3D spring-based piezoelectric energy generator

Highlights: • A simple, fast, and cost-efficient approach is proposed to fabricate the high-performance 3D piezoelectric spring energy generator. • Commercial LED lamps and capacitors are able to be powered by the 3D piezoelectric spring. • Output performance was analyzed at different strains, speeds, frequencies, and resistances, confirming the possibility as a multifunctional sensor. • The proposed 3D piezoelectric springs hold the potential to replace the normal, commercial sprigs. Well-defined design and fabrication of piezoelectric energy generators are required for surrounding environment energy harvest, capable of providing sustainable, renewable energy for future life. Herein, we present a 3D piezoelectric spring in a sandwich structure mainly constituted of a flexible Al electrode, electrospun PVDF film, and a Pt electrode, where the inside commercial springs act as a 3D structural foundation. The resulting 3D piezoelectric spring exhibits its potential as a multifunctional sensor to detect strain, speed, frequency, and resistance. It is further bridged with LED/capacitor by rectifier for illumination and charging, enabling highly efficient environment energy harvest and storage. The parallel connection of three piezoelectric springs exhibits an output voltage of 7.2 V and output current of 300 nA for 21 MΩ resistance, which are three times of single piezoelectric spring, demonstrating the possibility of scale‐up. This work provides an effective strategy for 3D piezoelectric spring fabrication, and new insights for spring-based piezoelectric energy generators, devoting to energy harvesting technology.