Oriented cellulose scaffold-based carbonized wood-supported phase change materials with stable morphology and high thermal energy conversion efficiency

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Phase change materials are essential for sustainable thermal management, but challenges such as leakage, formability loss, low thermal conductivity , and poor photo-thermal conversion efficiency limit their stability and versatility. Herein, we propose a simple yet effective carbonization strategy that leverages the inherent three-dimensional, oriented, and hierarchical cellulose skeleton of carbonized wood (CW) to support polyethylene glycol (PEG). When the carbonization temperature is 1000 °C and the heating rate is 3–5 °C/min, the CW's maximum specific surface area and average pore diameter reach as high as 598.19 m 2 /g and 3.25 nm, respectively. Furthermore, the thermal conductivity of the CW-PEG composite phase change energy storage materials (CW-PEG composite PCESMs) increases to 0.434 W/m·K. The CW-PEG composite PCESMs exhibit a melting enthalpy of 130.5 J/g and an energy storage efficiency of 99.8 %. The surface temperature variations captured by the infrared camera during the heating and cooling cycles underscore the outstanding solar energy conversion efficiency of CW-PEG composite PCESMs. Moreover, even after 50 cycles, the phase change enthalpy retains 95 %, highlighting the CW-PEG composite PCESMs promising potential for energy-efficient building materials and cold chain transportation.