Towards safer lithium-ion battery modules enabled by dual-functionality of silica gel-based phase change materials

Ensuring thermal safety of lithium-ion batteries (LIBs) in practical applications relies on efficient thermal management and suppression of thermal runaway propagation (TRP). Herein, we report the rational design of two thermally enhanced phase change material (PCM)/silica composites (PSG 70 BN and PSG 70 SiC) are developed to address these challenges across multiple scales. At the materials level, their thermal conductivity was enhanced by 266 % (PSG 70 BN) and 241 % (PSG 70 SiC), respectively. To validate applicability at the cell level, the composites are applied to single LIBs under 2C discharge conditions, demonstrating up to a 15 % reduction in peak temperature and a noticeable decrease in inter-cell temperature gradients. Scaling up to the module level, TRP tests confirmed the materials' capacity to delay or suppress propagation: PSG 70 SiC extended thermal runaway onset to 650 s, while PSG 70 BN, with its thermal conductivity and heat shielding capability, effectively inhibited TRP across adjacent cells. Overall, PSG 70 BN exhibits dual-functional performance, highlighting the synergy between thermal conduction and insulation in passive battery safety strategies. These results offer a scalable pathway for advanced thermal management in next-generation energy storage systems. • Innovative solutions for the thermal safety of lithium-ion batteries are proposed. • PCM/SG has enhancement in thermal properties and improved thermal management. • Synergy of heat conductivity and heat shield inhibits thermal runaway propagation. • The mechanisms and propagation paths in battery modules are analyzed.