Effect of fumed silica particle sizes and polymer additives on gelled electrolyte in valve-regulated lead-acid battery

This research studied the effects of fumed silica particle sizes and additives on gelled electrolyte in valve regulated lead-acid battery by measuring the discharge capacity of battery, conductivity values and the hydrogen-oxygen evolution of gelled electrolytes. The gelled electrolytes consist of 2-5% (w/v) of fumed silica, 1.280 specific gravity of sulfuric acid and 0.005, 0.01, 0.02% (w/v) of additives. The results showed that increasing fumed silica content provided the better gelation likewise some additives. In addition, the fumed silica particle sizes, fumed silica content, types of additive and concentration of additive resulted in higher discharge capacity and conductivity. For the hydrogen-oxygen evolution study it was shown that fumed silica particle size 12 nanometers decreased the hydrogen-oxygen evolution better than fumed silica particle size 7 nanometers. Some additives and their concentration were inefficient on the hydrogen-oxygen evolution. The effect of hydrogen-oxygen evolution could influence the cycle life of VRLA battery. For the gelled electrolyte with 0.01 (w/v) of polypyrrole, 4% (w/v) of fumed silica content and 1.280 specific gravity of H₂SO₄ provided the highest discharge capacity of 2.5 Ah. This capacity was higher than the standard VRLA battery. The gelled electrolyte with 0.01% (w/v) of dye, 3% (w/v) of fumed silica content and 1.280 specific gravity of H₂SO₄ offers the highest conductivity values of 836 mS/cm. The decreasing of hydrogen-oxygen evolution was improved by gelled electrolyte with ionic liquid. From XRD analysis, it was found that adding the additives in gelled electrolyte showed no effect on the reaction on negative plate electrode of VRLA battery.