The performance of lithium ion battery based on electrospun nanofibrous membranes has gained a
great deal of attention in the past decades, but the intrinsic low mechanical strength and large pore size
of electrospun membranes limit their battery performance. To overcome this limitation, a powerful
strategy for designing, fabricating and evaluating silica nanoparticles coated polyetherimidepolyurethane (SiO2/PEI-PU) nanofibrous composite membranes is easily developed via electrospinning
followed by a dip-coating process. Benefiting from the high porosity, interpenetrating network
structure and synergetic effect of PU, PEI and SiO2 nanoparticles, the as-prepared composite
membranes exhibit high ionic conductivity (2.33 mS cm1
), robust tensile strength (15.65 MPa) and
improved safety (excellent thermal resistance and flame retardant property). Additionally, the asprepared composite membranes possess relatively narrow pore size distribution with average pore size
of 0.58mm after coating SiO2nanoparticles, which plays an important role in hindering the microshorting and mitigating self-discharge. Significantly, the SiO2/PEI-PU membranes based Li/LiFePO4cell
exhibits more excellent cycling stability with capacity retention of 98.7% after 50 cycles at 0.2 C rate and
better rate capability compared with the Celgard membrane based cell. The results clearly demonstrate
that this is a promising separator candidate for next-generation lithium ion batteries, which may
represent a significant step toward separators with improved performance