Polymer based nickel ferrite as dielectric composite for energy storage applications.

• A series of nanocomposites of GO/NiFe 2 O 4 /PPy with different weight percentages of GO and NiFe 2 O 4 was synthesized. • XRD analysis revealed the presence of pure spinel phase of NiFe 2 O 4 and a broad hump for PPy. • The observed Maxwell-Wagner interfacial polarization was in agreement with multilayer capacitors formation in Koop's theory. • The formation of one and two semi-circles in Nyquist plot revealed grain boundaries and grains impedance effect, respectively. • These nanocomposites are favorable for energy storage devices. Graphene oxide (GO) and polymer based nanocomposites are emerging as a new class of materials having potential for flexible electronic devices and modern day energy storage devices. The traits like high mechanical strength, non-corrosive nature, low weight, being cost-effective, flexible, thermal and electrically insulated have made polymer based nano architectures highly effective for utilizing in energy storage applications. In the present research, the variation in structure, morphology and dielectric response of polypyrrole (PPy) is investigated by adding the nickel ferrite (NiFe 2 O 4) and GO in it. The nano-materials, PPy, NiFe 2 O 4 and GO were prepared by pyrrole's polymerization, sol‒gel auto-combustion method and modified Hummer's method, respectively. The solution mixing method was carried out to form GO/NiFe 2 O 4 /PPy nanocomposites with different concentrations by slowly mixing the already equipped nanomaterials. X-ray diffraction technique was employed for phase identification of as-prepared nanocomposites. The surface study and elemental composition was examined via field emission scanning electron microscope and energy dispersive X-ray spectroscope, respectively. The dielectric response of these samples was probed using impedance analyzer that was found to be in good agreement with Maxwell-Wagner model and Koop's Phenomenological theory. Effective contribution of different electro-active regions was investigated from Nyquist plots. [ABSTRACT FROM AUTHOR]