Exo-shoe triboelectric nanogenerator: Toward high-performance wearable biomechanical energy harvester

Abstract

Abstract Among various daily human motions, walking is considered the most natural and strongest one. In this study, the exo-shoe TENG (ES-TENG) with the rationally designed bi-directional gearbox is developed to generate extended and enhanced output performance during daily walking. This bi-directional gearbox effectively converts the whole stroke of a reciprocating and low frequency (1 Hz) natural stepping motion into uni-directional high-speed rotation (700 rpm). The proposed ES-TENG exhibits more than ten times enhancement of the output performance with effective motion transformation. Although the normal stepping motion is not interrupted by the ES-TENG, the specific power of the ES-TENG could reach up to 13 µW/g through a single daily stepping motion. Real-time self-powered environmental monitoring and charging wearable electronics are demonstrated as proof-of-concept applications. Furthermore, the voltage multiplier circuit is used to generate a boosted open-circuit voltage of more than 3 kV, which shows the potential electric treatment applications of the ES-TENG. The ES-TENG provides the potential of biomechanical energy harvesting with a broad range of applications through the generation of highly enhanced output performance under natural daily stepping motions.