Enhanced electrocaloric effect in ferroelectric ceramics via defect dipole engineering

The increasing demand for higher operating speeds and greater integration densities in electronic devices has made heat dissipation one of the most critical challenges for next-generation technologies. This challenge has driven extensive efforts aimed at achieving a giant electrocaloric effect in ferroelectrics for high-efficiency cooling. Here, we propose a defect dipole engineering strategy to manipulate the polarization behavior of ferroelectric ceramics, leading to superior electrocaloric effect. By incorporating Sm and Li ions, the (Sm_Bȧ-Li_Ba') defect dipoles enhance the polarizability of BaTiO₃. Simultaneously, these dipole defects increase the carrier activation energy, effectively mitigating the inherent trade-off between high breakdown strength and high polarization, thereby allowing the application of a high electric field to fully activate the electrocaloric potential. As a result, defect dipole engineering enables BaTiO₃ to achieve a remarkable electrocaloric effect over a wide temperature range, achieving a high temperature change of 2.7 K at 70 °C- typical for integrated circuits.