidant, respectively. The output performance of the micro-tubular fuel cells is mainly limited by the high polarization resistance of the cathode.