Interdigitated structure-derived scalable all-solid-state electrocaloric cooling device using lead-free BaSrTiO3-based multilayer ceramics

Solid-state electrocaloric (EC) refrigeration is regarded as a promising alternative to traditional vapor-compression refrigeration. However, good cooling materials are still one of the challenges for prototypes. In this work, a dual-strategy scalable interdigital structure for solid-state EC refrigeration devices based on base metallic electrode and lead-free BaSrTiO₃-based multilayer ceramics (MLCs) was designed and fabricated. Thermal pads are used as thermal interface materials in the device. A maximum temperature span ($T_{\text{span}}$$T_{\text{span}}$) of 0.66 K and a cooling power of 52 mW at 0 K $T_{span}$$T_{span}$ was obtained in a single-stage device with a cooling power density of 49.9 W/kg and 282 W/L, which is larger than that of prototypes based on BaTiO₃ (19 W/kg and 110 W/L) and PbScTaO₃ (18 W/kg and 140 W/L) MLCs. Furthermore, a maximum $T_{\text{span}}$$T_{\text{span}}$ of 7.13 K and a cooling power of 119 mW at 0 K $T_{\text{span}}$$T_{\text{span}}$ can also be realized using the scaling-up strategy.