Reduced graphene oxide coated with amorphous lead as positive additive for enhanced performance of lead–carbon batteries

Abstract

Composites of reduced graphene oxide coated with amorphous lead (Pb/rGO) were prepared by electrostatic adsorption and hydrothermal methods, and used as positive additives for lead–carbon batteries to enhance discharge specific capacity and cycle life under high-rate partial-state-of-charge (HRPSoC) of batteries. Amorphous Pb inhibits the oxygen evolution reaction (OER) that occurs on the surface of reduced graphene oxide (rGO) and increases the specific capacitance of the positive active material (PAM). In addition, the presence of amorphous Pb enhances the affinity of rGO to PAM, which avoids the separation of additive and PAM during the cycling process. Pb/rGO additives can act as pore forming agents and significantly increase the specific surface area of PAM, which enables the electrolyte to fully react with PAM to inhibit the overgrowth of PbSO₄ crystals. Thus, Pb/rGO additives help to improve the electrochemical performance of batteries. To be specific, when the Pb/rGO additive content is 0.7 wt%, battery showed the best discharge specific capacity (102 mAh/g) and cycle life (18,104 cycles), which is 117% and 104% higher than that of blank battery, respectively. And the rate capability is also improved compared to its counterpart. In short, the Pb/rGO composite material has potential application value in lead–carbon batteries.