Issue

Vol. 18 (2026)

Radiative Coupled Evaporation Cooling Hydrogel for Above-Ambient Heat Dissipation and Flame Retardancy

https://doi.org/10.1007/s40820-025-01903-0
Qin Ye
School of Energy Science and Engineering, Central South University, Changsha 430001, People’s Republic of China
Yimou Huang
School of Energy Science and Engineering, Central South University, Changsha 430001, People’s Republic of China
Baojian Yao
School of Energy Science and Engineering, Central South University, Changsha 430001, People’s Republic of China
Zhuo Chen
School of Energy Science and Engineering, Central South University, Changsha 430001, People’s Republic of China
Changming Shi
School of Engineering, Brown University, Providence, RI 02912, USA
Brian W. Sheldon
School of Engineering, Brown University, Providence, RI 02912, USA
Meijie Chen
School of Energy Science and Engineering, Central South University, Changsha 430001, People’s Republic of China

Corresponding Author: Meijie Chen

chenmeijie@csu.edu.cn

Nano-Micro Letters, Vol. 18 (2026), Article Number: 50

Abstract

By combining the merits of radiative cooling (RC) and evaporation cooling (EC), radiative coupled evaporative cooling (REC) has attracted considerable attention for sub-ambient cooling purposes. However, for outdoor devices, the interior heating power would increase the working temperature and fire risk, which would suppress their above-ambient heat dissipation capabilities and passive water cycle properties. In this work, we introduced a REC design based on an all-in-one photonic hydrogel for above-ambient heat dissipation and flame retardancy. Unlike conventional design RC film for heat dissipation with limited cooling power and fire risk, REC hydrogel can greatly improve the heat dissipation performance in the daytime with a high workload, indicating a 12.0 °C lower temperature than the RC film under the same conditions in the outdoor experiment. In the nighttime with a low workload, RC-assisted adsorption can improve atmospheric water harvesting to ensure EC in the daytime. In addition, our REC hydrogel significantly enhanced flame retardancy by absorbing heat without a corresponding temperature rise, thus mitigating fire risks. Thus, our design shows a promising solution for the thermal management of outdoor devices, delivering outstanding performance in both heat dissipation and flame retardancy.


Highlights:
1 An all-in-one photonic hydrogel was designed for above-ambient heat dissipation and flame retardancy by sky radiative cooling and evaporation cooling.
2 Radiative coupled with evaporation cooling can greatly improve the heat dissipation performance, indicating a 12.0 °C lower than the radiative cooling film under the same conditions.
3 Radiative cooling-assisted adsorption can improve atmospheric water harvesting to ensure evaporation under periodic workload and meteorological parameters.

