B.A. Ali, N.K. Allam
The American University in Cairo,
Keywords: MoS2, supercapacitor, charge storage mechanism, diffusion capacitance, electrical double layer capacitance
Summary:MoS2 is a 2D material that has been widely used in supercapacitor applications due to its layered structure that provides a large surface area and allows for high electric double layer charge storage. To enhance the cycling stability and capacitance of MoS2, it is usually mixed with carbon materials. However, the dependence of the charge storage mechanism on the structure of the carbon material is still unclear in literature. Herein, the effect of the structure of the carbon material on the charge storage mechanism in 2H flower-shaped MoS2 is investigated in details. Specifically, 2H MoS2 was mixed with wither 8 nm-diameter carbon nanotubes (CNTs) or graphene nanoflakes (GNFs) in different weight ratios. Also, a composite of MoS2, CNTs and GNFs (1:1:1) was also studied. The charge storage mechanism was found to depend on the structure and content of the carbon material. Insights into the possible storage mechanism(s) were discussed. The MoS2/CNTs/GNFs composite showed a predominant pseudocapacitive charge storage mechanism where the diffusion current was ~89 %, with 88.31 % of the resulted capacitance was due to Faradic processes.