Frequency modulated hybrid nanogenerator for efficient water wave energy harvesting

The energy crisis and environmental pollution are the two major challenges facing humanity, and harvesting energy from the ocean is a promising solution. In this paper, a triboelectric-electromagnetic-piezoelectric hybrid energy harvester (TEP-HEH) for low frequency wave energy harvesting is presented. With the introduction of the cantilever beam structure, the vibration frequency is converted from 0.2 Hz (simulated wave frequency) to 7.2 Hz, which greatly improves the energy harvesting performance of the electromagnetic generator (EMG) and the piezoelectric nanogenerator (PENG) modules. By broadening the frequency bandwidth of wave energy harvesting, a large power density of 5.73 W m−3 is obtained for the TEP-HEH. Besides, the output performance of TENG, EMG, and PENG modules is investigated and the connection mode of the three types of modules is discussed. The TEP-HEH can light up a commercial lighting bulb with a rated power of 5 W or power small electronics. This work provides an efficient solution for low frequency wave energy harvesting and the realization of the blue-energy dream.