First-Principles Molecular Dynamics Simulations of Liquid Li$_{4}$BN$_{3}$H$_{10}$:Structural Characterization and Dynamics of Hydrogen Release

The recently discovered Li$_{4}$BN$_{3}$H$_{10}$ compound is a promising hydrogen storage material due to its high capacity for hydrogen desorption ($>$10 wt.\%) and favorable thermodynamics for low-temperature H$_2$ release. However, elevated temperatures are necessary for appreciable H$_2$ desorption, pointing to kinetic limitations. Further, Li$_{4}$BN$_{3}$H$_{10}$ is liquid at these H$_2$ release temperatures. In an effort to characterize the liquid structure and uncover the atomistic mechanisms for H$_2$ release, we have performed first-principles molecular dynamics simulations of liquid Li$_{4}$BN$_{3}$H$_{10}$. Our calculations give the temperature-dependent liquid structure, which we compare in detail with that of the crystalline solid. We are also able to ascertain the latent heat of melting, an important contribution to understanding the thermodynamics of H$_2$ release from this material. Finally, we present preliminary work on the atomistic mechanisms of hydrogen desorption from the liquid based on temperature accelerated molecular dynamics.