POS6-1396
Synthesis and Characterization of Shutdown-Enabled and Flame Retardant Polyethylene Lithium-Ion Battery Separator using Phosphorus-Rich Poly (vinyl acetate-acrylonitrile) Microparticles
When and Where
Nov 30, -0001
00:00 - 00:00
Room 301 (Grand Ballroom)
Presenter(s)
Kyoung-Jin Choi (Korea Research Institute of Chemical Technology (KRICT), Kyonggi University)
Co-Author(s)
Abstract
Lithium-ion batteries (LIBs) are widely used in various fields such as electric vehicles and energy storage systems due to their high energy density and lightweight characteristics. However, safety issues have also become increasingly critical. Currently, commercial separators mainly used are polyethylene (PE) and/or polypropylene (PP) because of their low cost. Herein, we synthesize the poly(vinyl acetate-acrylonitrile) particles with a phosphorus-rich shell via an environmentally benign aqueous process. The particles were subsequently coated onto PE separators through a water-based roll-to-roll coating process, thereby introducing a thermally responsive shutdown function. The chemical structure of the phosphorus-rich particles was confirmed via FT-IR and 1H NMR spectroscopy, while their morphology, particle size, and phosphorus-rich core-shell architecture were characterized using SEM and TEM-EDS. The coated PE separator exhibited a remarkably low thermal shrinkage of 12.5% after heat treatment at 140 oC for 60 min, compared with 81.5% shrinkage for the bare PE separator under the same conditions. Also, thermal shutdown behavior was further investigated by electrochemical impedance spectroscopy (EIS) at 130 oC using an EMIM-TFSI-based electrolyte to minimize electrolyte evaporation during high temperature measurements. The coated PE separator exhibited a significantly higher resistance (26.1 Ω) than the pristine PE separator (7.8 Ω), indicating effective suppression of ion transport at elevated temperatures. In addition to its shutdown functionality, the phosphorus-rich shell imparted flame retardant characteristics to the coated PE separator. In the UL-94 test, the bare PE separator immediately burned to the top of the specimen, indicating that no UL-94 rating was achieved. In contrast, the coated PE separator did not sustain combustion after either the first or second ignition with no cotton ignition, thereby achieving VTM-0 rating.
