Shape-Stabilized Imidazole-Based Ionic Liquid Sorbents for High-Performance Thermal Management

Passive cooling technology based on the water sorption/desorption principle is a promising strategy to realize high-performance thermal management of electronic devices. Nevertheless, the practical application of this technique is severely restricted by some inherent shortcomings of sorbents, including limited water capacity, low heat storage density, and poor shape stability. Herein, a facile method is proposed to develop a novel water sorbent, in which an ionic liquid (1-ethyl-3-methylimidazole acetate, EA) is dispersed in the pores of fumed silica (SiO 2 ) by physical mixing and vacuum impregnation. The results exhibited that the fumed SiO 2 matrix successfully loaded EA, providing outstanding shape stability for the composite sorbent. Remarkably, the 55%EA@SiO 2 composite not only has an enhanced water sorption capacity up to twice that of conventional silica gel (0.6 g/g at 25 °C and 80% relative humidity), but also has a high desorption enthalpy of 1524 J/g. In addition, the 55%EA@SiO 2 can desorb moisture to absorb exterior thermal energy, reducing the surface temperature of the 3W electronic device from 75°C by 23%. Therefore, the proposed shape-stabilized ionic liquid composites show great potential for high-performance thermal management of electronic devices.