Global warming intensifies heat stress, posing substantial challenges to cultivated plants and agricultural yield production. The high solar absorptance of soil results in elevated temperatures, pushing plants beyond their ideal growth range. Additionally, this rise in soil temperature accelerates soil moisture evaporation, further aggravating existing water scarcity issues. Common cooling solutions tends to consume significant amounts of water or offer limited cooling capacities. In response, a radiative cooling and moisturizing film composed of biodegradable ethyl-cellulose was developed. With a solar reflectance of 97% and a thermal emissivity of 0.93, this film provides efficient zero-energy cooling for soil surfaces. Field tests have demonstrated that compared to commercial cooling mulch, the radiative cooling film significantly reduces soil temperature and moisture evaporation by 50% and 60%, respectively. Furthermore, it boosts plant growth by 30% by moderating leaf temperatures and augmenting the exposure to reflected sunlight, crucial for photosynthesis on hot days. Global heat-water simulations reveal that the film increases soil moisture preservation by over 80% and alleviates agricultural water scarcity by over 60% in arid regions during hot seasons. This work offers a practical and sustainable solution to mitigate heat stress and promote resilient cultivation practices in the context of global warming.

A photo- and electro-thermal film can convert sunlight and electricity into heat to solve icing problems. Combination of them provides an efficient strategy for all-day anti-/de-icing. However, only opaque surfaces have been reported, due to the mutual exclusiveness between photon absorption and transmission. Herein, a highly transparent and scalable solution-processed photo-electro-thermal film is reported, which exhibits an ultra-broadband selective spectrum to separate the visible light from sunlight and a countertrend suppress of emission in longer wavelength. It absorbs ≈ 85% of invisible sunlight (ultraviolet and near-infrared) for light-heat conversion, meanwhile maintains luminous transmittance > 70%. The reflection of mid-infrared leads to low emissivity (0.41), which further preserves heat on the surface for anti-/de-icing purpose. This ultra-broadband selectivity enables temperature elevation > 40 °C under 1-sun illumination and the mutual support between photo-thermal and electro-thermal effects contributes to > 50% saving of electrical consumption under weak solar exposure (0.4-sun) for maintaining unfrozen surfaces at -35 °C environment. The reverberation from photo-electro-thermal and super-hydrophobic effects illustrates a lubricating removal of grown ice in short time (< 120 s). The self-cleaning ability and the durability under mechanical, electrical, optical, and thermal stresses render the film stable for long-term usage in all-day anti-/de-icing applications.

Abstract Agriculture faces pressing challenges of heat stress and water scarcity due to climate change. While mulching is a common solution, traditional mulching materials lack sub-ambient cooling capabilities and biodegradability, resulting in elevated soil temperature, increased moisture evaporation, exacerbated global agricultural heat-water crisis, and soil microplastics pollution. Herein, we have developed a biodegradable and biocompatible ethyl-cellulose radiative cooling mulch with a solar reflectance and thermal emissivity of 97% and 0.93, respectively, to provide zero-energy cooling for soil surfaces. Field tests have demonstrated that the radiative cooling mulch significantly reduces soil moisture evaporation by 60% through cooling soil surfaces, while also improves plant growth by 30% through reducing crop leaf temperature and increasing sunlight exposure for photosynthesis in hot days. Moreover, global heat-water nexus simulations show that the mulch increases soil moisture preservation by over 80% and alleviates agricultural water scarcity by over 60% in arid regions during hot seasons. The work offers an eco-friendly and feasible pathway to foster sustainable agriculture by alleviating heat stress and water scarcity in the context of global warming.

Superhydrophobic surfaces have attracted considerable attention because of their unique characteristics for widespread applications such as self-cleaning, de-icing, anti-fouling and drag reduction. However, previous research has failed to attain the required mechanical and chemical robustness simultaneously on a superhydrophobic surface, which has significantly limited its application in complex and practical scenarios. In this work, we have designed and fabricated a mechanically and chemically robust superhydrophobic surface with a high water contact angle of 160.1° and a low sliding angle of 2.7°. We achieved this through laser ablation to obtain micro-structured stainless steel frames, followed by filling nano-scale fluoropolymer internal coatings. Here the stainless steel protective frames have significantly enhanced mechanical durability of the surface and the fluoropolymer coatings have improved chemical corrosion resistance due to intrinsic chemical inertness. Thus, the synergetic effect of mechanical protective structures and chemical inertness allows the superhydrophobic surface to maintain superhydrophobicity even after sandpaper abrasion and chemical immersion. In addition, our superhydrophobic surface has exhibited potential for outdoor applications after performing well for 30-day tests under UV and thermal exposure, salt spray, and seawater immersion. We envision that such superhydrophobic surfaces with their superior mechanical robustness, chemical corrosion resistance, and scalable manufacturability are capable of expanding their operational lifespan in real-world applications.