ABSTRACT
Nanocomposite polymer electrolytes (NCPEs) are prepared using solution casting technique. Poly(acrylic acid) (PAA), lithium bis(trifluoromethane)sulfonimide (LiTFSI) and nano-sized barium titanate (BaTiO3) are used as polymer, doping salt and filler respectively. Ferroelectric material, BaTiO3 is a promising material in polymer electrolyte preparation because there is an abrupt change in ionic conductivity, which is from 1.04 μS cm−1 to 0.5 mS cm−1 upon addition of 8 wt.% of BaTiO3. The ionic conduction mechanism of polymer electrolytes obeys the thermally activated principle which is related to the Arrhenius theory. These filler-added polymer electrolytes exhibit better thermal and electrochemical properties in comparison to filler-free polymer electrolyte. Addition of this ferroelectric material can reduce the glass transition temperature (Tg) of polymer electrolytes. Electric double layer capacitors (EDLCs) are fabricated using filler-free polymer electrolytes or the most conducting nanocomposite polymer electrolytes and carbon-based electrodes. The electrochemical properties such as capacitance, energy density, power density and Coulombic efficiency of the cells are scrutinized through cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analyses. The nanocomposite polymer electrolyte-based EDLC achieves the specific capacitance of 25 Fg−1 which is higher than that of filler free polymer electrolyte. The electrochemical stability of the cell is also studied by charging and discharging the cell over 20,000 cycles. The nanocomposite polymer electrolyte is a good candidate as the specific capacitance of the cell is decreased gradually upon 20,000 charging cycles.
