Effect of formic acid as an electrolyte additive on the performance of a 2-V lead-acid cell

Additives are very important to enhance the performance of lead-acid batteries. In this paper, formic acid is used as an electrolyte additive to study its effect on battery performance. The results show formic acid has an opposite effect on the electrochemical properties of pure lead at positive and negative potentials. Besides, formic acid can make more active materials participate in the reaction, increase the rate of conversion of lead to lead sulfate, and reduce the internal resistance of the battery. Moreover, formic acid batteries exhibit better rate performance and higher specific discharge capacity than the blank. Especially, when the 0.5 wt% formic acid is used, the discharge capacity can reach 87.0 mAh g −1 when it is discharged at 400 mA g −1 . After 1200 cycles of charge and discharge at a current density of 100 mA g −1 , the specific discharge capacity is still 68.1 mAh g −1 , which is 1.42 times higher than that of blank cells.