First-principles investigation of V2CSe2 MXene as a potential anode material for non-lithium metal ion batteries

The electrochemical performances of the V₂CSe₂ MXene as anode materials for Na, K, Mg, Ca, and Al-ion batteries have been systematically investigated by the first-principles method. The adsorption energies of metal atoms show that Na, K, and Ca atoms can effectively adsorb on the V₂CSe₂, except for Mg and Al atoms. The large diffusion constants for Na, K, and Ca atoms calculated by the diffusion energy barriers (0.098 eV for Na, 0.066 eV for Ca, and 0.24 eV for Ca) indicate the high mobility on the V₂CSe₂ surface. Significantly, the maximum theoretical capacities of V₂CSe₂ reach up to 394.12 mA h/g for Na and Ca ions. Furthermore, the low average open-circuit voltage (OCV) (0.150 V for Na, 0.175 V for K, and 0.072 V for Ca) indicates the V₂CSe₂ is a suitable anode material. These results provide fundamental guidance for the V₂CSe₂ monolayer as anode materials of non-lithium metal-ion batteries.