Elevating Solar-Thermal Conversion of Reprocessed Phase Change Materials Simultaneously toward Efficient Energy Storage and Self-Healing

To alleviate the resource shortage and environmental pollution, utilizing abundant solar energy effectively is a great challenge. In this article, a solar-thermal conversion material, Fe₂O₃-rGO, is integrated into the matrix of recyclable solid–solid phase change materials (RSSPCMs) to prepare solar-thermal conversion phase change materials, termed Fe₂O₃-rGO@RSSPCMs. The designed Fe₂O₃-rGO@RSSPCMs dexterously combine the solar-thermal conversion capability of Fe₂O₃-rGO with the thermal energy storage capability of RSSPCMs. Fe₂O₃-rGO@RSSPCMs exhibit a high latent heat of melting, reaching up to 108.58 J·g^–1, and demonstrate significant thermal storage capacity, along with excellent solar-thermal conversion efficiency. Notably, the introduction of Fe₂O₃-rGO into the molecular structure, activated by simulated sunlight, endows Fe₂O₃-rGO@RSSPCMs with remarkable self-healing properties and recyclability. Broken Fe₂O₃-rGO@RSSPCMs can be healed within 480 s under simulated sunlight irradiation (300 mW·cm^–2). Crucially, the structure, phase change behavior, and thermal stability of Fe₂O₃-rGO@RSSPCMs remain largely unchanged, even after multiple cycles. The design of Fe₂O₃-rGO@RSSPCMs is of considerable significance for achieving efficient solar energy utilization and promoting environmental protection.