Exploiting ferroelectric and ferroelastic effects in piezoelectric energy harvesting: theoretical studies and parameter optimization

Abstract

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.

Investigation of mechanical energy harvesting cycles using ferroelectric/ferroelastic switching

“…Thus, a combination of stress and electric field is normally needed to achieve stable cycles. Some theoretical designs of ferroelectric energy harvesters [54,55] solved the problem of cycle stability by using a bias electrical field, which breaks the symmetry of the unpoled state, and allows the action of stresses to drive a repolarization process that is effectively "directed" by the bias field.…”

“…Nonlinear ferroelectric/ferroelastic switching induced by electric field and stress offers the potential for high power density in energy harvesting [54][55][56][57][58]. Several theoretical high-performance ferroelectric energy harvesters have been developed in recent years including a working cycle [59] in which a polycrystalline ferroelectric material is partially depolarized with stress, and then repolarized with combined electromechanical loading and an external bias field.…”

“…This energy harvesting system has the advantage that it employs standard bulk ferroelectrics and has the potential to be realized in various kinds of structural forms, though there is complexity in controlling the external bias voltage. Warkentin et al [54] further analysed and optimised this working cycle using a ferroelectric switching model.…”

Hybrid modeling of viscoelastic and switching–induced heating in ferroelectrics

“…Simulations are based on a multi-scale constitutive framework of polycrystalline ferroelectrics in connection with the so-called condensed method (CM). These theoretical considerations will further be applied to the design and optimization of cyclic processes in ferroelectric energy harvesters, exhibiting a large electrical output by exploiting the irreversible effects [1].…”

Multiscale modeling of ferroelectrics with stochastic grain size distribution

“…In the recent past, all these aspects have been included in modeling approaches of ferroelectric, ferromagnetic, and multiferroic materials, based on the so-called condensed method (CM) (Behlen et al, 2021; Lange and Ricoeur, 2015, 2016; Ricoeur and Lange, 2019; Uckermann et al, 2018; Warkentin and Ricoeur, 2020). This semi-analytical approach comprises homogenization within a multiphysical framework and scale–bridging interactions in a simple but robust and thermodynamically and electromechanically consistent manner.…”