Incorporation of TiO2 nanoparticles in MoS2 nanosheets for electrochemical energy storage applications

Abstract

Recently, transition metal dichalcogenides (TMDCs) have gained attention as promising electrode materials for energy storage applications due to their exceptional physicochemical properties. Two-dimensional (2D) layered materials have demonstrated significant potential for electrochemical energy storage. Nevertheless, their performance is often hindered by slow kinetics and inadequate cycling stability. Modifying the interfaces of these 2D materials offers a viable strategy to increase active sites, enhance electronic conductivity, and improve structural stability, potentially addressing key challenges in the development of high-performance energy storage devices. In this study, we developed a rapid one-pot synthesis method for the MoS₂/TiO₂ binary composite. The resulting TiO₂ nanoparticles are integrated within the two-dimensional structure of agglomerated and wrinkled MoS₂ nanosheets. This arrangement enhances electrical properties and increases the surface area, making them suitable for electrodes in supercapacitors, facilitating electric double-layer and pseudocapacitance behaviors. The synthesized materials were utilized to construct both three and two-electrode configurations. In a three-electrode setup, the MoS₂ and MoS₂/TiO₂ composites exhibited specific capacitances of 188 F/g and 426 F/g at a scan rate of 10 mV/s, respectively. Furthermore, they demonstrated impressive energy and power densities, with MoS₂ achieving 21.81 Wh/kg at 399 W/kg, while the composite reached 39.16 Wh/kg at 499.46 W/kg. Additionally, we developed quasi-solid-state symmetric and asymmetric supercapacitors, which achieved specific capacitances of 328 F/g and 167 F/g at a scan rate of 10 mV/s, respectively. The specific energy and power densities were measured at 19.24 Wh/kg at 1058.901 W/kg and 44.53 Wh/kg at 1279.9 W/kg, respectively. Moreover, the capacitance retention of symmetric supercapacitor delivers 85% after 5000 charge–discharge cycles at a current density of 10 A/g. This synergistic approach, combining MoS₂ and TiO₂, shows significant potential for the rational design of high-performance electrode materials in energy storage applications.