Final answer:
Lead-acid batteries use an aqueous sulfuric acid solution, while NiCad batteries use solids or pastes for electrolytes, maximizing surface area and efficiency.
Step-by-step explanation:
The major difference between the construction of the lead-acid and nickel-cadmium (NiCad) battery, other than the type of cell used, lies in the electrolyte and the physical structure. Lead-acid batteries utilize an aquatic solution of sulfuric acid as the electrolyte and have plates or grids of lead and lead dioxide as the anode and cathode respectively.
Meanwhile, NiCad batteries contain a cadmium anode and a highly oxidized nickel cathode, with the electrolyte often being a solid or paste to maximize surface area and electrical output per unit mass.