Hydrogen-enriched vanadium-sulfide-hydride Janus monolayer unlocks high-performance anodes for Li/Na/Ca-ion batteries

Janus two-dimensional (2D) materials are a unique class of materials with asymmetrically functionalized surfaces. This asymmetry can enable multifunctional applications in fields such as optoelectronics, energy storage, and catalysis. The present study explores the properties of hydrogen-enriched VSH Janus monolayer, derived from VS 2 transition metal dichalcogenide, as potential anode material for lithium-, sodium-, and calcium-ion batteries. Using first-principles calculations, we demonstrate that the semiconductor VSH Janus undergoes a transition to a metallic state upon interaction with a single metal ion, highlighting its promising electrochemical properties. Phonon dispersion and ab-initio molecular dynamics simulations confirm the dynamic and thermal stability of VSH. Additionally, our results show high net charge transfer rates and pronounced electron localization, indicative of strong ionic bonding in the Ca/Na/Li-VSH systems. Projected crystal orbital Hamiltonian population analysis reveals ionic interaction between metal ions and system elements, along with low diffusion energy barriers (<0.26 eV) and open circuit voltages (<0.43 V). Furthermore, VSH demonstrates high specific storage capacities of 4466.83 mAh g −1 , 638.11 mAh g −1 , and 850.82 mAh g −1 for Li + , Na + , and Ca 2+ ions, respectively. These findings indicate that the VSH Janus shows great potential as an anode material for Li + -, Na + -, and Ca 2+ -ion battery applications. • Hydrogen-enrichment on VS 2 to form the VSH TMDC Janus. • Lower voltage profile (< 0.25 V) found of Li + , Na + and Ca 2+ ions on VSH anode. • Fast ionic mobility via low diffusion energies (< 0.26 eV) of Li + /Na + /Ca +2 ion. • High storage capacities of Li, Na and Ca-ion (4466.83 mAh/g, 638.11 mAh/g and 850.82 mAh/g, respectively. • Reversible thermal stability of the fully loaded system at ambient temperature.