Boron nitride based nanostructure inspired flame retarded thermoplastic polyurethane composites: Comprehensive evaluation and mechanism investigation

Thermal runaway propagation (TRP) between batteries tends to induce the derivatives disasters of whole system, including fire or explosion, which inevitably causes vast economic losses and human casualties. In this work, the thermoplastic polyurethane (TPU) composites with flame retardants are fabricated as barrier plate to inhibit the TRP of batteries. Here, hexagonal boron nitride (h-BN) nanosheets are utilized as platform to assemble layered double hydroxides (LDHs) nanoflakes, to acquire the flame-retardant fillers (CBN-LDH-1, CBN-LDH-2, CBN-LDH-3). By using 6.0 wt% CBN-LDH-3, the peak heat release rate (PHHR), total heat release (THR), peak smoke production rate (PSPR) and total smoke production (TSP) of TPU are decreased by 48.4 %, 44.8 %, 46.5 % and 51.5 %, respectively. Meanwhile, the total CO₂ production (TCO₂P) is reduced by 45.2 %. These results reflect the markedly improved flame retardancy. Further assessment also verifies the superior merit of CBN-LDH-3 in reducing the fire hazard of TPU. By using TPU/6.0 CBN-LDH-3 as barrier plate, the TRP of batteries is inhibited at some degree. In specific, the time interval is increased from 104 s to 163 s. This work can provide inspirations for the design of TRP suppression materials, guaranteeing the safety of battery.