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The development of high-performance form stable phase change materials (FSPCMs) with higher optical absorbance and phase change enthalpy is of great significance to building energy conservation. A kind of Ti 3 C 2 /pectin aerogels was prepared by self-assembly of pectin and MXene nanosheet (Ti 3 C 2) by solution blending method. These aerogels were directly dipped in the molten dodecylamine (DDA) as the phase change material. The results show that the PCM composites with 3 wt% Ti 3 C 2 have a phase change temperature of 25.47 °C (at which the human body feels comfortable), latent heat of phase change of 218.8 kJ kg−1, and thermal conductivity of 0.1817 W/(m K). The prepared FSPCMs have the characteristics of suitable phase change temperature, high latent heat, good melting/freezing cycle reliability, strong mechanical properties, significant photothermal energy conversion capacity (more than 92%), and good thermal insulation performance. Therefore, the corresponding pectin-based composites with better light absorption and mechanical properties are expected to have broad application prospects in energy conversion and building energy conservation. • Aerogels with enhanced mechanical properties were prepared by self-assembly of Ti3C2 and pectin. • The addition of Mxene effectively improved the solar-thermal conversion efficiency (92.6%) of composites. • The form-stable PCM composite has a phase change enthalpy of 196.3 kJ kg-1 (after 200 cycles). • The dodecylamine used in building energy storage has a suitable phase transition temperature (25.18 °C). [ABSTRACT FROM AUTHOR]

The development of high-performance shape-stable phase change materials composites (ss-PCMCs) with enhanced thermal conductivity and high phase change enthalpy is of great importance for thermal energy storage. Herein, we report the creation of novel ss-PCMCs by incorporation of organic PCMs (1-hexadecanamine (HDA) and palmitic acid (PA)) into the biomass carbon aerogels (BCAs refer to sunflower receptacle spongy carbon aerogel (r-CA) and sunflower stem carbon aerogel (s-CA)) through a simple vacuum infusion. Due to their abundant porosity, light weight and high specific surface area, organic PCMs can be spontaneously loaded into BCAs with an ultrahigh loading rate of up to 1988 wt%. The obtained of PCM/BCAs composites show high phase change enthalpy of ranging from 207.9 kJ kg−1 to 271 kJ kg−1, in addition to their excellent thermal stability and recyclability, e.g., their phase change enthalpy nearly remains unchanged even after 50 times of melting/freezing cycles. The PCM/BCAs composites also show an enhanced thermal conductivity. Furthermore, the light-to-thermal conversion efficiency was found to be promising candidates for light-to-thermal energy storage applications on basis of their 75.6% for HDA/r-CA and 67.8% for HDA/s-CA, respectively, making them abundant resource, cost-efficiency, simple and scalable fabrication process. • HDA was first exploited as a new class of phase change material. • ss-PCMCs were fabricated by doping of PCM into biomass carbon aerogels of sunflower. • The HDA/BCAs shows high light-thermal conversion efficiency (67.8%–75.6%). • The loading rate of HDA in BCAs is up to 1988 wt % and 873%, respectively. [ABSTRACT FROM AUTHOR]

