Investigation of Thermal, Structural and Electrical Properties of LaMnO₃-Sigma

LaMnO₃ is one of the most intensively studied cathode materials for solid oxide fuel cell (SOFC). In the present study, LaMnO3-d, cathode materials were synthesized by combustion method. The properties of synthesized materials like thermal, structural, electrical and electrochemical were investigated. Thermogravimetric analysis (TGA/DTA) analysis confirms that the calcination temperature (1000°C) is the appropriate temperature for the preparation of the materials using La (NO₃)₃.6H₂O, MnSO₄.H₂O, Co (NO₃)₂.6H₂O, Fe (NO₃) ₃.9H₂O and C₆H₈O₇.H₂O precursors. The X-ray powder diffraction (XRD) results of the materials reveal the formation of the hexagonal structure with R3C space group Fd3m.The scanning electron microscope (SEM) characterization shows that the prepared samples have slightly porous structure with agglomerated particles. The energy dispersive spectroscopy (EDS) analysis is also confirms the presence of La, Mn and O elements in all synthesized materials. From the fourier transform infrared spectroscopy (FTIR) analysis, the most significant absorption bands located at 1629.8cm¹ and 589.9cm¹ wave numbers are identified. The room temperature conductivity of the sample is found to be 6.3×10⁻³ for LaMnO₃ cathode material. From the dielectric constant ε′ as a function of frequency observed that value of ε′ maximum at lower frequencies and it begins to drop and becomes constant at higher frequencies.