Frequency Band Characteristics of a Triboelectric Nanogenerator and Ultra-Wide-Band Vibrational Energy Harvesting

Micromechanical vibration, as one of the most prevalent forms of energy in an ambient environment, has surpassing application potentials as the power source for self-powered electronics. A triboelectric nanogenerator (TENG) can effectively convert vibrational energy to electricity, which has the unique benefit of a wide-band over a traditional vibration energy harvester due to the contact electrification mechanism. Herein, the frequency band characteristics of vibrational TENG (V-TENG) were systematically elaborated. The mechanical model of V-TENG was established to explore its working mechanism for wide-band vibrational energy harvesting. By simulation analysis and experimental validation, the bandwidth dependence of V-TENG on acceleration magnitude, proof mass, stiffness, and gap distance was investigated in detail. With optimized structural parameters, an ultra-wide-band vibration energy harvester (UVEH) was developed by a tandem spring–mass structure. Within the ultra-wide-band range from 3 to 45 Hz, the UVEH can invariably illuminate 36 serial light-emitting diodes (LEDs) and charge a 33 μF capacitor to 1.5 V within 35 s. This work has quantitatively studied frequency band characteristics of V-TENG and provided a promising strategy for wide-band vibrational energy harvesting from a machine, bridge, water wave, and human motion.