Cellulose-ceramic composite flexible paper separator with improved wettability and flame retardant properties for lithium-ion batteries

Abstract

In quest of developing sustainable separator for lithium-ion batteries (LIBs), this research focuses on functionalization of low cost cellulose based commercial paper using duo-polymer and nano-SiO₂ by designing a facile aqueous based industry friendly wet-coating process. Unlike commercial plastic based polyolefin separators (polypropylene/polyethylene), the developed paper separator shows superior thermal stability > 200 °C without dimensional shrinkage, excellent electrolyte wettability (147%) with zero contact angle, quicker electrolyte saturation and satisfactory mechanical strength (34.86–38.31 MPa). The electrochemical performance carried out in 2032 coin cells using fabricated paper separators shows comparable performance to that of commercial polypropylene (PP) based separator at different current densities of 0.05–0.4 mA/cm² with excellent columbic efficiency (> 96%) and good capacity retention on cycling. The developed separator is found to be compatible with most of the commercial electrodes (MCMB, LiCoO₂, LiFePO₄) used in today’s LIBs. The functionalized cellulose-ceramic composite paper separator shows excellent flame retardant properties by offering an added safety features for its successful use in lithium-ion batteries.