Theoretical investigation of the intercalation mechanism of VS2/MXene heterostructures as anode materials for metal-ion batteries

Abstract

Ti2CO2 is one of the lightest MXenes, which is beneficial for achieving higher capacity as electrode material for batteries. However, its semiconductor conductivity has a negative effect on its charging/discharging rate and cyclability performance as electrode materials for batteries. Integrating two different two-dimensional materials to form heterostructures is an effective strategy to optimize the properties of materials. In this work, two heterostructures VS2/Ti2CT2 (T = O and S) are constructed and their electrochemical performances as anode materials for Li, Na and Mg-ion batteries are explored based on first-principles calculations. First of all, the lattice mismatch of these two heterostructures are relatively small, particularly, the lattice mismatch of VS2/Ti2CS2 is as low as 0.63%. Besides, compared with common graphene/Ti2CO2 and MoS2/Ti2CO2 heterostructures, VS2/Ti2CT2 simultaneously exhibit superior metal conductivities and stronger adsorption properties towards Li, Na and Mg atoms, thus achieving higher capacities. Considering the strong adsorption properties, suitable diffusion energy barriers, low open circuit voltages and high capacities, VS2/Ti2CO2 and VS2/Ti2CS2 are proposed to be promising high-performance anode materials for Mg-ion batteries, and VS2/Ti2CS2 is a preferable anode material for Na-ion batteries.