Ultrahigh energy density and efficiency of BaTiO3-based ceramics via multiple design strategies

•Multiple design strategies could improve relaxation and insulation performance.•Excellent Wrec ∼7.12 J/cm3 and η ∼90% are realized.•Superb temperature, frequency stability and anti-fatigue characteristics are achieved. The market-dominating of electrostatic capacitors of BaTiO3 are essential in advanced power supply system due to their quickly store and release electrical energy. However, the relatively low energy storage capability impedes miniaturization and integration in present-day electronics. In this study, we investigate the addition of (Sr0.7Bi0.2)(Mg1/3Ta2/3)O3 (SBMT) as a dopant into 0.75BaTiO3-0.25Na0.5Bi0.5TiO3 (BT-NBT) to form a solid solution. SBMT effectively improve the relaxation behavior and insulation performance of the ceramic, increases the breakdown strength (Eb) and reducing hysteresis loss, this leads to a synergistic improvement in the energy storage density (Wrec) and efficiency (η). The best performing composition was found to be 0.80(BT-NBT)-0.20SBMT, which produced a combination of Eb ∼720 kV/cm, Wrec ∼7.12 J/cm3, and η ∼90%, These values are superior to those of BaTiO3 and other BaTiO3-based ferroelectric ceramics. Additionally, this composition exhibits almost fatigue-free Wrec after 104 switching cycles, even at elevated temperatures of up to 200 °C. These exceptional capabilities demonstrate significant potential for practical device applications.