Relaxor ferroelectrics are promising candidates for pulsed power dielectric capacitor applications because of their excellent energy-storage properties. Different from most relaxor ferroelectrics whose energy-storage density was improved by increasing the breakdown strength and reducing the remanent polarization, in this study, anti-ferroelectric (AFE) AgNbO₃ (AN) was used to partially substitute the relaxor ferroelectric 0.76Bi_0.5Na_0.5TiO₃–0.24SrTiO₃ (BNT–ST) of morphotropic phase boundary (MPB) composition to reduce the remanent polarization while maintaining large maximum polarization. In this way, a large recoverable energy-storage density (2.03 J cm⁻³) was obtained in the BNT–ST–5AN ceramics under lower electric field of 120 kV cm⁻¹, which is superior to other lead-free energy-storage materials under similar electric fields. Moreover, excellent temperature (25–175 °C) and frequency (1–100 Hz) stabilities are achieved. This performance demonstrates that the BNT–ST–5AN ceramics form a promising class of dielectric capacitive material for high-temperature pulsed power capacitors with large energy-storage density.

Significantly enhanced energy density is obtained at a low electric field by embedding aligned BaTiO₃ nanowires in a polymer matrix via a new physical-assisted casting method.