A robust hybrid nanogenerator strategy achieved by regenerative motion transmission toward wind energy harvesting and self-powered sensing

Abstract

In rotary-sliding triboelectric-electromagnetic hybrid nanogenerator (RS-TEHG) for wind energy harvesting, the triboelectric nanogenerator (TENG) unit and electromagnetic generator (EMG) unit normally share the same rotor. Hence, the sliding friction between triboelectric layers leads to not only severe material abrasion but also restricted rotor speed and reduced electric outputs of both units. To address this issue, a regenerative motion transmission (RMT) mechanism is proposed herein to implement efficient TEHG (RMT-TEHG) by mechanically connecting TENG and EMG in series. Consisting merely of two cylinders, the RMT mechanism can not only markedly reduce frictional resistance and improve robustness by transforming sliding friction to rolling friction but also work as both a triboelectric pair and a friction pair for driving EMG as well as realizing self-contained sensing of RMT working state, achieving the functionalization of the frictional resistance. With significantly reduced frictional resistance, RMT-TEHG can operate at a low wind speed of 2.5 m/s and its TENG unit can maintain 98.9% electric output after 100,000 working cycles; by contrast, RS-TEHG has a high start-up wind speed of 5.1 m/s and the TENG unit only retains 60.3% output. As actuated by 4.5 m/s wind, RMT-TEHG can deliver 88.4 mW electrical power and sustain the continuous operation of a wireless multifunctional environmental sensing system. This work presents a distinctive strategy for constructing robust and efficient hybrid nanogenerators toward wind energy harvesting and self-powered wireless sensing systems.