A Novel Gel Electrolyte for Valve-Regulated Lead Acid Battery

Abstract

A novel gel electrolyte system used in lead-acid batteries was investigated in this work. The gel systems were prepared by addition of different amount of Al2O3, TiO2 and B2O3 into the gelled system consisting of 6 wt% fumed silica and 30 wt% sulfuric acid solution for the first time. The anodic peak currents and peak redox capacities of the gel electrolytes were characterized by cyclic voltammetric method. When B2O3 and Al2O3 were used as additives in fumed silica based gel electrolyte system, the anodic peak currents and peak redox capacities decreased. However, the investigated parameters in cyclic voltammetry (anodic peak current and capacities) increased by the adding of 3.0 wt% of TiO2 in the fumed silica based gel system. The solution and charge transfer resistances of the gel electrolytes were investigated by electrochemical impedance spectroscopy. While the solution resistances were lower in gel systems having different amount additives than pure fumed silica based gel, the charge transfer resistance was the lowest in gel electrolytes consisting fumed silica and fumed silica-TiO2. The morphological differences of gelled systems were elucidated by scanning electron microscopic and optic microscopic analysis. The battery performances were studied by obtaining discharge curves of prepared gel electrolytes. The performance of gelled systems were higher than that of non-gelled electrolyte at room temperature. The mixture of fumed silica-TiO2 was suggested an alternative gel formulation for gel valve-regulated lead acid batteries. TiO2 can be a useful additive for gel-VRLA batteries.

A novel electrolyte additive for gel type valve regulated lead acid batteries: Sulfur doped graphene oxide

“…28 The higher amount of additive in the gelled system caused the closing of porous sides of electrolyte. 28,32 This also decreased interactions of mobile ions and electrode surface. On the other side, in the gelled system consisting of lower amount of additive than that of 0.6 wt%, hydrolyzed particles of fumed silica were probably close to the porous side of the hybrid skeleton of gelled electrolyte.…”

“…13,21,42 Gelled electrolytes were prepared by using fumed silica (6 wt%) and sulfuric acid (30 wt%). 20,28,32,33 Different amount of S-GrOP (0.2, 0.4, 0.6, 0.8, and 1.0 wt%) was added into the fumed silica-based gelled system. Then, stirring time and stirring rate were optimized by electrochemical methods.…”

“…This also supported that the formed fumed silica-based gelled systems by addition of S-GrOP let to decrease the resistance of charge transfer for the formation of lead sulfate from metallic lead. 28,32 This was also mainly related with the electrocatalytic activity of S-GrOP and increasing conductivity of the S-GrOP, including gel electrolyte. 54,55 The formation of three-dimensional porous gelled electrolyte was also supported by the investigation of Warburg impedance value (Table 1).…”

“…This represented the highest electrical conductivity in the gelled composition. 28,32 When the resistance of charge transfer (R ct ) was analyzed, the lowest value was observed in the same electrolyte composition (Table 1). This also supported that the formed fumed silica-based gelled systems by addition of S-GrOP let to decrease the resistance of charge transfer for the formation of lead sulfate from metallic lead.…”

“…31 Although some additives such as metal oxides, polyacrylamide, polyaspartate, propanetriol, and polyols were used in the literature as additives to fumed silica-based gelled electrolyte to improve the conductivity of the gel, there are still needs to improve the conductivity of the fumed silica, including gel electrolyte by using of novel additives. 17,[32][33][34][35][36][37] Indeed, the additives can play a key role for the filling process of the gel in the battery stack without solidification by forming three-dimensional gel structure. At this point, the materials consisting of oxygen, including functional groups such as hydroxyl, carboxylic acid, etc as additives can bring a new perspective to the gel component of the Gel-VRLA batteries.…”