[20p-C212-1~7] Hydrogen in oxides and its role

[20p-C212-5] Fast hydride ion conduction in LaH_3–2xO_x at intermediate-temperature

〇Soshi Iimura¹, Keiga Fukui¹, Tomofumi Tada¹, Satoru Fujitsu¹, Masato Sasase¹, Hiromu Tamatsukuri², Takashi Honda², Kazutaka Ikeda², Toshiya Otomo², Hideo Hosono¹ (1.TiTech, 2.KEK)

Keywords:ionic conductor, hydride ion

Hydride (H⁻) ions are electrochemically attractive charge carriers not only because they have small ionic radii and a valence electron shell suitable to ionic conduction in solids but also because of the high standard redox potential of H₂/H⁻ (−2.3 V). In this study, we focus on LaH_3–2xO_x and examine the electric properties. The hydride ion conductivity at 340°C and x = 0.25, 0.50 exceeds 10⁻² Scm⁻¹, which is the highest value at intermediate temperature. The ion transport numbers at this condition are over 99.8%. In this presentation, we discuss the synthesis, structural analyses, and the mechanism of H⁻ conduction in detail.