Patent ID: 8900758

Claim:
A process for preparing a separator for an electrochemical device, comprising the steps of: applying a slurry including at least cellulose fibers and a hydrophilic pore former with a boiling point of 180° C. or more onto a substrate; drying said slurry to form a sheet on said substrate; and separating said sheet from said substrate to obtain a separator, wherein said separator has a volume resistivity of 1,500 Ω·cm or less determined by alternate current with a frequency of 20 kHz in which said separator is impregnated with a 1 mol/LiPF 6 /propylene carbonate solution, and wherein said cellulose fibers contain fibers having a diameter of 1 μm or more in an amount of 5% by weight or more on the basis of the total weight of said cellulose fibers.