Exfoliation of MoS 2 Nanosheets Enabled by a Redox-Potential-Matched Chemical Lithiation Reaction.

Ion intercalation assisted exfoliation is the oldest and most popular method for the scalable synthesis of molybdenum disulfide (MoS 2 ) 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 MoS 2 . 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 MoS 2 , thus allowing precise Li + intercalation to form a lamellar LiMoS 2 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.