Life Aging Effect as a Conditioning Process that Regulates the Performance of the Halogen-Free Mg Electrolyte

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Efficient magnesium batteries are critical for next-generation energy storage.
• Electrolyte conditioning significantly impacts battery performance.
• Understanding electrolyte aging is key to optimizing magnesium battery design.

Purpose of the Study:

• To investigate the effect of aging time on halogen-free electrolytes (HFEs) for magnesium batteries.
• To correlate electrolyte conditioning with electrochemical performance.
• To enhance the cycle life and efficiency of magnesium-sulfur (Mg-S) cells.

Main Methods:

• Utilized Mg(NO3)2 in acetonitrile (ACN) and tetraethylene glycol dimethyl ether (G4) as a halogen-free electrolyte (HFE).
• Analyzed aged vs. fresh HFE using characterization techniques to study bulk speciation and Mg2+ solvation.
• Evaluated electrochemical properties including Mg plating/stripping overpotential and bulk resistance.
• Tested Mg-S cells with fresh and aged HFEs at a current density of 0.02 mA cm-2.

Main Results:

• Aging induced apparent changes in bulk speciation and Mg2+ solvation barrier in the HFE.
• Aged HFE exhibited reduced overpotential for Mg plating/stripping and lower bulk resistance compared to fresh HFE.
• Mg-S cells with aged HFE achieved higher specific capacities (586 mA h/g) and improved Coulombic efficiencies.
• Cells with aged HFE demonstrated extended cycle life (up to 30 cycles) versus fresh HFE (short cycle life).

Conclusions:

• Electrolyte aging significantly enhances the electrochemical performance of halogen-free electrolytes.
• The aging process optimizes Mg2+ solvation and reduces resistance, leading to improved Mg-S battery function.
• This study provides a new perspective on how electrolyte conditioning can enhance magnesium battery longevity and efficiency.