Preparation and electrochemical properties of MnO2/PANI-CNTs composites materials

Abstract

ABSTRACTIn this article, carbon nanotubes (CNTs) was modified with conducting polymer polyaniline (PANI) to produce composite supporters (PANI-CNTs), and then the MnO2/PANI-CNTs composite material was prepared by hydrothermal route through the oxidation of manganese sulfate using ammonium persulphate (APS) as oxidizing agent. XRD, FT-IR, SEM and laser Raman spectroscopy were used to characterize the composition and structure of materials, meanwhile the electrochemical properties of the material were also investigated. In addition, a series of materials such as MnO2, MnO2-CNTs, MnO2-PANI with different supporters were also prepared to investigated the support effects on the structure and electrochemical properties of composite materials. The characterization results show that the dispersion of MnO2 in composites was greatly affected by the constitution of supports. In comparison with poor MnO2 dispersion on MnO2/CNTs, as for the composite materials including PANI, the anchoring of Mn2+ through covalent bond between PANI and Mn2+, which would help to disperse the MnO2, and then uniform ‘starfish-type’ MnO2 was achieved on MnO2/PANI-CNTs composite. Moreover, the addition of PANI would improve the conductivity of composite materials. In conclusion, high electrical conductivity and MnO2 dispersion on MnO2/PANI-CNTs composite results in higher specific capacitance (391F/g), which was triple value of specific capacitance for pure MnO2 (132 F/g). Moreover, high specific capacitance retention (90%) for MnO2/PANI-CNTs composite displays good electrochemical stability in comparison with other composites.