Self-Adaptive Superionic Electrolytes via Multiple-Cation Modulation for All-Solid-State Lithium-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium-metal batteries promise high energy density and safety.
• Interfacial instability at the lithium metal/electrolyte interface hinders practical application, especially under high current densities.
• Current stabilization methods are complex and costly, necessitating simpler electrolyte design strategies.

Purpose of the Study:

• To develop a simple yet effective solid-state electrolyte design for improved interfacial stability and ionic conductivity.
• To investigate the in situ modification of the lithium metal anode and solid electrolyte interface (SEI) using a novel electrolyte composition.
• To advance the practical application of all-solid-state lithium-metal batteries through enhanced performance and stability.

Main Methods:

• Development of a multiple-cation-presetting (Ag and W) argyrodite solid-state electrolyte.
• In situ analysis of interfacial reactions and lithium metal anode modification during battery cycling.
• Electrochemical testing of lithium symmetric cells and Li//LiNi$_{0.8}$Co$_{0.1}$Mn$_{0.1}$O$_{2}$ full cells under various conditions.

Main Results:

• The developed electrolyte exhibits superionic conductivity (>10 mS cm$^{-1}$) and enhanced interfacial stability.
• In situ formation of a uniform Li-Ag alloy on the anode and a conductive LiWS$_{2}$ layer in the SEI.
• Sustained cycling of Li symmetric cells over 4000 h at 0.5 mA cm$^{-2}$ and 1000 h at 1 mA cm$^{-2}$.
• Full cells show 82.7% capacity retention after 1100 cycles at 2C, with stable operation at high areal loading and low temperatures (-30 °C).

Conclusions:

• The dual-cation argyrodite electrolyte effectively stabilizes the lithium metal interface through in situ anode modification.
• This strategy significantly improves the cycling stability, rate capability, and operational range of all-solid-state lithium-metal batteries.
• The scalable dual-cation modulation offers a general route for designing advanced solid-state electrolytes for next-generation energy storage devices.