Omni-directional harvesting of ocean wave energy using arch-shaped double-layered direct-current triboelectric nanogenerator

Ocean wave energy represents an essential source of green, low-cost, and renewable clean energy. Triboelectric nanogenerator (TENG) technology has demonstrated its potential for use in ocean wave energy harvesting. However, most TENG designs face challenges that include complex energy management and storage requirements, along with TENG output performance degradation at low ocean frequencies. Here, we present a pulsed arch-shaped double-layered direct-current TENG (aDC-TENG) that captures low-frequency ocean wave energy efficiently. Because of its arched structure, the system reduces operational resistance and converts ultralow vibrations from ocean waves at frequencies as low as 0.1 Hz into electrical energy. By using the electrostatic breakdown that is designed to occur between synergistically distributed electrodes, a unidirectional current loop is formed that generates unidirectional peak pulse currents as high as 23.5 mu A at 0.1 Hz. The integrated aDCTENG array, which is placed on the bottom of the buoy alongside small spheres, achieves automatic contact and separation through the coupled motion of the spheres and the ocean waves, thus enabling omni-directional harvesting of the energy from the ocean waves. The aDC-TENG was operated successfully in Sanya Bay and demonstrated remarkable environmental adaptability. Our research results have opened up a path toward the development of more efficient and convenient techniques for collection of the ocean wave energy required to drive a variety of sensors and other electronic devices.