Figure 3.

Electrochemical properties of the supercapacitor using the CNT electrodes. (a) The specific capacitances of the heat-treated electrodes at various temperatures as a function of the charging time at a charging voltage of 0.9 V, where the capacitance was measured at a discharging current of 1 mA/cm². (b) The specific capacitances of the heat-treated electrodes at various temperatures as a function of the discharging current density at a charging voltage of 0.9 V for 10 min. (c) The cyclic voltammetric (CV) behaviors (sweep rate, 100 mV/s) for the CNT electrodes at various heat-treatment temperatures. (d) The complex-plane impedance plots for the CNT electrodes for various heat-treatment temperatures at an ac-voltage amplitude of 5 mV, Z″: imaginary impedance, Z′: real impedance. ([54], Copyright @ Willey-VCH)