<scp> NLi ₄ </scp> ‐Functionalization of Arsenic Phosphorus Monolayer for Efficient Hydrogen Storage: Insights From a Theoretical Approach

ABSTRACT Two‐dimensional α‐phase arsenic phosphorus (2D α‐AsP) has attracted growing interest for energy storage applications owing to its high mechanical strength and favorable electronic properties compared with phosphorene. In this study, the hydrogen storage capability of α‐AsP is examined using first‐principles DFT and AIMD simulations, focusing on polarization‐driven interactions induced by NLi 4 superalkali clusters. NLi 4 binds strongly to 2D α‐AsP (binding energy −2.61 eV per NLi 4 ) owing to pronounced electron redistribution, which activates the surface toward H 2 physisorption. This charge transfer enables the (NLi 4 ) 2 @α‐AsP system to adsorb up to 44 H 2 molecules, achieving a gravimetric capacity of 6.15 wt.% and an average adsorption energy of −0.176 eV per H 2 at the PBE + vdW‐DF2 level, thereby exceeding the US DoE 2025 target of 5.5 wt.%. Thermodynamic analysis indicates that this capacity can be retained under near‐ambient conditions at 298 K and a hydrogen pressure of approximately 18.5 bar, suggesting the possibility of reversible storage under moderate operating pressures. Furthermore, hydrogen diffusion pathways exhibit low activation barriers, enabling rapid H 2 migration and efficient charge–discharge kinetics. AIMD simulations in the 100–300 K range indicate that the saturated 44H 2 /(NLi 4 ) 2 @α‐AsP system preserves excellent structural integrity under thermal fluctuations and displays significant H 2 release at 300 K on the simulated timescale. These results identify NLi 4 ‐functionalized α‐AsP as a promising candidate for solid‐state hydrogen storage and motivate future experimental studies on 2D As‐P‐based materials.