Orderly hybrid aerogel-based hydrate salt for wide-temperature range thermal regulation and flame retardancy in Li-ion batteries

Abstract

Due to the rapid expansion of electric vehicles, the performance and safety of Li-ion batteries under extreme conditions must be urgently improved. Herein, an ordered, porous and hybrid boron nitride/melamine formaldehyde/polyvinyl alcohol (BN/MF/PVA) aerogel was designed as a skeleton for sodium acetate trihydrate (SAT) to fabricate a hydrate salt composite. Benefiting from the structure design, the composite exhibits large latent heat and superior shape-stability, thermal conductivity and mechanical performance. The outstanding comprehensive thermal properties, integrating phase change from −30 °C to 60 °C, enable the composite to efficiently regulate temperature across a wide range. Surprisingly, the heat release from the composite-warmed battery pack in a −30 °C environment increased by 9.6 °C and the discharge capacity improved by 25.6%. Furthermore, cooling from the SAT thermochemical reaction, combined with air isolation via MF thermal decomposition, reduced the heat release (14.7 kJ g⁻¹) and enhanced the tolerated temperature (511 °C), allowing the flame to endure for up to 30 seconds and extinguish it in 5 seconds with a few amount of coke. Owing to its competitive flame-retardant capacity and highly efficient wide-range thermal regulation, the aerogel-based hydrate salt composite shows potential for enhancing battery performance and safety.