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Thermal energy storage is important for energy saving and social developing. Low-cost, high thermal conductivity, form-stable composite phase change materials are urgent in energy storage and management. In this work, a novel carbonized wood-based composite phase change materials (TDCW) are fabricated by impregnating of 1-tetradecanol (TD) into carbonized wood (CW). CW as supporting material exhibits porous three-dimensional (3D) structure, high specific surface area and high thermal conductivity. In addition, compared with conventional graphene, carbon nanotubes and other one-dimensional (1D) or two-dimensional (2D) carbon materials, CW is inexpensive and has higher loading content of 73.4 wt%. What's more, CW as supporting material is firstly used in composite phase change materials. According to differential scanning calorimetry measurement and thermogravimetric analysis, TDCW possesses high latent heat, good thermal reliability and favorable thermal stability. In addition, thermal conductivities of PW, CW, TDCW measured at axial direction are all higher than that at radial direction and the thermal conductivity of TDCW is 0.669 Wm −1 K −1  at axial direction at 50 °C, which is 114% higher than that of pure TD. The results of thermal conductivity and surface temperature variation collected by infrared thermal camera under heating and cooling process demonstrate that TDCW is beneficial for thermal management application. This work not only provides a novel and superior supporting material, but also prepares a suitable phase change temperature, high latent heat and high thermal conductivity composite phase change material for thermal energy storage and management civil applications. [ABSTRACT FROM AUTHOR]

Fluorescent thermochromic wood-based composite phase change materials based on aggregation-induced emission carbon dots possessed effective solar-thermal conversion, storage and visual color change under solar radiation, especially as replacements for energy-saving buildings and optical lighting materials with thermal regulation capability. [Display omitted] • The WPCMs include DW, PEG and AIE-CDs. • The AIE-CDs are used as thermochromic and photothermal components in WPCMs. • The WPCMs possesses great solar-thermal energy conversion and storage capacity. • The WPCMs visibly shows solar-thermal energy storage and release processes by fluorescence color change. • The WPCMs are simulatively used as thermal regulation and fluorescent thermochromic building materials. Efficient solar-thermal energy conversion and storage is significant to overcome current energy shortage problems. Monitoring solar-thermal energy storage process by an evident and convenient display is conducive to improving energy utilization. Herein, fluorescent thermochromic wood-based composite phase change materials (WPCMs) were constructed for visual solar-thermal energy conversion and storage. It was fabricated by encapsulating polyethylene glycol (PEG) and aggregation-induced emission carbon dots (AIE-CDs) showing blue dispersed emission and red aggregation-induced emission into delignified wood (DW). The DW well-preserved the distinctive anisotropic porous structure and prevented the leakage problem of PEG. The WPCMs possessed great solar-thermal conversion capacity benefitting from strong and broad solar light absorption behaviors of AIE-CDs. Additionally, WPCMs showed real-time and visual fluorescent thermochromic property, it exhibited red AIE, and the fluorescence (FL) decreased and shifted into the blue emission band under solar radiation. The solar-thermal energy conversion and storage led to solid–liquid transformation of WPCMs, which promoted AIE-CDs' dispersion, thereby changing the FL. It also exhibited a high latent heat of fusion (160.8 J·g−1), favorable stability over 150 heating–cooling cycles, thermal stability below 210 °C and good shape stability. The WPCMs can be extended to applications in energy-saving buildings and optical lighting materials with visual thermal regulation capability. [ABSTRACT FROM AUTHOR]

