Influence of protective layer thinning on the electrocaloric performance of 0.8Ba(Ti0.82Zr0.18)O3–0.2Ba(Ti0.9Sn0.1)O3 multilayer ceramic films

The multilayer electrocaloric ceramics (MLEC) are promising candidates for environmentally friendly refrigeration, since it possesses large electrocaloric effect (ECE) at a relatively low applied voltage. In this work, factors that may influence the ECE of MLEC are investigated. Experimental results demonstrate that the ECE of MLEC is strongly related to its effective volume fraction, and the effective volume fraction of the MLEC can be tailored by changing the thickness of the MLEC protective layer. Measurements show up to a 33.3% improvement of adiabatic temperature change when the thickness of MLEC protective layers is decreased by 70.0%. Meanwhile, the relaxation and the temperature range of the MLEC is increased with the increase of frequency. The enhanced ECE response is obtained over a broad temperature range from 0 °C to 50 °C in MLEC. It is found that the ECE response of MLEC could be enhanced by thinning the protective layer, and this enhancement is induced by the increasing of the effective volume fraction which is caused by the protective layer thinning. As a result, this work provides an effective and feasible way to develop high-performance MLEC components.