The development of high-performance shape-stable phase change materials composites (ss-PCMCs) with enhanced thermal conductivity and high phase change enthalpy is of great importance for thermal energy storage. Herein, we report the creation of novel ss-PCMCs by incorporation of organic PCMs (1-hexadecanamine (HDA) and palmitic acid (PA)) into the biomass carbon aerogels (BCAs refer to sunflower receptacle spongy carbon aerogel (r-CA) and sunflower stem carbon aerogel (s-CA)) through a simple vacuum infusion. Due to their abundant porosity, light weight and high specific surface area, organic PCMs can be spontaneously loaded into BCAs with an ultrahigh loading rate of up to 1988 wt%. The obtained of PCM/BCAs composites show high phase change enthalpy of ranging from 207.9 kJ kg−1 to 271 kJ kg−1, in addition to their excellent thermal stability and recyclability, e.g., their phase change enthalpy nearly remains unchanged even after 50 times of melting/freezing cycles. The PCM/BCAs composites also show an enhanced thermal conductivity. Furthermore, the light-to-thermal conversion efficiency was found to be promising candidates for light-to-thermal energy storage applications on basis of their 75.6% for HDA/r-CA and 67.8% for HDA/s-CA, respectively, making them abundant resource, cost-efficiency, simple and scalable fabrication process. • HDA was first exploited as a new class of phase change material. • ss-PCMCs were fabricated by doping of PCM into biomass carbon aerogels of sunflower. • The HDA/BCAs shows high light-thermal conversion efficiency (67.8%–75.6%). • The loading rate of HDA in BCAs is up to 1988 wt % and 873%, respectively. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) have been widely used as efficient materials in latent heat thermal storage systems for various applications. The poor thermal conductivity of most organic phase change materials (OPCMs), however, has long been considered as one of big obstacles hindering their practical applications. Here, we report the first examples of Manganese dioxide nanowires and nanotubes based PCM nanocomposites (named as MnO 2 NWs/PCM and MnO 2 NTs/PCM) with enhanced thermal conductivity by simply using MnO 2 nanowires and nanotubes as efficient nanofillers. The PCMs nanocomposites show high latent heat ranging from 140.1 J g −1 to 206.1 J g −1 . The thermal conductivity of PCM nanocomposites were dramatically enhanced by incorporation of Manganese dioxide nanowires and nanotubes with a maximum value of 377.16% of that of pure PA achieved, which is nearly two times of that of control. X-ray diffraction (XRD) analysis shows that the incorporation of nanofillers does not change the crystalline structure of OPCMs while lowering its crystalline size. The PCM nanocomposites also show excellent thermal stability of recyclability. Only a slight loss of 2.8% in latent heat was observed after 100 times of melting/cooling cycles. Based on their high heat storage performance, excellent thermal conductivity and thermal stability of recyclability, the as-prepared PCM nanocomposites may have great potentials for energy saving applications. [ABSTRACT FROM AUTHOR]

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]

Herein, an approach for development of a novel FS-PCMCs by incorporation of FAs into the GCA, which was derived from one-step hydrothermal of C-MWCNTs and GO followed by annealing treatment, through a simple direct impregnation. The FS-PCMCs was developed for solar energy storage. [Display omitted] The exploitation of excellent performance form-stable phase change material composites (FS-PCMCs) with enhanced photothermal conversion efficiency and high phase change latent heat is of great significance for thermal energy storage. In this work, a new type of FS-PCMCs with superior light-to-thermal conversion performance were created by impregnation of organic phase change material (1-hexadecylamine (HDA) and 1-tetradecylamine (TDA)) into the graphene aerogel (GA) and all-carbon aerogel (GCA) through a simple direct infusion. The multiwalled carbon nanotubes (MWCNTs) are wound around the inner wall of the GA layer to form a three-dimensional (3D) porous network structure to support fatty amine (FAs), thus achieving shape stability before and after phase transition. Moreover, the FS-PCMCs has extremely high phase transition enthalpy (203.1–248 kJ·kg−1) and good recyclability. More importantly, due to the high absorbance of GCA, it can enhance its light absorption capacity and reduce thermal radiation. The light-to-thermal conversion efficiency of the FS-PCMCs is 72.36%-88.25%. Taking the improvement of the comprehensive properties of the FS-PCMCs, the results of this work may open up a way for rational design and preparation of high-performance FS-PCMCs with enhanced storage capacity and light-to-thermal conversion efficiency for the efficient utilization of solar energy. [ABSTRACT FROM AUTHOR]

[Display omitted] Phase change materials (PCMs) with ideal light-to-thermal conversion efficiency play an important role in solar energy storage and conversion. Hence, we report the fabrication of a novel composite PCMs (CPCMs) device based on ZnO nanorods deposited indium tin oxide (ITO) glass loading with fatty amines. ZnO nanorods were deposited on the ITO glass using a three-electrode electrodeposition method, and 1-Hexadecylamine (HDA) was loaded on the ITO glass via spin-coating, followed by spraying polypyrrole (ppy) on the surface of CPCM device to improve thermal conductivity and solar absorption. The as-prepared CPCM device exhibits excellent light-to-thermal conversion efficiency, achieving a high conversion efficiency of 90.2% obtained at 1sun owing to its high light absorption (80%), enhanced thermal conductivity (improved by 57.8%), and the unique vertical aligned nanorods structure which could significantly decrease tortuosity, thereby reducing thermal route and lowering thermal response time. Furthermore, the electro-to-thermal conversion efficiency of the CPCMs device has also been investigated and the results show that it can reach up to 69.8% under a low voltage of 5 V, indicating that the CPCM device has a high potential in the field of electro-to-thermal conversion. Based on the benefits listed above, the CPCM device may serve an ideal platform for a wide range of solar energy storage and conversion applications. [ABSTRACT FROM AUTHOR]

