Double‐Pendulum Bearing‐Joint Triboelectric Nanogenerator for Efficient Low‐Frequency Ocean Wave Energy Harvesting

ABSTRACT Marine Internet of Things (IoT) systems require reliable self‐powered sensor nodes for long‐term ocean monitoring. Triboelectric nanogenerators (TENGs) provide a promising solution for harvesting irregular ocean wave energy, but the low frequency, small amplitude, and randomness of ocean waves significantly limit the performance of conventional TENG designs. Here, a double‐pendulum wave energy harvester integrating bearing‐joint triboelectric nanogenerators is proposed. The double‐pendulum structure effectively amplifies low‐frequency wave motion and directly converts rotational motion into electrical output. Not only does one single joint generation unit deliver an average output power of 1.16 mW, but it also achieves notable improvements in peak and average power density among bearing‐type TENGs, reaching 52.46 and 17.95 W·m −3 , respectively. The architecture exhibits rapid capacitor charging and excellent durability under simulated ocean wave conditions, enabling the operation of multiple electronic devices without external power. This strategy provides a promising route toward low‐maintenance, long‐lasting power sources for self‐powered Marine IoT systems in complex ocean environments.