2019 Fiscal Year Annual Research Report
ＬｉとＮａバッテリーのための新規酸水素化物電極の合成と解析
| Project/Area Number |
17F17341
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| Research Institution | Kyoto University |
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Principal Investigator |
陰山 洋 京都大学, 工学研究科, 教授 (40302640)
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| Co-Investigator(Kenkyū-buntansha) |
BROUX THIBAULT 京都大学, 工学(系)研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2017-11-10 – 2020-03-31
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| Keywords | high pressure synthesis / oxyhydride |
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| Outline of Annual Research Achievements |
After our recent discover of LnHO with Ln = Sm, Gd, Tb, Dy, Ho, and Er, the hydride (H-) conductivity has been measured. It is found that, despite its “stoichiometric” composition, the anion-ordered phase (Ln = La, Nd) exhibits hydride conductivity (e.g., 2.3 × 10-S S cm-1 for NdHO at 300 °C), while the anion-disordered one (Ln = Gd, Er) is an ionic insulator. The systematic structural analysis combined with computational calculations has revealed the indirect interstitial mechanism, where H- anions migrate between the tetrahedral and octahedral sites through a triangular Ln3 bottleneck expanded by the anion order, with a critical bottleneck radius of 1.18 A. Besides that, another series of materials have been developed by exploiting hydride anions (H-) properties to construct a soft anion-sublattice together with chalcogens, in a previously unexplored antiperovskites series. Despite a large size variation for each Ch and M, the M3HCh antiperovskites (M = Li, Na; Ch = Chalcogen) adopt the ideal cubic structure (except orthorhombic Na3HS). Unlike traditional perovskites, such robustness of cubic phase originates from the extreme size-flexibility/polarizability of H-anions. Theoretical and experimental studies reveal low migration barriers for Li+/Na+ transport and high ionic conductivity, possibly promoted by a soft phonon mode associated with the rotational motion of HM6 octahedra in this soft cubic lattice. Hydride-based antiperovskites are thus offering a new direction for material design to explore.
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| Research Progress Status |
令和元年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和元年度が最終年度であるため、記入しない。
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