Trap-anchor-catalysis design in boosting halogen chemistry for high-performance aqueous zinc-iodine batteries

Abstract

The polyiodide shuttle effects and sluggish iodine redox kinetics significantly impede the broader applications of aqueous zinc-iodine batteries (AZIBs). Therefore, exploring high-capacity host materials with “trap-anchor-catalysis” sites is of great significance to the development of AZIBs. Herein, hydrogen-rich host materials (labeled as CCAs) with a high specific surface area and microporous structure were synthesized using a self-template method, which features the “trap-catalysis” sites (calcium hydroxide) in-situ embedded within the carbon skeletons. Benefiting from the integrated advantages of strong confinement and enhanced catalysis behaviors, this host material enables high conversion efficiency and rapid redox kinetics of I<inf>2</inf>/I-, thus achieving high utilization of the iodine cathode and a corrosion-free zinc anode. Moreover, the reversible rehybridization of sp2-C to sp3-C endows the host material with additional “active-anchor” sites, facilitating a more efficient reaction pathway and faster electron transfer in halogen chemistry. The resulting I<inf>2</inf>@CCA-800 cathodes deliver a capacity of ∼210 mAh g−1 at 0.5 A g−1 and a stable cycling life of 40,000 cycles (86.7 % retention at 10 A g−1). More importantly, the CCA-800 host material possesses good reusability; after iodine reloading, the recycled devices maintain a capacity of ∼110 mAh g−1 at 5 A g−1 over 10,000 cycles. This study provides valuable insights into the rational structural design of hydrogen-rich host materials for efficient halogen chemistry in AZIBs.