Octagonal‐Prism Phononic Crystal for Energy Harvesting

Piezoelectric energy harvesting (PEH) devices provide a self‐powered solution for microscale low‐power devices by converting ambient mechanical energy into electrical energy. In this work, a point‐defect phononic crystal (PnC) composed of octagonal prisms was designed based on phononic crystal theory, and its elastic wave energy localization and harvesting characteristics were systematically investigated through numerical simulations. The results demonstrated that tuning the geometric parameters, supercell size, and defect position significantly enhanced the displacement localization intensity of defect modes, thereby improving the energy harvesting efficiency. The proposed PnC‐based PEH system achieved a maximum output voltage and output power of 18.546 V and 3.76 mW, respectively. Compared with that of the PEH system without the PnC, the output power of the designed PEH system with PnC increased by 2686 times. This work provides a new design structure for high‐density PEH systems.