Intrinsic flame-retarded phase change material based on molecular modification of 1-hexadecanol for battery thermal management

Organic phase change materials (PCMs) are highly flammable, presenting substantial safety risks in battery thermal management (BTM) applications. In this study, based on the nucleophilic addition reaction, a novel flame-retarded PCM is synthesized via a reaction between 3-isocyanatopropyltrimethoxysilane and 1-hexadecanol (HD). The latent heat of the obtained silyl-modified HD (SiHD) is up to 115.1 J·g −1 , and its peak phase transition temperature region is approximately 30–45 °C. Moreover, the silyl groups endow the SiHD with significantly enhanced flame-retarded properties. After incorporating expanded graphite (EG) as both supporting and thermal conductive frameworks, the SiHD/EG composite PCM possesses a thermal conductivity of 1.85 W·m −1 ·K −1 and an excellent anti-leakage performance. During the BTM tests, the maximum temperature difference of the battery module with SiHD/EG is reduced by approximately 23 %, and the maximum temperature is decreased by about 3 °C in comparison to those with traditional flame-retarded PCMs. Additionally, in extreme overheating conditions, the resultant SiHD/EG can effectively delay thermal propagation, thereby postponing the occurrence of thermal runaway.