UV-cured gel polymer electrolytes based on poly (ethylene glycol) and organo-modified nanoclays for lithium ions batteries

Abstract

Next-generation electrolytes for Lithium Ion Batteries (LIBs) must provide increased durability, reliability, safety, and scalability to meet the even more stringent technical requirements of crucial industries such as e-mobility. A promising strategy to merge these technical needs is the development of easy-to-prepare gel polymer electrolytes (GPEs) able to ensure satisfactory conductivity, high stability, and reduced flammability. In this study, we propose the preparation of novel nanocomposite GPEs through one-pot in-situ photo-polymerization (UV-curing), which turns out to be of great interest due to its low-cost, solvent-free and energy-saving characteristics. Poly (ethylene glycol) dimethacrylate (PEG-DMA) was used as hosting polymer matrix, while 1 M Lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) in ethylene carbonate/dimethyl carbonate (EC/DMC) was used as electrolyte solution. Organo-modified montmorillonite (fMt, intercalated with CTAB) was synthesized and tested as a nanofiller. Both materials and GPEs were characterized by a combination of experimental techniques including FTIR, XRD, SEM, and DMA. Noteworthy, a thorough and systematic study of the lithium-ion transport properties in the prepared GPEs was carried out using pulsed-field gradient nuclear magnetic resonance (PFG-NMR) and electrochemical impedance spectroscopy (EIS). This preliminary study demonstrated the gP-fMt combines ease of preparation and excellent safety (i.e., thermomechanical stability up to 250 °C and nonflammability) with satisfactory lithium transport properties.