Ternary nanocomposite of polyaniline/manganese dioxide/titanium nitride nanowire array for supercapacitor electrode.

The electroactive polyaniline (PANI) and manganese oxide (MnO) were integrated with titanium nitride (TiN) nanowire array (NWA) to form PANI/MnO/TiN ternary nanocomposite for supercapacitor application. TiN NWA was prepared via a seed-assisted hydrothermal synthesis and ammonia nitridization process. The electroactive MnO and PANI was layer-by-layer coated on TiN NWA to form heterogeneous coaxial structure through a stepwise electrodeposition process. Scanning electron micrographs revealed that the well-separated TiN NWA was composed of well-distributed nanowires with diameters in the range of 10-30 nm and a total length of 1.5 μm. A villiform MnO layer with a thickness of 10-20 nm covered on TiN NWA to form MnO/TiN NWA composite. The coral-like PANI layer with thicknesses in the range of 20-50 nm covered on the above MnO/TiN NWA to form PANI/MnO/TiN NWA. Electrochemical measurements showed that a high specific capacitance of 674 F g at a current density of 1 A g (based on total mass of PANI/MnO) was obtained for PANI/MnO/TiN NWA ternary nanocomposite, which was much higher than that of PANI/MnO/carbon-cloth composites reported previously. This ternary nanocomposite also showed a good rate and cycling stability. Moreover, in comparison with PANI/TiN NWA or MnO/TiN NWA, the specific capacitance of PANI/MnO/TiN NWA was obviously enhanced due to the extra pseudocapacitance contribution and the effective surface area of coral-like PANI layer, showing the advantage of manipulating the heterogeneous coaxial configuration between PANI and MnO for fundamentally improved capacitive performance. These results demonstrated that PANI/MnO/TiN NWA ternary nanocomposite was a promising candidate electrode material for supercapacitor application. [ABSTRACT FROM AUTHOR]