Non-resonant electromechanical energy harvesting using inter-ferroelectric phase transitions

Abstract

Non-resonant electromechanical energy harvesting is demonstrated under low frequency excitation (<50 Hz) using [110]C-poled lead indium niobate-lead magnesium niobate-lead titanate relaxor ferroelectric single crystals with compositions near the morphotropic phase boundary. The efficiency of power generation at the stress-induced phase transition between domain-engineered rhombohedral and orthorhombic ferroelectric states is as much as four times greater than is obtained in the linear piezoelectric regime under identical measurement conditions but during loading below the coercive stress of the phase change. The phase transition mode of electromechanical transduction holds potential for non-resonant energy harvesting from low-frequency vibrations and does not require mechanical frequency up-conversion.

Anisotropy free energy contribution of the ferroelectric domain dynamics in PMN‐PT and PIN‐PMN‐PT relaxor ferroelectrics

“…As a demonstration purpose, the measured $${C_P}$$ for PIN‐PMN‐32PT is shown in Figure 7A (solid line). It was determined from the MDSC signal, as discussed in the experimental section, capable to separate the phase transition contributions from the energy associated with relaxor phenomena (such as polar nanoscale regions), typically observed as a hump in the heat capacity data 54–56 . Phase transitions were observed at $${T_{RT}} = 386 K$$ and $${T_{PF}} = {T_0} = 435 $$.…”

“…Historically, α 123 has been considered as part of the sixth‐, eighth‐, and tenth‐order Landau polynomials 58–61 . For example, it was incorporated into the Landau polynomial to stabilize the lowtemperature F R ‐phase in barium titanate 54,59 . However, considering the free energy expression in Equation (), if α 112 is temperature dependent near a low‐temperature interferroelectric phase change, α 123 will have minimal contribution.…”

Non-Resonant Magnetoelectric Energy Harvesting Utilizing Phase Transformation in Relaxor Ferroelectric Single Crystals

“…High energy and power conversion is observed at a stress-induced inter-ferroelectric phase transformation in a mechanically constrained relaxor ferroelectric single crystal. Although thermal energy harvesting was not demonstrated here, it is an inherent property of the domain engineered crystal and is expected to occur, according to our previous harvesters operating on the phase transition transduction principle [7][8][9]. The harvester described in this work can thus be utilized for broadband multi-domain harvesting of magnetic, mechanical, and thermal energy with high power density per cycle.…”

“…Moreover, the device is capable of low frequency energy conversion in the Hertz region and is not frequency-limited up to several kHz by the piezoelectric crystal-load impedance [8]. This device is also capable of converting variations in environmental temperature to a usable electrical output [9] and therefore can be considered a dual-domain harvester.…”

“…This electro-mechanical energy conversion was manifested during a ferroelectric-ferroelectric phase transformation in [011] cut domain engineered perovskite lead titanate-based relaxor ferroelectric single crystals with compositions near the morphotropic phase boundary (MPB) [7][8][9]. It was found that under mechanical pre-stress, a relatively small oscillatory stress or electric field drives the material reversibly between the ferroelectric rhombohedral (F R ) and ferroelectric orthorhombic (F O ) states with a remarkably high polarization and strain jump induced at room temperature.…”