Reversible Hydrogen Storage in Metal-Decorated Honeycomb Borophene Oxide.

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