Ion intercalation assisted exfoliation is the oldest and most popular method for the scalable synthesis of molybdenum disulfide (MoS2) nanosheets. The commonly used organolithium reagents for Li+ intercalation are n-butyllithium (n-BuLi) and naphthalenide lithium (Nap-Li); however, the highly pyrophoric nature of n-BuLi and the overly reducing power of Nap-Li hinder their extensive application. Here, a novel organolithium reagent, pyrene lithium (Py-Li), which has intrinsic safe properties and a well-matched redox potential, is reported for the intercalation and exfoliation of MoS2. The redox potential of Py-Li (0.86 V vs Li+/Li) is located just between the intercalation (1.13 V) and decomposition (0.55 V) potentials of bulk MoS2, thus allowing precise Li+ intercalation to form a lamellar LiMoS2 compound without undesirable structural damage. The lithiation reaction can be accomplished within 1 h at room temperature and the exfoliated nanosheets are almost single layer. This method also offers the advantages of low cost, high repeatability, and ease in realizing large-scale production.
Keywords: MoS2 nanosheets; chemical lithiation reaction; ion intercalation assisted exfoliation; polycyclic aryllithium compounds.