B3C2N3 monolayer with vacancy defects decorated with lithium as a potential hydrogen storage system: a DFT study

Abstract

This research explores the capability of lithium-modified pristine and defect-engineered B₃C₂N₃ monolayers (V_B, V_C, and V_N) for hydrogen storage, employing periodic DFT calculations. Several key metrics were evaluated, including the adsorption and binding energies of lithium atoms and H₂ molecules on these substrates, storage capacity, desorption temperatures, electronic characteristics, and the molecular stability of the structures. The findings reveal that the most thermodynamically favorable configuration comprises eight lithium atoms, yielding an optimal adsorption energy of −0.199 eV per H₂ molecule in the final state, designated as 20H₂@8Li-V_C. This configuration further exhibits a gravimetric hydrogen storage capacity of 8.4 wt% and enables hydrogen desorption at approximately 256 K. The investigation of the dynamic and thermal characteristics of the 8Li-V_C system, conducted through ab initio molecular dynamics simulations, provides valuable insights and guidance for future efforts aimed at utilizing this monolayer in hydrogen storage applications with the 8Li-V_C arrangement.