Reconstructing phase transition pathways in PbZrO3-based ceramics through composition-controlled metastable state engineering

Orthorhombic PbZrO 3 -based antiferroelectrics are promising candidates for high-energy-density capacitors, yet the mechanism governing the composition- and temperature -dependent multiphase transitions remain unclear. Here, we investigate Pb 0.97 La 0.02 Zr 1– x Sn x O 3 (PLZS- x , x = 0–0.55) ceramics to clarify the evolution of phase transitions and antiferroelectric behavior with composition, temperature, and electric field. All compositions exhibit an orthorhombic Pbam symmetry, while Sn incorporation markedly alters the polarization response. As the Sn content increases, the typical double hysteresis loops gradually transform into multiple hysteresis loops, along with reduced polarization hysteresis and improved energy storage efficiency. According to dielectric and ferroelectric measurements, the phase diagram of PLZS- x ceramics was reconstructed, revealing several intermediate states related to multiphase transition. This evolution is rationalized using the Kittel model, in which the negative coupling term − P 2 Q 2 stabilizes intermediate metastable states in the free-energy landscape. These states enable sequential transitions under electric fields, leading to multiphase transition behavior. An optimal energy storage performance is achieved in the x = 0.20 composition, with a recoverable energy storage density of 10.02 J/cm 3 and an efficiency of 86.45% under 35 kV/mm. These findings clarify the phase transition behavior of PLZS- x antiferroelectric ceramics and provide valuable guidance for designing high-performance PbZrO 3 -based energy storage materials.