Large electrocaloric effect in ferroelectric materials

The electrocaloric effect (ECE) in polar materials shows great potential in realizing high efficient solid-state cooling devices with a smaller size and high efficiency. The thermodynamic theory was introduced in order to achieve a large ECE in ferroelectrics. The previous experimental researches were reviewed and discussed. A novel method to directly measure the ECE entropy change and temperature change was developed. Results indicated that the relaxor ferroelectric polymers and first-order phase transition polymers demonstrated larger ECE. Recently published larger electrocaloric effect in BaTiO₃ crystal and multilayer ceramic capacitors, and the prototype ferroelectric cooling devices reveal attractive application prospects in the near future.