TY - JOUR
T1 - Unique Growth Manner of Li5La3Ta2O12 Crystals from Lithium Hydroxide Flux at Low Temperature
AU - Xiao, Xiong
AU - Wagata, Hajime
AU - Hayashi, Fumitaka
AU - Onodera, Hitoshi
AU - Yubuta, Kunio
AU - Zettsu, Nobuyuki
AU - Oishi, Shuji
AU - Teshima, Katsuya
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/10/7
Y1 - 2015/10/7
N2 - Garnet-type Li5+xLn3MIV2-yMVyO12+z (x, y = 0-2, z = 0-1; Ln = La, Pr, Nd; M = Ta, Zr, Nb) compounds are promising Li-ion conducting solid electrolytes, but their growth manner is still unclear. Herein, the analysis of the low-temperature growth of idiomorphic Li5La3Ta2O12 single crystals as a function of holding temperature and time, cooling rate, flux type, and solute concentration revealed a unique growth manner. Li5La3Ta2O12 crystals were grown at 500 °C from LiOH flux and transformed into Li7La3Ta2O13 at 700 °C. The pseudo-perovskite-type LiLa2TaO6 phase, initially formed during the holding at 500 °C, was efficiently transformed into the Li5La3Ta2O12 phase with increasing holding time. The growth of Li5La3Ta2O12 single crystals was independent of the cooling rate but was affected by the kind of flux and solute concentration. A low solute concentration (1 or 5 mol %) was the key to obtain well-dispersed and idiomorphic single crystals. The optimum growth conditions involved a holding temperature of 500 °C, a solute concentration of 1 or 5 mol %, and a holding time of 10 h. These findings indicate that formation and growth of Li5La3Ta2O12 single crystals are not only controlled by a general flux growth process but also involve chemical reactions between solutes and LiOH flux. Finally, high-resolution transmission electron microscopy image and selected area diffraction pattern highlighted products with high crystallinity and well-developed {110} and {211} facets.
AB - Garnet-type Li5+xLn3MIV2-yMVyO12+z (x, y = 0-2, z = 0-1; Ln = La, Pr, Nd; M = Ta, Zr, Nb) compounds are promising Li-ion conducting solid electrolytes, but their growth manner is still unclear. Herein, the analysis of the low-temperature growth of idiomorphic Li5La3Ta2O12 single crystals as a function of holding temperature and time, cooling rate, flux type, and solute concentration revealed a unique growth manner. Li5La3Ta2O12 crystals were grown at 500 °C from LiOH flux and transformed into Li7La3Ta2O13 at 700 °C. The pseudo-perovskite-type LiLa2TaO6 phase, initially formed during the holding at 500 °C, was efficiently transformed into the Li5La3Ta2O12 phase with increasing holding time. The growth of Li5La3Ta2O12 single crystals was independent of the cooling rate but was affected by the kind of flux and solute concentration. A low solute concentration (1 or 5 mol %) was the key to obtain well-dispersed and idiomorphic single crystals. The optimum growth conditions involved a holding temperature of 500 °C, a solute concentration of 1 or 5 mol %, and a holding time of 10 h. These findings indicate that formation and growth of Li5La3Ta2O12 single crystals are not only controlled by a general flux growth process but also involve chemical reactions between solutes and LiOH flux. Finally, high-resolution transmission electron microscopy image and selected area diffraction pattern highlighted products with high crystallinity and well-developed {110} and {211} facets.
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U2 - 10.1021/acs.cgd.5b00672
DO - 10.1021/acs.cgd.5b00672
M3 - Article
AN - SCOPUS:84943514209
VL - 15
SP - 4863
EP - 4868
JO - Crystal Growth and Design
JF - Crystal Growth and Design
SN - 1528-7483
IS - 10
ER -