3D Printing of Flexible BaTiO₃/Polydimethylsiloxane Piezocomposite with Aligned Particles for Enhanced Energy Harvesting

With the rapid development of human–machine interactions and artificial intelligence, the demand for wearable electronic devices is increasing uncontrollably all over the world; however, an unsustainable power supply for such sensors continues to restrict their applications. In the present work, piezoelectric barium titanate (BaTiO₃) ceramic powder with excellent properties was prepared from milled precursors through a solid-state reaction. To fabricate a flexible device, the as-prepared BaTiO₃ powder was mixed with polydimethylsiloxane (PDMS) polymer. The BaTiO₃/PDMS ink with excellent rheological properties was extruded smoothly by direct ink writing technology (DIW). BaTiO₃ particles were aligned due to the shear stress effect during the printing process. Subsequently, the as-printed composite was assembled into a sandwich-type device for effective energy harvesting. It was observed that the maximum output voltage and current of this device reached 68 V and 720 nA, respectively, for a BaTiO₃ content of 6 vol %. Therefore, the material extrusion-based three-dimensional (3D) printing technique can be used to prepare flexible piezoelectric composites for efficient energy harvesting.