@inproceedings{oai:repo.lib.tut.ac.jp:00001351,
 author = {Inada, Ryoji and Kusakabe, Koji and Tanaka, Takayuki and Kudo, Shota and Sakurai, Yoji and 稲田, 亮史 and 日下部, 晃司 and 田中, 貴之 and 工藤, 翔太 and 櫻井, 庸司},
 book = {Solid State Ionics (Special issue Solid State Ionics 19 Proceedings of the 19th International Conference on Solid State Ionics. (SSI-19))},
 month = {Sep},
 note = {We investigated the properties of Al-free garnet related Li7La3Zr2O12 (LLZ) and Li7-xLa3Zr2-xTaxO12 (LLZTa) with Ta content x = 0.25, 0.5 and 1.0 synthesized by a solid state reaction method. It was confirmed that all Al-free LLZTa have the cubic garnet related structure, while Al-free LLZ without Ta substitution has tetragonal one. No other secondary phases were observed in all sintered samples. This indicates that partial substitution of Zr4+ by Ta5+ with higher valence increases Li-ion vacancy concentration in a garnet framework and stabilizes cubic garnet structure. The LLZTa grains are in good contact with each other although a certain amount of pores in the boundary area can be observed. Total (bulk + grain boundary) Li-ion conductivity at 27°C for all Al-free LLZTa were well above 10-4 Scm-1, while Al-free LLZ showed much lower room temperature conductivity of 1 × 10-5 Scm-1. The highest room temperature conductivity of 6.1 × 10-4 Scm-1 was obtained in Al-free LLZTa with x = 0.5, which is approximately 30−40% lower than the value in LLZTa (x = 0.5) with Al inclusion as previously reported.},
 pages = {568--572},
 publisher = {Elsevier},
 title = {Synthesis and properties of Al-free Li7-xLa3Zr2-xTaxO12 garnet related oxides},
 volume = {262},
 year = {2014}
}