Enhanced transduction coefficient and thermal stability of 0.75BiFeO3-0.25BaTiO3 ceramics for high temperature piezoelectric energy harvesters applications

Abstract

Owing to the coexistence of high depolarization temperature of 500 °C and good piezoelectric properties, 0.75BiFeO3-0.25BaTiO3-0.5mol%MnO2 (BFBTMn) ceramics show potential energy harvesting applications at elevated temperature. Chemical modifications are usually difficult to improve transduction coefficient (d33×g33) due to the opposite directions of d33 and g33. Herein, the BFBTMn ceramic powders with different average grain sizes of 500 (S1), 700 (S2) and 800 (S3) nm were mixed together for ceramics preparation. This method promotes the grain size, relative density and rhombohedral phase volume fraction of BFBTMn ceramics, leading to the much improved piezoelectric transduction coefficient and its thermal stability. The transduction coefficient of ceramics with optimized weight ratio (1S1:2S2:1S3) reaches up to 4644 × 10−15 m2/N, about 51% higher than those without mixed powder and at least 60% higher than those reported in the literatures, while its degradation from room temperature to 500 °C is about 15%, much smaller than that (30%) of ceramics without mixed powders. These investigations pave a new way to tailor the transduction coefficient and its thermal stability of BF-BT piezoelectric ceramics for high temperature energy harvesting devices.