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In order to improve the energy storage and conversion efficiency of phase change materials, a mixed clay sponge (MCS) containing palygorskite (Pal) and Halloysite Nanotubes (HNTs) was successfully constructed by solution polymerization. Expanded graphite (EG) was used to enhance the overall thermal conductivity and carbonized MCS with EG (mark as EG-MCS, C-EG-MCS). A series of form stable phase change materials (FSPCMs) were prepared by using them as scaffolds and encapsulated organic phase-change material 1-Hexadecylamine (HDA) by direct impregnation. By means of SEM, TEM, FTIR, XRD, XPS, DSC, TG, etc., their microstructure, chemical compatibility and thermophysical properties were systematically studied. The DSC results demonstrate that PCM composites exhibit relatively high thermal energy storage density of 214.2 kJ kg−1, 237.5 kJ kg−1 and 239.2 kJ kg−1 respectively. The reliability test shows that the PCM composites retain shape stability and almost no leakage of HDA even after 200 thermal cycles. Compared with the pure component HDA, the thermal conductivity of the as-prepared C-EG-MCS-HDA was improved from 0.147 W m−1 K−1 to 0.667 W m−1 K−1 and EG-MCS-HDA was improved from 0.147 W m−1 K−1 to 0.454 W m−1 K−1 owing to the high thermal conductivity of EG (only 6 wt%). Besides, the light-thermal conversion efficiency of EG-MCS-HDA and C-EG-MCS-HDA is 74.6%, 80.8% respectively. Therefore, the fabricated FSPCMs with high latent heat, good melting/freezing cycles reliability and high thermal conductivity, remarkable light-thermal energy conversion ability which have a broad application prospect in energy conversion and storage devices. Unlabelled Image • 1-Hexadecanamine (HDA) was first exploited as a new class of organic PCMs. • Form-stable PCMs composites were fabricated based mixed clay sponge. • The as-prepared PCM composites exhibit high light-thermal conversion efficiency. [ABSTRACT FROM AUTHOR]

Renewable pectin and cost-effective palygorskite (Pal) were used as raw materials to prepare hierarchically porous carbonized aerogels. The addition of cations (Ca2+) initiates supramolecular bonding of chains in the polymer and enhances the performance of the aerogel. Unlike the previous fragile biomass porous materials, the carbonized aerogels prepared this time showed excellent mechanical properties, with a compressive strength of up to 0.4 MPa at 80% strain. Dodecylamine (DDA) was loaded into the carbonized aerogel by the melt dipping method to obtain a stable phase change material (PCM) with positive performance. Furthermore, the chemical structure, microstructure, thermal stability, mechanical properties, heat storage performance, and thermal conductivity of carbonized clay/pectin aerogels and those of as-prepared composite PCMs were determined by various characterization techniques. The results demonstrate that inexpensive supporting materials can effectively improve the shape stability and thermal conductivity of composite PCMs. Meanwhile, the composite PCMs possess suitable phase transition temperature, reliable photothermal energy storage capacity, and excellent shape stability. The energy storage capacity and reliability of those cost-effective carbon-based form stable phase change materials (FSPCMs) reveal their tremendous application potential in solar energy utilization. • Resourceful raw materials were prepared as support with a simple method. • Palygorskite enhances the shape stability of composite phase change material (PCM). • Carbonized aerogel has an excellent mechanical property (0.4 MPa at 80% strain). • The composite PCM has a phase change enthalpy of 161.8 kJ kg−1 (after 300 cycles). • The photothermal conversion efficiency of composite PCM enables reach up to 77.5%. [ABSTRACT FROM AUTHOR]