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Perovskite solid solution ceramics of (1 − x)BaTiO3–xBi(Mg2/3Nb1/3)O3 (BT–BMN) (x = 0.05–0.2) were synthesized by solid‐state reaction technique. The results show that the BMN addition could lower the sintering temperature of BT‐based ceramics. X‐ray diffraction results reveal a pure perovskite structure for all studied samples. Dielectric measurements exhibit a relaxor‐like characteristic for the BT–BMN ceramics, where broadened phase transition peaks change to a temperature‐stable permittivity plateau (from −50°C to 300°C) with increasing the BMN content (x = 0.2), and slim polarization–electric field hysteresis loops were observed in samples with x ≥ 0.1. The dielectric breakdown strength and electrical resistivity of BT–BMN ceramics show their maxima of 287.7 kV/cm and 1.53 × 1013 Ω cm at x = 0.15, and an energy density of about 1.13 J/cm3 is achieved in the sample of x = 0.1.

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The electrostrictive effect has some advantages over the piezoelectric effect, including temperature stability and hysteresis-free character. In the present work, we report the diffuse phase transitions and electrostrictive properties in lead-free Fe-doped 0.5Ba(ZrTi)O-0.5(BaCa)TiO (BZT-0.5BCT) ferroelectric ceramics. The doping concentration was set from 0.25 to 2 mol %. It is found that by introducing Fe ion into BZT-0.5BCT, the temperature corresponding to permittivity maximum T was shifted toward lower temperature monotonically by 37 °C per mol % Fe ion. Simultaneously, the phase transitions gradually changed from classical ferroelectric-to-paraelectric phase transitions into diffuse phase transitions with a weak relaxor characteristic. Purely electrostrictive responses with giant electrostrictive coefficient Q between 0.04 and 0.05 m/C are observed from 25 to 100 °C for the compositions doped with 1-2 mol % Fe ion. The Q of Fe-doped BZT-0.5BCT ceramics is almost twice the Q of other ferroelectric ceramics. These observations suggest that the present system can be considered as a potential lead-free material for the applications in electrostrictive area and that BT-based ferroelectric ceramics would have giant electrostrictive coefficient over other ferroelectric systems.

Simultaneous achievement of a large Wrec of 3.51 J cm−3 and a high η of 80.1% in 0.86NN–0.14BNH ceramics under 350 kV cm−1, leading to an excellent comprehensive energy storage performance in lead-free bulk ceramics.

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Ag(Nb0.8Ta0.2)O3 is used here as a model system to shed light on the nature of the low temperature phase behavior of the unsubstituted parent compound AgNbO3, which is an important material for high-power energy storage applications.

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