The Polymer Society of Korea

Abstract

Conventional polyolefin separators hinder high-rate lithium metal batteries (LMBs) due to poor wettability and thermal instability, which induce polarization and dendritic growth. Here, we report a polymeric nanofiber separator that overcomes these limitations via synergistic structural and chemical design. The porous architecture ensures rapid electrolyte uptake and continuous ion pathways. Crucially, spectroscopic analyses reveal that polar functional groups in the polymer backbone coordinate with Li⁺ to facilitate transport while immobilizing anions, thereby increasing the lithium transference number. This dual mechanism promotes uniform Li deposition and suppresses dendrite formation, while the thermally robust framework prevents thermal shrinkage. Consequently, the separator enables stable cycling at 1C for over 500 cycles with 94% capacity retention, demonstrating a promising strategy for safe and reliable high-rate LMBs.