The Polymer Society of Korea

Abstract

To leverage the advantages of lithium metal batteries, separator properties such as wettability and thermal stability are critical. Here, a porous separator was fabricated via a simple polymerization-induced phase separation (PIPS) method. The PIPS separator showed improved cycling stability over commercial PE, maintaining performance under 2C cycling at 3.0–4.3 V in Li/NCM811 cells and 0.5 mA cm⁻², 0.5 mAh cm⁻² in symmetric Li/Li cells. This was attributed to enhanced electrolyte uptake and wettability. It also mitigated capacity fading under 1C cycling at 60 °C, demonstrating thermal durability. Structural and compositional analyses—including SEM, CLSM, XPS, TOF-SIMS, and BET—were conducted with electrochemical tests. These results demonstrate that the PIPS-based separator offers a simple, scalable, and effective approach to improving the safety and performance of lithium metal batteries.