Keywords

Radiative cooling Evaporation cooling Heat dissipation Photonic hydrogel Flame retardancy
Ye, Qin, Yimou Huang, Baojian Yao, Zhuo Chen, Changming Shi, Brian W. Sheldon, and Meijie Chen. 2025. “Radiative Coupled Evaporation Cooling Hydrogel for Above-Ambient Heat Dissipation and Flame Retardancy”. Nano-Micro Letters 18 (September):50. https://doi.org/10.1007/s40820-025-01903-0.
Download Citation
Endnote/Zotero/Mendeley (RIS)
BibTeX
References
  1. F. Yi, Y. Gan, R. Liu, F. Liu, Y. Li, Experimental investigation on the heat transfer performance of a microchannel thermosiphon array for 5G telecommunication base stations. Appl. Therm. Eng. 242, 122561 (2024). https://doi.org/10.1016/j.applthermaleng.2024.122561
  2. C. Park, W. Lee, C. Park, S. Park, J. Lee et al., Efficient thermal management and all-season energy harvesting using adaptive radiative cooling and a thermoelectric power generator. J. Energy Chem. 84, 496–501 (2023). https://doi.org/10.1016/j.jechem.2023.05.051
  3. A. Zuazua-Ros, C. Martín Gómez, J.C. Ramos, J. Bermejo-Busto, Towards cooling systems integration in buildings: experimental analysis of a heat dissipation panel. Renew. Sustain. Energy Rev. 72, 73–82 (2017). https://doi.org/10.1016/j.rser.2017.01.065
  4. C. Pan, Z. Jia, J. Wang, L. Wang, J. Wu, Optimization of liquid cooling heat dissipation control strategy for electric vehicle power batteries based on linear time-varying model predictive control. Energy 283, 129099 (2023). https://doi.org/10.1016/j.energy.2023.129099
  5. S. Xue, G. Huang, Q. Chen, X. Wang, J. Fan et al., Personal thermal management by radiative cooling and heating. Nano-Micro Lett. 16(1), 153 (2024). https://doi.org/10.1007/s40820-024-01360-1
  6. H. Yu, J. Lu, J. Yan, T. Bai, Z. Niu et al., Selective emission fabric for indoor and outdoor passive radiative cooling in personal thermal management. Nano-Micro Lett. 17(1), 192 (2025). https://doi.org/10.1007/s40820-025-01713-4
  7. A.-Q. Xie, H. Qiu, W. Jiang, Y. Wang, S. Niu et al., Recent advances in spectrally selective daytime radiative cooling materials. Nano-Micro Lett. 17(1), 264 (2025). https://doi.org/10.1007/s40820-025-01771-8
  8. Q. Ye, X. Chen, H. Yan, M. Chen, Thermal conductive radiative cooling film for local heat dissipation. Mater. Today Phys. 50, 101626 (2025). https://doi.org/10.1016/j.mtphys.2024.101626
  9. N. Guo, C. Shi, N. Warren, E.A. Sprague-Klein, B.W. Sheldon et al., Challenges and opportunities for passive thermoregulation. Adv. Energy Mater. 14(34), 2401776 (2024). https://doi.org/10.1002/aenm.202401776
  10. Z. Yan, H. Zhai, D. Fan, Q. Li, Biological optics, photonics and bioinspired radiative cooling. Prog. Mater. Sci. 144, 101291 (2024). https://doi.org/10.1016/j.pmatsci.2024.101291
  11. Z. Zhang, M. Yu, C. Ma, L. He, X. He et al., A Janus smart window for temperature-adaptive radiative cooling and adjustable solar transmittance. Nano-Micro Lett. 17(1), 233 (2025). https://doi.org/10.1007/s40820-025-01740-1
  12. Z. Yan, G. Zhu, D. Fan, Q. Li, Bioinspired metafabric with dual-gradient Janus design for personal radiative and evaporative cooling. Adv. Funct. Mater. 35(2), 2412261 (2025). https://doi.org/10.1002/adfm.202412261
  13. W. Xie, C. Xiao, Y. Sun, Y. Fan, B. Zhao et al., Flexible photonic radiative cooling films: fundamentals, fabrication and applications. Adv. Funct. Mater. 33(46), 2305734 (2023). https://doi.org/10.1002/adfm.202305734
  14. X. Wang, X. Liu, Z. Li, H. Zhang, Z. Yang et al., Scalable flexible hybrid membranes with photonic structures for daytime radiative cooling. Adv. Funct. Mater. 30(5), 1907562 (2020). https://doi.org/10.1002/adfm.201907562
  15. J. Liu, Y. Du, S. Zhang, J. Yan, Spectrally engineered textiles for personal cooling. Joule 8(10), 2727–2731 (2024). https://doi.org/10.1016/j.joule.2024.08.012
