Nanostructured lead-acid negative electrode with reduced graphene oxide

Aim of this work is to develop a new nano-structured and nano-composite lead acid negative electrode with reduced graphene oxide (rGO). Nanostructured electrodes are fabricated by template electrodeposition of lead nanowires on a lead current collector. A polycarbonate track-etched membrane was used as a template (200 nm mean pores diameter). rGO was deposited on the nanostructured electrode from a graphene oxide (GO) dispersion in acetate buffer solution (ABS) (0.2 g/L). Potentiostatic deposition of rGO at -0.8 V vs. standard calomel electrode (SCE) was performed. Electrode with rGO was tested as negative electrode in cell with 5M sulfuric acid solution, a commercial pasted positive plate, as counter-electrode, and an AGM separator. The electrodes well performed at 2C-rate in deep cycling tests (cut off cell voltage 1.2 V). Its capacity grew during cycling test and reached 232.9 mAh/g, which corresponds to a degree of active material utilization of 90%. Its faradaic efficiency reached 90%. Electrodes with similar morphology were obtained treating the electrodes with a HNO3 solution at -0.8 V vs SCE or with a dispersion of GO in HNO3. These electrodes showed lower active material utilization and lower faradaic efficiency.