Highly adaptive and broadband triboelectric energy harvester with stretching silicone rubber strip for variable harmonic frequency vibration

An enormous number of wireless sensing nodes (WSNs) are of great significance for the Internet of Things (IoT). It is tremendously prospective to realize the in-situ power supply of WSNs by harvesting unutilized mechanical vibration energy. A harmonic silicone rubber triboelectric nanogenerator (HSR-TENG) is developed focusing on ubiquitous constant working frequency machinery. The unique design of the strip serving as a flexible resonator realizes both soft contact and high and broadband output. The significant factors influencing the 1^st-order vibration mode of the strip are developed for realizing the harmonic frequency adaptation to external vibration. The surface treatment of the strip improves the output performance of HSR-TENG by 49.1% as well as eliminates the adhesion effect. The HSR-TENG is able to achieve a voltage output bandwidth of 19 Hz under a vibration strength of 3.0, showing its broadband capability. The peak power density of 153.9 W/m³ is achieved and 12 × 0.5 W light-emitting diodes (LEDs) are successfully illuminated by the HSR-TENG. It can continuously power a temperature sensor by harvesting the actual compressor vibration energy. In brief, the HSR-TENG provides a promising way for constant frequency vibration energy harvesting, so as to achieve in-situ power supply for the WSNs in the vicinity.