Development of electrocaloric effect in BT-based lead-free ceramic via density adjustment strategy

Electrocaloric (EC) refrigeration materials have seen significant progress recently, with efficient Barium titanatebased (BT-based) lead-free materials particularly promising for microelectronics applications. However, their performance still lags behind their lead-based counterparts, highlighting the need for further improvements. This study employs a novel density adjustment strategy (DAS) to enhance the EC performance of (0.5-x)BCT-BTZxBST ceramics by carefully balancing the relationships among density, dielectric breakdown strength (BDS), and Delta T. Although Delta T intuitively decreases with increasing density, enhanced BDS can partially compensate for this decrease. An excellent EC performance with Delta T of 2.21 K and Delta T/Delta E of 0.471 K mm kV-1 is obtained in x = 0.5, together with a broader temperature span of 50.3 degrees C near room temperature, which surpasses or is comparable to other lead-free or lead-based ones. The results suggest that the DAS provides a promising approach for developing efficient EC, making speediness of application in EC devices.