K1/2Bi1/2TiO3-based temperature stable dielectrics for high voltage/temperature applications

0.5KBT-(0.5-x) BF-xLMN with x = 0, 0.04, 0.06, 0.08 and 0.10 ceramics were fabricated using a conventional solid-state reaction method. All samples exhibited a single pseudocubic perovskite phase with minor levels of Bi4Ti3O12 as a secondary phase. The average grain size decreased slightly with x from ~ 2.2 to 1.8 µm and Impedance Spectroscopy at elevated temperatures showed the ceramics to be electrically homogeneous with the insulation resistance of x > 0 all exceeding x = 0 with x = 0.04 displaying the highest activation energy for conduction at ~ 1.1 eV. The permittivity (~1500 at 100 °C) was frequencydependent, implying relaxor behavior, and exhibited a temperature stable plateau between ~100-250 oC. 0.5KBT- 0.46BF-0.04LMN had the highest Epulse and recoverable energy density, Wrec of 130 kV cm-1 and 1.14 J cm-3, respectively, accompanied by low strain (<0.1%). The combination of high Epulse, a temperature stable plateau in permittivity, exceptionally low strain and large Wrec, suggest these compositions have potential for use in MLCCs for high voltage/temperature applications in power electronics.