Realization of a Sustainable Charging Power Source by In Situ Low‐Frequency Water Wave Energy Harvesting with a Coaxial Triboelectric–Electromagnetic Hybrid Generator

Long‐term ocean monitoring and sensing remain a great challenge for the lack of sustainable power sources. Herein, a coaxial hybrid energy harvester (CH‐EH) consisting of triboelectric nanogenerators (TENGs) and electromagnetic generators (EMGs) is fabricated to charge lithium (Li)‐ion batteries through in situ water wave energy harvesting, enabling sustainable power supply. Triggered by mechanical motions, the TENGs and EMGs (connected in parallel) of CH‐EH move in the same phase at the same frequency through a shared‐bearing swing arm and generate high‐voltage, high‐current outputs after being rectified separately. At a wave frequency of 0.8 Hz and a wave height of 20 cm, the peak voltage and current are 194.09 V and 2.593 mA, respectively. After charging a 13.2 mF capacitor for approximately 7.5 min, the CH‐EH array successfully drives a thermometer with a Bluetooth module. Moreover, after charging a 22 mF capacitor for 33 min, the CH‐EH array successfully drives a radio‐frequency module to realize wireless transmission. Furthermore, a 35 mAh lithium battery is successfully charged by the designed circuit, and the fully charged lithium battery continuously powers a thermohygrometer for 13 h. Hence, the as‐designed CH‐EH has broad application prospects in long‐term ocean sensing and monitoring.