Superlight Ambient Temperature Reversible Hydrogen Storage Media Based on Alkali and Alkali Earth Metal-Functionalized 2D Square-Octagon BCN Monolayer

Energy has always been the engine of human beings; however, because of the environmental pollution caused by traditional fossil fuels, the development of more sustainable energy resources is urgently needed. The hydrogen storage medium is essential for its realization. Here, we introduce a hydrogen storage material, a two-dimensional (2D) square-octagon BCN (SO-BCN) monolayer, composed of lightweight elements (B, C, and N) and strategically functionalized with alkali and alkali earth metal atoms (Li, Na, Mg, and K). Notably, Li@SO-BCN and Mg@SO-BCN exhibit exceptional reversible hydrogen storage capabilities, surpassing the DOE standard of 5.5 wt %, with gravimetric capacities of 7.129 wt % and an impressive value of 11.656 wt %, alongside low adsorption energies of -0.21 eV/H