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.