HIGH TENSILE STRENGTH PAPER SUITABLE FOR USE IN ELECTROCHEMICAL CELLS
A paper suitable for use as a separator paper in electrochemical cells and an electrochemical cell comprising same, the paper comprising as the sole fibrous components (95) to (100) weight percent fibrils and (0) to (5) weight percent aramid fibrids and having a thickness of (10) to (40) micrometers and a tensile strength of at least (15) megapascals or greater, the fibrils comprising a polymer blend of (80) to (96) weight percent polyparaphenylene terephthalamide and (4) to (20) weight percent of polyvinylpyrrolidone; the fibrils having a diameter of (10) to (2000) nanometers, a length of (0.2) to (3) millimeters, a surface area of (3) to (40) square meters/gram, and a Canadian Standard Freeness of (0) to (10) milliliters.