Positive electrode material in lead-acid car battery modified by protic ammonium ionic liquid

Abstract

The aim of the presented study was to develop a feasible and technologically viable modification of a 12 V lead-acid battery, which improves its energy density, capacity and lifetime. The proposed solution promotes the addition of a protic ammonium ionic liquid to the active mass of the positive electrode in the lead-acid battery. The experiments included the synthesis and characterisation of several protic ammonium-based ionic liquids, which differed in terms of the length of the side chain in the cation. A three-stage procedure of the battery test was proposed. First, a laboratory model with a Pb-Ca-Sn alloy as a working electrode and ionic liquids as additives to the electrolytes enabled the selection of the best modifier. Addition of the best-studied ionic liquid, N,N-dimethylhexadecylammonium sulfate, suppressed the corrosion of current collector material by approx. 70% and increased the overpotential of hydrogen evolution reaction. Afterwards, tests on 2 V model lead-acid cells were carried out to compare the various concentrations of the ionic liquid in the active mass. Finally, tests on 12 V lead-acid batteries with 0.5% of protic ionic liquid were performed to evaluate the final influence on the full, industrial product.