Hydrogen storage capacity and reversibility of BC3N2 monolayers with and without Li decoration insights from first-principles methods

Abstract

The identification and development of novel materials for effective hydrogen storage is of paramount significance in the context of hydrogen-based economies. In this investigation, the hydrogen storage capabilities of the BC3N2 monolayer both with and without lithium (Li) decoration was examined by utilizing first-principles approaches. The findings indicate that the BC3N2 monolayer possesses a notable hydrogen storage capacity of 13.8 wt%. However, it is noteworthy that the average adsorption energy of H2 molecules is approximately 0.16 eV, resulting in a relatively low desorption temperature. This characteristic poses a significant obstacle to the practical utilization of the BC3N2 monolayer. Decoration of the BC3N2 monolayer with Li atoms was shown to be thermodynamically beneficial and resulted in non-aggregation on the surface. The monolayers of BC3N2 decorated with Li exhibited a remarkably high capacity for hydrogen adsorption, reaching 9.9 wt%. The ideal adsorption energies for this system were found to be in the range of 0.32–0.47 eV/H2. These results exceed the target set by the US DOE (6.5 wt%) and demonstrate superior performance compared to the majority of CN-based monolayers. The electrostatic properties of the interaction between H2 molecules and the monolayer decorated with Li were verified through the analysis of ELF and DOS. The reversibility of H2 molecule adsorption and desorption on Li-decorated BC3N2 monolayers has been demonstrated through the analysis of occupation number and desorption temperature under practical working conditions. The results of the study indicate that the incorporation of Li into BC3N2 monolayers has great potential as a highly efficient medium for hydrogen storage.