Polypyrrole nanostructures//activated carbon based electrode for energy storage applications

In this study, a self-assembled polypyrrole nanostructure with the high electrochemical performance was synthesized via a chemical polymerization method. The structure, morphology and compositional analysis were investigated using Fourier transmission infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM) and X-ray photoelec-tron spectroscopy (XPS). The FTIR analysis of the synthesized samples confirmed the presence of pyrrole chain located at 1313 cm^-1. The XPS spectrum showed the presence of C1s and N1s binding energy peaks. The FESEM images confirmed the presence of self-assembled nanostructures with a size range of ~ 200 nm. The effect of various aqueous electrolytes on the electrochemical performance of polypyrrole was studied. Because of its smaller hydration sphere radius, increased molar conductivity and higher ionic mobility, self-assembled polypyrrole nanostructure (P1) delivered a high specific capacitance of 623 F g^-1 in 0.5 M H₂SO₄ electrolyte. Finally, we have fabricated a solid-state symmetric (SSC) and asymmetric super-capacitor (ASC) based on polypyrrole electrode. Among them, the as-assembled P1//activated carbon-based ASC delivered a maximum energy density (25.3 Wh kg^-1) and power density (2400 W kg^-1) with excellent cycling stability after 40,000 charge/discharge cycles.