Constructing Quasi-Single Ion Conductors by a β-Cyclodextrin Polymer to Stabilize Zn Anode.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) are a promising technology for large-scale energy storage.
• Challenges with zinc anodes, including corrosion and side reactions, limit AZIB performance and lifespan.
• Stabilizing the zinc anode is crucial for developing practical and durable AZIBs.

Purpose of the Study:

• To develop a protective coating for zinc anodes in AZIBs.
• To create a quasi-single ion conductor to improve zinc ion transport and anode stability.
• To enhance the overall performance and cycle life of AZIBs.

Main Methods:

• Coating zinc anodes with a cyclodextrin polymer (P-CD).
• Investigating the host-guest interactions and hydrogen bonding within the P-CD layer.
• Evaluating the performance of P-CD coated Zn//Zn symmetric cells and Zn//K1.1V3O8 (KVO) full cells.

Main Results:

• The P-CD coating effectively inhibited Zn anode corrosion and side reactions.
• The P-CD layer formed a quasi-single ion conductor, increasing the Zn ion transference number from 0.31 to 0.68.
• P-CD coated Zn//Zn cells showed a 70.6-fold improvement in cycle life at high current densities.
• P-CD coated Zn//KVO full cells maintained 94.5% capacity after 1000 cycles at 10 A g⁻¹, outperforming uncoated cells.

Conclusions:

• Cyclodextrin polymer coatings offer a practical strategy for stabilizing zinc anodes in AZIBs.
• The quasi-single ion conductor effectively suppresses undesirable interfacial phenomena, enhancing battery longevity.
• This approach provides a novel perspective for improving the performance of aqueous zinc-ion batteries.