Enhanced electrical and energy storage performances of Fe, Sb co-doped BNBCTS ceramics synthesized via the solid-state combustion technique

In this study BNBCTS ceramics were co-doped with Fe and Sb to form (Bi (0.5) Na (0.5))0.93 (Ba0.945Ca0.055)(0.07)(Ti((0.9946- x))Sn-0.0054)(Fe0.5Sb0.5)xO(3) ceramics (denoted as BNBCTS-xFS) with various x content and were prepared via the solid-state combustion technique to enhance the electrical and energy storage performance. The effect of co- doping Fe and Sb on the phase formation, defect dipole, microstructure, electrical and energy storage properties of BNBCTS-xFS ceramics was studied. When x content increased from 0.0 to 0.030, the amount of the rhombohedral (R) phase decreased from 51 to 24 % while the tetragonal (T) phase increased from 49 to 76 %. The increased Fe and Sb content increased the defect dipole of singly/doubly charged oxygen-vacancies (V-O(center dot)/V-O(center dot center dot)) and caused more Ti4+ to transition to Ti3+, which caused the transition temperature of the ferroelectric phase to relaxor state (TF-R) in the ceramics to drop to below room temperature and it exhibited relaxor characteristics at room temperature. The ceramic with an x content of 0.010 had the largest grain size (3.06 mu m), excellence ferroelectric properties (P-r similar to 31.04 mu C/cm(2), Pm similar to 38.98 mu C/cm(2) and Ec similar to 18.28 kV/cm), the largest electro strain (similar to 0.175 %) and a large d(33)* of 350 pm/V. Moreover, when x = 0.020, the ergodic relaxor ceramic showed the smallest grain size (1.03 mu m), the lowest remanant polarization (P-r) of 4.52 mu C/cm(2) and the lowest coercive field (E-c) of 8.37 kV/cm, at an electric field of 60 kV/cm. More importantly, energy storage properties at the electric breakdown strength (E-b = 120 kV/cm) of the ceramics with an x content of 0.020 exhibited a recoverable energy storage density (W-rec) of 1.81 J/cm(3), a total energy storage density (W-total) of 2.95 J/cm(3) and an efficiency (t(i)) of 61.30%, with excellent thermal (similar to 25-150 degrees C) and frequency stability (similar to 1-100 Hz). This study provides new insights into the modulation of BNBCTS ceramics with Fe and Sb co-doping, which could effectively improve the electrical properties and energy storage properties of BNBCTS-xFS ceramics.