DC Voltage Modulation for Integrated Self-Charging Power Systems of Triboelectric Nanogenerators and Ion Gel/WO₃ Supercapacitors

A triboelectric nanogenerator (TENG) is an attractive alternative source of electric power generation; however, its direct use is difficult due to the spike-like alternating current (AC) output. This study presents the achievement of direct current (DC) output voltage and its modulation to a target value. A full-wave bridge rectifier is used for DC conversion and a gel electrolyte-based supercapacitor (ion gel/WO3) is used as a charge storage unit to form an integrated self-charging power system. The relaxation profile of the ion gel/WO3 supercapacitor increases the charge relaxation time considerably by a large offset voltage compared to a simple ion gel capacitor without WO3. We show that the constant DC output voltage can be modulated by adjusting the contact area of TENG, contact frequency, and serial/parallel connection of the supercapacitors.