Molecule Isolation Protective Interface Formed by Planar Additive for Stable Sodium Metal Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium (Na) metal anodes offer high capacity and low potential for batteries.
• Interface instability, including side reactions and dendrite formation, limits Na metal anode practical use.

Purpose of the Study:

• To investigate zinc phthalocyanine (ZnPc) as an electrolyte additive to improve Na metal anode stability.
• To understand the mechanism by which ZnPc enhances anode performance.

Main Methods:

• Utilizing zinc phthalocyanine (ZnPc) as a planar molecular electrolyte additive.
• Adsorbing ZnPc onto the Na metal anode surface to form a dense molecular layer.
• Evaluating interface stability and cycling performance through electrochemical testing (half-cell and full-cell).

Main Results:

• ZnPc forms a dense molecular layer on the Na anode, suppressing electrolyte side reactions.
• The ZnPc layer homogenizes Na+ flux, significantly reducing dendrite growth.
• Achieved 99.95% average Coulombic efficiency over 350 cycles in a Na metal half-cell.
• Demonstrated excellent stability in a Na||Na3V2(PO4)3 full-cell over 120 cycles.

Conclusions:

• ZnPc additive effectively enhances the interface stability of Na metal anodes.
• The molecular isolation interface formed by ZnPc is crucial for improved cycling performance.
• ZnPc shows significant promise for practical applications in high-performance Na-based batteries.