Enhanced Cycling Stability in Zn-Ion Batteries Using Aqueous-Organic Electrolyte Solvent Blends.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (ZIBs) offer safety and affordability but face severe degradation issues.
• Existing research has not fully resolved these stability challenges in aqueous electrolytes.
• Solvent-based electrolytes offer stability but compromise safety and cost-effectiveness.

Purpose of the Study:

• To develop a hybrid electrolyte system for ZIBs that combines the safety of aqueous electrolytes with the stability of organic solvents.
• To investigate the impact of a water-DMSO hybrid electrolyte on zinc anode and cathode stability.
• To demonstrate the long-term performance of ZIBs utilizing this novel hybrid electrolyte.

Main Methods:

• Fabrication and electrochemical testing of zinc-ion batteries with a water-DMSO hybrid electrolyte containing Zn(BF4)2 salt.
• Density Functional Theory (DFT) simulations to analyze solvation structures and electrolyte-electrode interactions.
• High-resolution transmission electron microscopy (HRTEM) for analyzing the solid electrolyte interphase (SEI) composition and structure.

Main Results:

• The hybrid electrolyte effectively suppresses zinc metal dissolution and cathode (NVO) degradation.
• A stable solid electrolyte interphase (SEI) is formed on the zinc anode in the hybrid electrolyte.
• Zn||NVO full cells demonstrate stable cycling for over 2000 cycles with approximately 80% capacity retention.

Conclusions:

• Hybrid water-DMSO electrolytes offer a viable strategy to overcome the degradation limitations of aqueous ZIBs.
• This electrolyte system enhances both the safety and electrochemical performance of ZIBs.
• The findings highlight the potential of mixed-solvent electrolytes for developing practical and sustainable energy storage solutions.