Fire-resistant polyimide-silica composite aerogels with high thermal insulation and flame retardance towards preventing thermal runaway propagation of lithium-ion batteries

Abstract

Thermal runaway propagation (TRP) remains a critical safety challenge in lithium-ion battery systems. Incorporating barrier materials between adjacent cells is a widely adopted and effective strategy to mitigate TRP. This study introduces a novel PI/SiO2 composite barrier material composed of polyimide aerogel (PI), hydroxyapatite nanowires (HAP), ammonium polyphosphate (APP), silica gel, and PR-MoS2/EP, designed to effectively suppress TRP. Experimental results reveal the progressively improved TRP suppression performance with the increasing thickness of barrier material. Notably, PI@SiO2/EP-3 composite fully inhibits TRP between batteries, leading to the relatively-low peak temperature (∼137 ℃) and stable voltage (∼4.136 V). Additionally, the total enthalpy exchange between two cells during TRP is decreased by 51.8 %, from 56.4 to 27.2 kJ, yielding the lowest total heat release of 0.29 MJ/m2. The survived cell exhibits the minimal changes in internal crystal structure and chemical composition. This work underscores the importance of aerogel-based barrier material in disrupting TRP pathways and presents a promising strategy for enhancing battery safety in electric vehicles, grid-scale storage, and other high-risk energy applications.