La_0.7Sr_0.3Fe_0.9Ni_0.1O_3−δ-Ce_0.8Sm_0.2O_2−δ Composite Cathode with a Hollow Nanofiber Structure Prepared through Coaxial Electrospinning for Protonic Ceramic Fuel Cells

Rational design of the electrode microstructure is an important strategy to improve the performance of solid oxide fuel cells. Electrospinning is an effective approach for the production of electrode materials with a nanofiber microstructure, which provides straight and continuous pathways for ionic and electronic conduction. In this study, the self-assembled La_0.7Sr_0.3Fe_0.9Ni_0.1O_3−δ (LSFN)-Ce_0.8Sm_0.2O_2−δ (SDC) composite with a hollow nanofiber structure is synthesized as the cathode material of protonic ceramic fuel cells (PCFCs) through a coaxial electrospinning process. LSFN and SDC are both distributed uniformly in the composite cathode. Compared with composite cathodes prepared through electrospinning with solid and core-shell nanofiber structures, the hollow-fiber LSFN-SDC cathode shows a higher specific surface area and provides more channels for gas diffusion, both of which are beneficial for the oxygen reduction reaction. The LSFN-SDC composite cathode with the hollow fiber structure exhibits the lowest polarization resistance of 0.035 Ω cm² at 700 °C. A PCFC with that cathode shows a maximum power density of 1598 mW cm^-2 and a promising short-term stability at 700 °C.