Metallized siligraphene nanosheets (SiC7) as high capacity hydrogen storage materials

A planar honeycomb monolayer of siligraphene (SiC 7 ) could be a prospective medium for clean energy storage due to its light weight, and its remarkable mechanical and unique electronic properties. By employing van der Waals-induced first principles calculations based on density functional theory (DFT), we have explored the structural, electronic, and hydrogen (H 2 ) storage characteristics of SiC 7 sheets decorated with various light metals. The binding energies of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca),scandium (Sc), and titanium (Ti) dopants on a SiC 7 monolayer were studied at various doping concentrations, and found to be strong enough to counteract the metal clustering effect. We further verified the stabilities of the metallized SiC 7 sheets at room temperature using ab initio molecular dynamics (MD) simulations. Bader charge analysis revealed that upon adsorption, due to the difference in electronegativity, all the metal adatoms donated a fraction of their electronic charges to the SiC 7 sheet. Each partially charged metal center on the SiC 7 sheets could bind a maximum of 4 to 5 H 2 molecules. A high H 2 gravimetric density was achieved for several dopants at a doping concentration of 12.50%. The H 2 binding energies were found to fall within the ideal range of 0.2–0.6 eV. Based on these findings, we propose that metal-doped SiC 7 sheets can operate as efficient H 2 storage media under ambient conditions.