Covalent halogenation of polyethylene glycol-based flame-retardant phase change materials for safe energy storage

To address the synergistic challenge of regulating phase change properties and optimizing flame-retardant performance in phase change materials (PCMs), this study uses a brominated molecular engineering approach to concurrently regulate phase change properties and enhance flame-retardant performance in PCMs. By covalently modifying hydroxyl sites with bromine, the strategy achieves dual functionality: bromine acts as both a hydrogen-bond modulator to tailor phase change temperatures (expanding the range by 10.72%) and latent heat, and an intrinsic flame-retardant unit that reduces peak CO₂ yield by 39.55%, maximum effective heat of combustion by 19.85%, and average heat release rate by 9.17%. The material also exhibits flexibility and self-healing capabilities. This molecular-level atomic substitution strategy provides a unified chemical framework for balancing these properties, offering promise for applications in battery thermal management and building insulation, and laying the groundwork for next-generation multifunctional PCMs.