Lead-free piezoelectric polymer-ceramic films for sustainable energy harvesting

The rapid expansion of flexible electronics, soft robotics, and biomedical devices has driven growing interest in the development of flexible and sustainable energy-harvesting systems. Polymer–ceramic piezoelectric composites, which combine the high breakdown strength and mechanical flexibility of polymers with the outstanding dielectric and piezoelectric response of ferroelectric ceramics, have therefore emerged as promising candidates for next-generation energy harvesting materials. In this work, composite films consisting of a PVDF-based matrix filled with 30 vol% BaTiO 3 (BT) particles were prepared using several fabrication routes: a one-step method based on hot pressing (HP), and different two-step approaches: namely, melt blending (MB), solvent casting (SC) and microwave irradiation and mixing (MW), all followed by a final hot pressing step. MW is here proposed for the first time as an innovative, highly eco-friendly and energy-efficient approach aimed at boosting the preparation of this class of composite materials, while maintaining good overall performance. The resulting materials were systematically characterized with respect to their morphology, thermal properties, mechanical behaviour, and dielectric and piezoelectric performance. Comparative analysis reveals how processing history may influence BT dispersion, polymer thermal behaviour, and overall electromechanical response. This study identifies the relative advantages and limitations of each preparation route and highlights the most promising strategies for scalable fabrication of flexible, high-efficiency piezoactive composites for next-generation energy-harvesting applications.