Bioinspired Reprocessable Dual Crosslinked Solid-Solid Phase Change Material for Solar-Assisted Thermal Energy Storage and Multi-Scenario Thermal Camouflage
Solar energy, a clean and abundant resource, can be stored as latent heat in solid-solid phase change materials (SSPCMs) and subsequently utilized, offering great potential for advancing passive thermal management technologies such as thermal camouflage. Conventional SSPCMs often require active heating for high-temperature conditions, leading to additional energy consumption. Moreover, their permanent crosslinked structures limit reprocessability and increase environmental burden. Herein, we present a lizard-skin-inspired, solar-thermal-responsive, and reprocessable SSPCM (FTSPCM) featuring a dual crosslinked structure composed of dynamic phenol–carbamate bonds and Fe3+@Tannic acid (TA) coordination. Polyethylene glycol (PEG) functions as the phase change segment, while TA introduces both reversible covalent crosslinking and photothermal responsiveness. The FTSPCM exhibits a high latent heat of 102.9 J g−1, excellent shape stability, and maintains its thermal performance after three reprocessing cycles at 120 °C. The Fe3+@TA coordination network enables strong near-infrared absorption and efficient solar-thermal conversion, achieving a surface temperature of 62 °C and a conversion efficiency of 96.85% under 2 Suns irradiation. This dual-function design allows the material to achieve passive thermal camouflage via latent heat release at low temperatures and solar-assisted photothermal heating at high temperatures. This work presents a sustainable strategy for developing reprocessable, solar-responsive SSPCMs, showcasing the distinctive advantages of tannic acid-derived polyphenol chemistry in constructing passive thermal management systems for energy-efficient thermal camouflage and solar-driven thermal energy storage.