Dynamically Ion‐Coordinated Bipolar Organodichalcogenide Cathodes Enabling High‐Energy and Durable Aqueous Zn Batteries

Abstract

AbstractBipolar organic cathode materials (OCMs) implementing cation/anion storage mechanisms are promising for high‐energy aqueous Zn batteries (AZBs). However, conventional organic functional group active sites in OCMs usually fail to sufficiently unlock the high‐voltage/capacity merits. Herein, we initially report dynamically ion‐coordinated bipolar OCMs as cathodes with chalcogen active sites to solve this issue. Unlike conventional organic functional groups, chalcogens bonded with conjugated group undergo multielectron‐involved positive‐valence oxidation and negative‐valence reduction, affording higher redox potentials and reversible capacities. With phenyl diselenide (PhSe‐SePh, PDSe) as a proof of concept, it exhibits a conversion pathway from (PhSe)− to (PhSe‐SePh)0 and then to (PhSe)+ as unveiled by characterization and theoretical simulation, where the diselenide bonds are periodically broken and healed, dynamically coordinating with ions (Zn2+ and OTF−). When confined into ordered mesoporous carbon (CMK‐3), the dissolution of PDSe intermediates is greatly inhibited to obtain an ultralong lifespan without voltage/capacity compromise. The PDSe/CMK‐3 || Zn batteries display high reversibility capacity (621.4 mAh gPDSe−1), distinct discharge plateau (up to 1.4 V), high energy density (578.3 Wh kgPDSe−1), and ultralong lifespan (12 000 cycles) at 10 A g−1, far outperforming conventional bipolar OCMs. This work sheds new light on conversion‐type active site engineering for high‐voltage/capacity bipolar OCMs towards high‐energy AZBs.