While piezoelectric energy harvesting typically focuses on converting mechanical into electrical energy on the basis of the linear reversible piezoelectric effect, the potential of exploiting the non-linear ferroelectric effect is investigated theoretically in this paper. Due to its dissipative nature, domain switching, on the one hand, is basically avoided in order to prevent mechanical energy from being converted into heat. However, the electrical output, on the other hand, is augmented due to the increased change of electric displacement. In view of these conflicting issues, one main objective in ferroelectric energy harvesting thus is to identify mechanical and electrical process parameters providing appropriate figures of merit. Being an efficient approach to numerically simulate multiphysical polycrystalline material behavior, the so-called condensed method is taken as a basis for the investigation and finally optimization of controllable parameters of ferroelectric energy harvesting cycles. A first idea of a technical implementation taken from literature is considered as cycle of reference, constituting the starting point of the present study, being focused on material aspects rather than on harvesting devices. Different quality assessing parameters are introduced, taking into account general aspects of harvesting efficiency as well as the ratio of irreversible switching-related to reversible piezoelectric contributions. Residual stresses are likewise predicted to give an idea of reliability and the risk of fracture. Two types of cycles and associated optimal process parameters are finally presented.

A new ferroelectric energy harvesting concept is investigated theoretically, based on a thermo-electromechanical multiscale constitutive framework in connection with the so-called condensed method. Taking advantage of comparatively large changes of strain and polarization due to domain switching, the electric output is higher compared to what is commonly known as piezoelectric energy harvesting. Dissipative self-heating and augmented damage accumulation, on the other hand, may impede the operability of the harvesting device, in particular if tensile stress is required for depolarization, as suggested by recent works. The new harvesting cycle thus dispenses with tensile stresses and instead exploits the potential of existing residual stresses. It is further investigated to which extent a bias field, commonly applied to support repolarization as an important stage of the cycle, can be omitted, saving considerable effort on the technical implementation. Process parameters are obtained from various simulations by pareto-ptimization, considering, inter alia, the effect of ambient temperature.