Delignified wood/polyethylene glycol-based material with BN as thermal conductive filler for thermal energy storage

Abstract

In this work, phase change energy storage wood (KBN-PCES@Balsa) was obtained by injecting PGMA into the porous tissue of wood by high temperature and high pressure method, and the BN grafted with KH550 and DA (KH550-DA-BN) was synthesized to improve the heat transfer rate. Studies have found that PGMA has good thermal conductivity in the cavities of woody cells. After adding KH550-DA-BN to PGMA, the KH550-DA-BN combines with PGMA in a physically dispersed manner and the crystal structure of PGMA does not change. When the filling amount of KH550-DA-BN is 6 wt%, the thermal conductivity of KBN-PCES@Balsa increases to 0.4185 W/(m·K), its melting enthalpy and solidification enthalpy are all maintained at 103.40 J/g and 100.20 J/g, respectively. The KBN-PCES@Balsa shows efficient solar-to-thermal energy conversion and a lasting heat storage capacity under simulated sunlight. After 200 cycles of cooling and heating, the melting enthalpy and solidification enthalpy of KBN-PCES@Balsa are both above 120 J/g, indicating that KBN-PCES@Balsa has good stability in use. There is no leakage of 6 % KBN-PCES@Balsa after heated at 80 °C for 4 h, due to the interpenetrating network structure between PGMA and wood components. The phase change heat storage wood prepared in this research increases the potential of wood for temperature regulation in fields such as building materials, furniture and aerospace.