Macromolecules Promoting Robust Zinc Anode by Synergistic Coordination Effect and Charge Redistribution

Abstract

Zn dendrite formation is the main obstacle to commercializing aqueous zinc–ion batteries (ZIBs). α-cyclodextrin (α-CD) is proposed as an environmentally friendly macromolecule additive in the ZnSO4-based electrolyte to obtain stable and reversible Zn anodes. The results show that α-CD molecules’ unique 3D structure can effectively regulate the mass transfer of the electrolyte components and isolate the Zn anode from H2O molecules. The α-CD provides abundant electrons to the Zn (002) crystallographic plane, which induces charge density redistribution. Such an effect relieves the reduction and aggregation of Zn2+ cations while protecting the Zn metal anode from water molecules. Finally, a small amount of α-CD additive (0.01 M) can enhance the performance of Zn significantly in Zn||Cu cells (1980 cycles with 99.45% average CE) and Zn||Zn cells (8000 h ultra-long cycle life). The excellent practical applicability was further verified in Zn||MnO2 cells.