In the present study, the electropolymerization (template synthesis) and then fabrication of symmetrical supercapacitors based on single and multilayered multiwalled carbon nanotube/polyaniline (MWCNT/PA) is achieved. It is found that the morphology and capacitance values depend strongly on the nature and concentration of electrolytes. The presence of micro and mesopores on the MWCNTs provides the space for the deposition of PA on them. The extended conjugation results due to the overlapping of π electron cloud of sp2 hybridized carbon network of MWCNT with quinoid rings of three layers of PA doped with three dopants. This leads to the highest capacitance of 333 F g−1 and good charge–discharge cycling behavior with 85% charge retention at 1000 cycles for the symmetrical supercapacitor based on the multilayered composite material.

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As the human population increases, there is invariably excessive demand for energy sources, thus making it a fundamental need. The basic use of supercapacitors is the storage of energy. But self-discharge is caused when no external power or internal battery is charging them. This clearly reduces their efficiency. It has been found that self-discharge can be reduced to a great extent by employing liquid crystals (LC). But the effect of LC in enhancing the supercapacitor properties has not been discussed. So here, the naturally available bentonite clay is analyzed for its lyotropic liquid crystalline (LLC) properties. It showed liquid crystalline properties at 0.055 g/cm3 in 0.2 M Na2SO4 solvent. It is characterized by a polarised optical microscope (POM). These LCs are added as an additive electrolyte to the supercapacitors. The electrode materials used for supercapacitors are a composite of activated carbon and polyaniline. When compared, the supercapacitor properties were enhanced with a decrease in IR drop in supercapacitors containing bentonite lyotropic liquid crystal, producing a specific capacitance of 237.5 F/g at a current density of 0.5 mA/cm3. The electrochemical behavior of the supercapacitors is determined by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge cycling techniques. Graphical Abstract

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In the present study, energy harvesting is done from carbon fibers (CFs) synthesized using a naturally available broomstick and bamboo stick. The broom and bamboo sticks have been reprocessed in an alkaline solution using a controlled hydrothermal method. The carbonization of the cellulose fibers resulted in the production of CFs. The synthesized CFs have been used to prepare a ternary composite electrode with MnO2 and polyaniline (PA). Thus, prepared ternary composite electrodes were used for the supercapacitor application. The Supercapacitor with a maximum specific capacitance (SC) of 373 F/g (from Broomstick) and 132 F/g (from the bamboo stick) was fabricated, which showed good cycling stability. The structural properties of the electrode materials were confirmed using X-ray diffraction, scanning electron microscopy, EDAX, BET adsorption-desorption experiment, and Fourier transform infrared spectroscopy techniques. The fabricated symmetrical electrode's supercapacitor properties were analyzed using cyclic voltammetry (CV), electrochemical impedance, and galvanostatic charge-discharge (GCD) cycling technique.