A ferroelectric/ferroelastic energy harvester : Load impedance and frequency effects

Ferroelectric/ferroelastic switching, which can generate greater charge flows than piezoelectricity for the conversion of mechanical energy into electrical energy, has great potential for novel transducers. In this work, a stress-driven ferroelectric/ferroelastic energy harvester, exploiting internal bias fields in a partially poled ferroelectric, is explored. The harvester is tested and optimized for low-frequency applications, and the effects of electrical load impedance and operating frequency are studied. The device has a simple configuration and offers power density up to about 20 mW/cm³ of active material in the 1–20 Hz frequency range, which is a significant advance over piezoelectric transducers. Additionally, the results show that the energy output at a specific frequency can be optimized through appropriate choice of load impedance, and the optimized cycle works for over 10⁷ cycles at 20 Hz with only slight fatigue degradation, where the peak voltage decreases by 13% and an accompanying 24% drop in average power output. This provides a new perspective for energy harvesting to maximize energy conversion based on ferroelectric/ferroelastic switching with controllable performance. © 2023 Elsevier Ltd