Multi-source responsive and leakage-proof phase change composites based on cellulose nanofiber/sodium alginate crosslinked aerogel for thermal energy storage and management.

Solar energy, as a sustainable and clean energy source, has been extensively explored for diverse applications. Organic phase change materials (PCMs) offer a promising route for solar thermal energy storage; however, issues such as leakage, low thermal conductivity, and dependence on a single energy conversion pathway have hindered their practical deployment. In this study, a magnetic porous carbon aerogel was fabricated by integrating cellulose nanofibrils, sodium alginate, and MnFe2O₄-modified graphene (MGO). Polyethylene glycol (PEG) was subsequently adsorbed into the aerogel framework, yielding shape-stabilized phase change composites (PMCS). Benefiting from the interconnected three-dimensional porous network of the magnetic carbon aerogel, the resulting PMCS achieved a PEG loading of 94.54% and a melting enthalpy of 160.32 J/g. Moreover, the synergistic contributions of MGO and biocarbon to light absorption and electrical conductivity, together with the magnetic hysteresis of MnFe2O4 under an alternating magnetic field, endowed PMCS with efficient light-to-heat-to-electricity and magneto-thermal conversion capabilities. These multifunctional energy conversion properties significantly enhance overall energy utilization efficiency, demonstrating considerable potential for next-generation renewable energy storage and conversion systems.