The disclosure relates to the manufacturing of a lead-acid battery that includes a composite that includes lead oxide and a nanomaterial. A method of preparing the composite is disclosed. In one embodiment, an in-situ sol-gel reaction of a solution occurs in the presence of lead oxide to produce a composite that includes the lead oxide and a nanomaterial (e.g., a nano-oxide). The solution may include a precursor that includes metal alkoxide or silicate. The composite may include the lead oxide and the nanomaterial dispersed or distributed among particles of the lead oxide. A lead-acid battery may be manufactured using the composite. Various properties of a lead-acid battery may be improved by using the composite as part of the active material including a longer life expectancy, increased specific energy and increased power-to-weight ratio.