Enhancement of valve-regulated lead-acid battery performance using polyaniline additive in fumed silica–based gel electrolyte

In this study, polyaniline (PANi) powder is prepared using the chemical oxidative polymerization method, which, to the best of our knowledge, is reported for the first time in the literature as an additive in the fumed silica–based gel electrolyte of a valve-regulated lead-acid battery. Electrochemical analysis techniques, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel analysis, are employed to optimize the PANi powder ratio and other parameters influencing the performance of the gel electrolyte. The optimal PANi content in the gel system is determined to be 0.6 wt%. The stirring time and stirring rate are set at 30 min and 500 rpm, respectively. Cyclic charge–discharge tests are performed to assess the battery performance of different gel systems, with capacities measured as 52.75, 45.75, and 35 mAh/g at a charge–discharge current density of 5 mA/g for the PANi gel electrolyte, fumed silica–based gel electrolyte, and sulfuric acid (aqueous electrolyte), respectively. The results of long-cycle tests conducted for the same gel systems show that the retention capacity of the PANi gel electrolyte system is 82% after 200 cycles at a current density of 10 mA/g.