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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]

Superoleophilic graphene–nickel foam (PDMS–G–NF), which was prepared by coating graphene nanosheets onto nickel foam followed by surface modification with polydimethylsiloxane (PDMS), was used as porous supporting material to prepare form-stable phase change materials (PCMs) composites. Owing to the strong hydrophobic and superhydrophilic wettability of PDMS–G–NF, PCMs can be absorbed spontaneously into PDMS–G–NF and can stay stable without leakage even over their melting points. The incorporation of PCMs into PDMS–G–NF does not change the crystal structure but lowers the crystallinity size of PCMs in the composites, which is confirmed by X-ray powder diffraction (XRD) analysis. The latent heat of PDMS–G–NF/PCM composites was measured in the range of 42.3–123.41 kJ kg −1 . Taking advantages of the simple process and good stability the PDMS–G–NF should be ideal candidates as an alternative to traditional PCMs, which may have great potentials for renewable energy saving applications. [ABSTRACT FROM AUTHOR]

Solar-driven water evaporation is emerging as a promising strategy to utilize solar energy for the desalination and water purification. In this work, two kinds of monoliths based on hypercrosslinked polymers (HCPs) nanotubes, which were synthesized using inexpensive and conventional chemicals, i.e. benzene and methylbenzene as building blocks via Friedel-Crafts reaction, have been created as photothermal materials through a superhydrophilic modification followed by the coating of polypyrrole as light absorption layer. The as-synthesized HCPs possess large specific surface area (up to 773 m2 g-1) and low apparent density (0.011 g cm-3), which endow them very low thermal conductivity (0.029 W m-1 k-1). After modification with sodium alginate and polypyrrole, the resulting HCPs (named as PPy-M-HCPs) show surface superhydrophilicity (water contact angle ~0°), stronger light absorption (ca. 95%) and better mechanical properties. Taking advantages of these unique physicochemical properties mentioned above, the PPy-M-HCPs exhibit outstanding light-to-heat conversion performance with a high solar conversion efficiency of ca. 87% achieved under 1 kW m-2 irradiation. In addition, the PPy-M-HCPs also show excellent salt-resistant performance, e.g. a high energy conversion efficiency of more than 85% obtained in 20 wt% NaCl solution, due to their loosely porous structure coupling with their superhydrophilic wettability. Based on the merits of simple fabrication process, excellent stability and high solar conversion efficiency, the PPy-M-HCPs may have great potentials as efficient photothermal materials for real applications. The prepared PPy-M-HCPs photothermal materials possess superhydrophilicity, low thermal conductivity, broad light absorption, high energy conversion efficiency and excellent salt-resistant ability, providing the possibility for efficient solar steam generation. Image 1 • Hypercrosslinked polymers as photothermal materials for solar steam generation were prepared. • They possess high energy conversion efficiency more than 87% under 1 sun irradiation. • They have advantages of simple fabrication process and excellent stability. [ABSTRACT FROM AUTHOR]

