SOL-GEL SYNTHESIS AND PHASE PURITY OF SOLID ELECTROLYTES

摘要

La_(1-x)Sr_xGa_(1-y)Mg_yO_(3-δ) (LSGM) powders containing different amounts of Sr~(2+) and Mg~(2+) were prepared from precursors synthesised by either Pechini or citrate sol-gel method and by calcination at 1400 or 1500℃. All as-calcined powders contained small amounts of Sr- and Ga-containing phases (namely SrLaGa_3O_7 and SrLaGaO_4), as detected by X-Ray Diffraction (XRD). The relative amounts of these phases depended on both Sr and Mg levels and synthetic route. In particular, at a given Sr content (x), the relative amounts of SrLaGa_3O_7 and SrLaGaO_4 decreased with the increase of Mg, i.e. with the decrease of Ga content and, at a given Mg content (y), the amount of same Sr-containing phases increased with the Sr content. Finally, powders prepared by citrate method exhibited systematically higher phase purity than those obtained by Pechini process.