(-) lead | sulfuric acid | lead oxide (+)
The anode active material is PbO2, the cathode material is sponge metal lead, and the electrolyte is dilute sulfuric acid.
Negative reaction: Pb+hso4 (-)-2e = = pbso4+h (+)
Positive reaction: PBO 2+3h (+)+hso4 (-)+2e = = pbso4 = 2h2o.
Battery reaction: Pb+PBO 2+2h (+)+2hso4 (-) = = 2pbsso4+2h2o.