A Passivation-Free Solid Electrolyte Interface Regulated by Magnesium Bromide Additive for Highly Reversible...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Magnesium battery chemistry requires electrolytes compatible with electrodes.
• Conventional electrolytes form passivation layers on Mg anodes, necessitating additives like MgCl₂.
• MgCl₂ additives cause corrosion and limit anodic stability in Mg batteries.

Purpose of the Study:

• To comparatively study Mg halides as electrolyte additives.
• To develop a novel electrolyte formulation for improved Mg battery performance.
• To investigate the mechanism behind enhanced Mg anode stability.

Main Methods:

• Comparative analysis of various Mg halides in magnesium bis(hexamethyldisilazide)-based electrolytes.
• Electrochemical testing of magnesium plating/stripping and battery cycling.
• In situ interface analysis to understand anode-electrolyte interactions.

Main Results:

• A novel MgBr₂-containing electrolyte demonstrated exceptional Mg plating/stripping efficiency (99.26% over 1000 cycles).
• The MgBr₂ electrolyte facilitated dendrite-free Mg deposition and stable cycling in Mg-Mo₆S₈ batteries for over 100 cycles.
• High anodic stability of 3.1 V was achieved with the new MgBr₂-based electrolyte.

Conclusions:

• MgBr₂ is a promising additive for advanced Mg battery electrolytes.
• The developed electrolyte enhances Mg anode stability and cycling performance.
• This work paves the way for practical, high-performance magnesium batteries.