Exploring N-rich phases in LixNy clusters for hydrogen storage at nano-scale

TL;DR

This study uses advanced computational methods to explore the stability and hydrogen storage potential of N-rich LixNy clusters at the nano-scale, revealing their promising properties for energy applications.

Contribution

It demonstrates that N-rich LixNy clusters are more stable than Li-rich phases in small sizes and highlights their potential for efficient hydrogen storage.

Findings

N-rich clusters are thermodynamically more stable than Li-rich phases in small sizes.

Hybrid xc-functional is essential for accurate stability predictions.

N-rich clusters enable easy hydrogen adsorption/desorption at low and moderate temperatures.

Abstract

We have performed cascade genetic algorithm and ab initio atomistic thermodynamics under the framework of first-principles density functional theory to study the (meta-)stability of a wide range of LixNy clusters. We found that hybrid xc-functional is essential to address this problem as a local/semi-local functional simply fails even to predict a qualitative prediction. Most importantly, we find that though in bulk Lithium Nitride, Li rich phase, i.e. Li3N, is the stable stoichiometry, in small LixNy clusters N-rich phases are more stable at thermodynamic equilibrium. We further show a that these N-rich clusters are promising hydrogen storage material because of their easy adsorption and desorption ability at respectively low (< 300K) and moderately high temperature (> 600K).