A battery separator comprising an ultra-high molecular weight polyethylene microporous membrane radiation grafted with a monomer, the separator having the following properties: (a) a porosity ranging from about 50% to about 95%, (b) an average pore size ranging from about 0.1 to about 20 microns, (c) an electrolytic resistance ranging from about 1 to about 50 m OMEGA -in2, (d) a maximum weight loss of 1% and a change in electrolytic resistance of no greater than 25% after immersion in an aqueous solution of 35% KOH and 5% KMnO4 at 50 DEG C. for 1 hour, (e) a tensile strength of from about 3.5 to about 5.5 lb/in in both length and width directions, (f) a KOH absorption ratio of from about 5 to about 30, (g) a Gurley air permeability of about 1 to 300 sec/10 ml, and (h) a thickness from about 0.5 mil to about 10 mil. Further provided is a battery comprising at least one pair of electrodes of opposite polarity, an electrolyte, and a separator of the present invention located between the electrodes of opposite polarity.
展开▼
