All-Ceramic, compressible and scalable nanofibrous aerogels for subambient daytime radiative cooling

Li, Tao; Sun, Haoyang; Yang, Meng; Zhang, Chentao; Lv, Sha; Li, Bin; Chen, Longhao; Sun, Dazhi

doi:10.1016/j.cej.2022.139518

Cited by 33 publications

(20 citation statements)

References 46 publications

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“…Existing studies have shown that rod-like or fibrous microstructure can increase the backscattering of sunlight. , Interestingly, the rod-like structures are very common in the β-Si 3 N 4 crystals. Moreover, Si 3 N 4 possesses a wide band gap (5.1 eV) and high refractive index (2.1), which not only avoids the absorption of sunlight but also increases the optical impedance mismatch at the interface with air, thus leading to a high theoretical solar reflectivity.…”

Section: Resultsmentioning

confidence: 99%

Structural Porous Ceramic for Efficient Daytime Subambient Radiative Cooling

Zhao,

Meng,

et al. 2023

ACS Appl. Mater. Interfaces

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Radiative cooling enables the passive cooling of buildings without energy input. Structural radiative cooling materials, such as cellulose-based composites, have recently received extensive attention due to their exceptional mechanical properties and spectral selectivity. However, the cellulose-based materials face challenges in durability and flame resistance, which limits their practical application. Herein, a structural porous Si3N4–BN ceramic with a high solar reflectivity of ∼0.95 and an atmospheric window emissivity of ∼0.95 was prepared by one-step combustion synthesis. The porous ceramic achieves a subambient radiative cooling performance of 5.14 °C under direct sunlight and theoretically yields a cooling power of 78.55 W m–2. The network structure of Si3N4 crystals leads to a flexural strength of 31.07 MPa and a compressive strength of 65.36 MPa. The porous Si3N4–BN ceramics with excellent radiative cooling performance, mechanical properties, and thermal insulation exhibit wide application prospects in building cooling, especially in the harsh environment of tropical desert and island regions.

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Section: Resultsmentioning

confidence: 99%

Structural Porous Ceramic for Efficient Daytime Subambient Radiative Cooling

Zhao,

Meng,

et al. 2023

ACS Appl. Mater. Interfaces

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“…One example of ceramics used for RC is offered by ref (Figure ). Their nanofibrous aerogels (SAFAs) synthesized by electrospinning provide a high solar reflectance of ∼95% and a high atmospheric window emissivity of ∼93% because of the scattering reflection and selective emission of the fiber network in aerogel.…”

Section: Ceramicsmentioning

confidence: 99%

Section: Ceramicsmentioning

confidence: 99%

A Perspective for Radiative Cooling Materials

Boretti¹

2023

ACS Appl. Opt. Mater.

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Radiative cooling (RC) is a technique that allows objects to cool down by radiating heat to cold outer space, even during the daytime. Different materials offer unique opportunities and face distinct challenges when used for RC applications. Understanding these characteristics helps in selecting the most suitable materials for specific cooling requirements, taking into account factors such as thermal stability, emissivity, fabrication techniques, and cost-effectiveness. The various materials which have been explored for RC applications have their own set of challenges and opportunities, specific to the application, which are here discussed.

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“…Passive radiative cooling (PRC) has proven to be a promising electricity-free cooling strategy for dissipating heat of terrestrial objects through the atmospheric transparency window (8-13 μm) [1][2][3][4][5], and have attracted much attention for its potential of mitigating global warming [6] and the urban heat island effect [7,8]. Sub-ambient daytime cooling applications under 3 direct sunlight illumination is particularly attractive and challenging to achieve [9][10][11]. In fact, this requires materials that are engineered to exhibit high reflectivity (>95%) over the whole solar spectrum, combined with a high thermal emission capacity in the atmospheric transparency window [12,13].…”

Section: Introductionmentioning

confidence: 99%