The variation of discharge
capacity during charge-discharge cycling of a PbO2 electrode,
prepared by pressing PbO2 powder onto a smooth lead disc, in
sulfuric acid and acidic ammonium sulfate solutions of various concentrations
was investigated by the potentiodynamic technique. The discharge capacity was
found to increase with cycle number in 0.05-4.3 H2SO4; this was
explained in terms of the increase in porosity of the electrode with cycling.
The rate of increase was highest in a 1 mol dm-3 solution. The presence
of ammonium sulfate decreased the discharge capacity at all concentrations of sulfuric
acid except for the 1 mol dm-3
solution where it caused a small increase in capacity. The morphology of the
electrode was studied by scanning electron microscopy and the results are
correlated with the discharge capacity. These results indicated that a solution
of composition 0.5 mol dm-3 ammonium sulfate and 1.0 mol dm-3
sulfuric acid will produce a greater utilization of positive plate active material
(PbO2) during discharge. This result, taken together with the
results of earlier studies on lead in acidic sulfate electrolytes, points to
the possibility of a Pb/H2SO4,/PbO2 battery
for electric-vehicle propulsion.
Oriented Crystallization of Ammonium Sulfate from Hexagonal Boron Nitride/Sulfuric Acid Intercalation Compounds