Giant electrocaloric strength and adiabatic temperature change of BiFeO ₃ /P(VDF‐TrFE) flexible composite films

Abstract This paper reports that flexible composite films containing BiFeO 3 nanoparticles demonstrate substantial electrocaloric strength and adiabatic temperature change of 407 mK m MV −1 and 24.4 K for a 10 wt% solid content, respectively. These values significantly surpass previously reported data. We discovered that crystallite sizes exceeding 10 nm in the polar β ‐phase are essential for amplifying the electrocaloric effect, allowing for easier domain motion at lower electric fields. Simulations based on Landau theory validate the electrocaloric effect in the BiFeO 3 /P(VDF‐TrFE) composite film, predicting it can induce a 34 K adiabatic temperature change under 120 MV m −1 . This finding offers a basis for selecting between high cooling performance and energy efficiency for practical applications. The research showcases a flexible composite film with potential practical applications in solid‐state refrigeration technologies.