Synthesis Of PANI And PANI/MnO₂ Composite As Supercapacitor Electrode Materials By Oxidation Process With Oxidant Of MnO₂

In this paper, MnO₂ was used as the template and the oxidant to prepare PANI (MnO₂ template could be spontaneously removed after the reaction) and MnO₂/PANI composite (MnO₂ is the supercapacitor electrode material) which show excellent electrochemical property. The structure were analyzed by XRD, SEM, FT-IR, EDS, BET and XPS, and the supercapacitive behaviors of these nanotubes were investigated with cyclic voltammetry (CV), charge–discharge tests, impedance spectroscopy and long-term electrochemical stability, respectively. Firstly, MnO₂ templates (oxidant) are synthesized by hydrothermal synthesis method at different temperature. Bird's nest-likeα-MnO₂ was prepared under low temperature while firework-likeα-MnO₂ was prepared under the high temperature. The temperature and time of hydrothermal synthesis are the most important influencing factors of morphology and specific capacitance. The maximum specific capacitance of 917 F/g could be achieved in aqueous KOH. Secondly, PANI samples were prepared by oxidative polymerization. The morphology of the synthesized PANI basically replicate that of MnO₂ template except for the nanotube structure of single branch. It should be noted that the surface of PANI nanotubes are covered with nanoparticles. MnO₂ template is the most important influencing factors of morphology and specific capacitance. If the amount of aniline is increased while the amount of MnO₂ template is constant, a crosslink based on PANI nanoparticles occurs among different nanotubes, the specific surface area is large and the special channel structure is formed. The maximum specific capacitance of 533 F/g could be achieved in aqueous H₂SO₄ and the large current discharge performance improve with increasing the amount of aniline under laboratory conditions of this paper. Finally, if the amount of aniline is decreased while the amount of MnO₂ template is constant, MnO₂/PANI composite could be prepared. The maximum specific capacitance of 449 F/g and excellent large current discharge performance could be achieved in aqueous H₂SO₄ when the amount of aniline is 2 mL.