Flexible Sulfide Electrolyte Thin Membrane with Ultrahigh Ionic Conductivity for All-Solid-State Lithium Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium batteries (ASSLBs) offer high energy density and safety.
• Challenges include thick solid electrolyte (SE) separators and low ionic conductivity.
• Improving SE properties is crucial for practical ASSLB development.

Purpose of the Study:

• To develop a high-performance sulfide solid electrolyte (SE) membrane for ASSLBs.
• To enhance the anodic stability of the SE/Li interface.
• To demonstrate the feasibility of practical high-performance ASSLBs.

Main Methods:

• Mechanized manufacturing of a 30 μm Li$_{5.4}$PS$_{4.4}$Cl$_{1.6}$ SE membrane with high ionic conductivity (8.4 mS cm$^{-1}$).
• Magnetron sputtering of a 400 nm Al$_{2}$O$_{3}$ interlayer at the SE/Li interface.
• Fabrication and testing of ASSLBs using LiNi$_{0.5}$Co$_{0.2}$Mn$_{0.3}$O$_{2}$ cathode and Li-metal anode.

Main Results:

• Achieved ultrahigh room temperature ionic conductivity of 8.4 mS cm$^{-1}$ in the SE membrane.
• The Al$_{2}$O$_{3}$ interlayer suppressed short circuits in Li/Li symmetric cells, enhancing anodic stability.
• ASSLBs demonstrated stable cycling with 80.2% capacity retention after 150 cycles and >99.5% Coulombic efficiency.

Conclusions:

• The developed SE membrane and interface strategy are promising for high-performance ASSLBs.
• Mechanized manufacturing and interface engineering are key for practical ASSLB realization.
• This work paves the way for safer, high-energy-density solid-state batteries.