Surface Transformation Enables a Dendrite‐Free Zinc‐Metal Anode in Nonaqueous Electrolyte

Abstract

Significant challenges remain in developing rechargeable zinc batteries mainly because of reversibility problems on zinc‐metal anodes. The dendritic growth and hydrogen evolution on zinc electrodes are major obstacles to overcome in developing practical and safe zinc batteries. Here, a dendrite‐free and hydrogen‐free Zn‐metal anode with high Coulombic efficiency up to 99.6% over 300 cycles is realized in a newly designed nonaqueous electrolyte, which comprises an inexpensive zinc salt, zinc acetate, and a green low‐cost solvent, dimethyl sulfoxide. Surface transformation on Cu substrate plays a critical role in facilitating the dendrite‐free deposition process, which lowers the diffusion energy barrier of the Zn atoms, leading to a uniform and compact thin film for zinc plating. Furthermore, in situ electrochemical atomic force microscopy reveals the plating process via a layer‐by‐layer growth mechanism and the stripping process through an edge‐dissolution mechanism. In addition, Zn||Mo6S8 full cells exhibit excellent electrochemical performance in terms of cycling stability and rate capability. This work presents a new opportunity to develop nonaqueous rechargeable zinc batteries.

Addition of Dioxane in Electrolyte Promotes (002)-Textured Zinc Growth and Suppressed Side Reactions in Zinc-Ion Batteries

“…13 The dendrite growth and side reactions resonate with each other, seriously limiting the practicality of ZIBs as a feasible energy storage system. 14 Intense research efforts have been devoted to improve the stability and reversibility of Zn anodes, including anode surface treatment, 15,16 electrolyte optimization, 17,18 and structural design. 19 Among these strategies, electrolyte optimization has been shown to be promising due to the simple manufacturing and low cost.…”

“…Intense research efforts have been devoted to improve the stability and reversibility of Zn anodes, including anode surface treatment, , electrolyte optimization, , and structural design . Among these strategies, electrolyte optimization has been shown to be promising due to the simple manufacturing and low cost.…”

In situ characterizations for aqueous rechargeable zinc batteries

“…[97,98] Huang et al studied the zinc deposition/ dissolution of Cu in the organic electrolyte. [94] The EC-AFM imaging in Figure 5b shows that the zinc nuclei grows into the nanosheet after the alloying and forming process. In addition, the typical hexagonal zinc deposits exhibit an edge angle of 120°after electrodepositing for 1200 s in Zn(OAc)-DMSO electrolyte, which is followed by edge-to-center zinc stripping from the substrate during the charging process.…”

“…[93] Figure 5a shows the schematic Reproduced with permission: Copyright 2022, John Wiley and Sons. [94] (c) The (002) oriented hexagonal surface of zinc deposition on the HOPG. (d) Zinc hexagonal with a rougher top surface and blurred hexagonal edges.…”

“…[95] illustration of the in situ electrochemical AFM (EC-AFM). [48,94] The laser focuses on the back of the cantilever attached to a probe. The displacement of the reflected laser induced by the scanning probe is collected by the detector, which reveals the changes in visualized topography and mechanical information of the characterized area during the electrochemical process.…”