Structural Design and Energy Management Performance of Photothermal Phase Change Composites

Photothermal phase change composites have garnered extensive attention in solar energy conversion and storage. The performance, including photothermal conversion, phase change heat storage, and thermal conduction, depends critically on their multiscale structural design-from the nanoscale to the macroscale. This review summarizes the structural design principles for photothermal phase change composites, including photoresponsive isomer, continuous thermal networks, core-shell/layered heterostructures, gradient functional layouts, and bioinspired hierarchical architectures, etc. It elucidates how these structures regulate light absorption, heat storage, and heat transport behaviors in a synergistic manner. The discussion focuses on composite systems that integrate carbon-based scaffolds, porous inorganic supports, phase change materials (PCMs), and molecular solar thermal fuels (STFs), covering their fabrication approaches and performance optimization mechanisms. Representative applications in solar energy utilization, building energy efficiency, electronic thermal management, and flexible wearable systems are reviewed comprehensively. Finally, the review addresses key challenges-including structural stability, scalable manufacturing, and multifunctional integration-and outlines future directions toward intelligent, sustainable, and system-level solutions. This work provides a theoretical foundation and practical guidance for the design of high-performance photothermal phase change composites.