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

在我们最近发现了Ln=Sm，Gd，Tb，Dy，Ho和Er的LnHO之后，测量了氢化物(H-)的电导率。研究发现，尽管阴离子有序相(Ln=La，Nd)具有“化学计量”成分，但它仍具有氢化物导电性(例如，在300℃时，NdHO的电导率为2.3×10-S S cm-1)，而阴离子无序相(Ln=Gd，Er)是离子绝缘体。系统的结构分析和计算相结合揭示了间接间隙机制，H-离子通过由阴离子有序扩展的三角形Ln3瓶颈在四面体和八面体位置之间迁移，临界瓶颈半径为1.18A。此外，还开发了另一系列材料，通过利用氢化物阴离子(H-)的性质与硫族一起构建软阴离子-亚晶格，这是一个以前未被探索的反钙钛矿系列。尽管每个CH和M的尺寸变化很大，但M3HCh反钙钛矿(M=Li，Na；CH=硫族)采用了理想的立方结构(正交Na3HS除外)。与传统的钙钛矿不同，立方相的这种稳定性源于H-阴离子极大的尺寸灵活性/极化率。理论和实验研究表明，Li+/Na+的迁移势垒较低，离子电导率较高，这可能是由与HM6八面体在这种软立方晶格中的旋转运动有关的软声子模促进的。因此，氢化物基反钙钛矿材料为材料设计提供了新的探索方向。

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.