3, Ohio University, Athens, Oklahoma, United States
2, Ohio University, Athens, Ohio, United States
Monolayer molybdenum disulfide (MoS2) has been rigorously studied following the discovery of the first monolayer (or 2D) material, graphene, in 2004. The optical and electronic properties of monolayer MoS2 are of great interest, due to possible application in nano-scale devices such as transistors and photodetectors. In addition to these properties, monolayer MoS2 may possess the ability to contribute to pseudocapacitive redox reactions, when used as an electrode material in an electrochemical capacitor. Here, in order investigate its participation in faradaic charge transfer processes, we perform physical and electrochemical analysis of liquid-exfoliated few-layer MoS2 flakes in combination with carbon nanoparticles (a well-studied electric double-layer capacitor electrode material). Cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) curves of various concentrations of MoS2/C have already shown significant pseudocapacitive properties in the exfoliated MoS2. Reduction peaks are visible at +0.07 V and +0.20 V vs. Ag/AgCl in 0.05 M H2SO4, with corresponding oxidation peaks at +0.05 V and +0.18 V. With higher concentration of MoS2, these peaks become more prominent, supporting the hypothesis that MoS2 participates in faradaic charge transfer processes. Analysis of physical interactions between MoS2 nanoflakes and carbon nanoparticles have been investigated through scanning electron microscopy (SEM), transition electron microscopy (TEM), and energy-dispersive x-ray spectroscopy (EDXS).