Eutectic Phenomenon of LiNH₂-KH Composite in MH-NH₃ Hydrogen Storage System

Kiyotaka Goshome; Ankur Jain; Hiroki Miyaoka; Hikaru Yamamoto; Yoshitsugu Kojima; Takayuki Ichikawa

doi:10.3390/molecules24071348

Eutectic Phenomenon of LiNH₂-KH Composite in MH-NH₃ Hydrogen Storage System

Molecules. 2019 Apr 5;24(7):1348. doi: 10.3390/molecules24071348.

Authors

Kiyotaka Goshome¹, Ankur Jain², Hiroki Miyaoka³, Hikaru Yamamoto⁴, Yoshitsugu Kojima^{5

6}, Takayuki Ichikawa^{7

8}

Affiliations

¹ Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology, 2-2-9 Machiikedai, Koriyama, Fukushima 963-0298, Japan. goshoume.kiyotaka@aist.go.jp.
² Natural Science Center for Basic Research and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan. ankur.j.ankur@gmail.com.
³ Natural Science Center for Basic Research and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan. miyaoka@h2.hiroshima-u.ac.jp.
⁴ Natural Science Center for Basic Research and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan. mhikaru@h2.hiroshima-u.ac.jp.
⁵ Natural Science Center for Basic Research and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan. kojimay@hiroshima-u.ac.jp.
⁶ Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan. kojimay@hiroshima-u.ac.jp.
⁷ Natural Science Center for Basic Research and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan. tichi@hiroshima-u.ac.jp.
⁸ Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan. tichi@hiroshima-u.ac.jp.

Abstract

Hydrogenation of a lithium-potassium (double-cation) amide (LiK(NH₂)₂), which is generated as a product by ammonolysis of litium hydride and potassium hydride (LiH-KH) composite, is investigated in details. As a result, lithium amide (LiNH₂) and KH are generated after hydrogenation at 160 °C as an intermediate. It is noteworthy that the mixture of LiH and KNH₂ has a much lower melting point than that of the individual melting points of LiNH₂ and KH, which is recognized as a eutectic phenomenon. The hydrogenation temperature of LiNH₂ in the mixture is found to be significantly lower than that of LiNH₂ itself. This improvement of reactivity must be due to kinetic modification, induced by the enhanced atomic mobility due to the eutectic interaction.

Keywords: ammonia; double-cation amide; eutectic melting; hydrogen carrier; metal hydride.

MeSH terms

Amides / chemistry*
Ammonia / chemistry
Hydrogen / chemistry*
Hydrogenation
Kinetics
Lithium / chemistry*
Potassium / chemistry*

Substances

Amides
Ammonia
Hydrogen
Lithium
Potassium