Enhancement of electrocaloric strength by grain configuration design

Electrocaloric refrigeration technology presents a promising approach for cooling systems by cyclic processes of applying and removing an electric field to ferroelectric materials. However, dielectric breakdown remains a significant challenge in achieving a substantial temperature change. Chemical modification strategies aimed at enhancing breakdown strength by reducing grain size, but it also suppresses ferroelectric polarization, detrimental to electrocaloric performance. In this study, we addressed this issue by successfully achieving high breakdown strength and significant polarization in 0.3Pb(Mg 1/2 W 1/2 )O 3 -0.3Pb(Ni 1/3 Nb 2/3 )O 3 -0.4PbTiO 3 (PMW-PNN-PT) material by filling large grain gaps with small grains through glass powder doping. Specifically, at an optimized proportion of 0.7 wt% of the glass powder, the maximum electric field in the electrocaloric effect measurements via the direct method increased from 20 kV/cm to 50 kV/cm, and the corresponding electrocaloric temperature change rose from 0.21 K to 0.6 K. This approach represents a novel method to simultaneously enhance breakdown strength and polarization, resulting in a remarkable improvement in the electrocaloric performance.