Electromechanical Performance and Figure of Merit Optimization for Flexible Lead-Free PDMS-BaTiO 3 Piezocomposites

In the modern era of the Internet of Things, the potential role of flexible piezoelectric generators (PEG) reflects the rapid increase in self-powered devices and wearable technologies. In this study, a casting process to elaborate the polydimethylsiloxane (PDMS)/barium titanate (BaTiO3) composite has been presented. The addition of 15 wt % BaTiO3 microparticles into the PDMS polymer greatly enhances the piezoelectric coefficient (d(31) = 24 pC N-1), leading to an increased output voltage of approximately 4 V under finger tapping force. The proposed flexible microgenerator yielded an excellent piezoelectric figure of merit (FoM(31) = 13.1 x 10(-12) m(2) N-1), significantly enhancing successfully the energy-harvesting performance (power density of 35 nW/cm(2)). Furthermore, the fabricated lead-free PEG exhibited an excellent flexibility figure of merit (fFoM) due to the low young modulus values (Maximum E = 3.4 MPa). These results indicate efficient energy conversion and demonstrate a favorable balance between the flexibility and piezoelectric properties of the composite, highlighting its potential for a wide range of applications in self-powered wearable sensors able to collect different human motions in applications such as gesture tracking and finger motion detection.