High-yield preparation of molybdenum disulfide/polypyrrole hybrid nanomaterial with non-covalent interaction and its supercapacitor application

Abstract

• High-yield of molybdenum disulfide (MoS 2 ) nanosheets could be prepared by simple grinding and sonochemical exfoliation. • Polypyrrole/MoS 2 (MPY) hybrid was synthesized via a chemical oxidative polymerization according to pyrrole content. • Non-covalent Mo–N bonding of MPY made it possible to have lowered interfacial resistance and improved surface conductivity. • MPY electrodes showed enhanced specific capacitance and electrochemical stability for pseudocapacitive behavior. Molybdenum disulfide (MoS 2 ) incorporated with a conducting polymer can be a promising nanomaterial for use as low-cost electrodes in supercapacitors. MoS 2 nanosheets are generally prepared by the high-pressure hydrothermal method, which has a few drawbacks such as low exfoliation yield, safety issues, and long-time processing. Herein, we report a simple and effective method for the high-yield (~72.5%) preparation of a MoS 2 /polypyrrole (MPY) hybrid nanomaterial via sonochemical exfoliation of ground bulk MoS 2 in a polar aprotic solvent and subsequent chemical oxidative polymerization of pyrrole (PY) onto the MoS 2 nanosheets. The strong non-covalent Mo–N bonding lowers the interfacial resistance, and the morphology of polypyrrole (PPY) can be easily controlled by varying the PY content. The MPY hybrid nanomaterial exhibited a maximum surface conductivity of 991 S sq., which is very high compared to that of pristine MoS 2 nanosheet (~3.6 × 10 –7 S sq.). When used in supercapacitors, the specific capacitance of the hybrid nanomaterial is 312 F g –1 . Thus, improved capacitance retention with increase in the scan rate and enhanced diffusion process during electrochemical reactions result in good supercapacitor performance, which is important for the mass production of energy-storage devices.