Direct Salt Precursor Mechanochemical Synthesis forLa_1–<i>x</i>Sr_<i>x</i>Ti_1–<i>y</i>Mn_<i>y</i>O_3±δ Perovskite Nanomaterials as SolidOxide Oxygen Electrodes

Implementation of mechanochemical activation on the solid-state synthesis of perovskite metal oxides from salt precursors has been investigated for the preparation of La_1–<i>x</i>Sr_<i>x</i>Ti_1–<i>y</i>Mn_<i>y</i>O_3±δ electroceramics. The morphology, crystal structure, conductivity, and high-temperature characteristics of the resulting powders have been studied. All compounds were obtained as pure phase perovskite nanomaterials, with distorted symmetry with regard to the elemental doping and annealing temperature. The pure perovskite phase was achieved after high temperature annealing solely in the cases where mechanochemical activation was implemented, while other synthetic procedures tested (sol–gel and conventional solid-state) produced mainly mixed metal oxides, indicating the potential of the solvent-free direct salt precursor mechanochemical synthesis proposed herein. The electrochemical behavior of pure-phase oxide perovskites as screen-printed electrodes on commercial YSZ electrolyte disks was observed with EIS and LSV at 850 °C under synthetic air flow, while electrical properties under hydrogen gas flow were observed for pelleted samples. Results reveal that the mechanochemically synthesized LSTO achieved comparable electrochemical behavior to the equivalent LSM, with 0.89 A·cm^–2 at 1.75 V under synthetic air flow, showcasing its potential as both oxygen and hydrogen electrodes toward symmetrical reversible SOCs.