Hydride-based antiperovskites with soft anionic sublattices as fast alkali ionic conductors

Most solid-state materials are composed of p-block anions, only in recent years the introduction of hydride anions (1s 2 ) in oxides (e.g., SrVO 2 H, BaTi(O,H) 3 ) has allowed the discovery of various interesting properties. Here we exploit the large polarizability of hydride anions (H – ) together...

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Bibliographic Details
Published in:Nature communications 2021-01, Vol.12 (1), p.201-10, Article 201
Main Authors: Gao, Shenghan, Broux, Thibault, Fujii, Susumu, Tassel, Cédric, Yamamoto, Kentaro, Xiao, Yao, Oikawa, Itaru, Takamura, Hitoshi, Ubukata, Hiroki, Watanabe, Yuki, Fujii, Kotaro, Yashima, Masatomo, Kuwabara, Akihide, Uchimoto, Yoshiharu, Kageyama, Hiroshi
Format: Article
Language:English
Subjects:
140/131
639/301/299/891
639/4077/4079/891
639/638/161/891
Anions
Chalcogenides
Conductivity
Conductors
Humanities and Social Sciences
Hydrides
Ion currents
Ions
Lattice vacancies
Lattice vibration
Lithium
Molten salt electrolytes
multidisciplinary
Phonons
Polarizability
Science
Science (multidisciplinary)
Sodium
Solid electrolytes
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Summary:Most solid-state materials are composed of p-block anions, only in recent years the introduction of hydride anions (1s 2 ) in oxides (e.g., SrVO 2 H, BaTi(O,H) 3 ) has allowed the discovery of various interesting properties. Here we exploit the large polarizability of hydride anions (H – ) together with chalcogenide (Ch 2– ) anions to construct a family of antiperovskites with soft anionic sublattices. The M 3 HCh antiperovskites (M = Li, Na) adopt the ideal cubic structure except orthorhombic Na 3 HS, despite the large variation in sizes of M and Ch. This unconventional robustness of cubic phase mainly originates from the large size-flexibility of the H – anion. 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 HM 6 octahedra in their cubic forms. Aliovalent substitution to create vacancies has further enhanced ionic conductivities of this series of antiperovskites, resulting in Na 2.9 H(Se 0.9 I 0.1 ) achieving a high conductivity of ~1 × 10 –4 S/cm (100 °C). Oxide-based lithium/sodium-rich antiperovskites are regarded as promising solid electrolytes. Here, authors report a series of antiperovskites with a soft lattice containing hydride (H – ) and chalcogenide (S 2– , Se 2– , Te 2– ) anions, enabling the fast Li + /Na + transport assisted by rotational phonon modes.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-020-20370-2