Flame retardant wood-based phase change materials with inorganic hydrated salt for thermal energy storage

Phase change materials show great promise for reducing energy consumption and relieving current energy shortage problems. Delignified wood (DW) with environmental friendliness as supporting frame can effectively mitigate leakage of phase change materials to ensure structural stability. However, conventional organic phase change/wood composites present a risk of flammability in application. Herein, we fabricate flame retardant wood-based phase change materials, in which disodium phosphate dodecahydrate (Na₂HPO₄·12H₂O) is used as inorganic phase change materials with nonflammable property. Meanwhile, sodium metasilicate hydrate (Na 2 SiO 3 ·9H 2 O) as a phase change material and nucleating agent is introduced in the wood-based phase change materials to reduce the supercooling of Na₂HPO₄·12H₂O. Na 2 SiO 3 ·9H 2 O/Na₂HPO₄·12H₂O/DW composites (NaSiO/NaHPO/DW) exhibit excellent flame retardant property (HRR<10 KW/m 2 ). In addition, flame retardant wood-based phase change materials possess high energy storage density (197.31 J/g) and high thermal conductivity, which show great potential in applications for advanced energy conversion management and prolonged high-temperature storage. • Wood-based phase change materials exhibit flame retardance and high heat enthalpy. • Na₂HPO₄·12H₂O acts as both phase change material and flame retardant. • Na 2 SiO 3 ·9H 2 O addresses the supercooling of Na₂HPO₄·12H₂O. • Wood-based phase change materials possess high thermal conductivity.