Reduced-graphene-oxide-enhanced nanostructured lead–acid batteries: Performance optimization and life cycle assessment

The integration of nanostructured materials into energy storage systems is a promising approach to improve lead–acid battery performance. This study examines the effect of reduced graphene oxide additives on twelve-volt lead–acid batteries, focusing on key metrics including energy density, charge-discharge efficiency, and cycle life. Batteries with and without reduced graphene oxide were tested in five-molar sulfuric acid using an absorbed glass mat separator in a zero-gap configuration. The electrodes were subjected to deep cycling with a low cut-off voltage, and charge–discharge tests were performed at a high rate corresponding to ten times the nominal capacity rate. The results show that adding reduced graphene oxide improves charge retention and stabilizes battery behavior under high-rate operation. Scanning electron microscopy revealed substantial differences in electrode morphology before and after cycling: the initial nanowire structure was no longer observed and the surface was largely covered by lead sulfate crystals, while a porous morphology was retained. Post-cycling X-ray diffraction and Raman spectroscopy confirmed that not all active material converted to lead sulfate under the applied conditions. Additionally, the environmental impact of the manufacturing process was assessed using Life Cycle Assessment methodology for laboratory-scale electrodeposited electrodes, revealing that reduced graphene oxide has a limited environmental impact while enhancing performance.