An LLTO-containing heterogeneous composite electrolyte with a stable interface for solid-state lithium metal...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Interfacial instability between Li_0.33La_0.56TiO₃ (LLTO) and lithium metal anodes hinders solid-state electrolyte performance.
• This instability limits the practical application of LLTO-based solid-state electrolytes in lithium metal batteries.

Purpose of the Study:

• To design and fabricate a heterogeneous composite electrolyte (PVDF-HFP@LLTO/PEO or PLTP) to improve interfacial stability.
• To enhance the electrochemical performance of solid-state lithium metal batteries by addressing the LLTO/lithium metal anode interface.

Main Methods:

• Fabrication of a heterogeneous composite electrolyte (PLTP) by adhering a PEO layer to a PVDF-HFP@LLTO (PLT) membrane.
• Characterization of ionic conductivity and electrochemical window of the PLTP electrolyte.
• Assembly and testing of solid-state Li||LiFePO₄ and Li||LiNi_0.6Co_0.2Mn_0.2O₂ batteries using the PLTP electrolyte.

Main Results:

• The PLTP electrolyte achieved a superior ionic conductivity of 3.23 × 10^-4 S cm^-1 at 60 °C.
• A highly stable electrochemical window of up to 4.7 V (vs. Li/Li⁺) was observed.
• Significantly enhanced chemical stability at the electrolyte/lithium metal anode interface due to the PEO layer protection.
• Solid-state batteries demonstrated impressive electrochemical performance, including high Coulombic efficiency and stable cycling.

Conclusions:

• The heterogeneous PLTP composite electrolyte effectively mitigates interfacial instability in solid-state lithium metal batteries.
• The enhanced interfacial stability and electrochemical properties make PLTP a promising alternative for advanced solid-state battery development.