Li₂ S₆ -Integrated PEO-Based Polymer Electrolytes for All-Solid-State Lithium-Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state electrolytes are crucial for next-generation batteries.
• Achieving high ionic conductivity and stable interfaces remains a challenge for polymer electrolytes.

Purpose of the Study:

• To enhance the ionic conductivity and interfacial stability of poly(ethylene oxide) (PEO)-based polymer electrolytes.
• To investigate the effect of Li$_{2}$S$_{6}$ integration on the PEO matrix and the lithium metal interface.

Main Methods:

• Integration of Li$_{2}$S$_{6}$ into a PEO-based polymer electrolyte.
• Characterization of ionic conductivity and interfacial properties.
• Fabrication and testing of symmetric Li/Li cells and all-solid-state LiFePO$_{4}$ and LiNi$_{0.8}$Mn$_{0.1}$Co$_{0.1}$O$_{2}$ batteries.

Main Results:

• Li$_{2}$S$_{6}$ integration reduced the crystalline volume of PEO, enhancing ionic conductivity.
• An in situ formed Li$_{2}$S/Li$_{2}$S$_{2}$ layer at the Li/electrolyte interface improved ionic transport and suppressed dendrite growth.
• The symmetric Li/Li cell demonstrated excellent cyclability and a high critical current density of 0.9 mA cm$^{-2}$ at 40°C.

Conclusions:

• Li$_{2}$S$_{6}$-integrated PEO electrolytes offer a promising pathway for developing high-performance, safe solid-state lithium batteries.
• The enhanced interfacial stability and ionic transport are key to achieving superior electrochemical performance.