High energy storage efficiency and fast discharge property of temperature stabilized Ba0.4Sr0.6TiO3–Bi(Mg0.5Ti0.5)O3 ceramics

(1?x)Ba_0.4Sr_0.6TiO₃-xBi(Mg_0.5Ti_0.5)O₃ ((1?x)BST-xBMT) relaxor ferroelectric ceramics were prepared by a conventional solid-state method. In this work, the microstructure, dielectric properties, and pulsed charge–discharge properties were investigated. The doping of BMT caused a decrease in the surface energy and grain boundary energy, and contributed to the formation of polar nanoregions (PNRs). The existence of PNRs was confirmed by piezoresponse force microscopy measurements (PFM) on the 0.8BST-0.2BMT ceramic. The PNRs responded quickly under an AC voltage, thus the pulsed charge–discharge time was short (<80 ns), aiming to realize time compression to improve the power density (P_D). The PNRs were not closely connected to each other and adverse to the formation of leakage current and pinning, thus inhibiting charge transfer at the grain boundaries and contributing to the high energy storage efficiency (η ～ 93%). In addition, the 0.8BST-0.2BMT ceramic also displayed excellent temperature stability. The capacitance-temperature dependence satisfied the requirement of X8R (?55–150 °C, ΔC/C_{25 °C} ≤ ±15%), and η had no obvious fluctuation in the temperature range from 25 °C to 150 °C. This study could provide a successful method to achieve a temperature stable and high η, and a fast charge–discharge process.