A DFT Study of Halogen (F-, Cl-, and Br-) Encapsulated Ga12X12 (X = N, P, and As) Nanocages for Sodium-Ion Batteries

In this work, we have theoretically investigated the adsorption of Na and Na+ ions on Ga12N12, Ga12P12, and Ga12As12 nanocages as anode materials for sodium-ion batteries (SIBs) using density functional theory (DFT). The geometrical parameters, interaction energy (E-int), frontier molecular orbitals (FMOs), and electrochemical properties of neutral and cationic Na with the nanocages were comprehensively examined. Based on the results, the structural parameter reveals that the Na atom binds strongly to N, P, and As atoms of the nanocages. Among the complexes, the smallest bond distance of 2.206 A is noted for Na/Ga12N12 nanocage. Additionally, higher interaction energy of - 57.99 kcal/mol is observed for Na+/Ga12N12 and the FMOs analysis illustrates that Na+ has more significant interaction than the neutral one. Furthermore, encapsulating the complexes with halide (F-, Cl- and Br-) results in higher cell voltage (V-cell) on comparison with the bare nanocage of SIBs. The overall analysis illustrates that fluorine encapsulated Na/Ga12N12 has more V-cell than chlorine and bromine.