A Dual Functional Artificial SEI Layer Based on a Facile Surface Chemistry for Stable Lithium Metal Anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The solid electrolyte interphase (SEI) is crucial for Li metal battery stability and longevity.
• Existing SEI strategies often focus on either passivation or active site effects, limiting overall performance.
• Achieving ideal Li anode performance requires a simultaneous approach to interfacial management.

Purpose of the Study:

• To develop a dual functional artificial SEI layer for Li metal anodes.
• To simultaneously incorporate passivation and active site effects for improved interfacial properties.
• To enhance the stability and cycle life of Li metal batteries.

Main Methods:

• Fabrication of a dual functional artificial SEI layer using surface chemistry.
• Characterization of the SEI layer's composition and structure (LiF and Li-Mg alloy).
• Electrochemical testing of Li||Li symmetric cells and Li||LiFePO4 full cells.

Main Results:

• The dual functional SEI layer effectively passivates the anode/electrolyte interface.
• The Li-Mg alloy component promotes Li+ transmission and homogeneous Li deposition.
• Achieved a low nucleation overpotential (2.3 mV) and ultralong cycling (>2000 h) in Li||Li cells.
• Demonstrated 84.6% capacity retention in Li||LiFePO4 full cells after 300 cycles.

Conclusions:

• The proposed dual functional artificial SEI layer significantly enhances Li anode performance.
• Simultaneous passivation and active site effects are key to stable and efficient Li metal batteries.
• This approach offers a promising strategy for developing next-generation high-performance batteries.