Superior Energy and Power Density Realized in Pb(Hf_1-xTi_x)O₃ System at Low Electric Field

The development of antiferroelectric materials with large energy density and fast discharge speed makes dielectric capacitors possess great prospects for applications in pulsed power technology. Here, the PbHfO₃-based ceramics with compositions of Pb(Hf_1-xTi_x)O₃ (PHT, 0.01 ≤ x ≤ 0.05) were synthesized, and their antiferroelectricity and phase transition behavior were studied. According to the tests of x-ray diffraction, dielectric spectrum, and polarization–electric field hysteresis loops, PHT ceramics gradually transition from an orthorhombic symmetric antiferroelectric phase to a hexagonal symmetric ferroelectric phase at room temperature as Ti⁴⁺ concentration increases. The forward phase switching field of antiferroelectric to ferroelectric phase transition can be markedly regulated by the introduction of Ti⁴⁺, and the optimal energy storage performance was obtained in Pb(Hf_0.98Ti_0.02)O₃ ceramics with a large recoverable energy storage density of W_rec ~ 4.15 J/cm³ and efficiency of η ~ 65.3% only at a low electric field of 190 kV/cm. Furthermore, the outstanding charge–discharge properties with an ultrafast discharge time (71 ns), remarkable discharged energy density (2.84 J/cm³), impressive current density (1,190 A/cm²), and ultrahigh power density (101 MW/cm³) at a low electric field of 170 kV/cm were obtained in studied ceramics. The excellent energy storage performance of PHT ceramics provides a promising platform for the application of dielectric capacitors.