Supercapacitor characteristics of MoS2 and MoOx coated onto honeycomb-shaped carbon nanotubes

Abstract

Two-dimensional molybdenum disulfide (MoS2) with multilayer hierarchical structures is generally considered to be able to provide more active sites and shorter diffusion channels for electrolytes, which make them extremely suitable for supercapacitor applications. Nevertheless, the MoS2 poor conductivity and rare surface area are the major technical obstacles. Herein, we demonstrated a honeycomb basis using carbon nanotubes (CNTs). The honeycomb-shaped carbon skeleton provides a relatively larger surface area to store more ions with a more stable and stronger structure to maintain long-term electrochemical tests. During MoS2 fabrication, MoOx was also synthesized onto CNTs. MoOx influenced the electrochemical test results. Thermal annealing was conducted to remove the MoOx attachments to assure the optimal capacitance value. For the particular composite honeycomb structure (MoS2/CNTs) used in this research, the specific capacitance increased from 4.7 F/g (CNTs) to 75 F/g (MoS2 + MoOx/CNTs), measured using cyclic voltammetry measurements. The specific capacitance further reached 425 F/g using thermal annealing at optimal temperature, 700 °C. The designed electrode materials demonstrated excellent electrochemical characteristics and had great potential for future electrochemical applications.