  16. M. Chen, D. Pang, H. Yan, Colored passive daytime radiative cooling coatings based on dielectric and plasmonic spheres. Appl. Therm. Eng. 216, 119125 (2022). https://doi.org/10.1016/j.applthermaleng.2022.119125
  17. B. Xiang, R. Zhang, Y. Luo, S. Zhang, L. Xu et al., 3D porous polymer film with designed pore architecture and auto-deposited SiO2 for highly efficient passive radiative cooling. Nano Energy 81, 105600 (2021). https://doi.org/10.1016/j.nanoen.2020.105600
  18. S. Liu, F. Zhang, X. Chen, H. Yan, W. Chen et al., Thin paints for durable and scalable radiative cooling. J. Energy Chem. 90, 176–182 (2024). https://doi.org/10.1016/j.jechem.2023.11.016
  19. W. Huang, Y. Chen, Y. Luo, J. Mandal, W. Li et al., Scalable aqueous processing-based passive daytime radiative cooling coatings. Adv. Funct. Mater. 31(19), 2010334 (2021). https://doi.org/10.1002/adfm.202010334
  20. J. Mandal, Y. Fu, A.C. Overvig, M. Jia, K. Sun et al., Hierarchically porous polymer coatings for highly efficient passive daytime radiative cooling. Science 362(6412), 315–319 (2018). https://doi.org/10.1126/science.aat9513
  21. M. Chen, D. Pang, H. Yan, Sustainable and self-cleaning bilayer coatings for high-efficiency daytime radiative cooling. J. Mater. Chem. C 10(21), 8329–8338 (2022). https://doi.org/10.1039/d2tc00834c
  22. M. Chen, D. Pang, X. Chen, H. Yan, Enhancing infrared emission behavior of polymer coatings for radiative cooling applications. J. Phys. D Appl. Phys. 54(29), 295501 (2021). https://doi.org/10.1088/1361-6463/abfb19
  23. J. Huang, D. Fan, Q. Li, Structural rod-like ps for highly efficient radiative cooling. Mater. Today Energy 25, 100955 (2022). https://doi.org/10.1016/j.mtener.2022.100955
  24. M. Chen, D. Pang, J. Mandal, X. Chen, H. Yan et al., Designing mesoporous photonic structures for high-performance passive daytime radiative cooling. Nano Lett. 21(3), 1412–1418 (2021). https://doi.org/10.1021/acs.nanolett.0c04241
  25. M. Chen, D. Pang, X. Chen, H. Yan, Investigating the effective radiative cooling performance of random dielectric microsphere coatings. Int. J. Heat Mass Transf. 173, 121263 (2021). https://doi.org/10.1016/j.ijheatmasstransfer.2021.121263
  26. J. Lee, D. Im, S. Sung, J. Yu, H. Kim et al., Scalable and efficient radiative cooling coatings using uniform-hollow silica spheres. Appl. Therm. Eng. 254, 123810 (2024). https://doi.org/10.1016/j.applthermaleng.2024.123810
  27. C. Park, C. Park, S. Park, J. Lee, Y.S. Kim et al., Hybrid emitters with raspberry-like hollow SiO2 spheres for passive daytime radiative cooling. Chem. Eng. J. 459, 141652 (2023). https://doi.org/10.1016/j.cej.2023.141652
  28. J. Yu, C. Park, B. Kim, S. Sung, H. Kim et al., Enhancing passive radiative cooling films with hollow yttrium-oxide spheres insights from FDTD simulation. Macromol. Rapid Commun. 46(3), 2400770 (2025). https://doi.org/10.1002/marc.202400770
  29. M. Li, Z. Yan, D. Fan, Flexible radiative cooling textiles based on composite nanoporous fibers for personal thermal management. ACS Appl. Mater. Interfaces 15(14), 17848–17857 (2023). https://doi.org/10.1021/acsami.3c00252
  30. C. Cui, J. Lu, S. Zhang, J. Su, J. Han, Hierarchical-porous coating coupled with textile for passive daytime radiative cooling and self-cleaning. Sol. Energy Mater. Sol. Cells 247, 111954 (2022). https://doi.org/10.1016/j.solmat.2022.111954
  31. J. Huang, M. Li, D. Fan, Core-shell ps for devising high-performance full-day radiative cooling paint. Appl. Mater. Today 25, 101209 (2021). https://doi.org/10.1016/j.apmt.2021.101209
