VO2/SnO2 superlattice enables metal-insulator alternating and Li migration barrier modulating

The VO2/SnO2 heterojunctions with adjustable electrical properties are considered to be of potential applications in micro-electronics. In this paper, the VO2/SnO2 superlattice model was constructed by stacking rutile VO2 and SnO2 along the c-axis direction, and first-principles calculations were conducted to reveal the electrical properties and Li migration properties of the VO2/SnO2 superlattices. Results show that the metal and semiconductor appear alternately in the VO2/SnO2 superlattice with the increasing number of VO2 layers. When the number of VO2 layers is odd (1, 3 or 5), the VO2/SnO2 superlattice presents a metallic state, the electronic conductivity increases and the Li migration energy barrier decrease with the increasing number of VO2 layers. When the number of VO2 layers is even (2, 4 or 6), the VO2/SnO2 superlattice displays a semiconducting state, and the electronic conductivity and Li migration energy show slight changes. The high electronic conductivity and controllable Li migration barrier in the VO2/SnO2 superlattices provide a reference for the application of VO2/SnO2 in Li-ion-based devices.