Separator for electrochemical device and process for preparing the same

摘要

The present invention relates to a process for preparing a separator for an electrochemical device, including 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 the slurry to form a sheet on the substrate; and separating the sheet from the substrate to obtain a separator, wherein the separator has a volume resistivity of 1500 Ω·cm or less determined by alternate current with a frequency of 20 kHz in which the separator is impregnated with a 1 mol/LiPF6/propylene carbonate solution. The present invention can provide a separator for electrochemical devices which has superior separator properties such as low inner resistivity for electrochemical devices, has high lithium shielding properties that cannot be exerted by non-woven fabrics, paper or the like, and can be prepared at a reasonable cost.

主权项

1. 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/LiPF6/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.