Thermal-responsive, super-strong, ultrathin firewalls for quenching thermal runaway in high-energy battery modules

Cascaded thermal runaway (TR) propagation is the utmost safety issue for large-format lithium-ion battery (LIB) modules because of the high risk of system fires or explosions. However, quenching TR without side effects still remains a challenge. Herein, we delivered an ultrathin smart firewall concept for avoiding the TR propagation in a LIB module. We demonstrate that the firewalls have thermally-triggered switchable thermal physical properties because of the synergistic effect of non-flammable phase change materials (NFPCM) and flexible silica nanofiber mats. Under TR condition, the firewalls give rise to multiple functions simultaneously, including cooling, fire extinguishing and thermal insulation. Consequently, the TR propagation between fully charged 50 Ah LIBs, with a transient thermal shock of up to 53 kW, is successfully suppressed by 1-mm-thick smart firewalls, yielding a maximum cell-to-cell temperature gap of 512 °C. The smart firewall design provides a reliable approach to quench TR propagation in large-format LIBs, which can also be suitable for other dynamically adaptive thermal-protection applications for oil tanks, space exploration, and firefighting equipment.