Paper:method of making:battery separators

摘要

Cellulose fibres, having a diameter of 1 um or less, are formed into a wet web which is dried while retaining voids in the web to form a paper which is dense and airtight but has minute pores. The voids are retained during drying by replacing web moisture with a water-compatible solvent, by freeze-drying web moisture or by evaporating an organic solvent in the web. The cellulose fibres are formed by beating to a JIS-CSF value of at most 200 ml. The paper may form a separator in an electrolytic capacitor, or in a non-aqueous battery where it may reduce short-circuit failure and increase ion transmission. The paper may be used as a filter.