Triboelectric Nanogenerator with a Rotational Freestanding Mode for Multi-directional Vibration Energy Harvesting

Harvesting the vibration energy commonly found in engines, air compressors, and other machines is of great significance for energy recovery and reutilization. However, due to the small vibration amplitude and non-single vibration directions, the conventional vibration energy harvesters based on triboelectric nanogenerators (TENGs) have a low efficiency. In this work, we proposed a TENG with a rotational freestanding mode (RFM-TENG), which can effectively harvest the mechanical vibration energy with a small amplitude, high frequency, and multiple directions. The working principle and performance characteristics of each TENG unit were demonstrated through theoretical analysis and electrical simulations. To further improve the harvest efficiency, we prepared a room-temperature vulcanized silicone rubber (RTV) film doped with high dielectric constant halloysite nanotubes powder as the triboelectric layer, which increased the open-circuit voltage by 100% and the short-circuit current by 85% at an optimal doping ratio of 7 wt %. When the RFM-TENG was installed on an air compressor, it generated an open-circuit voltage of about 60 V and a maximum output power of 45 μW and allowed 30 commercial LEDs to light up simultaneously. RFM-TENG has the advantages of strong nonlinearity, high sensitivity, and multi-directional response and has potential applications in the field of smart factory and digital twin.