With the increasing global instability in the development of the world, the efficient storage and conversion of energy have alerted attention. In this work, a novel conjugated microporous polymer hollow spheres (CMPHS) with a high specific surface (323 m2 g−1) and unique cavity structure are creatively prepared. By treatment with simple carbonization, the resulting carbonized microspheres (CCMPHS) show a high light absorption (80%) and outstanding thermal stability (thermal decomposition at 506 °C). On basis of the abundant micropores distributed on the surface of microspheres, the organic phase change materials (PCMs) i.e., fatty alcohols (tetradecanol (TD), hexadecanol (HD), and octadecanol (OD)), are successfully embedded into CCMPHS to afford a kind of new composite (CCMPHS@PCMs) for energy storage and conversion. The three kinds of CCMPHS@PCMs exhibit high latent heats (220.1 kJ kg−1, 244.6 kJ kg−1, and 228.8 kJ kg−1, respectively.). In terms of energy conversion, the photothermal conversion efficiencies of CCMPHS@PCMs are up to 86.83%, 89.45%, and 85.40% and the electrothermal conversion efficiencies are 83.81%, 81.10%, and 90.50%, which possess one of the highest values among the most of similar composites embed with PCMs reported to dates. Based on the advantages of simple fabrication, easy to scale up, high energy density, and conversion efficiency, the CCMPHS@PCMs are expected to be one of the most promising candidates as efficient PCMs composite for a variety of practical applications such as solar or electric energy harvesting, storage, conversion, and so on. • Hollow porous polymers spheres prepared by template method. • The CMPHS and CCMPHS exhibits unique nano spherical morphology, abundant porosity. • The CCMPHS shows excellent solar light absorption about 80% at the range of visible light and superior thermal stability which make decomposition at 506 °C. • The CCMPHS@PCMs possesses huge energy density, and storage/conversion potential which possess 90% photothermal conversion and thermoelectric conversion efficiency. • The CCMPHS@PCMs has great advantages for their simple and scalable manufacture process. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) composites are of great importance for a wide range of applications in energy conversion and storage, waste heat recovery and utilization, thermal energy management in building, electronic devices cooling and heat insulation, etc. Herein, a novel strategy for the fabrication of PCM composites for solar/electro energy conversion and storage is reported. The polypyrrole (PPy) coated conjugated microporous polymers/expanded graphene (EG) carbon aerogels/HDA (PCMPECAs/HDA) composites were firstly obtained via Sonogashira–Hagihara cross-coupling reaction followed by a carbonization treatment, PPy coating and finally 1-Hexadecylamine (HDA) impregnation. The introduction of EG and PPy was to improve the porosity, thermal conductivity and photothermal performance. The resultant PCMPECAs/HDA composites exhibited excellent comprehensive performances, including relatively high thermal conductivity of up to 234.0% that of HDA, high energy storage density up to 205.10 kJ/kg, excellent shape and thermal stability and a remarkable photothermal conversion and storage efficiency of up to 93.5%, respectively. And after 300 times thermal and cooling cycles, the latent heat of PCMPECAs/HDA still remains up to 150.20 kJ/kg. Besides, the resultant composites also manifest excellent electro-thermal effect at low voltage. Due to the aforementioned advantages, PCMPECAs/HDA composites possess great potential applications in solar/electric energy conversion and storage. • Conjugated microporous polymer carbon aerogels composites are first reported. • The latent heat of PCMPECAs/HDA composites were tested up to 205.10 kJ/kg • The resultant composites show an ultrahigh photothermal conversion efficiency (93.5%). • The shape-stable composite has a phase change enthalpy of 150.20 kJ kg-1 after 300 cycles. • The resultant composites presented an excellent electro-thermal effect at low voltage. [ABSTRACT FROM AUTHOR]

Solar-assisted steam generation is considered as an environmental-friendly and feasible technology to effectively harvest solar energy, which has been widely in water purification, seawater desalination and steam sterilization. In this work, we demonstrated flexible and scalable double-layered photothermal material (named as ppy-RF) based on phenolic aldehyde foam and polypyrrole coating as a light adsorption layer for solar steam generation. The resulting ppy-RF foam possessed interpenetrated and macroporous network with high porosity (>86%), superhydrophilicity, low thermal conductivity (0.0396 W m-1 K-1) and almost 100% absorbance (500-2500 nm). These characteristics make ppy-RF foam rapid water transportation and steam generation with an energy conversion efficiency of 90% under solar illumination of 1 kW h-1. Furthermore, the ppy-RF foam exhibits outstanding salt-resistant performance and long-term stability for desalination even in high salinity brine (20 wt%). By combination of its porous, flexible and monolithic configuration obtained by a simple and scalable fabrication method with efficient solar-thermal conversion ability and salt-resistance, the ppy-RF foam shows great potential in the application of clean water production and brine desalination. 1. Flexible and scalable double-layered photothermal phenolic aldehyde foam was developed. 2. The ppy-RF foam exhibits interpenetrated and macroporous network with high porosity. 3. The ppy-RF foam showed an energy conversion efficiency of 90% under 1 sun. 4. The ppy-RF foam exhibits high salt-resistant performance with long-term stability. [ABSTRACT FROM AUTHOR]

