Monolayer MoS₂ Fabricated by In Situ Construction of Interlayer Electrostatic Repulsion Enables Ultrafast Ion Transport in Lithium-Ion Batteries

Highlights: In-situ construction of electrostatic repulsion between MoS₂ interlayers is first proposed to successfully prepare Co-doped monolayer MoS₂ under high vapor pressure.The doped Co atoms radically decrease bandgap and lithium ion diffusion energy barrier of monolayer MoS₂ and can be transformed into ultrasmall Co nanoparticles (~2 nm) to induce strong surface-capacitance effect during conversion reaction.The Co doped monolayer MoS₂ shows ultrafast ion transport capability along with ultrahigh capacity and outstanding cycling stability as lithium-ion-battery anodes. Abstract: High theoretical capacity and unique layered structures make MoS₂ a promising lithium-ion battery anode material. However, the anisotropic ion transport in layered structures and the poor intrinsic conductivity of MoS₂ lead to unacceptable ion transport capability. Here, we propose in-situ construction of interlayer electrostatic repulsion caused by Co²+ substituting Mo⁴⁺ between MoS₂ layers, which can break the limitation of interlayer van der Waals forces to fabricate monolayer MoS₂, thus establishing isotropic ion transport paths. Simultaneously, the doped Co atoms change the electronic structure of monolayer MoS₂, thus improving its intrinsic conductivity. Importantly, the doped Co atoms can be converted into Co nanoparticles to create a space charge region to accelerate ion transport. Hence, the Co-doped monolayer MoS₂ shows ultrafast lithium ion transport capability in half/full cells. This work presents a novel route for the preparation of monolayer MoS₂ and demonstrates its potential for application in fast-charging lithium-ion batteries.[MediaObject not available: see fulltext.]