Improved relaxor ferroelectrics and energy storage performance of polycrystalline Ba0.95Sr0.05Ti2O5 ceramics modified with La dopants.

Lead-free relaxor ferroelectrics are useful in energy storage applications. In particular, BaTi 2 O 5 -based dielectric materials may have great potential for such applications. In this study, polycrystalline Ba 0.95 Sr 0.05 Ti 2 O 5 - x La (BST2- x La) ceramics were synthesized using a standard solid-state reaction method with as-prepared nanoparticles prepared via a modified Pechini polymeric precursor method. The structural and electrical properties of the BST2- x La ceramics were systematically investigated using a series of measurements. The phase analysis results confirm that La3+ is a donor dopant that replaced Ba2+ sites in the structure, which results in a decrease in oxygen vacancies to maintain charge neutrality. The intrinsic electronic conduction mechanism for electrical conductivity was evaluated from the fitted activation energy based on the Arrhenius equation. The relaxor ferroelectric behaviour and energy storage density and efficiency are improved by the addition of a small amount of lanthanum (<3.6 mol%) because of the charge and ionic radius mismatch in the structure. These results suggest that lanthanum can effectively optimise the relaxor ferroelectrics of BST2- x La ceramics, which have promising potential as energy storage materials. • Pure monoclinic-phase polycrystalline BST2- x La ceramics were synthesized. • La3+ acted as a donor dopant in the structure. • Mechanism of intrinsic electronic conduction in the ceramics was deduced. • La3+ could optimise the relaxor ferroelectric properties of BST2- x La ceramics. • The energy storage density and efficiency were improved at small values of x. [ABSTRACT FROM AUTHOR]