High energy storage and thermal stability under low electric field in Bi0.5Na0.5TiO3-modified BaTiO3-Bi(Zn0.25Ta0.5)O3 ceramics

Dielectric energy storage capacitors have been comprehensively investigated for application in advanced electronic systems. Compared to other types of ceramic capacitors, BaTiO3-BiMeO3 lead-free composite relaxor ferroelectric ceramics (where Me represents trivalent or trivalent composite ion) are excellent dielectric energy storage candidates in pulsed power fields. However, the properties of most existing BT-based energy storage ceramics are not satisfactory in some practical aspects, and feasible guidance on efficient composting material systems with large recoverable energy storage density (W-rec) for ultralow electric fields is lacking. Herein, for the first time, lead-free relaxor ferroelectric (1-x)[0.9BaTiO(3)-0.1Bi(Zn0.25Ta0.5)O-3]-xBi(0.5)Na(0.5)TiO(3) ceramics with x = 0, 0.1, 0.2, 0.3, and 0.4 were synthesized via composite strategy using the traditional solid-state process. The used strategy combined the complementary advantages of both BT-BZT and BNT to greatly increase the saturation polarization (P-s) and shift the stable temperature range of permittivity to high-temperature region, achieving higher energy storage density and improved temperature stability. Optimum energy storage performances with a high W-rec of 4.18 J/cm(3) and comparatively high eta of 84.01% were simultaneously achieved in the relatively low electric field of 230 kV/cm. Moreover, the ceramic obtained at x = 0.3 showed excellent temperature stability with the change rate of W-rec < 5% and eta < 6% throughout a broad temperature range (20 ?C ~ 170 ?C). This ceramic (x = 0.3) simultaneously possesses superior pulse performance, exhibiting the t(0.9) of 232 ns and W-dis of 2.51 J/cm(3). Overall, the employed composite strategy design is effective for obtaining energy storage capacitors with excellent performance for future advanced pulsed power devices.