Hybridized triboelectric-electromagnetic nanogenerators for efficient harvesting of wave energy for self-powered ocean buoy

Triboelectric nanogenerators (TENGs) have been widely used in energy harvesting from low-frequency, irregular motions due to their unique characteristics and excellent electromechanical conversion efficiency. Harvesting ocean energy to build a marine Internet of Things (MIoTs) has become an important research field for TENGs. However, the output power density of TENGs must be further enhanced for promoting their practical applications, by effective means such as the coupling of TENGs and electromagnetic generators (EMGs). Herein, we report a triboelectric-electromagnetic hybrid nanogenerator (TEH-NG) for self-powered ocean buoy to harvest water wave energy efficiently for the first time. The buoy consists of a self-engineered wave energy converter for converting wave energy into simple turbomachinery energy through the pressure difference created by the relative motion, and a TEH-NG for converting the turbomachinery energy into electrical energy. The TENG delivers an average output power of 3.40 mW (with power density of 141.7 W m- 3), and the EMG achieves an average power of 0.04 W (with power density of 400.0 W m-3). The excellent performance of the TEH-NG makes it a potential candidate for constructing the MIoTs to achieve distributed marine environmental monitoring networks.