The fabrication of composite phase change material (CPCM) with splendid light-to-thermal conversion efficiency and enhanced thermal conductivity is of significance for solar energy storage and transition. Hence, we report the creation of a novel CPCM prepared by impregnating 1-hexadecanamine (HDA) into nickel foam (NF) bearing with carbon nanotubes (CNTs) nanoarray via simple vacuum impregnation for photothermal conversion. The NF bearing with CNTs nanoarray employed in this study show outstanding light absorption of higher than 97% originated from its vertical aligned CNTs nanoarray which makes it possible for trapping the light to the most extent. Moreover, the metal nature of NF coupled with the carbon nature of CNTs nanoarray endow it excellent thermal conductivity, e.g. the thermal conductivity of CPCM is improved by 46.3% compared to that of the pure HDA. Thanks to the high latent heat of HDA (240 J/g), the latent heat of the CPCM are measured to be 132.2 J/g. In addition, it shows excellent thermal stability, e.g. the latent heat of the CPCM remains nearly unchanged after 50 times of melting/freezing cycles. Beneficial from their outstanding light absorption, excellent thermal conductivity and high latent heat, the as-prepared CPCM is an ideal platform solar energy harvesting, storage and transition. Under 1sun irradiation, the light-to-thermal conversion efficiency of the CPCM was measured to be 80.10%. Moreover, we detected the temperature-time curve of the CPCM under 30 V voltage, the result show that the CPCM also has great potential in the electro-to-thermal conversion application. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of phase change materials (PCMs) with high energy density is of great importance for thermal or solar energy storage. Here, we report for the first time the exploitation of fatty amines (FAs) as a new family of organic PCMs with the latent heat in the range of 260–437 kJ kg−1, which is one of the highest values for organic PCMs reported to date. With low supercooling degree (<10 °C) and a phase transition temperature of 25.8–71.6 °C, FAs are particularly suitable for thermal or solar energy storage at ambient conditions. Based on the plentiful chemistry of amino groups of FAs, we also prepared form-stable PCMs composites with enhanced FAs uptake due to the strong electrostatic interaction between amino groups of FAs and –SO 3 H groups of supporting materials, providing a new and versatile route to the construction of FAs-based PCMs composites for renewable and sustainable energy saving systems. Image 1 • Fatty amines (FAs) were first exploited as a new class of phase change materials (PCMs). • FAs show extremely high latent heat in the range of 260–437 kJ kg−1. • It is the highest value for organic PCMs reported to date. • FAs show low supercooling degree (<10 °C) and phase transition temperature of 25.8–71.6 °C. • Form-stable PCMs composites with enhanced FAs uptake were also prepared. [ABSTRACT FROM AUTHOR]

• Fatty amines (FAs) were first exploited as a new class of phase change materials (PCMs). • Form-stable PCMs composites were fabricated by doping of FAs into graphene sponge (FAs/GS). • The FAs/GS shows exceptional high energy density and low supercooling degree. • The FAs/GS shows enhance thermal conductivity, thermal stability and recyclability. • A FAs loading rate of 10,660 wt% was achieved, which is highest value reported to date. The development of form-stable phase change materials (FSPCMs) with large latent heat, excellent thermal stability, and recyclability is essential for their practical applications for thermal or solar energy saving. Here, we first report the exploitation of fatty amines (FAs), in this case tetradecylamine (TDA) and octadecylamine (ODA), as novel organic phase change materials (PCMs) for fabrication of FSPCM composites with exceptional high energy density using porous 3D graphene sponge (GS) as porous supporting materials. The resulting fatty amines/graphene sponge composites (FAs/GS) show high latent heat of ranging from 293 kJ kg−1 to 303 kJ kg−1 and low supercooling degree of 7–9 °C. Surprisingly, it is found that the loading rate of these two FAs into GS is as high as 7063–10660 wt%, which is nearly three orders of magnitudes higher than that of most reported FSPCMs. In addition, compared with the FAs, the presence of GS results in an enhancement of thermal conductivity of FAs/GS. After 200 cycles of thermal cycling, the latent heat content of FAs/GS still remains as high as 93.34% (TDA/GS) and 93.83% (ODA/GS), implying an excellent thermal stability. Taking advantages of the merits mentioned above, the findings of this work would not only open a new way for exploiting the FAs as new high-performance organic PCMs, but also provide a possibility for construction of such FAs/GS with great potentials for real energy-saving applications based on their exceptional high energy density, low supercooling degree, unprecedented high loading value, excellent thermal stability and recycling capacity. [ABSTRACT FROM AUTHOR]