Low-temperature growth of idiomorphic cubic-phase Li7La3Zr2O12 crystals using LiOH fluxElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ce00386e

Micrometer-sized Li 7 La 3 Zr 2 O 12 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 Li 7 La 3 Zr 2 O 12 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 Li 7 La 3 Zr 2 O 12 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 Li 7 La 3 Zr 2 O 12 crystal growth at 500 °C, beginning with La 2 Zr 2 O 7 powders that dissolve readily in hot LiOH. This will be examined in greater depth in the near future. Idiomorphic Li 7 La 3 Zr 2 O 12 crystals were grown from a LiOH flux at a low temperature of 700 °C. In addition, the use of La 2 Zr 2 O 7 powders as starting material resulted in further reduction of the reaction temperature to 500 °C.