Investigation of structural, electrical and electrochemical properties of La0.6Sr0.4Fe0.8Mn0.2O3-{\delta} as an intermediate temperature solid oxide fuel cell cathode

TL;DR

This study synthesizes La0.6Sr0.4Fe0.8Mn0.2O3 using Sol-gel, evaluates its properties as an IT-SOFC cathode, and reports promising electrical and electrochemical performance metrics at intermediate temperatures.

Contribution

It introduces a new La0.6Sr0.4Fe0.8Mn0.2O3-based cathode material with detailed structural, electrical, and electrochemical characterization for IT-SOFC applications.

Findings

Maximum electrical conductivity of 35.35 S/cm at 783°C

Oxygen diffusion coefficients increased to 7.66*10^-6 cm^2/s

Area-specific resistances decreased to 0.31 Ω·cm^2 at 800°C

Abstract

La0.6Sr0.4Fe0.8Mn0.2O3 (LSFM) compound is synthesized by Sol-gel method and evaluated as a cathode material for the intermediate temperature solid oxide fuel cell (IT-SOFC). X-ray diffraction (XRD) indicates that the LSFM has a Rhombohedral structure with R-3c space group symmetry. The XRD patterns reveal very small amount of impurity phase in the LSFM and Y2O3-Stabilized ZrO2 (YSZ) mixture powders sintered at 600, 700 and 800 C for a week. The maximum electrical conductivity of LSFM is about 35.35 S.cm-1 at 783 C in the air. The oxygen chemical diffusion coefficients, DChem, are increased from 1.39*10-6 up to 7.66*10-6 .cm2. Besides, the oxygen surface exchange coefficients, kChem, are obtained to lie between 2.9*10-3 and 8.7*10-3 cm.s-1 in a temperature range of 600-800 C. The area-specific resistances (ASRs) of the LSFM symmetrical cell are 7.53, 1.53, 1.13, 0.46 and 0.31 .cm2 at 600, 650, 700, 750 and 800 C respectively, and related activation energy, Ea, is about 1.23 eV.