Enhancing thermal conductivity and photothermal conversion of wood-based phase change materials through carbon-doped boron nitride incorporation

Wood-based phase change material composites are widely utilized in building materials due to their sustainability and environmental benefits. However, their inherently low thermal conductivity limits their effectiveness in thermal energy storage and conversion. To overcome this limitation, this study proposes an innovative strategy by incorporating carbon-doped boron nitride (BCN) and polyethylene glycol (PEG2000) into delignified wood (DW) to fabricate a novel composite phase change material (BCN-DW/PEG). The BCN is synthesized using glucose and hexagonal boron nitride (h-BN). This strategy effectively improves thermal conductivity while preserving the material's excellent phase change energy storage capability. The thermal conductivity of BCN-DW/PEG reaches 0.371 W/(m·K), exhibiting a 106% increase compared to DW/PEG. Additionally, the composite retains a high latent heat storage capacity of 187.5 J/g due to the efficient integration of PEG2000. Furthermore, BCN-DW/PEG demonstrates remarkable solar-thermal conversion performance, reaching 85 °C within 250 s under 1-sun irradiation. This outstanding performance is attributed to the synergistic effect of BCN and PEG2000, which enhances both thermal conduction and solar-thermal conversion. Overall, this study provides a sustainable approach for solar-assisted thermal management in energy-efficient non-structural buildings.