Hierarchically channel-guided porous wood-derived shape-stabilized thermal regulated materials with enhanced thermal conductivity for thermal energy storage

Abstract

Low-cost, high thermal conductivity, shape-stable composite phase change materials (c-PCMs) are in high demand for energy saving, storage, and conversion. Novel carbonized wood/polyethylene glycol (PEG) c-PCMs were designed and prepared via a carbonization and vacuum impregnation process, using low-cost carbonized wood (c-wood) as the matrix material and PEG as the phase change material (PCM). c-Wood possessed a channel and porous structure with a high specific area of 230 m2 g−1. PEG was equally distributed in the matrix material with a mass fraction of approximately 67%. c-PCMs showed excellent compression strength with 18.7 MPa, which was 4.3 times greater than c-wood; and desirable thermal energy storage performance without any observable chemical interaction between c-wood and PEG. The prominent thermal conductivity of c-PCMs was 0.51 W m−1 · K−1, which was approximately three higher than pristine PEG. The morphology of c-PCM maintained its shape-stability during and after heat treatment at 80 °C for 40 h, and an outstanding thermal reliability was confirmed after 200 thermal cycles. Therefore, c-wood/PEG c-PCMs demonstrated promising potential as high-efficiency thermal energy storage materials for application in the energy saving sector.