Coaxial double helix structured fiber-based triboelectric nanogenerator for effectively harvesting mechanical energy.

Harvesting energy from the surrounding environment, particularly from human body motions, is an effective way to provide sustainable electricity for low-power mobile and portable electronics. To get adapted to the human body and its motions, we report a new fiber-based triboelectric nanogenerator (FTNG) with a coaxial double helix structure, which is appropriate for collecting mechanical energy in different forms. With a small displacement (10 mm at 1.8 Hz), this FTNG could output 850.20 mV voltage and 0.66 mA m current density in the lateral sliding mode, or 2.15 V voltage and 1.42 mA m current density in the vertical separating mode. Applications onto the human body are also demonstrated: the output of 6 V and 600 nA (3 V and 300 nA) could be achieved when the FTNG was attached to a cloth (wore on a wrist). The output of FTNG was maintained after washing or long-time working. This FTNG is highly adaptable to the human body and has the potential to be a promising mobile and portable power supply for wearable electronic devices.