Prediction Of A Multi-Center Bonded Solid Boron Hydride for Hydrogen Storage

TL;DR

This paper proposes a novel layered solid boron hydride with potential for efficient hydrogen storage, highlighting its dynamical stability and the effects of electron doping on phonon modes to facilitate hydrogen release.

Contribution

It introduces a new boron hydride structure designed for hydrogen storage, analyzing its stability and phonon behavior under electron doping.

Findings

Structure is dynamically stable without soft phonon modes.

Electron doping softens hydrogen-related phonon modes.

Boron-related phonons are unaffected or hardened by doping.

Abstract

An ideal material for on-board hydrogen storage must release hydrogen at practical temperature and pressure and also regenerate efficiently under similarly gentle conditions. Therefore, thermodynamically, the hydride material must lie within a narrow range near the hydrogenation/dehydrogenation phase boundary. Materials involving only conventional bonding mechanisms are unlikely to meet these requirements. In contrast, materials containing certain frustrated bonding are designed to be on the verge of frustration-induced phase transition, and they may be better suited for hydrogen storage. Here we propose a novel layered solid boron hydride and show its potential for hydrogen storage. The absence of soft phonon modes confirms the dynamical stability of the structure. Charging the structure significantly softens hydrogen-related phonon modes. Boron-related phonons, in contrast, are either hardened or not significantly affected by electron doping. These results suggest that electrochemical charging may facilitate hydrogen release while the underlying boron network remains intact for subsequent rehydrogenation.