Enhanced hydrogen storage on Li-decorated χ 3-B: A first-principle study

High storage capacity and moderate adsorption strength are two important requirements for the successful development of hydrogen storage materials. In the present study, lithium atoms are dispersed above the hexagonal hollow sites of the chi 3-borophene 3-borophene (chi 3-B) 3-B) sheet with binding energies of-3.38 to-3.42 eV, leading to a high hydrogen storage capacity of 10.5 wt%. The generalized gradient approximation calculations show that the average adsorption energy is-0.22 eV/H2, 2 , which is in the scope of adsorption energy for hydrogen storage at room temperature. Each lithium atom transfers 0.83-0.86 e to the substrate and exists in the form of Li+ + cations, and the polarization electric field between the lithium and the boron atoms can polarize the hydrogen molecules moderately, thereby promoting hydrogen adsorption. Ab initio molecular dynamics (AIMD) simulation indicates that at ambient pressure and a temperature of 200 K, lithium modified chi 3-B 3-B can effectively capture hydrogen molecules without desorption. At a temperature of 300 K, 75 %-81 % of the hydrogen atoms are released from the adsorption system. The present study suggests that lithium decorated chi 3-B 3-B can be potential candidate for hydrogen storage at room temperature.