Enhanced Energy Storage Performance by A-B Site Ambipolar Co-Doping in Antiferroelectrics

Antiferroelectric materials are promising to be used for power capacitive devices. To improve the energy storage performance, solid-solution and defect engineering are widely used to suppress the long-range order by introducing local heterogeneities. However, both methods generally deteriorate either the maximum polarization or breakdown electric field due to damaged intrinsic polarization or increased leakage. Here, we show that forming defect-dipole clusters by A-B site acceptor-donor co-doping in antiferroelectrics can comprehensively enhance the energy storage performance. We took the La-Mn co-doped (Pb_0.9Ba_0.04La_0.04)(Zr_0.65Sn_0.3Ti_0.05)O₃ (PBLZST) as an example. For co-doping with unequal amounts, high dielectric loss, impurity phase, and decreased polarization were observed. By contrast, La and Mn in an equal amount of co-doping can significantly improve the overall energy storage performance. An over 48% increasement in both the maximum polarization (62.7 μC/cm²) and breakdown electric field (242.6 kV/cm) was obtained in 1 mol % La and 1 mol % Mn equally co-doped PBLZST, followed by a nearly two-time enhancement in W_rec (6.52 J/cm³) compared with that of the pure matrix. Moreover, a high energy storage efficiency of 86.3% with an enhanced temperature stability over a wide temperature range can be achieved. The defect-dipole clusters associated with charge-compensated co-doping are suggested to contribute to an enhanced dielectric permittivity, linear polarization behavior, and maximum polarization strength compared with that of the unequal co-doping cases. The defect-dipole clusters are suggested to couple with the host, leading to a high energy storage performance. The proposed strategy is believed to be applicable to modify the energy storage behavior of antiferroelectrics.