TSFZ法による全固体リチウムイオン電池材料バルク単結晶の育成

抄録

  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. La_2/3-xLi_3xTiO₃ (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.