One-Step Solvothermal Synthesis of Perovskite-Type Li_3<i>x</i>La_{2/3–<i>x</i>}□_{1/3–2<i>x</i>}TiO₃ Nanomaterials

Due to its high ionic and low electronic conductivity, the cubic perovskite polymorph of Li3xLa2/3–x□1/3–2xTiO3 (c-LLTO) is considered a canonical solid electrolyte for battery applications. However, traditional solid-state synthetic protocols for this high-performing polymorph are multistep and require high-temperature sintering at temperatures over 1000 °C, which creates challenges of processing and precludes the synthesis of nanomaterials that could be integrated into multifunctional, multicomponent architectures. In this study, the synthesis of c-LLTO is reported through a one-step solvothermal method in the presence of a surfactant. With this solution method, not only is it possible to obtain nanocrystals but also to stabilize c-LLTO at much lower temperatures than in conventional solid-state syntheses. In addition, the modulation of solvent and surfactant identities alters the reaction times necessary to facilitate crystallization at multiple scales of domain size, which suggests that confinement does not play much of a role in the stabilization of the cubic phase. The changes in particle size and shape were found to impart large differences in the measured Li dynamics through NMR, effectively illustrating that employing a solvothermal synthetic method enables the tuning of chemical properties for a targeted application.