Aerogel-Based Phase Change Materials Meet Flame Retardancy: From Materials to Properties

Energy storage materials play a crucial role in enhancing system efficiency by bridging the mismatch between energy supply and demand. Among them, organic phase change materials (PCMs) are particularly attractive due to their high energy storage density, no phase segregation and ability to maintain nearly constant temperatures during phase transitions. However, their practical application is hindered by drawbacks such as leakage and flammability. Aerogels, characterized by high porosity, low density, and tunable structures, provide effective support matrices for encapsulating PCMs, thereby improving shape stability and enabling fire safety improvements when combined with flame-retardant strategies. Despite significant progress in PCM and aerogel research over the past decade, comprehensive studies dedicated to flame-retardant aerogel-based PCMs remain limited. This review systematically summarizes current flame-retardant approaches for aerogel-based PCMs, highlights recent advances in aerogel-supported systems, and outlines the key challenges and future opportunities for developing next-generation energy storage composites with improved thermal reliability, safety, and sustainability.