Enhanced electrocaloric effect in lead-free organic and inorganic relaxor ferroelectric composites near room temperature

Abstract

We study the electrocaloric effect in the composites composed of the ferroelectric poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) [P(VDF-TrFE-CFE)] terpolymer matrix and lead-free BaZr0.2Ti0.8O3 (BZT) fillers. The P(VDF-TrFE-CFE)/BZT composite with 5 vol. % BZT exhibits a high adiabatic temperature change of ΔT = 7.4 K and a large isothermal entropy change of ΔS = 30 J kg−1 K−1 under an electric field of 90 MV m−1 at room temperature. The electrocaloric response in the composites is significantly enhanced when compared to those of the constituent components, which has been attributed to the polymer-filler interfacial coupling effect. In addition, the composites display a wide operational temperature window as a result of their ferroelectric relaxor nature.