Dynamic Regulation for the Well-Distribution of Electrons and Zn²⁺ Ions Achieving Uniform Zn Redox in Ah-Scale Pouch Cells.

Abstract

Uneven distribution of the electric field and zinc ion (Zn²⁺), and crosstalk effects all lead to irreversible redox of Zn, eventually accelerating the failure of various Zn-metal energy storage devices, especially Ah-scale pouch batteries. This study pioneers a strategy to dynamically regulate electrons and Zn²⁺ ions for uniform Zn redox, in which a series of additive molecules with varying electron delocalized spaces is designed to verify this dynamic regulation mechanism. Due to the large electron delocalized space, the additives with delocalized π-bonds and ‒COOH form a stable molecular layer for the Zn anode. This layer can effectively prevent side reactions and dynamically regulate the arrangement of electrons and Zn²⁺ ions by driving electrons to flow among conjugated atoms and functional groups, ultimately evening out the electric field and reaction sites of Zn²⁺ ions during the Zn redox process. Thanks to this dynamic regulation, the Ah-scale Zn//I₂ pouch cell exhibits a high capacity of 1.473 Ah (188.7 Wh kg^-1) at 2 mA cm^-2 and outstanding rate performance. This dynamic regulation also presents great compatibility with Zn-manganese pouch cells and Zn-bromine cells. This work deepens the understanding of the regulation mechanism for highly reversible Ah-scale AZIBs.