Capacitor-Integrated Triboelectric Nanogenerator Based on Metal–Metal Contact for Current Amplification

The electrical power of triboelectric nanogenerators (TENGs) is increased by surface modifications, and they can successfully power portable devices alone. However, modifying the material and its surface may limit the device lifetime, and most of the portable applications demonstrated in previous studies have excessive input conditions. In this study, a capacitor-integrated TENG (CI-TENG) that uses the fundamental mechanisms of the Leyden jar is developed. In this device, a long sheet metal (capacitor electrode)–polymer–metal composite (TENG electrode) is rolled inside the casing cylinder, and a capacitor unit is fabricated at the end of the sheet composite. This new operating mechanism of the CI-TENG is analyzed in terms of the dielectric constant of the capacitor unit and the metal-to-metal contact between electrodes. By instantaneous charging and discharging of the capacitor unit inside the CI-TENG, it can generate a peak open-circuit voltage of 156 V and a peak closed-circuit current of 4.3 mA under manual input. It charges a capacitor more than three times faster than a conventional TENG does. Furthermore, the internal impedance of the CI-TENG is decreased to 200 kΩ without any external circuit.