Constructing Three-Dimensional Topological Zn Deposition for Long-Life Aqueous Zn-Ion Batteries

Uniform and compact Zn deposition-dissolution is essential to achieve high Coulombic efficiency and long lifespan for Zn anodes. More attention has been commonly focused on the suppression of macroscopic Zn dendrites in the previous reports. The rational control of the microstructure of Zn deposition to prevent the intrinsic volume expansion and pulverization of Zn metal so as to stabilize Zn anodes is less discussed. Herein, we construct a three-dimensional topological Zn deposition at the nanoscale through an in situ electrochemical process in the optimal hybrid aqueous electrolyte. The topological electrode structure can efficiently accommodate microscopic strain and volume variation and thus largely preserve the macroscopic integrity and electrical contact of Zn anodes, leading to enhanced reversibility and stability. With the unique topological structure of Zn deposition, the Coulombic efficiency of Zn anodes could reach >99.9% with excellent cycling over 1182 h at 2 mA cm-2 and 2 mA h cm-2 (Zn utilization: 11.4%). The evolution of dead Zn during repeated cycling is first investigated using a homemade semiquantitative analysis method to determine the critical short slab for aqueous Zn batteries under the practical application. This work provides an insightful method to regulate the microscopic morphology of Zn deposition for high-performance Zn batteries.

Automated summary

This study constructs a topological structure of nano-scale zinc deposition through an in situ electrochemical process in an aqueous electrolyte. The topological electrode structure has the ability to efficiently accommodate microscopic strain and volume variation, significantly improving the reversibility and stability of zinc anodes.