“…Concentration of sulfuric acid and fumed silica are the key parameters to affect the performance and capacity of VRLA batteries [15,19,20]. The optimum amount of sulfuric acid and fumed silica those were determined in our previous study as 30 wt% and 6 wt%, respectively, were used in this study [15]. In order to investigate the effect of inorganic additives, Al2O3 (Sigma-Aldrich, ≥ 98%, St. Louis, USA), B2O3 (Sigma-Aldrich, ≥ 99%, St. Louis, USA) and TiO2 (Sigma-Aldrich, ≥ 99%, St. Louis, USA) were added into the electrolyte.…”