High-Performance Zinc–Iodine Battery Cathode Enabled by Silver Nanoparticles on Carbon Nanotube-Doped Reduced Graphene

Owing to their excellent safety characteristics, low manufacturing cost, and remarkable theoretical capacity, aqueous zinc–iodine batteries (AZIBs) are a promising system for future energy storage applications. Nevertheless, the practical deployment of these batteries is greatly restricted by sluggish redox reaction kinetics and the polyiodide intermediate migration, known as the shuttle effect. In this study, we design a three-dimensional carbon nanotube (CNT)-doped reduced graphene (RGO) loaded with silver nanoparticles (Ag NPs) (Ag NPs/CNT-RGO) as a cathode host for AZIBs. The interconnected conductive network constructed from RGO and CNT provides efficient electron/ion transport channels, while uniformly dispersed Ag NPs on the surface of CNT-RGO act as catalytic centers to improve the iodine redox reaction rate and suppress polyiodide migration. Benefiting from these synergistic effects, Ag NPs/CNT-RGO can serve as a high-quality iodine cathode carrier material. The I2@Ag NPs/CNT-RGO cathode delivers a high capacity of 168 mAh g–1 at 20 C and demonstrates outstanding cycling durability, retaining 90% of its initial capacity after 60000 cycles. This study elucidates the catalytic role of Ag NPs in promoting reversible iodine redox chemistry and provides a new high-performance cathode design strategy for AZIBs.