Atomic-level understanding on progressive lithiation of few-layer MoS2 with surface vacancies

Abstract

Vacancy engineering is a powerful modification strategy to elevate the electrochemical performance of electrode materials. In this work, the impacts of various surface vacancies in few-layer molybdenum disulfide (MoS2) on Li adsorption/intercalation and diffusion at both MoS2 surface and interlayers are systematically investigated to advance the material performance using first-principles calculations. The results show that the surface vacancy in few-layer MoS2 is easier to form than internal ones, and surface single S vacancy (VS) is the most stable. All seven surface vacancies can promote Li adsorption and intercalation at MoS2 surface and interlayer, and have a much more beneficial role on Li surface adsorption than interlayer intercalation. Surface single Mo vacancy (VMo) can upgrade the diffusion rate of Li at the few-layer MoS2 surface and nearby interlayer, and VS has a neglected impact on the rate capability. VMo is found to be the most propitious vacancy type for Li binding and diffusion at the few-layer MoS2. This theoretical exploration can help the comprehension of the impact of vacancies on the Li adsorption, intercalation, and transportation at the surface and interlayers of the dichalcogenides as high-performance electrode materials for rechargeable batteries.