Flexible Aerogels for Thermal Management: Energy-Regulation Pathways, Performance Trade-Offs, and Design Strategies

Flexible aerogels, with highly porous architectures and tunable thermal, spectral, and electrical properties, have emerged as promising platforms for multifunctional thermal management. The functions, including thermal insulation, radiative cooling, photothermal and electrothermal heating, and thermal buffering, are enabled by energy regulation pathways for heat transfer suppression, solar rejection and radiative dissipation, energy conversion, and heat storage and release. More importantly, the distinctive advantage of flexible aerogels lies in their ability to preserve the structural basis that sustains these pathways under mechanical loading. This review presents an energy-flow-centered framework that connects functional properties, stable energy-regulation pathways, design strategies, and application-level functions. We first introduce the measurable thermal, spectral, electrical, and storage properties of aerogels and then examine the mechanical stability of their corresponding pathways. Then, design principles, trade-offs, and construction strategies of flexible aerogels are discussed in terms of preserving functional structures under deformation. Recent advances are critically compared, with emphasis on functional-mechanical coupling, performance retention, and application-specific trade-offs. Finally, we highlight key challenges and future directions, emphasizing the need to balance mechanical adaptability, durability, and multifunctional efficacy in next-generation flexible aerogels.