Recent advances in spring-assisted triboelectric nanogenerators

Spring-assisted triboelectric nanogenerators (S-TENGs) have emerged as effective energy solutions to harvest low-frequency and low-amplitude vibration energy via resonance tuning, amplifying relative motion, and enhancing contact force between triboelectric layers. Unlike conventional TENGs, S-TENGs uniquely harness elastic resonance through integrated spring structures to efficiently harvest low-frequency and subtle mechanical vibrations that are otherwise difficult to convert into electricity, thereby enhancing overall energy conversion efficiency. Recent innovations in the field of triboelectric materials, electrode designs, and structures have enabled high-performance TENGs to be developed for sustainable green energy. This review highlights the pivotal role of spring elements in improving S-TENG performance and provides design insights for constructing robust, self-powered, and maintenance-free sensing platforms. Diverse architectures, including linear and multi-degree-of-freedom systems, as well as cantilever, tower, helical, magnetic, and composite designs, each engineered to optimize vibration response and maximize output performance, present possibilities for application in independent power sources. Hybrid triboelectric–electromagnetic integration, negative-stiffness mechanisms, and mechanical frequency regulation further extend the adaptability of S-TENGs to real-world conditions. Industrial equipment monitoring, wireless carbon dioxide (CO₂) sensing, omnidirectional vibration harvesting, and fault detection of the motors in unmanned aerial vehicles (UAV) indicate the versatility and practical impact of S-TENGs.