Ultrahigh Energy Storage Density and Efficiency Achieved in PbZrO₃-Based Antiferroelectric Ceramics via Phase Modulation Engineering

Energy storage systems are crucial in modern technology, especially for electric vehicles and photovoltaic systems that demand superior power density and rapid charge-discharge rates. While lead zirconate-based (PZ) ceramics have high charge-discharge power density and potential for high-performance parameter modulation, their low energy storage density, together with low efficiency, limits practical applications. To address the crucial problem, this study has investigated the effect of Ca²⁺ doping in the (Pb_{0.97-<i>x</i>}Ca_<i>x</i>La_0.02)[Nb_0.02(Zr_0.6Sn_0.4)_0.975]O₃ antiferroelectric matrix to enhance their energy storage performance. The competition-modulation relationship between the orthorhombic and tetragonal phases was successfully introduced in this way, and the structural modification accounts for improved multistage phase transition behavior under external applied electric fields and the optimization of multiple performance parameters. The breakdown strength (BDS) was enhanced through grain size refinement and the effective suppression of oxygen vacancy formation, which were related to phase modulation induced by Ca²⁺ incorporation. Furthermore, the diffuse phase transition behavior was optimized due to the improved response mechanism of the room-temperature O-T mixed phase under applied field. This improvement was associated with the modulation of the cation vibration environment. CN4 (x = 0.04) ceramics exhibited a recoverable energy density of 11.40 J/cm³ and an outstanding energy efficiency of 94.67% under a high electric field of 563 kV/cm. This work provided a rather effective potential of phase modulation strategies for developing the performance of antiferroelectric ceramics in high-power energy storage applications.