Concentration Optimization of Fumed Silica as Gelator in Lead-acid Batteries

Abstract

The effect of fumed silica (F-SiO 2 ) density on the performance of valve-regulated lead-acid (VRLA) batteries, including the conductivity of H + ions and the diffusion of HSO 4 − ions in the gel electrolyte, the redox capacity of lead, and the evolution of hydrogen and oxygen, have been studied over a wide range of F-SiO 2 densities. The results show that the influence of F-SiO 2 density is not monotonous and always yields a maximum (or inflection) effect at c. 5 to 6 wt% silica, before and after which the effect of F-SiO 2 differ. At lower F-SiO 2 densities, in general, gel formation favours an improvement of the electrochemical behaviour. However, it may produce an adverse effect on the electrochemical properties if F-SiO 2 density further increases. Battery tests at a range between 1 to 3 wt% silica support this observation, in which the discharge capacity, the utilisation of active materials, and the charge efficiency are all enhanced.

The state of understanding of the electrochemical behaviours of a valve-regulated lead–acid battery comprising manganese dioxide-impregnated gel polymer electrolyte

“…In the construction of VRLA batteries, gelling the sulphuric acid solution and subsequently immobilising the electrolyte are crucial phases. 5 Gel polymeric electrolytes are often swollen polymer networks, so they possess both the cohesive properties of solids and the properties of the liquids from the point of view of diffusive transport. 6 In recent years, several polymers like poly(methyl methacrylate), 7 polyacrylamide, 8 calcium alginate, 9 poly(acrylonitrile) (PAN) 10 and poly(vinyl alcohol) 11 have been used for the preparation of gel electrolytes.…”

A Novel Gel Electrolyte for Valve-Regulated Lead Acid Battery

“…This result may be related with interactions of two different gel agents, which have different particle sizes, in gel system consisting of fumed silica-TiO2. The bigger pore size for gelled system can increase the diffusion of mobile ions to electrode surface [27]. Raghavan et al showed possible gel structure of silica particles [28].…”

Graphene-Doped Hydrogels Promoting Ionic Conductivity in Gel-Valve-Regulated Lead Acid Batteries

“…In order to create valve-regulated lead acid (VRLA) batteries, it is crucial to first gel the sulfuric acid solution and then immobilize the electrolyte . Due to their benefits, such as their high power density, good deep-discharge performance, lack of water or electrolyte addition, poor internal resistance, long service life, high current density, ability to operate under a variety of temperature conditions, and vibration resistance in applications, VRLA batteries have been utilized in numerous applications in the industry. , VRLA batteries mainly consist of electrodes, separators, and electrolytes .…”