A novel WS2/NbSe2 vdW heterostructure as an ultrafast charging and discharging anode material for lithium-ion batteries

Abstract

It is highly desirable to develop highly-efficient anode materials for rechargeable lithium-ion batteries, which not only require large storage capacities, but also high stabilities and superior electrical conductivities. In this work, the electronic structures, stabilities, and the Li adsorption preferences of lithiated WS₂ and NbSe₂ monolayers as well as a lithiated WS₂/NbSe₂ heterostructure were systematically investigated using first principles calculations. It was found that compared with the metallic NbSe₂ monolayer, the WS₂/NbSe₂ heterostructure appears to have a new state occupation where there was no state occupation in the sole NbSe₂ monolayer. The metallic character ensures good electrical conductivity for lithium-ion batteries. Additionally, the diffusion barrier of the WS₂/NbSe₂ heterostructure is lower than that of WS₂ and NbSe₂ monolayers. A lower diffusion barrier guarantees better charge and discharge performances of the WS₂/NbSe₂ heterostructure as a battery electrode. Most importantly, the heterostructure was predicted to have quite a high theoretical specific capacity. Our results manifest that the WS₂/NbSe₂ heterostructure is a promising anode material, and provide valuable insights into the exploration of a rich variety of two dimensional heterostructure materials for next-generation flexible energy storage and conversion devices.