Bow-type bistable triboelectric nanogenerator for harvesting energy from low-frequency vibration

Triboelectric nanogenerators (TENGs) are emerging, leading-edge, and promising devices for converting ambient vibration energy into electrical energy and power for low-power sensors. However, it is difficult to harvest energy from low-frequency ambient vibrations using conventional TENGs. To solve this issue, in this study, we propose a bow-type TENG with a bistable stiffness feature, which enables the conversion of low-frequency vibration energy into electrical energy with high efficiency. The dynamic model of the bow-type TENG was established based on extended Hamilton's principle and numerically solved to obtain the dynamic responses. Subsequently, a prototype of the bow-type TENG was fabricated and tested to verify the design concept. Moreover, the dependencies of the energy-harvesting performance on the structural parameters were experimentally investigated. The average power had a maximum value of 0.64 mW at 5 Hz in the case of optimal load resistance. The bow-type TENG could power a number of light-emitting diodes (LEDs) to display the word "HNU" under low-frequency excitation. Hence, the bow-type TENG can substantially extend the function of harvesting vibration energy from high to low frequencies.