Passive daytime radiative cooling (PDRC) is an emerging energy-free cooling technology, which can weaken our dependence on energy-consuming air-conditioning requirements. Though the advance in micro/nanostructure PDRC materials achieves excellent sub-ambient cooling performance, the majority of them are facing a huge challenge in terms of practical large-scale applications owing to complicated preparation methods and high costs. Herein, combining a low-cost polymer matrix with inorganic dielectric particles, a hierarchically porous composite (HPC) film with a micro/nanostructure and adjustable spectral properties is developed through a flexible phase-inversion-based method. The HPC-film exhibits a strong solar reflectivity (∼98.26%) and infrared emissivity (∼97.56%), thus realizing a sub-ambient average cooling temperature of ∼9.1 °C and effective radiative cooling power of ∼87.2 W m⁻² under a solar irradiance of ∼890 W m⁻². As a proof of concept, we demonstrate that the proposed cooler is capable of delaying ice melting by four times compared with the pristine case due to the remarkable radiative cooling performance, which provides inspiration for developing a scalable and sustainable pathway of ice protection and preservation. Overall, the multiple advantages of the facile and flexible manufacturing technique, excellent stability and repeatability in this study promise potentially valuable applications in passive radiative cooling.

With the increasing development of photothermal techniques in various fields, particularly concentrated solar power (CSP) systems and solar thermoelectric generators (STEGs), the demand for high-performance spectrally selective absorbers (SSAs) has grown significantly. These SSAs are essential in achieving high solar absorption and minimal infrared thermal loss, thereby significantly enhancing solar utilization efficiency. This need becomes particularly critical in CSP systems, where high temperatures are pivotal for improved efficiency. However, the necessity for high temperatures imposes stringent requirements on the fabrication of SSAs, given the inherent trade-off between optical performance and thermal stability. SSAs typically require nanoscale thin films, but they are prone to oxidation and diffusion at high temperatures. Recent developments in photothermal materials, including ceramic composites, MXenes, high-entropy materials, and graphene, offer promising solutions to enhance SSAs’ performance. This review article provides a comprehensive evaluation of the latest advancements in these emerging photothermal materials. We summarize the strategies for integrating these advanced materials with already established nanostructures, which is a highly promising approach for the development of advanced SSAs. Additionally, the review explores the application of SSAs in CSP systems and STEGs to boost power generation efficiency. We conclude by summarizing the challenges and opportunities in the field of high-temperature SSAs, offering valuable insights into the development of high-performance SSAs and their role in solar-thermal power generation systems.

Ice loss from glaciers and snowpacks poses a growing threat to freshwater resources and coastal communities through sea-level rise, while also placing unprecedented demands on global cold-chain logistics.

This review provides a comprehensive overview of the evolution of spectrally selective absorber coatings, tracing developments from conventional metal nitrides to state-of-the-art high-entropy nitrides.