Graphene based PANI/MnO₂ nanocomposites with enhanced dielectric properties for high energy density materials

The high energy density materials driven by high storage permittivity are in huge demand due to their extensive applications in capacitors used in electric trains, hybrid electric vehicles, and aircraft. Nanocomposites, especially with conducting polymer exhibit characteristic properties such as well-organized framework, extensible, and rich dielectric strength, suitable for high-energy storage materials. The judicious choice of nanofillers for a given polymer matrix largely dictates the property enhancement in polymer nanocomposites. Herein, we explore GO, RGO and MnO₂ as nanofillers to make binary (PANI-GO and PANI-RGO)and ternary nanocomposites (PANI-GO-MnO₂ and PANI-RGO-MnO₂)of PANI. The PANI-RGO-MnO₂ ternary nanocomposite exhibits an excellent dielectric property owing to its hexagonal nanorods structure, as revealed by detailed morphological analysis. The in-situ polymerization of PANI ensures the formation of nanocomposites with uniform dispersion of MnO₂ nanorods and RGO nanoflakes, which in turn yields high dielectric constant with excellent charge polarization. The frequency dependent study shows that the nanocomposites are quite stable over a long range of frequency, suitable for energy storage devices where high frequency is applied. The combination of high energy density with high breakdown strength indicates the potential applications of the nanocomposites in electrostatic capacitors and fabrication of high frequency dependent electronic components.