Stabilizing Lithium Anode Using A Bifunctional Redox Mediator β-Bromostyrene For Lithium-Oxygen Batteries

Due to their potential for high specific energy, lithium-oxygen (Li-O2) batteries have garnered significant interest as a rechargeable power storage device. However, because of the instability inherent to the lithium metal anode, the significant charging overpotential poses substantial challenges, restricting the commercial application development of Li-O2 battery. In this study, β-Bromostyrene is introduced as a novel bifunctional redox mediator (RM) based on these two problems. During the charging cycle of Li-O2 batteries, β-Bromostyrene promotes the decomposition of Li2O2 by releasing Br−, effectively lowering the charging overpotential. Meanwhile, β-Bromostyrene is likely to form polystyrene oligomers with benzene rings, which enhances the quality and stability of the solid electrolyte interphase layer and efficiently suppress the formation of lithium dendrites on the lithium metal anode surface. Consequently, the lithium-oxygen battery incorporating β-Bromostyrene as an RM is able to cycle stably for 140 cycles.