Highly Efficient Cooling via Synergistic Electro-Thermal Phase Changes.

Abstract

Electro-phase change materials (electro-PCM), based on the electrocaloric effect, have attracted significant attention and achieved rapid development in the field of cooling technology owing to their environmental protection, low energy consumption, and miniaturization. However, due to their limited isothermal entropy change and thermal conductivity, the cooling capacity of the electro-PCM devices has severely limited their cooling effect on electronic devices. Here, with the synergistic electro-thermal phase changes, the entropy change and thermal conductivity of electro-PCM are significantly improved by stacking it with thermo-phase change materials (thermo-PCM). Compared with that of the electro-PCM, the entropy change and thermal conductivity of electro-thermal phase change materials (ETPCM) stack can be up to 4.68-fold (from 28.31 to 132.35 J kg^-1 K^-1 at electric field of 100 MV m^-1) and 2.39-fold (from 0.18 to 0.43 W m^-1·K^-1), respectively. The practicality of this strategy has also been fully validated by cooling a simulated electronic chip (1.75 W cm^-2) with a temperature drop of 49.32 K after constructing ETPCM stack-based cooling device using the electrostatic actuation prototype. The synergistic enhancement of entropy change and thermal conductivity paves the way for the future direction of electrocaloric cooling toward interdisciplinary fusion.