Superalkali NLi4 functionalized 2D-BeN4 as a promising hydrogen storage medium: An ab initio DFT and AIMD investigations

Using density functional theory and molecular dynamics calculations, an NLi₄ cluster-functionalized beryllium polynitride nanosheet has been developed as a novel system for hydrogen storage applications. On both sides of NLi₄ functionalization, the adsorption energy measures −3.33 eV, suggesting a strong attraction between the superalkali NLi₄ and BeN₄ monolayer. After hydrogen saturation, the 2NLi₄@BeN₄ system demonstrates the capability to adsorb 28 hydrogen molecules, achieving a hydrogen gravimetric capacity of 10.65 wt%, surpassing the regulatory targets set by the US-DoE. Molecular dynamics calculations reveal the reversibility of H₂ molecules, the structural and thermal stability of the H₂ molecule-saturated BeN₄ monolayer. Based on the Van't Hoff formula, studies on decomposition temperature indicate the potential for hydrogen molecule storage reversibility under ambient conditions. The minimal activation energy suggests that H₂ molecules can move swiftly on the NLi₄@BeN₄ materials during adsorption/desorption processes. The energetic properties and high hydrogen capacity of NLi₄-functionalized BeN₄ make it an ideal candidate for hydrogen storage applications.