Performance improvements of alkaline batteries by studying the effects of different kinds of surfactant and different derivatives of benzene on the electrochemical properties of electrolytic zinc

Abstract

Electrolytic zinc powders were prepared in 12 M KOH, 4 wt.% zinc oxide solutions in the presence of different kinds of surfactant and organic additives using the galvanostatic technique. Then the electrochemical behavior of zinc was investigated using the sweep voltametry technique. Zinc samples electrolyzed in the presence of cationic cetyl trimethyl ammonium bromide (Zn-CTAB), have maximum corrosion rate. Furthermore, scanning electron microscopy revealed the highest surface area. Zinc deposited with anionic surfactants, sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS), have high dendritic and secondary growth. More zinc ions electrolyzed on the cathode electrode in the presence of SDBS compared with SDS. We suppose the Benzene molecule in SDBS changes morphology, thus effects of the benzene molecule is investigated by utilizing several organic compounds during zinc electrodeposition. Naphthalene with 10 pi electrons at two fused rings decreases corrosion rate and needle growth of zinc deposited, compared to benzyl chloride which has 6 pi electrons. Enhanced delocalization of pi electrons by strongly activating group (–NH 2) in the aniline molecule increases the corrosion rate and dendrites compared with benzyl chloride, which has the weakly activating group (–CH 2Cl). The addition of chloro benzene with inactivating and electrodrawing group (–Cl) creates high surface area without any dendritic growth. The effects of electrolyte additives on the electrochemical capacity of AA-sized alkaline Zn-MnO 2 batteries are verified. The addition of Triton X-100 in anode gel resulted in maximum electrical capacity. Anionic (SDBS and SDS) additives gave higher electrical capacity than cationic (CTAB). Also, the reaction mechanism for zinc electrodeposition in alkaline electrolytes and its dependence upon the presence of organic additives are discussed in detail.