Sodium and magnesium ionic conduction in complex hydrides

Motoaki Matsuo, Hiroyuki Oguchi, Toyoto Sato, Hitoshi Takamura, Eiji Tsuchida, Tamio Ikeshoji, Shin Ichi Orimo

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58 Citations (Scopus)


Sodium and magnesium ionic conduction in complex hydrides as a new category of solid-state fast ionic conductors is presented. We first investigated experimentally the sodium ionic conductivities of the representative Na-based complex hydrides NaBH4, NaNH2, NaAlH4, and Na3AlH6, all of which have single complex anion [BH 4]-, [NH2]-, [AlH4] - and [AlH6]3-, respectively. Na 3AlH6 showed much higher ionic conductivity of 5 × 10-7 S/cm at 300 K than NaBH4, NaNH2, and NaAlH4 (their ionic conductivities were around 10-10 S/cm). We obtained the sodium fast-ionic conductor Na2(BH 4)(NH2) with the [BH4]- and [NH 2]- complex anions by combining NaBH4 and NaNH2 with a molar ratio of 1:1. It exhibited the most superior sodium ionic conductivity of 3 × 10-6 S/cm at 300 K because of the specific antiperovskite-type structure with vacancies in the Na+ site. Furthermore, first-principles molecular dynamics simulations suggested the possible magnesium ionic conduction in the high-temperature phase of Mg(BH 4)2 by substituting partly [BH4]- with [AlH4]-.

Original languageEnglish
Pages (from-to)S98-S101
JournalJournal of Alloys and Compounds
Issue numberSUPPL1
Publication statusPublished - 2013


  • Complex hydride
  • Magnesium ionic conduction
  • Sodium ionic conduction


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