3D Printing Modulated Polyvinylidene Fluoride Arrays for Enhanced Output of Piezoelectric Energy Harvesters

Compared with traditional two-dimensional piezoelectric energy harvesters (PEHs), the construction of three-dimensional (3D) structures can couple piezoelectric coefficients and multidimensional flexibility, enabling more sensitive sensing and efficient energy harvesting. However, the understanding of the underlying mechanism of how the structure design of the PEH contributes to its piezoelectric properties remains superficial so far. Herein, we propose theoretical simulation combined with a fused deposition modeling (FDM) 3D printing technique to construct polyvinylidene fluoride (PVDF) array PEHs with different annular microcell (triangular, circular, and square ring) structures. The theoretical simulation results show that reducing the force area of the microcell can effectively amplify the local strain, resulting in a significant increase in the piezoelectric output of PVDF array PEHs. Consistent with the simulation results, the triangular ring array PVDF PEH with a small force-bearing area shows the highest piezoelectric output voltage of 15.6 V, which can quickly charge a 1 μF capacitor to 5.5 V within 5 min. This work provides guidance for architecting 3D PEH with efficient force-electric conversion structures for future green energy storage and self-powered systems.