Patent ID: 7170739

Claim:
An electrochemical double layer capacitor having a separator comprising a porous layer of polymeric nanofibers having mean diameters in the range from about 50 nm to about 1000 nm, wherein the porous nanofiber layer has a mean flow pore size of between about 0.01 μm and about 10 μm, a thickness of between about 0.1 mils (0.0025 mm) and about 5 mils (0.127 mm), a basis weight of between about 1 g/m 2 and about 30 g/m 2 , a porosity of between about 20% and about 90%, a Frazier air permeability of less than about 80 cfm/ft 2 (24 m 3 /min/m 2 ) and a MacMullin number of between about 2 and about 15.