Evaluation of (Na1/2Bi1/2)TiO3/PVDF Piezocomposites for mechanical energy harvesting

Abstract

This paper demonstrates the energy harvesting characteristics of 0–3 x(Na1/2Bi1/2)TiO3/(1-x)PVDF; 0 ≤ x (volume fraction) ≤ 0.30 composites employing the drop weight impact method. The X-ray diffraction method was adopted for ascertaining the formations of (Na1/2Bi1/2)TiO3 ceramic and (Na1/2Bi1/2)TiO3/PVDF composites. The values of bulk density, apparent porosity, free dielectric constant, piezoelectric coefficient (d33), figure of merit (FoM), and Shore D hardness were found to increase, whereas the value of tanδ first decreases up to x = 0.025 and then increases upon increasing x. Also, the value of the piezoelectric voltage constant (g33) increases up till x = 0.25 and it drops a little for x = 0.30. A remarkable increment in the contact voltage (from 7.71 V to 15.23 V for x = 0.30) with increasing impact height (h = 6–21 cm) and (from 5.37 V to 15.23 V for h = 21 cm) with increasing x was observed. The small values of water absorption (<0.099 wt%), apparent porosity (<2%), tanδ (∼10−2 at 1 kHz), and higher values of d33, g33, FoM, Shore D hardness, power output (Pdc = 2.32 μW using 47 kΩ and C = 100 pF for x = 0.30) as well as improved voltage responses, prefigure the possibility of current composite system, a better lead-free alternative for energy harvesting, piezo-detection/sensing and structural health monitoring technologies.