An Investigation and Analysis of Structural and Electrochemical Properties of Highly Ionic La2-XSrXSn2O7-ẟ Electrolyte for SOFC Applications

This study primarily focused on the investigation, synthesis and analysis of lanthanum and tin pyrochlores electrolyte for solid oxide fuel cell (SOFC) applications. Ceramic samples with diverse compositions of La_2-xSr_xSn₂O_7-δ (x = 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3) were synthesized by using a solid-state reaction (SSR) methods. The prepared La_2-xSr_xSn₂O_7-δ samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) measurements. The findings were interpreted in terms of formation of high oxygen vacancy and structural disorder in the La_2-xSr_xSn₂O_7-δ matrix. The doping of lanthanum (La³⁺) by strontium (Sr²⁺) had a beneficial and remarkable effect on the structural and electrical properties: the increase in the rate of Sr²⁺decreased the lattice parameters of the crystalline phase and enhanced the creation of oxygen vacancies, which consequently increased the ionic conductivity and decreased the activation energy. Thus, it could be understood that the studied new La_2-xSr_xSn₂O_7-δ electrolyte would be one of the potential candidates for intermediate temperature SOFC applications.