Robust, High‐Temperature‐Resistant Aramid Nanofiber Separator with Hierarchical Structure for High‐Performance Lithium‐Ion Batteries (Small 37/2025)

Lithium-Ion Batteries In article number 2505087, Si-Cheng Li, Tao Ma, Kunyan Sui, and co-workers tackle thermal runaway in lithium-ion batteries with an aramid nanofiber (ANF) separator, synthesized via low-temperature polycondensation. The hierarchical lamellar ANF separator exhibits high mechanical strength and zero shrinkage at 300 °C, effectively preventing short circuits while maintaining stable high-temperature cycling with 94.6% capacity retention at 100 °C. This breakthrough design provides a fail-safe solution for next-generation, high-energy-density batteries.