Flexible Piezoelectric Energy Harvester with Extremely High Power Generation Capability by Sandwich Structure Design Strategy

In order to achieve a high-performance flexible piezoelectric energy harvester (FPEH), a unique sandwich structure, that is, a PVDF film filled with FeTiNbO₆ (FTN) semiconductor particles as an intermediate layer and a pure PVDF film as an upper and lower barrier layer, has been designed, and the corresponding PVDF-FTN/PVDFx-PVDF (P-FTNx-P) compact composite has been prepared by hot-pressing technology. The special sandwich structure combined with the introduction of FTN particles is beneficial to enhance the interfacial polarization and the content of the electroactive phase in PVDF. Together with the maximum piezoelectric voltage coefficient and the moderate Young's modulus, the P-FTN15%-P FPEH exhibited the optimal energy-harvesting performance with a high power density of 110 μW/cm³ and a large charge density of 75 μC/m² in cantilever mode. The outstanding design in this work is expected to provide a new way for the development of high-performance FPEH materials.