Electrolyte Additive Enabling Conditioning-Free Electrolytes for Magnesium Batteries.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable magnesium batteries offer high energy density but are hindered by slow conditioning processes.
• Achieving reversible magnesium deposition/dissolution typically requires extensive precycling, limiting practical application.

Purpose of the Study:

• To develop a simple method to eliminate the conditioning process in rechargeable Mg batteries.
• To enhance the initial Coulombic efficiency and current density of Mg deposition/dissolution.

Main Methods:

• Investigated the use of heptamethyldisilazane (HpMS) as an electrolyte additive.
• Tested HpMS in various sulfone and glyme electrolytes with MgCl2 or Mg(TFSI)2 salts.
• Analyzed Mg deposition/dissolution behavior during initial battery cycles.

Main Results:

• HpMS additive significantly increased current density and Coulombic efficiency from the first cycle.
• The additive proved effective in diverse electrolyte systems (sulfone, glyme) and salt types (MgCl2, Mg(TFSI)2).
• HpMS functions by scavenging trace water and removing surface decomposition products like Mg(OH)2.

Conclusions:

• HpMS effectively eliminates the conditioning requirement for rechargeable Mg batteries.
• The additive's broad applicability across Mg electrolytes is confirmed.
• HpMS is poised to accelerate the commercialization of practical Mg battery technology.