A high thermostability separator inhibiting the growing of Li dendrites for interfacially stable lithium-ion...

The thermal instability, limited wettability, and poor suppression capability of commercial polyolefin separators toward lithium dendrites can easily bring about battery short circuits and thermal runaway, resulting in severe safety issues. To address these challenges, we propose an advanced, dendrite-resistant, high-safety composite separator, ANF@MMT, which integrates ANF nanofibers and MMT clay nanoparticles. This design improves the pore structure of the pure ANF membrane while maintaining its excellent thermal stability, facilitating efficient Li⁺ delivery within the separator. Additionally, the incorporation of MMT inorganic components effectively suppresses lithium dendrite growth during cycling. The ANF@50MMT separator exhibits outstanding cyclic stability, the capacity retention rate of the LFP//Li half-cell is still as high as 95.2 % after 300 cycles, significantly outperforming the commercial Celgard2325 separator (87.04 %). Furthermore, the pouch battery assembled with the ANF@50MMT separator demonstrates a delayed ignition time of 68 s compared to the commercial separator, highlighting its enhanced safety performance.