Organic electrolytes for graphene-based supercapacitor: Liquid, gel or solid

The electrolyte is an important and decisive factor in battery, capacitor and supercapacitor fabrication. Here we report how electrolyte's provenance and structure effect on the electro-optical properties of the graphene-based supercapacitor. The three organic electrolytes were synthesized: liquid electrolyte, which on the basis of propylene carbonate (PC), gel electrolyte- polyvinyl alcohol (PVA) and solid electrolyte- polyvinylidene fluoride (PVDF). As an application, we demonstrate an optical modulator using supercapacitor structure built by graphene electrodes and prepared electrolytes. All organic electrolyte-based supercapacitors potentiate optical modulation of graphene electrodes over a broad range of wavelengths, under ambient conditions. We reveal higher capacitance (78 mu F/cm(2)) for a supercapacitor with gel electrolyte during various bias voltages. We represent the increasing of light transmission at 3 times using solid electrolyte, in comparison with liquid and gel electrolytes and illustrate the super capacitor possibility with gel electrolyte to operate under negative voltage. Consequently, we suggest applying of solid electrolyte as a more appropriate electrolyte for fabrication of graphene-based super capacitor. We anticipate that using of solid electrolyte allows us to get desired electro-optical properties, minimize the size of the device and vary it shape. (C) 2016 Elsevier Ltd. All rights reserved.