# Atomic insights into the material properties of double-perovskite-type hydride LiNaMg2H6 for H2 storage applications

## TL;DR

This paper explores the hydrogen storage potential of the hydride LiNaMg2H6, showing it is stable and has high storage capacity.

## Contribution

The study provides atomic-level insights into the stability and hydrogen storage performance of LiNaMg2H6.

## Key findings

- LiNaMg2H6 is an insulator with a direct band gap of 2.8 eV and is dynamically and mechanically stable.
- The material has a gravimetric H2 storage capacity of 7.09 wt% and a volumetric capacity of 91.12 g L−1.
- The H2 desorption temperature is 548.54 K, aligning with experimental observations.

## Abstract

Perovskite-type compounds exhibit multi-functional properties that make them suitable for luminescence, photocatalysis, photovoltaics and H2 storage applications. Here, we provide atomic insights into the material properties of the double-perovskite-type hydride LiNaMg2H6 for H2 storage applications. Electronic structure calculations show that the cubic LiNaMg2H6 is an insulator with a direct band gap of 2.8 eV at the Γ point, consist with electron localization function and Born effective charge analyses. Based on geometric factors, elastic constants and self-consistent phonon calculations, we find that LiNaMg2H6 is dynamically and mechanically stable in the cubic phase at elevated temperatures, satisfying Born’s stability criteria. Finally, it is illustrated that the gravimetric and volumetric H2 storage capacities are 7.09 wt% and 91.12 g L−1, and the H2 desorption temperature is 548.54 K by considering the quantum effect, explaining well previous experimental observations. Our calculations highlight that LiNaMg2H6 hydride can be a potential H2 storage material because of its high H2 storage capacity, mechanical and dynamical stabilities and suitable H2 desorption temperature.

We systematically investigated the hydrogen storage properties of the double-perovskite-type hydride LiNaMg2H6, demonstrating the material’s stability, high storage capacities of 7.09 wt%, 91.12 g L−1, suitable dehydrogenation temperature of 540 K.