Airflow‐Driven Triboelectric‐Electromagnetic Hybridized Nanogenerator for Biomechanical Energy Harvesting

Abstract The increasing use of wearable electronics calls for sustainable energy solutions. Biomechanical energy harvesting appears as an attractive solution to replace the use of batteries in wearables, as the body generates sufficient power to drive small electronics. In particular, triboelectric nanogenerators (TENGs) have emerged as a promising approach due to its lightweight and high power density. In this work, a TENG is hybridized with an electromagnetic generator (EMG) to harvest energy from the foot strike. An enclosed radial‐flow turbine is optimized and used to convert the foot‐strike low‐frequency linear movement into a higher‐frequency rotational motion (by a factor of ≈12). Besides increasing the motion frequency, the employed mechanism is physically robust and enables a continuous operation from irregular mechanical excitations. A single TENG unit operating in the freestanding mode generated an optimal power of 4.72 µW and transferred a short‐circuit charge of 2.3 nC. The TENG+EMG hybridization allows to power a digital pedometer even after the mechanical input stopped. Finally, the energy harvester is incorporated into a commercial shoe to power the same pedometer from foot walking. The obtained results validate the developed prototype ability to serve as a portable power source that can drive sensors and wearable electronics.