Design, synthesis and Characterization of a novel antiferroelectric solid solution (1-x)PbHfO₃-xBiAlO₃

Antiferroelectric (AFE) materials are potentially useful for energy storage applications. Lead hafnate (PbHfO₃) is one of the prototypical AFE materials. However, its critical field (E_cr) which is needed to induce the AFE to ferroelectric phase transition is close to the dielectric breakdown strength. To reduce E_cr, we prepare the solid solutions of (1-x)PbHfO₃–xBiAlO₃ (x = 0.00–0.04) via solid state synthesis. The crystal structures, dielectric behaviour, ferroelectric properties, and energy storage properties are investigated. A temperature-composition phase diagram is established. At room temperature, the crystal symmetry of all compositions is orthorhombic with the Pbam space group. Upon heating, the transition to the AFE orthorhombic Imma phase is observed at the temperature T_C1, which slightly decreases with increasing x, followed by the transition to the cubic phase at the temperature T_C2, which does not depend on x. Distinct dielectric anomalies are observed at T_C1 and T_C2. It is found that BiAlO₃ substitution reduces E_cr and the polarization–electric field relations display characteristic double hysteresis loops. For x = 0.04, at a comparatively small applied field of 130 kV/cm, the values of recoverable energy density (W_rec) and efficiency of 0.24 J/cm³ and 84 %, respectively, are obtained. At 190 °C, a W_rec = 0.75 J/cm³ and a very high efficiency of 92 % are obtained at the field of 50 kV/cm. Thus, the prepared material can potentially be used in high-temperature pulsed power capacitors for energy storage applications within the temperature range from room temperature up to 190 °C.