Elucidating the influence of molten salt chemistries on the synthesis and stability of perovskites oxides

Abstract

In this work, we investigate the synthesis of (La_0.8Sr_0.2)MnO₃ (LSM) in various molten salts to gain insight on the influence of molten salt ions for synthesizing materials critical for energy applications. LSM nanoparticles with a size range of ∼10–200 nm and with target stoichiometries were formed from oxide precursors via feeding into KNO₃. Furthermore, feeding precursors into the melt compared to mixing and heating from room temperature results in complete formation of LSM that was otherwise unattainable using conventional molten salt synthesis methods. In LiCl–KCl eutectic, the high Lux acidity of Li⁺ and Cl⁻ establishes a thermodynamic barrier that impedes Sr from reacting with other precursors in solution and increases Sr stability in the melt compared to the perovskite phase. As a result, LSM will not form in a LiCl–KCl eutectic under ambient conditions. Thus, this study further explicates the molten salt synthesis for perovskites and can serve as a guide for future syntheses.