Reversible Hydrogen Storage in Metal-Decorated Honeycomb Borophene Oxide

Abstract

Two-dimensional (2D) boron-based materials are receiving much attention as H2storage media due to the low atomic mass of boron and the stability of decorating alkali metals on the surface, which enhance interactions with H2. This work investigates the suitability of Li, Na, and K decorations on 2D honeycomb borophene oxide (B2O) for H2storage, using dispersion corrected density functional theory (DFT-D2). A high theoretical gravimetric density of 8.3 wt % H2is achieved for the Li-decorated B2O structure. At saturation, each Li binds to two H2with an average binding energy of −0.24 eV/H2. Born-Oppenheimer molecular dynamics simulations at temperatures of 100, 300, and 500 K demonstrate the stability of the Li-decorated structure and the H2desorption behavior at different temperatures. Our findings indicate that Li-decorated 2D B2O is a promising material for reversible H2storage and recommend experimental investigation of 2D B2O as a potential H2storage medium.