Yan Dong^#, Huanhuan Dong^#, Juan Wang, Zhiyuan Li, Xinyao Meng, Dongxu Xue, Yu Fang, Junxia Peng*, https://doi.org/10.1039/d6ta02925f

The cooling performance of gel-like cooling materials often declines or fails during prolonged operation because excessive water desorption can cause network collapse and interfacial delamination. Here we present a design strategy that balances strong water retention with controlled water desorption to extend the service lifetime of gel-like cooling materials. An atmospheric hygroscopic eutectogel (EG-SBMA) was prepared by integrating a hygroscopic deep eutectic solvent with a zwitterionic network. The EG-SBMA exhibits good compressibility and adhesiveness, allowing it to adhere to various substrates without detachment even after moisture saturation (90% RH, 12 h). It exhibits good water affinity with a water uptake of 1.2 g g^-1 at 90% RH and 25°C (12 h). When applied to commercial solar cell, EG-SBMA achieves a maximum temperature reduction of 15°C under 1 kW m^-2 illumination and sustains effective cooling for 12 h. Notably, EG-SBMA can be regenerated by overnight atmospheric moisture sorption and subsequently provides ~15°C cooling for another 12 h. The regeneration-cooling cycle is repeatable for ten consecutive cycles, retaining an 11°C temperature drop in the tenth cycle, owing to rapid sorption/desorption equilibration and robust water retention. These results highlight the potential of hygroscopic eutectogels for long-term practical thermal management.

Figure 1. Hygroscopic performance of the EG-SBMA eutectogel

Figure 2 Application of EG-SBMA eutectogel in passive cooling of solar cells

Figure 3. Long-term and cyclic cooling and outdoor cooling performance of EG-SBMA eutectogel

First Authors: Dong Yan, master’s student, Dong Huanhuan, doctoral candidate, Shaanxi Normal University

Correspondence Author: Prof. Peng Junxia, Shaanxi Normal University

Full Text Link: https://doi.org/10.1039/d6ta02925f