A method of preparing a hydrophilized separator material comprising:
carding a mixture of fibers having different softening ranges to form a nonwoven fabric, wherein said fibers are selected from the group consisting of polyamide and polyolefin fibers;
heating said nonwoven fabric to a temperature that is above the softening range of the lower-melting fibers;
compressing and bonding said non-woven fabric;
calibrating the compressed and bonded nonwoven fabric to form a layer of separator material;
spraying said layer of separator material with 0.5 to 7 weight percent, with respect to the dry weight of said separator material, of deionized water.