Functionalized carbon nitride (g-CN) monolayer as a promising energy storage material: A density functional theory study

Two-dimensional graphitic carbon nitride (g-CN) sheet, functionalized with polylithiated molecules (CLi, OLi), has been investigated to study their structural, electronic and hydrogen (H) storage properties by van der Waals corrected first principles calculation. A strong binding of both CLi/OLi with two-sided coverage and large enough molecular distance ensures their uniform dispersion over the g-CN monolayer without forming clusters. Each Li in g-CN@2CLi (g-CN@2OLi) adsorbs 3H, due to its cationic nature through transferring a portion of its charge, resulting into a high H storage capacity of 10.34% (9.76%). The calculated H adsorption energies are well suited for practical applications.