Hydrogen‐Bond Enabled Phosphite Based Intrinsic Flame‐Retardant Solid‐Solid Phase Change Materials Using Catalyst/Solvent‐Free Multi‐Component Reaction for Battery Thermal Management

ABSTRACT

Leakage and flammability are two critical safety issues limiting the practical application of organic phase change materials. Herein, a facile catalyst/solvent‐free multicomponent reaction involving alcohols/amines/thiols, dimethyl phosphite, and benzaldehyde was developed to simultaneously address these drawbacks. The terminal phosphite groups endow intrinsic flame retardancy, while intermolecular interactions enhanced by P═O bonds transform the material into a viscous‐to‐solid state above its melting point, eliminating leakage. Notably, the reaction proceeds smoothly with quantitative yield under fully catalyst‐free conditions as nucleophilicity increases from alcohols to thiols. Battery thermal management tests show the intrinsic flame‐retardant solid‐solid phase change materials extend the safe operation of lithium‐ion batteries by 140%. Cone calorimeter tests reveal a 14 s ignition delay, and 37.6%, 29.8%, and 27.3% reductions in average heat release rate, total heat release, and total oxygen consumption compared to raw materials, confirming excellent flame retardancy. The material exhibits a maximum latent heat of 133.87 J/g, ensuring favorable thermal energy storage performance.