The development of promising microwave absorbing materials is a booming field of research in both the commercial and defense sectors to prevent electromagnetic pollution, and also to enrich the field of stealth technology. Supercapacitors are a symbol of clean energy storage devices. The present work attends to the preparation of hexagonal shaped magnetic M-type hexaferrite, CuFe 10 Al 2 O 19 (CFA) by a facile chemical co-precipitation method, and the formation of its composites (graphene/CFA) in the presence of acid modified graphene. An in situ approach was employed for the coating of graphene with CFA. Another nanocomposite (graphene/CFA/PANI) was prepared by the wrapping of graphene/CFA with polyaniline (PANI), which was prepared through the in situ chemical oxidation polymerization of aniline.The prepared multifunctional nanocomposites showed an outstanding and improved microwave absorption property (the maximum reflection loss was À63.6 dB at a thickness of 2.5 mm with a broad absorption range) and electrochemical properties (the highest specific capacitance value was 342 F g À1 ), in contrast to the pristine graphene and CFA. The addition of PANI also improves the microwave absorption and specific capacitance of the nanocomposites. The formation of the multifunctional nanocomposites and their structural characteristics are discussed thoroughly with their impact on the two different fields of applications i.e. microwave absorbing and energy storage device applications individually.

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The demand for superior energy storage devices, such as supercapacitors, has been growing to meet the application requirements of hybrid vehicles and renewable energy systems. Here, we report a simple method to synthesize manganese chloride (MnCl2)-doped polyaniline (PANI)/single-walled carbon nanotubes (SWCNTs) nanocomposites for electrochemical supercapacitors. The possible interactions between MnCl2 and both PANI and SWCNTs was studied by Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, and Raman spectroscopy. The morphological characteristics of the electrode materials were investigated by field emission scanning microscopy (FESEM) and transmission electron microscopy (TEM). As-prepared nanocomposites showed higher electrical conductivity of 9.65 S/cm at room temperature and reached nonlinear current–voltage characteristics. A maximum specific capacitance of 546 F/g has been obtained for the nanocomposites at 0.5 A/g current density. Transition metal doping and SWCNTs enhance the electrochemical properties of the nanocomposites. The better specific capacitance and charge/discharge rates make them promising candidates as electrodes in supercapacitors, combining high energy densities with high levels of power delivery.

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Graphene, an extraordinary allotropy of carbon, the 2D nanosheet, have been synthesized through exfoliation of graphite in ortho-dichloro benzene by sonication. The morphological changes in different interval of sonication have been investigated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Raman Spectra confirmed the formation of defect free Graphene sheets. As prepared Graphene showed high thermal stability under N 2 atmosphere. It has been observed that sonication for 4 hours, effectively exfoliates graphite to form Graphene sheets. However, further sonication leads to restacking of Graphene sheets. The formation of Graphene is supposed to be due to the Sonopolymerization of the solvent (ortho-dichloro benzene) and graphite-solvent interaction.

Herein, we report a cost-effective and easy synthetic procedure for the fabrication of a graphene–single-walled carbon nanotube–poly­(3-methylthiophene) ternary nanocomposite for high-performance supercapacitor electrodes. The possible interactions of both graphene (Gr) and single-walled carbon nanotubes (SWCNTs) with poly­(3-methylthiophene) (PMT) were characterized by Fourier transform infrared, UV–visible, and Raman spectroscopies. A morphological study confirmed the formation of a bridge between PMT-coated SWCNTs and Gr layers. The ternary nanocomposite showed superior electrical conductivity of 4.68 S/cm at room temperature and also exhibited nonlinear current–voltage characteristics. The ternary nanocomposite achieved a maximum specific capacitance of 561 F/g at a 5 mV/s scan rate. Both a high energy density and a high power density were obtained for the ternary nanocomposite. Here, both the Gr and SWCNTs take part in the increment of the electrochemical properties. A higher thermal stability was also observed for the ternary nanocomposite. Based on its outstanding properties, the ternary nanocomposite is a potential candidate for a high-performance supercapacitor electrode.

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