Solar-driven interface evaporation has received much attention due to its high-efficiency photothermal conversion efficiency. However, in practical application, it is difficult to monitor whether the evaporation efficiency of photothermal conversion materials can maintain high efficiency and stability for a long time. In this paper, taking surface modified coconut fiber (SCF) as photothermal material, we designed a set of evaporation efficiency monitoring device (EEMD) and demonstrated the strategy of building a solar evaporation efficiency monitoring system. The SCF shows superhydrophilic wettability, and its vertical multi-stage open-framework structure is benefit to the rapid transport of water. Under 1 kW m−2 illumination, evaporation rate of SCF is 1.5 kg m−2 h−1, evaporation efficiency is 90.2%. In 20% NaCl, evaporation rate of SCF is 1.37 kg m−2 h−1, and energy conversion efficiency is 85.3%. In order to monitor the stability of evaporator efficiency, we designed a simple EEMD which applied platinum wire electrode to monitor the change of electric potential in the evaporator. The results show that the electric potential is positively correlated with the evaporation efficiency. EEMD provides a new monitoring method for the efficient and stable operation of solar evaporator. We demonstrate for the first time a new strategy for monitoring the evaporation efficiency of photothermal materials of solar steam generators by evaporation efficiency monitoring device (EEMD). The findings obtained from this study may provide a simple and versatile way for the efficient and stable operation of solar evaporator. Image 1 • Evaporation Efficiency Monitoring Device (EEMD) was designed for solar steam generation. • EEMD provides a new monitoring method for the efficient and stable operation of solar evaporator. • The electric potential is positively correlated with the evaporation efficiency. [ABSTRACT FROM AUTHOR]

Solar steam generation is a kind of highly promising technology for harvesting solar energy and the production of fresh water. Here, we report the fabrication of a novel Ca2+ crosslinked sodium alginate modified monolithic polypyrrole 3-D conductively porous architecture (M-PPy sponge) with unique micron-sized channels as functional solar steam generator. The as-synthesized M-PPy sponge shows excellent thermal insulation (a low thermal conductivity of 0.0995 W m−1 k−1), superhydrophilicity, nearly 100% light absorption and better mechanical properties. Under a solar light power of 1 kW m−2, a higher evaporation efficiency of 84.72% was achieved, which is comparable to the best performance for polymer systems that have been reported so far. More significantly, the modified monolithic polypyrrole shows the excellent salt-resistant performance in high saline solution with the greater evaporation efficiency of 84.43% and recyclability, making it promising candidate for a variety of applications, including power generation, desalination and so on. M-PPy sponge with unique micron-sized channels was synthesized to have superhydrophilicity, high solar evaporation efficiency, excellent salt-resistant performance and recyclability, making it promising candidate with great potentials for efficient solar steam generation. Image 1 • Ca2+ crosslinked sodium alginate modified monolithic PPy sponge. • The PPy sponge exhibits micron-sized channels, low thermal conductivity, 99% light absorption. • It shows high solar evaporation efficiency, excellent salt-resistant performance and recyclability. [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]

Cost-effective and scalable solution to fabricate high-performance photothermal materials is the key to enable widespread application for solar steam generation. Herein, we report the facile and scalable fabrication of monolithic porous foam based on cross-linked aromatic polymer (PDVB-PS) using styrene as monomer and divinylbenzene as cross-linking agent through a facile one-step hydrothermal method. The resulting PDVB-PS foam possesses well-controlled porous structure, open channel structure, low apparent density and low thermal conductivity (0.038Wm−1k−1). After modification with sodium alginate and polypyrrole, the as-modified PDVB-PS (named as PPy-coated M-PDVB-PS) shows a superhydrophilic wettability (water contact angle ∼ 0°) and stronger light absorption (ca. 90%), which could dramatically enhance its water transportation ability and photothermal property. Taking advantages of these unique physicochemical properties mentioned above, a high solar-vapor conversion efficiency of 87.6% for the PPy-coated M-PDVB-PS was obtained under 1-sun irradiation, showing great potentials for real applications. More importantly, as a kind of representative synthetic polymers, the success in employment of the PPy-coated M-PDVB-PS as efficient photothermal materials shown in this study may also open a new opportunity for rational design and fabrication of polymer-based solar generators derived from commercial available low-cost raw chemicals with simple and scalable manufacture process for practical solar steam generation on large scale. • Monolithic porous foam (PDVB-PS) was first synthesized by a simple and scalable one-step hydrothermal method. • The PPy-coated M-PDVB-PS possesses open channel structure, low thermal conductivity and broad light absorption. • It shows an exceptionally high solar-vapor conversion efficiency of 87.6% under only 1-sun simulated solar irradiations. [ABSTRACT FROM AUTHOR]