High Energy Storage and Excellent Thermal Stability in Ternary (1−x)[0.94(Bi_0.5Na_0.5)TiO₃‐0.06BaTiO₃]‐xCa(Mg_1/3Nb_2/3)O₃ Lead‐Free Ferroelectric Ceramics

Abstract

In this work, a new type of ternary lead‐free ferroelectric ceramics (1−x)[0.94(Bi0.5Na0.5)TiO3‐0.06BaTiO3]‐xCa(Mg1/3Nb2/3)O3 is synthesized by traditional solid‐state reaction method (x = 0.02, 0.04, 0.06, 0.07, 0.08, 0.10, and 0.15). No phase transition is detected and all ceramics exhibited the perovskite structure consisting of the rhombohedral (R3c) and tetragonal (P4bm) phases. By increasing the Ca(Mg1/3Nb2/3)O3(CMN) content, the average grain size shows a slight change. More specifically, the grain size is 1.00 µm when x < 0.10 and then increases to 1.20 µm in x = 0.10 and 0.15. When x = 0.07, an optimum energy storage performance with recoverable energy density (Wrec) of 4.13 J cm−3 is achieved under an electric field of 340 kV cm−1. At the same time, it exhibits excellent pulse performance at 25 °C, with an effective discharging time (t0.9) of 3.2 ns and a discharge energy density (WD) of 0.61 J cm−3, suggesting a fast charging–discharging rate. In addition, the current density (CD) and power density (PD) are 92.31 A cm−2 and 6.46 MW cm−3, respectively. Overall, the 0.93[0.94(Bi0.5Na0.5)TiO3‐0.06BaTiO3]‐0.07Ca(Mg1/3Nb2/3)O3 ceramics is considered a competitive candidate for the development of high‐energy storage capacitors and pulse‐power devices.