Materials for energy collection, conversion and storage are important for overcoming energy-shortage problems. The research reported a nanocomposite containing polyethylene-glycol-10000 (PEG10000) as phase-change-material composite (PCMC) and graphene nanosheets functionalized with Fe 3 O 4 nanoparticles (Fe 3 O 4 -GNS) stored and loaded into a porous carbonized-wood-flour (CWF) matrix. The Fe 3 O 4 -GNS/CWF/PCMC nanocomposite possessed favorable photothermal and magnetocaloric conversion properties. Introducing Fe 3 O 4 -GNS and CWF enhances the inherently low thermal conductivity of the PCMC. Energy was stored by the PCMC and released during the phase transition process. Furthermore, additional magnetothermal conversion and storage via Fe 3 O 4 -GNS component could reversely promote photothermal conversion due to continuous thermal energy supply. PEG10000 as biocompatible and nontoxic PCMC could form efficient combination within Fe 3 O 4 -GNS/CWF/PCMC and conduct least environmental-related effect. The nanocomposite exhibited favorable thermal conversion performance as temperature rising over 65 °C within 150 s, excellent thermal stability below 300 °C, a high melting enthalpy over 95 J/g and crystallization enthalpy over 85 J/g, good stability over 100 heating-cooling cycles, and efficient synergetic energy conversion. The PCMC with Fe 3 O 4 -GNS adsorbed in CWF rapidly converted light and magnetic energy to thermal energy, because of the enhanced thermal conductivity. The Fe 3 O 4 -GNS/CWF/PCMC nanocomposite therefore would have great potential in energy collecting, conversion and storage applications. • Magnetocaloric-assisted photothermal conversion and storage process. • Biomass-derived and environmental materials function as function component. • Thermal conducting enhancement and energy conversion promotion. • High melting enthalpy over 95 J/g, crystallization enthalpy over 85 J/g of samples. • Fast thermal conducting with thermal conductivity up to 0.225 W (m K)−1 of samples. [ABSTRACT FROM AUTHOR]

• The composites own superhydrophobicity and thermal energy storage capacity. • The composites further prevent liquid leakage of TD in humid environment. • The composites could improve energy storage capacity in humid environment. • The composites with self-cleaning have efficient solar-to-thermal energy storage. Form-stable composite phase change materials, as thermal energy storage technology, show great promise for reducing energy consumption and relieving current energy shortage problems. However, porous supporting material s and most phase change materials are hydrophilic and hygroscopic, which cause crack-formation at the interfaces between supporting material s and phase change materials and decrease in thermal energy storage capacity of composite phase change material in wet or humid environment. There are almost no reports concerning this topic. Herein, form-stable and superhydrophobic composite phase change materials are fabricated by spraying superhydrophobic coating on the surface of composite phase change materials, in which delignified wood acts as a supporting material to protect against liquid leakage of 1-tetradecanol. The superhydrophobic composite phase change materials possess large water contact angle of 155° and superhydrophobic stability at 20–100 °C and pH 3–12, which prevents supporting material s and phase change materials from contacting with moisture in wet environment. In addition, the superhydrophobic composite phase change materials exhibit large latent heat of fusion (125.40 J/g), 29.58 J/g higher than that of composite phase change materials without superhydrophobic coating in wet environment. Moreover, the superhydrophobic composite phase change materials possess excellent thermal reliability and stability, efficient solar-to-thermal energy conversion and self-cleaning property, which are potential in the application of advanced energy-related devices and systems for thermal energy storage in wet or humid environment. [ABSTRACT FROM AUTHOR]

• Balsa wood as supporting material has high loading content of PCMs over 80%. • The composites have high energy storage capacity and good thermal reliability. • The composites exhibit excellent magnetic property and magnetothermal effect. • The addition of Fe 3 O 4 improves the solar-to-thermal conversion efficiency. In recent years, multifunctional form-stable composite phase change materials have been the research focus in the field of thermal energy storage. In this work, magnetic wood-based composite phase change materials are prepared via the impregnation of a compound of 1-tetradecanol and Fe 3 O 4 nanoparticles into delignified balsa wood. Delignified balsa wood, which has porous structure with low density and high loading content of over 80%, was used as a supporting material. The addition of Fe 3 O 4 nanoparticles provides an excellent magnetic property and improves the solar-to-thermal conversion efficiency of the composite. Benefiting from the magnetothermal effect, the magnetic wood-based composite phase change materials can be heated under an alternating magnetic field. Also, the magnetic wood-based composite phase change materials exhibit large latent heat (179 J/g), excellent thermal reliability after 100 heating-cooling cycles, and outstanding shape stability. And they have good thermal stability below 112 ℃. Considering the easy processing and excellent property, the magnetic wood-based composite phase change materials have great prospect in multifunctional thermal energy storage in practical applications. [ABSTRACT FROM AUTHOR]