Design of BaTiO 3 lead-free ceramics enabling ultrahigh electrocaloric effect and wide working temperature range

The development of high-performance electrocaloric effect (ECE) is of great importance for local refrigeration (such as chip and wearable electronics cooling, etc.). However, how to simultaneously achieving both a large ECE and a wide working temperature range near the room temperature are long-term challenges for lead-free ceramics. Herein, we report a novel lead-free ceramic with a high-performance ECE. Phase coexistence and optimized ferroelectric domain configuration and ultra-fine grains were constructed by {Nb 5+ , In 3+ } co-doping in B 0.9 Ca 0.1 TiO 3 ceramics near the room temperature. Ultimately, an ultrahigh ECE of 3.0 K and a wide working temperature range of 97 K are obtained near the room temperature in the composition (B 0.9 Ca 0.1 Ti 0.89 (Nb 0.5 In 0.5 ) 0.11 O 3 ). Furthermore, the origin of the high ECE performance was elucidated by the microstructures characterized using piezoresponse force microscopy (PFM) and atomic-resolution HAADF-STEM, and the dielectric and ferroelectric properties. This work provides an innovative approach for achieving high-performance ECE.