Ethylenediamine-Assisted High Yield Exfoliation of MoS2 for Flexible Solid-State Supercapacitor Application

A high yield synthesis technique of few-layer MoS2 by ethylenediamine (EDA)-assisted liquid phase exfoliation is reported. In the cyclic two-step process, EDA is adsorbed initially followed by sonication with propylene carbonate. The combination of organic solvents results in the exfoliation of micrometer sized few-layer two-dimensional (2D) MoS2 nanosheets within a short duration. Controlled gradual centrifugations separate 2D MoS2 of different sizes ranging from nanocrystals to micrometer sized flakes. The method differs from other sonication-induced fragmentation processes and results in larger sized nanosheets up to similar to 2.0 mu m of lateral dimension having a thickness of similar to 2-3 nm with high yield. Optical properties of the 2D nanosheets are studied by UV-vis absorption and Raman spectroscopy. Finally, the exfoliated MoS2 is employed to fabricate flexible solid-state supercapacitors, which shows superior performance compared to bulk MoS2-based devices, indicating its potential for energy storage applications.