Light metal decoration on nitrogen/sulfur codoped graphyne: An efficient strategy for designing hydrogen storage media

摘要

Nitrogen/sulfur dual doped carbon materials have attracted a great deal of interest due to their fascinating applications in lithium ion batteries, hydrogen storage, and oxygen reduction reactions. Here, the hydrogen storage capacity of NS dual-doped graphyne (GYNS) decorated with Li or Na is theoretically explored. The NS-codoping leads to greater charge transfer and stronger binding between the alkali metal and graphyne surface giving rise to enhanced hydrogen storage capacity. We showed that the NS-codoping increases the hydrogen storage capacities of Li-decorated and Na-decorated GY by almost 30% and 60%, respectively. At high NS concentration, the hydrogen uptake capacities can reach to 8.98 wt% and 9.34 wt% for double-side Li- decorated GYNS and Na-decorated GYNS. Moreover, the average adsorption energies per H-2 are -0.27 eV for 2Li/GYNS(33.3%) and -0.26 eV for 2Li/GYNS(33.3%) which lie in desirable range for practical applications at ambient conditions.