fig2

Figure 2. Sodium and potassium adsorption energetics, Diffusion Barrier, charge-transfer behavior, and the corresponding densities of states of V₂AB₄: (A) Geometric illustration of active energetic sites (a, b, and c), and (B) adsorption energies for Na⁺ and K⁺ ions on all four V₂AB₄-type monolayers; (C) CI-NEB energy profiles for V₂MoS₄, V₂MoSe₄, V₂WS₄, and V₂WSe₄; Visualization of (D) charge-density difference with corresponding Bader charge transfer from Na⁺ ions to V₂AB₄ surfaces (Yellow and cyan represent electron gain and electron loss, respectively, with the isosurface value of 0.002 e Å^-3); (E) Na⁺ induced projected density of states (PDOS) on V₂AB₄ monolayers. CI-NEB: Climbing-image nudged elastic band.