  32. X. Song, H. Gong, H. Li, M. Zhang, L. Jiang et al., Molecularly and structurally designed polyimide nanofiber radiative cooling films for spacecraft thermal management. Adv. Funct. Mater. 35(2), 2413191 (2025). https://doi.org/10.1002/adfm.202413191
  33. Y. Zhao, D. Pang, M. Chen, Z. Chen, H. Yan, Scalable aqueous processing-based radiative cooling coatings for heat dissipation applications. Appl. Mater. Today 26, 101298 (2022). https://doi.org/10.1016/j.apmt.2021.101298
  34. M. Chen, D. Pang, X. Chen, H. Yan, Y. Yang, Passive daytime radiative cooling: fundamentals, material designs, and applications. EcoMat 4(1), e12153 (2022). https://doi.org/10.1002/eom2.12153
  35. L. Lei, S. Meng, Y. Si, S. Shi, H. Wu et al., Wettability gradient-induced diode: MXene-engineered membrane for passive-evaporative cooling. Nano-Micro Lett. 16(1), 159 (2024). https://doi.org/10.1007/s40820-024-01359-8
  36. H. Li, J. Ma, W. Yan, J. Lan, W. Hong, Lithium-based water-absorbent hydrogel with a high solar cell cooling flux. Renew. Energy 235, 121277 (2024). https://doi.org/10.1016/j.renene.2024.121277
  37. H. Liu, J. Yu, C. Wang, Z. Zeng, P. Poredoš et al., Passive thermal management of electronic devices using sorption-based evaporative cooling. Device 1(6), 100122 (2023). https://doi.org/10.1016/j.device.2023.100122
  38. X. Liu, P. Li, J. Chen, P. Jiang, Y.-W. Mai et al., Hierarchically porous composite fabrics with ultrahigh metal–organic framework loading for zero-energy-consumption heat dissipation. Sci. Bull. 67(19), 1991–2000 (2022). https://doi.org/10.1016/j.scib.2022.09.014
  39. L. Yu, Y. Huang, W. Li, C. Shi, B.W. Sheldon et al., Radiative-coupled evaporative cooling: fundamentals, development, and applications. Nano Res. Energy 3(2), e9120107 (2024). https://doi.org/10.26599/nre.2023.9120107
  40. X. Dong, K.-Y. Chan, X. Yin, Y. Zhang, X. Zhao et al., Anisotropic hygroscopic hydrogels with synergistic insulation-radiation-evaporation for high-power and self-sustained passive daytime cooling. Nano-Micro Lett. 17(1), 240 (2025). https://doi.org/10.1007/s40820-025-01766-5
  41. Q. Ye, D. Chen, Z. Zhao, H. Yan, M. Chen, Adhesive hydrogel paint for passive heat dissipation via radiative coupled evaporation cooling. Small 21(17), 2412221 (2025). https://doi.org/10.1002/smll.202412221
  42. Y. Sun, Y. Ji, M. Javed, X. Li, Z. Fan et al., Preparation of passive daytime cooling fabric with the synergistic effect of radiative cooling and evaporative cooling. Adv. Mater. Technol. 7(3), 2100803 (2022). https://doi.org/10.1002/admt.202100803
  43. J. Li, X. Wang, D. Liang, N. Xu, B. Zhu et al., A tandem radiative/evaporative cooler for weather-insensitive and high-performance daytime passive cooling. Sci. Adv. 8(32), eabq0411 (2022). https://doi.org/10.1126/sciadv.abq0411
  44. L. Yu, Y. Huang, Y. Zhao, Z. Rao, W. Li et al., Self-sustained and insulated radiative/evaporative cooler for daytime subambient passive cooling. ACS Appl. Mater. Interfaces 16(5), 6513–6522 (2024). https://doi.org/10.1021/acsami.3c19223
  45. C. Lei, Y. Guo, W. Guan, H. Lu, W. Shi et al., Polyzwitterionic hydrogels for efficient atmospheric water harvesting. Angew. Chem. Int. Ed. 61(13), e202200271 (2022). https://doi.org/10.1002/anie.202200271
  46. C. Shi, S.-H. Kim, N. Warren, N. Guo, X. Zhang et al., Hierarchically micro- and nanostructured polymer via crystallinity alteration for sustainable environmental cooling. Langmuir 40(38), 20195–20203 (2024). https://doi.org/10.1021/acs.langmuir.4c02567
  47. Q. Ye, N. Guo, M. Chen, Reversible solar heating and radiative cooling coupled with latent heat for self-adaptive thermoregulation. Appl. Phys. Lett. 126(11), 113903 (2025). https://doi.org/10.1063/5.0262028
Read More
Author biographies are not available.
Download this PDF file
PDF SUPPLEMENTARY FILE
Statistic
Read Counter : 1098 Download : 818