Na2EDTA chelating agent as an electrolyte additive for high performance lead-acid batteries

Abstract Addition of 0.5 wt % ethylene diamine tetraacetic acid based sodium salt (Na2EDTA) chelating agent to lead-acid battery (LAB) electrolyte improves the conductance, reduces significantly the battery formation time from 3 cycles to 1 cycle due to decrease in hard sulfation, increases C rate performances (>20% increase in capacity at > 3C rates), and cycling efficiency of the battery. We present here the electrochemical performance of the conventional and corresponding Na2EDTA additive lead-acid cells by galvanostatic charge-discharge cycling, I-V characteristics, cyclic voltammetry and surface chemical aspects by using electrochemical impedance, X-ray diffraction, and scanning electron microscopy. The results indicate that the morphology of PbSO4 layer and particle size changes from spherical to rod like morphology under the influence of Na2EDTA chelating agent. In overall, addition of Na2EDTA chelating agent enhances charge acceptance, 10–20% improvement in discharge capacity and cycle life of the lead acid batteries. The superior electrochemical performance is owing to the dissociation of PbSO4 in the presence of Na2EDTA chelating agent.