Anionic Co‐insertion Charge Storage in Dinitrobenzene Cathodes for High‐Performance Aqueous Zinc–Organic Batteries.

Highly active and stable cathodes are critical for aqueous Zn–organic batteries with high capacity, fast redox kinetics, and long life. We herein report para‐, meta‐, and ortho‐dinitrobenzene (p‐, m‐, and o‐DB) containing two successive two‐electron processes, as cathode materials to boost the battery performance. Theoretical and experimental studies reveal that nitro constitutional isomerism is key to zincophilic activity and redox kinetics. p‐DB hosted in carbon nanoflower harvests a high capacity of 402 mAh g−1 and a superior stability up to 25 000 cycles at 5 A g−1, giving a Zn–organic battery with a high energy density of 230 Wh kg−1. An anionic co‐insertion charge storage mechanism is proposed, entailing a two‐step (de)coordination of Zn(CF3SO3)+ with nitro oxygen. Besides, dinitrobenzene can be electrochemically optimized by side group regulation via implanting electron‐withdrawing motifs. This work opens a new window to design multielectron nitroaromatics for Zn–organic batteries. [ABSTRACT FROM AUTHOR]