3D vertically aligned microchannel structure to enhance piezoelectric energy harvesting performance of PZT/PVDF&CNTs piezoelectric composites

Piezoelectric energy harvesters (PEHs) have attracted significant attention with the ability of converting mechanical energy into electrical energy and power the self-powered microelectronic components. Generally, material's superior energy harvesting performance is closely related to its high transduction coefficient (d33×g33), which is dependent on higher piezoelectric coefficient d33 and lower dielectric constant εr of materials. However, the high d33 and low εr are difficult to be simultaneously achieved in piezoelectric ceramics. Herein, lead zirconate titanate (PZT) based piezoelectric composites with vertically aligned microchannel structure are constructed by phase-inversion method. The polyvinylidene fluoride (PVDF) and carbon nanotubes (CNTs) are mixed as fillers to fabricate PZT/PVDF&CNTs composites. The unique structure and uniformly distributed CNTs network enhance the polarization and thus improve the d33. The PVDF filler effectively reduce the εr. As a consequence, the excellent piezoelectric coefficient (d33 = 595 pC/N) and relatively low dielectric constant (εr = 1603) were obtained in PZT/PVDF&CNTs composites, which generated an ultra-high d33×g33 of 24,942 × 10−15 m2/N. Therefore, the PZT/PVDF&CNTs piezoelectric composites achieve excellent energy harvesting performance (output voltage: 66 V, short current: 39.22 μA, and power density: 1.25 μW/mm2). Our strategy effectively boosts the performance of piezoelectric-polymer composites, which has certain guiding significance for design of energy harvesters.