Disclosed is a battery separator, comprising two fiber regions comprising glass fibers, and a middle fiber region disposed between them comprising larger average diameter fibers and specified amounts of silica, or fine fibers, or both; and processes for making the separator. Also disclosed is a battery separator, comprising a fiber region and either one or two silica-containing region(s) adjacent thereto, each of the regions containing a specified amount of silica; and processes for making the separator. Such separators are useful, e.g., in lead-acid batteries.