A flexible high-temperature insulating high entropy ceramic fiber membrane for thermal runaway protection in lithium-ion batteries

Abstract

High-temperature-resistant ceramic fibers are critical materials in emerging applications, including thermal protection for spacecraft, heat exchange systems in petroleum pipelines, thermal insulation in construction, and thermal runaway protection in lithium-ion batteries. However, the brittle failure of oxidized ceramic fibers often leads to structural degradation, limiting their long-term performance at high temperatures. In this study, we present the design of a flexible and durable high-entropy lanthanum zirconate-based silica composite nanofiber membrane, specifically developed for high-temperature thermal protection in lithium-ion batteries. The resultant (La_0.2Ce_0.2Gd_0.2Er_0.2Sm_0.2)₂Zr₂O₇–SiO₂ membrane exhibits an ultra-low thermal conductivity of 0.036 W m⁻¹ K⁻¹ at room temperature and retains good flexibility under 1200 °C. This ceramic membrane also demonstrates exceptional high-temperature insulation performance, with a cold surface temperature of only 332 °C when the hot surface is maintained at 1200 °C, at a thickness of 10 mm. Additionally, the high-entropy ceramic membrane is shown to effectively prevent heat propagation thus secondary explosions in lithium-ion batteries during thermal runaway. This work provides new insight into the rational design of advanced thermal runaway protection for lithium-ion batteries under high temperatures.