Bentonite Clay Liquid Crystals for High-Performance Supercapacitors
M. K. Neelamma, Sowmya R. Holla, M. Selvakumar, Parvathi Chandran, Shounak De
Abstract
Abstract 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/cm 3 in 0.2 M Na 2 SO 4 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/cm 3 . The electrochemical behavior of the supercapacitors is determined by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge cycling techniques. Graphical Abstract