Flexible contact pendulum friction nanogenerator for harvesting blue energy for marine applications

Collecting energy from low-frequency waves is really important for the development of the ocean IoT, but traditional rigid triboelectric nanogenerators (TENG) have a high starting threshold and wear out easily, which seriously limits their use in small waves. This article proposes a swing-type triboelectric nanogenerator (RS-TENG) based on the smooth contact of natural rabbit fur, aimed at efficiently harvesting low-frequency water wave energy. This device uses rabbit fur with extremely low friction and a PVC film to create a unique, soft ’brush-style’ contact. It greatly lowers the mechanical threshold for starting vibrations, allowing the pendulum to swing smoothly and continuously even under weak excitation, while also effectively reducing material wear. By systematically optimizing parameters like the friction distance, baffle angle, and pendulum counterweight, the TENG on the RS-TENG side achieved a maximum open-circuit voltage of over 360 V, a short-circuit current of 4.5 μA, and a transferred charge of 170 nC under a 2.25 Hz reciprocating drive. With a custom energy management circuit, the RS-TENG successfully lit up an array of hundreds of LEDs in a simulated water wave environment and achieved stable self-powered closed-loop operation for a commercial digital temperature and humidity meter. This study confirms that it’s feasible to develop high-sensitivity wave energy harvesting structures using bio-based flexible materials, providing power for in-situ sensor networks in simulated water environments and paving the way for future marine applications.