MnO₂/polypyrrole nanotubular composites: Reactive template synthesis, characterization and application as superior electrode materials for high-performance supercapacitors

A novel MnO₂/polypyrrole (PPy) heterogeneous composite with nanotubular structure is reported by a facile preparation of in situ chemical polymerization via a reactive template of MnO₂. MnO₂ nanotubes are found to be served as both appropriate oxidants and scaffolds to polymerize conducting PPy nanocoatings on the surface, thus constructing a unique coaxial configuration. The electrochemical measurements show that both components in the hybrid nanocomposites exhibit highly pseudocapacitive behavior in neutral KCl aqueous electrolyte. MnO₂/PPy nanocomposites prepared from an initial MnO₂/pyrrole ratio (3:1) deliver a maximum specific capacitance of 337 F g^-1 at 0.5 A g^-1 with good rate capability and long-term cycling stability, demonstrating their promising applications in high-performance supercapacitors. Moreover, the synthetic methodology may provide a generic guideline in developing different nanostructured MnO₂/PPy electrode materials for electrochemical energy storage.