Leady oxide (LO) containing different amounts of mineral additive(0-15 wt. % (w/o)) was mixed with water and 1.40 s.g. H2SO4 in a ratio equal to 5% H2SO4/LO). The mixtures were homogenized during 30 min and cured 3BS pastes were obtained. The formation of the mixture was achieved by the employment of a tubular electrode. Before each experiment, the PbeSb spine was previously polarized at 1.3 V/Hg/Hg2SO4/saturated K2SO4 in 1.28 s.g. H2SO4 solution so that a conductive anodic layer of PbO2 is obtained. This layer ensures the contact between the spine and 3BS and initiates its conversion to PbO2. Each electrode is filled with 3BS powder. All electrodes are formed in 1.05 s.g H2SO4 solution. The electrodes were polarized at a constant current of 50 mA until the complete mass of 3BS is totally converted to a brownish-black PbO2 powder The samples were washed with a hot saturated ammonium acetate solution to remove PbSO4, then washed with distilled water and overnight dried at 60 C.