Li₃N-Enriched Solid Electrolyte Interphase Derived From Interfacial Catalysis Toward High-Performance Lithium Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Lithium metal batteries (LMBs) face commercialization hurdles due to lithium dendrite growth, caused by unstable solid electrolyte interphases (SEI).
• Achieving a Li3N-enriched SEI is crucial for high conductivity and mechanical strength, but the LiNO3-to-Li3N conversion faces kinetic barriers.

Purpose of the Study:

• To develop a catalytic approach for engineering Li3N-enriched SEI layers in LMBs.
• To overcome the kinetic barrier of LiNO3 reduction using transition metal single-atom catalysts.

Main Methods:

• Utilized transition metal single-atom catalysts supported on nitrogen-doped carbon (M/NC) to accelerate LiNO3 reduction.
• Investigated catalysts including Cr, Mn, Fe, Co, and Ni.
• Performed theoretical calculations to understand catalytic mechanisms.

Main Results:

• Co/NC demonstrated the highest catalytic activity, yielding an SEI with enhanced mechanical robustness and ionic transport.
• Theoretical calculations indicated Co/NC's superior performance is due to favorable electron transfer facilitated by minimal energy differences in frontier molecular orbitals.
• Symmetric batteries with Co/NC catalyst achieved over 2500 hours of cyclability (1 mA cm-2, 1 mAh cm-2).

Conclusions:

• Catalytic interfacial engineering is key to designing high-performance SEI for practical LMBs.
• The Co/NC catalyst effectively promotes Li3N formation, leading to stable and robust SEI layers.
• This approach significantly enhances the cycle life of both symmetric and full lithium metal cells.