Efficient Harvesting of Irregular and Low-Frequency Mechanical Energy via Hybridized Electromagnetic-Triboelectric...

The rapid expansion of the Internet of Things (IoT) and wearable electronics necessitates sustainable power sources to replace the limited electrochemical battery. While mechanical energy harvesting offers a promising solution, traditional harvesters face challenges of irregular and low-frequency environmental sources. This review presents the hybridized electromagnetic-triboelectric nanogenerator (HE-TENG) as an effective strategy to overcome individual limitations of the electromagnetic generator (EMG) and triboelectric nanogenerator (TENG). By integrating the high-current characteristics of the EMG with the high-voltage, low-frequency efficiency of the TENG, the HE-TENG achieves a complementary broadband frequency response and enhanced energy conversion efficiency. The fundamental working principles, theoretical models, and impedance matching requirements of both mechanisms are analyzed to elucidate their synergistic coupling. Furthermore, recent advances in structural design are categorized based on diverse mechanical energy sources, including wind, water waves, and hydrokinetic flows. The analysis highlights specific hybridization strategies, such as bio-inspired mechanisms and variable transmission systems, to optimize performance under stochastic environmental conditions.