Synthesis, structure, and electrical conductivity of Sr2LiH2N nitride hydride

Guangzhong Jiang,Naoki Matsui,Takeya Mezaki,Yoshitake Toda,Kota Suzuki,Masaaki Hirayama,Takashi Saito,Takashi Kamiyama,Ryoji Kanno

doi:10.1016/j.jssc.2022.123051

Guangzhong Jiang, Naoki Matsui + Show 7 more

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https://doi.org/10.1016/j.jssc.2022.123051

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Abstract

K2NiF4-type structures, which exhibit diverse anion arrangements, are a promising framework for hydride ion conductors. Here, we synthesized Sr2LiH2N (SLHN), a nitride hydride with K2NiF4-type structure, and investigated the relationship between its structure and hydride ion conductivity. A solid-state reaction at 650 °C in a hydrogen atmosphere yielded almost-single-phase tetragonal SLHN. Rietveld analysis revealed that hydride ions occupied the equatorial sites and the apical sites in the perovskite layer whereas the nitride ions preferentially occupied the apical sites. In addition, a substantial amount of the anion vacancies (∼21%) was observed at the apical sites. The electrical conductivity of Sr2LiH2N was 1.1 × 10−6 S cm−1 at 300 °C. The solid solutions of Sr2LiH2+xOxN1–x in which nitride ions were partially substituted by oxide and hydride ions were synthesized. The electrical conductivity of Sr2LiH2+xOxN1–x enhanced with increasing oxygen and hydrogen contents and reached the maximum value of 7.2 × 10−6 S cm−1 for x = 0.2.

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