Rationally Designed Li-Ag Alloy with In-Situ-Formed Solid Electrolyte Interphase for All-Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium batteries (ASSLBs) using sulfide electrolytes offer high energy density and safety.
• Challenges include lithium dendrite growth and side reactions at the lithium metal anode-sulfide electrolyte interface.
• These issues degrade ASSLB performance and pose safety risks.

Purpose of the Study:

• To develop a stable lithium metal anode for ASSLBs.
• To mitigate performance degradation caused by lithium dendrites and interfacial side reactions.
• To improve the overall safety and cycling stability of ASSLBs.

Main Methods:

• Preparation of a silver-based lithium (Li-Ag) alloy anode via electrodeposition.
• Characterization of the electrochemically formed solid electrolyte interphase (SEI) layer on the Li-Ag alloy.
• Assembly and testing of symmetric cells and full ASSLB cells using the Li-Ag anode.

Main Results:

• The SEI layer on the Li-Ag alloy, composed of LiF, Li₂O, and Li₃N, exhibited high mechanical strength and ionic conductivity.
• The Li-Ag alloy anode successfully suppressed lithium dendrite formation and cell short-circuiting.
• Symmetric cells demonstrated a critical current density of 1.6 mA cm^-2 and stable cycling over 2000 hours.
• A full ASSLB with the Li-Ag anode delivered a high discharge capacity of 185 mAh g^-1 with good cycling stability and rate capability.

Conclusions:

• The developed Li-Ag alloy anode with a robust SEI layer is a promising solution for stable ASSLBs.
• This anode design effectively addresses the critical challenges of lithium dendrite growth and interfacial instability.
• The findings pave the way for safer and higher-performance all-solid-state lithium batteries.