Superionicity in the hydrogen storage material Li2NH : Molecular dynamics simulations

• We have employed ab initio molecular dynamics simulations in an attempt to study a temperature-induced order-disorder structural phase transformation that occurs in Li2NH at about 385 K. A structural phase transition was observed by us in the temperature range 300-400 K, in good agreement with experiment. This transition is associated with a melting of the cation sublattice (Li+), giving rise to a superionic phase, which in turn is accompanied by an order-disorder transition of the N-H bond orientation. The results obtained here can contribute to a better understanding of the hydrogen storage reactions involving Li2NH and furthermore broaden its possible technological applications toward batteries and fuel cells.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

ab initio calculations

bonds (chemical)

hydrogen storage

lithium

compounds

molecular dynamics method

order-disorder transformations

augmented-wave method

crystal-structure

energy

diffraction

water

Physics

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