A heat resistant and flame-retardant polysulfonamide/polypropylene composite nonwoven has been developed and exploited as an advanced separator for high performance lithium ion battery via melt-blown spinning followed by a phase-inversion process. It was manifested that such composite nonwoven exhibited improved flame retardance, superior thermal resistance and better electrolyte wettability as compared to commercialized polypropylene separator. It was also demonstrated that the lithium cobalt oxide (LiCoO2)/graphite cells employing the composite separator possessed better rate capability and superior cycling stability than those of polypropylene separator. Furthermore, this study verified the beneficial impact of polysulfonamide/polypropylene composite separator with respect to commercial polypropylene separator on cycle performance of lithium iron phosphate (LiFePO4)/lithium (Li) cells even at an elevated temperature of 120 degrees C. These fascinating results suggest that such composite nonwoven is promising separator for high performance lithium ion battery. (C) 2014 The Electrochemical Society. All rights reserved.