Hydrogen-Bond and Solvation-Shell Dual Modulation Enables Safe Gel Polymer Electrolyte for Lithium Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Lithium metal batteries offer high energy density but face challenges with interfacial instability, dendrite formation, and safety concerns.
• Existing gel polymer electrolytes often exhibit poor interfacial compatibility and fail to prevent lithium dendrite growth.

Purpose of the Study:

• To design and develop an in situ formed nonflammable gel polymer electrolyte (NGPE) for stable and safe lithium metal batteries.
• To address interfacial instability and dendrite growth using molecular-level strategies.

Main Methods:

• Integration of hydrogen-bond anchoring (TMP, PVDF-HFP, TFSI-) to immobilize anions and enhance ionic conductivity.
• Solvation-shell regulation using fluoroethylene carbonate to create inorganic-rich interphases.
• In situ formation of the NGPE for improved interfacial compatibility.

Main Results:

• The optimized NGPE demonstrated stable Li||Li cycling for over 2800 hours.
• Li||LFP full cells maintained 74.3% capacity retention after 1000 cycles at 2 C.
• Pouch cells exhibited mechanical robustness and exceptional safety, passing flame tests.

Conclusions:

• The dual molecular strategy provides a general design principle for developing safe, dendrite-free, quasi-solid-state lithium metal batteries.
• The NGPE effectively suppresses dendrites and stabilizes interfaces, paving the way for advanced energy storage solutions.