Improved T_c and ferroelectric fatigue characteristics of BaTiO₃-rich (1 − x) BaTiO₃-(x) Bi_0.5K_0.5TiO₃ lead-free electroceramics

The (1 − x) BaTiO₃-(x) Bi_0.5K_0.5TiO₃ (x = 0.02,0.04,0.06,0.08,0.1 mol.%) lead-free electroceramic system was prepared by a solid-state reaction method, to improve the Curie temperature (T_c) and ferroelectric fatigue nature of BaTiO₃ ceramics. The structural analysis by X-ray diffraction and Raman spectra evidences the formation of tetragonal lattice symmetries with an increase of c/a tetragonality ratio due to the addition of Bi_0.5K_0.5TiO₃ ceramics into BaTiO₃ along with the existence of Raman active modes corresponding to tetragonal phase. Dense microstructure and lattice strain with diffuse phase transition (DPT) are observed to show enhanced bulk density and improved ferroelectric fatigue characteristics up to 10⁶ cycles. The composition x = 0.08 mol.% i.e., BTKT-4 reveals the Curie temperature ~ 172 °C which is quite larger than the pure BaTiO₃ (T_C ~ 120 °C) ceramic with enhanced energy storage efficiency (ɳ ~ 48.12%) and fatigue-free polarization response upto 10⁶ cycles indicating a promising novel environmentally friendly, lead-free ceramic candidate for high-temperature applications.