Zn-Alloying Sites with Self-Adsorbed Molecular Crowding Layer as a Stable Interfacial Structure of Zn Electrodes

Abstract

Rechargeable aqueous zinc (Zn) metal batteries (ZMBs) have gained tremendous attention because of their intrinsic safety and low cost. However, the lifespan of ZMBs is seriously limited by severe Zn dendritic growth in aqueous electrolytes. Despite the feasibility of Zn deposition regulation by introducing Zn-alloying sites at the Zn plating surface, the activity of the Zn-alloying sites can be seriously reduced by side reactions in the aqueous environment. Here, we propose a facile but efficacious strategy to reinforce the activity of the Zn-alloying sites by introducing a low quantity of polar organic additive in the electrolyte that can be self-adsorbed on the Zn-alloying sites to form a molecular crowding layer against the parasitic water reduction during Zn deposition. As a consequence, stable cycling of the Zn anode can be maintained at such a multifunctional interfacial structure, arising from the synergism between the seeded low-overpotential Zn deposition on the stabilized Zn-alloying sites and a Zn2+ redistributing feature of the self-adsorbed molecular crowding layer. The interfacial design principle here can be widely employed due to the great variety of Zn-alloy and polar organic materials and potentially be applied to improve the performance of other aqueous metal batteries.

Spraying amorphous carbon coated zinc to prepare powder-based anodes for long-life zinc-ion batteries

“…So far, several strategies have been proposed to address these issues caused by metallic Zn foil, such as Zn alloy design, host structural design, and surface modification. 5–12 Despite great progress, the Zn foil anode also has to be used in significant excess to maintain the supply during its consumption by side reactions, which erodes the overall energy density at the cell level. 13–17 Therefore, new opportunities are emerging in zinc powder anodes because of their low-cost, good tunability and easy-processability.…”

Organic Fillers Regulating the Solvation Structure of Zinc Ions in Aqueous Electrolytes for High-Stability Zn2+/Li+ Hybrid Batteries

“…are relatively mature, but the anode materials are difficult to be used in practical applications . As for AZIBs, zinc metal anodes have attracted tremendous attention because of a −0.76 V redox potential [vs standard hydrogen electrode] and high reversibility, but the selection of cathode materials is limited due to the difficulty of migration of divalent Zn 2+ . − In order to overcome the shortcomings of single-type battery systems, hybrid ion batteries have been proposed and gradually become the research focus of aqueous ion batteries.…”