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Electrocaloric refrigeration which is environmentally benign has attracted considerable attention. In distinction to ferroelectric materials, which exhibit an extremely high positive electrocaloric effect near the Curie temperature, antiferroelectric materials represented by PbZrO3 have a specific negative electrocaloric effect, i.e., electric field decreases the temperature of the materials. However, the explanation of the microscopic mechanism of the negative electrocaloric effect is still unclear, and further research is still needed to provide a theoretical basis for the negative electrocaloric effect enhancement. Herein, the antiferroelectric phase-field model has been proposed to design polar boundaries enhancing antiferroelectric negative electrocaloric performance in PbZrO3-based materials. Based on this, we have simulated the polarization response and domain switching process of the temperature and electric field-induced antiferroelectric—ferroelectric phase transition. It is shown that the temperature range tends to increase as the density of polar boundaries increases from the antiferroelectric stripe domain, polymorphic domain to the nanodomain. Among them, the peak adiabatic temperature change of antiferroelectric nanodomains can reach −13.05 K at 84 kV/cm, and a wide temperature range of about 75 K can be realized at 42 kV/cm. We expect these discoveries to spur further interest in the potential applications of antiferroelectric materials for next-generation refrigeration devices. [ABSTRACT FROM AUTHOR]

Due to miniaturization and environmental friendliness, the electrocaloric effect is expected to be applied to refrigerate electronic chips and microdevices. Unlike the conventional electrocaloric effect that focuses on the temperature change, the ultrafast cooling rate is crucial to heat transport in future device units. In this work, controlling the duration of ultrafast electric field pulse on a nanosecond scale (the frequency ∼ GHz), the instant electrocaloric effect is realized in BaTiO3 and Ba(1−x)SrxTiO3 systems based on the modified phase‐field method. A significant ultrafast cooling rate of 108K s−1 can be achieved due to the application of ultrafast electric field pulse within nanoseconds, which proved to be more efficient than the constant electric field. Furthermore, multiple electric field pulses are designed to realize the cyclic ultrafast cooling. This study provides the fundamental theoretical guidance for ultrafast cooling in solid‐state refrigeration. [ABSTRACT FROM AUTHOR]