A self-assembled 2-hydroxyphosphonoacetic acid protective layer enables dendrite-free Zn anodes

Area of Science:

• Materials Science
• Electrochemistry
• Surface Chemistry

Background:

• Zinc-based batteries are promising for energy storage.
• Zinc dendrite growth and water-related side reactions hinder their performance and safety.
• Developing stable protective layers is crucial for enhancing zinc anode stability.

Purpose of the Study:

• To construct a stable self-assembled protective layer on the zinc surface.
• To investigate the effectiveness of the 2-hydroxyphosphonoacetic acid (HPAA) layer in suppressing zinc dendrite growth and side reactions.
• To evaluate the electrochemical performance of the modified zinc anode in symmetric and full cells.

Main Methods:

• Self-assembly of a 2-hydroxyphosphonoacetic acid (HPAA) layer on a Zn surface via chelation.
• Electrochemical testing of Zn symmetric cells to assess cycling lifetime.
• Assembly and testing of Zn-HPAA//V2O5 full cells to evaluate capacity retention and long-term stability.

Main Results:

• A stable HPAA protective layer was successfully constructed on the Zn surface.
• The HPAA layer effectively inhibited water-related side reactions and suppressed Zn dendrite growth.
• The Zn-HPAA-1h anode exhibited a long cycling lifetime of 650 h in a symmetric cell at 30.0 mA cm⁻².
• The Zn-HPAA-1h//V2O5 full cell maintained a high capacity of 154.1 mA h g⁻¹ after 1000 cycles at 2 A g⁻¹.

Conclusions:

• The HPAA protective layer provides an effective strategy for stabilizing the Zn anode.
• This approach significantly enhances the cycling stability and performance of zinc-based batteries.
• The study offers a new pathway for developing dendrite-free and high-performance zinc anodes for energy storage applications.