Potassium Polyacrylate-Based Gel Polymer Electrolyte for Practical Zn-Ni Batteries

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Zinc-nickel batteries (ZNBs) offer high energy density and safety, making them suitable for uninterrupted power supply (UPS).
• Commercialization of ZNBs is hindered by short cycle life due to Zn anode issues like shape change, corrosion, and dendrite formation.

Purpose of the Study:

• To develop a flexible and durable gel polymer electrolyte (GPE) to address Zn anode degradation in ZNBs.
• To improve the cycling life, stability, and overall performance of ZNBs for practical applications.

Main Methods:

• Fabrication of a potassium polyacrylate (PAAK)-KOH GPE with a highly porous structure.
• Characterization of the GPE's properties, including water retention, ionic conductivity (0.918 S cm⁻¹), and electrochemical stability.
• Evaluation of the GPE's performance in ZNBs, assessing cycling life, corrosion resistance, and performance under float charge conditions.

Main Results:

• The PAAK-KOH GPE demonstrated excellent water retention, ionic conductivity, and a wide electrochemical voltage window.
• The GPE effectively stabilized the Zn anode interface, inhibiting dendrite formation and uneven deposition.
• ZNBs utilizing the GPE achieved a prolonged cycling life of 776 hours, a shelf life exceeding 431 hours, and stable float charge performance over 400 hours at 60 °C.

Conclusions:

• The simple-to-prepare PAAK-KOH GPE is a viable solution for enhancing ZNB performance and longevity.
• This GPE is suitable for large-scale production and demonstrates significant potential for commercial ZNB applications.
• The developed GPE effectively overcomes critical Zn anode limitations, paving the way for more reliable ZNB technology.