A human locomotion inspired hybrid nanogenerator for wrist-wearable electronic device and sensor applications

To reduce battery dependency in wearable IoT devices, this work demonstrates a novel curve-shaped wearable hybridized electromagnetic-triboelectric nanogenerator (WHEM-TENG). This fully-enclosed, light-weight harvester is driven by low-frequency human motion, incorporating the arm's swinging behavior and a freestanding rolling magnetic ball. The device was fabricated using cost-effective 3D-printing.

• Development of a novel wearable hybridized electromagnetic-triboelectric nanogenerator (WHEM-TENG).
• Design inspired by human arm swinging motion during locomotion.
• Use of 3D-printing for fast, easy, and cost-effective fabrication.
• Demonstrated capability to power a commercial electric wristwatch and a self-powered heart-rate sensor.

The harvester was designed using simulations of magnetic flux density and triboelectric surface potential. It was then fabricated using 3D-printing, with the printing material itself serving as a triboelectric layer. The device's performance was tested by measuring the power output of both the electromagnetic generator (EMG) and triboelectric nanogenerator (TENG) components under simulated walking and running frequencies.

At low frequencies, the EMG and TENG delivered peak power densities of 5.14 mW/cm³ and 0.22 µW/cm³, respectively. The WHEM-TENG powered a commercial wristwatch continuously for 410 seconds after only 5 seconds of running activity. A self-powered heart-rate sensor was also successfully demonstrated.