Stable Zinc Anodes Enabled by a Zincophilic Polyanionic Hydrogel Layer.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc (Zn) metal anodes are crucial for aqueous batteries but suffer from dendrite growth, hydrogen evolution, and surface passivation, limiting their practical use.
• These issues compromise battery safety and cycle life, necessitating advanced protection strategies for Zn anodes.

Purpose of the Study:

• To develop a protective layer for Zn anodes that mitigates dendrite formation and hydrogen evolution.
• To enhance the electrochemical performance and stability of aqueous Zn batteries.

Main Methods:

• A polyanionic hydrogel film, functionalized with zincophilic groups, was synthesized and applied to the Zn anode surface using a silane coupling agent (Zn-SHn).
• The protective layer's effect on zinc ion flux, hydrogen evolution reaction, and Zn deposition/stripping was investigated.
• A full aqueous battery cell (Zn-SHn anode vs. NaV3O8·1.5H2O cathode) was assembled and tested for cycling performance.

Main Results:

• The hydrogel film effectively uniformized zinc ion transport and suppressed hydrogen evolution.
• Stable and reversible Zn stripping/plating was achieved over extended cycling at high current densities.
• The full cell demonstrated a high capacity of 176 mAh g⁻¹ with 67% retention after 4000 cycles at 10 A g⁻¹.

Conclusions:

• The polyanionic hydrogel film serves as an effective protective layer for Zn anodes, addressing key limitations in aqueous battery technology.
• This strategy offers a promising approach for designing stable, high-performance, and safe aqueous batteries utilizing Zn anodes.