Bifunctional additive: Lead dioxide nanoparticle-doped graphene oxide composites for the preparation and performance study of positive electrodes in lead-carbon batteries

Lead-carbon batteries (LCBs) possess the dual functions of supercapacitors and lead-acid batteries (LABs), which can meet the demand for renewable energy and in mild hybrid electric vehicles (HEVs) for energy storage and short-term high-rate charging and discharging. With the cycle of high-rate partial state-of-charge (HRPSoC), irreversible sulfation of the positive electrode becomes increasingly prominent and serious, resulting in low discharge capacity and short cycle life. In this study, to reduce the sulfation of the positive plate and improve the battery capacity and cycle life, a lead dioxide nanoparticle-doped graphene oxide (nano-PbO2/GO) composite material with dual functions of conducting and nucleating was prepared by a hydrothermal method as a positive electrode additive. The results show that the addition of nano-PbO2/GO promotes the formation of a threedimensional short rod-like structure of PbO2 nanoparticles in a dendritic arrangement, accelerates the generation of new phases and inhibits the growth of bulk PbSO4. Moreover, the positive plate with nano-PbO2/GO exhibits good electrochemical activity to maintain the stability and reversibility of the electrode redox reaction. Finally, the initial discharge specific capacity of the LCBs with nano-PbO2/GO is increased to 153.85 mAh/g, and the HRPSoC cycle life is up to 15658 cycles at a 2 C discharge rate. Overall, the dual functions of nano-PbO2/GO greatly alleviate battery sulfation and provide a reference for improving the performance of LCBs by modifying the electrode structure.