Interfacial percolation enables high-conductivity lean-lithium oxychloride electrolytes for all-solid-state batteries

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Inorganic solid-state electrolytes (SSEs) are crucial for all-solid-state batteries (ASSBs).
• Current SSEs require high lithium (Li) content, increasing cost and reducing stability.
• This limits the performance and safety of ASSBs.

Purpose of the Study:

• To develop a novel interfacial percolation strategy for SSEs.
• To achieve high ionic conductivity in SSEs with lean-Li content.
• To enhance the electrochemical stability and overall performance of ASSBs.

Main Methods:

• Fabrication of a percolative SSE (Ta2O5·a-LTOC) with Ta2O5 nanocrystals in an amorphous matrix.
• Characterization of ionic conductivity and Li content.
• High-voltage stability testing.
• Fabrication and testing of ASSBs with high-nickel cathodes.

Main Results:

• The Ta2O5·a-LTOC achieved high ionic conductivity (15.2 mS cm-1) at low Li content (1.46 wt%).
• Demonstrated high-voltage stability up to 4.8 V.
• ASSBs exhibited excellent cycle life (5000 cycles at 2C), high-rate cycling (4000 cycles at 6C), and high-loading performance (>3 mAh cm-2).

Conclusions:

• The interfacial percolation strategy enables lean-Li, highly conductive SSEs.
• This approach breaks the dependence of conductivity on high Li content.
• The strategy offers a universal design for high-energy, fast-charging ASSBs.