A Stable Solid Electrolyte Interphase for Magnesium Metal Anode Evolved from a Bulky Anion Lithium Salt

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable magnesium (Mg) batteries are promising post-lithium-ion energy storage systems.
• Challenges include the formation of passivating surface films on Mg anodes, hindering Mg2+ ion conduction.
• Developing a stable solid electrolyte interphase (SEI) is crucial for Mg battery performance.

Purpose of the Study:

• To construct a stable SEI on Mg metal anodes.
• To develop a novel electrolyte enabling stable rechargeable Mg batteries.
• To overcome limitations in Mg battery development.

Main Methods:

• Preparation of a Li-based electrolyte using lithium tetrakis(hexafluoroisopropyloxy)borate (Li[B(hfip)4]) in dimethoxyethane.
• Electrochemical cycling to induce partial decomposition of the Li electrolyte.
• In situ formation of a hybrid Mg2+/Li+ electrolyte and SEI layer.

Main Results:

• A stable SEI layer was successfully constructed on the Mg metal anode surface.
• The formed SEI effectively blocked parasitic reactions between the Mg anode and electrolyte.
• The novel electrolyte demonstrated stable long-term electrochemical cycling performance.

Conclusions:

• The developed approach provides a new strategy for creating superior SEI layers on Mg anodes.
• This work offers a novel electrolyte system for high-performance rechargeable Mg batteries.
• The findings pave the way for the practical application of Mg metal batteries.