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

Harvesting the vibration energy commonly found in engines,aircompressors, and other machines is of great significance for energyrecovery and reutilization. However, due to the small vibration amplitudeand non-single vibration directions, the conventional vibration energyharvesters based on triboelectric nanogenerators (TENGs) have a lowefficiency. In this work, we proposed a TENG with a rotational freestandingmode (RFM-TENG), which can effectively harvest the mechanical vibrationenergy with a small amplitude, high frequency, and multiple directions.The working principle and performance characteristics of each TENGunit were demonstrated through theoretical analysis and electricalsimulations. To further improve the harvest efficiency, we prepareda room-temperature vulcanized silicone rubber (RTV) film doped withhigh dielectric constant halloysite nanotubes powder as the triboelectriclayer, which increased the open-circuit voltage by 100% and the short-circuitcurrent by 85% at an optimal doping ratio of 7 wt %. When the RFM-TENGwas installed on an air compressor, it generated an open-circuit voltageof about 60 V and a maximum output power of 45 & mu;W and allowed30 commercial LEDs to light up simultaneously. RFM-TENG has the advantagesof strong nonlinearity, high sensitivity, and multi-directional responseand has potential applications in the field of smart factory and digitaltwin.