Study of Graphene as a Negative Additive for Valve-Regulated Lead-Acid Batteries Working under High-Rate Partial-State- Of-Charge Conditions

To extend the applications of graphene and improve the cyclic life of valve-regulated lead acid (VRLA) batteries applied in hybrid electric vehicles, graphene has been added to negative active materials of the VRLA batteries. The influence of graphene on the negative electrodes of valve- regulated lead-acid batteries during high-rate partial-state-of-charge cycling has been investigated by galvanostatic charge/discharge tests, scanning electron microscopy, X-ray diffraction and cyclic voltammetry. Results suggest that the addition of graphene in negative materials can diminish the charge cut-off voltage, boost the discharge cut-off voltage and improve the cyclic life of the VRLA batteries in high-rate partial-state-of-charge cycling. The superior electrochemical performance could be ascribed to the inhibition effect of graphene on the growth of lead sulfate. Therefore, graphene can be a promising negative additive for VRLA batteries.