Lead-Alum — Solid Crystal rechargeable battery
This shows a homemade rechargeable Lead-Alum battery that has a solid Alum crystal formed between the anode and cathode plates. There is no seperator between the plates–only the crystal. Powdered Alum was heated to a liquid state and then poured into a tin foil mold that held the two pre-formed lead plates. The two lead plates were pre-formed in a solution of Alum and water. A charge of 6 volts was applied to the submerged plates to form the oxides. The plates were then air dried before the solid crystal cell was made. The cooled crystal cell had to be dipped in the Alum water solution to get enough hydration for the cell to take a charge.