Synthesis, Structural, Electrical and Microchemistry Properties of Novel (LSCFM) LaxSr1-xCo1-y-zFeyMnzO3-{\delta} (x=0.4, 0.6, 0.8, y=0.4, 0.8 and z=0.1, 0.2) Perovskites for SOFC Applications

TL;DR

This study synthesizes and characterizes novel LSCFM perovskites with varying compositions, analyzing their structure, microstructure, and electrical properties to evaluate their suitability as SOFC cathodes.

Contribution

It introduces new LSCFM compositions synthesized at low temperatures, providing detailed structural and electrical characterization for SOFC applications.

Findings

Maximum grain size of ~0.63 μm observed.

Electrical conductivity up to 1.29×10^3 Ω·cm.

Low temperature sintering favors a two-phase system with high conductivity.

Abstract

Perovskites are mixed oxides with the general formula ABO3. Many different compositions have been found to be possible and their number is growing rapidly due to their characteristics that make them ideal for various applications, such as fabrication of cathodes for solid oxide fuel cells (SOFCs). Oxide powders of LaxSr1-xCo1-y-zFeyMnzO3-{\delta} (x=0.4, 0.6, 0.8, y=0.4, 0.8 and z=0.1, 0.2), named LSCFM, were prepared by mixing commercial powders. The powders have been investigated as a function of the stoichiometry and the crystal structure parameters have been determined using Rietveld analysis. The results of the structural analysis for each sintered sample, at low temperature sintering (1100 {\omicron}C), have been obtained by considering two cubic perovskite phases, for x=0.4 or one cubic and one orthorhombic phase for x=0.6, 0.8, respectively. Analysis of microstructure has shown a maximum grain size of ~0.63 {\mu}m. The annealed sample at 1100 {\omicron}C, an almost single phase specimen, exhibited an electrical conductivity of 1.29\times103 ({\Omega} \cdot cm)-1. The sintered sample at 1250 {\omicron}C has higher conductivity but sharper curve close to the maximum. We suggest that low temperature sintering reveal two phase system with broader curve maximum and high conductivity for future applications in SOFCs.