Fe3O4-Functionalized κ-Carrageenan/Melanin Hybrid Aerogel-Supported Form-Stable Phase-Change Composites with Excellent Solar/Magnetic–Thermal Conversion Efficiency and Enhanced Thermal Conductivity

Impregnating organic phase-change materials (PCMs) into biomass-derived aerogels is regarded as one of the most effective and accessible approach to address the liquid leakage issues of solid–liquid PCMs. However, the inefficient solar–thermal conversion and low thermal conductivity still restrict the large-scaled applications of organic PCMs in solar utilization fields. Herein, novel form-stable PCM composites (CMPCM-Fe) with enhanced thermal conductivity and excellent solar- and magnetic-driven thermal energy conversion and storage efficiency were fabricated by impregnating n-docosane into Fe3O4-functionalized κ-carrageenan/melanin hybrid aerogels (CMA-Fe) through vacuum impregnation. CMA-Fe effectively supported n-docosane and prevented the leakage issue during the phase transition process owing to its strong surface tension and capillary force. CMPCM-Fe exhibited high encapsulated efficiency (88.9–94.6%), satisfactory thermal storage capacity (229.1–246.9 J/g), and excellent reversible stability. The introduction of Fe3O4 nanoparticles enhanced the thermal conductivity (55.3% increased) and solar–thermal conversion efficiency (up to 93.5%) of CMPCM-Fe and endowed it with excellent magnetic–thermal conversion capacity under an alternating magnetic field. The synthesized CMPCM-Fe possesses broad application prospect in mutiresponse thermal management.