Edinburgh Napier University

  Flexible electrochemical capacitors (EC) or supercapacitors are found to be an efficient energy storage device for modern and future electronic gadgets that offer lightweight and compact energy solutions. In this work, we investigated the electrochemical and energy-storing performances of a flexible ZnO-carbon black (ZnO-CB) composite-based EC. The prepared ZnO-CB composite electrode exhibits a conductivity of 60.75 kS/m and it shows rough surface morphology which was observed through the scanning electron microscopic images. The cyclic voltammetry analysis reveals that the flexible ZnO-CB composite-based EC has a specific capacitance of 99.21 mF.cm−2 and a charge contribution of 0.198 C.cm−2 at a low scan rate of 1 mV.s−1. The energy density of the EC gives 13.80 µW.h.cm−2 at 1 mV.s−1 and 0.53 µWh.cm−2 at 100 mV.s−1. The energy storing performances are also observed through galvanostatic charging discharging analysis and provides a specific capacitance of 5.70 mF.cm−2 with energy and power densities of 54.11 µW.h.cm−2 and 0.104 mW. cm−2 respectively at a current density of 0.25 mA.cm−2. The bendability study of the device carried out in angles of 20°, 40° and 60° predicts its energy-storing performance under various bending angles. The observed energy-storing performances of the EC reveals its potential as a power source for operating flexible and wearable devices.