A core-shell structured polysulfonamide@polyvinylidene fluoride-co-hexafluoropropene composite nonwoven separator was exploited for lithium ion battery via coaxial electrospinning technique for enhanced safety characteristic of battery. Polysulfonamide (PSA) and polyvinylidene fluoride-co-hexafluoropropene (PVDF-HFP) were used as the inner (core) and outer (shell) layer, respectively. Compared with the commercial polypropylene (PP) separator, the PSA@PVDF-HFP composite nonwoven separator manifested higher porosity, better electrolyte wettability and superior thermal stability. Moreover, it was demonstrated that the assembled cell with PSA@PVDF-HFP composite nonwoven separator displayed superior rate capability and better cycling capacity retention than those of PP separator. Notably, these attractive characteristics would endow PSA@PVDF-HFP composite nonwoven a promising separator for high power lithium ion battery. (C) 2013 The Electrochemical Society.