Preparation Of Manganese Oxide/ Poly-O-phenylenediamine Composite And Its Application In Supercapacitor

Manganese oxide nanowires/poly-o-phenylenediamine composite material have been designed and synthesized. The material has been applied to supercapacitor. The main points of this paper are described as follows:Two forms of nano-dimension manganese dioxide:manganese dioxide nanowires and manganese dioxide nanoparticles have been prepared through different methods. Modified manganese oxide material (MnO@PoPd) with better electrochemical performances has been prepared. The materials have been further characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry method to analyze its morphology, crystal and electrochemical properties. The temperature of 180℃ is appropriate for manganese dioxide nanowires prepared through hydrothermal method, the nanowires shape performs better in the polymerization process than the nanoparticles, and the appropriate polymerization time should be 3 h.Manganese dioxide nanowire has been selected as the template on which the polymerization of o-phenylenediamine should take place, and a high temperature treatment has been conducted to obtain the manganese oxide nanowire/poly-o-phenylenediamine composites (MnO@PoPd). The MnO@PoPd were further characterized by many effective measurements, such as X-ray diffraction(XRD), infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), BET-surface area analysis, confirming that MnO@PoPd has got better conductivity (4.167×10-3 S cm-1), higher specific surface area 87 m2 g-1 and a suitable pore size distribution (～3.7 nm).MnO@PoPd has been used to prepare working electrode with nickel foam. Cyclic voltammetry (CV), galvanostatic charge-discharge tests and AC impedance tests have been conducted to investigate the electrochemical properties, the specific capacitance and stabilities of the materials. The obtained results showed that, the electric capacity was increasing with the treat temperature and the MnO@PoPd-650 has excellent charge and discharge performance and reached a maximum value of 269.40 F g-1. Manganese dioxide nanowire/ activated carbon composites (MnO2@AC) has also been studied, compare with it, MnO@PoPd composite has better reversibility, greater capacitance and higher power density and energy density.