Improved electric energy storage properties of BT-SBT lead-free ceramics incorporating with A-site substitution with Na & Bi ions and liquid sintering generated by Na0.5Bi0.5TiO3

Abstract Due to the merits of high safety and easy preparation, dielectric ceramics have become key engineering materials for capacitors. Within this article, different contents of Na0.5Bi0.5TiO3 were introduced into Ba0.65Sr0.245Bi0.07TiO3 relaxor ferroelectric ceramics in order to increase the disorder degree of A-site ions in perovskite structure and modify the relaxation, which could generate liquid sintering promoting densification, then finally enhancing the dielectric energy store performance of ceramics. The research results show that all the bulk samples prepared through traditional processing route are exhibiting pseudocubic perovskite structure, and their surfaces are with Na0.5Bi0.5TiO3 (NBT)-rich phase formed during densification due to a relatively low sintering temperature of NBT. The relaxation coefficient of BT-SBT-0.01NBT ceramic is 1.8. Because of the existence of liquid phase formation during sintering, the dielectric breakdown strength (BDS) of BT-SBT-0.01NBT ceramic is increased to 230 kV/cm, and the recoverable energy density (Wrec) reached 2.22 J/cm3. The introduction of NBT can hence enhance the relaxation and BDS, finally elevate the energy storage performances.