Evolution and emerging applications of SiO2-Based radiative cooling materials: From spectral regulation to thermal management

Passive radiative cooling (PRC) provides an electricity-free strategy for thermal management by emitting heat to outer space through the atmospheric window (8–13 μm) while minimizing solar heat gain. Silicon dioxide (SiO 2 ) has emerged as a key material platform for PRC due to its low solar absorption, characteristic mid-infrared optical response associated with Si–O–Si lattice vibrations, chemical stability, and structural versatility. However, achieving high cooling performance requires rational structural design because dense SiO 2 alone cannot provide sufficient broadband solar reflection. This review summarizes the evolution of SiO 2 -based radiative cooling materials from spectral regulation to application-oriented thermal management. A three-tier design framework is proposed, including Tier 1 (Particle Engineering), Tier 2 (Structural Engineering), transitional hybrid functional systems between Tier 2 and Tier 3, and Tier 3 (Integrated Functional Systems), highlighting the transition from optical optimization toward multifunctional thermal management. Representative strategies, including porous structures, photonic architectures, core–shell systems, polymer composites, and intrinsically functionalized structures, are discussed from the perspective of structure–property relationships. Furthermore, application-specific requirements, challenges, and opportunities are analyzed for wearable thermal management, built-environment solar thermal management, photovoltaic thermal management, and extreme-environment thermal management. Future directions, including AI-assisted material design, adaptive multifunctional systems, scalable manufacturing, and sustainable development, are highlighted. This review provides an evolutionary framework for understanding SiO 2 -based radiative cooling materials and guides the development of scalable, application-oriented thermal management technologies.