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 titanate-based (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-BTZ-xBST ceramics by carefully balancing the relationships among density, dielectric breakdown strength (BDS), and ΔT. Although ΔT intuitively decreases with increasing density, enhanced BDS can partially compensate for this decrease. An excellent EC performance with ΔT of 2.21 K and ΔT/ΔE of 0.471 K mm kV−1 is obtained in x = 0.5, together with a broader temperature span of 50.3 °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.