Boosting room-temperature electrocaloric performance in B-site complex antiferroelectrics: A synergistic design approach

As an emerging eco-friendly solid-state refrigeration technology boasting high energy conversion efficiency, there is a pressing demand for ferroelectrics exhibiting significant electrocaloric effect (ECE) at room temperature (RT) for refrigeration applications. In this study, guided by phase-field simulation, we explore the potential of B-site complex Pb[Mg_(1–x)Zn_xW]_1/2O₃ (PMZW100x) antiferroelectrics (AFE) to deliver promising symmetric positive and negative ECE near ambient temperature. The first-order AFE-paraelectric (PE) phase transition occurring around 50 °C induces a substantial change in heat quantity and yields prominent ECE upon electric excitation. Maxwell characterization reveals a potential combination of positive and negative ECE, showcasing significant advantages in cooling capacity. Given the technical limitations of existing direct methods for testing under elevated electric fields, low-field ECE is validated using the heat flux approach to ensure the legitimacy of results. Direct measurements demonstrate a high positive ΔT value of 2.76 K at 52 °C and a negative ΔT of –2.91 K at 44 °C (under 140 kV cm^–1), surpassing traditional PbZrO₃ bulk materials. The coexistence of substantial positive and negative ΔT near RT in PMZW100x offers a new avenue for developing highly efficient solid-state cooling devices.