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The development of phase change materials (PCMs) composites with high light‐to‐thermal energy conversion efficiency is of great importance for solar energy storage. Herein, the preparation of novel PCMs composites by incorporation of fatty amines (FAs) into the carbon membranes (CMs) with aligned nanochannels network is first reported, which is obtained by employing an anodic alumina oxidation membrane as sacrificing template and using polypyrrole and asphalt as carbon precursor via a simple carbonization treatment. The carbonized membranes possess abundant porosity and aligned nanochannels, which is beneficial to harvest solar light combined with their carbon in nature. In addition, organic PCMs, i.e. 1‐Hexadecanamine (HDA, ΔH = 311.1 kJ/kg) and 1‐Aminoheptadecane (AHD, ΔH = 293.0 kJ/kg) can be spontaneously loaded into the nanochannels of CMs by the capillary action and surface tension. The fabricated FAs/CMs composites present an enhanced thermal conductivity ranging from 0.291 to 0.525 W m−1 K−1. Compared to pure FAs, the thermal conductivities of the PCMs composites are 144.8–357.1% higher than that of the control. Meanwhile, the as‐synthesized FAs/CMs composites also exhibit a remarkable high photothermal energy storage efficiency of up to 93.8%, which is one of the highest values reported to date, making them promising candidates for a broad range of applications in solar energy harvesting, conversion, and storage. [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]

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]

Spongy carbon soot (s‐CS) was prepared and used as novel host material of the form‐stable composite phase change materials (PCMs). The s‐CS was constructed by the interconnected and compact large agglomerates of the soot particles with an average size of 25–60 nm. The average pore diameter of the s‐CS was measured to be 15.3 nm. Owing to capillary forces of s‐CS, n‐carboxylic acids can be easily absorbed into the pores and stay stable without leakage. The PCMs/s‐CS composite present a high heat storage capacity between 83.42 J g−1 and 99.63 J g−1, corresponding to the mass fraction of n‐carboxylic acids between 50.10% and 53.20%. The effects of the supporting material on thermal stability and thermal conductivity of composites were investigated by means of thermogravimetry and flash thermal conductivity testing. The PCM/spongy CS composites exhibit excellent thermal stability and durability, and may have great potential for renewable 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]

Thermal management of wearable electronics integrated with biological tissues remains one of the critical challenges for their practical applications. The undesired heating can cause thermal discomfort or even thermal damage to biological tissues. Here, a novel thermal protecting substrate design is proposed for wearable electronics with abilities to manipulate the heat flow and efficiently absorb the excessive heat energy without the compromise of substrate flexibility. The thermal protecting substrate features a functional soft composite, which incorporates the embedded phase change material with a thin metal film on the top in a soft polymer. Compared with conventional substrate, the proposed thermal protecting substrate can reduce the peak temperature increase by over 85% with appropriate parameters. Experimental and numerical studies reveal the fundamental aspects of the design and operation of functional soft composite to effectively avoid excessive heating of biological tissues. Influences of geometrical parameters on temperature reduction are investigated. Device demonstration of thermal protecting substrate in a wearable heater on pig skin illustrates the unusual capability to reduce the maximum skin temperature, thereby enabling practical applications of wearable electronics and creating engineering opportunities in biointegrated applications requiring thermal protection of biological tissues. [ABSTRACT FROM AUTHOR]

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 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]

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]

The construction of high-performance materials with superior light-to-thermal conversion efficiency is of great importance for harvesting and utilization of solar energy. Hence, we report the creation of novel composite phase change materials (CPCMs) CPCMs by incorporating three kinds of organic phase change materials (PCMs), i.e. 1-Tetradecylamine (TDA), 1-hexadecanamine (HDA) and Octadecylamine (ODA), into hollow carbon nanospheres (HCNS) via a simple impregnation treatment for efficient light-to-thermal transition. Owing to their carbon in nature, the HCNS show better light absorption of higher than 90%. After incorporation of organic PCMs, their light absorption could still attain 62–70%, which can compete with the existing CPCMs. Beneficial from their abundant porosity and high specific surface areas, organic PCMs can be spontaneously diffused and immersed into the porous architecture of HCNS. In this way, the as-resulted CPCMs containing with TDA, HDA and ODA show high phase change enthalpy of 61.23J/g, 119.5J/g and 101.8J/g, respectively. The CPCMs also exhibit better thermal conductivity and excellent thermal stability, e.g., the enthalpy of HAD based CPCMs remains nearly unchanged even after 100 times of melting/freezing cycles. Under 1 sun irradiation, the light-to-thermal conversion efficiency of CPCMs containing with TDA, HDA and ODA were measured to be 73.04%, 74.46% and 71.74%, respectively, Thus showing great potential as a kind of promising photothermal conversion devices for solar or thermal energy storage applications. • A novel CPCMs was fabricated to improve light-to-thermal conversion efficiency. • The CPCMs can harvest and transfer visible light efficiently. • The CPCMs own excellent thermal stability and enhanced thermal conductivity. [ABSTRACT FROM AUTHOR]