Rational design of a topological polymeric solid electrolyte for high-performance all-solid-state alkali metal...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Poly(ethylene oxide)-based solid-state electrolytes show promise for next-generation lithium and sodium metal batteries.
• Key challenges include limited oxidation resistance and low cation transference numbers, restricting their widespread application.

Purpose of the Study:

• To design, synthesize, and apply a novel fluoropolymer, poly(2,2,2-trifluoroethyl methacrylate), to enhance poly(ethylene oxide)-based solid electrolytes.
• To improve electrochemical window stability and cation transference number in solid-state electrolytes.

Main Methods:

• Synthesis and characterization of poly(2,2,2-trifluoroethyl methacrylate).
• Incorporation of the fluoropolymer into poly(ethylene oxide)-based solid electrolytes.
• Physicochemical and theoretical characterizations to understand performance improvements.
• Fabrication and testing of full lithium and sodium metal lab-scale cells.

Main Results:

• The fluoropolymer incorporation significantly improves electrochemical window stability and cation transference number.
• Tailored supramolecular bonds and unique morphological structures were identified as key factors for enhanced performance.
• Lab-scale lithium metal cells demonstrated stable cycling for 200 cycles at 42 mA·g⁻¹ and 70°C with a LiMn_0.6Fe_0.4PO₄ cathode.

Conclusions:

• Poly(2,2,2-trifluoroethyl methacrylate) is an effective additive for improving poly(ethylene oxide)-based solid electrolytes.
• The enhanced electrolytes show potential for stable and high-performance lithium and sodium metal batteries.
• The study highlights the importance of supramolecular interactions and morphology in solid-state electrolyte design.