High Performance Aqueous Zinc Organic Batteries
Highly active and stable anodes are key to the development of aqueous organic zinc batteries with high capacity, fast redox kinetics and long life.
Key points of the article
1) Theoretical calculations reveal the important effect of nitro structural isomerization on the aromatic backbone, which alters the intramolecular electron distribution and the main body energy levels, leading to different zincophilic activities and redox kinetics. A comprehensive study by the researchers elucidated the two-step redox reaction of cationic Zn(OTF)+ (trifluoromethanesulfonate, OTF -= CF3SO3-) complexes in nitroaromatic-based cathodes. Completely different from alkali metal ion batteries, this charge storage mechanism prevents nitroaromatics from rearranging their configurations and sharing Zn2+ with neighboring nitro groups, thus reducing desolvation energy loss and maintaining structural stability during the electrochemical reaction.
(2) Thanks to the stable and robust multi-electron redox, p-DB (p-DB@CF) encapsulated in carbon nanoflowers provides a large reversible capacity of 402 mAh g-1 as an organic cathode and excellent stability up to 25,000 cycles, which results in a zinc-organic battery with a high energy density of 230 Wh kg-1. In addition, the electrochemical index of nitroaromatics can be controlled by modulating the side groups with electron-absorbing/electron-pushing functional substituents on the nitrobenzene backbone.
1) The authors first summarize in detail the ion storage mechanism of aqueous ZOBs and then present the main methods for analyzing their dynamic behavior.
2) Subsequently, based on the ion storage mechanism and molecular structural features, we systematically summarize the recent advances and design strategies of existing organic electrode materials, including n-type, p-type and bipolar electrode materials. Subsequently, we summarize for the first time the main synthesis strategies of these organic electrode materials.
3) The authors highlight the existing improvement strategies for aqueous ZOBs to achieve higher electrochemical performance in terms of their specific capacity, operating voltage, multiplicative performance, and cycle life, as well as lower preparation cost.
4) Finally, the authors discuss the challenges faced by aqueous ZOBs to realize practical applications. Reasonable perspectives and promising exploration directions for aqueous ZOBs are presented to guide the research towards practical applications and realize a greener rechargeable world.
