Reduced graphene oxide as an additive in advanced lead-acid batteries

The addition of reduced graphene oxide (rGO) to the negative active material (NAM) of advanced flooded lead-acid batteries can enhance battery life under partial state of charge (PSoC) conditions. Hence, we sought to evaluate the effects of different rGO concentrations (0.20%, 0.75%, and 1.40%) on battery performance. The rGO was synthesized using an improved Hummers method. Microstructural characterization of rGO involved X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and other techniques. Electrochemical characterization, including cyclic voltammetry and electrochemical impedance spectroscopy, confirmed rGO's superior specific capacitance compared to conventional carbon additives. Capacitance studies showed that approximately 38% of rGO's total capacitance was due to pseudocapacitance. Battery performance tests under PSoC conditions revealed that NAM containing 0.20% rGO exhibited a 21% increase in cycle life and a 6.1% higher C ₂₀ specific capacity than control plates with advanced carbon black. However, higher rGO concentrations (0.75% and 1.40%) led to reduced performance due to increased faradaic processes involving hydrogen evolution. These findings suggest that rGO can be an effective additive for advanced flooded lead-acid batteries, provided its concentration is carefully optimized to maximize benefits while minimizing adverse effects.