Bionic‐Fin‐Structured Triboelectric Nanogenerators for Undersea Energy Harvesting

Abstract In situ harvesting undersea energy is a vital method for undersea detector to realize its long‐term and real‐time undersea research. Herein, inspired by the fins with excellent hydrodynamic characteristic and the triboelectric nanogenerator (TENG) with the merits of light‐weight and high‐efficiency at low frequency, an energy harvesting device is designed to harvest undersea energy by bionic‐fin‐structure assisted with multilayer‐structured triboelectric nanogenerator (BFM‐TENG). The good design of geometry and structure enable BFM‐TENG to harvest energy efficiently by the driving of water‐flow from multidirections. Besides, based on the multiarea contact structure and ultrathin dielectric material, the BFM‐TENG could achieve a peak power density of 444 W m −3 under ideal test condition, which is about 1–2 orders of magnitude higher than that of previous work for harvesting wave energy. The findings not only provide a new in situ undersea energy harvesting method for undersea detectors to realize the real‐time, long‐term, and self‐powered undersea research, but also provide a potential strategy to achieve large‐scale undersea energy harvesting.