A method for producing a lead acid battery that operates on the oxygen cycle is disclosed. The method includes the steps of: assembling a cell comprising a positive plate, a negative plate, and a sheet of separator material which is an absorbent, porous filtration medium, so that there is free space between the plates and surfaces of the separator, inserting the cell into a case, introducing into the case a mixture of sulfuric acid and silica including silica from a never dried precipitated silica slurry, causing the sulfuric acid in the mixture in the free space to gel, and sealing the case. The sulfuric acid in the mixture in the free space can be caused to gel by an increase in the silica content thereof, by an increase in the specific gravity thereof, or by both an increase in the silica content thereof, and an increase in the specific gravity thereof.