Achieving improved electrocaloric effect and broad operation temperature by tailoring phase fraction in BaTiO3-based ceramics

Ferroelectric electrocaloric (EC) materials are a pivotal part of sustainable micro-cooling, which complements conventional cooling methods in miniaturized devices. However, the application of EC materials is largely limited by the unsatisfactory room-temperature EC response and narrow operation temperature window. In this work, with careful tuning the composition of BaTiO 3 (BT)-based ceramics through the conventional doping method, enhanced EC properties were achieved in Ba 0.8 Sr 0.2 Zr x (Ti 0.999 Mn 0.001 ) 1- x O 3 (BSZMT) ( x  = 0.05, 0.10, 0.15, and 0.20). We especially found that the electrocaloric temperature change ( ΔT ) of > 0.50 K was achieved in a broaden temperature ranging from 20 °C to 95 °C and a peak ΔT value of 1.08 K was achieved at temperature of 70 °C in our BSZMT with x  = 0.15. To ascertain the physical mechanism, we employed hybrid characterization methods including XRD , Raman, and dielectric analysis together with Density Functional Theory (DFT) calculation. Our results clearly show that the doped Zr and Mn at B site of BSZMT effectively modulate the microstructure leading to coexistence of different ferroelectric phases and broken long-range ferroelectric order, which subsequently results in the enhanced EC performance and broad operating temperature window.