A New Low-Rate Stable Hydrogel Cathode for Aqueous Zn-ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (ZIBs) offer safe and cost-effective large-scale energy storage.
• Practical ZIB application is limited by poor cathode stability and insufficient electrochemically active sites (EAS).

Purpose of the Study:

• To develop a hydrogel-based cathode for ZIBs to enhance cycle stability and active site utilization.
• To address cathode dissolution and limited EAS in ZIBs.

Main Methods:

• Fabrication of a hydrogel cathode using ammonium vanadate, carbon black, and a Zn-ion-conducting carboxymethyl chitosan-acrylamide hydrogel matrix doped with Zn(ClO4)2.
• Electrochemical testing of the ZIB with the novel hydrogel cathode.

Main Results:

• The hydrogel cathode established a continuous Zn-ion-conducting network, maximizing EAS density.
• The ZIB demonstrated excellent cycling stability: 77% capacity retention after 2000 cycles at 1 A g⁻¹ and 75% after 1400 cycles at 0.5 A g⁻¹.
• The hydrogel matrix effectively suppressed active material dissolution.

Conclusions:

• The hydrogel cathode design represents a significant advancement in stabilizing ZIB cathodes.
• This strategy paves the way for developing durable and high-performance aqueous zinc-ion batteries for long-duration energy storage.