2019 年 46 巻 1 号
Bulk single crystals of the solid state electrolyte and cathode materials in the lithium ion batteries are necessary to precious measurements of the electrochemical properties in the lithium ion batteries and development of all single-crystalline lithium ion battery. La2/3-xLi3xTiO3 (LLT) and LiCoO2 are expected as the candidates of solid state electrolyte and cathode in the all solid state batteries. In this paper, growth of the bulk single crystals of LLT and LiCoO2 by the traveling solvent floating zone (TSFZ) method are reported. Inclusion-free LLT single crystals of approximately 5 mm φ and 40 mm long were grown successfully using a LLT stoichiometric feeds and a 10 mol% La2Ti2O7-poor composition solvent relative to the stoichiometric LLT in a four-mirror type image furnace, since LLT melt incongruently to La2Ti2O7 and a liquid. Also high quality LiCoO2 single crystals of about 5 mm φ and 70 mm long were successfully in an ambient pressure of argon using a LiCoO2 stoichiometric feeds and a Li-excess solvent of an atomic ratio Li:Co=85:15 at a tilting angle 𝜃= 10° in a mirror-tilted FZ furnace.