Polyxylylviologen Chloride as an Organic Electrode Material for Efficient Reversible Chloride-Ion Storage

Organic molecules such as viologens with a nitrogen redox center show promise as efficient anion storage materials in rechargeable batteries. However, the high solubility of viologens in liquid electrolytes limits their wide electrochemical application. Herein, an insoluble polymerized polyxylylviologen chloride (PXVCl₂) is first developed as a chloride ion storage electrode in chloride ion batteries. The as-prepared PXVCl₂electrode exhibits a competitive discharge capacity of 140 mA h g^-1(86% of the theoretical discharge capacity) compared to that of the previously reported organic conducting polymer electrodes. The incorporation of graphene in the PXVCl₂material achieves significant improvements in reaction reversibility and rate capability of the PXVCl₂electrode. Importantly, the nitrogen redox reactions based on chloride ion transfer of the PXVCl₂electrode are demonstrated.