Piezoelectric BaTiO₃ microclusters and embossed ZnSnO₃ microspheres-based monolayer for highly-efficient and flexible composite generator

As a permanent power source for self-powered electronics, piezoelectric energy harvesters (PEHs), which convert waste mechanical energy into electrical energy, have attracted considerable interest. We herein developed a high-performance PEH by employing a piezoelectric BaTiO₃ microclusters (MCs) composite and a ZnSnO₃ microspheres (MSs)-based pressure concentrator. The piezoelectric composite film and an embossed pressure concentrator were fabricated by optimized bar-coating and unidirectional rubbing processes, respectively. The final energy device, fabricated by stacking a ZnSnO₃ MSs-based embossed pressure concentrator onto a BaTiO₃ MCs-based piezoelectric composite, harvested output signals of ~206 V and ~24 μA under an applied pressure of 0.27 MPa, which are significantly improved results compared to previously reported composite-type PEHs. Furthermore, multiphysics-based finite element analysis was performed to support the hypothesis of effective piezo-potential distribution by adopting the BaTiO₃ MCs embedded in polymeric matrix and attaching the ZnSnO₃ MSs-monolayer onto the piezoelectric composite. This technology represents a new approach with significant advantages for fabricating high-output composite-based PEHs.