Plasma treatment of bismuth-doped MoS2 with excellent supercapacitor performance

Abstract

As a layered transition metal dichalcogenide (TMD) with a two-dimensional structure akin to graphene, molybdenum disulfide (MoS₂) features a unique architecture that enhances surface area and facilitates ion transport-crucial for applications in batteries and supercapacitors. In this study, we detail a simple hydrothermal method for preparing bismuth (Bi)-doped MoS₂, followed by 200 W plasma treatment. Chemical doping with Bi significantly improves the electrical conductivity of MoS₂, which enhances interactions with electrolytes and accelerates ion migration. Plasma treatment enhances the properties of Bi-doped MoS₂ by modifying its surface characteristics and improving charge carrier mobility. It activates reactive sites, facilitating better alloy formation, and enhances the stability and electronic performance of MoS₂. The resulting plasma-treated Bi-doped MoS₂ electrodes exhibit remarkable supercapacitor performance, including a wide potential window of 1.1 V, a specific capacitance of 183 F g⁻¹ at 1 A g⁻¹, and an excellent cycling stability, retaining 80% of the capacity after 10 000 cycles at 15 A g⁻¹. Furthermore, a symmetric supercapacitor (SSC) device is assembled by PT-MoS₂@Bi on carbon cloths as both the positive and negative electrodes. The SSC device demonstrates outstanding flexibility, high energy density, and power density. This work presents an effective approach to enhance the electrochemical performance of MoS₂ through a combination of chemical doping and physical plasma treatment.