Self-triggered fire-extinguishing microcapsules with pronounced performance in suppressing the thermal runaway of lithium-ion batteries

Abstract

Lithium-ion batteries are prone to thermal runaway under various abuse conditions, which may result in fires or explosions. Common fire-extinguishing agents face several challenges when applied to lithium-ion battery fires. These include long durations for extinguishing, risks of external short circuits, and inability to effectively block heat propagation. Additionally, these agents exhibit a delay from the time the detector detects a fire to the release of the extinguishing agent, which prevents them from quickly locating and extinguishing the fire. Therefore, it is necessary to develop a no-delay and highly efficient fire extinguishing technology to address lithium-ion battery thermal runaway. In response to the unique characteristics of lithium-ion battery fires, a novel temperature self-triggered microcapsule fire extinguishing agent (MC@NH) with perfluorohexanone (Novec 1230) and cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)) as the core material and melamine–urea–formaldehyde resin as the shell material was prepared by the in situ polymerization method, possessing dual effects of extinguishing and cooling. The extinguishing and cooling effects of microcapsule fire extinguishing agents were verified, as well as their ability to inhibit thermal runaway in lithium-ion batteries. The results indicate that microcapsule fire extinguishing agents exhibit good thermal responsiveness and strong heat absorption capacity. Microcapsule fire extinguishing agents rupture at 130 °C, releasing Novec 1230 and HFO-1336mzz(Z). Novec 1230 can extinguish the flames formed by combustible materials released from lithium-ion batteries, while HFO-1336mzz(Z) can provide efficient cooling effects. The combined action of the two enables a limited amount of microcapsule fire extinguishing agent to delay the thermal runaway of lithium-ion batteries and effectively inhibit the propagation of thermal runaway. The novel temperature self-triggered microcapsule fire extinguishing agent has provided a new strategy for the inhibition of thermal runaway in lithium-ion batteries.