Giant power output in lead-free ferroelectrics by shock-induced phase transition

The force-electric effect in ferroelectrics is characterized by the release of bound charge during pressure/shock-induced depolarization. In contrast to other electrical energy storage systems, the charge-storage/release by the force-electric effect of ferroelectrics is determined by polarization switching or polar-nonpolar phase transition. This offers a further set of options for materials design in the realm of energy conversion, especially for the high power density applications. Here, we report that a ferroelectric ceramic, Na0.5Bi0.5TiO₃ (NBT), can generate a high power output (3.04×10⁸0.16em0exW/kg) under shock compression, which is one of the highest values achieved by the force-electric effect. The in situ synchrotron x-ray diffraction studies reveal that this power output mainly arises from a polar-nonpolar phase transition (rhombohedral-orthorhombic). First-principles calculations show that this is a first-order phase transition that undergoes two-step structure changes. These results extend the application of the force-electric effect and are a key step in understanding the phase transition behaviors of NBT under high pressure.