Effects of Carboxylates on the Performance of Zn Electrode

Abstract

Zinc is widely used as a negative electrode material for batteries due to its excellent electrochemical properties. Zinc is prone to corrosion and the formation of zinc dendrites cause short circuits of the battery, which leads to reduced battery capacity and shortens the battery's life, hindering its use in weak acidic electrolytes (for example, aqueous Zn-polyaniline batteries). The effects of carboxylates (sodium formate, sodium acetate, sodium propionate, sodium butyrate, sodium valerate, disodium malonate, and disodium succinate) and their concentrations on zinc electrode performance were studied with electrochemical methods to improve the zinc electrode activity for long-life Zn-polyaniline batteries. It was found that the ability of inhibiting corrosion of the zinc electrode is better in the aqueous electrolyte containing 0.2 M disodium malonate. The charge/discharge performance of a Zn-polyaniline battery electrodeposited with polyaniline on a carbon substrate is carried out in the aqueous electrolyte. the results show that the initial discharge specific capacity of the polyaniline in the Zn-polyaniline battery is as high as 131.1 mAh¨g´1, and maintains a discharge specific capacity of 114.8 mAh¨g´1 and a coulombic efficiency over 92% after 100 cycles at a charge/discharge current density of 1 A¨g´1 in the voltage range of 1.5-0.7 V.