Effect of orange peel derived activated carbon as a negative additive for lead-acid battery under high rate discharge condition.

In the present study, the effect of orange peel derived activated carbon (OPAC) as an additive to the negative active material in lead acid battery cell was investigated and compared with control cell containing carbon black (CB). The electrochemical performance of negative electrodes is measured by cyclic voltammetry, impedance spectroscopy, galvanostatic charge-discharge. The surface area, crystal structure and morphology are characterized by Brunauer–Emmett–Teller, X-ray diffraction, Raman spectroscopy, transmission electron microscopy and scanning electron microscopy, respectively. OPAC carbon with high surface area (2160 m²/g) and meso/microporous structure exhibits significant influence on the electrochemical kinetics of the negative electrode. The lead acid cells containing OPAC show enhanced discharge performance under high rate discharge conditions, and charge acceptance, when compared to CB containing control cell. The optimum composition for the best electrochemical performance is determined at 0.1 wt% for OPAC. Cell with 0.1 wt.% OPAC show better discharge characteristics (with ~ 20% increase in average discharge capacity) than cell with 0.25 wt.% CB at C₂ discharge rate. Oxygen and hydrogen gassing potential delayed by 31 and 37 minutes, respectively, in a cell comprising 0.1 wt.% OPAC, indicating the efficient charging process (PbSO₄ to Pb conversion) at C₂ rate. Lead acid cell infused with 0.1 wt.% OPAC showed ~ 89% increase in charge acceptance, over control cell containing CB. The inclusion of high specific surface area OPAC linearly increases the redox activity (Pb/PbSO₄) especially at high discharge rates, and suppress the sulfation of negative active material.