| 摘要 |
PROBLEM TO BE SOLVED: To provide a separator for an electrochemical device which is small and even in bore diameters, and has a high strength and no pin hole produced therein even when arranged in the form of a thin film.SOLUTION: The separator for an electrochemical device comprises, as a primary component, (A) cellulose fibers having a number average fiber diameter of 2-500 nm, in which the cellulose has a cellulose I-type crystal structure, a hydroxyl group at the C6 position of each glucose unit in a cellulose molecule is changed to any one of an aldehyde group, ketone group and carboxyl group through selective oxidation modification, and the content of the carboxyl group is in a range of 0.6-2.5 mmol/g. |
