Intrinsic Ion Concentration Difference Induced Antipolyelectrolyte Effect for Promoting Stability of Zn Anodes.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer safe and cost-effective energy storage.
• However, zinc dendrite formation and interfacial side reactions hinder AZIB performance.

Purpose of the Study:

• To develop a surface modification strategy for AZIB anodes to suppress dendrites and improve electrochemical performance.
• To investigate the role of zwitterionic polymers in controlling ion transport and interfacial reactions.

Main Methods:

• Constructing cross-linked ion channels on zinc anode surfaces using carboxymethyl chitosan (CMCHS) via the antipolyelectrolyte effect.
• Analyzing the impact of CMCHS on ion and electron distribution at the anode/electrolyte interface.
• Investigating the interaction of CMCHS with Zn2+ solvation structures and water molecules.

Main Results:

• CMCHS channels promoted homogeneous ion and electron distribution, suppressing Zn dendrites.
• CMCHS limited the activity of water molecules in the Zn2+ solvation shell.
• Achieved an average Coulombic efficiency of 99.58% in Zn anodes, superior to conventional electrolytes.
• Demonstrated enhanced performance in Zn||V2O5 full batteries.

Conclusions:

• Zwitterionic polymer-induced ion channels effectively mitigate dendrite growth and side reactions in AZIBs.
• The developed CMCHS modification strategy significantly enhances the stability and efficiency of zinc anodes.
• This approach offers a promising pathway for developing high-performance and safe aqueous zinc-ion batteries.