Transition metal dichalcogenides (MoS2, MoSe2, WS2 and WSe2) exfoliation technique has strong influence upon their capacitance

Transition metal dichacogenides (TMD) represent an important class of layered compounds which are gaining lately an enormous interest in electrochemistry. Exfoliation of TMD materials to obtain single to few layer sheets is generally obtained through the intercalation of organolithium compounds. Here we investigated and compared the capacitive behavior of four representative TMD materials, i.e. MoS2, MoSe2, WS2 and WSe2 exfoliated with different organolithium intercalators, such as methyllithium (Me-Li), n-butyllithium (n-Bu-Li) and tert-butyllithium (t-Bu-Li). We found that both the metal/chalcogen composition and the type of intercalator strongly affect the capacitance of the exfoliated materials. These findings shall have profound implications on the construction of high-performance energy storage devices based on TMD. (C) 2015 Elsevier B.V. All rights reserved.