Improvements of depolarization temperature, piezoelectric and energy harvesting properties of BNT-based ceramics by doping an interstitial dopant

•We fabricated the BNBT6-B2O3 ceramics by a simple solid-state reaction method.•We report an alternative way to increase Td by using a boron oxide (B2O3) additive.•The 1 wt% B2O3 ceramic had high Pr = 23.67 µC/cm2 and Ec = 37.51 kV/cm.•Large d33, g33 and figure of merit (FoM) were also found for 1 wt% B2O3 ceramic. [Display omitted] An important problem of many BNT-based perovskite piezoelectric materials for real applications is to increase and/or to disappear the depolarization temperature (Td) as well as to achieve high piezoelectric properties. Many previous works, through various techniques, have tried to shift up the Td and also enhance piezoelectric properties. In the present work, we report an alternative way to increase the Td by using a boron oxide (B2O3) additive, where the boron ion in B2O3 is an interstitial dopant. The increase of Td is proposed to relate with an internal stress formation in the ceramic, due to the doping effect. Furthermore, improvements of remanent polarization (Pr), piezoelectric properties, loss tangent value and energy harvesting performance of the ceramics are also enhanced for the doped samples.