Insight into the performance of valve-regulated lead-acid battery using sodium salt of poly(4-styrene sulfonic acid-co-maleic acid)-poly(vinyl alcohol) gel electrolyte

The polymer gel electrolyte is a major part of valve-regulated lead-acid (VRLA) batteries. This research work narrates the formulation of a novel gel system using poly(vinyl alcohol) (PVA) and poly(4-styrene sulfonic acid-co-maleic acid) sodium salt (PSSAMA_Na) for VRLA batteries. The crosslinking of PVA and PSSAMA_Na is confirmed by using Fourier transform infrared spectroscopy. The polymer gel electrolytes (PGEs) of PVA and PSSAMA_Na are prepared by varying the weight ratio of PSSAMA_Na and designated as PE to PE-4 with varying the weight ratio of PSSAMA_Na from 5 to 20 %. Among the entire developed gel systems, cyclic voltammetry and electrochemical impedance spectroscopy suggested that PE-2 with a weight ratio of 10 % exhibits high electrochemical performance. The galvanostatic charge-discharge tests are accomplished on the prototype battery of the optimized gel system and the highest capacity of 2.517 × 10−4 Ah at a current density of 0.5 mA cm−2 is achieved with an admirable capacity retention of 97.14 % over 500 cycles. The developed novel PVA-PSSAMA gel electrolyte can be used for low-cost commercial VRLA batteries.