Low-temperature growth of idiomorphic cubic-phase Li7La3Zr2O12 crystals using LiOH flux

Abstract

Micrometer-sized Li₇La₃Zr₂O₁₂ crystals with well-developed facets were grown from a LiOH flux at 700 °C. Supersaturation-controlled crystallization driven by the cooling of a homogeneous hot solution with a Li/Zr ratio of 70 achieved one-step formation of cubic-phase Li₇La₃Zr₂O₁₂ that potentially exhibits high lithium-ion conductivity. Excess LiOH flux decreased the reaction temperature dramatically to 700 °C, lower than that of solid-state-reaction processes. The flux growth of the Li₇La₃Zr₂O₁₂ crystals in response to varying reaction conditions was studied systematically and indicated that the initial Li/Zr ratio and the holding temperature significantly affected the crystal phase, shape, and size. We further demonstrated Li₇La₃Zr₂O₁₂ crystal growth at 500 °C, beginning with La₂Zr₂O₇ powders that dissolve readily in hot LiOH. This will be examined in greater depth in the near future.