Hetero-structured composite cathodes by electrospinning with high CO₂ -poisoning tolerance for solid oxide fuel cells

The sluggish oxygen reduction reaction (ORR) kinetics significantly hinder the development of intermediate temperature solid oxide fuel cells (IT-SOFC). Herein, a heterostructure composite fibers cathode composed of Ba0.9La0.1Co0.7Fe0.2Nb0.1O3-delta and Sm0.2Ce0.8O2-delta (BLCFN-SDC fibers) has been co-synthesized by electrospinning method, which exhibited excellent electrochemical activity, CO2 tolerance and long-term stability. The polari- zation resistance (Rp) of BLCFN-SDC fibers cathode at 700 degrees C is only 0.050 omega cm2, much lower than those of single-phase BLCFN fibers (0.069 omega cm2) and BLCFN powders (0.073 omega cm2). Such improvement can be attributed to the extended three-phase boundary (TPB) and more exposed oxygen reduction reaction (ORR) active sites. Besides, the unique fibers structure provides continuous charge transport paths, which improve its conductivity. Furthermore, BLCFN-SDC fibers exhibits excellent CO2 tolerance in high concentration CO2 at- mosphere, benefited from the low CO2 adsorption characteristics and stability of SDC. The results suggest that such heterostructure fibers cathode with excellent ORR activity and CO2 durability might provide a novel method to design efficient catalysts for SOFCs and other energy conversion devices.