Highly active electrolytes for rechargeable Mg batteries based on a [Mg2(μ-Cl)2](2+) cation complex in...

Area of Science:

• Electrochemistry
• Materials Science
• Inorganic Chemistry

Background:

• Magnesium batteries offer high energy density but face challenges with electrolyte stability and reversible magnesium electrodeposition.
• Developing suitable electrolytes is critical for realizing the potential of magnesium-based energy storage systems.

Purpose of the Study:

• To identify and characterize a novel cation complex enabling highly active reversible magnesium electrodeposition.
• To develop rational strategies for formulating advanced magnesium battery electrolytes.

Main Methods:

• Synthesis of electrolytes in dimethoxyethane (DME) via dehalodimerization of magnesium chloride.
• Characterization of the cation complex using single crystal X-ray diffraction, Raman spectroscopy, and Nuclear Magnetic Resonance (NMR).
• Electrochemical evaluation of electrolyte performance, including efficiency, electrochemical window, and ionic conductivity.

Main Results:

• Identification of the novel [Mg2(μ-Cl)2](2+) cation complex, active for reversible Mg electrodeposition.
• Demonstration of electrolytes with near 100% efficiency, a 3.5 V electrochemical window, and ionic conductivity >6 mS cm(-1).
• Establishment of rational approaches for electrolyte formulation based on controlling anions.

Conclusions:

• The novel [Mg2(μ-Cl)2](2+) complex is key to high-performance magnesium electrolytes.
• Understanding electrolyte synthesis in DME facilitates the rational design of electrolytes for practical magnesium batteries.
• This work provides a pathway for developing advanced magnesium battery technologies.