High-yield production of mono- or few-layer transition metal dichalcogenide nanosheets by an electrochemical lithium ion intercalation-based exfoliation method

Transition metal dichalcogenide (TMD) nanomaterials, especially the mono- or few-layer ones, have received extensive research interest owing to their versatile properties, ranging from true metals (e.g., NbS₂ and VSe₂) and semimetals (e.g., WTe₂ and TiSe₂) to semiconductors (e.g., MoS₂ and We₂) and insulators (e.g., HfS₂). Therefore, the reliable production of these nanomaterials with atomically thin thickness and laterally uniform dimension is essential for their promising applications in transistors, photodetectors, electroluminescent devices, catalysis, energy conversion, environment remediation, biosensing, bioimaging, and so on. Recently, the electrochemical lithium ion intercalation-based exfoliation method has emerged as a mature, efficient and promising strategy for the high-yield production of mono- or few-layer TMD nanosheets; monolayer MoS₂ (yield of 92%), monolayer TaS₂ (yield of 93%) and bilayer TiS₂ (yield of 93%) with lateral dimensions of ~1 µm (refs. ^1–3). This Protocol describes the details of experimental procedures for the high-yield synthesis of mono- or few-layer TMDs and other inorganic nanosheets such as MoS₂, WS₂, TiS₂, TaS₂, ZrS₂, graphene, h-BN, NbSe₂, WSe₂, Sb₂Se₃ and Bi₂Te₃ by using the electrochemical lithium ion intercalation-based exfoliation method, which involves the electrochemical intercalation of lithium ions into layered inorganic crystals and a mild sonication process. The whole protocol takes 26–38 h for the successful production of ultrathin inorganic nanosheets.