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

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.