Electrochemical method integrating exfoliation and in-situ growth to synthesize MoS2 nanosheets/MnO2 heterojunction for performance-enhanced supercapacitor

Abstract

Two-dimensional (2D) molybdenum disulfide (MoS2) nanomaterials have become one of the promising options for constructing excellent supercapacitors. However, the application of MoS2 materials is limited by low energy density, and the difficulty of large-scale and low-cost preparation seriously hinders its practical application in the field of energy storage. Here, the exfoliation of the MoS2 nanosheets and the loading of MnO2 nanoparticles on the MoS2 nanosheets are realized in one step by electrochemical method. A series of characterization methods have fully confirmed that the electrochemical method has successfully prepared the MoS2 nanosheet/MnO2 (MoS2 NS/MnO2) heterojunction. The experimental results show that the MoS2 NS/MnO2 heterojunction has better electrochemical performance than a single MoS2 nanosheet. It has a good capacitance even in a neutral solution, and its specific capacitance is 275 F g−1 at a current density of 2 A g−1. In addition, a supercapacitor device based on MoS2 NS/MnO2 heterojunction was constructed, which not only exhibited excellent capacitive performance, but also exhibited 10,000 charge-discharge cycle stability under 10 A g−1 conditions. This work provides an experimental basis for the preparation of 2D nanosheets and the large-scale preparation of functionalized 2D material heterojunctions by electrochemical methods.