Li decorated penta-silicene as a high capacity hydrogen storage material: A density functional theory study

The H2 adsorption characteristics of Li decorated single-sided and double-sided penta-silicene are predicted via density functional theory (DFT). The orbital hybridization results in Li atom strongly bind onto the surface of the penta-silicene with a large binding energy and it keeps the decorated Li atoms from aggregation. Moreover, Li decorated double-sided penta-silicene can store up to 12H2 molecules with the average hydrogen adsorption energy of −0.220 eV/H2 and hydrogen uptake capacity of 6.42 wt%, respectively. The ab initio molecular dynamics (AIMD) simulations demonstrate the H2 molecules are released gradually from the substrate material with the increasing simulation time and the calculated desorption temperature TD is 281 K in the suitable operating temperature range. Our explorations confirm that Li decorated penta-silicene can be regarded as a promising hydrogen storage candidate for hydrogen storage applications.