Computational exploration of graphyne and graphdiyne decorated with OLi3 as potential hydrogen storage candidates

Abstract

In this paper, we investigated the hydrogen storage capacity of OLi3 decorated graphyne and graphdiyne using density functional theory calculation. The optimization results showed that the OLi3 superalkalis were anchored strongly on the graphyne and graphdiyne with the adsorption energy of −3.82 and −4.04 eV, respectively. The binding energy between OLi3 and carbon nanosheet is much higher than that between two OLi3 superalkalis, indicating their uniform dispersion over the carbon material surface without any aggregation. The thermal stability has also been verified by ab inito molecular dynamics simulation. Decorating with OLi3 can effectively improve the hydrogen storage capacity of carbon monolayers. The hydrogen storage capacities of 4OLi3/GY and 8OLi3/GDY complexes are 7.23 and 8.87 w. t. %, with the average hydrogen adsorption energy of −0.252 and −0.218 eV per H2. The binding energy between Li and its neighboring H2 is contributed by the electron transfer and some orbital hybridization. The results suggest the complexes with reversible hydrogen storage properties at ambient temperature, indicating their potential use as promising hydrogen storage candidates.