New or improved battery separators for lead-acid batteries that include a carbon or mineral additive applied to the separator. In possibly preferred embodiments, the battery separator may include engineered carbon materials applied to the battery separator to modify sulfate crystal formation while decreasing the detrimental consequences of excessive gas evolution into the negative electrode itself. In one embodiment, a method of enhancing the lead-acid energy storage performance of a lead-acid battery may include delivering carbon to the negative active material surface of the battery separator where the carbon may effectively enhance charge acceptance and improve life cycle performance of a lead-acid battery.