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

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 degrees 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/cm(2) 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 lithiumion batteries.