Long-cycling and High-voltage Solid State Lithium Metal Batteries Enabled by Fluorinated and Crosslinked Polyether...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid-state lithium metal batteries (LMBs) offer high energy density and safety but are limited by polymer electrolyte oxidation stability.
• Polyethers, commonly used polymer electrolytes, restrict applications in high-voltage batteries.

Purpose of the Study:

• To develop a novel polymer electrolyte with enhanced oxidation stability for high-voltage LMBs.
• To improve the compatibility of polymer electrolytes with lithium metal and high-voltage cathodes.

Main Methods:

• In situ fabrication of a fluorinated and crosslinked polyether-based gel polymer electrolyte (FGPE).
• Electrochemical characterization including oxidation potential measurements.
• Battery performance testing using Li||LiNi0.6Co0.2Mn0.2O2 cells under various conditions.

Main Results:

• FGPE exhibits a high oxidation potential of 5.1 V.
• Batteries with FGPE demonstrate excellent cycling stability (1000 cycles, 78% retention) and operate at 4.7 V.
• Stable performance was achieved in practical conditions, including high cathode loading and 18650-type cells.

Conclusions:

• The fluorinated polyether electrolyte significantly enhances oxidation stability and interfacial compatibility.
• FGPE enables practical high-voltage LMBs with improved safety and energy density.
• This research provides insights for developing advanced polymer electrolytes for next-generation batteries.