Delignified wood for thermal energy storage with high efficient photo-thermal conversion efficiency

Abstract

Wood is widely used in human life as a natural renewable material. Improving the temperature regulation function of wood is of great significance to reduce the consumption of fossil energy and promote the construction of a low-carbon society. In this study, a phase change energy storage wood (PCES-Wood) with efficient photo-heat conversion efficiency was obtained by impregnating polyethylene glycol based composite material and graphene quantum dot grafted boron nitride (GQDs-BN) as thermal conductive filler. The results show that the thermal stability and the dispersion of GQDs-BN are improved. GQDs-BN shows strong light absorption in both UV and visible segments, and the thermal conductivity exhibited by PCES-Wood reaches 0.3916 W/(m·K) with the GQDs-BN content reaching 6 %. The phase transition temperature of PCES-Wood is between 20.29 °C and 36.29 °C, and the melting and solidification enthalpies reach 114.90 J/g and 113.70 J/g, respectively, reflecting a high latent heat value and a range suitable for human comfort temperature. 6 % GQ-BN-PCES @ Balsa also shows a low leakage rate as only 0.70 % at high temperature. After simulating sunlight exposure, the surface temperature of GQ-BN-PCES @ Balsa increases rapidly and the heat storage capacity is persistent under low-temperature conditions. The PCES-Wood prepared in this study enhances the potential of wood application in the field of temperature regulation.