Characteristic fast H ion conduction in oxygen-substituted lanthanum hydride

Keiga Fukui, Soshi Iimura, Tomofumi Tada, Satoru Fujitsu, Masato Sasase, Hiromu Tamatsukuri, Takashi Honda, Kazutaka Ikeda, Toshiya Otomo, Hideo Hosono

Research output: Contribution to journalArticlepeer-review

65 Citations (Scopus)


Fast ionic conductors have considerable potential to enable technological development for energy storage and conversion. Hydride (H) ions are a unique species because of their natural abundance, light mass, and large polarizability. Herein, we investigate characteristic H conduction, i.e., fast ionic conduction controlled by a pre-exponential factor. Oxygen-doped LaH3 (LaH3−2xOx) has an optimum ionic conductivity of 2.6 × 10−2 S cm−1, which to the best of our knowledge is the highest H conductivity reported to date at intermediate temperatures. With increasing oxygen content, the relatively high activation energy remains unchanged, whereas the pre-exponential factor decreases dramatically. This extraordinarily large pre-exponential factor is explained by introducing temperature-dependent enthalpy, derived from H trapped by lanthanum ions bonded to oxygen ions. Consequently, light mass and large polarizability of H, and the framework comprising densely packed H in LaH32xOx are crucial factors that impose significant temperature dependence on the potential energy and implement characteristic fast H conduction.

Original languageEnglish
Article number2578
JournalNature communications
Issue number1
Publication statusPublished - Dec 1 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Biochemistry,Genetics and Molecular Biology
  • General Physics and Astronomy


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