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 kappa- 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.