Optical, mechanical and electrical properties of LSCF-SDC composite cathode prepared by sol-gel assisted rotary evaporation technique

La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) is a perovskite-type oxide that exhibits excellent mixed ionic-electronic conducting properties and is a suitable cathode material for intermediate temperature solid oxide fuel cells. This study investigates the microstructural, optical, mechanical, and electrical properties of an LSCF-samarium-doped ceria (SDC) composite cathode. LSCF-SDC composite cathode powders were prepared by mixing 50 wt% SDC electrolyte with LSCF cathode powders obtained by the rotary evaporation technique. The band gap of the prepared powders was determined via diffuse reflectance UV-visible spectroscopy. The chemical composition, mechanical properties, and electrochemical properties of the sintered pellets were characterized using Raman spectroscopy, Vickers hardness, and impedance spectroscopy, respectively. X-ray diffraction and Rietveld analysis showed that phase purity was only 96%. Moreover, a small fraction of tetragonal phase impurity was observed on the LSCF powders. Impurities significantly affected the phase stability and microstructure of the LSCF-SDC composite cathode. The addition of the SDC electrolyte enhanced the densification of the composite cathode, thereby improving mechanical properties. However, the addition of SDC exerted different effects on the DC electrical conductivity and area-specific resistance (ASR) of the composite cathode. At 800 A degrees C, the ASR value of the LSCF was only 2% that of the LSCF-SDC composite cathode. Overall, the electrical properties of the LSCF-SDC composite cathode are closely related to the crystal structure, purity, and microstructure of LSCF cathode powders. [GRAPHICS] .