Environmental friendly solid blend polymer electrolytes based on PVA:starch:ceric ammonium nitrate for electric double layer capacitor (EDLC) applications

The solid blend polymer electrolytes based on polyvinyl alcohol/cassava starch are prepared by solution casting technique. The amorphous nature of the polymer electrolytes is analyzed by X-ray diffraction pattern. Fourier transform infrared spectra affirms the complexation between salt and blend polymers. The thermal behavior of solid polymer electrolyte was carried out by thermo-gravimetric analysis at 30–500 °C at nitrogen atmosphere. The surface morphology and EDAX spectrum of prepared high conducting electrolyte are observed in the SEM image. The impedance spectroscopy technique is used to measure the ionic conductivity values in frequency range of 42 Hz–1 MHz at room temperature. The maximum ionic conductivity of 1.53 × 10−5 S/cm is observed for 2% of salt doped system. Through electrochemical studies of electric double layer capacitor device, the non-faradaic behavior is observed. From linear sweep voltammetry analysis, the potential window of the higher conducting sample is obtained as − 2 to + 2 V. By analyzing cyclic voltammetry graph, the specific capacitance values are obtained and it denotes that increasing scan rate decreases the specific capacitance value. At low scan rate of 25 mV s, the specific capacitance value is 16 F/g, and for 100 mV s, it is 4.5 F/g. Charge–discharge studies of device appear linear slope and energy density, and power density values are observed from the number of cycles.