;Operation of protonic ceramic fuel cell (PCFC) in the 500-800℃ range would enhance the durability of materials but also reduce the oxygen reduction reaction (ORR) rate at air electrode. The cathode material has high electronic/ionic mixed conductivity and has much greater electrocatalytic properties. Moreover, gas can easily diffuse to reduce the polarization loss in the solid oxide fuel cell (SOFC). In this study, we fabricate La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) nanofibers by electrospinning technique and then add silver slurry to form a complex material for protonic ceramic fuel cell (PCFC). Silver has a good catalytic activity, high electrical conductivity and is an inexpensive material, but silver particles can agglomerate easily at high temperature, which reduce the cathode porosity and result in poor PCFC performance. Therefore, we expect to improve the agglomeration of silver particles at high temperature by blending silver and LSCF nanofibers to form composite cathode. By analyzing cell performance (I-V curve) and electrochemical impedance spectroscopy (EIS), we can understand the reaction mechanism of gas, oxygen ions and electrons transport in the cathode. Secondly, by incorporating an interlayer into the interface between composite cathode and electrolyte can improves the electrolyte/cathode interfacial properties. It can effectively increase the density of triple phase points. The experimental results show that the 50wt%Ag–50wt%LSCF Fiber composite cathode has the best performance and shows the highest maximum power density of 445.37 mW/cm2 at 800℃, and the lower ohmic impedance and polarization impedance are 1.7370 Ω cm2 and 0.0683 Ω cm2, respectively. Besides, it only has a decay rate of 8% after 24 hours long-term stability test. From the results of this study, the LSCF nanofibers can effectively block the aggregation of silver particles, keep the cathode with good porosity, and reduce the polarization impedance. The 50wt%Ag-50wt%LSCF nanofiber composite cathode offers the potential for the future development of protonic ceramic fuel cell devices.
