Dielectric, piezoelectric and electromechanical optimization properties of polyurethane/lead zirconate titanate composites for mechanical energy harvesting applications

Lead zirconate titanate (PZT) is the most common piezoelectric ceramic and exhibits excellent electromechanical conversion properties. But in order to make it more adaptable for energy harvesting applications, we resort to ceramic/polymer composites because of their excellent and tailorable properties. The advantages of this type of composite are high coupling factors due to PZT, mechanical flexibility (PU) and wide bandwidth. In this work, we studied the mechanical and electrical characteristics of this composite, as well as their behavior as a function of the percentage of PZT (by volume). Forth more, we followed the impact of this parameter on the collected energies, as well as others like frequency and resistance. The harvested power significantly increases with increasing PZT, achieving a power value up to 13.4 and 420 nW for PU/PZT 60% and PU/PZT 70%, respectively. In conclusion, composite piezoelectric films have great potential from an energy density viewpoint and could represent interesting candidates for energy harvesting applications.