Weight ratio effects on morphology and electrocapacitive performance for the MoS2/polypyrrole electrodes

MoS2 is one of the promising electroactive materials for charge-storage devices. The charges cannot only be stored in the intersheet of MoS2 and the intrasheet of individual atomic layers, but also can be accumulated by conducting the Faradaic reactions on the Mo center. To further enhance the electrocapacitive performance of MoS2, incorporating conducting polymers is one of the feasible ways to improve the connection between MoS2 nanosheets. At the same time, the growth of conducting polymers can also be controlled via incorporating MoS2 nanosheets in the synthesis to enhance the conductivity and increase the specific surface area of the conducting polymers. In this work, layered structures of MoS2 nanosheets are successfully synthesized via a simple hydrothermal method, and pyrrole monomers are oxidative polymerized in the MoS2 solution to prepare the nanocomposites with different ratios of MoS2 and polypyrrole (Ppy). The optimized MoS2/Ppy electrode shows a specific capacitance (CF) of 182.28 F/g, which is higher than those of the MoS2 (40.58 F/g) and Ppy (116.95 F/g) electrodes measured at the same scan rate of 10 mV/s. The excellent high-rate capacity and good cycling stability with 20% decay on the CF value comparing to the initial value after the 1000 times repeated charge/discharge process are also achieved for the optimized MoS2/Ppy electrode. The better performance for the MoS2/Ppy electrode is resulting from the larger surface area for charge accumulation and the enhanced interconnection networks for charge transportation. The results suggest that combining two materials with complementary properties as the electrocapacitive material is one of the attractive ways to realize efficient charge-storage devices with efficient electrochemical performances and good cycling lifes.