Energy harvesting by exploiting the enhanced flexoelectric-like response of reduced (Na0.5Bi0.5)0.92Ba0.08TiO3 ceramics

By exploiting the flexoelectric effect, flexoelectric piezoelectric composites (or piezoelectric metamaterials) with a high-temperature-stable piezoelectric response can be designed, but the practical applications of these materials have rarely been explored. We show that after the reduction, the flexoelectric (or flexoelectric-like) response of Na0.5Bi0.5TiO3-based ferroelectric ceramics can be enhanced by 100 times, and the materials exhibit a high apparent piezoelectric response even at a temperature above the depolarization temperature (Td) of the materials. The performance of the reduced ceramics as an energy harvester was evaluated, especially at a temperature above Td. We found that the chemical reduction enhanced the output power of the ceramics above Td by more than 100 times. Although the performance of the flexoelectric energy harvester is inferior to that of conventional piezoelectric harvester below Td, flexoelectric harvester based on the reduced NBBT8 ceramics provides an approach to harvest the mechanical energy above Td.