Ambient Pressure Synthesis and H⁻ Conductivity of LaSrLiH₂O₂

摘要: Recently, hydride ion (H−) has come to be recognized as new charge carrier for the transport of hydrogen in solids by realization of pure H− conduction in BaH 2 and La 2− x− y Sr x+ y LiH 1− x+ y O 3− y oxyhydride system (LSLHO). In this study, the H− conductive oxyhydride, LaSrLiH 2 O 2 (x= 0, y= 1 in LSLHO), was synthesized by a conventional solid-state reaction at ambient pressure. The crystal structure of LaSrLiH 2 O 2, as well as the H− conductivity and bonding state of hydrogen, was examined by Rietveld analysis using X-ray and neutron diffraction data, attenuated total reflection Fourier transform spectroscopy (ATR-FTIR), and electrochemical impedance spectroscopy (EIS). The sample synthesized at ambient pressure had a K 2 NiF 4-type layered perovskite structure composed of alternately stacked tetragonal (LiH 2)− and (LaSrO 2)+ layers, and exhibited a conductivity of H− of 3.2× 10− 6 S cm− 1 at 300 C, which were the same structure and property as that reported previously for a sample synthesized by high-pressure synthesis.